/* 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 <pthread.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/file.h>

#include <sys/mman.h>

#include <sys/wait.h>

static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;

static pthread_mutex_t lock2 = PTHREAD_MUTEX_INITIALIZER;

static int fd;

static void *

tf (void *arg)

{

  struct flock fl =

    {

      .l_type = F_WRLCK,

      .l_start = 0,

      .l_whence = SEEK_SET,

      .l_len = 10

    };

  if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)

    {

      puts ("fourth fcntl failed");

      exit (1);

    }

  pthread_mutex_unlock (&lock);

  pthread_mutex_lock (&lock2);

  return NULL;

}

static int

do_test (void)

{

  char tmp[] = "/tmp/tst-flock2-XXXXXX";

  fd = mkstemp (tmp);

  if (fd == -1)

    {

      puts ("mkstemp failed");

      return 1;

    }

  unlink (tmp);

  int i;

  for (i = 0; i < 20; ++i)

    write (fd, "foobar xyzzy", 12);

  pthread_barrier_t *b;

  b = mmap (NULL, sizeof (pthread_barrier_t), PROT_READ | PROT_WRITE,

	    MAP_SHARED, fd, 0);

  if (b == MAP_FAILED)

    {

      puts ("mmap failed");

      return 1;

    }

  pthread_barrierattr_t ba;

  if (pthread_barrierattr_init (&ba) != 0)

    {

      puts ("barrierattr_init failed");

      return 1;

    }

  if (pthread_barrierattr_setpshared (&ba, PTHREAD_PROCESS_SHARED) != 0)

    {

      puts ("barrierattr_setpshared failed");

      return 1;

    }

  if (pthread_barrier_init (b, &ba, 2) != 0)

    {

      puts ("barrier_init failed");

      return 1;

    }

  if (pthread_barrierattr_destroy (&ba) != 0)

    {

      puts ("barrierattr_destroy failed");

      return 1;

    }

  struct flock fl =

    {

      .l_type = F_WRLCK,

      .l_start = 0,

      .l_whence = SEEK_SET,

      .l_len = 10

    };

  if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)

    {

      puts ("first fcntl failed");

      return 1;

    }

  pid_t pid = fork ();

  if (pid == -1)

    {

      puts ("fork failed");

      return 1;

    }

  if (pid == 0)

    {

      /* Make sure the child does not stay around indefinitely.  */

      alarm (10);

      /* Try to get the lock.  */

      if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0)

	{

	  puts ("child:  second flock succeeded");

	  return 1;

	}

    }

  pthread_barrier_wait (b);

  if (pid != 0)

    {

      fl.l_type = F_UNLCK;

      if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)

	{

	  puts ("third fcntl failed");

	  return 1;

	}

    }

  pthread_barrier_wait (b);

  pthread_t th;

  if (pid == 0)

    {

      if (pthread_mutex_lock (&lock) != 0)

	{

	  puts ("1st locking of lock failed");

	  return 1;

	}

      if (pthread_mutex_lock (&lock2) != 0)

	{

	  puts ("1st locking of lock2 failed");

	  return 1;

	}

      if (pthread_create (&th, NULL, tf, NULL) != 0)

	{

	  puts ("pthread_create failed");

	  return 1;

	}

      if (pthread_mutex_lock (&lock) != 0)

	{

	  puts ("2nd locking of lock failed");

	  return 1;

	}

      puts ("child locked file");

    }

  pthread_barrier_wait (b);

  if (pid != 0)

    {

      fl.l_type = F_WRLCK;

      if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0)

	{

	  puts ("fifth fcntl succeeded");

	  return 1;

	}

      puts ("file locked by child");

    }

  pthread_barrier_wait (b);

  if (pid == 0)

    {

      if (pthread_mutex_unlock (&lock2) != 0)

	{

	  puts ("unlock of lock2 failed");

	  return 1;

	}

      if (pthread_join (th, NULL) != 0)

	{

	  puts ("join failed");

	  return 1;

	}

      puts ("child's thread terminated");

    }

  pthread_barrier_wait (b);

  if (pid != 0)

    {

      fl.l_type = F_WRLCK;

      if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0)

	{

	  puts ("fifth fcntl succeeded");

	  return 1;

	}

      puts ("file still locked");

    }

  pthread_barrier_wait (b);

  if (pid == 0)

    {

      _exit (0);

    }

  int status;

  if (TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)) != pid)

    {

      puts ("waitpid failed");

      return 1;

    }

  puts ("child terminated");

  if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)

    {

      puts ("sixth fcntl failed");

      return 1;

    }

  return status;

}

#define TEST_FUNCTION do_test ()

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