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/* Load a shared object at runtime, relocate it, and run its initializer.
Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <dlfcn.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h> /* Check whether MAP_COPY is defined. */
#include <bits/libc-lock.h>
#include <elf/ldsodefs.h>
extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
void (*dl_main) (const ElfW(Phdr) *phdr,
ElfW(Word) phnum,
ElfW(Addr) *user_entry));
weak_extern (_dl_sysdep_start)
/* This function is used to unload the cache file if necessary. */
extern void _dl_unload_cache (void);
extern int __libc_multiple_libcs; /* Defined in init-first.c. */
extern int __libc_argc;
extern char **__libc_argv;
extern char **__environ;
/* During the program run we must not modify the global data of
loaded shared object simultanously in two threads. Therefore we
protect `_dl_open' and `_dl_close' in dl-close.c.
This must be a recursive lock since the initializer function of
the loaded object might as well require a call to this function.
At this time it is not anymore a problem to modify the tables. */
__libc_lock_define_initialized_recursive (, _dl_load_lock)
/* We must be carefull not to leave us in an inconsistent state. Thus we
catch any error and re-raise it after cleaning up. */
struct dl_open_args
{
const char *file;
int mode;
struct link_map *map;
};
static void
dl_open_worker (void *a)
{
struct dl_open_args *args = a;
const char *file = args->file;
int mode = args->mode;
struct link_map *new, *l;
ElfW(Addr) init;
struct r_debug *r;
unsigned int global_add;
/* Load the named object. */
args->map = new = _dl_map_object (NULL, file, 0, lt_loaded, 0);
if (new->l_searchlist.r_list)
/* It was already open. */
return;
/* Load that object's dependencies. */
global_add = _dl_map_object_deps (new, NULL, 0, 0, mode & RTLD_GLOBAL);
/* So far, so good. Now check the versions. */
(void) _dl_check_all_versions (new, 0);
/* Relocate the objects loaded. We do this in reverse order so that copy
relocs of earlier objects overwrite the data written by later objects. */
l = new;
while (l->l_next)
l = l->l_next;
while (1)
{
if (! l->l_relocated)
{
#ifdef PIC
if (_dl_profile != NULL)
{
/* If this here is the shared object which we want to profile
make sure the profile is started. We can find out whether
this is necessary or not by observing the `_dl_profile_map'
variable. If was NULL but is not NULL afterwars we must
start the profiling. */
struct link_map *old_profile_map = _dl_profile_map;
_dl_relocate_object (l, l->l_scope, 1, 1);
if (old_profile_map == NULL && _dl_profile_map != NULL)
/* We must prepare the profiling. */
_dl_start_profile (_dl_profile_map, _dl_profile_output);
}
else
#endif
_dl_relocate_object (l, l->l_scope,
(mode & RTLD_BINDING_MASK) == RTLD_LAZY, 0);
}
if (l == new)
break;
l = l->l_prev;
}
/* Notify the debugger we have added some objects. We need to call
_dl_debug_initialize in a static program in case dynamic linking has
not been used before. */
r = _dl_debug_initialize (0);
r->r_state = RT_ADD;
_dl_debug_state ();
/* Run the initializer functions of new objects. */
while ((init = _dl_init_next (&new->l_searchlist)))
(*(void (*) (int, char **, char **)) init) (__libc_argc, __libc_argv,
__environ);
if (new->l_global)
/* Now we can make the new map available in the global scope. */
_dl_main_searchlist->r_nlist += global_add;
if (_dl_sysdep_start == NULL)
/* We must be the static _dl_open in libc.a. A static program that
has loaded a dynamic object now has competition. */
__libc_multiple_libcs = 1;
}
struct link_map *
internal_function
_dl_open (const char *file, int mode)
{
struct dl_open_args args;
char *errstring;
int errcode;
/* Make sure we are alone. */
__libc_lock_lock (_dl_load_lock);
args.file = file;
args.mode = mode;
args.map = NULL;
errcode = _dl_catch_error (&errstring, dl_open_worker, &args);
#ifndef MAP_COPY
/* We must munmap() the cache file. */
_dl_unload_cache ();
#endif
/* Release the lock. */
__libc_lock_unlock (_dl_load_lock);
if (errstring)
{
/* Some error occured during loading. */
char *local_errstring;
/* Remove the object from memory. It may be in an inconsistent
state if relocation failed, for example. */
if (args.map)
_dl_close (args.map);
/* Make a local copy of the error string so that we can release the
memory allocated for it. */
local_errstring = strdupa (errstring);
free (errstring);
/* Reraise the error. */
_dl_signal_error (errcode, NULL, local_errstring);
}
return args.map;
}
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