xref: /titanic_41/usr/src/lib/libbc/libc/sys/common/ftruncate.c (revision 45916cd2fec6e79bca5dee0421bd39e3c2910d1e)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright (c) 1999 by Sun Microsystems, Inc.
24  * All rights reserved.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <syscall.h>
30 #include <sys/types.h>
31 
32 /* The following are from SVR4 sys/fcntl.h */
33 
34 #define F_FREESP 11	/* Free file space */
35 #define F_WRLCK	 02	/* Write Lock */
36 
37 /* lock structure from SVR4. */
38 struct fl {
39 	short l_type;
40 	short l_whence;
41 	off_t l_start;
42 	off_t l_len;
43 	long  l_sysid;
44 	pid_t l_pid;
45 	long  pad[4];
46 };
47 
48 int ftruncate(int fd, off_t length)
49 {
50 
51 	struct fl lck;
52 
53 	lck.l_whence = 0;	/* offset l_start from beginning of file */
54 	lck.l_start = length;
55 	lck.l_type = F_WRLCK;	/* setting a write lock */
56 	lck.l_len = 0L;
57 
58 	if (_syscall(SYS_fcntl, fd, F_FREESP, (int)&lck) == -1)
59 		return (-1);
60 	else
61 		return (0);
62 }
63