usr/src/lib/libc/port/gen/flock.c

   1 /*
   2  * This file and its contents are supplied under the terms of the
   3  * Common Development and Distribution License ("CDDL"), version 1.0.
   4  * You may only use this file in accordance with the terms of version
   5  * 1.0 of the CDDL.
   6  *
   7  * A full copy of the text of the CDDL should have accompanied this
   8  * source.  A copy of the CDDL is also available via the Internet at
   9  * http://www.illumos.org/license/CDDL.
  10  */
  11
  12 /*
  13  * Copyright 2015 Joyent, Inc.
  14  */
  15
  16 #include <sys/feature_tests.h>
  17
  18 #include "lint.h"
  19 #include <sys/types.h>
  20 #include <sys/file.h>
  21 #include <unistd.h>
  22 #include <errno.h>
  23 #include <fcntl.h>
  24
  25 int
  26 flock(int fildes, int operation)
  27 {
  28         struct flock64 l;
  29         int op;
  30         int rv;
  31
  32         l.l_whence = SEEK_SET;
  33         l.l_start = 0;
  34         l.l_len = 0;
  35         l.l_sysid = 0;
  36         l.l_pid = 0;
  37
  38         switch (operation & ~LOCK_NB) {
  39         case LOCK_UN:
  40                 if (operation & LOCK_NB) {
  41                         errno = EINVAL;
  42                         return (-1);
  43                 }
  44                 l.l_type = F_UNLCK;
  45                 rv = fcntl(fildes, F_FLOCK, &l);
  46                 break;
  47         case LOCK_EX:
  48         case LOCK_SH:
  49                 l.l_type = ((operation & ~LOCK_NB) == LOCK_EX) ?
  50                     F_WRLCK : F_RDLCK;
  51                 op = (operation & LOCK_NB) ? F_FLOCK : F_FLOCKW;
  52                 rv = fcntl(fildes, op, &l);
  53                 break;
  54         default:
  55                 errno = EINVAL;
  56                 return (-1);
  57         }
  58
  59         return (rv);
  60 }