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tst-flock2.c
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tst-flock2.c
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/* Copyright (C) 2002-2016 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, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/file.h>
#include <sys/mman.h>
#include <sys/wait.h>
#ifdef __EMX__
#define INCL_BASE
#include <os2.h>
static int do_test(void);
#define TEST_FUNCTION do_test()
#include "../test-skeleton.c"
typedef struct pthread_barrier_t
{
HMTX hmtx;
HEV hev;
size_t cnt;
size_t cnt_max;
} pthread_barrier_t;
static void pthread_barrier_wait (pthread_barrier_t *b)
{
APIRET arc;
int wait = 1;
arc = DosRequestMutexSem (b->hmtx, SEM_INDEFINITE_WAIT);
if (arc)
{
puts ("DosRequestMutexSem failed");
exit (1);
}
if (++b->cnt == b->cnt_max)
{
b->cnt = 0;
wait = 0;
arc = DosPostEventSem (b->hev);
if (arc)
{
puts ("DosPostEventSem failed");
exit (1);
}
}
arc = DosReleaseMutexSem (b->hmtx);
if (arc)
{
puts ("DosReleaseMutexSem failed");
exit (1);
}
if (wait)
{
arc = DosWaitEventSem (b->hev, SEM_INDEFINITE_WAIT);
if (arc)
{
puts ("DosWaitEventSem failed");
exit (1);
}
}
}
#endif
static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t lock2 = PTHREAD_MUTEX_INITIALIZER;
static int fd;
static void *
tf (void *arg)
{
if (pthread_mutex_lock (&lock))
{
puts ("1st locking of lock failed");
exit (1);
}
struct flock fl =
{
.l_type = F_WRLCK,
.l_start = 0,
.l_whence = SEEK_SET,
.l_len = 10
};
if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)
{
puts ("fourth fcntl failed");
exit (1);
}
pthread_mutex_unlock (&lock);
pthread_mutex_lock (&lock2);
return NULL;
}
static int
do_test (void)
{
fd = create_temp_file("tst-flock2-", NULL);
if (fd == -1)
{
puts ("create_temp_file failed");
return 1;
}
int i;
for (i = 0; i < 20; ++i)
write (fd, "foobar xyzzy", 12);
pthread_barrier_t *b;
#ifdef __EMX__
APIRET arc;
arc = DosAllocSharedMem ((PPVOID) &b, NULL, sizeof (pthread_barrier_t),
PAG_READ | PAG_WRITE | PAG_COMMIT | OBJ_GETTABLE);
if (arc)
{
puts ("DosAllocSharedMem failed");
return 1;
}
b->hmtx = NULLHANDLE;
arc = DosCreateMutexSem (NULL, &b->hmtx, DC_SEM_SHARED, FALSE);
if (arc)
{
puts ("DosCreateMutexSem failed");
return 1;
}
b->hev = NULLHANDLE;
arc = DosCreateEventSem (NULL, &b->hev, DC_SEM_SHARED | DCE_AUTORESET, FALSE);
if (arc)
{
puts ("DosCreateEventSem failed");
return 1;
}
b->cnt = 0;
b->cnt_max = 2;
#else
b = mmap (NULL, sizeof (pthread_barrier_t), PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0);
if (b == MAP_FAILED)
{
puts ("mmap failed");
return 1;
}
pthread_barrierattr_t ba;
if (pthread_barrierattr_init (&ba) != 0)
{
puts ("barrierattr_init failed");
return 1;
}
if (pthread_barrierattr_setpshared (&ba, PTHREAD_PROCESS_SHARED) != 0)
{
puts ("barrierattr_setpshared failed");
return 1;
}
if (pthread_barrier_init (b, &ba, 2) != 0)
{
puts ("barrier_init failed");
return 1;
}
if (pthread_barrierattr_destroy (&ba) != 0)
{
puts ("barrierattr_destroy failed");
return 1;
}
#endif
struct flock fl =
{
.l_type = F_WRLCK,
.l_start = 0,
.l_whence = SEEK_SET,
.l_len = 10
};
if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)
{
puts ("first fcntl failed");
return 1;
}
pid_t pid = fork ();
if (pid == -1)
{
puts ("fork failed");
return 1;
}
if (pid == 0)
{
#ifdef __EMX__
arc = DosGetSharedMem (b, PAG_READ | PAG_WRITE);
if (arc)
{
puts ("DosGetSharedMem failed");
return 1;
}
arc = DosOpenMutexSem (NULL, &b->hmtx);
if (arc)
{
puts ("DosOpenMutexSem failed");
return 1;
}
arc = DosOpenEventSem (NULL, &b->hev);
if (arc)
{
puts ("DosOpenEventSem failed");
return 1;
}
#endif
/* Make sure the child does not stay around indefinitely. */
alarm (10);
/* Try to get the lock. */
if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0)
{
puts ("child: second flock succeeded");
return 1;
}
}
pthread_barrier_wait (b);
if (pid != 0)
{
fl.l_type = F_UNLCK;
if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)
{
puts ("third fcntl failed");
return 1;
}
}
pthread_barrier_wait (b);
pthread_t th;
if (pid == 0)
{
if (pthread_mutex_lock (&lock2) != 0)
{
puts ("1st locking of lock2 failed");
return 1;
}
if (pthread_create (&th, NULL, tf, NULL) != 0)
{
puts ("pthread_create failed");
return 1;
}
/* Let the new thread run. */
sleep (1);
if (pthread_mutex_lock (&lock) != 0)
{
puts ("2nd locking of lock failed");
return 1;
}
puts ("child locked file");
}
pthread_barrier_wait (b);
if (pid != 0)
{
fl.l_type = F_WRLCK;
if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0)
{
puts ("fifth fcntl succeeded");
return 1;
}
puts ("file locked by child");
}
pthread_barrier_wait (b);
if (pid == 0)
{
if (pthread_mutex_unlock (&lock2) != 0)
{
puts ("unlock of lock2 failed");
return 1;
}
if (pthread_join (th, NULL) != 0)
{
puts ("join failed");
return 1;
}
puts ("child's thread terminated");
}
pthread_barrier_wait (b);
if (pid != 0)
{
fl.l_type = F_WRLCK;
if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0)
{
puts ("fifth fcntl succeeded");
return 1;
}
puts ("file still locked");
}
pthread_barrier_wait (b);
if (pid == 0)
{
_exit (0);
}
int status;
if (TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)) != pid)
{
puts ("waitpid failed");
return 1;
}
puts ("child terminated");
if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)
{
puts ("sixth fcntl failed");
return 1;
}
return status;
}