xref: /titanic_41/usr/src/lib/libc/port/sys/lockf.c (revision 257873cfc1dd3337766407f80397db60a56f2f5a)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #include <sys/feature_tests.h>
33 
34 #if !defined(_LP64) && _FILE_OFFSET_BITS == 64
35 #define	__lockf		__lockf64
36 #endif
37 
38 #include "lint.h"
39 #include <sys/types.h>
40 #include <unistd.h>
41 #include <errno.h>
42 #include <fcntl.h>
43 
44 int
45 __lockf(int fildes, int function, off_t size)
46 {
47 	struct flock l;
48 	int rv;
49 
50 	l.l_whence = 1;
51 	if (size < 0) {
52 		l.l_start = size;
53 		l.l_len = -size;
54 	} else {
55 		l.l_start = (off_t)0;
56 		l.l_len = size;
57 	}
58 	switch (function) {
59 	case F_ULOCK:
60 		l.l_type = F_UNLCK;
61 		rv = fcntl(fildes, F_SETLK, &l);
62 		break;
63 	case F_LOCK:
64 		l.l_type = F_WRLCK;
65 		rv = fcntl(fildes, F_SETLKW, &l);
66 		break;
67 	case F_TLOCK:
68 		l.l_type = F_WRLCK;
69 		rv = fcntl(fildes, F_SETLK, &l);
70 		break;
71 	case F_TEST:
72 		l.l_type = F_WRLCK;
73 		rv = fcntl(fildes, F_GETLK, &l);
74 		if (rv != -1) {
75 			if (l.l_type == F_UNLCK)
76 				return (0);
77 			else {
78 				errno = EAGAIN;
79 				return (-1);
80 			}
81 		}
82 		break;
83 	default:
84 		errno = EINVAL;
85 		return (-1);
86 	}
87 	if (rv < 0) {
88 		switch (errno) {
89 		case EMFILE:
90 		case ENOSPC:
91 		case ENOLCK:
92 			/*
93 			 * A deadlock error is given if we run out of resources,
94 			 * in compliance with /usr/group standards.
95 			 */
96 			errno = EDEADLK;
97 			break;
98 		default:
99 			break;
100 		}
101 	}
102 	return (rv);
103 }
104