1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 1997 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
28*0Sstevel@tonic-gate /*	  All Rights Reserved  	*/
29*0Sstevel@tonic-gate 
30*0Sstevel@tonic-gate /*
31*0Sstevel@tonic-gate  * Portions of this source code were derived from Berkeley 4.3 BSD
32*0Sstevel@tonic-gate  * under license from the Regents of the University of California.
33*0Sstevel@tonic-gate  */
34*0Sstevel@tonic-gate 
35*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
36*0Sstevel@tonic-gate 
37*0Sstevel@tonic-gate /*LINTLIBRARY*/
38*0Sstevel@tonic-gate 
39*0Sstevel@tonic-gate #include <sys/types.h>
40*0Sstevel@tonic-gate #include <sys/file.h>
41*0Sstevel@tonic-gate #include <fcntl.h>
42*0Sstevel@tonic-gate #include <errno.h>
43*0Sstevel@tonic-gate 
44*0Sstevel@tonic-gate int
45*0Sstevel@tonic-gate flock(int fd, int operation)
46*0Sstevel@tonic-gate {
47*0Sstevel@tonic-gate 	struct flock	fl;
48*0Sstevel@tonic-gate 	int	cmd;
49*0Sstevel@tonic-gate 	int	ret;
50*0Sstevel@tonic-gate 
51*0Sstevel@tonic-gate 	/* initialize the flock struct to set lock on entire file */
52*0Sstevel@tonic-gate 	fl.l_whence = 0;
53*0Sstevel@tonic-gate 	fl.l_start = 0;
54*0Sstevel@tonic-gate 	fl.l_len = 0;
55*0Sstevel@tonic-gate 	fl.l_type = 0;
56*0Sstevel@tonic-gate 
57*0Sstevel@tonic-gate 	/* In non-blocking lock, use F_SETLK for cmd, F_SETLKW otherwise */
58*0Sstevel@tonic-gate 	if (operation & LOCK_NB) {
59*0Sstevel@tonic-gate 		cmd = F_SETLK;
60*0Sstevel@tonic-gate 		operation &= ~LOCK_NB;	/* turn off this bit */
61*0Sstevel@tonic-gate 	} else
62*0Sstevel@tonic-gate 		cmd = F_SETLKW;
63*0Sstevel@tonic-gate 
64*0Sstevel@tonic-gate 	switch (operation) {
65*0Sstevel@tonic-gate 	case LOCK_UN:
66*0Sstevel@tonic-gate 		fl.l_type |= F_UNLCK;
67*0Sstevel@tonic-gate 		break;
68*0Sstevel@tonic-gate 	case LOCK_SH:
69*0Sstevel@tonic-gate 		fl.l_type |= F_RDLCK;
70*0Sstevel@tonic-gate 		break;
71*0Sstevel@tonic-gate 	case LOCK_EX:
72*0Sstevel@tonic-gate 		fl.l_type |= F_WRLCK;
73*0Sstevel@tonic-gate 		break;
74*0Sstevel@tonic-gate 	default:
75*0Sstevel@tonic-gate 		errno = EINVAL;
76*0Sstevel@tonic-gate 		return (-1);
77*0Sstevel@tonic-gate 	}
78*0Sstevel@tonic-gate 
79*0Sstevel@tonic-gate 	ret = fcntl(fd, cmd, &fl);
80*0Sstevel@tonic-gate 
81*0Sstevel@tonic-gate 	if (ret == -1 && errno == EACCES)
82*0Sstevel@tonic-gate 		errno = EWOULDBLOCK;
83*0Sstevel@tonic-gate 
84*0Sstevel@tonic-gate 	return (ret);
85*0Sstevel@tonic-gate }
86