missing/flock.c

   1 #include "ruby/internal/config.h"
   2 #include "ruby/ruby.h"
   3
   4 #if defined _WIN32
   5 #elif defined __wasi__
   6 #include <errno.h>
   7
   8 int
   9 flock(int fd, int operation)
  10 {
  11     errno = EINVAL;
  12     return -1;
  13 }
  14 #elif defined HAVE_FCNTL && defined HAVE_FCNTL_H
  15
  16 /* These are the flock() constants.  Since this systems doesn't have
  17    flock(), the values of the constants are probably not available.
  18 */
  19 # ifndef LOCK_SH
  20 #  define LOCK_SH 1
  21 # endif
  22 # ifndef LOCK_EX
  23 #  define LOCK_EX 2
  24 # endif
  25 # ifndef LOCK_NB
  26 #  define LOCK_NB 4
  27 # endif
  28 # ifndef LOCK_UN
  29 #  define LOCK_UN 8
  30 # endif
  31
  32 #include <fcntl.h>
  33 #include <unistd.h>
  34 #include <errno.h>
  35
  36 int
  37 flock(int fd, int operation)
  38 {
  39     struct flock lock;
  40
  41     switch (operation & ~LOCK_NB) {
  42     case LOCK_SH:
  43         lock.l_type = F_RDLCK;
  44         break;
  45     case LOCK_EX:
  46         lock.l_type = F_WRLCK;
  47         break;
  48     case LOCK_UN:
  49         lock.l_type = F_UNLCK;
  50         break;
  51     default:
  52         errno = EINVAL;
  53         return -1;
  54     }
  55     lock.l_whence = SEEK_SET;
  56     lock.l_start = lock.l_len = 0L;
  57
  58     return fcntl(fd, (operation & LOCK_NB) ? F_SETLK : F_SETLKW, &lock);
  59 }
  60
  61 #elif defined(HAVE_LOCKF)
  62
  63 #include <unistd.h>
  64 #include <errno.h>
  65
  66 /*  Emulate flock() with lockf() or fcntl().  This is just to increase
  67     portability of scripts.  The calls might not be completely
  68     interchangeable.  What's really needed is a good file
  69     locking module.
  70 */
  71
  72 # ifndef F_ULOCK
  73 #  define F_ULOCK       0       /* Unlock a previously locked region */
  74 # endif
  75 # ifndef F_LOCK
  76 #  define F_LOCK        1       /* Lock a region for exclusive use */
  77 # endif
  78 # ifndef F_TLOCK
  79 #  define F_TLOCK       2       /* Test and lock a region for exclusive use */
  80 # endif
  81 # ifndef F_TEST
  82 #  define F_TEST        3       /* Test a region for other processes locks */
  83 # endif
  84
  85 /* These are the flock() constants.  Since this systems doesn't have
  86    flock(), the values of the constants are probably not available.
  87 */
  88 # ifndef LOCK_SH
  89 #  define LOCK_SH 1
  90 # endif
  91 # ifndef LOCK_EX
  92 #  define LOCK_EX 2
  93 # endif
  94 # ifndef LOCK_NB
  95 #  define LOCK_NB 4
  96 # endif
  97 # ifndef LOCK_UN
  98 #  define LOCK_UN 8
  99 # endif
 100
 101 int
 102 flock(int fd, int operation)
 103 {
 104     switch (operation) {
 105
 106         /* LOCK_SH - get a shared lock */
 107       case LOCK_SH:
 108         rb_notimplement();
 109         return -1;
 110         /* LOCK_EX - get an exclusive lock */
 111       case LOCK_EX:
 112         return lockf (fd, F_LOCK, 0);
 113
 114         /* LOCK_SH|LOCK_NB - get a non-blocking shared lock */
 115       case LOCK_SH|LOCK_NB:
 116         rb_notimplement();
 117         return -1;
 118         /* LOCK_EX|LOCK_NB - get a non-blocking exclusive lock */
 119       case LOCK_EX|LOCK_NB:
 120         return lockf (fd, F_TLOCK, 0);
 121
 122         /* LOCK_UN - unlock */
 123       case LOCK_UN:
 124         return lockf (fd, F_ULOCK, 0);
 125
 126         /* Default - can't decipher operation */
 127       default:
 128         errno = EINVAL;
 129         return -1;
 130     }
 131 }
 132 #else
 133 int
 134 flock(int fd, int operation)
 135 {
 136     rb_notimplement();
 137     return -1;
 138 }
 139 #endif