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("$FreeBSD$");
33
34 #include "namespace.h"
35 #include <errno.h>
36 #include <fcntl.h>
37 #include <unistd.h>
38 #include "un-namespace.h"
39 #include "libc_private.h"
40
41 int
lockf(int filedes,int function,off_t size)42 lockf(int filedes, int function, off_t size)
43 {
44 struct flock fl;
45 int cmd;
46
47 fl.l_start = 0;
48 fl.l_len = size;
49 fl.l_whence = SEEK_CUR;
50
51 switch (function) {
52 case F_ULOCK:
53 cmd = F_SETLK;
54 fl.l_type = F_UNLCK;
55 break;
56 case F_LOCK:
57 cmd = F_SETLKW;
58 fl.l_type = F_WRLCK;
59 break;
60 case F_TLOCK:
61 cmd = F_SETLK;
62 fl.l_type = F_WRLCK;
63 break;
64 case F_TEST:
65 fl.l_type = F_WRLCK;
66 if (((int (*)(int, int, ...))
67 __libc_interposing[INTERPOS_fcntl])(filedes, F_GETLK, &fl)
68 == -1)
69 return (-1);
70 if (fl.l_type == F_UNLCK || (fl.l_sysid == 0 &&
71 fl.l_pid == getpid()))
72 return (0);
73 errno = EAGAIN;
74 return (-1);
75 /* NOTREACHED */
76 default:
77 errno = EINVAL;
78 return (-1);
79 /* NOTREACHED */
80 }
81
82 return (((int (*)(int, int, ...))
83 __libc_interposing[INTERPOS_fcntl])(filedes, cmd, &fl));
84 }
85