/* Look up a symbol in a shared object loaded by `dlopen'.

   Copyright (C) 1995-2018 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

   <http://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