1/*	$NetBSD: lockf.c,v 1.3 2008/04/28 20:22:59 martin Exp $	*/
2/*-
3 * SPDX-License-Identifier: BSD-2-Clause-NetBSD
4 *
5 * Copyright (c) 1997 The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Klaus Klein.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD$");
35
36#include "namespace.h"
37#include <errno.h>
38#include <fcntl.h>
39#include <unistd.h>
40#include "un-namespace.h"
41#include "libc_private.h"
42
43int
44lockf(int filedes, int function, off_t size)
45{
46	struct flock fl;
47	int cmd;
48
49	fl.l_start = 0;
50	fl.l_len = size;
51	fl.l_whence = SEEK_CUR;
52
53	switch (function) {
54	case F_ULOCK:
55		cmd = F_SETLK;
56		fl.l_type = F_UNLCK;
57		break;
58	case F_LOCK:
59		cmd = F_SETLKW;
60		fl.l_type = F_WRLCK;
61		break;
62	case F_TLOCK:
63		cmd = F_SETLK;
64		fl.l_type = F_WRLCK;
65		break;
66	case F_TEST:
67		fl.l_type = F_WRLCK;
68		if (((int (*)(int, int, ...))
69		    __libc_interposing[INTERPOS_fcntl])(filedes, F_GETLK, &fl)
70		    == -1)
71			return (-1);
72		if (fl.l_type == F_UNLCK || (fl.l_sysid == 0 &&
73		    fl.l_pid == getpid()))
74			return (0);
75		errno = EAGAIN;
76		return (-1);
77		/* NOTREACHED */
78	default:
79		errno = EINVAL;
80		return (-1);
81		/* NOTREACHED */
82	}
83
84	return (((int (*)(int, int, ...))
85	    __libc_interposing[INTERPOS_fcntl])(filedes, cmd, &fl));
86}
87