binutils-gdb/gdb/compile/compile-object-run.c
Jan Kratochvil 7f36105668 compile: Use also inferior munmap
Currently inferior memory is allocated by inferior mmap() but it is never
deallocated; despite the injected objfile incl. its symbols is freed.  This was
intentional so that one can do for example:
inferior:
	char *str = "foo";
GDB:
	(gdb) compile code str = "bar";

I believe later patches will be needed to introduce full control over keeping
vs. discarding the injected module as being discussed in:
	compile: objfiles lifetime UI
	https://sourceware.org/ml/gdb/2015-04/msg00051.html
	Message-ID: <20150429135735.GA16974@host1.jankratochvil.net>
	https://sourceware.org/ml/gdb/2015-05/msg00007.html

As decided by Phil it is better not to leak inferior pages as users can
workaround the issue above for example by:
	(gdb) compile code str = strdup ("bar");

I have checked that in fact gdb/doc/ (written by Phil) already expects the
injected code will be unmapped so that does not need to be changed:
	compile code int ff = 5; p = &ff;
	In this example, @code{p} would point to @code{ff} when the
	@code{compile} command is executing the source code provided to it.
	However, as variables in the (example) program persist with their
	assigned values, the variable @code{p} would point to an invalid
	location when the command exists.

gdb/ChangeLog
2015-04-28  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* arch-utils.c (default_infcall_munmap): New.
	* arch-utils.h (default_infcall_munmap): New declaration.
	* compile/compile-object-load.c (struct munmap_list, munmap_list_add)
	(munmap_list_free, munmap_listp_free_cleanup): New.
	(struct setup_sections_data): Add field munmap_list_headp.
	(setup_sections): Call munmap_list_add.
	(compile_object_load): New variable munmap_list_head, initialize
	setup_sections_data.munmap_list_headp, return munmap_list_head.
	* compile/compile-object-load.h (struct munmap_list): New declaration.
	(struct compile_module): Add field munmap_list_head.
	(munmap_list_free): New declaration.
	* compile/compile-object-run.c (struct do_module_cleanup): Add field
	munmap_list_head.
	(do_module_cleanup): Call munmap_list_free.
	(compile_object_run): Pass munmap_list_head to do_module_cleanup.
	* gdbarch.c: Regenerate.
	* gdbarch.h: Regenerate.
	* gdbarch.sh (infcall_munmap): New.
	* linux-tdep.c (linux_infcall_munmap): New.
	(linux_init_abi): Install it.

gdb/testsuite/ChangeLog
2015-04-28  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.compile/compile.exp (keep jit in memory): Rename to ...
	(do not keep jit in memory): ... this.
	(expect 5): Change it to ...
	(expect no 5): ... this.
2015-06-03 21:26:04 +02:00

194 lines
5.9 KiB
C

/* Call module for 'compile' command.
Copyright (C) 2014-2015 Free Software Foundation, Inc.
This file is part of GDB.
This program 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 of the License, 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. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "compile-object-run.h"
#include "value.h"
#include "infcall.h"
#include "objfiles.h"
#include "compile-internal.h"
#include "dummy-frame.h"
#include "block.h"
#include "valprint.h"
#include "compile.h"
/* Helper for do_module_cleanup. */
struct do_module_cleanup
{
/* Boolean to set true upon a call of do_module_cleanup.
The pointer may be NULL. */
int *executedp;
/* .c file OBJFILE was built from. It needs to be xfree-d. */
char *source_file;
/* Copy from struct compile_module. */
enum compile_i_scope_types scope;
void *scope_data;
/* Copy from struct compile_module. */
struct type *out_value_type;
CORE_ADDR out_value_addr;
/* Copy from struct compile_module. */
struct munmap_list *munmap_list_head;
/* objfile_name of our objfile. */
char objfile_name_string[1];
};
/* Cleanup everything after the inferior function dummy frame gets
discarded. */
static dummy_frame_dtor_ftype do_module_cleanup;
static void
do_module_cleanup (void *arg, int registers_valid)
{
struct do_module_cleanup *data = arg;
struct objfile *objfile;
if (data->executedp != NULL)
{
*data->executedp = 1;
/* This code cannot be in compile_object_run as OUT_VALUE_TYPE
no longer exists there. */
if (data->scope == COMPILE_I_PRINT_ADDRESS_SCOPE
|| data->scope == COMPILE_I_PRINT_VALUE_SCOPE)
{
struct value *addr_value;
struct type *ptr_type = lookup_pointer_type (data->out_value_type);
addr_value = value_from_pointer (ptr_type, data->out_value_addr);
/* SCOPE_DATA would be stale unlesse EXECUTEDP != NULL. */
compile_print_value (value_ind (addr_value), data->scope_data);
}
}
ALL_OBJFILES (objfile)
if ((objfile->flags & OBJF_USERLOADED) == 0
&& (strcmp (objfile_name (objfile), data->objfile_name_string) == 0))
{
free_objfile (objfile);
/* It may be a bit too pervasive in this dummy_frame dtor callback. */
clear_symtab_users (0);
break;
}
/* Delete the .c file. */
unlink (data->source_file);
xfree (data->source_file);
munmap_list_free (data->munmap_list_head);
/* Delete the .o file. */
unlink (data->objfile_name_string);
xfree (data);
}
/* Perform inferior call of MODULE. This function may throw an error.
This function may leave files referenced by MODULE on disk until
the inferior call dummy frame is discarded. This function may throw errors.
Thrown errors and left MODULE files are unrelated events. Caller must no
longer touch MODULE's memory after this function has been called. */
void
compile_object_run (struct compile_module *module)
{
struct value *func_val;
struct frame_id dummy_id;
struct cleanup *cleanups;
struct do_module_cleanup *data;
const char *objfile_name_s = objfile_name (module->objfile);
int dtor_found, executed = 0;
struct symbol *func_sym = module->func_sym;
CORE_ADDR regs_addr = module->regs_addr;
struct objfile *objfile = module->objfile;
data = xmalloc (sizeof (*data) + strlen (objfile_name_s));
data->executedp = &executed;
data->source_file = xstrdup (module->source_file);
strcpy (data->objfile_name_string, objfile_name_s);
data->scope = module->scope;
data->scope_data = module->scope_data;
data->out_value_type = module->out_value_type;
data->out_value_addr = module->out_value_addr;
data->munmap_list_head = module->munmap_list_head;
xfree (module->source_file);
xfree (module);
module = NULL;
TRY
{
struct type *func_type = SYMBOL_TYPE (func_sym);
htab_t copied_types;
int current_arg = 0;
struct value **vargs;
/* OBJFILE may disappear while FUNC_TYPE still will be in use. */
copied_types = create_copied_types_hash (objfile);
func_type = copy_type_recursive (objfile, func_type, copied_types);
htab_delete (copied_types);
gdb_assert (TYPE_CODE (func_type) == TYPE_CODE_FUNC);
func_val = value_from_pointer (lookup_pointer_type (func_type),
BLOCK_START (SYMBOL_BLOCK_VALUE (func_sym)));
vargs = alloca (sizeof (*vargs) * TYPE_NFIELDS (func_type));
if (TYPE_NFIELDS (func_type) >= 1)
{
gdb_assert (regs_addr != 0);
vargs[current_arg] = value_from_pointer
(TYPE_FIELD_TYPE (func_type, current_arg), regs_addr);
++current_arg;
}
if (TYPE_NFIELDS (func_type) >= 2)
{
gdb_assert (data->out_value_addr != 0);
vargs[current_arg] = value_from_pointer
(TYPE_FIELD_TYPE (func_type, current_arg), data->out_value_addr);
++current_arg;
}
gdb_assert (current_arg == TYPE_NFIELDS (func_type));
call_function_by_hand_dummy (func_val, TYPE_NFIELDS (func_type), vargs,
do_module_cleanup, data);
}
CATCH (ex, RETURN_MASK_ERROR)
{
/* In the case of DTOR_FOUND or in the case of EXECUTED nothing
needs to be done. */
dtor_found = find_dummy_frame_dtor (do_module_cleanup, data);
if (!executed)
data->executedp = NULL;
gdb_assert (!(dtor_found && executed));
if (!dtor_found && !executed)
do_module_cleanup (data, 0);
throw_exception (ex);
}
END_CATCH
dtor_found = find_dummy_frame_dtor (do_module_cleanup, data);
gdb_assert (!dtor_found && executed);
}