1  /* Copyright (C) 2002-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <pthread.h>
      19  #include <stdio.h>
      20  #include <stdlib.h>
      21  #include <unistd.h>
      22  #include <sys/file.h>
      23  
      24  #include <support/xunistd.h>
      25  
      26  static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
      27  
      28  static int fd;
      29  
      30  
      31  static void *
      32  tf (void *arg)
      33  {
      34    if (flock (fd, LOCK_SH | LOCK_NB) != 0)
      35      {
      36        puts ("second flock failed");
      37        exit (1);
      38      }
      39  
      40    pthread_mutex_unlock (&lock);
      41  
      42    return NULL;
      43  }
      44  
      45  
      46  static int
      47  do_test (void)
      48  {
      49    char tmp[] = "/tmp/tst-flock1-XXXXXX";
      50  
      51    fd = mkstemp (tmp);
      52    if (fd == -1)
      53      {
      54        puts ("mkstemp failed");
      55        exit (1);
      56      }
      57  
      58    unlink (tmp);
      59  
      60    xwrite (fd, "foobar xyzzy", 12);
      61  
      62    if (flock (fd, LOCK_EX | LOCK_NB) != 0)
      63      {
      64        puts ("first flock failed");
      65        exit (1);
      66      }
      67  
      68    pthread_mutex_lock (&lock);
      69  
      70    pthread_t th;
      71    if (pthread_create (&th, NULL, tf, NULL) != 0)
      72      {
      73        puts ("pthread_create failed");
      74        exit (1);
      75      }
      76  
      77    pthread_mutex_lock (&lock);
      78  
      79    void *result;
      80    if (pthread_join (th, &result) != 0)
      81      {
      82        puts ("pthread_join failed");
      83        exit (1);
      84      }
      85  
      86    close (fd);
      87  
      88    return result != NULL;
      89  }
      90  
      91  #define TEST_FUNCTION do_test ()
      92  #include "../test-skeleton.c"