diff options
Diffstat (limited to 'nptl/tst-sem3.c')
-rw-r--r-- | nptl/tst-sem3.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/nptl/tst-sem3.c b/nptl/tst-sem3.c new file mode 100644 index 0000000000..7d3f68f019 --- /dev/null +++ b/nptl/tst-sem3.c @@ -0,0 +1,142 @@ +/* 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 <semaphore.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/mman.h> +#include <sys/wait.h> + + +int +main (void) +{ + size_t ps = sysconf (_SC_PAGESIZE); + char tmpfname[] = "/tmp/tst-sem3.XXXXXX"; + char data[ps]; + void *mem; + int fd; + sem_t *s; + pid_t pid; + char *p; + + fd = mkstemp (tmpfname); + if (fd == -1) + { + printf ("cannot open temporary file: %m\n"); + exit (1); + } + + /* Make sure it is always removed. */ + unlink (tmpfname); + + /* Create one page of data. */ + memset (data, '\0', ps); + + /* Write the data to the file. */ + if (write (fd, data, ps) != ps) + { + puts ("short write"); + exit (1); + } + + mem = mmap (NULL, ps, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + if (mem == MAP_FAILED) + { + printf ("mmap failed: %m\n"); + exit (1); + } + + s = (sem_t *) (((uintptr_t) mem + __alignof (sem_t)) + & ~(__alignof (sem_t) - 1)); + p = (char *) (s + 1); + + if (sem_init (s, 1, 1) == -1) + { + puts ("init failed"); + exit (1); + } + + if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1) + { + puts ("1st wait failed"); + exit (1); + } + + errno = 0; + if (TEMP_FAILURE_RETRY (sem_trywait (s)) != -1) + { + puts ("trywait succeeded"); + exit (1); + } + else if (errno != EAGAIN) + { + puts ("trywait didn't return EAGAIN"); + exit (1); + } + + *p = 0; + + puts ("going to fork now"); + pid = fork (); + if (pid == -1) + { + puts ("fork failed"); + exit (1); + } + else if (pid == 0) + { + /* Play some lock ping-pong. It's our turn to unlock first. */ + if ((*p)++ != 0) + { + puts ("child: *p != 0"); + exit (1); + } + + if (sem_post (s) == -1) + { + puts ("child: 1st post failed"); + exit (1); + } + + puts ("child done"); + } + else + { + if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1) + { + printf ("parent: 2nd wait failed: %m\n"); + exit (1); + } + + if (*p != 1) + { + puts ("*p != 1"); + exit (1); + } + + puts ("parent done"); + } + + exit (0); +} |