1 |
|
|
/* $OpenBSD: lockf.c,v 1.5 2008/06/26 05:42:05 ray Exp $ */ |
2 |
|
|
/* $NetBSD: lockf.c,v 1.1 1997/12/20 20:23:18 kleink Exp $ */ |
3 |
|
|
|
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 <errno.h> |
34 |
|
|
#include <fcntl.h> |
35 |
|
|
#include <unistd.h> |
36 |
|
|
|
37 |
|
|
int |
38 |
|
|
lockf(int filedes, int function, off_t size) |
39 |
|
|
{ |
40 |
|
|
struct flock fl; |
41 |
|
|
int cmd; |
42 |
|
|
|
43 |
|
|
fl.l_start = 0; |
44 |
|
|
fl.l_len = size; |
45 |
|
|
fl.l_whence = SEEK_CUR; |
46 |
|
|
|
47 |
|
|
switch (function) { |
48 |
|
|
case F_ULOCK: |
49 |
|
|
cmd = F_SETLK; |
50 |
|
|
fl.l_type = F_UNLCK; |
51 |
|
|
break; |
52 |
|
|
case F_LOCK: |
53 |
|
|
cmd = F_SETLKW; |
54 |
|
|
fl.l_type = F_WRLCK; |
55 |
|
|
break; |
56 |
|
|
case F_TLOCK: |
57 |
|
|
cmd = F_SETLK; |
58 |
|
|
fl.l_type = F_WRLCK; |
59 |
|
|
break; |
60 |
|
|
case F_TEST: |
61 |
|
|
fl.l_type = F_WRLCK; |
62 |
|
|
if (fcntl(filedes, F_GETLK, &fl) == -1) |
63 |
|
|
return (-1); |
64 |
|
|
if (fl.l_type == F_UNLCK || fl.l_pid == getpid()) |
65 |
|
|
return (0); |
66 |
|
|
errno = EAGAIN; |
67 |
|
|
return (-1); |
68 |
|
|
/* NOTREACHED */ |
69 |
|
|
default: |
70 |
|
|
errno = EINVAL; |
71 |
|
|
return (-1); |
72 |
|
|
/* NOTREACHED */ |
73 |
|
|
} |
74 |
|
|
|
75 |
|
|
return (fcntl(filedes, cmd, &fl)); |
76 |
|
|
} |