tests/fcntl_lock_thread.c

   1 /* test whether fcntl locking works between threads on this Linux system */
   2
   3 #include <unistd.h>
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <sys/types.h>
   8
   9 #include <fcntl.h>
  10
  11 #include <sys/fcntl.h>
  12
  13 #include <sys/wait.h>
  14
  15 #include <errno.h>
  16 #include <pthread.h>
  17
  18 #define DATA "conftest.fcntl"
  19
  20 #define SEEK_SET 0
  21
  22 static void *test_thread(void *thread_parm)
  23 {
  24         int *status = thread_parm;
  25         int fd, ret;
  26         struct flock lock;
  27
  28         sleep(2);
  29         fd = open(DATA, O_RDWR);
  30
  31         if (fd == -1) {
  32                 fprintf(stderr,"ERROR: failed to open %s (errno=%d)\n",
  33                         DATA, (int)errno);
  34                 pthread_exit(thread_parm);
  35         }
  36
  37         lock.l_type = F_WRLCK;
  38         lock.l_whence = SEEK_SET;
  39         lock.l_start = 0;
  40         lock.l_len = 4;
  41         lock.l_pid = 0;
  42
  43         /* check if a lock applies */
  44         ret = fcntl(fd,F_SETLK,&lock);
  45         if ((ret != -1)) {
  46                 fprintf(stderr,"ERROR: lock test failed (ret=%d errno=%d)\n", ret, (int)errno);
  47         } else {
  48                 *status = 0;  /* SUCCESS! */
  49         }
  50         pthread_exit(thread_parm);
  51 }
  52
  53 /* lock a byte range in a open file */
  54 int main(int argc, char *argv[])
  55 {
  56         struct flock lock;
  57         int fd, ret, status=1, rc;
  58         pid_t pid;
  59         char *testdir = NULL;
  60         pthread_t thread_id;
  61         pthread_attr_t thread_attr;
  62
  63         testdir = getenv("TESTDIR");
  64         if (testdir) chdir(testdir);
  65
  66         alarm(10);
  67
  68         pthread_attr_init(&thread_attr);
  69         pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
  70         rc = pthread_create(&thread_id, &thread_attr, &test_thread, &status);
  71         pthread_attr_destroy(&thread_attr);
  72         if (rc == 0) {
  73                 fprintf(stderr,"created thread_id=%lu\n",
  74                         (unsigned long int)thread_id);
  75         } else {
  76                 fprintf(stderr,"ERROR: thread create failed, rc=%d\n", rc);
  77         }
  78
  79         unlink(DATA);
  80         fd = open(DATA, O_RDWR|O_CREAT|O_RDWR, 0600);
  81
  82         if (fd == -1) {
  83                 fprintf(stderr,"ERROR: failed to open %s (errno=%d)\n",
  84                         DATA, (int)errno);
  85                 exit(1);
  86         }
  87
  88         lock.l_type = F_WRLCK;
  89         lock.l_whence = SEEK_SET;
  90         lock.l_start = 0;
  91         lock.l_len = 4;
  92         lock.l_pid = getpid();
  93
  94         /* set a 4 byte write lock */
  95         fcntl(fd,F_SETLK,&lock);
  96
  97         sleep(4);  /* allow thread to try getting lock */
  98
  99         unlink(DATA);
 100
 101 #if defined(WIFEXITED) && defined(WEXITSTATUS)
 102     if(WIFEXITED(status)) {
 103         status = WEXITSTATUS(status);
 104     } else {
 105         status = 1;
 106     }
 107 #else /* defined(WIFEXITED) && defined(WEXITSTATUS) */
 108         status = (status == 0) ? 0 : 1;
 109 #endif /* defined(WIFEXITED) && defined(WEXITSTATUS) */
 110
 111         if (status) {
 112                 fprintf(stderr,"ERROR: lock test failed with status=%d\n",
 113                         status);
 114         }
 115
 116         exit(status);
 117 }