source/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 #ifdef HAVE_SYS_WAIT_H
  20 #include <sys/wait.h>
  21 #endif
  22
  23 #include <errno.h>
  24
  25 static int sys_waitpid(pid_t pid,int *status,int options)
  26 {
  27 #ifdef HAVE_WAITPID
  28   return waitpid(pid,status,options);
  29 #else /* USE_WAITPID */
  30   return wait4(pid, status, options, NULL);
  31 #endif /* USE_WAITPID */
  32 }
  33
  34 #define DATA "conftest.fcntl"
  35
  36 #ifndef SEEK_SET
  37 #define SEEK_SET 0
  38 #endif
  39
  40 /* lock a byte range in a open file */
  41 int main(int argc, char *argv[])
  42 {
  43         struct flock lock;
  44         int fd, ret, status=1;
  45         pid_t pid;
  46
  47         if (!(pid=fork())) {
  48                 sleep(2);
  49                 fd = open(DATA, O_RDONLY);
  50
  51                 if (fd == -1) {
  52                         fprintf(stderr,"ERROR: failed to open %s (errno=%d)\n",
  53                                 DATA, (int)errno);
  54                         exit(1);
  55                 }
  56
  57                 lock.l_type = F_WRLCK;
  58                 lock.l_whence = SEEK_SET;
  59                 lock.l_start = 0;
  60                 lock.l_len = 4;
  61                 lock.l_pid = getpid();
  62
  63                 lock.l_type = F_WRLCK;
  64
  65                 /* check if a lock applies */
  66                 ret = fcntl(fd,F_GETLK,&lock);
  67
  68                 if ((ret == -1) ||
  69                     (lock.l_type == F_UNLCK)) {
  70                         fprintf(stderr,"ERROR: lock test failed (ret=%d errno=%d)\n", ret, (int)errno);
  71                         exit(1);
  72                 } else {
  73                         exit(0);
  74                 }
  75         }
  76
  77         fd = open(DATA, O_RDWR|O_CREAT|O_TRUNC, 0600);
  78
  79         if (fd == -1) {
  80                 fprintf(stderr,"ERROR: failed to open %s (errno=%d)\n",
  81                         DATA, (int)errno);
  82                 exit(1);
  83         }
  84
  85         lock.l_type = F_WRLCK;
  86         lock.l_whence = SEEK_SET;
  87         lock.l_start = 0;
  88         lock.l_len = 4;
  89         lock.l_pid = getpid();
  90
  91         /* set a 4 byte write lock */
  92         fcntl(fd,F_SETLK,&lock);
  93
  94         sys_waitpid(pid, &status, 0);
  95
  96         unlink(DATA);
  97
  98 #if defined(WIFEXITED) && defined(WEXITSTATUS)
  99     if(WIFEXITED(status)) {
 100         status = WEXITSTATUS(status);
 101     } else {
 102         status = 1;
 103     }
 104 #else /* defined(WIFEXITED) && defined(WEXITSTATUS) */
 105         status = (status == 0) ? 0 : 1;
 106 #endif /* defined(WIFEXITED) && defined(WEXITSTATUS) */
 107
 108         if (status) {
 109                 fprintf(stderr,"ERROR: lock test failed with status=%d\n",
 110                         status);
 111         }
 112
 113         exit(status);
 114 }