gen/FreeBSD/lockf.c

   1 /*      $NetBSD: lockf.c,v 1.3 2008/04/28 20:22:59 martin Exp $ */
   2 /*-
   3  * Copyright (c) 1997 The NetBSD Foundation, Inc.
   4  * All rights reserved.
   5  *
   6  * This code is derived from software contributed to The NetBSD Foundation
   7  * by Klaus Klein.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  20  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  21  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  22  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28  * POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include <sys/cdefs.h>
  32 __FBSDID("$FreeBSD: src/lib/libc/gen/lockf.c,v 1.10 2009/03/04 01:01:26 delphij Exp $");
  33
  34 #include "namespace.h"
  35 #include <errno.h>
  36 #include <fcntl.h>
  37 #include <unistd.h>
  38 #include "un-namespace.h"
  39
  40 int
  41 lockf(int filedes, int function, off_t size)
  42 {
  43         struct flock fl;
  44         int cmd;
  45
  46         fl.l_start = 0;
  47         fl.l_len = size;
  48         fl.l_whence = SEEK_CUR;
  49
  50         switch (function) {
  51         case F_ULOCK:
  52                 cmd = F_SETLK;
  53                 fl.l_type = F_UNLCK;
  54                 break;
  55         case F_LOCK:
  56                 cmd = F_SETLKW;
  57                 fl.l_type = F_WRLCK;
  58                 break;
  59         case F_TLOCK:
  60                 cmd = F_SETLK;
  61                 fl.l_type = F_WRLCK;
  62                 break;
  63         case F_TEST:
  64                 fl.l_type = F_WRLCK;
  65                 if (_fcntl(filedes, F_GETLK, &fl) == -1)
  66                         return (-1);
  67                 if (fl.l_type == F_UNLCK || (fl.l_sysid == 0 && fl.l_pid == getpid()))
  68                         return (0);
  69                 errno = EAGAIN;
  70                 return (-1);
  71                 /* NOTREACHED */
  72         default:
  73                 errno = EINVAL;
  74                 return (-1);
  75                 /* NOTREACHED */
  76         }
  77
  78         return (_fcntl(filedes, cmd, &fl));
  79 }