/*
 * 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   */

/*
 * 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);
}