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
35int __fcntl(int, int, void *);
36#else /* !VARIANT_CANCELABLE */
37int __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
47int
48lockf(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
97