1/* $NetBSD: lockf.c,v 1.1 1997/12/20 20:23:18 kleink Exp $ */
2
3/*-
4 * Copyright (c) 1997 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Klaus Klein.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the NetBSD
21 * Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 *
38 * $FreeBSD: head/lib/libc/gen/lockf.c 55837 2000-01-12 09:23:48Z jasone $
39 */
40
41#if defined(LIBC_SCCS) && !defined(lint)
42static const char rcsid[]=
43 "$FreeBSD: head/lib/libc/gen/lockf.c 55837 2000-01-12 09:23:48Z jasone $";
44#endif
45
46#include <errno.h>
47#include <fcntl.h>
48#include <unistd.h>
49
50int
51lockf(filedes, function, size)
52 int filedes;
53 int function;
54 off_t size;
55{
56 struct flock fl;
57 int cmd;
58
59 fl.l_start = 0;
60 fl.l_len = size;
61 fl.l_whence = SEEK_CUR;
62
63 switch (function) {
64 case F_ULOCK:
65 cmd = F_SETLK;
66 fl.l_type = F_UNLCK;
67 break;
68 case F_LOCK:
69 cmd = F_SETLKW;
70 fl.l_type = F_WRLCK;
71 break;
72 case F_TLOCK:
73 cmd = F_SETLK;
74 fl.l_type = F_WRLCK;
75 break;
76 case F_TEST:
77 fl.l_type = F_WRLCK;
78 if (_libc_fcntl(filedes, F_GETLK, &fl) == -1)
79 return (-1);
80 if (fl.l_type == F_UNLCK || fl.l_pid == getpid())
81 return (0);
82 errno = EAGAIN;
83 return (-1);
84 /* NOTREACHED */
85 default:
86 errno = EINVAL;
87 return (-1);
88 /* NOTREACHED */
89 }
90
91 return (_libc_fcntl(filedes, cmd, &fl));
92}