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 static int sys_waitpid(pid_t pid,int *status,int options)
  19 {
  20   return waitpid(pid,status,options);
  21 }
  22
  23 #define DATA "conftest.fcntl"
  24
  25 #define SEEK_SET 0
  26
  27 static void *test_thread(void *thread_parm)
  28 {
  29         int *status = thread_parm;
  30         int fd, ret;
  31         struct flock lock;
  32
  33         sleep(2);
  34         fd = open(DATA, O_RDWR);
  35
  36         if (fd == -1) {
  37                 fprintf(stderr,"ERROR: failed to open %s (errno=%d)\n",
  38                         DATA, (int)errno);
  39                 pthread_exit(thread_parm);
  40         }
  41
  42         lock.l_type = F_WRLCK;
  43         lock.l_whence = SEEK_SET;
  44         lock.l_start = 0;
  45         lock.l_len = 4;
  46         lock.l_pid = 0;
  47
  48         /* check if a lock applies */
  49         ret = fcntl(fd,F_SETLK,&lock);
  50         if ((ret != -1)) {
  51                 fprintf(stderr,"ERROR: lock test failed (ret=%d errno=%d)\n", ret, (int)errno);
  52         } else {
  53                 *status = 0;  /* SUCCESS! */
  54         }
  55         pthread_exit(thread_parm);
  56 }
  57
  58 /* lock a byte range in a open file */
  59 int main(int argc, char *argv[])
  60 {
  61         struct flock lock;
  62         int fd, ret, status=1, rc;
  63         pid_t pid;
  64         char *testdir = NULL;
  65         pthread_t thread_id;
  66         pthread_attr_t thread_attr;
  67
  68         testdir = getenv("TESTDIR");
  69         if (testdir) chdir(testdir);
  70
  71         alarm(10);
  72
  73         pthread_attr_init(&thread_attr);
  74         pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
  75         rc = pthread_create(&thread_id, &thread_attr, &test_thread, &status);
  76         pthread_attr_destroy(&thread_attr);
  77         if (rc == 0) {
  78                 fprintf(stderr,"created thread_id=%lu\n",
  79                         (unsigned long int)thread_id);
  80         } else {
  81                 fprintf(stderr,"ERROR: thread create failed, rc=%d\n", rc);
  82         }
  83
  84         unlink(DATA);
  85         fd = open(DATA, O_RDWR|O_CREAT|O_RDWR, 0600);
  86
  87         if (fd == -1) {
  88                 fprintf(stderr,"ERROR: failed to open %s (errno=%d)\n",
  89                         DATA, (int)errno);
  90                 exit(1);
  91         }
  92
  93         lock.l_type = F_WRLCK;
  94         lock.l_whence = SEEK_SET;
  95         lock.l_start = 0;
  96         lock.l_len = 4;
  97         lock.l_pid = getpid();
  98
  99         /* set a 4 byte write lock */
 100         fcntl(fd,F_SETLK,&lock);
 101
 102         sleep(4);  /* allow thread to try getting lock */
 103
 104         unlink(DATA);
 105
 106 #if defined(WIFEXITED) && defined(WEXITSTATUS)
 107     if(WIFEXITED(status)) {
 108         status = WEXITSTATUS(status);
 109     } else {
 110         status = 1;
 111     }
 112 #else /* defined(WIFEXITED) && defined(WEXITSTATUS) */
 113         status = (status == 0) ? 0 : 1;
 114 #endif /* defined(WIFEXITED) && defined(WEXITSTATUS) */
 115
 116         if (status) {
 117                 fprintf(stderr,"ERROR: lock test failed with status=%d\n",
 118                         status);
 119         }
 120
 121         exit(status);
 122 }