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glibc/elf/dl-libc.c
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/* Handle loading and unloading shared objects for internal libc purposes. | |
Copyright (C) 1999, 2000 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 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 <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) _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; | |
/* 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, RTLD_LAZY, NULL); | |
} | |
static void | |
do_dlsym (void *ptr) | |
{ | |
struct do_dlsym_args *args = (struct do_dlsym_args *) ptr; | |
args->ref = NULL; | |
args->loadbase = _dl_lookup_symbol (args->name, args->map, &args->ref, | |
args->map->l_local_scope, 0, 1); | |
} | |
static void | |
do_dlclose (void *ptr) | |
{ | |
_dl_close ((struct link_map *) ptr); | |
} | |
/* ... and these functions call dlerror_run. */ | |
void * | |
__libc_dlopen (const char *__name) | |
{ | |
struct do_dlopen_args args; | |
args.name = __name; | |
return (dlerror_run (do_dlopen, &args) ? NULL : (void *) args.map); | |
} | |
void * | |
__libc_dlsym (void *__map, const char *__name) | |
{ | |
struct do_dlsym_args args; | |
args.map = __map; | |
args.name = __name; | |
return (dlerror_run (do_dlsym, &args) ? NULL | |
: (void *) (DL_SYMBOL_ADDRESS (args.loadbase, args.ref))); | |
} | |
int | |
__libc_dlclose (void *__map) | |
{ | |
return dlerror_run (do_dlclose, __map); | |
} | |
static void | |
free_mem (void) | |
{ | |
struct link_map *l; | |
/* Remove all additional names added to the objects. */ | |
for (l = _dl_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); | |
} | |
} | |
} | |
text_set_element (__libc_subfreeres, free_mem); |