/* Copyright (C) 2002-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.

   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 <errno.h>

#include <semaphore.h>

#include <stdint.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/mman.h>

#include <sys/wait.h>

int

do_test (void)

{

  size_t ps = sysconf (_SC_PAGESIZE);

  char tmpfname[] = "/tmp/tst-sem3.XXXXXX";

  char data[ps];

  void *mem;

  int fd;

  sem_t *s;

  pid_t pid;

  char *p;

  fd = mkstemp (tmpfname);

  if (fd == -1)

    {

      printf ("cannot open temporary file: %m\n");

      return 1;

    }

  /* Make sure it is always removed.  */

  unlink (tmpfname);

  /* Create one page of data.  */

  memset (data, '\0', ps);

  /* Write the data to the file.  */

  if (write (fd, data, ps) != (ssize_t) ps)

    {

      puts ("short write");

      return 1;

    }

  mem = mmap (NULL, ps, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);

  if (mem == MAP_FAILED)

    {

      printf ("mmap failed: %m\n");

      return 1;

    }

  s = (sem_t *) (((uintptr_t) mem + __alignof (sem_t))

		 & ~(__alignof (sem_t) - 1));

  p = (char *) (s + 1);

  if (sem_init (s, 1, 1) == -1)

    {

      puts ("init failed");

      return 1;

    }

  if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1)

    {

      puts ("1st wait failed");

      return 1;

    }

  errno = 0;

  if (TEMP_FAILURE_RETRY (sem_trywait (s)) != -1)

    {

      puts ("trywait succeeded");

      return 1;

    }

  else if (errno != EAGAIN)

    {

      puts ("trywait didn't return EAGAIN");

      return 1;

    }

  *p = 0;

  puts ("going to fork now");

  pid = fork ();

  if (pid == -1)

    {

      puts ("fork failed");

      return 1;

    }

  else if (pid == 0)

    {

      /* Play some lock ping-pong.  It's our turn to unlock first.  */

      if ((*p)++ != 0)

	{

	  puts ("child: *p != 0");

	  return 1;

	}

      if (sem_post (s) == -1)

	{

	  puts ("child: 1st post failed");

	  return 1;

	}

      puts ("child done");

    }

  else

    {

      if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1)

	{

	  printf ("parent: 2nd wait failed: %m\n");

	  return 1;

	}

      if (*p != 1)

	{

	  puts ("*p != 1");

	  return 1;

	}

      puts ("parent done");

    }

  return 0;

}

#define TEST_FUNCTION do_test ()

#include "../test-skeleton.c"