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/* Look up a symbol in a shared object loaded by `dlopen'.
Copyright (C) 1995-2019 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 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, see
<https://www.gnu.org/licenses/>. */
#include <dlfcn.h>
#include <stddef.h>
#include <ldsodefs.h>
#if !defined SHARED && IS_IN (libdl)
void *
dlsym (void *handle, const char *name)
{
return __dlsym (handle, name, RETURN_ADDRESS (0));
}
#else
struct dlsym_args
{
/* The arguments to dlsym_doit. */
void *handle;
const char *name;
void *who;
/* The return value of dlsym_doit. */
void *sym;
};
static void
dlsym_doit (void *a)
{
struct dlsym_args *args = (struct dlsym_args *) a;
args->sym = _dl_sym (args->handle, args->name, args->who);
}
void *
__dlsym (void *handle, const char *name DL_CALLER_DECL)
{
# ifdef SHARED
if (!rtld_active ())
return _dlfcn_hook->dlsym (handle, name, DL_CALLER);
# endif
struct dlsym_args args;
args.who = DL_CALLER;
args.handle = handle;
args.name = name;
/* Protect against concurrent loads and unloads. */
__rtld_lock_lock_recursive (GL(dl_load_lock));
void *result = (_dlerror_run (dlsym_doit, &args) ? NULL : args.sym);
__rtld_lock_unlock_recursive (GL(dl_load_lock));
return result;
}
# ifdef SHARED
strong_alias (__dlsym, dlsym)
# endif
#endif
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