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: src/lib/libc/gen/lockf.c,v 1.5 2000/01/27 23:06:17 jasone Exp $
39 * $DragonFly: src/lib/libc/gen/lockf.c,v 1.4 2005/11/13 00:07:42 swildner Exp $
40 */
41
42 #include "namespace.h"
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <unistd.h>
46 #include "un-namespace.h"
47
48 int
lockf(int filedes,int function,off_t size)49 lockf(int filedes, int function, off_t size)
50 {
51 struct flock fl;
52 int cmd;
53
54 fl.l_start = 0;
55 fl.l_len = size;
56 fl.l_whence = SEEK_CUR;
57
58 switch (function) {
59 case F_ULOCK:
60 cmd = F_SETLK;
61 fl.l_type = F_UNLCK;
62 break;
63 case F_LOCK:
64 cmd = F_SETLKW;
65 fl.l_type = F_WRLCK;
66 break;
67 case F_TLOCK:
68 cmd = F_SETLK;
69 fl.l_type = F_WRLCK;
70 break;
71 case F_TEST:
72 fl.l_type = F_WRLCK;
73 if (_fcntl(filedes, F_GETLK, &fl) == -1)
74 return (-1);
75 if (fl.l_type == F_UNLCK || fl.l_pid == getpid())
76 return (0);
77 errno = EAGAIN;
78 return (-1);
79 /* NOTREACHED */
80 default:
81 errno = EINVAL;
82 return (-1);
83 /* NOTREACHED */
84 }
85
86 return (_fcntl(filedes, cmd, &fl));
87 }
88