binutils-gdb/libctf/ctf-open.c

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libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
/* Opening CTF files.
Copyright (C) 2019 Free Software Foundation, Inc.
This file is part of libctf.
libctf is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; see the file COPYING. If not see
<http://www.gnu.org/licenses/>. */
#include <ctf-impl.h>
#include <stddef.h>
#include <string.h>
#include <sys/types.h>
#include <elf.h>
#include <assert.h>
#include "swap.h"
#include <bfd.h>
#include <zlib.h>
#include "elf-bfd.h"
static const ctf_dmodel_t _libctf_models[] = {
{"ILP32", CTF_MODEL_ILP32, 4, 1, 2, 4, 4},
{"LP64", CTF_MODEL_LP64, 8, 1, 2, 4, 8},
{NULL, 0, 0, 0, 0, 0, 0}
};
const char _CTF_SECTION[] = ".ctf";
const char _CTF_NULLSTR[] = "";
/* Version-sensitive accessors. */
static uint32_t
get_kind_v1 (uint32_t info)
{
return (CTF_V1_INFO_KIND (info));
}
static uint32_t
get_root_v1 (uint32_t info)
{
return (CTF_V1_INFO_ISROOT (info));
}
static uint32_t
get_vlen_v1 (uint32_t info)
{
return (CTF_V1_INFO_VLEN (info));
}
static uint32_t
get_kind_v2 (uint32_t info)
{
return (CTF_V2_INFO_KIND (info));
}
static uint32_t
get_root_v2 (uint32_t info)
{
return (CTF_V2_INFO_ISROOT (info));
}
static uint32_t
get_vlen_v2 (uint32_t info)
{
return (CTF_V2_INFO_VLEN (info));
}
static inline ssize_t
get_ctt_size_common (const ctf_file_t *fp _libctf_unused_,
const ctf_type_t *tp _libctf_unused_,
ssize_t *sizep, ssize_t *incrementp, size_t lsize,
size_t csize, size_t ctf_type_size,
size_t ctf_stype_size, size_t ctf_lsize_sent)
{
ssize_t size, increment;
if (csize == ctf_lsize_sent)
{
size = lsize;
increment = ctf_type_size;
}
else
{
size = csize;
increment = ctf_stype_size;
}
if (sizep)
*sizep = size;
if (incrementp)
*incrementp = increment;
return size;
}
static ssize_t
get_ctt_size_v1 (const ctf_file_t *fp, const ctf_type_t *tp,
ssize_t *sizep, ssize_t *incrementp)
{
ctf_type_v1_t *t1p = (ctf_type_v1_t *) tp;
return (get_ctt_size_common (fp, tp, sizep, incrementp,
CTF_TYPE_LSIZE (t1p), t1p->ctt_size,
sizeof (ctf_type_v1_t), sizeof (ctf_stype_v1_t),
CTF_LSIZE_SENT_V1));
}
/* Return the size that a v1 will be once it is converted to v2. */
static ssize_t
get_ctt_size_v2_unconverted (const ctf_file_t *fp, const ctf_type_t *tp,
ssize_t *sizep, ssize_t *incrementp)
{
ctf_type_v1_t *t1p = (ctf_type_v1_t *) tp;
return (get_ctt_size_common (fp, tp, sizep, incrementp,
CTF_TYPE_LSIZE (t1p), t1p->ctt_size,
sizeof (ctf_type_t), sizeof (ctf_stype_t),
CTF_LSIZE_SENT));
}
static ssize_t
get_ctt_size_v2 (const ctf_file_t *fp, const ctf_type_t *tp,
ssize_t *sizep, ssize_t *incrementp)
{
return (get_ctt_size_common (fp, tp, sizep, incrementp,
CTF_TYPE_LSIZE (tp), tp->ctt_size,
sizeof (ctf_type_t), sizeof (ctf_stype_t),
CTF_LSIZE_SENT));
}
static ssize_t
get_vbytes_common (unsigned short kind, ssize_t size _libctf_unused_,
size_t vlen)
{
switch (kind)
{
case CTF_K_INTEGER:
case CTF_K_FLOAT:
return (sizeof (uint32_t));
case CTF_K_SLICE:
libctf: endianness fixes Testing of the first code to generate CTF_K_SLICEs on big-endian revealed a bunch of new problems in this area. Most importantly, the trick we did earlier to avoid wasting two bytes on padding in the ctf_slice_t is best avoided: because it leads to the whole file after that point no longer being naturally aligned, all multibyte accesses from then on must use memmove() to avoid unaligned access on platforms where that is fatal. In future, this is planned, but for now we are still doing direct access in many places, so we must revert to making ctf_slice_t properly aligned for storage in an array. Rather than wasting bytes on padding, we boost the size of cts_offset and cts_bits. This is still a waste of space (we cannot have offsets or bits in bitfields > 256) but it cannot be avoided for now, and slices are not so common that this will be a serious problem. A possibly-worse endianness problem fixed at the same time involves a codepath used only for foreign-endian, uncompressed CTF files, where we were not copying the actual CTF data into the buffer, leading to libctf reading only zeroes (or, possibly, uninitialized garbage). Finally, when we read in a CTF file, we copy the header and work from the copy. We were flipping the endianness of the header copy, and of the body of the file buffer, but not of the header in the file buffer itself: so if we write the file back out again we end up with an unreadable frankenfile with header and body of different endiannesses. Fix by flipping both copies of the header. include/ * ctf.h (ctf_slice_t): Make cts_offset and cts_bits unsigned short, so following structures are properly aligned. libctf/ * ctf-open.c (get_vbytes_common): Return the new slice size. (ctf_bufopen): Flip the endianness of the CTF-section header copy. Remember to copy in the CTF data when opening an uncompressed foreign-endian CTF file. Prune useless variable manipulation.
2019-06-19 19:34:56 +08:00
return (sizeof (ctf_slice_t));
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
case CTF_K_ENUM:
return (sizeof (ctf_enum_t) * vlen);
case CTF_K_FORWARD:
case CTF_K_UNKNOWN:
case CTF_K_POINTER:
case CTF_K_TYPEDEF:
case CTF_K_VOLATILE:
case CTF_K_CONST:
case CTF_K_RESTRICT:
return 0;
default:
ctf_dprintf ("detected invalid CTF kind -- %x\n", kind);
return ECTF_CORRUPT;
}
}
static ssize_t
get_vbytes_v1 (unsigned short kind, ssize_t size, size_t vlen)
{
switch (kind)
{
case CTF_K_ARRAY:
return (sizeof (ctf_array_v1_t));
case CTF_K_FUNCTION:
return (sizeof (unsigned short) * (vlen + (vlen & 1)));
case CTF_K_STRUCT:
case CTF_K_UNION:
if (size < CTF_LSTRUCT_THRESH_V1)
return (sizeof (ctf_member_v1_t) * vlen);
else
return (sizeof (ctf_lmember_v1_t) * vlen);
}
return (get_vbytes_common (kind, size, vlen));
}
static ssize_t
get_vbytes_v2 (unsigned short kind, ssize_t size, size_t vlen)
{
switch (kind)
{
case CTF_K_ARRAY:
return (sizeof (ctf_array_t));
case CTF_K_FUNCTION:
return (sizeof (uint32_t) * (vlen + (vlen & 1)));
case CTF_K_STRUCT:
case CTF_K_UNION:
if (size < CTF_LSTRUCT_THRESH)
return (sizeof (ctf_member_t) * vlen);
else
return (sizeof (ctf_lmember_t) * vlen);
}
return (get_vbytes_common (kind, size, vlen));
}
static const ctf_fileops_t ctf_fileops[] = {
{NULL, NULL, NULL, NULL, NULL},
/* CTF_VERSION_1 */
{get_kind_v1, get_root_v1, get_vlen_v1, get_ctt_size_v1, get_vbytes_v1},
/* CTF_VERSION_1_UPGRADED_3 */
{get_kind_v2, get_root_v2, get_vlen_v2, get_ctt_size_v2, get_vbytes_v2},
/* CTF_VERSION_2 */
{get_kind_v2, get_root_v2, get_vlen_v2, get_ctt_size_v2, get_vbytes_v2},
/* CTF_VERSION_3, identical to 2: only new type kinds */
{get_kind_v2, get_root_v2, get_vlen_v2, get_ctt_size_v2, get_vbytes_v2},
};
/* Initialize the symtab translation table by filling each entry with the
offset of the CTF type or function data corresponding to each STT_FUNC or
STT_OBJECT entry in the symbol table. */
static int
init_symtab (ctf_file_t *fp, const ctf_header_t *hp,
const ctf_sect_t *sp, const ctf_sect_t *strp)
{
const unsigned char *symp = sp->cts_data;
uint32_t *xp = fp->ctf_sxlate;
uint32_t *xend = xp + fp->ctf_nsyms;
uint32_t objtoff = hp->cth_objtoff;
uint32_t funcoff = hp->cth_funcoff;
uint32_t info, vlen;
Elf64_Sym sym, *gsp;
const char *name;
/* The CTF data object and function type sections are ordered to match
the relative order of the respective symbol types in the symtab.
If no type information is available for a symbol table entry, a
pad is inserted in the CTF section. As a further optimization,
anonymous or undefined symbols are omitted from the CTF data. */
for (; xp < xend; xp++, symp += sp->cts_entsize)
{
if (sp->cts_entsize == sizeof (Elf32_Sym))
gsp = ctf_sym_to_elf64 ((Elf32_Sym *) (uintptr_t) symp, &sym);
else
gsp = (Elf64_Sym *) (uintptr_t) symp;
if (gsp->st_name < strp->cts_size)
name = (const char *) strp->cts_data + gsp->st_name;
else
name = _CTF_NULLSTR;
if (gsp->st_name == 0 || gsp->st_shndx == SHN_UNDEF
|| strcmp (name, "_START_") == 0 || strcmp (name, "_END_") == 0)
{
*xp = -1u;
continue;
}
switch (ELF64_ST_TYPE (gsp->st_info))
{
case STT_OBJECT:
if (objtoff >= hp->cth_funcoff
|| (gsp->st_shndx == SHN_EXTABS && gsp->st_value == 0))
{
*xp = -1u;
break;
}
*xp = objtoff;
objtoff += sizeof (uint32_t);
break;
case STT_FUNC:
if (funcoff >= hp->cth_objtidxoff)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
*xp = -1u;
break;
}
*xp = funcoff;
info = *(uint32_t *) ((uintptr_t) fp->ctf_buf + funcoff);
vlen = LCTF_INFO_VLEN (fp, info);
/* If we encounter a zero pad at the end, just skip it. Otherwise
skip over the function and its return type (+2) and the argument
list (vlen).
*/
if (LCTF_INFO_KIND (fp, info) == CTF_K_UNKNOWN && vlen == 0)
funcoff += sizeof (uint32_t); /* Skip pad. */
else
funcoff += sizeof (uint32_t) * (vlen + 2);
break;
default:
*xp = -1u;
break;
}
}
ctf_dprintf ("loaded %lu symtab entries\n", fp->ctf_nsyms);
return 0;
}
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
/* Reset the CTF base pointer and derive the buf pointer from it, initializing
everything in the ctf_file that depends on the base or buf pointers.
The original gap between the buf and base pointers, if any -- the original,
unconverted CTF header -- is kept, but its contents are not specified and are
never used. */
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
static void
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
ctf_set_base (ctf_file_t *fp, const ctf_header_t *hp, unsigned char *base)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
fp->ctf_buf = base + (fp->ctf_buf - fp->ctf_base);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
fp->ctf_base = base;
fp->ctf_vars = (ctf_varent_t *) ((const char *) fp->ctf_buf +
hp->cth_varoff);
fp->ctf_nvars = (hp->cth_typeoff - hp->cth_varoff) / sizeof (ctf_varent_t);
fp->ctf_str[CTF_STRTAB_0].cts_strs = (const char *) fp->ctf_buf
+ hp->cth_stroff;
fp->ctf_str[CTF_STRTAB_0].cts_len = hp->cth_strlen;
/* If we have a parent container name and label, store the relocated
string pointers in the CTF container for easy access later. */
/* Note: before conversion, these will be set to values that will be
immediately invalidated by the conversion process, but the conversion
process will call ctf_set_base() again to fix things up. */
if (hp->cth_parlabel != 0)
fp->ctf_parlabel = ctf_strptr (fp, hp->cth_parlabel);
if (hp->cth_parname != 0)
fp->ctf_parname = ctf_strptr (fp, hp->cth_parname);
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if (hp->cth_cuname != 0)
fp->ctf_cuname = ctf_strptr (fp, hp->cth_cuname);
if (fp->ctf_cuname)
ctf_dprintf ("ctf_set_base: CU name %s\n", fp->ctf_cuname);
if (fp->ctf_parname)
ctf_dprintf ("ctf_set_base: parent name %s (label %s)\n",
fp->ctf_parname,
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
fp->ctf_parlabel ? fp->ctf_parlabel : "<NULL>");
}
/* Set the version of the CTF file. */
/* When this is reset, LCTF_* changes behaviour, but there is no guarantee that
the variable data list associated with each type has been upgraded: the
caller must ensure this has been done in advance. */
static void
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
ctf_set_version (ctf_file_t *fp, ctf_header_t *cth, int ctf_version)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
fp->ctf_version = ctf_version;
cth->cth_version = ctf_version;
fp->ctf_fileops = &ctf_fileops[ctf_version];
}
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
/* Upgrade the header to CTF_VERSION_3. The upgrade is done in-place. */
static void
upgrade_header (ctf_header_t *hp)
{
ctf_header_v2_t *oldhp = (ctf_header_v2_t *) hp;
hp->cth_strlen = oldhp->cth_strlen;
hp->cth_stroff = oldhp->cth_stroff;
hp->cth_typeoff = oldhp->cth_typeoff;
hp->cth_varoff = oldhp->cth_varoff;
hp->cth_funcidxoff = hp->cth_varoff; /* No index sections. */
hp->cth_objtidxoff = hp->cth_funcidxoff;
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
hp->cth_funcoff = oldhp->cth_funcoff;
hp->cth_objtoff = oldhp->cth_objtoff;
hp->cth_lbloff = oldhp->cth_lbloff;
hp->cth_cuname = 0; /* No CU name. */
}
/* Upgrade the type table to CTF_VERSION_3 (really CTF_VERSION_1_UPGRADED_3)
from CTF_VERSION_1.
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
The upgrade is not done in-place: the ctf_base is moved. ctf_strptr() must
not be called before reallocation is complete.
Sections not checked here due to nonexistence or nonpopulated state in older
formats: objtidx, funcidx.
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
Type kinds not checked here due to nonexistence in older formats:
CTF_K_SLICE. */
static int
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
upgrade_types_v1 (ctf_file_t *fp, ctf_header_t *cth)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
const ctf_type_v1_t *tbuf;
const ctf_type_v1_t *tend;
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
unsigned char *ctf_base, *old_ctf_base = (unsigned char *) fp->ctf_dynbase;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
ctf_type_t *t2buf;
ssize_t increase = 0, size, increment, v2increment, vbytes, v2bytes;
const ctf_type_v1_t *tp;
ctf_type_t *t2p;
tbuf = (ctf_type_v1_t *) (fp->ctf_buf + cth->cth_typeoff);
tend = (ctf_type_v1_t *) (fp->ctf_buf + cth->cth_stroff);
/* Much like init_types(), this is a two-pass process.
First, figure out the new type-section size needed. (It is possible,
in theory, for it to be less than the old size, but this is very
unlikely. It cannot be so small that cth_typeoff ends up of negative
size. We validate this with an assertion below.)
We must cater not only for changes in vlen and types sizes but also
for changes in 'increment', which happen because v2 places some types
into ctf_stype_t where v1 would be forced to use the larger non-stype. */
for (tp = tbuf; tp < tend;
tp = (ctf_type_v1_t *) ((uintptr_t) tp + increment + vbytes))
{
unsigned short kind = CTF_V1_INFO_KIND (tp->ctt_info);
unsigned long vlen = CTF_V1_INFO_VLEN (tp->ctt_info);
size = get_ctt_size_v1 (fp, (const ctf_type_t *) tp, NULL, &increment);
vbytes = get_vbytes_v1 (kind, size, vlen);
get_ctt_size_v2_unconverted (fp, (const ctf_type_t *) tp, NULL,
&v2increment);
v2bytes = get_vbytes_v2 (kind, size, vlen);
if ((vbytes < 0) || (size < 0))
return ECTF_CORRUPT;
increase += v2increment - increment; /* May be negative. */
increase += v2bytes - vbytes;
}
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
/* Allocate enough room for the new buffer, then copy everything but the type
section into place, and reset the base accordingly. Leave the version
number unchanged, so that LCTF_INFO_* still works on the
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
as-yet-untranslated type info. */
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
if ((ctf_base = malloc (fp->ctf_size + increase)) == NULL)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return ECTF_ZALLOC;
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
/* Start at ctf_buf, not ctf_base, to squeeze out the original header: we
never use it and it is unconverted. */
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
memcpy (ctf_base, fp->ctf_buf, cth->cth_typeoff);
memcpy (ctf_base + cth->cth_stroff + increase,
fp->ctf_buf + cth->cth_stroff, cth->cth_strlen);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
memset (ctf_base + cth->cth_typeoff, 0, cth->cth_stroff - cth->cth_typeoff
+ increase);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
cth->cth_stroff += increase;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
fp->ctf_size += increase;
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
assert (cth->cth_stroff >= cth->cth_typeoff);
fp->ctf_base = ctf_base;
fp->ctf_buf = ctf_base;
fp->ctf_dynbase = ctf_base;
ctf_set_base (fp, cth, ctf_base);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
t2buf = (ctf_type_t *) (fp->ctf_buf + cth->cth_typeoff);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
/* Iterate through all the types again, upgrading them.
Everything that hasn't changed can just be outright memcpy()ed.
Things that have changed need field-by-field consideration. */
for (tp = tbuf, t2p = t2buf; tp < tend;
tp = (ctf_type_v1_t *) ((uintptr_t) tp + increment + vbytes),
t2p = (ctf_type_t *) ((uintptr_t) t2p + v2increment + v2bytes))
{
unsigned short kind = CTF_V1_INFO_KIND (tp->ctt_info);
int isroot = CTF_V1_INFO_ISROOT (tp->ctt_info);
unsigned long vlen = CTF_V1_INFO_VLEN (tp->ctt_info);
ssize_t v2size;
void *vdata, *v2data;
size = get_ctt_size_v1 (fp, (const ctf_type_t *) tp, NULL, &increment);
vbytes = get_vbytes_v1 (kind, size, vlen);
t2p->ctt_name = tp->ctt_name;
t2p->ctt_info = CTF_TYPE_INFO (kind, isroot, vlen);
switch (kind)
{
case CTF_K_FUNCTION:
case CTF_K_FORWARD:
case CTF_K_TYPEDEF:
case CTF_K_POINTER:
case CTF_K_VOLATILE:
case CTF_K_CONST:
case CTF_K_RESTRICT:
t2p->ctt_type = tp->ctt_type;
break;
case CTF_K_INTEGER:
case CTF_K_FLOAT:
case CTF_K_ARRAY:
case CTF_K_STRUCT:
case CTF_K_UNION:
case CTF_K_ENUM:
case CTF_K_UNKNOWN:
libctf: fix a number of build problems found on Solaris and NetBSD - Use of nonportable <endian.h> - Use of qsort_r - Use of zlib without appropriate magic to pull in the binutils zlib - Use of off64_t without checking (fixed by dropping the unused fields that need off64_t entirely) - signedness problems due to long being too short a type on 32-bit platforms: ctf_id_t is now 'unsigned long', and CTF_ERR must be used only for functions that return ctf_id_t - One lingering use of bzero() and of <sys/errno.h> All fixed, using code from gnulib where possible. Relatedly, set cts_size in a couple of places it was missed (string table and symbol table loading upon ctf_bfdopen()). binutils/ * objdump.c (make_ctfsect): Drop cts_type, cts_flags, and cts_offset. * readelf.c (shdr_to_ctf_sect): Likewise. include/ * ctf-api.h (ctf_sect_t): Drop cts_type, cts_flags, and cts_offset. (ctf_id_t): This is now an unsigned type. (CTF_ERR): Cast it to ctf_id_t. Note that it should only be used for ctf_id_t-returning functions. libctf/ * Makefile.am (ZLIB): New. (ZLIBINC): Likewise. (AM_CFLAGS): Use them. (libctf_a_LIBADD): New, for LIBOBJS. * configure.ac: Check for zlib, endian.h, and qsort_r. * ctf-endian.h: New, providing htole64 and le64toh. * swap.h: Code style fixes. (bswap_identity_64): New. * qsort_r.c: New, from gnulib (with one added #include). * ctf-decls.h: New, providing a conditional qsort_r declaration, and unconditional definitions of MIN and MAX. * ctf-impl.h: Use it. Do not use <sys/errno.h>. (ctf_set_errno): Now returns unsigned long. * ctf-util.c (ctf_set_errno): Adjust here too. * ctf-archive.c: Use ctf-endian.h. (ctf_arc_open_by_offset): Use memset, not bzero. Drop cts_type, cts_flags and cts_offset. (ctf_arc_write): Drop debugging dependent on the size of off_t. * ctf-create.c: Provide a definition of roundup if not defined. (ctf_create): Drop cts_type, cts_flags and cts_offset. (ctf_add_reftype): Do not check if type IDs are below zero. (ctf_add_slice): Likewise. (ctf_add_typedef): Likewise. (ctf_add_member_offset): Cast error-returning ssize_t's to size_t when known error-free. Drop CTF_ERR usage for functions returning int. (ctf_add_member_encoded): Drop CTF_ERR usage for functions returning int. (ctf_add_variable): Likewise. (enumcmp): Likewise. (enumadd): Likewise. (membcmp): Likewise. (ctf_add_type): Likewise. Cast error-returning ssize_t's to size_t when known error-free. * ctf-dump.c (ctf_is_slice): Drop CTF_ERR usage for functions returning int: use CTF_ERR for functions returning ctf_type_id. (ctf_dump_label): Likewise. (ctf_dump_objts): Likewise. * ctf-labels.c (ctf_label_topmost): Likewise. (ctf_label_iter): Likewise. (ctf_label_info): Likewise. * ctf-lookup.c (ctf_func_args): Likewise. * ctf-open.c (upgrade_types): Cast to size_t where appropriate. (ctf_bufopen): Likewise. Use zlib types as needed. * ctf-types.c (ctf_member_iter): Drop CTF_ERR usage for functions returning int. (ctf_enum_iter): Likewise. (ctf_type_size): Likewise. (ctf_type_align): Likewise. Cast to size_t where appropriate. (ctf_type_kind_unsliced): Likewise. (ctf_type_kind): Likewise. (ctf_type_encoding): Likewise. (ctf_member_info): Likewise. (ctf_array_info): Likewise. (ctf_enum_value): Likewise. (ctf_type_rvisit): Likewise. * ctf-open-bfd.c (ctf_bfdopen): Drop cts_type, cts_flags and cts_offset. (ctf_simple_open): Likewise. (ctf_bfdopen_ctfsect): Likewise. Set cts_size properly. * Makefile.in: Regenerate. * aclocal.m4: Likewise. * config.h: Likewise. * configure: Likewise.
2019-05-31 17:10:51 +08:00
if ((size_t) size <= CTF_MAX_SIZE)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
t2p->ctt_size = size;
else
{
t2p->ctt_lsizehi = CTF_SIZE_TO_LSIZE_HI (size);
t2p->ctt_lsizelo = CTF_SIZE_TO_LSIZE_LO (size);
}
break;
}
v2size = get_ctt_size_v2 (fp, t2p, NULL, &v2increment);
v2bytes = get_vbytes_v2 (kind, v2size, vlen);
/* Catch out-of-sync get_ctt_size_*(). The count goes wrong if
these are not identical (and having them different makes no
sense semantically). */
assert (size == v2size);
/* Now the varlen info. */
vdata = (void *) ((uintptr_t) tp + increment);
v2data = (void *) ((uintptr_t) t2p + v2increment);
switch (kind)
{
case CTF_K_ARRAY:
{
const ctf_array_v1_t *ap = (const ctf_array_v1_t *) vdata;
ctf_array_t *a2p = (ctf_array_t *) v2data;
a2p->cta_contents = ap->cta_contents;
a2p->cta_index = ap->cta_index;
a2p->cta_nelems = ap->cta_nelems;
break;
}
case CTF_K_STRUCT:
case CTF_K_UNION:
{
ctf_member_t tmp;
const ctf_member_v1_t *m1 = (const ctf_member_v1_t *) vdata;
const ctf_lmember_v1_t *lm1 = (const ctf_lmember_v1_t *) m1;
ctf_member_t *m2 = (ctf_member_t *) v2data;
ctf_lmember_t *lm2 = (ctf_lmember_t *) m2;
unsigned long i;
/* We walk all four pointers forward, but only reference the two
that are valid for the given size, to avoid quadruplicating all
the code. */
for (i = vlen; i != 0; i--, m1++, lm1++, m2++, lm2++)
{
size_t offset;
if (size < CTF_LSTRUCT_THRESH_V1)
{
offset = m1->ctm_offset;
tmp.ctm_name = m1->ctm_name;
tmp.ctm_type = m1->ctm_type;
}
else
{
offset = CTF_LMEM_OFFSET (lm1);
tmp.ctm_name = lm1->ctlm_name;
tmp.ctm_type = lm1->ctlm_type;
}
if (size < CTF_LSTRUCT_THRESH)
{
m2->ctm_name = tmp.ctm_name;
m2->ctm_type = tmp.ctm_type;
m2->ctm_offset = offset;
}
else
{
lm2->ctlm_name = tmp.ctm_name;
lm2->ctlm_type = tmp.ctm_type;
lm2->ctlm_offsethi = CTF_OFFSET_TO_LMEMHI (offset);
lm2->ctlm_offsetlo = CTF_OFFSET_TO_LMEMLO (offset);
}
}
break;
}
case CTF_K_FUNCTION:
{
unsigned long i;
unsigned short *a1 = (unsigned short *) vdata;
uint32_t *a2 = (uint32_t *) v2data;
for (i = vlen; i != 0; i--, a1++, a2++)
*a2 = *a1;
}
/* FALLTHRU */
default:
/* Catch out-of-sync get_vbytes_*(). */
assert (vbytes == v2bytes);
memcpy (v2data, vdata, vbytes);
}
}
/* Verify that the entire region was converted. If not, we are either
converting too much, or too little (leading to a buffer overrun either here
or at read time, in init_types().) */
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
assert ((size_t) t2p - (size_t) fp->ctf_buf == cth->cth_stroff);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
ctf_set_version (fp, cth, CTF_VERSION_1_UPGRADED_3);
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free (old_ctf_base);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return 0;
}
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
/* Upgrade from any earlier version. */
static int
upgrade_types (ctf_file_t *fp, ctf_header_t *cth)
{
switch (cth->cth_version)
{
/* v1 requires a full pass and reformatting. */
case CTF_VERSION_1:
upgrade_types_v1 (fp, cth);
/* FALLTHRU */
/* Already-converted v1 is just like later versions except that its
parent/child boundary is unchanged (and much lower). */
case CTF_VERSION_1_UPGRADED_3:
fp->ctf_parmax = CTF_MAX_PTYPE_V1;
/* v2 is just the same as v3 except for new types and sections:
no upgrading required. */
case CTF_VERSION_2: ;
/* FALLTHRU */
}
return 0;
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
/* Initialize the type ID translation table with the byte offset of each type,
and initialize the hash tables of each named type. Upgrade the type table to
the latest supported representation in the process, if needed, and if this
recension of libctf supports upgrading. */
static int
init_types (ctf_file_t *fp, ctf_header_t *cth)
{
const ctf_type_t *tbuf;
const ctf_type_t *tend;
unsigned long pop[CTF_K_MAX + 1] = { 0 };
const ctf_type_t *tp;
uint32_t id, dst;
uint32_t *xp;
/* We determine whether the container is a child or a parent based on
the value of cth_parname. */
int child = cth->cth_parname != 0;
int nlstructs = 0, nlunions = 0;
int err;
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
assert (!(fp->ctf_flags & LCTF_RDWR));
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (_libctf_unlikely_ (fp->ctf_version == CTF_VERSION_1))
{
int err;
if ((err = upgrade_types (fp, cth)) != 0)
return err; /* Upgrade failed. */
}
tbuf = (ctf_type_t *) (fp->ctf_buf + cth->cth_typeoff);
tend = (ctf_type_t *) (fp->ctf_buf + cth->cth_stroff);
/* We make two passes through the entire type section. In this first
pass, we count the number of each type and the total number of types. */
for (tp = tbuf; tp < tend; fp->ctf_typemax++)
{
unsigned short kind = LCTF_INFO_KIND (fp, tp->ctt_info);
unsigned long vlen = LCTF_INFO_VLEN (fp, tp->ctt_info);
ssize_t size, increment, vbytes;
(void) ctf_get_ctt_size (fp, tp, &size, &increment);
vbytes = LCTF_VBYTES (fp, kind, size, vlen);
if (vbytes < 0)
return ECTF_CORRUPT;
if (kind == CTF_K_FORWARD)
{
/* For forward declarations, ctt_type is the CTF_K_* kind for the tag,
so bump that population count too. If ctt_type is unknown, treat
the tag as a struct. */
if (tp->ctt_type == CTF_K_UNKNOWN || tp->ctt_type >= CTF_K_MAX)
pop[CTF_K_STRUCT]++;
else
pop[tp->ctt_type]++;
}
tp = (ctf_type_t *) ((uintptr_t) tp + increment + vbytes);
pop[kind]++;
}
if (child)
{
ctf_dprintf ("CTF container %p is a child\n", (void *) fp);
fp->ctf_flags |= LCTF_CHILD;
}
else
ctf_dprintf ("CTF container %p is a parent\n", (void *) fp);
/* Now that we've counted up the number of each type, we can allocate
the hash tables, type translation table, and pointer table. */
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
if ((fp->ctf_structs.ctn_readonly
= ctf_hash_create (pop[CTF_K_STRUCT], ctf_hash_string,
ctf_hash_eq_string)) == NULL)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return ENOMEM;
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
if ((fp->ctf_unions.ctn_readonly
= ctf_hash_create (pop[CTF_K_UNION], ctf_hash_string,
ctf_hash_eq_string)) == NULL)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return ENOMEM;
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
if ((fp->ctf_enums.ctn_readonly
= ctf_hash_create (pop[CTF_K_ENUM], ctf_hash_string,
ctf_hash_eq_string)) == NULL)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return ENOMEM;
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
if ((fp->ctf_names.ctn_readonly
= ctf_hash_create (pop[CTF_K_INTEGER] +
pop[CTF_K_FLOAT] +
pop[CTF_K_FUNCTION] +
pop[CTF_K_TYPEDEF] +
pop[CTF_K_POINTER] +
pop[CTF_K_VOLATILE] +
pop[CTF_K_CONST] +
pop[CTF_K_RESTRICT],
ctf_hash_string,
ctf_hash_eq_string)) == NULL)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return ENOMEM;
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
fp->ctf_txlate = malloc (sizeof (uint32_t) * (fp->ctf_typemax + 1));
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
fp->ctf_ptrtab_len = fp->ctf_typemax + 1;
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
fp->ctf_ptrtab = malloc (sizeof (uint32_t) * fp->ctf_ptrtab_len);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (fp->ctf_txlate == NULL || fp->ctf_ptrtab == NULL)
return ENOMEM; /* Memory allocation failed. */
xp = fp->ctf_txlate;
*xp++ = 0; /* Type id 0 is used as a sentinel value. */
memset (fp->ctf_txlate, 0, sizeof (uint32_t) * (fp->ctf_typemax + 1));
memset (fp->ctf_ptrtab, 0, sizeof (uint32_t) * (fp->ctf_typemax + 1));
/* In the second pass through the types, we fill in each entry of the
type and pointer tables and add names to the appropriate hashes. */
for (id = 1, tp = tbuf; tp < tend; xp++, id++)
{
unsigned short kind = LCTF_INFO_KIND (fp, tp->ctt_info);
unsigned short flag = LCTF_INFO_ISROOT (fp, tp->ctt_info);
unsigned long vlen = LCTF_INFO_VLEN (fp, tp->ctt_info);
ssize_t size, increment, vbytes;
const char *name;
(void) ctf_get_ctt_size (fp, tp, &size, &increment);
name = ctf_strptr (fp, tp->ctt_name);
vbytes = LCTF_VBYTES (fp, kind, size, vlen);
switch (kind)
{
case CTF_K_INTEGER:
case CTF_K_FLOAT:
/* Names are reused by bit-fields, which are differentiated by their
encodings, and so typically we'd record only the first instance of
a given intrinsic. However, we replace an existing type with a
root-visible version so that we can be sure to find it when
checking for conflicting definitions in ctf_add_type(). */
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
if (((ctf_hash_lookup_type (fp->ctf_names.ctn_readonly,
fp, name)) == 0)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
|| (flag & CTF_ADD_ROOT))
{
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
err = ctf_hash_define_type (fp->ctf_names.ctn_readonly, fp,
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
LCTF_INDEX_TO_TYPE (fp, id, child),
tp->ctt_name);
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
if (err != 0)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return err;
}
break;
/* These kinds have no name, so do not need interning into any
hashtables. */
case CTF_K_ARRAY:
case CTF_K_SLICE:
break;
case CTF_K_FUNCTION:
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
err = ctf_hash_insert_type (fp->ctf_names.ctn_readonly, fp,
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
LCTF_INDEX_TO_TYPE (fp, id, child),
tp->ctt_name);
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
if (err != 0)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return err;
break;
case CTF_K_STRUCT:
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
err = ctf_hash_define_type (fp->ctf_structs.ctn_readonly, fp,
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
LCTF_INDEX_TO_TYPE (fp, id, child),
tp->ctt_name);
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
if (err != 0)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return err;
if (size >= CTF_LSTRUCT_THRESH)
nlstructs++;
break;
case CTF_K_UNION:
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
err = ctf_hash_define_type (fp->ctf_unions.ctn_readonly, fp,
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
LCTF_INDEX_TO_TYPE (fp, id, child),
tp->ctt_name);
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
if (err != 0)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return err;
if (size >= CTF_LSTRUCT_THRESH)
nlunions++;
break;
case CTF_K_ENUM:
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
err = ctf_hash_define_type (fp->ctf_enums.ctn_readonly, fp,
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
LCTF_INDEX_TO_TYPE (fp, id, child),
tp->ctt_name);
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
if (err != 0)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return err;
break;
case CTF_K_TYPEDEF:
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
err = ctf_hash_insert_type (fp->ctf_names.ctn_readonly, fp,
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
LCTF_INDEX_TO_TYPE (fp, id, child),
tp->ctt_name);
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
if (err != 0)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return err;
break;
case CTF_K_FORWARD:
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
{
ctf_names_t *np = ctf_name_table (fp, tp->ctt_type);
/* Only insert forward tags into the given hash if the type or tag
name is not already present. */
if (ctf_hash_lookup_type (np->ctn_readonly, fp, name) == 0)
{
err = ctf_hash_insert_type (np->ctn_readonly, fp,
LCTF_INDEX_TO_TYPE (fp, id, child),
tp->ctt_name);
if (err != 0)
return err;
}
break;
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
case CTF_K_POINTER:
/* If the type referenced by the pointer is in this CTF container,
then store the index of the pointer type in
fp->ctf_ptrtab[ index of referenced type ]. */
if (LCTF_TYPE_ISCHILD (fp, tp->ctt_type) == child
&& LCTF_TYPE_TO_INDEX (fp, tp->ctt_type) <= fp->ctf_typemax)
fp->ctf_ptrtab[LCTF_TYPE_TO_INDEX (fp, tp->ctt_type)] = id;
/*FALLTHRU*/
case CTF_K_VOLATILE:
case CTF_K_CONST:
case CTF_K_RESTRICT:
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
err = ctf_hash_insert_type (fp->ctf_names.ctn_readonly, fp,
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
LCTF_INDEX_TO_TYPE (fp, id, child),
tp->ctt_name);
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
if (err != 0)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return err;
break;
default:
ctf_dprintf ("unhandled CTF kind in endianness conversion -- %x\n",
kind);
return ECTF_CORRUPT;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
}
*xp = (uint32_t) ((uintptr_t) tp - (uintptr_t) fp->ctf_buf);
tp = (ctf_type_t *) ((uintptr_t) tp + increment + vbytes);
}
ctf_dprintf ("%lu total types processed\n", fp->ctf_typemax);
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
ctf_dprintf ("%u enum names hashed\n",
ctf_hash_size (fp->ctf_enums.ctn_readonly));
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
ctf_dprintf ("%u struct names hashed (%d long)\n",
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
ctf_hash_size (fp->ctf_structs.ctn_readonly), nlstructs);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
ctf_dprintf ("%u union names hashed (%d long)\n",
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
ctf_hash_size (fp->ctf_unions.ctn_readonly), nlunions);
ctf_dprintf ("%u base type names hashed\n",
ctf_hash_size (fp->ctf_names.ctn_readonly));
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
/* Make an additional pass through the pointer table to find pointers that
point to anonymous typedef nodes. If we find one, modify the pointer table
so that the pointer is also known to point to the node that is referenced
by the anonymous typedef node. */
for (id = 1; id <= fp->ctf_typemax; id++)
{
if ((dst = fp->ctf_ptrtab[id]) != 0)
{
tp = LCTF_INDEX_TO_TYPEPTR (fp, id);
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
if (LCTF_INFO_KIND (fp, tp->ctt_info) == CTF_K_TYPEDEF
&& strcmp (ctf_strptr (fp, tp->ctt_name), "") == 0
&& LCTF_TYPE_ISCHILD (fp, tp->ctt_type) == child
&& LCTF_TYPE_TO_INDEX (fp, tp->ctt_type) <= fp->ctf_typemax)
fp->ctf_ptrtab[LCTF_TYPE_TO_INDEX (fp, tp->ctt_type)] = dst;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
}
}
return 0;
}
/* Endianness-flipping routines.
We flip everything, mindlessly, even 1-byte entities, so that future
expansions do not require changes to this code. */
/* < C11? define away static assertions. */
#if !defined (__STDC_VERSION__) || __STDC_VERSION__ < 201112L
#define _Static_assert(cond, err)
#endif
/* Swap the endianness of something. */
#define swap_thing(x) \
do { \
_Static_assert (sizeof (x) == 1 || (sizeof (x) % 2 == 0 \
&& sizeof (x) <= 8), \
"Invalid size, update endianness code"); \
switch (sizeof (x)) { \
case 2: x = bswap_16 (x); break; \
case 4: x = bswap_32 (x); break; \
case 8: x = bswap_64 (x); break; \
case 1: /* Nothing needs doing */ \
break; \
} \
} while (0);
/* Flip the endianness of the CTF header. */
static void
flip_header (ctf_header_t *cth)
{
swap_thing (cth->cth_preamble.ctp_magic);
swap_thing (cth->cth_preamble.ctp_version);
swap_thing (cth->cth_preamble.ctp_flags);
swap_thing (cth->cth_parlabel);
swap_thing (cth->cth_parname);
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
swap_thing (cth->cth_cuname);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
swap_thing (cth->cth_objtoff);
swap_thing (cth->cth_funcoff);
swap_thing (cth->cth_objtidxoff);
swap_thing (cth->cth_funcidxoff);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
swap_thing (cth->cth_varoff);
swap_thing (cth->cth_typeoff);
swap_thing (cth->cth_stroff);
swap_thing (cth->cth_strlen);
}
/* Flip the endianness of the label section, an array of ctf_lblent_t. */
static void
flip_lbls (void *start, size_t len)
{
ctf_lblent_t *lbl = start;
ssize_t i;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
for (i = len / sizeof (struct ctf_lblent); i > 0; lbl++, i--)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
swap_thing (lbl->ctl_label);
swap_thing (lbl->ctl_type);
}
}
/* Flip the endianness of the data-object or function sections or their indexes,
all arrays of uint32_t. (The function section has more internal structure,
but that structure is an array of uint32_t, so can be treated as one big
array for byte-swapping.) */
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
static void
flip_objts (void *start, size_t len)
{
uint32_t *obj = start;
ssize_t i;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
for (i = len / sizeof (uint32_t); i > 0; obj++, i--)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
swap_thing (*obj);
}
/* Flip the endianness of the variable section, an array of ctf_varent_t. */
static void
flip_vars (void *start, size_t len)
{
ctf_varent_t *var = start;
ssize_t i;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
for (i = len / sizeof (struct ctf_varent); i > 0; var++, i--)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
swap_thing (var->ctv_name);
swap_thing (var->ctv_type);
}
}
/* Flip the endianness of the type section, a tagged array of ctf_type or
ctf_stype followed by variable data. */
static int
flip_types (void *start, size_t len)
{
ctf_type_t *t = start;
while ((uintptr_t) t < ((uintptr_t) start) + len)
{
swap_thing (t->ctt_name);
swap_thing (t->ctt_info);
swap_thing (t->ctt_size);
uint32_t kind = CTF_V2_INFO_KIND (t->ctt_info);
size_t size = t->ctt_size;
uint32_t vlen = CTF_V2_INFO_VLEN (t->ctt_info);
size_t vbytes = get_vbytes_v2 (kind, size, vlen);
if (_libctf_unlikely_ (size == CTF_LSIZE_SENT))
{
swap_thing (t->ctt_lsizehi);
swap_thing (t->ctt_lsizelo);
size = CTF_TYPE_LSIZE (t);
t = (ctf_type_t *) ((uintptr_t) t + sizeof (ctf_type_t));
}
else
t = (ctf_type_t *) ((uintptr_t) t + sizeof (ctf_stype_t));
switch (kind)
{
case CTF_K_FORWARD:
case CTF_K_UNKNOWN:
case CTF_K_POINTER:
case CTF_K_TYPEDEF:
case CTF_K_VOLATILE:
case CTF_K_CONST:
case CTF_K_RESTRICT:
/* These types have no vlen data to swap. */
assert (vbytes == 0);
break;
case CTF_K_INTEGER:
case CTF_K_FLOAT:
{
/* These types have a single uint32_t. */
uint32_t *item = (uint32_t *) t;
swap_thing (*item);
break;
}
case CTF_K_FUNCTION:
{
/* This type has a bunch of uint32_ts. */
uint32_t *item = (uint32_t *) t;
ssize_t i;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
for (i = vlen; i > 0; item++, i--)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
swap_thing (*item);
break;
}
case CTF_K_ARRAY:
{
/* This has a single ctf_array_t. */
ctf_array_t *a = (ctf_array_t *) t;
assert (vbytes == sizeof (ctf_array_t));
swap_thing (a->cta_contents);
swap_thing (a->cta_index);
swap_thing (a->cta_nelems);
break;
}
case CTF_K_SLICE:
{
/* This has a single ctf_slice_t. */
ctf_slice_t *s = (ctf_slice_t *) t;
assert (vbytes == sizeof (ctf_slice_t));
swap_thing (s->cts_type);
swap_thing (s->cts_offset);
swap_thing (s->cts_bits);
break;
}
case CTF_K_STRUCT:
case CTF_K_UNION:
{
/* This has an array of ctf_member or ctf_lmember, depending on
size. We could consider it to be a simple array of uint32_t,
but for safety's sake in case these structures ever acquire
non-uint32_t members, do it member by member. */
if (_libctf_unlikely_ (size >= CTF_LSTRUCT_THRESH))
{
ctf_lmember_t *lm = (ctf_lmember_t *) t;
ssize_t i;
for (i = vlen; i > 0; i--, lm++)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
swap_thing (lm->ctlm_name);
swap_thing (lm->ctlm_offsethi);
swap_thing (lm->ctlm_type);
swap_thing (lm->ctlm_offsetlo);
}
}
else
{
ctf_member_t *m = (ctf_member_t *) t;
ssize_t i;
for (i = vlen; i > 0; i--, m++)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
swap_thing (m->ctm_name);
swap_thing (m->ctm_offset);
swap_thing (m->ctm_type);
}
}
break;
}
case CTF_K_ENUM:
{
/* This has an array of ctf_enum_t. */
ctf_enum_t *item = (ctf_enum_t *) t;
ssize_t i;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
for (i = vlen; i > 0; item++, i--)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
swap_thing (item->cte_name);
swap_thing (item->cte_value);
}
break;
}
default:
ctf_dprintf ("unhandled CTF kind in endianness conversion -- %x\n",
kind);
return ECTF_CORRUPT;
}
t = (ctf_type_t *) ((uintptr_t) t + vbytes);
}
return 0;
}
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
/* Flip the endianness of BUF, given the offsets in the (already endian-
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
converted) CTH.
All of this stuff happens before the header is fully initialized, so the
LCTF_*() macros cannot be used yet. Since we do not try to endian-convert v1
data, this is no real loss. */
static int
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
flip_ctf (ctf_header_t *cth, unsigned char *buf)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
flip_lbls (buf + cth->cth_lbloff, cth->cth_objtoff - cth->cth_lbloff);
flip_objts (buf + cth->cth_objtoff, cth->cth_funcoff - cth->cth_objtoff);
flip_objts (buf + cth->cth_funcoff, cth->cth_objtidxoff - cth->cth_funcoff);
flip_objts (buf + cth->cth_objtidxoff, cth->cth_funcidxoff - cth->cth_objtidxoff);
flip_objts (buf + cth->cth_funcidxoff, cth->cth_varoff - cth->cth_funcidxoff);
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
flip_vars (buf + cth->cth_varoff, cth->cth_typeoff - cth->cth_varoff);
return flip_types (buf + cth->cth_typeoff, cth->cth_stroff - cth->cth_typeoff);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
}
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
/* Set up the ctl hashes in a ctf_file_t. Called by both writable and
non-writable dictionary initialization. */
void ctf_set_ctl_hashes (ctf_file_t *fp)
{
/* Initialize the ctf_lookup_by_name top-level dictionary. We keep an
array of type name prefixes and the corresponding ctf_hash to use. */
fp->ctf_lookups[0].ctl_prefix = "struct";
fp->ctf_lookups[0].ctl_len = strlen (fp->ctf_lookups[0].ctl_prefix);
fp->ctf_lookups[0].ctl_hash = &fp->ctf_structs;
fp->ctf_lookups[1].ctl_prefix = "union";
fp->ctf_lookups[1].ctl_len = strlen (fp->ctf_lookups[1].ctl_prefix);
fp->ctf_lookups[1].ctl_hash = &fp->ctf_unions;
fp->ctf_lookups[2].ctl_prefix = "enum";
fp->ctf_lookups[2].ctl_len = strlen (fp->ctf_lookups[2].ctl_prefix);
fp->ctf_lookups[2].ctl_hash = &fp->ctf_enums;
fp->ctf_lookups[3].ctl_prefix = _CTF_NULLSTR;
fp->ctf_lookups[3].ctl_len = strlen (fp->ctf_lookups[3].ctl_prefix);
fp->ctf_lookups[3].ctl_hash = &fp->ctf_names;
fp->ctf_lookups[4].ctl_prefix = NULL;
fp->ctf_lookups[4].ctl_len = 0;
fp->ctf_lookups[4].ctl_hash = NULL;
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
/* Open a CTF file, mocking up a suitable ctf_sect. */
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
ctf_file_t *ctf_simple_open (const char *ctfsect, size_t ctfsect_size,
const char *symsect, size_t symsect_size,
size_t symsect_entsize,
const char *strsect, size_t strsect_size,
int *errp)
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
{
return ctf_simple_open_internal (ctfsect, ctfsect_size, symsect, symsect_size,
symsect_entsize, strsect, strsect_size, NULL,
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
0, errp);
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
}
/* Open a CTF file, mocking up a suitable ctf_sect and overriding the external
strtab with a synthetic one. */
ctf_file_t *ctf_simple_open_internal (const char *ctfsect, size_t ctfsect_size,
const char *symsect, size_t symsect_size,
size_t symsect_entsize,
const char *strsect, size_t strsect_size,
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
ctf_dynhash_t *syn_strtab, int writable,
int *errp)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
ctf_sect_t skeleton;
ctf_sect_t ctf_sect, sym_sect, str_sect;
ctf_sect_t *ctfsectp = NULL;
ctf_sect_t *symsectp = NULL;
ctf_sect_t *strsectp = NULL;
skeleton.cts_name = _CTF_SECTION;
skeleton.cts_entsize = 1;
if (ctfsect)
{
memcpy (&ctf_sect, &skeleton, sizeof (struct ctf_sect));
ctf_sect.cts_data = ctfsect;
ctf_sect.cts_size = ctfsect_size;
ctfsectp = &ctf_sect;
}
if (symsect)
{
memcpy (&sym_sect, &skeleton, sizeof (struct ctf_sect));
sym_sect.cts_data = symsect;
sym_sect.cts_size = symsect_size;
sym_sect.cts_entsize = symsect_entsize;
symsectp = &sym_sect;
}
if (strsect)
{
memcpy (&str_sect, &skeleton, sizeof (struct ctf_sect));
str_sect.cts_data = strsect;
str_sect.cts_size = strsect_size;
strsectp = &str_sect;
}
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
return ctf_bufopen_internal (ctfsectp, symsectp, strsectp, syn_strtab,
writable, errp);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
}
/* Decode the specified CTF buffer and optional symbol table, and create a new
CTF container representing the symbolic debugging information. This code can
be used directly by the debugger, or it can be used as the engine for
ctf_fdopen() or ctf_open(), below. */
ctf_file_t *
ctf_bufopen (const ctf_sect_t *ctfsect, const ctf_sect_t *symsect,
const ctf_sect_t *strsect, int *errp)
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
{
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
return ctf_bufopen_internal (ctfsect, symsect, strsect, NULL, 0, errp);
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
}
/* Like ctf_bufopen, but overriding the external strtab with a synthetic one. */
ctf_file_t *
ctf_bufopen_internal (const ctf_sect_t *ctfsect, const ctf_sect_t *symsect,
const ctf_sect_t *strsect, ctf_dynhash_t *syn_strtab,
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
int writable, int *errp)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
const ctf_preamble_t *pp;
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
size_t hdrsz = sizeof (ctf_header_t);
ctf_header_t *hp;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
ctf_file_t *fp;
int foreign_endian = 0;
int err;
libctf_init_debug();
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
if ((ctfsect == NULL) || ((symsect != NULL) &&
((strsect == NULL) && syn_strtab == NULL)))
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return (ctf_set_open_errno (errp, EINVAL));
if (symsect != NULL && symsect->cts_entsize != sizeof (Elf32_Sym) &&
symsect->cts_entsize != sizeof (Elf64_Sym))
return (ctf_set_open_errno (errp, ECTF_SYMTAB));
if (symsect != NULL && symsect->cts_data == NULL)
return (ctf_set_open_errno (errp, ECTF_SYMBAD));
if (strsect != NULL && strsect->cts_data == NULL)
return (ctf_set_open_errno (errp, ECTF_STRBAD));
if (ctfsect->cts_size < sizeof (ctf_preamble_t))
return (ctf_set_open_errno (errp, ECTF_NOCTFBUF));
pp = (const ctf_preamble_t *) ctfsect->cts_data;
ctf_dprintf ("ctf_bufopen: magic=0x%x version=%u\n",
pp->ctp_magic, pp->ctp_version);
/* Validate each part of the CTF header.
First, we validate the preamble (common to all versions). At that point,
we know the endianness and specific header version, and can validate the
version-specific parts including section offsets and alignments.
We specifically do not support foreign-endian old versions. */
if (_libctf_unlikely_ (pp->ctp_magic != CTF_MAGIC))
{
if (pp->ctp_magic == bswap_16 (CTF_MAGIC))
{
if (pp->ctp_version != CTF_VERSION_3)
return (ctf_set_open_errno (errp, ECTF_CTFVERS));
foreign_endian = 1;
}
else
return (ctf_set_open_errno (errp, ECTF_NOCTFBUF));
}
if (_libctf_unlikely_ ((pp->ctp_version < CTF_VERSION_1)
|| (pp->ctp_version > CTF_VERSION_3)))
return (ctf_set_open_errno (errp, ECTF_CTFVERS));
if ((symsect != NULL) && (pp->ctp_version < CTF_VERSION_2))
{
/* The symtab can contain function entries which contain embedded ctf
info. We do not support dynamically upgrading such entries (none
should exist in any case, since dwarf2ctf does not create them). */
ctf_dprintf ("ctf_bufopen: CTF version %d symsect not "
"supported\n", pp->ctp_version);
return (ctf_set_open_errno (errp, ECTF_NOTSUP));
}
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if (pp->ctp_version < CTF_VERSION_3)
hdrsz = sizeof (ctf_header_v2_t);
if (ctfsect->cts_size < hdrsz)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return (ctf_set_open_errno (errp, ECTF_NOCTFBUF));
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
if ((fp = malloc (sizeof (ctf_file_t))) == NULL)
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
return (ctf_set_open_errno (errp, ENOMEM));
memset (fp, 0, sizeof (ctf_file_t));
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
if (writable)
fp->ctf_flags |= LCTF_RDWR;
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
if ((fp->ctf_header = malloc (sizeof (struct ctf_header))) == NULL)
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
{
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free (fp);
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
return (ctf_set_open_errno (errp, ENOMEM));
}
hp = fp->ctf_header;
memcpy (hp, ctfsect->cts_data, hdrsz);
if (pp->ctp_version < CTF_VERSION_3)
upgrade_header (hp);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (foreign_endian)
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
flip_header (hp);
fp->ctf_openflags = hp->cth_flags;
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
fp->ctf_size = hp->cth_stroff + hp->cth_strlen;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
ctf_dprintf ("ctf_bufopen: uncompressed size=%lu\n",
(unsigned long) fp->ctf_size);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if (hp->cth_lbloff > fp->ctf_size || hp->cth_objtoff > fp->ctf_size
|| hp->cth_funcoff > fp->ctf_size || hp->cth_objtidxoff > fp->ctf_size
|| hp->cth_funcidxoff > fp->ctf_size || hp->cth_typeoff > fp->ctf_size
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
|| hp->cth_stroff > fp->ctf_size)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return (ctf_set_open_errno (errp, ECTF_CORRUPT));
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if (hp->cth_lbloff > hp->cth_objtoff
|| hp->cth_objtoff > hp->cth_funcoff
|| hp->cth_funcoff > hp->cth_typeoff
|| hp->cth_funcoff > hp->cth_objtidxoff
|| hp->cth_objtidxoff > hp->cth_funcidxoff
|| hp->cth_funcidxoff > hp->cth_varoff
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
|| hp->cth_varoff > hp->cth_typeoff || hp->cth_typeoff > hp->cth_stroff)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return (ctf_set_open_errno (errp, ECTF_CORRUPT));
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if ((hp->cth_lbloff & 3) || (hp->cth_objtoff & 2)
|| (hp->cth_funcoff & 2) || (hp->cth_objtidxoff & 2)
|| (hp->cth_funcidxoff & 2) || (hp->cth_varoff & 3)
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
|| (hp->cth_typeoff & 3))
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
return (ctf_set_open_errno (errp, ECTF_CORRUPT));
/* Once everything is determined to be valid, attempt to decompress the CTF
data buffer if it is compressed, or copy it into new storage if it is not
compressed but needs endian-flipping. Otherwise we just put the data
section's buffer pointer into ctf_buf, below. */
/* Note: if this is a v1 buffer, it will be reallocated and expanded by
init_types(). */
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if (hp->cth_flags & CTF_F_COMPRESS)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
libctf: fix a number of build problems found on Solaris and NetBSD - Use of nonportable <endian.h> - Use of qsort_r - Use of zlib without appropriate magic to pull in the binutils zlib - Use of off64_t without checking (fixed by dropping the unused fields that need off64_t entirely) - signedness problems due to long being too short a type on 32-bit platforms: ctf_id_t is now 'unsigned long', and CTF_ERR must be used only for functions that return ctf_id_t - One lingering use of bzero() and of <sys/errno.h> All fixed, using code from gnulib where possible. Relatedly, set cts_size in a couple of places it was missed (string table and symbol table loading upon ctf_bfdopen()). binutils/ * objdump.c (make_ctfsect): Drop cts_type, cts_flags, and cts_offset. * readelf.c (shdr_to_ctf_sect): Likewise. include/ * ctf-api.h (ctf_sect_t): Drop cts_type, cts_flags, and cts_offset. (ctf_id_t): This is now an unsigned type. (CTF_ERR): Cast it to ctf_id_t. Note that it should only be used for ctf_id_t-returning functions. libctf/ * Makefile.am (ZLIB): New. (ZLIBINC): Likewise. (AM_CFLAGS): Use them. (libctf_a_LIBADD): New, for LIBOBJS. * configure.ac: Check for zlib, endian.h, and qsort_r. * ctf-endian.h: New, providing htole64 and le64toh. * swap.h: Code style fixes. (bswap_identity_64): New. * qsort_r.c: New, from gnulib (with one added #include). * ctf-decls.h: New, providing a conditional qsort_r declaration, and unconditional definitions of MIN and MAX. * ctf-impl.h: Use it. Do not use <sys/errno.h>. (ctf_set_errno): Now returns unsigned long. * ctf-util.c (ctf_set_errno): Adjust here too. * ctf-archive.c: Use ctf-endian.h. (ctf_arc_open_by_offset): Use memset, not bzero. Drop cts_type, cts_flags and cts_offset. (ctf_arc_write): Drop debugging dependent on the size of off_t. * ctf-create.c: Provide a definition of roundup if not defined. (ctf_create): Drop cts_type, cts_flags and cts_offset. (ctf_add_reftype): Do not check if type IDs are below zero. (ctf_add_slice): Likewise. (ctf_add_typedef): Likewise. (ctf_add_member_offset): Cast error-returning ssize_t's to size_t when known error-free. Drop CTF_ERR usage for functions returning int. (ctf_add_member_encoded): Drop CTF_ERR usage for functions returning int. (ctf_add_variable): Likewise. (enumcmp): Likewise. (enumadd): Likewise. (membcmp): Likewise. (ctf_add_type): Likewise. Cast error-returning ssize_t's to size_t when known error-free. * ctf-dump.c (ctf_is_slice): Drop CTF_ERR usage for functions returning int: use CTF_ERR for functions returning ctf_type_id. (ctf_dump_label): Likewise. (ctf_dump_objts): Likewise. * ctf-labels.c (ctf_label_topmost): Likewise. (ctf_label_iter): Likewise. (ctf_label_info): Likewise. * ctf-lookup.c (ctf_func_args): Likewise. * ctf-open.c (upgrade_types): Cast to size_t where appropriate. (ctf_bufopen): Likewise. Use zlib types as needed. * ctf-types.c (ctf_member_iter): Drop CTF_ERR usage for functions returning int. (ctf_enum_iter): Likewise. (ctf_type_size): Likewise. (ctf_type_align): Likewise. Cast to size_t where appropriate. (ctf_type_kind_unsliced): Likewise. (ctf_type_kind): Likewise. (ctf_type_encoding): Likewise. (ctf_member_info): Likewise. (ctf_array_info): Likewise. (ctf_enum_value): Likewise. (ctf_type_rvisit): Likewise. * ctf-open-bfd.c (ctf_bfdopen): Drop cts_type, cts_flags and cts_offset. (ctf_simple_open): Likewise. (ctf_bfdopen_ctfsect): Likewise. Set cts_size properly. * Makefile.in: Regenerate. * aclocal.m4: Likewise. * config.h: Likewise. * configure: Likewise.
2019-05-31 17:10:51 +08:00
size_t srclen;
uLongf dstlen;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
const void *src;
int rc = Z_OK;
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
/* We are allocating this ourselves, so we can drop the ctf header
copy in favour of ctf->ctf_header. */
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
if ((fp->ctf_base = malloc (fp->ctf_size)) == NULL)
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
{
err = ECTF_ZALLOC;
goto bad;
}
fp->ctf_dynbase = fp->ctf_base;
hp->cth_flags &= ~CTF_F_COMPRESS;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
src = (unsigned char *) ctfsect->cts_data + hdrsz;
srclen = ctfsect->cts_size - hdrsz;
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
dstlen = fp->ctf_size;
fp->ctf_buf = fp->ctf_base;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if ((rc = uncompress (fp->ctf_base, &dstlen, src, srclen)) != Z_OK)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
ctf_dprintf ("zlib inflate err: %s\n", zError (rc));
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
err = ECTF_DECOMPRESS;
goto bad;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
}
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if ((size_t) dstlen != fp->ctf_size)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
ctf_dprintf ("zlib inflate short -- got %lu of %lu "
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
"bytes\n", (unsigned long) dstlen,
(unsigned long) fp->ctf_size);
err = ECTF_CORRUPT;
goto bad;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
}
}
else if (foreign_endian)
{
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
if ((fp->ctf_base = malloc (fp->ctf_size)) == NULL)
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
{
err = ECTF_ZALLOC;
goto bad;
}
fp->ctf_dynbase = fp->ctf_base;
memcpy (fp->ctf_base, ((unsigned char *) ctfsect->cts_data) + hdrsz,
fp->ctf_size);
fp->ctf_buf = fp->ctf_base;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
}
else
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
{
/* We are just using the section passed in -- but its header may be an old
version. Point ctf_buf past the old header, and never touch it
again. */
fp->ctf_base = (unsigned char *) ctfsect->cts_data;
fp->ctf_dynbase = NULL;
fp->ctf_buf = fp->ctf_base + hdrsz;
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
/* Once we have uncompressed and validated the CTF data buffer, we can
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
proceed with initializing the ctf_file_t we allocated above.
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
Nothing that depends on buf or base should be set directly in this function
before the init_types() call, because it may be reallocated during
transparent upgrade if this recension of libctf is so configured: see
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
ctf_set_base(). */
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
ctf_set_version (fp, hp, hp->cth_version);
libctf: deduplicate and sort the string table ctf.h states: > [...] the CTF string table does not contain any duplicated strings. Unfortunately this is entirely untrue: libctf has before now made no attempt whatsoever to deduplicate the string table. It computes the string table's length on the fly as it adds new strings to the dynamic CTF file, and ctf_update() just writes each string to the table and notes the current write position as it traverses the dynamic CTF file's data structures and builds the final CTF buffer. There is no global view of the strings and no deduplication. Fix this by erasing the ctf_dtvstrlen dead-reckoning length, and adding a new dynhash table ctf_str_atoms that maps unique strings to a list of references to those strings: a reference is a simple uint32_t * to some value somewhere in the under-construction CTF buffer that needs updating to note the string offset when the strtab is laid out. Adding a string is now a simple matter of calling ctf_str_add_ref(), which adds a new atom to the atoms table, if one doesn't already exist, and adding the location of the reference to this atom to the refs list attached to the atom: this works reliably as long as one takes care to only call ctf_str_add_ref() once the final location of the offset is known (so you can't call it on a temporary structure and then memcpy() that structure into place in the CTF buffer, because the ref will still point to the old location: ctf_update() changes accordingly). Generating the CTF string table is a matter of calling ctf_str_write_strtab(), which counts the length and number of elements in the atoms table using the ctf_dynhash_iter() function we just added, populating an array of pointers into the atoms table and sorting it into order (to help compressors), then traversing this table and emitting it, updating the refs to each atom as we go. The only complexity here is arranging to keep the null string at offset zero, since a lot of code in libctf depends on being able to leave strtab references at 0 to indicate 'no name'. Once the table is constructed and the refs updated, we know how long it is, so we can realloc() the partial CTF buffer we allocated earlier and can copy the table on to the end of it (and purge the refs because they're not needed any more and have been invalidated by the realloc() call in any case). The net effect of all this is a reduction in uncompressed strtab sizes of about 30% (perhaps a quarter to a half of all strings across the Linux kernel are eliminated as duplicates). Of course, duplicated strings are highly redundant, so the space saving after compression is only about 20%: when the other non-strtab sections are factored in, CTF sizes shrink by about 10%. No change in externally-visible API or file format (other than the reduction in pointless redundancy). libctf/ * ctf-impl.h: (struct ctf_strs_writable): New, non-const version of struct ctf_strs. (struct ctf_dtdef): Note that dtd_data.ctt_name is unpopulated. (struct ctf_str_atom): New, disambiguated single string. (struct ctf_str_atom_ref): New, points to some other location that references this string's offset. (struct ctf_file): New members ctf_str_atoms and ctf_str_num_refs. Remove member ctf_dtvstrlen: we no longer track the total strlen as we add strings. (ctf_str_create_atoms): Declare new function in ctf-string.c. (ctf_str_free_atoms): Likewise. (ctf_str_add): Likewise. (ctf_str_add_ref): Likewise. (ctf_str_purge_refs): Likewise. (ctf_str_write_strtab): Likewise. (ctf_realloc): Declare new function in ctf-util.c. * ctf-open.c (ctf_bufopen): Create the atoms table. (ctf_file_close): Destroy it. * ctf-create.c (ctf_update): Copy-and-free it on update. No longer special-case the position of the parname string. Construct the strtab by calling ctf_str_add_ref and ctf_str_write_strtab after the rest of each buffer element is constructed, not via open-coding: realloc the CTF buffer and append the strtab to it. No longer maintain ctf_dtvstrlen. Sort the variable entry table later, after strtab construction. (ctf_copy_membnames): Remove: integrated into ctf_copy_{s,l,e}members. (ctf_copy_smembers): Drop the string offset: call ctf_str_add_ref after buffer element construction instead. (ctf_copy_lmembers): Likewise. (ctf_copy_emembers): Likewise. (ctf_create): No longer maintain the ctf_dtvstrlen. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. * ctf-util.c (ctf_realloc): New, wrapper around realloc that aborts if there are active ctf_str_num_refs. (ctf_strraw): Move to ctf-string.c. (ctf_strptr): Likewise. * ctf-string.c: New file, strtab manipulation. * Makefile.am (libctf_a_SOURCES): Add it. * Makefile.in: Regenerate.
2019-06-27 20:51:10 +08:00
ctf_str_create_atoms (fp);
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
fp->ctf_parmax = CTF_MAX_PTYPE;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
memcpy (&fp->ctf_data, ctfsect, sizeof (ctf_sect_t));
if (symsect != NULL)
{
memcpy (&fp->ctf_symtab, symsect, sizeof (ctf_sect_t));
memcpy (&fp->ctf_strtab, strsect, sizeof (ctf_sect_t));
}
if (fp->ctf_data.cts_name != NULL)
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
if ((fp->ctf_data.cts_name = strdup (fp->ctf_data.cts_name)) == NULL)
{
err = ENOMEM;
goto bad;
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (fp->ctf_symtab.cts_name != NULL)
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
if ((fp->ctf_symtab.cts_name = strdup (fp->ctf_symtab.cts_name)) == NULL)
{
err = ENOMEM;
goto bad;
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (fp->ctf_strtab.cts_name != NULL)
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
if ((fp->ctf_strtab.cts_name = strdup (fp->ctf_strtab.cts_name)) == NULL)
{
err = ENOMEM;
goto bad;
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (fp->ctf_data.cts_name == NULL)
fp->ctf_data.cts_name = _CTF_NULLSTR;
if (fp->ctf_symtab.cts_name == NULL)
fp->ctf_symtab.cts_name = _CTF_NULLSTR;
if (fp->ctf_strtab.cts_name == NULL)
fp->ctf_strtab.cts_name = _CTF_NULLSTR;
if (strsect != NULL)
{
fp->ctf_str[CTF_STRTAB_1].cts_strs = strsect->cts_data;
fp->ctf_str[CTF_STRTAB_1].cts_len = strsect->cts_size;
}
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
fp->ctf_syn_ext_strtab = syn_strtab;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (foreign_endian &&
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
(err = flip_ctf (hp, fp->ctf_buf)) != 0)
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
{
/* We can be certain that flip_ctf() will have endian-flipped everything
other than the types table when we return. In particular the header
is fine, so set it, to allow freeing to use the usual code path. */
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
ctf_set_base (fp, hp, fp->ctf_base);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
goto bad;
}
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
ctf_set_base (fp, hp, fp->ctf_base);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
/* No need to do anything else for dynamic containers: they do not support
symbol lookups, and the type table is maintained in the dthashes. */
if (fp->ctf_flags & LCTF_RDWR)
{
fp->ctf_refcnt = 1;
return fp;
}
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if ((err = init_types (fp, hp)) != 0)
goto bad;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
/* If we have a symbol table section, allocate and initialize
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
the symtab translation table, pointed to by ctf_sxlate. This table may be
too large for the actual size of the object and function info sections: if
so, ctf_nsyms will be adjusted and the excess will never be used. */
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (symsect != NULL)
{
fp->ctf_nsyms = symsect->cts_size / symsect->cts_entsize;
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
fp->ctf_sxlate = malloc (fp->ctf_nsyms * sizeof (uint32_t));
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (fp->ctf_sxlate == NULL)
{
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
err = ENOMEM;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
goto bad;
}
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if ((err = init_symtab (fp, hp, symsect, strsect)) != 0)
goto bad;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
}
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
ctf_set_ctl_hashes (fp);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (symsect != NULL)
{
if (symsect->cts_entsize == sizeof (Elf64_Sym))
(void) ctf_setmodel (fp, CTF_MODEL_LP64);
else
(void) ctf_setmodel (fp, CTF_MODEL_ILP32);
}
else
(void) ctf_setmodel (fp, CTF_MODEL_NATIVE);
fp->ctf_refcnt = 1;
return fp;
bad:
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
ctf_set_open_errno (errp, err);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
ctf_file_close (fp);
return NULL;
}
/* Close the specified CTF container and free associated data structures. Note
that ctf_file_close() is a reference counted operation: if the specified file
is the parent of other active containers, its reference count will be greater
than one and it will be freed later when no active children exist. */
void
ctf_file_close (ctf_file_t *fp)
{
ctf_dtdef_t *dtd, *ntd;
ctf_dvdef_t *dvd, *nvd;
if (fp == NULL)
return; /* Allow ctf_file_close(NULL) to simplify caller code. */
ctf_dprintf ("ctf_file_close(%p) refcnt=%u\n", (void *) fp, fp->ctf_refcnt);
if (fp->ctf_refcnt > 1)
{
fp->ctf_refcnt--;
return;
}
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free (fp->ctf_dyncuname);
free (fp->ctf_dynparname);
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
ctf_file_close (fp->ctf_parent);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
for (dtd = ctf_list_next (&fp->ctf_dtdefs); dtd != NULL; dtd = ntd)
{
ntd = ctf_list_next (dtd);
ctf_dtd_delete (fp, dtd);
}
ctf_dynhash_destroy (fp->ctf_dthash);
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
if (fp->ctf_flags & LCTF_RDWR)
{
ctf_dynhash_destroy (fp->ctf_structs.ctn_writable);
ctf_dynhash_destroy (fp->ctf_unions.ctn_writable);
ctf_dynhash_destroy (fp->ctf_enums.ctn_writable);
ctf_dynhash_destroy (fp->ctf_names.ctn_writable);
}
else
{
ctf_hash_destroy (fp->ctf_structs.ctn_readonly);
ctf_hash_destroy (fp->ctf_unions.ctn_readonly);
ctf_hash_destroy (fp->ctf_enums.ctn_readonly);
ctf_hash_destroy (fp->ctf_names.ctn_readonly);
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
for (dvd = ctf_list_next (&fp->ctf_dvdefs); dvd != NULL; dvd = nvd)
{
nvd = ctf_list_next (dvd);
ctf_dvd_delete (fp, dvd);
}
ctf_dynhash_destroy (fp->ctf_dvhash);
libctf: deduplicate and sort the string table ctf.h states: > [...] the CTF string table does not contain any duplicated strings. Unfortunately this is entirely untrue: libctf has before now made no attempt whatsoever to deduplicate the string table. It computes the string table's length on the fly as it adds new strings to the dynamic CTF file, and ctf_update() just writes each string to the table and notes the current write position as it traverses the dynamic CTF file's data structures and builds the final CTF buffer. There is no global view of the strings and no deduplication. Fix this by erasing the ctf_dtvstrlen dead-reckoning length, and adding a new dynhash table ctf_str_atoms that maps unique strings to a list of references to those strings: a reference is a simple uint32_t * to some value somewhere in the under-construction CTF buffer that needs updating to note the string offset when the strtab is laid out. Adding a string is now a simple matter of calling ctf_str_add_ref(), which adds a new atom to the atoms table, if one doesn't already exist, and adding the location of the reference to this atom to the refs list attached to the atom: this works reliably as long as one takes care to only call ctf_str_add_ref() once the final location of the offset is known (so you can't call it on a temporary structure and then memcpy() that structure into place in the CTF buffer, because the ref will still point to the old location: ctf_update() changes accordingly). Generating the CTF string table is a matter of calling ctf_str_write_strtab(), which counts the length and number of elements in the atoms table using the ctf_dynhash_iter() function we just added, populating an array of pointers into the atoms table and sorting it into order (to help compressors), then traversing this table and emitting it, updating the refs to each atom as we go. The only complexity here is arranging to keep the null string at offset zero, since a lot of code in libctf depends on being able to leave strtab references at 0 to indicate 'no name'. Once the table is constructed and the refs updated, we know how long it is, so we can realloc() the partial CTF buffer we allocated earlier and can copy the table on to the end of it (and purge the refs because they're not needed any more and have been invalidated by the realloc() call in any case). The net effect of all this is a reduction in uncompressed strtab sizes of about 30% (perhaps a quarter to a half of all strings across the Linux kernel are eliminated as duplicates). Of course, duplicated strings are highly redundant, so the space saving after compression is only about 20%: when the other non-strtab sections are factored in, CTF sizes shrink by about 10%. No change in externally-visible API or file format (other than the reduction in pointless redundancy). libctf/ * ctf-impl.h: (struct ctf_strs_writable): New, non-const version of struct ctf_strs. (struct ctf_dtdef): Note that dtd_data.ctt_name is unpopulated. (struct ctf_str_atom): New, disambiguated single string. (struct ctf_str_atom_ref): New, points to some other location that references this string's offset. (struct ctf_file): New members ctf_str_atoms and ctf_str_num_refs. Remove member ctf_dtvstrlen: we no longer track the total strlen as we add strings. (ctf_str_create_atoms): Declare new function in ctf-string.c. (ctf_str_free_atoms): Likewise. (ctf_str_add): Likewise. (ctf_str_add_ref): Likewise. (ctf_str_purge_refs): Likewise. (ctf_str_write_strtab): Likewise. (ctf_realloc): Declare new function in ctf-util.c. * ctf-open.c (ctf_bufopen): Create the atoms table. (ctf_file_close): Destroy it. * ctf-create.c (ctf_update): Copy-and-free it on update. No longer special-case the position of the parname string. Construct the strtab by calling ctf_str_add_ref and ctf_str_write_strtab after the rest of each buffer element is constructed, not via open-coding: realloc the CTF buffer and append the strtab to it. No longer maintain ctf_dtvstrlen. Sort the variable entry table later, after strtab construction. (ctf_copy_membnames): Remove: integrated into ctf_copy_{s,l,e}members. (ctf_copy_smembers): Drop the string offset: call ctf_str_add_ref after buffer element construction instead. (ctf_copy_lmembers): Likewise. (ctf_copy_emembers): Likewise. (ctf_create): No longer maintain the ctf_dtvstrlen. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. * ctf-util.c (ctf_realloc): New, wrapper around realloc that aborts if there are active ctf_str_num_refs. (ctf_strraw): Move to ctf-string.c. (ctf_strptr): Likewise. * ctf-string.c: New file, strtab manipulation. * Makefile.am (libctf_a_SOURCES): Add it. * Makefile.in: Regenerate.
2019-06-27 20:51:10 +08:00
ctf_str_free_atoms (fp);
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free (fp->ctf_tmp_typeslice);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if (fp->ctf_data.cts_name != _CTF_NULLSTR)
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free ((char *) fp->ctf_data.cts_name);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if (fp->ctf_symtab.cts_name != _CTF_NULLSTR)
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free ((char *) fp->ctf_symtab.cts_name);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
if (fp->ctf_strtab.cts_name != _CTF_NULLSTR)
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free ((char *) fp->ctf_strtab.cts_name);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
else if (fp->ctf_data_mmapped)
ctf_munmap (fp->ctf_data_mmapped, fp->ctf_data_mmapped_len);
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free (fp->ctf_dynbase);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
ctf_dynhash_destroy (fp->ctf_syn_ext_strtab);
libctf: add the ctf_link machinery This is the start of work on the core of the linking mechanism for CTF sections. This commit handles the type and string sections. The linker calls these functions in sequence: ctf_link_add_ctf: to add each CTF section in the input in turn to a newly-created ctf_file_t (which will appear in the output, and which itself will become the shared parent that contains types that all TUs have in common (in all link modes) and all types that do not have conflicting definitions between types (by default). Input files that are themselves products of ld -r are supported, though this is not heavily tested yet. ctf_link: called once all input files are added to merge the types in all the input containers into the output container, eliminating duplicates. ctf_link_add_strtab: called once the ELF string table is finalized and all its offsets are known, this calls a callback provided by the linker which returns the string content and offset of every string in the ELF strtab in turn: all these strings which appear in the input CTF strtab are eliminated from it in favour of the ELF strtab: equally, any strings that only appear in the input strtab will reappear in the internal CTF strtab of the output. ctf_link_shuffle_syms (not yet implemented): called once the ELF symtab is finalized, this calls a callback provided by the linker which returns information on every symbol in turn as a ctf_link_sym_t. This is then used to shuffle the function info and data object sections in the CTF section into symbol table order, eliminating the index sections which map those sections to symbol names before that point. Currently just returns ECTF_NOTYET. ctf_link_write: Returns a buffer containing either a serialized ctf_file_t (if there are no types with conflicting definitions in the object files in the link) or a ctf_archive_t containing a large ctf_file_t (the common types) and a bunch of small ones named after individual CUs in which conflicting types are found (containing the conflicting types, and all types that reference them). A threshold size above which compression takes place is passed as one parameter. (Currently, only gzip compression is supported, but I hope to add lzma as well.) Lifetime rules for this are simple: don't close the input CTF files until you've called ctf_link for the last time. We do not assume that symbols or strings passed in by the callback outlast the call to ctf_link_add_strtab or ctf_link_shuffle_syms. Right now, the duplicate elimination mechanism is the one already present as part of the ctf_add_type function, and is not particularly good: it misses numerous actual duplicates, and the conflicting-types detection hardly ever reports that types conflict, even when they do (one of them just tends to get silently dropped): it is also very slow. This will all be fixed in the next few weeks, but the fix hardly touches any of this code, and the linker does work without it, just not as well as it otherwise might. (And when no CTF section is present, there is no effect on performance, of course. So only people using a trunk GCC with not-yet-committed patches will even notice. By the time it gets upstream, things should be better.) v3: Fix error handling. v4: check for strdup failure. v5: fix tabdamage. include/ * ctf-api.h (struct ctf_link_sym): New, a symbol in flight to the libctf linking machinery. (CTF_LINK_SHARE_UNCONFLICTED): New. (CTF_LINK_SHARE_DUPLICATED): New. (ECTF_LINKADDEDLATE): New, replacing ECTF_UNUSED. (ECTF_NOTYET): New, a 'not yet implemented' message. (ctf_link_add_ctf): New, add an input file's CTF to the link. (ctf_link): New, merge the type and string sections. (ctf_link_strtab_string_f): New, callback for feeding strtab info. (ctf_link_iter_symbol_f): New, callback for feeding symtab info. (ctf_link_add_strtab): New, tell the CTF linker about the ELF strtab's strings. (ctf_link_shuffle_syms): New, ask the CTF linker to shuffle its symbols into symtab order. (ctf_link_write): New, ask the CTF linker to write the CTF out. libctf/ * ctf-link.c: New file, linking of the string and type sections. * Makefile.am (libctf_a_SOURCES): Add it. * Makefile.in: Regenerate. * ctf-impl.h (ctf_file_t): New fields ctf_link_inputs, ctf_link_outputs. * ctf-create.c (ctf_update): Update accordingly. * ctf-open.c (ctf_file_close): Likewise. * ctf-error.c (_ctf_errlist): Updated with new errors.
2019-07-14 04:06:55 +08:00
ctf_dynhash_destroy (fp->ctf_link_inputs);
ctf_dynhash_destroy (fp->ctf_link_outputs);
libctf: map from old to corresponding newly-added types in ctf_add_type This lets you call ctf_type_mapping (dest_fp, src_fp, src_type_id) and get told what type ID the corresponding type has in the target ctf_file_t. This works even if it was added by a recursive call, and because it is stored in the target ctf_file_t it works even if we had to add one type to multiple ctf_file_t's as part of conflicting type handling. We empty out this mapping after every archive is linked: because it maps input to output fps, and we only visit each input fp once, its contents are rendered entirely useless every time the source fp changes. v3: add several missing mapping additions. Add ctf_dynhash_empty, and empty after every input archive. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_file_t): New field ctf_link_type_mapping. (struct ctf_link_type_mapping_key): New. (ctf_hash_type_mapping_key): Likewise. (ctf_hash_eq_type_mapping_key): Likewise. (ctf_add_type_mapping): Likewise. (ctf_type_mapping): Likewise. (ctf_dynhash_empty): Likewise. * ctf-open.c (ctf_file_close): Update accordingly. * ctf-create.c (ctf_update): Likewise. (ctf_add_type): Populate the mapping. * ctf-hash.c (ctf_hash_type_mapping_key): Hash a type mapping key. (ctf_hash_eq_type_mapping_key): Check the key for equality. (ctf_dynhash_insert): Fix comment typo. (ctf_dynhash_empty): New. * ctf-link.c (ctf_add_type_mapping): New. (ctf_type_mapping): Likewise. (empty_link_type_mapping): New. (ctf_link_one_input_archive): Call it.
2019-07-14 04:31:26 +08:00
ctf_dynhash_destroy (fp->ctf_link_type_mapping);
libctf: add CU-mapping machinery Once the deduplicator is capable of actually detecting conflicting types with the same name (i.e., not yet) we will place such conflicting types, and types that depend on them, into CTF dictionaries that are the child of the main dictionary we usually emit: currently, this will lead to the .ctf section becoming a CTF archive rather than a single dictionary, with the default-named archive member (_CTF_SECTION, or NULL) being the main shared dictionary with most of the types in it. By default, the sections are named after the compilation unit they come from (complete path and all), with the cuname field in the CTF header providing further evidence of the name without requiring the caller to engage in tiresome parsing. But some callers may not wish the mapping from input CU to output sub-dictionary to be purely CU-based. The machinery here allows this to be freely changed, in two ways: - callers can call ctf_link_add_cu_mapping to specify that a single input compilation unit should have its types placed in some other CU if they conflict: the CU will always be created, even if empty, so the consuming program can depend on its existence. You can map multiple input CUs to one output CU to force all their types to be merged together: if some of *those* types conflict, the behaviour is currently unspecified (the new deduplicator will specify it). - callers can call ctf_link_set_memb_name_changer to provide a function which is passed every CTF sub-dictionary name in turn (including _CTF_SECTION) and can return a new name, or NULL if no change is desired. The mapping from input to output names should not map two input names to the same output name: if this happens, the two are not merged but will result in an archive with two members with the same name (technically valid, but it's hard to access the second same-named member: you have to do an iteration over archive members). This is used by the kernel's ctfarchive machinery (not yet upstream) to encode CTF under member names like {module name}.ctf rather than .ctf.CU, but it is anticipated that other large projects may wish to have their own storage for CTF outside of .ctf sections and may wish to have new naming schemes that suit their special-purpose consumers. New in v3. v4: check for strdup failure. v5: fix tabdamage. include/ * ctf-api.h (ctf_link_add_cu_mapping): New. (ctf_link_memb_name_changer_f): New. (ctf_link_set_memb_name_changer): New. libctf/ * ctf-impl.h (ctf_file_t) <ctf_link_cu_mappping>: New. <ctf_link_memb_name_changer>: Likewise. <ctf_link_memb_name_changer_arg>: Likewise. * ctf-create.c (ctf_update): Update accordingly. * ctf-open.c (ctf_file_close): Likewise. * ctf-link.c (ctf_create_per_cu): Apply the cu mapping. (ctf_link_add_cu_mapping): New. (ctf_link_set_memb_name_changer): Likewise. (ctf_change_parent_name): New. (ctf_name_list_accum_cb_arg_t) <dynames>: New, storage for names allocated by the caller's ctf_link_memb_name_changer. <ndynames>: Likewise. (ctf_accumulate_archive_names): Call the ctf_link_memb_name_changer. (ctf_link_write): Likewise (for _CTF_SECTION only): also call ctf_change_parent_name. Free any resulting names.
2019-07-20 21:44:44 +08:00
ctf_dynhash_destroy (fp->ctf_link_cu_mapping);
libctf: properly handle ctf_add_type of forwards and self-reffing structs The code to handle structures (and unions) that refer to themselves in ctf_add_type is extremely dodgy. It works by looking through the list of not-yet-committed types for a structure with the same name as the structure in question and assuming, if it finds it, that this must be a reference to the same type. This is a linear search that gets ever slower as the dictionary grows, requiring you to call ctf_update at intervals to keep performance tolerable: but if you do that, you run into the problem that if a forward declared before the ctf_update is changed to a structure afterwards, ctf_update explodes. The last commit fixed most of this: this commit can use it, adding a new ctf_add_processing hash that tracks source type IDs that are currently being processed and uses it to avoid infinite recursion rather than the dynamic type list: we split ctf_add_type into a ctf_add_type_internal, so that ctf_add_type itself can become a wrapper that empties out this being-processed hash once the entire recursive type addition is over. Structure additions themselves avoid adding their dependent types quite so much by checking the type mapping and avoiding re-adding types we already know we have added. We also add support for adding forwards to dictionaries that already contain the thing they are a forward to: we just silently return the original type. v4: return existing struct/union/enum types properly, rather than using an uninitialized variable: shrinks sizes of CTF sections back down to roughly where they were in v1/v2 of this patch series. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_file_t) <ctf_add_processing>: New. * ctf-open.c (ctf_file_close): Free it. * ctf-create.c (ctf_serialize): Adjust. (membcmp): When reporting a conflict due to an error, report the error. (ctf_add_type): Turn into a ctf_add_processing wrapper. Rename to... (ctf_add_type_internal): ... this. Hand back types we are already in the middle of adding immediately. Hand back structs/unions with the same number of members immediately. Do not walk the dynamic list. Call ctf_add_type_internal, not ctf_add_type. Handle forwards promoted to other types and the inverse case identically. Add structs to the mapping as soon as we intern them, before they gain any members.
2019-08-08 01:01:08 +08:00
ctf_dynhash_destroy (fp->ctf_add_processing);
libctf: support getting strings from the ELF strtab The CTF file format has always supported "external strtabs", which internally are strtab offsets with their MSB on: such refs get their strings from the strtab passed in at CTF file open time: this is usually intended to be the ELF strtab, and that's what this implementation is meant to support, though in theory the external strtab could come from anywhere. This commit adds support for these external strings in the ctf-string.c strtab tracking layer. It's quite easy: we just add a field csa_offset to the atoms table that tracks all strings: this field tracks the offset of the string in the ELF strtab (with its MSB already on, courtesy of a new macro CTF_SET_STID), and adds a new function that sets the csa_offset to the specified offset (plus MSB). Then we just need to avoid writing out strings to the internal strtab if they have csa_offset set, and note that the internal strtab is shorter than it might otherwise be. (We could in theory save a little more time here by eschewing sorting such strings, since we never actually write the strings out anywhere, but that would mean storing them separately and it's just not worth the complexity cost until profiling shows it's worth doing.) We also have to go through a bit of extra effort at variable-sorting time. This was previously using direct references to the internal strtab: it couldn't use ctf_strptr or ctf_strraw because the new strtab is not yet ready to put in its usual field (in a ctf_file_t that hasn't even been allocated yet at this stage): but now we're using the external strtab, this will no longer do because it'll be looking things up in the wrong strtab, with disastrous results. Instead, pass the new internal strtab in to a new ctf_strraw_explicit function which is just like ctf_strraw except you can specify a ne winternal strtab to use. But even now that it is using a new internal strtab, this is not quite enough: it can't look up strings in the external strtab because ld hasn't written it out yet, and when it does will write it straight to disk. Instead, when we write the internal strtab, note all the offset -> string mappings that we have noted belong in the *external* strtab to a new "synthetic external strtab" dynhash, ctf_syn_ext_strtab, and look in there at ctf_strraw time if it is set. This uses minimal extra memory (because only strings in the external strtab that we actually use are stored, and even those come straight out of the atoms table), but let both variable sorting and name interning when ctf_bufopen is next called work fine. (This also means that we don't need to filter out spurious ECTF_STRTAB warnings from ctf_bufopen but can pass them back to the caller, once we wrap ctf_bufopen so that we have a new internal variant of ctf_bufopen etc that we can pass the synthetic external strtab to. That error has been filtered out since the days of Solaris libctf, which didn't try to handle the problem of getting external strtabs right at construction time at all.) v3: add the synthetic strtab and all associated machinery. v5: fix tabdamage. include/ * ctf.h (CTF_SET_STID): New. libctf/ * ctf-impl.h (ctf_str_atom_t) <csa_offset>: New field. (ctf_file_t) <ctf_syn_ext_strtab>: Likewise. (ctf_str_add_ref): Name the last arg. (ctf_str_add_external) New. (ctf_str_add_strraw_explicit): Likewise. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. * ctf-string.c (ctf_strraw_explicit): Split from... (ctf_strraw): ... here, with new support for ctf_syn_ext_strtab. (ctf_str_add_ref_internal): Return the atom, not the string. (ctf_str_add): Adjust accordingly. (ctf_str_add_ref): Likewise. Move up in the file. (ctf_str_add_external): New: update the csa_offset. (ctf_str_count_strtab): Only account for strings with no csa_offset in the internal strtab length. (ctf_str_write_strtab): If the csa_offset is set, update the string's refs without writing the string out, and update the ctf_syn_ext_strtab. Make OOM handling less ugly. * ctf-create.c (struct ctf_sort_var_arg_cb): New. (ctf_update): Handle failure to populate the strtab. Pass in the new ctf_sort_var arg. Adjust for ctf_syn_ext_strtab addition. Call ctf_simple_open_internal, not ctf_simple_open. (ctf_sort_var): Call ctf_strraw_explicit rather than looking up strings by hand. * ctf-hash.c (ctf_hash_insert_type): Likewise (but using ctf_strraw). Adjust to diagnose ECTF_STRTAB nonetheless. * ctf-open.c (init_types): No longer filter out ECTF_STRTAB. (ctf_file_close): Destroy the ctf_syn_ext_strtab. (ctf_simple_open): Rename to, and reimplement as a wrapper around... (ctf_simple_open_internal): ... this new function, which calls ctf_bufopen_internal. (ctf_bufopen): Rename to, and reimplement as a wrapper around... (ctf_bufopen_internal): ... this new function, which sets ctf_syn_ext_strtab.
2019-07-14 03:33:01 +08:00
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free (fp->ctf_sxlate);
free (fp->ctf_txlate);
free (fp->ctf_ptrtab);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free (fp->ctf_header);
free (fp);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
}
/* The converse of ctf_open(). ctf_open() disguises whatever it opens as an
archive, so closing one is just like closing an archive. */
void
ctf_close (ctf_archive_t *arc)
{
ctf_arc_close (arc);
}
libctf: mmappable archives If you need to store a large number of CTF containers somewhere, this provides a dedicated facility for doing so: an mmappable archive format like a very simple tar or ar without all the system-dependent format horrors or need for heavy file copying, with built-in compression of files above a particular size threshold. libctf automatically mmap()s uncompressed elements of these archives, or uncompresses them, as needed. (If the platform does not support mmap(), copying into dynamically-allocated buffers is used.) Archive iteration operations are partitioned into raw and non-raw forms. Raw operations pass thhe raw archive contents to the callback: non-raw forms open each member with ctf_bufopen() and pass the resulting ctf_file_t to the iterator instead. This lets you manipulate the raw data in the archive, or the contents interpreted as a CTF file, as needed. It is not yet known whether we will store CTF archives in a linked ELF object in one of these (akin to debugdata) or whether they'll get one section per TU plus one parent container for types shared between them. (In the case of ELF objects with very large numbers of TUs, an archive of all of them would seem preferable, so we might just use an archive, and add lzma support so you can assume that .gnu_debugdata and .ctf are compressed using the same algorithm if both are present.) To make usage easier, the ctf_archive_t is not the on-disk representation but an abstraction over both ctf_file_t's and archives of many ctf_file_t's: users see both CTF archives and raw CTF files as ctf_archive_t's upon opening, the only difference being that a raw CTF file has only a single "archive member", named ".ctf" (the default if a null pointer is passed in as the name). The next commit will make use of this facility, in addition to providing the public interface to actually open archives. (In the future, it should be possible to have all CTF sections in an ELF file appear as an "archive" in the same fashion.) This machinery is also used to allow library-internal creators of ctf_archive_t's (such as the next commit) to stash away an ELF string and symbol table, so that all opens of members in a given archive will use them. This lets CTF archives exploit the ELF string and symbol table just like raw CTF files can. (All this leads to somewhat confusing type naming. The ctf_archive_t is a typedef for the opaque internal type, struct ctf_archive_internal: the non-internal "struct ctf_archive" is the on-disk structure meant for other libraries manipulating CTF files. It is probably clearest to use the struct name for struct ctf_archive_internal inside the program, and the typedef names outside.) libctf/ * ctf-archive.c: New. * ctf-impl.h (ctf_archive_internal): New type. (ctf_arc_open_internal): New declaration. (ctf_arc_bufopen): Likewise. (ctf_arc_close_internal): Likewise. include/ * ctf.h (CTFA_MAGIC): New. (struct ctf_archive): New. (struct ctf_archive_modent): Likewise. * ctf-api.h (ctf_archive_member_f): New. (ctf_archive_raw_member_f): Likewise. (ctf_arc_write): Likewise. (ctf_arc_close): Likewise. (ctf_arc_open_by_name): Likewise. (ctf_archive_iter): Likewise. (ctf_archive_raw_iter): Likewise. (ctf_get_arc): Likewise.
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/* Get the CTF archive from which this ctf_file_t is derived. */
ctf_archive_t *
ctf_get_arc (const ctf_file_t *fp)
{
return fp->ctf_archive;
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
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/* Return the ctfsect out of the core ctf_impl. Useful for freeing the
ctfsect's data * after ctf_file_close(), which is why we return the actual
structure, not a pointer to it, since that is likely to become a pointer to
freed data before the return value is used under the expected use case of
ctf_getsect()/ ctf_file_close()/free(). */
libctf: avoid the need to ever use ctf_update The method of operation of libctf when the dictionary is writable has before now been that types that are added land in the dynamic type section, which is a linked list and hash of IDs -> dynamic type definitions (and, recently a hash of names): the DTDs are a bit of CTF representing the ctf_type_t and ad hoc C structures representing the vlen. Historically, libctf was unable to do anything with these types, not even look them up by ID, let alone by name: if you wanted to do that say if you were adding a type that depended on one you just added) you called ctf_update, which serializes all the DTDs into a CTF file and reopens it, copying its guts over the fp it's called with. The ctf_updated types are then frozen in amber and unchangeable: all lookups will return the types in the static portion in preference to the dynamic portion, and we will refuse to re-add things that already exist in the static portion (and, of late, in the dynamic portion too). The libctf machinery remembers the boundary between static and dynamic types and looks in the right portion for each type. Lots of things still don't quite work with dynamic types (e.g. getting their size), but enough works to do a bunch of additions and then a ctf_update, most of the time. Except it doesn't, because ctf_add_type finds it necessary to walk the full dynamic type definition list looking for types with matching names, so it gets slower and slower with every type you add: fixing this requires calling ctf_update periodically for no other reason than to avoid massively slowing things down. This is all clunky and very slow but kind of works, until you consider that it is in fact possible and indeed necessary to modify one sort of type after it has been added: forwards. These are necessarily promoted to structs, unions or enums, and when they do so *their type ID does not change*. So all of a sudden we are changing types that already exist in the static portion. ctf_update gets massively confused by this and allocates space enough for the forward (with no members), but then emits the new dynamic type (with all the members) into it. You get an assertion failure after that, if you're lucky, or a coredump. So this commit rejigs things a bit and arranges to exclusively use the dynamic type definitions in writable dictionaries, and the static type definitions in readable dictionaries: we don't at any time have a mixture of static and dynamic types, and you don't need to call ctf_update to make things "appear". The ctf_dtbyname hash I introduced a few months ago, which maps things like "struct foo" to DTDs, is removed, replaced instead by a change of type of the four dictionaries which track names. Rather than just being (unresizable) ctf_hash_t's populated only at ctf_bufopen time, they are now a ctf_names_t structure, which is a pair of ctf_hash_t and ctf_dynhash_t, with the ctf_hash_t portion being used in readonly dictionaries, and the ctf_dynhash_t being used in writable ones. The decision as to which to use is centralized in the new functions ctf_lookup_by_rawname (which takes a type kind) and ctf_lookup_by_rawhash, which it calls (which takes a ctf_names_t *.) This change lets us switch from using static to dynamic name hashes on the fly across the entirety of libctf without complexifying anything: in fact, because we now centralize the knowledge about how to map from type kind to name hash, it actually simplifies things and lets us throw out quite a lot of now-unnecessary complexity, from ctf_dtnyname (replaced by the dynamic half of the name tables), through to ctf_dtnextid (now that a dictionary's static portion is never referenced if the dictionary is writable, we can just use ctf_typemax to indicate the maximum type: dynamic or non-dynamic does not matter, and we no longer need to track the boundary between the types). You can now ctf_rollback() as far as you like, even past a ctf_update or for that matter a full writeout; all the iteration functions work just as well on writable as on read-only dictionaries; ctf_add_type no longer needs expensive duplicated code to run over the dynamic types hunting for ones it might be interested in; and the linker no longer needs a hack to call ctf_update so that calling ctf_add_type is not impossibly expensive. There is still a bit more complexity: some new code paths in ctf-types.c need to know how to extract information from dynamic types. This complexity will go away again in a few months when libctf acquires a proper intermediate representation. You can still call ctf_update if you like (it's public API, after all), but its only effect now is to set the point to which ctf_discard rolls back. Obviously *something* still needs to serialize the CTF file before writeout, and this job is done by ctf_serialize, which does everything ctf_update used to except set the counter used by ctf_discard. It is automatically called by the various functions that do CTF writeout: nobody else ever needs to call it. With this in place, forwards that are promoted to non-forwards no longer crash the link, even if it happens tens of thousands of types later. v5: fix tabdamage. libctf/ * ctf-impl.h (ctf_names_t): New. (ctf_lookup_t) <ctf_hash>: Now a ctf_names_t, not a ctf_hash_t. (ctf_file_t) <ctf_structs>: Likewise. <ctf_unions>: Likewise. <ctf_enums>: Likewise. <ctf_names>: Likewise. <ctf_lookups>: Improve comment. <ctf_ptrtab_len>: New. <ctf_prov_strtab>: New. <ctf_str_prov_offset>: New. <ctf_dtbyname>: Remove, redundant to the names hashes. <ctf_dtnextid>: Remove, redundant to ctf_typemax. (ctf_dtdef_t) <dtd_name>: Remove. <dtd_data>: Note that the ctt_name is now populated. (ctf_str_atom_t) <csa_offset>: This is now the strtab offset for internal strings too. <csa_external_offset>: New, the external strtab offset. (CTF_INDEX_TO_TYPEPTR): Handle the LCTF_RDWR case. (ctf_name_table): New declaration. (ctf_lookup_by_rawname): Likewise. (ctf_lookup_by_rawhash): Likewise. (ctf_set_ctl_hashes): Likewise. (ctf_serialize): Likewise. (ctf_dtd_insert): Adjust. (ctf_simple_open_internal): Likewise. (ctf_bufopen_internal): Likewise. (ctf_list_empty_p): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_add): Returns uint32_t now. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Now returns a boolean (int). * ctf-string.c (ctf_strraw_explicit): Check the ctf_prov_strtab for strings in the appropriate range. (ctf_str_create_atoms): Create the ctf_prov_strtab. Detect OOM when adding the null string to the new strtab. (ctf_str_free_atoms): Destroy the ctf_prov_strtab. (ctf_str_add_ref_internal): Add make_provisional argument. If make_provisional, populate the offset and fill in the ctf_prov_strtab accordingly. (ctf_str_add): Return the offset, not the string. (ctf_str_add_ref): Likewise. (ctf_str_add_external): Return a success integer. (ctf_str_remove_ref): New, remove a single ref. (ctf_str_count_strtab): Do not count the initial null string's length or the existence or length of any unreferenced internal atoms. (ctf_str_populate_sorttab): Skip atoms with no refs. (ctf_str_write_strtab): Populate the nullstr earlier. Add one to the cts_len for the null string, since it is no longer done in ctf_str_count_strtab. Adjust for csa_external_offset rename. Populate the csa_offset for both internal and external cases. Flush the ctf_prov_strtab afterwards, and reset the ctf_str_prov_offset. * ctf-create.c (ctf_grow_ptrtab): New. (ctf_create): Call it. Initialize new fields rather than old ones. Tell ctf_bufopen_internal that this is a writable dictionary. Set the ctl hashes and data model. (ctf_update): Rename to... (ctf_serialize): ... this. Leave a compatibility function behind. Tell ctf_simple_open_internal that this is a writable dictionary. Pass the new fields along from the old dictionary. Drop ctf_dtnextid and ctf_dtbyname. Use ctf_strraw, not dtd_name. Do not zero out the DTD's ctt_name. (ctf_prefixed_name): Rename to... (ctf_name_table): ... this. No longer return a prefixed name: return the applicable name table instead. (ctf_dtd_insert): Use it, and use the right name table. Pass in the kind we're adding. Migrate away from dtd_name. (ctf_dtd_delete): Adjust similarly. Remove the ref to the deleted ctt_name. (ctf_dtd_lookup_type_by_name): Remove. (ctf_dynamic_type): Always return NULL on read-only dictionaries. No longer check ctf_dtnextid: check ctf_typemax instead. (ctf_snapshot): No longer use ctf_dtnextid: use ctf_typemax instead. (ctf_rollback): Likewise. No longer fail with ECTF_OVERROLLBACK. Use ctf_name_table and the right name table, and migrate away from dtd_name as in ctf_dtd_delete. (ctf_add_generic): Pass in the kind explicitly and pass it to ctf_dtd_insert. Use ctf_typemax, not ctf_dtnextid. Migrate away from dtd_name to using ctf_str_add_ref to populate the ctt_name. Grow the ptrtab if needed. (ctf_add_encoded): Pass in the kind. (ctf_add_slice): Likewise. (ctf_add_array): Likewise. (ctf_add_function): Likewise. (ctf_add_typedef): Likewise. (ctf_add_reftype): Likewise. Initialize the ctf_ptrtab, checking ctt_name rather than dtd_name. (ctf_add_struct_sized): Pass in the kind. Use ctf_lookup_by_rawname, not ctf_hash_lookup_type / ctf_dtd_lookup_type_by_name. (ctf_add_union_sized): Likewise. (ctf_add_enum): Likewise. (ctf_add_enum_encoded): Likewise. (ctf_add_forward): Likewise. (ctf_add_type): Likewise. (ctf_compress_write): Call ctf_serialize: adjust for ctf_size not being initialized until after the call. (ctf_write_mem): Likewise. (ctf_write): Likewise. * ctf-archive.c (arc_write_one_ctf): Likewise. * ctf-lookup.c (ctf_lookup_by_name): Use ctf_lookuup_by_rawhash, not ctf_hash_lookup_type. (ctf_lookup_by_id): No longer check the readonly types if the dictionary is writable. * ctf-open.c (init_types): Assert that this dictionary is not writable. Adjust to use the new name hashes, ctf_name_table, and ctf_ptrtab_len. GNU style fix for the final ptrtab scan. (ctf_bufopen_internal): New 'writable' parameter. Flip on LCTF_RDWR if set. Drop out early when dictionary is writable. Split the ctf_lookups initialization into... (ctf_set_cth_hashes): ... this new function. (ctf_simple_open_internal): Adjust. New 'writable' parameter. (ctf_simple_open): Adjust accordingly. (ctf_bufopen): Likewise. (ctf_file_close): Destroy the appropriate name hashes. No longer destroy ctf_dtbyname, which is gone. (ctf_getdatasect): Remove spurious "extern". * ctf-types.c (ctf_lookup_by_rawname): New, look up types in the specified name table, given a kind. (ctf_lookup_by_rawhash): Likewise, given a ctf_names_t *. (ctf_member_iter): Add support for iterating over the dynamic type list. (ctf_enum_iter): Likewise. (ctf_variable_iter): Likewise. (ctf_type_rvisit): Likewise. (ctf_member_info): Add support for types in the dynamic type list. (ctf_enum_name): Likewise. (ctf_enum_value): Likewise. (ctf_func_type_info): Likewise. (ctf_func_type_args): Likewise. * ctf-link.c (ctf_accumulate_archive_names): No longer call ctf_update. (ctf_link_write): Likewise. (ctf_link_intern_extern_string): Adjust for new ctf_str_add_external return value. (ctf_link_add_strtab): Likewise. * ctf-util.c (ctf_list_empty_p): New.
2019-08-08 00:55:09 +08:00
ctf_sect_t
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
ctf_getdatasect (const ctf_file_t *fp)
{
return fp->ctf_data;
}
/* Return the CTF handle for the parent CTF container, if one exists.
Otherwise return NULL to indicate this container has no imported parent. */
ctf_file_t *
ctf_parent_file (ctf_file_t *fp)
{
return fp->ctf_parent;
}
/* Return the name of the parent CTF container, if one exists. Otherwise
return NULL to indicate this container is a root container. */
const char *
ctf_parent_name (ctf_file_t *fp)
{
return fp->ctf_parname;
}
/* Set the parent name. It is an error to call this routine without calling
ctf_import() at some point. */
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
int
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
ctf_parent_name_set (ctf_file_t *fp, const char *name)
{
if (fp->ctf_dynparname != NULL)
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free (fp->ctf_dynparname);
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
if ((fp->ctf_dynparname = strdup (name)) == NULL)
return (ctf_set_errno (fp, ENOMEM));
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
fp->ctf_parname = fp->ctf_dynparname;
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
return 0;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
}
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
/* Return the name of the compilation unit this CTF file applies to. Usually
non-NULL only for non-parent containers. */
const char *
ctf_cuname (ctf_file_t *fp)
{
return fp->ctf_cuname;
}
/* Set the compilation unit name. */
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
int
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
ctf_cuname_set (ctf_file_t *fp, const char *name)
{
if (fp->ctf_dyncuname != NULL)
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
free (fp->ctf_dyncuname);
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
if ((fp->ctf_dyncuname = strdup (name)) == NULL)
return (ctf_set_errno (fp, ENOMEM));
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
fp->ctf_cuname = fp->ctf_dyncuname;
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
return 0;
libctf: allow the header to change between versions libctf supports dynamic upgrading of the type table as file format versions change, but before now has not supported changes to the CTF header. Doing this is complicated by the baroque storage method used: the CTF header is kept prepended to the rest of the CTF data, just as when read from the file, and written out from there, and is endian-flipped in place. This makes accessing it needlessly hard and makes it almost impossible to make the header larger if we add fields. The general storage machinery around the malloced ctf pointer (the 'ctf_base') is also overcomplicated: the pointer is sometimes malloced locally and sometimes assigned from a parameter, so freeing it requires checking to see if that parameter was used, needlessly coupling ctf_bufopen and ctf_file_close together. So split the header out into a new ctf_file_t.ctf_header, which is written out explicitly: squeeze it out of the CTF buffer whenever we reallocate it, and use ctf_file_t.ctf_buf to skip past the header when we do not need to reallocate (when no upgrading or endian-flipping is required). We now track whether the CTF base can be freed explicitly via a new ctf_dynbase pointer which is non-NULL only when freeing is possible. With all this done, we can upgrade the header on the fly and add new fields as desired, via a new upgrade_header function in ctf-open. As with other forms of upgrading, libctf upgrades older headers automatically to the latest supported version at open time. For a first use of this field, we add a new string field cth_cuname, and a corresponding setter/getter pair ctf_cuname_set and ctf_cuname: this is used by debuggers to determine whether a CTF section's types relate to a single compilation unit, or to all compilation units in the program. (Types with ambiguous definitions in different CUs have only one of these types placed in the top-level shared .ctf container: the rest are placed in much smaller per-CU containers, which have the shared container as their parent. Since CTF must be useful in the absence of DWARF, we store the names of the relevant CUs ourselves, so the debugger can look them up.) v5: fix tabdamage. include/ * ctf-api.h (ctf_cuname): New function. (ctf_cuname_set): Likewise. * ctf.h: Improve comment around upgrading, no longer implying that v2 is the target of upgrades (it is v3 now). (ctf_header_v2_t): New, old-format header for backward compatibility. (ctf_header_t): Add cth_cuname: this is the first of several header changes in format v3. libctf/ * ctf-impl.h (ctf_file_t): New fields ctf_header, ctf_dynbase, ctf_cuname, ctf_dyncuname: ctf_base and ctf_buf are no longer const. * ctf-open.c (ctf_set_base): Preserve the gap between ctf_buf and ctf_base: do not assume that it is always sizeof (ctf_header_t). Print out ctf_cuname: only print out ctf_parname if set. (ctf_free_base): Removed, ctf_base is no longer freed: free ctf_dynbase instead. (ctf_set_version): Fix spacing. (upgrade_header): New, in-place header upgrading. (upgrade_types): Rename to... (upgrade_types_v1): ... this. Free ctf_dynbase, not ctf_base. No longer track old and new headers separately. No longer allow for header sizes explicitly: squeeze the headers out on upgrade (they are preserved in fp->ctf_header). Set ctf_dynbase, ctf_base and ctf_buf explicitly. Use ctf_free, not ctf_free_base. (upgrade_types): New, also handle ctf_parmax updating. (flip_header): Flip ctf_cuname. (flip_types): Flip BUF explicitly rather than deriving BUF from BASE. (ctf_bufopen): Store the header in fp->ctf_header. Correct minimum required alignment of objtoff and funcoff. No longer store it in the ctf_buf unless that buf is derived unmodified from the input. Set ctf_dynbase where ctf_base is dynamically allocated. Drop locals that duplicate fields in ctf_file: move allocation of ctf_file further up instead. Call upgrade_header as needed. Move version-specific ctf_parmax initialization into upgrade_types. More concise error handling. (ctf_file_close): No longer test for null pointers before freeing. Free ctf_dyncuname, ctf_dynbase, and ctf_header. Do not call ctf_free_base. (ctf_cuname): New. (ctf_cuname_set): New. * ctf-create.c (ctf_update): Populate ctf_cuname. (ctf_gzwrite): Write out the header explicitly. Remove obsolescent comment. (ctf_write): Likewise. (ctf_compress_write): Get the header from ctf_header, not ctf_base. Fix the compression length: fp->ctf_size never counted the CTF header. Simplify the compress call accordingly.
2019-07-07 00:36:21 +08:00
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
/* Import the types from the specified parent container by storing a pointer
to it in ctf_parent and incrementing its reference count. Only one parent
is allowed: if a parent already exists, it is replaced by the new parent. */
int
ctf_import (ctf_file_t *fp, ctf_file_t *pfp)
{
if (fp == NULL || fp == pfp || (pfp != NULL && pfp->ctf_refcnt == 0))
return (ctf_set_errno (fp, EINVAL));
if (pfp != NULL && pfp->ctf_dmodel != fp->ctf_dmodel)
return (ctf_set_errno (fp, ECTF_DMODEL));
if (fp->ctf_parent != NULL)
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
{
fp->ctf_parent->ctf_refcnt--;
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
ctf_file_close (fp->ctf_parent);
fp->ctf_parent = NULL;
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (pfp != NULL)
{
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
int err;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
if (fp->ctf_parname == NULL)
libctf: remove ctf_malloc, ctf_free and ctf_strdup These just get in the way of auditing for erroneous usage of strdup and add a huge irregular surface of "ctf_malloc or malloc? ctf_free or free? ctf_strdup or strdup?" ctf_malloc and ctf_free usage has not reliably matched up for many years, if ever, making the whole game pointless. Go back to malloc, free, and strdup like everyone else: while we're at it, fix a bunch of places where we weren't properly checking for OOM. This changes the interface of ctf_cuname_set and ctf_parent_name_set, which could strdup but could not return errors (like ENOMEM). New in v4. include/ * ctf-api.h (ctf_cuname_set): Can now fail, returning int. (ctf_parent_name_set): Likewise. libctf/ * ctf-impl.h (ctf_alloc): Remove. (ctf_free): Likewise. (ctf_strdup): Likewise. * ctf-subr.c (ctf_alloc): Remove. (ctf_free): Likewise. * ctf-util.c (ctf_strdup): Remove. * ctf-create.c (ctf_serialize): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dtd_delete): Likewise. (ctf_dvd_delete): Likewise. (ctf_add_generic): Likewise. (ctf_add_function): Likewise. (ctf_add_enumerator): Likewise. (ctf_add_member_offset): Likewise. (ctf_add_variable): Likewise. (membadd): Likewise. (ctf_compress_write): Likewise. (ctf_write_mem): Likewise. * ctf-decl.c (ctf_decl_push): Likewise. (ctf_decl_fini): Likewise. (ctf_decl_sprintf): Likewise. Check for OOM. * ctf-dump.c (ctf_dump_append): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_dump_free): Likewise. (ctf_dump): Likewise. * ctf-open.c (upgrade_types_v1): Likewise. (init_types): Likewise. (ctf_file_close): Likewise. (ctf_bufopen_internal): Likewise. Check for OOM. (ctf_parent_name_set): Likewise: report the OOM to the caller. (ctf_cuname_set): Likewise. (ctf_import): Likewise. * ctf-string.c (ctf_str_purge_atom_refs): Use malloc, not ctf_alloc; free, not ctf_free; strdup, not ctf_strdup. (ctf_str_free_atom): Likewise. (ctf_str_create_atoms): Likewise. (ctf_str_add_ref_internal): Likewise. (ctf_str_remove_ref): Likewise. (ctf_str_write_strtab): Likewise.
2019-09-17 13:54:23 +08:00
if ((err = ctf_parent_name_set (fp, "PARENT")) < 0)
return err;
fp->ctf_flags |= LCTF_CHILD;
pfp->ctf_refcnt++;
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
}
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
fp->ctf_parent = pfp;
return 0;
}
/* Set the data model constant for the CTF container. */
int
ctf_setmodel (ctf_file_t *fp, int model)
{
const ctf_dmodel_t *dp;
for (dp = _libctf_models; dp->ctd_name != NULL; dp++)
{
if (dp->ctd_code == model)
{
fp->ctf_dmodel = dp;
return 0;
}
}
return (ctf_set_errno (fp, EINVAL));
}
/* Return the data model constant for the CTF container. */
int
ctf_getmodel (ctf_file_t *fp)
{
return fp->ctf_dmodel->ctd_code;
}
libctf: fix a number of build problems found on Solaris and NetBSD - Use of nonportable <endian.h> - Use of qsort_r - Use of zlib without appropriate magic to pull in the binutils zlib - Use of off64_t without checking (fixed by dropping the unused fields that need off64_t entirely) - signedness problems due to long being too short a type on 32-bit platforms: ctf_id_t is now 'unsigned long', and CTF_ERR must be used only for functions that return ctf_id_t - One lingering use of bzero() and of <sys/errno.h> All fixed, using code from gnulib where possible. Relatedly, set cts_size in a couple of places it was missed (string table and symbol table loading upon ctf_bfdopen()). binutils/ * objdump.c (make_ctfsect): Drop cts_type, cts_flags, and cts_offset. * readelf.c (shdr_to_ctf_sect): Likewise. include/ * ctf-api.h (ctf_sect_t): Drop cts_type, cts_flags, and cts_offset. (ctf_id_t): This is now an unsigned type. (CTF_ERR): Cast it to ctf_id_t. Note that it should only be used for ctf_id_t-returning functions. libctf/ * Makefile.am (ZLIB): New. (ZLIBINC): Likewise. (AM_CFLAGS): Use them. (libctf_a_LIBADD): New, for LIBOBJS. * configure.ac: Check for zlib, endian.h, and qsort_r. * ctf-endian.h: New, providing htole64 and le64toh. * swap.h: Code style fixes. (bswap_identity_64): New. * qsort_r.c: New, from gnulib (with one added #include). * ctf-decls.h: New, providing a conditional qsort_r declaration, and unconditional definitions of MIN and MAX. * ctf-impl.h: Use it. Do not use <sys/errno.h>. (ctf_set_errno): Now returns unsigned long. * ctf-util.c (ctf_set_errno): Adjust here too. * ctf-archive.c: Use ctf-endian.h. (ctf_arc_open_by_offset): Use memset, not bzero. Drop cts_type, cts_flags and cts_offset. (ctf_arc_write): Drop debugging dependent on the size of off_t. * ctf-create.c: Provide a definition of roundup if not defined. (ctf_create): Drop cts_type, cts_flags and cts_offset. (ctf_add_reftype): Do not check if type IDs are below zero. (ctf_add_slice): Likewise. (ctf_add_typedef): Likewise. (ctf_add_member_offset): Cast error-returning ssize_t's to size_t when known error-free. Drop CTF_ERR usage for functions returning int. (ctf_add_member_encoded): Drop CTF_ERR usage for functions returning int. (ctf_add_variable): Likewise. (enumcmp): Likewise. (enumadd): Likewise. (membcmp): Likewise. (ctf_add_type): Likewise. Cast error-returning ssize_t's to size_t when known error-free. * ctf-dump.c (ctf_is_slice): Drop CTF_ERR usage for functions returning int: use CTF_ERR for functions returning ctf_type_id. (ctf_dump_label): Likewise. (ctf_dump_objts): Likewise. * ctf-labels.c (ctf_label_topmost): Likewise. (ctf_label_iter): Likewise. (ctf_label_info): Likewise. * ctf-lookup.c (ctf_func_args): Likewise. * ctf-open.c (upgrade_types): Cast to size_t where appropriate. (ctf_bufopen): Likewise. Use zlib types as needed. * ctf-types.c (ctf_member_iter): Drop CTF_ERR usage for functions returning int. (ctf_enum_iter): Likewise. (ctf_type_size): Likewise. (ctf_type_align): Likewise. Cast to size_t where appropriate. (ctf_type_kind_unsliced): Likewise. (ctf_type_kind): Likewise. (ctf_type_encoding): Likewise. (ctf_member_info): Likewise. (ctf_array_info): Likewise. (ctf_enum_value): Likewise. (ctf_type_rvisit): Likewise. * ctf-open-bfd.c (ctf_bfdopen): Drop cts_type, cts_flags and cts_offset. (ctf_simple_open): Likewise. (ctf_bfdopen_ctfsect): Likewise. Set cts_size properly. * Makefile.in: Regenerate. * aclocal.m4: Likewise. * config.h: Likewise. * configure: Likewise.
2019-05-31 17:10:51 +08:00
/* The caller can hang an arbitrary pointer off each ctf_file_t using this
function. */
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
void
ctf_setspecific (ctf_file_t *fp, void *data)
{
fp->ctf_specific = data;
}
libctf: fix a number of build problems found on Solaris and NetBSD - Use of nonportable <endian.h> - Use of qsort_r - Use of zlib without appropriate magic to pull in the binutils zlib - Use of off64_t without checking (fixed by dropping the unused fields that need off64_t entirely) - signedness problems due to long being too short a type on 32-bit platforms: ctf_id_t is now 'unsigned long', and CTF_ERR must be used only for functions that return ctf_id_t - One lingering use of bzero() and of <sys/errno.h> All fixed, using code from gnulib where possible. Relatedly, set cts_size in a couple of places it was missed (string table and symbol table loading upon ctf_bfdopen()). binutils/ * objdump.c (make_ctfsect): Drop cts_type, cts_flags, and cts_offset. * readelf.c (shdr_to_ctf_sect): Likewise. include/ * ctf-api.h (ctf_sect_t): Drop cts_type, cts_flags, and cts_offset. (ctf_id_t): This is now an unsigned type. (CTF_ERR): Cast it to ctf_id_t. Note that it should only be used for ctf_id_t-returning functions. libctf/ * Makefile.am (ZLIB): New. (ZLIBINC): Likewise. (AM_CFLAGS): Use them. (libctf_a_LIBADD): New, for LIBOBJS. * configure.ac: Check for zlib, endian.h, and qsort_r. * ctf-endian.h: New, providing htole64 and le64toh. * swap.h: Code style fixes. (bswap_identity_64): New. * qsort_r.c: New, from gnulib (with one added #include). * ctf-decls.h: New, providing a conditional qsort_r declaration, and unconditional definitions of MIN and MAX. * ctf-impl.h: Use it. Do not use <sys/errno.h>. (ctf_set_errno): Now returns unsigned long. * ctf-util.c (ctf_set_errno): Adjust here too. * ctf-archive.c: Use ctf-endian.h. (ctf_arc_open_by_offset): Use memset, not bzero. Drop cts_type, cts_flags and cts_offset. (ctf_arc_write): Drop debugging dependent on the size of off_t. * ctf-create.c: Provide a definition of roundup if not defined. (ctf_create): Drop cts_type, cts_flags and cts_offset. (ctf_add_reftype): Do not check if type IDs are below zero. (ctf_add_slice): Likewise. (ctf_add_typedef): Likewise. (ctf_add_member_offset): Cast error-returning ssize_t's to size_t when known error-free. Drop CTF_ERR usage for functions returning int. (ctf_add_member_encoded): Drop CTF_ERR usage for functions returning int. (ctf_add_variable): Likewise. (enumcmp): Likewise. (enumadd): Likewise. (membcmp): Likewise. (ctf_add_type): Likewise. Cast error-returning ssize_t's to size_t when known error-free. * ctf-dump.c (ctf_is_slice): Drop CTF_ERR usage for functions returning int: use CTF_ERR for functions returning ctf_type_id. (ctf_dump_label): Likewise. (ctf_dump_objts): Likewise. * ctf-labels.c (ctf_label_topmost): Likewise. (ctf_label_iter): Likewise. (ctf_label_info): Likewise. * ctf-lookup.c (ctf_func_args): Likewise. * ctf-open.c (upgrade_types): Cast to size_t where appropriate. (ctf_bufopen): Likewise. Use zlib types as needed. * ctf-types.c (ctf_member_iter): Drop CTF_ERR usage for functions returning int. (ctf_enum_iter): Likewise. (ctf_type_size): Likewise. (ctf_type_align): Likewise. Cast to size_t where appropriate. (ctf_type_kind_unsliced): Likewise. (ctf_type_kind): Likewise. (ctf_type_encoding): Likewise. (ctf_member_info): Likewise. (ctf_array_info): Likewise. (ctf_enum_value): Likewise. (ctf_type_rvisit): Likewise. * ctf-open-bfd.c (ctf_bfdopen): Drop cts_type, cts_flags and cts_offset. (ctf_simple_open): Likewise. (ctf_bfdopen_ctfsect): Likewise. Set cts_size properly. * Makefile.in: Regenerate. * aclocal.m4: Likewise. * config.h: Likewise. * configure: Likewise.
2019-05-31 17:10:51 +08:00
/* Retrieve the arbitrary pointer again. */
libctf: opening This fills in the other half of the opening/creation puzzle: opening of already-existing CTF files. Such files are always read-only: if you want to add to a CTF file opened with one of the opening functions in this file, use ctf_add_type(), in a later commit, to copy appropriate types into a newly ctf_create()d, writable container. The lowest-level opening functions are in here: ctf_bufopen(), which takes ctf_sect_t structures akin to ELF section headers, and ctf_simple_open(), which can be used if you don't have an entire ELF section header to work from. Both will malloc() new space for the buffers only if necessary, will mmap() directly from the file if requested, and will mprotect() it afterwards to prevent accidental corruption of the types. These functions are also used by ctf_update() when converting types in a writable container into read-only types that can be looked up using the lookup functions (in later commits). The files are always of the native endianness of the system that created them: at read time, the endianness of the header magic number is used to determine whether or not the file needs byte-swapping, and the entire thing is aggressively byte-swapped. The agggressive nature of this swapping avoids complicating the rest of the code with endianness conversions, while the native endianness introduces no byte-swapping overhead in the common case. (The endianness-independence code is also much newer than everything else in this file, and deserves closer scrutiny.) The accessors at the top of the file are there to transparently support older versions of the CTF file format, allowing translation from older formats that have different sizes for the structures in ctf.h: currently, these older formats are intermingled with the newer ones in ctf.h: they will probably migrate to a compatibility header in time, to ease readability. The ctf_set_base() function is split out for the same reason: when conversion code to a newer format is written, it would need to malloc() new storage for the entire ctf_file_t if a file format change causes it to grow, and for that we need ctf_set_base() to be a separate function. One pair of linked data structures supported by this file has no creation code in libctf yet: the data and function object sections read by init_symtab(). These will probably arrive soon, when the linker comes to need them. (init_symtab() has hardly been changed since 2009, but if any code in libctf has rotted over time, this will.) A few simple accessors are also present that can even be called on read-only containers because they don't actually modify them, since the relevant things are not stored in the container but merely change its operation: ctf_setmodel(), which lets you specify whether a container is LP64 or not (used to statically determine the sizes of a few types), ctf_import(), which is the only way to associate a parent container with a child container, and ctf_setspecific(), which lets the caller associate an arbitrary pointer with the CTF container for any use. If the user doesn't call these functions correctly, libctf will misbehave: this is particularly important for ctf_import(), since a container built against a given parent container will not be able to resolve types that depend on types in the parent unless it is ctf_import()ed with a parent container with the same set of types at the same IDs, or a superset. Possible future extensions (also noted in the ctf-hash.c file) include storing a count of things so that we don't need to do one pass over the CTF file counting everything, and computing a perfect hash at CTF creation time in some compact form, storing it in the CTF file, and using it to hash things so we don't need to do a second pass over the entire CTF file to set up the hashes used to go from names to type IDs. (There are multiple such hashes, one for each C type namespace: types, enums, structs, and unions.) libctf/ * ctf-open.c: New file. * swap.h: Likewise. include/ * ctf-api.h (ctf_file_close): New declaration. (ctf_getdatasect): Likewise. (ctf_parent_file): Likewise. (ctf_parent_name): Likewise. (ctf_parent_name_set): Likewise. (ctf_import): Likewise. (ctf_setmodel): Likewise. (ctf_getmodel): Likewise. (ctf_setspecific): Likewise. (ctf_getspecific): Likewise.
2019-04-24 17:17:13 +08:00
void *
ctf_getspecific (ctf_file_t *fp)
{
return fp->ctf_specific;
}