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 /*
31 * ftruncate() and truncate() set a file to a specified
32 * length using fcntl(F_FREESP) system call. If the file
33 * was previously longer than length, the bytes past the
34 * length will no longer be accessible. If it was shorter,
35 * bytes not written will be zero filled.
36 */
37
38 #include <sys/feature_tests.h>
39
40 #if !defined(_LP64) && _FILE_OFFSET_BITS == 64
41 #pragma weak _ftruncate64 = ftruncate64
42 #pragma weak _truncate64 = truncate64
43 #define ftruncate ftruncate64
44 #define truncate truncate64
45 #endif /* !_LP64 && _FILE_OFFSET_BITS == 64 */
46
47 #include "lint.h"
48 #include <unistd.h>
49 #include <stdio.h>
50 #include <fcntl.h>
51 #include <pthread.h>
52 #include <sys/types.h>
53
54 int
ftruncate(int fildes,off_t len)55 ftruncate(int fildes, off_t len)
56 {
57 struct flock lck;
58
59 lck.l_whence = 0; /* offset l_start from beginning of file */
60 lck.l_start = len;
61 lck.l_type = F_WRLCK; /* setting a write lock */
62 lck.l_len = (off_t)0; /* until the end of the file address space */
63
64 if (fcntl(fildes, F_FREESP, &lck) == -1) {
65 return (-1);
66 }
67 return (0);
68 }
69
70 int
truncate(const char * path,off_t len)71 truncate(const char *path, off_t len)
72 {
73
74 int rval = 0;
75 int cancel_state;
76 int fd;
77
78 /*
79 * truncate() is not a cancellation point,
80 * even though it calls open() and close().
81 */
82 (void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancel_state);
83 if ((fd = open(path, O_WRONLY)) == -1 || ftruncate(fd, len) == -1)
84 rval = -1;
85 if (fd >= 0)
86 (void) close(fd);
87 (void) pthread_setcancelstate(cancel_state, NULL);
88 return (rval);
89 }
90