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("$FreeBSD$");
33
34#include "namespace.h"
35#include <errno.h>
36#include <fcntl.h>
37#include <unistd.h>
38#include "un-namespace.h"
39
40int
41lockf(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}
80