source3/tests/fcntl_lock.c

   1 /* test whether fcntl locking works on this system */
   2
   3 #if defined(HAVE_UNISTD_H)
   4 #include <unistd.h>
   5 #endif
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <sys/types.h>
  10
  11 #ifdef HAVE_FCNTL_H
  12 #include <fcntl.h>
  13 #endif
  14
  15 #ifdef HAVE_SYS_FCNTL_H
  16 #include <sys/fcntl.h>
  17 #endif
  18
  19 #include <errno.h>
  20
  21 static int sys_waitpid(pid_t pid,int *status,int options)
  22 {
  23 #ifdef HAVE_WAITPID
  24   return waitpid(pid,status,options);
  25 #else /* USE_WAITPID */
  26   return wait4(pid, status, options, NULL);
  27 #endif /* USE_WAITPID */
  28 }
  29
  30 #define DATA "conftest.fcntl"
  31
  32 #ifndef SEEK_SET
  33 #define SEEK_SET 0
  34 #endif
  35
  36 /* lock a byte range in a open file */
  37 int main(int argc, char *argv[])
  38 {
  39         struct flock lock;
  40         int fd, ret, status=1;
  41         pid_t pid;
  42
  43         if (!(pid=fork())) {
  44                 sleep(2);
  45                 fd = open(DATA, O_RDONLY);
  46
  47                 if (fd == -1) exit(1);
  48
  49                 lock.l_type = F_WRLCK;
  50                 lock.l_whence = SEEK_SET;
  51                 lock.l_start = 0;
  52                 lock.l_len = 4;
  53                 lock.l_pid = getpid();
  54
  55                 lock.l_type = F_WRLCK;
  56
  57                 /* check if a lock applies */
  58                 ret = fcntl(fd,F_GETLK,&lock);
  59
  60                 if ((ret == -1) ||
  61                     (lock.l_type == F_UNLCK)) {
  62                         exit(1);
  63                 } else {
  64                         exit(0);
  65                 }
  66         }
  67
  68         fd = open(DATA, O_RDWR|O_CREAT|O_TRUNC, 0600);
  69
  70         lock.l_type = F_WRLCK;
  71         lock.l_whence = SEEK_SET;
  72         lock.l_start = 0;
  73         lock.l_len = 4;
  74         lock.l_pid = getpid();
  75
  76         /* set a 4 byte write lock */
  77         fcntl(fd,F_SETLK,&lock);
  78
  79         sys_waitpid(pid, &status, 0);
  80
  81         unlink(DATA);
  82
  83 #if defined(WIFEXITED) && defined(WEXITSTATUS)
  84     if(WIFEXITED(status)) {
  85         status = WEXITSTATUS(status);
  86     } else {
  87         status = 1;
  88     }
  89 #else /* defined(WIFEXITED) && defined(WEXITSTATUS) */
  90         status = (status == 0) ? 0 : 1;
  91 #endif /* defined(WIFEXITED) && defined(WEXITSTATUS) */
  92
  93         exit(status);
  94 }