xref: /freebsd/lib/libc/sys/lockf.c (revision d7847a8d351436a4654bd2c746bc9c04401160ee)
1*d7847a8dSBrooks Davis /*	$NetBSD: lockf.c,v 1.3 2008/04/28 20:22:59 martin Exp $	*/
2*d7847a8dSBrooks Davis /*-
3*d7847a8dSBrooks Davis  * SPDX-License-Identifier: BSD-2-Clause
4*d7847a8dSBrooks Davis  *
5*d7847a8dSBrooks Davis  * Copyright (c) 1997 The NetBSD Foundation, Inc.
6*d7847a8dSBrooks Davis  * All rights reserved.
7*d7847a8dSBrooks Davis  *
8*d7847a8dSBrooks Davis  * This code is derived from software contributed to The NetBSD Foundation
9*d7847a8dSBrooks Davis  * by Klaus Klein.
10*d7847a8dSBrooks Davis  *
11*d7847a8dSBrooks Davis  * Redistribution and use in source and binary forms, with or without
12*d7847a8dSBrooks Davis  * modification, are permitted provided that the following conditions
13*d7847a8dSBrooks Davis  * are met:
14*d7847a8dSBrooks Davis  * 1. Redistributions of source code must retain the above copyright
15*d7847a8dSBrooks Davis  *    notice, this list of conditions and the following disclaimer.
16*d7847a8dSBrooks Davis  * 2. Redistributions in binary form must reproduce the above copyright
17*d7847a8dSBrooks Davis  *    notice, this list of conditions and the following disclaimer in the
18*d7847a8dSBrooks Davis  *    documentation and/or other materials provided with the distribution.
19*d7847a8dSBrooks Davis  *
20*d7847a8dSBrooks Davis  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21*d7847a8dSBrooks Davis  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22*d7847a8dSBrooks Davis  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23*d7847a8dSBrooks Davis  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24*d7847a8dSBrooks Davis  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25*d7847a8dSBrooks Davis  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26*d7847a8dSBrooks Davis  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27*d7847a8dSBrooks Davis  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28*d7847a8dSBrooks Davis  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29*d7847a8dSBrooks Davis  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30*d7847a8dSBrooks Davis  * POSSIBILITY OF SUCH DAMAGE.
31*d7847a8dSBrooks Davis  */
32*d7847a8dSBrooks Davis 
33*d7847a8dSBrooks Davis #include "namespace.h"
34*d7847a8dSBrooks Davis #include <errno.h>
35*d7847a8dSBrooks Davis #include <fcntl.h>
36*d7847a8dSBrooks Davis #include <unistd.h>
37*d7847a8dSBrooks Davis #include "un-namespace.h"
38*d7847a8dSBrooks Davis #include "libc_private.h"
39*d7847a8dSBrooks Davis 
40*d7847a8dSBrooks Davis int
41*d7847a8dSBrooks Davis lockf(int filedes, int function, off_t size)
42*d7847a8dSBrooks Davis {
43*d7847a8dSBrooks Davis 	struct flock fl;
44*d7847a8dSBrooks Davis 	int cmd;
45*d7847a8dSBrooks Davis 
46*d7847a8dSBrooks Davis 	fl.l_start = 0;
47*d7847a8dSBrooks Davis 	fl.l_len = size;
48*d7847a8dSBrooks Davis 	fl.l_whence = SEEK_CUR;
49*d7847a8dSBrooks Davis 
50*d7847a8dSBrooks Davis 	switch (function) {
51*d7847a8dSBrooks Davis 	case F_ULOCK:
52*d7847a8dSBrooks Davis 		cmd = F_SETLK;
53*d7847a8dSBrooks Davis 		fl.l_type = F_UNLCK;
54*d7847a8dSBrooks Davis 		break;
55*d7847a8dSBrooks Davis 	case F_LOCK:
56*d7847a8dSBrooks Davis 		cmd = F_SETLKW;
57*d7847a8dSBrooks Davis 		fl.l_type = F_WRLCK;
58*d7847a8dSBrooks Davis 		break;
59*d7847a8dSBrooks Davis 	case F_TLOCK:
60*d7847a8dSBrooks Davis 		cmd = F_SETLK;
61*d7847a8dSBrooks Davis 		fl.l_type = F_WRLCK;
62*d7847a8dSBrooks Davis 		break;
63*d7847a8dSBrooks Davis 	case F_TEST:
64*d7847a8dSBrooks Davis 		fl.l_type = F_WRLCK;
65*d7847a8dSBrooks Davis 		if (((int (*)(int, int, ...))
66*d7847a8dSBrooks Davis 		    *(__libc_interposing_slot(INTERPOS_fcntl)))
67*d7847a8dSBrooks Davis 		    (filedes, F_GETLK, &fl) == -1)
68*d7847a8dSBrooks Davis 			return (-1);
69*d7847a8dSBrooks Davis 		if (fl.l_type == F_UNLCK || (fl.l_sysid == 0 &&
70*d7847a8dSBrooks Davis 		    fl.l_pid == getpid()))
71*d7847a8dSBrooks Davis 			return (0);
72*d7847a8dSBrooks Davis 		errno = EAGAIN;
73*d7847a8dSBrooks Davis 		return (-1);
74*d7847a8dSBrooks Davis 		/* NOTREACHED */
75*d7847a8dSBrooks Davis 	default:
76*d7847a8dSBrooks Davis 		errno = EINVAL;
77*d7847a8dSBrooks Davis 		return (-1);
78*d7847a8dSBrooks Davis 		/* NOTREACHED */
79*d7847a8dSBrooks Davis 	}
80*d7847a8dSBrooks Davis 
81*d7847a8dSBrooks Davis 	return (((int (*)(int, int, ...))
82*d7847a8dSBrooks Davis 	    *(__libc_interposing_slot(INTERPOS_fcntl)))(filedes, cmd, &fl));
83*d7847a8dSBrooks Davis }
84