xref: /onnv-gate/usr/src/cmd/mailx/lock.c (revision 0:68f95e015346)
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 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
23*0Sstevel@tonic-gate /*	  All Rights Reserved  	*/
24*0Sstevel@tonic-gate 
25*0Sstevel@tonic-gate 
26*0Sstevel@tonic-gate /*
27*0Sstevel@tonic-gate  * University Copyright- Copyright (c) 1982, 1986, 1988
28*0Sstevel@tonic-gate  * The Regents of the University of California
29*0Sstevel@tonic-gate  * All Rights Reserved
30*0Sstevel@tonic-gate  *
31*0Sstevel@tonic-gate  * University Acknowledgment- Portions of this document are derived from
32*0Sstevel@tonic-gate  * software developed by the University of California, Berkeley, and its
33*0Sstevel@tonic-gate  * contributors.
34*0Sstevel@tonic-gate  */
35*0Sstevel@tonic-gate 
36*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
37*0Sstevel@tonic-gate 
38*0Sstevel@tonic-gate /*
39*0Sstevel@tonic-gate  * lock a file pointer
40*0Sstevel@tonic-gate  */
41*0Sstevel@tonic-gate 
42*0Sstevel@tonic-gate #include <stdio.h>
43*0Sstevel@tonic-gate #include <string.h>
44*0Sstevel@tonic-gate #include <fcntl.h>
45*0Sstevel@tonic-gate 
46*0Sstevel@tonic-gate int
lock(FILE * fp,char * mode,int blk)47*0Sstevel@tonic-gate lock(FILE *fp, char *mode, int blk)
48*0Sstevel@tonic-gate {
49*0Sstevel@tonic-gate 	struct flock	l;
50*0Sstevel@tonic-gate 
51*0Sstevel@tonic-gate 	l.l_type = !strcmp(mode, "r") ? F_RDLCK : F_WRLCK;
52*0Sstevel@tonic-gate 	l.l_whence = 0;
53*0Sstevel@tonic-gate 	l.l_start = l.l_len = 0L;
54*0Sstevel@tonic-gate 	return fcntl(fileno(fp), blk ? F_SETLKW : F_SETLK, &l);
55*0Sstevel@tonic-gate }
56