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/* Copyright (C) 2002-2021 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
<https://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>
static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t lock2 = PTHREAD_MUTEX_INITIALIZER;
static int fd;
static void *
tf (void *arg)
{
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)
{
char tmp[] = "/tmp/tst-flock2-XXXXXX";
fd = mkstemp (tmp);
if (fd == -1)
{
puts ("mkstemp failed");
return 1;
}
unlink (tmp);
int i;
for (i = 0; i < 20; ++i)
write (fd, "foobar xyzzy", 12);
pthread_barrier_t *b;
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;
}
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)
{
/* 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 (&lock) != 0)
{
puts ("1st locking of lock failed");
return 1;
}
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;
}
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;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"
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