nptl/tst-flock1.c

   1 /* Copyright (C) 2002-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <pthread.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <unistd.h>
  23 #include <sys/file.h>
  24
  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   write (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"