nptl/tst-sem4.c

   1 /* Copyright (C) 2002 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <semaphore.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <unistd.h>
  26
  27
  28 static void
  29 remove_sem (int status, void *arg)
  30 {
  31   sem_unlink (arg);
  32 }
  33
  34
  35 int
  36 main (void)
  37 {
  38   sem_t *s;
  39   sem_t *s2;
  40   pid_t pid;
  41   int val;
  42
  43   s = sem_open ("/glibc-tst-sem4", O_CREAT, 0600, 1);
  44   if (s == SEM_FAILED)
  45     {
  46       if (errno == ENOSYS)
  47         {
  48           puts ("sem_open not supported.  Oh well.");
  49           return 0;
  50         }
  51
  52       /* Maybe the shm filesystem has strict permissions.  */
  53       if (errno == EACCES)
  54         {
  55           puts ("sem_open not allowed.  Oh well.");
  56           return 0;
  57         }
  58
  59       printf ("sem_open: %m\n");
  60       return 1;
  61     }
  62
  63   on_exit (remove_sem, (void *) "/glibc-tst-sem4");
  64
  65   /* We have the semaphore object.  Now try again with O_EXCL, this
  66      should fail.  */
  67   s2 = sem_open ("/glibc-tst-sem4", O_CREAT | O_EXCL, 0600, 1);
  68   if (s2 != SEM_FAILED)
  69     {
  70       puts ("2nd sem_open didn't fail");
  71       return 1;
  72     }
  73   if (errno != EEXIST)
  74     {
  75       puts ("2nd sem_open returned wrong error");
  76       return 1;
  77     }
  78
  79   /* Check the value.  */
  80   if (sem_getvalue (s, &val) == -1)
  81     {
  82       puts ("getvalue failed");
  83       return 1;
  84     }
  85   if (val != 1)
  86     {
  87       printf ("initial value wrong: got %d, expected 1\n", val);
  88       return 1;
  89     }
  90
  91   if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1)
  92     {
  93       puts ("1st sem_wait failed");
  94       return 1;
  95     }
  96
  97   pid = fork ();
  98   if (pid == -1)
  99     {
 100       printf ("fork failed: %m\n");
 101       return 1;
 102     }
 103
 104   if (pid == 0)
 105     {
 106       /* Child.  */
 107
 108       /* Check the value.  */
 109       if (sem_getvalue (s, &val) == -1)
 110         {
 111           puts ("child: getvalue failed");
 112           return 1;
 113         }
 114       if (val != 0)
 115         {
 116           printf ("child: value wrong: got %d, expect 0\n", val);
 117           return 1;
 118         }
 119
 120       if (sem_post (s) == -1)
 121         {
 122           puts ("child: post failed");
 123           return 1;
 124         }
 125     }
 126   else
 127     {
 128       if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1)
 129         {
 130           puts ("2nd sem_wait failed");
 131           return 1;
 132         }
 133
 134       if (sem_getvalue (s, &val) == -1)
 135         {
 136           puts ("parent: 2nd getvalue failed");
 137           return 1;
 138         }
 139       if (val != 0)
 140         {
 141           printf ("parent: value wrong: got %d, expected 0\n", val);
 142           return 1;
 143         }
 144     }
 145
 146   return 0;
 147 }