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d9cb1a7dad
* elf/dl-deps.c (_dl_map_object_deps): Change return type and remove last parameter. Move code to add map to global scope from here... * elf/dl-open.c (dl_open_worker): ...here. * elf/ldsodefs.h: Adjust declaration of _dl_map_object_deps. * elf/rtld.c: Adjust call to _dl_map_object_deps.
483 lines
15 KiB
C
483 lines
15 KiB
C
/* Load the dependencies of a mapped object.
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Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <assert.h>
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#include <dlfcn.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/param.h>
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#include <elf/ldsodefs.h>
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#include <dl-dst.h>
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/* Whether an shared object references one or more auxiliary objects
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is signaled by the AUXTAG entry in l_info. */
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#define AUXTAG (DT_NUM + DT_PROCNUM + DT_VERSIONTAGNUM \
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+ DT_EXTRATAGIDX (DT_AUXILIARY))
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/* Whether an shared object references one or more auxiliary objects
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is signaled by the AUXTAG entry in l_info. */
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#define FILTERTAG (DT_NUM + DT_PROCNUM + DT_VERSIONTAGNUM \
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+ DT_EXTRATAGIDX (DT_FILTER))
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/* This is zero at program start to signal that the global scope map is
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allocated by rtld. Later it keeps the size of the map. It might be
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reset if in _dl_close if the last global object is removed. */
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size_t _dl_global_scope_alloc;
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extern size_t _dl_platformlen;
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/* When loading auxiliary objects we must ignore errors. It's ok if
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an object is missing. */
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struct openaux_args
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{
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/* The arguments to openaux. */
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struct link_map *map;
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int trace_mode;
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const char *strtab;
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const char *name;
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/* The return value of openaux. */
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struct link_map *aux;
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};
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static void
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openaux (void *a)
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{
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struct openaux_args *args = (struct openaux_args *) a;
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args->aux = _dl_map_object (args->map, args->name, 0,
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(args->map->l_type == lt_executable
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? lt_library : args->map->l_type),
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args->trace_mode);
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}
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/* We use a very special kind of list to track the two kinds paths
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through the list of loaded shared objects. We have to
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- produce a flat list with unique members of all involved objects
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- produce a flat list of all shared objects.
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*/
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struct list
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{
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int done; /* Nonzero if this map was processed. */
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struct link_map *map; /* The data. */
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struct list *unique; /* Elements for normal list. */
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struct list *dup; /* Elements in complete list. */
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};
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/* Macro to expand DST. It is an macro since we use `alloca'. */
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#define expand_dst(l, str, fatal) \
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({ \
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const char *__str = (str); \
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const char *__result = __str; \
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size_t __cnt = DL_DST_COUNT(__str, 0); \
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\
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if (__cnt != 0) \
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{ \
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char *__newp; \
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\
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/* DST must not appear in SUID/SGID programs. */ \
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if (__libc_enable_secure) \
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_dl_signal_error (0, __str, \
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"DST not allowed in SUID/SGID programs"); \
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\
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__newp = (char *) alloca (DL_DST_REQUIRED (l, __str, strlen (__str), \
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__cnt)); \
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\
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__result = DL_DST_SUBSTITUTE (l, __str, __newp, 0); \
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\
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if (*__result == '\0') \
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{ \
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/* The replacement for the DST is not known. We can't \
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processed. */ \
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if (fatal) \
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_dl_signal_error (0, __str, \
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"empty dynamics string token substitution"); \
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else \
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{ \
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/* This is for DT_AUXILIARY. */ \
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if (_dl_debug_libs) \
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_dl_debug_message (1, "cannot load auxiliary `", __str, \
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"' because of empty dynamic string" \
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" token substitution\n", NULL); \
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continue; \
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} \
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} \
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} \
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\
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__result; })
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void
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internal_function
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_dl_map_object_deps (struct link_map *map,
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struct link_map **preloads, unsigned int npreloads,
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int trace_mode)
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{
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struct list known[1 + npreloads + 1];
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struct list *runp, *utail, *dtail;
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unsigned int nlist, nduplist, i;
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inline void preload (struct link_map *map)
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{
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known[nlist].done = 0;
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known[nlist].map = map;
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known[nlist].unique = &known[nlist + 1];
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known[nlist].dup = &known[nlist + 1];
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++nlist;
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/* We use `l_reserved' as a mark bit to detect objects we have
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already put in the search list and avoid adding duplicate
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elements later in the list. */
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map->l_reserved = 1;
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}
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/* No loaded object so far. */
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nlist = 0;
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/* First load MAP itself. */
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preload (map);
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/* Add the preloaded items after MAP but before any of its dependencies. */
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for (i = 0; i < npreloads; ++i)
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preload (preloads[i]);
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/* Terminate the lists. */
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known[nlist - 1].unique = NULL;
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known[nlist - 1].dup = NULL;
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/* Pointer to last unique object. */
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utail = &known[nlist - 1];
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/* Pointer to last loaded object. */
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dtail = &known[nlist - 1];
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/* Until now we have the same number of libraries in the normal and
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the list with duplicates. */
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nduplist = nlist;
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/* Process each element of the search list, loading each of its
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auxiliary objects and immediate dependencies. Auxiliary objects
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will be added in the list before the object itself and
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dependencies will be appended to the list as we step through it.
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This produces a flat, ordered list that represents a
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breadth-first search of the dependency tree.
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The whole process is complicated by the fact that we better
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should use alloca for the temporary list elements. But using
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alloca means we cannot use recursive function calls. */
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for (runp = known; runp; )
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{
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struct link_map *l = runp->map;
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if (l->l_info[DT_NEEDED] || l->l_info[AUXTAG] || l->l_info[FILTERTAG])
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{
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const char *strtab = (const void *) l->l_info[DT_STRTAB]->d_un.d_ptr;
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struct openaux_args args;
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struct list *orig;
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const ElfW(Dyn) *d;
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/* Mark map as processed. */
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runp->done = 1;
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args.strtab = strtab;
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args.map = l;
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args.trace_mode = trace_mode;
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orig = runp;
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for (d = l->l_ld; d->d_tag != DT_NULL; ++d)
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if (__builtin_expect (d->d_tag, DT_NEEDED) == DT_NEEDED)
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{
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/* Map in the needed object. */
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struct link_map *dep;
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/* Allocate new entry. */
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struct list *newp;
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/* Object name. */
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const char *name;
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/* Recognize DSTs. */
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name = expand_dst (l, strtab + d->d_un.d_val, 0);
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dep = _dl_map_object (l, name, 0,
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l->l_type == lt_executable ? lt_library :
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l->l_type, trace_mode);
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/* Add it in any case to the duplicate list. */
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newp = alloca (sizeof (struct list));
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newp->map = dep;
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newp->dup = NULL;
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dtail->dup = newp;
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dtail = newp;
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++nduplist;
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if (dep->l_reserved)
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/* This object is already in the search list we are
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building. Don't add a duplicate pointer.
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Release the reference just added by
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_dl_map_object. */
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--dep->l_opencount;
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else
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{
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/* Append DEP to the unique list. */
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newp->done = 0;
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newp->unique = NULL;
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utail->unique = newp;
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utail = newp;
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++nlist;
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/* Set the mark bit that says it's already in the list. */
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dep->l_reserved = 1;
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}
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}
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else if (d->d_tag == DT_AUXILIARY || d->d_tag == DT_FILTER)
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{
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char *errstring;
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struct list *newp;
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/* Object name. */
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const char *name;
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/* Recognize DSTs. */
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name = expand_dst (l, strtab + d->d_un.d_val,
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d->d_tag == DT_AUXILIARY);
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if (d->d_tag == DT_AUXILIARY)
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{
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/* Store the tag in the argument structure. */
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args.name = name;
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/* Say that we are about to load an auxiliary library. */
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if (_dl_debug_libs)
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_dl_debug_message (1, "load auxiliary object=",
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name, " requested by file=",
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l->l_name[0]
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? l->l_name : _dl_argv[0],
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"\n", NULL);
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/* We must be prepared that the addressed shared
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object is not available. */
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if (_dl_catch_error (&errstring, openaux, &args))
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{
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/* We are not interested in the error message. */
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assert (errstring != NULL);
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free (errstring);
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/* Simply ignore this error and continue the work. */
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continue;
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}
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}
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else
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{
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/* Say that we are about to load an auxiliary library. */
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if (_dl_debug_libs)
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_dl_debug_message (1, "load filtered object=", name,
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" requested by file=",
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l->l_name[0]
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? l->l_name : _dl_argv[0],
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"\n", NULL);
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/* For filter objects the dependency must be available. */
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args.aux = _dl_map_object (l, name, 0,
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(l->l_type == lt_executable
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? lt_library : l->l_type),
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trace_mode);
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}
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/* The auxiliary object is actually available.
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Incorporate the map in all the lists. */
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/* Allocate new entry. This always has to be done. */
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newp = alloca (sizeof (struct list));
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/* We want to insert the new map before the current one,
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but we have no back links. So we copy the contents of
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the current entry over. Note that ORIG and NEWP now
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have switched their meanings. */
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orig->dup = memcpy (newp, orig, sizeof (*newp));
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/* Initialize new entry. */
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orig->done = 0;
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orig->map = args.aux;
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/* We must handle two situations here: the map is new,
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so we must add it in all three lists. If the map
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is already known, we have two further possibilities:
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- if the object is before the current map in the
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search list, we do nothing. It is already found
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early
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- if the object is after the current one, we must
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move it just before the current map to make sure
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the symbols are found early enough
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*/
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if (args.aux->l_reserved)
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{
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/* The object is already somewhere in the list.
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Locate it first. */
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struct list *late;
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/* This object is already in the search list we
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are building. Don't add a duplicate pointer.
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Release the reference just added by
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_dl_map_object. */
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--args.aux->l_opencount;
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for (late = newp; late->unique; late = late->unique)
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if (late->unique->map == args.aux)
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break;
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if (late->unique)
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{
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/* The object is somewhere behind the current
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position in the search path. We have to
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move it to this earlier position. */
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orig->unique = newp;
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/* Now remove the later entry from the unique list
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and adjust the tail pointer. */
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if (utail == late->unique)
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utail = late;
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late->unique = late->unique->unique;
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/* We must move the object earlier in the chain. */
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if (args.aux->l_prev)
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args.aux->l_prev->l_next = args.aux->l_next;
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if (args.aux->l_next)
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args.aux->l_next->l_prev = args.aux->l_prev;
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args.aux->l_prev = newp->map->l_prev;
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newp->map->l_prev = args.aux;
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if (args.aux->l_prev != NULL)
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args.aux->l_prev->l_next = args.aux;
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args.aux->l_next = newp->map;
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}
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else
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{
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/* The object must be somewhere earlier in the
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list. That's good, we only have to insert
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an entry for the duplicate list. */
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orig->unique = NULL; /* Never used. */
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/* Now we have a problem. The element
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pointing to ORIG in the unique list must
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point to NEWP now. This is the only place
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where we need this backreference and this
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situation is really not that frequent. So
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we don't use a double-linked list but
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instead search for the preceding element. */
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late = known;
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while (late->unique != orig)
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late = late->unique;
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late->unique = newp;
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}
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}
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else
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{
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/* This is easy. We just add the symbol right here. */
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orig->unique = newp;
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++nlist;
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/* Set the mark bit that says it's already in the list. */
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args.aux->l_reserved = 1;
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/* The only problem is that in the double linked
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list of all objects we don't have this new
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object at the correct place. Correct this here. */
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if (args.aux->l_prev)
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args.aux->l_prev->l_next = args.aux->l_next;
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if (args.aux->l_next)
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args.aux->l_next->l_prev = args.aux->l_prev;
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args.aux->l_prev = newp->map->l_prev;
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newp->map->l_prev = args.aux;
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if (args.aux->l_prev != NULL)
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args.aux->l_prev->l_next = args.aux;
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args.aux->l_next = newp->map;
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}
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/* Move the tail pointers if necessary. */
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if (orig == utail)
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utail = newp;
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if (orig == dtail)
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dtail = newp;
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/* Move on the insert point. */
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orig = newp;
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/* We always add an entry to the duplicate list. */
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++nduplist;
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}
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}
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else
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/* Mark as processed. */
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runp->done = 1;
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/* If we have no auxiliary objects just go on to the next map. */
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if (runp->done)
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do
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runp = runp->unique;
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while (runp != NULL && runp->done);
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}
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/* Store the search list we built in the object. It will be used for
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searches in the scope of this object. */
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map->l_searchlist.r_list = malloc (nlist * sizeof (struct link_map *));
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if (map->l_searchlist.r_list == NULL)
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_dl_signal_error (ENOMEM, map->l_name,
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"cannot allocate symbol search list");
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map->l_searchlist.r_nlist = nlist;
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for (nlist = 0, runp = known; runp; runp = runp->unique)
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{
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if (trace_mode && runp->map->l_opencount == 0)
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/* This can happen when we trace the loading. */
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--map->l_searchlist.r_nlist;
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else
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map->l_searchlist.r_list[nlist++] = runp->map;
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/* Now clear all the mark bits we set in the objects on the search list
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to avoid duplicates, so the next call starts fresh. */
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runp->map->l_reserved = 0;
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}
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map->l_searchlist.r_nduplist = nduplist;
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if (nlist == nduplist)
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map->l_searchlist.r_duplist = map->l_searchlist.r_list;
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else
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{
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unsigned int cnt;
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map->l_searchlist.r_duplist = malloc (nduplist
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* sizeof (struct link_map *));
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if (map->l_searchlist.r_duplist == NULL)
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_dl_signal_error (ENOMEM, map->l_name,
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"cannot allocate symbol search list");
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for (cnt = 0, runp = known; runp; runp = runp->dup)
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if (trace_mode && runp->map->l_opencount == 0)
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/* This can happen when we trace the loading. */
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--map->l_searchlist.r_nduplist;
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else
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map->l_searchlist.r_duplist[cnt++] = runp->map;
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}
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}
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