missing/flock.c

   1 #include "ruby/config.h"
   2
   3 #if defined _WIN32
   4 #elif defined HAVE_FCNTL && defined HAVE_FCNTL_H
   5
   6 /* These are the flock() constants.  Since this sytems doesn't have
   7    flock(), the values of the constants are probably not available.
   8 */
   9 # ifndef LOCK_SH
  10 #  define LOCK_SH 1
  11 # endif
  12 # ifndef LOCK_EX
  13 #  define LOCK_EX 2
  14 # endif
  15 # ifndef LOCK_NB
  16 #  define LOCK_NB 4
  17 # endif
  18 # ifndef LOCK_UN
  19 #  define LOCK_UN 8
  20 # endif
  21
  22 #include <fcntl.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25
  26 int
  27 flock(int fd, int operation)
  28 {
  29     struct flock lock;
  30
  31     switch (operation & ~LOCK_NB) {
  32     case LOCK_SH:
  33         lock.l_type = F_RDLCK;
  34         break;
  35     case LOCK_EX:
  36         lock.l_type = F_WRLCK;
  37         break;
  38     case LOCK_UN:
  39         lock.l_type = F_UNLCK;
  40         break;
  41     default:
  42         errno = EINVAL;
  43         return -1;
  44     }
  45     lock.l_whence = SEEK_SET;
  46     lock.l_start = lock.l_len = 0L;
  47
  48     return fcntl(fd, (operation & LOCK_NB) ? F_SETLK : F_SETLKW, &lock);
  49 }
  50
  51 #elif defined(HAVE_LOCKF)
  52
  53 #include <unistd.h>
  54 #include <errno.h>
  55
  56 /*  Emulate flock() with lockf() or fcntl().  This is just to increase
  57     portability of scripts.  The calls might not be completely
  58     interchangeable.  What's really needed is a good file
  59     locking module.
  60 */
  61
  62 # ifndef F_ULOCK
  63 #  define F_ULOCK       0       /* Unlock a previously locked region */
  64 # endif
  65 # ifndef F_LOCK
  66 #  define F_LOCK        1       /* Lock a region for exclusive use */
  67 # endif
  68 # ifndef F_TLOCK
  69 #  define F_TLOCK       2       /* Test and lock a region for exclusive use */
  70 # endif
  71 # ifndef F_TEST
  72 #  define F_TEST        3       /* Test a region for other processes locks */
  73 # endif
  74
  75 /* These are the flock() constants.  Since this sytems doesn't have
  76    flock(), the values of the constants are probably not available.
  77 */
  78 # ifndef LOCK_SH
  79 #  define LOCK_SH 1
  80 # endif
  81 # ifndef LOCK_EX
  82 #  define LOCK_EX 2
  83 # endif
  84 # ifndef LOCK_NB
  85 #  define LOCK_NB 4
  86 # endif
  87 # ifndef LOCK_UN
  88 #  define LOCK_UN 8
  89 # endif
  90
  91 int
  92 flock(int fd, int operation)
  93 {
  94     switch (operation) {
  95
  96         /* LOCK_SH - get a shared lock */
  97       case LOCK_SH:
  98         rb_notimplement();
  99         return -1;
 100         /* LOCK_EX - get an exclusive lock */
 101       case LOCK_EX:
 102         return lockf (fd, F_LOCK, 0);
 103
 104         /* LOCK_SH|LOCK_NB - get a non-blocking shared lock */
 105       case LOCK_SH|LOCK_NB:
 106         rb_notimplement();
 107         return -1;
 108         /* LOCK_EX|LOCK_NB - get a non-blocking exclusive lock */
 109       case LOCK_EX|LOCK_NB:
 110         return lockf (fd, F_TLOCK, 0);
 111
 112         /* LOCK_UN - unlock */
 113       case LOCK_UN:
 114         return lockf (fd, F_ULOCK, 0);
 115
 116         /* Default - can't decipher operation */
 117       default:
 118         errno = EINVAL;
 119         return -1;
 120     }
 121 }
 122 #else
 123 int
 124 flock(int fd, int operation)
 125 {
 126     rb_notimplement();
 127     return -1;
 128 }
 129 #endif