glibc/elf/dl-sym.c

138 lines
3.8 KiB
C

/* Look up a symbol in a shared object loaded by `dlopen'.
Copyright (C) 1999 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 <stddef.h>
#include <setjmp.h>
#include <libintl.h>
#include <dlfcn.h>
#include <ldsodefs.h>
#include <dl-hash.h>
void *
internal_function
_dl_sym (void *handle, const char *name, void *who)
{
ElfW(Addr) loadbase;
const ElfW(Sym) *ref = NULL;
if (handle == RTLD_DEFAULT)
/* Search the global scope. */
loadbase = _dl_lookup_symbol (name, NULL, &ref, _dl_global_scope, 0);
else
{
struct link_map *l, *match;
ElfW(Addr) caller = (ElfW(Addr)) who;
/* Find the highest-addressed object that CALLER is not below. */
match = NULL;
for (l = _dl_loaded; l; l = l->l_next)
if (caller >= l->l_addr && (!match || match->l_addr < l->l_addr))
match = l;
if (handle != RTLD_NEXT)
{
/* Search the scope of the given object. */
struct link_map *map = handle;
if (match == NULL)
/* If the address is not recognized the call comes from the
main program (we hope). */
match = _dl_loaded;
loadbase = _dl_lookup_symbol (name, match, &ref, map->l_local_scope,
0);
}
else
{
if (! match)
_dl_signal_error (0, NULL, _("\
RTLD_NEXT used in code not dynamically loaded"));
l = match;
while (l->l_loader)
l = l->l_loader;
loadbase = _dl_lookup_symbol_skip (name, l, &ref, l->l_local_scope,
match);
}
}
if (loadbase)
return (void *) (loadbase + ref->st_value);
return NULL;
}
void *
internal_function
_dl_vsym (void *handle, const char *name, const char *version, void *who)
{
ElfW(Addr) loadbase;
const ElfW(Sym) *ref = NULL;
struct r_found_version vers;
/* Compute hash value to the version string. */
vers.name = version;
vers.hidden = 1;
vers.hash = _dl_elf_hash (version);
/* We don't have a specific file where the symbol can be found. */
vers.filename = NULL;
if (handle == RTLD_DEFAULT)
/* Search the global scope. */
loadbase = _dl_lookup_versioned_symbol (name, NULL, &ref, _dl_global_scope,
&vers, 0);
else if (handle == RTLD_NEXT)
{
struct link_map *l, *match;
ElfW(Addr) caller = (ElfW(Addr)) who;
/* Find the highest-addressed object that CALLER is not below. */
match = NULL;
for (l = _dl_loaded; l; l = l->l_next)
if (caller >= l->l_addr && (!match || match->l_addr < l->l_addr))
match = l;
if (! match)
_dl_signal_error (0, NULL, _("\
RTLD_NEXT used in code not dynamically loaded"));
l = match;
while (l->l_loader)
l = l->l_loader;
loadbase = _dl_lookup_versioned_symbol_skip (name, l, &ref,
l->l_local_scope,
&vers, match);
}
else
{
/* Search the scope of the given object. */
struct link_map *map = handle;
loadbase = _dl_lookup_versioned_symbol (name, map, &ref,
map->l_local_scope, &vers, 0);
}
if (loadbase)
return (void *) (loadbase + ref->st_value);
return NULL;
}