/* Copyright (C) 2002 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, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include <errno.h> #include <fcntl.h> #include <semaphore.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> static void remove_sem (int status, void *arg) { sem_unlink (arg); } int main (void) { sem_t *s; sem_t *s2; pid_t pid; int val; s = sem_open ("/glibc-tst-sem4", O_CREAT, 0600, 1); if (s == SEM_FAILED) { if (errno == ENOSYS) { puts ("sem_open not supported. Oh well."); return 0; } /* Maybe the shm filesystem has strict permissions. */ if (errno == EACCES) { puts ("sem_open not allowed. Oh well."); return 0; } printf ("sem_open: %m\n"); return 1; } on_exit (remove_sem, (void *) "/glibc-tst-sem4"); /* We have the semaphore object. Now try again with O_EXCL, this should fail. */ s2 = sem_open ("/glibc-tst-sem4", O_CREAT | O_EXCL, 0600, 1); if (s2 != SEM_FAILED) { puts ("2nd sem_open didn't fail"); return 1; } if (errno != EEXIST) { puts ("2nd sem_open returned wrong error"); return 1; } /* Check the value. */ if (sem_getvalue (s, &val) == -1) { puts ("getvalue failed"); return 1; } if (val != 1) { printf ("initial value wrong: got %d, expected 1\n", val); return 1; } if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1) { puts ("1st sem_wait failed"); return 1; } pid = fork (); if (pid == -1) { printf ("fork failed: %m\n"); return 1; } if (pid == 0) { /* Child. */ /* Check the value. */ if (sem_getvalue (s, &val) == -1) { puts ("child: getvalue failed"); return 1; } if (val != 0) { printf ("child: value wrong: got %d, expect 0\n", val); return 1; } if (sem_post (s) == -1) { puts ("child: post failed"); return 1; } } else { if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1) { puts ("2nd sem_wait failed"); return 1; } if (sem_getvalue (s, &val) == -1) { puts ("parent: 2nd getvalue failed"); return 1; } if (val != 0) { printf ("parent: value wrong: got %d, expected 0\n", val); return 1; } } return 0; }