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
43 int
lockf(int filedes,int function,off_t size)44 lockf(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