/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

/*	Copyright (c) 1988 AT&T	*/

/*	  All Rights Reserved  	*/

#pragma ident	"%Z%%M%	%I%	%E% SMI"

/*

 * ftruncate() and truncate() set a file to a specified

 * length using fcntl(F_FREESP) system call. If the file

 * was previously longer than length, the bytes past the

 * length will no longer be accessible. If it was shorter,

 * bytes not written will be zero filled.

 */

#include <sys/feature_tests.h>

#if !defined(_LP64) && _FILE_OFFSET_BITS == 64

#pragma weak _ftruncate64 = ftruncate64

#pragma weak _truncate64 = truncate64

#define	ftruncate	ftruncate64

#define	truncate	truncate64

#endif /* !_LP64 && _FILE_OFFSET_BITS == 64 */

#include "lint.h"

#include <unistd.h>

#include <stdio.h>

#include <fcntl.h>

#include <pthread.h>

#include <sys/types.h>

int

ftruncate(int fildes, off_t len)

{

	struct flock lck;

	lck.l_whence = 0;	/* offset l_start from beginning of file */

	lck.l_start = len;

	lck.l_type = F_WRLCK;	/* setting a write lock */

	lck.l_len = (off_t)0;	/* until the end of the file address space */

	if (fcntl(fildes, F_FREESP, &lck) == -1) {

		return (-1);

	}

	return (0);

}

int

truncate(const char *path, off_t len)

{

	int rval = 0;

	int cancel_state;

	int fd;

	/*

	 * truncate() is not a cancellation point,

	 * even though it calls open() and close().

	 */

	(void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancel_state);

	if ((fd = open(path, O_WRONLY)) == -1 || ftruncate(fd, len) == -1)

		rval = -1;

	if (fd >= 0)

		(void) close(fd);

	(void) pthread_setcancelstate(cancel_state, NULL);

	return (rval);

}