nptl/tst-sem4.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 <errno.h>
  20 #include <fcntl.h>
  21 #include <semaphore.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25
  26
  27 static void
  28 remove_sem (int status, void *arg)
  29 {
  30   sem_unlink (arg);
  31 }
  32
  33
  34 int
  35 do_test (void)
  36 {
  37   sem_t *s;
  38   sem_t *s2;
  39   pid_t pid;
  40   int val;
  41
  42   /* Start with a clean slate and register a clean-up action.  No need to
  43      act if sem_unlink fails because we will catch the same problem during the
  44      sem_open below.  */
  45   sem_unlink ("/glibc-tst-sem4");
  46   on_exit (remove_sem, (void *) "/glibc-tst-sem4");
  47
  48   s = sem_open ("/glibc-tst-sem4", O_CREAT, 0600, 1);
  49   if (s == SEM_FAILED)
  50     {
  51       if (errno == ENOSYS)
  52         {
  53           puts ("sem_open not supported.  Oh well.");
  54           return 0;
  55         }
  56
  57       /* Maybe the shm filesystem has strict permissions.  */
  58       if (errno == EACCES)
  59         {
  60           puts ("sem_open not allowed.  Oh well.");
  61           return 0;
  62         }
  63
  64       printf ("sem_open: %m\n");
  65       return 1;
  66     }
  67
  68   /* We have the semaphore object.  Now try again with O_EXCL, this
  69      should fail.  */
  70   s2 = sem_open ("/glibc-tst-sem4", O_CREAT | O_EXCL, 0600, 1);
  71   if (s2 != SEM_FAILED)
  72     {
  73       puts ("2nd sem_open didn't fail");
  74       return 1;
  75     }
  76   if (errno != EEXIST)
  77     {
  78       puts ("2nd sem_open returned wrong error");
  79       return 1;
  80     }
  81
  82   /* Check the value.  */
  83   if (sem_getvalue (s, &val) == -1)
  84     {
  85       puts ("getvalue failed");
  86       return 1;
  87     }
  88   if (val != 1)
  89     {
  90       printf ("initial value wrong: got %d, expected 1\n", val);
  91       return 1;
  92     }
  93
  94   if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1)
  95     {
  96       puts ("1st sem_wait failed");
  97       return 1;
  98     }
  99
 100   pid = fork ();
 101   if (pid == -1)
 102     {
 103       printf ("fork failed: %m\n");
 104       return 1;
 105     }
 106
 107   if (pid == 0)
 108     {
 109       /* Child.  */
 110
 111       /* Check the value.  */
 112       if (sem_getvalue (s, &val) == -1)
 113         {
 114           puts ("child: getvalue failed");
 115           return 1;
 116         }
 117       if (val != 0)
 118         {
 119           printf ("child: value wrong: got %d, expect 0\n", val);
 120           return 1;
 121         }
 122
 123       if (sem_post (s) == -1)
 124         {
 125           puts ("child: post failed");
 126           return 1;
 127         }
 128     }
 129   else
 130     {
 131       if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1)
 132         {
 133           puts ("2nd sem_wait failed");
 134           return 1;
 135         }
 136
 137       if (sem_getvalue (s, &val) == -1)
 138         {
 139           puts ("parent: 2nd getvalue failed");
 140           return 1;
 141         }
 142       if (val != 0)
 143         {
 144           printf ("parent: value wrong: got %d, expected 0\n", val);
 145           return 1;
 146         }
 147     }
 148
 149   return 0;
 150 }
 151
 152 #define TEST_FUNCTION do_test ()
 153 #include "../test-skeleton.c"