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 #ifdef VARIANT_CANCELABLE
  35 int __fcntl(int, int, void *);
  36 #else /* !VARIANT_CANCELABLE */
  37 int __fcntl_nocancel(int, int, void *);
  38 #endif /* VARIANT_CANCELABLE */
  39
  40
  41 #include "namespace.h"
  42 #include <errno.h>
  43 #include <fcntl.h>
  44 #include <unistd.h>
  45 #include "un-namespace.h"
  46
  47 int
  48 lockf(int filedes, int function, off_t size)
  49 {
  50         struct flock fl;
  51         int cmd;
  52
  53         fl.l_start = 0;
  54         fl.l_len = size;
  55         fl.l_whence = SEEK_CUR;
  56
  57         switch (function) {
  58         case F_ULOCK:
  59                 cmd = F_SETLK;
  60                 fl.l_type = F_UNLCK;
  61                 break;
  62         case F_LOCK:
  63                 cmd = F_SETLKW;
  64                 fl.l_type = F_WRLCK;
  65                 break;
  66         case F_TLOCK:
  67                 cmd = F_SETLK;
  68                 fl.l_type = F_WRLCK;
  69                 break;
  70         case F_TEST:
  71                 fl.l_type = F_WRLCK;
  72 #ifdef VARIANT_CANCELABLE
  73                 if (__fcntl(filedes, F_GETLK, &fl) == -1)
  74                         return (-1);
  75 #else /* !VARIANT_CANCELABLE */
  76                 if (__fcntl_nocancel(filedes, F_GETLK, &fl) == -1)
  77                         return (-1);
  78 #endif /* VARIANT_CANCELABLE */
  79                 if (fl.l_type == F_UNLCK || fl.l_pid == getpid())
  80                         return (0);
  81                 errno = EAGAIN;
  82                 return (-1);
  83                 /* NOTREACHED */
  84         default:
  85                 errno = EINVAL;
  86                 return (-1);
  87                 /* NOTREACHED */
  88         }
  89
  90 #ifdef VARIANT_CANCELABLE
  91         return (__fcntl(filedes, cmd, &fl));
  92 #else /* !VARIANT_CANCELABLE */
  93         return (__fcntl_nocancel(filedes, cmd, &fl));
  94 #endif /* VARIANT_CANCELABLE */
  95 }
  96