Permalink
Cannot retrieve contributors at this time
Name already in use
A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
glibc/elf/dl-libc.c
Go to fileThis commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
247 lines (208 sloc)
6.28 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/* Handle loading and unloading shared objects for internal libc purposes. | |
Copyright (C) 1999, 2000, 2001, 2002, 2004 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
Contributed by Zack Weinberg <zack@rabi.columbia.edu>, 1999. | |
The GNU C Library is free software; you can redistribute it and/or | |
modify it under the terms of the GNU Lesser General Public | |
License as published by the Free Software Foundation; either | |
version 2.1 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 | |
Lesser General Public License for more details. | |
You should have received a copy of the GNU Lesser General Public | |
License along with the GNU C Library; if not, write to the Free | |
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
02111-1307 USA. */ | |
#include <dlfcn.h> | |
#include <stdlib.h> | |
#include <ldsodefs.h> | |
/* The purpose of this file is to provide wrappers around the dynamic | |
linker error mechanism (similar to dlopen() et al in libdl) which | |
are usable from within libc. Generally we want to throw away the | |
string that dlerror() would return and just pass back a null pointer | |
for errors. This also lets the rest of libc not know about the error | |
handling mechanism. | |
Much of this code came from gconv_dl.c with slight modifications. */ | |
static int | |
internal_function | |
dlerror_run (void (*operate) (void *), void *args) | |
{ | |
const char *objname; | |
const char *last_errstring = NULL; | |
int result; | |
(void) GLRO(dl_catch_error) (&objname, &last_errstring, operate, args); | |
result = last_errstring != NULL; | |
if (result && last_errstring != _dl_out_of_memory) | |
free ((char *) last_errstring); | |
return result; | |
} | |
/* These functions are called by dlerror_run... */ | |
struct do_dlopen_args | |
{ | |
/* Argument to do_dlopen. */ | |
const char *name; | |
/* Opening mode. */ | |
int mode; | |
/* Return from do_dlopen. */ | |
struct link_map *map; | |
}; | |
struct do_dlsym_args | |
{ | |
/* Arguments to do_dlsym. */ | |
struct link_map *map; | |
const char *name; | |
/* Return values of do_dlsym. */ | |
lookup_t loadbase; | |
const ElfW(Sym) *ref; | |
}; | |
static void | |
do_dlopen (void *ptr) | |
{ | |
struct do_dlopen_args *args = (struct do_dlopen_args *) ptr; | |
/* Open and relocate the shared object. */ | |
args->map = _dl_open (args->name, args->mode, NULL, __LM_ID_CALLER); | |
} | |
static void | |
do_dlsym (void *ptr) | |
{ | |
struct do_dlsym_args *args = (struct do_dlsym_args *) ptr; | |
args->ref = NULL; | |
args->loadbase = GLRO(dl_lookup_symbol_x) (args->name, args->map, &args->ref, | |
args->map->l_local_scope, NULL, 0, | |
DL_LOOKUP_RETURN_NEWEST, NULL); | |
} | |
static void | |
do_dlclose (void *ptr) | |
{ | |
_dl_close ((struct link_map *) ptr); | |
} | |
/* This code is to support __libc_dlopen from __libc_dlopen'ed shared | |
libraries. We need to ensure the statically linked __libc_dlopen | |
etc. functions are used instead of the dynamically loaded. */ | |
struct dl_open_hook | |
{ | |
void *(*dlopen_mode) (const char *name, int mode); | |
void *(*dlsym) (void *map, const char *name); | |
int (*dlclose) (void *map); | |
}; | |
#ifdef SHARED | |
extern struct dl_open_hook *_dl_open_hook; | |
libc_hidden_proto (_dl_open_hook); | |
struct dl_open_hook *_dl_open_hook __attribute__((nocommon)); | |
libc_hidden_data_def (_dl_open_hook); | |
#else | |
static void | |
do_dlsym_private (void *ptr) | |
{ | |
lookup_t l; | |
struct r_found_version vers; | |
vers.name = "GLIBC_PRIVATE"; | |
vers.hidden = 1; | |
/* vers.hash = _dl_elf_hash (version); */ | |
vers.hash = 0x0963cf85; | |
vers.filename = NULL; | |
struct do_dlsym_args *args = (struct do_dlsym_args *) ptr; | |
args->ref = NULL; | |
l = GLRO(dl_lookup_symbol_x) (args->name, args->map, &args->ref, | |
args->map->l_scope, &vers, 0, 0, NULL); | |
args->loadbase = l; | |
} | |
static struct dl_open_hook _dl_open_hook = | |
{ | |
.dlopen_mode = __libc_dlopen_mode, | |
.dlsym = __libc_dlsym, | |
.dlclose = __libc_dlclose | |
}; | |
#endif | |
/* ... and these functions call dlerror_run. */ | |
void * | |
__libc_dlopen_mode (const char *name, int mode) | |
{ | |
struct do_dlopen_args args; | |
args.name = name; | |
args.mode = mode; | |
#ifdef SHARED | |
if (__builtin_expect (_dl_open_hook != NULL, 0)) | |
return _dl_open_hook->dlopen_mode (name, mode); | |
return (dlerror_run (do_dlopen, &args) ? NULL : (void *) args.map); | |
#else | |
if (dlerror_run (do_dlopen, &args)) | |
return NULL; | |
__libc_register_dl_open_hook (args.map); | |
__libc_register_dlfcn_hook (args.map); | |
return (void *) args.map; | |
#endif | |
} | |
libc_hidden_def (__libc_dlopen_mode) | |
#ifndef SHARED | |
void * | |
__libc_dlsym_private (struct link_map *map, const char *name) | |
{ | |
struct do_dlsym_args sargs; | |
sargs.map = map; | |
sargs.name = name; | |
if (! dlerror_run (do_dlsym_private, &sargs)) | |
return DL_SYMBOL_ADDRESS (sargs.loadbase, sargs.ref); | |
return NULL; | |
} | |
void | |
__libc_register_dl_open_hook (struct link_map *map) | |
{ | |
struct dl_open_hook **hook; | |
hook = (struct dl_open_hook **) __libc_dlsym_private (map, "_dl_open_hook"); | |
if (hook != NULL) | |
*hook = &_dl_open_hook; | |
} | |
#endif | |
void * | |
__libc_dlsym (void *map, const char *name) | |
{ | |
struct do_dlsym_args args; | |
args.map = map; | |
args.name = name; | |
#ifdef SHARED | |
if (__builtin_expect (_dl_open_hook != NULL, 0)) | |
return _dl_open_hook->dlsym (map, name); | |
#endif | |
return (dlerror_run (do_dlsym, &args) ? NULL | |
: (void *) (DL_SYMBOL_ADDRESS (args.loadbase, args.ref))); | |
} | |
libc_hidden_def (__libc_dlsym) | |
int | |
__libc_dlclose (void *map) | |
{ | |
#ifdef SHARED | |
if (__builtin_expect (_dl_open_hook != NULL, 0)) | |
return _dl_open_hook->dlclose (map); | |
#endif | |
return dlerror_run (do_dlclose, map); | |
} | |
libc_hidden_def (__libc_dlclose) | |
libc_freeres_fn (free_mem) | |
{ | |
struct link_map *l; | |
struct r_search_path_elem *d; | |
/* Remove all search directories. */ | |
d = GL(dl_all_dirs); | |
while (d != GLRO(dl_init_all_dirs)) | |
{ | |
struct r_search_path_elem *old = d; | |
d = d->next; | |
free (old); | |
} | |
/* Remove all additional names added to the objects. */ | |
for (Lmid_t ns = 0; ns < DL_NNS; ++ns) | |
for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next) | |
{ | |
struct libname_list *lnp = l->l_libname->next; | |
l->l_libname->next = NULL; | |
while (lnp != NULL) | |
{ | |
struct libname_list *old = lnp; | |
lnp = lnp->next; | |
if (! old->dont_free) | |
free (old); | |
} | |
} | |
} |