/* Helper for exit/dlclose race test (Bug 22180).

   Copyright (C) 2017-2018 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 <stdio.h>

#include <stdbool.h>

#include <stdlib.h>

#include <semaphore.h>

#include <unistd.h>

#include <support/check.h>

#include <support/xthread.h>

/* Semaphore defined in executable to ensure we have a happens-before

   between the first function starting and exit being called.  */

extern sem_t order1;

/* Semaphore defined in executable to ensure we have a happens-before

   between the second function starting and the first function returning.  */

extern sem_t order2;

/* glibc function for registering DSO-specific exit functions.  */

extern int __cxa_atexit (void (*func) (void *), void *arg, void *dso_handle);

/* Hidden compiler handle to this shared object.  */

extern void *__dso_handle __attribute__ ((__weak__));

static void

first (void *start)

{

  /* Let the exiting thread run.  */

  sem_post (&order1;;

  /* Wait for exiting thread to finish.  */

  sem_wait (&order2;;

  printf ("first\n");

}

static void

second (void *start)

{

  /* We may be called from different threads.

     This lock protects called.  */

  static pthread_mutex_t mtx = PTHREAD_MUTEX_INITIALIZER;

  static bool called = false;

  xpthread_mutex_lock (&mtx);

  if (called)

    FAIL_EXIT1 ("second called twice!");

  called = true;

  xpthread_mutex_unlock (&mtx);

  printf ("second\n");

}

__attribute__ ((constructor)) static void

constructor (void)

{

  sem_init (&order1, 0, 0);

  sem_init (&order2, 0, 0);

  __cxa_atexit (second, NULL, __dso_handle);

  __cxa_atexit (first, NULL, __dso_handle);

}