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/* test whether fcntl locking works between threads on this Linux system */
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <fcntl.h>
#include <sys/fcntl.h>
#include <sys/wait.h>
#include <errno.h>
#include <pthread.h>
#define DATA "conftest.fcntl"
#define SEEK_SET 0
static void *test_thread(void *thread_parm)
{
int *status = thread_parm;
int fd, ret;
struct flock lock;
sleep(2);
fd = open(DATA, O_RDWR);
if (fd == -1) {
fprintf(stderr,"ERROR: failed to open %s (errno=%d)\n",
DATA, (int)errno);
pthread_exit(thread_parm);
}
lock.l_type = F_WRLCK;
lock.l_whence = SEEK_SET;
lock.l_start = 0;
lock.l_len = 4;
lock.l_pid = 0;
/* check if a lock applies */
ret = fcntl(fd,F_SETLK,&lock);
if ((ret != -1)) {
fprintf(stderr,"ERROR: lock test failed (ret=%d errno=%d)\n", ret, (int)errno);
} else {
*status = 0; /* SUCCESS! */
}
pthread_exit(thread_parm);
}
/* lock a byte range in a open file */
int main(int argc, char *argv[])
{
struct flock lock;
int fd, ret, status=1, rc;
pid_t pid;
char *testdir = NULL;
pthread_t thread_id;
pthread_attr_t thread_attr;
testdir = getenv("TESTDIR");
if (testdir) chdir(testdir);
alarm(10);
pthread_attr_init(&thread_attr);
pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
rc = pthread_create(&thread_id, &thread_attr, &test_thread, &status);
pthread_attr_destroy(&thread_attr);
if (rc == 0) {
fprintf(stderr,"created thread_id=%lu\n",
(unsigned long int)thread_id);
} else {
fprintf(stderr,"ERROR: thread create failed, rc=%d\n", rc);
}
unlink(DATA);
fd = open(DATA, O_RDWR|O_CREAT|O_RDWR, 0600);
if (fd == -1) {
fprintf(stderr,"ERROR: failed to open %s (errno=%d)\n",
DATA, (int)errno);
exit(1);
}
lock.l_type = F_WRLCK;
lock.l_whence = SEEK_SET;
lock.l_start = 0;
lock.l_len = 4;
lock.l_pid = getpid();
/* set a 4 byte write lock */
fcntl(fd,F_SETLK,&lock);
sleep(4); /* allow thread to try getting lock */
unlink(DATA);
#if defined(WIFEXITED) && defined(WEXITSTATUS)
if(WIFEXITED(status)) {
status = WEXITSTATUS(status);
} else {
status = 1;
}
#else /* defined(WIFEXITED) && defined(WEXITSTATUS) */
status = (status == 0) ? 0 : 1;
#endif /* defined(WIFEXITED) && defined(WEXITSTATUS) */
if (status) {
fprintf(stderr,"ERROR: lock test failed with status=%d\n",
status);
}
exit(status);
}
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