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/* Look up a symbol in a shared object loaded by `dlopen'.
Copyright (C) 1995, 1996, 1997, 1998, 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 <dlfcn.h>
#include <setjmp.h>
#include <stddef.h>
#include <elf/ldsodefs.h>
struct dlsym_args
{
/* The arguments to dlsym_doit. */
void *handle;
const char *name;
struct r_found_version version;
ElfW(Addr) caller;
/* The return values of dlsym_doit. */
ElfW(Addr) loadbase;
const ElfW(Sym) *ref;
};
static void
dlsym_doit (void *a)
{
struct dlsym_args *args = (struct dlsym_args *) a;
args->ref = NULL;
if (args->handle == RTLD_DEFAULT)
/* Search the global scope. */
args->loadbase = _dl_lookup_symbol (args->name, &args->ref,
_dl_global_scope, NULL, 0);
else if (args->handle == RTLD_NEXT)
{
struct link_map *l, *match;
/* Find the highest-addressed object that CALLER is not below. */
match = NULL;
for (l = _dl_loaded; l; l = l->l_next)
if (args->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;
args->loadbase = _dl_lookup_symbol_skip (args->name, &args->ref,
l->l_local_scope, NULL, match);
if (args->loadbase == 0)
{
/* This means that no such symbol is defined. In this case we
have to provide a phony Elfxx_Sym entry since the value is
referenced in `dlsym'. */
static const ElfW(Sym) null_result;
args->ref = &null_result;
}
}
else
{
/* Search the scope of the given object. */
struct link_map *map = args->handle;
args->loadbase = _dl_lookup_symbol (args->name, &args->ref,
map->l_local_scope, map->l_name, 0);
}
}
void *
dlsym (void *handle, const char *name)
{
struct dlsym_args args;
args.caller = (ElfW(Addr)) __builtin_return_address (0);
args.handle = handle;
args.name = name;
return (_dlerror_run (dlsym_doit, &args)
? NULL : (void *) (args.loadbase + args.ref->st_value));
}
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