fseek.c revision 7257d1b4d25bfac0c802847390e98a464fd787ac
/*
* 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"
/*
* Seek for standard library. Coordinates with buffering.
*/
#pragma weak _fseek = fseek
#include "lint.h"
#include "file64.h"
#include "mtlib.h"
#include <stdio.h>
#include <errno.h>
#include <thread.h>
#include <synch.h>
#include <unistd.h>
#include <sys/types.h>
#include "stdiom.h"
int
fseek(FILE *iop, long offset, int ptrname)
{
off_t p;
rmutex_t *lk;
FLOCKFILE(lk, iop);
iop->_flag &= ~_IOEOF;
if (!(iop->_flag & _IOREAD) && !(iop->_flag & (_IOWRT | _IORW))) {
errno = EBADF;
FUNLOCKFILE(lk);
return (-1);
}
if (iop->_flag & _IOREAD) {
if (ptrname == 1 && iop->_base && !(iop->_flag&_IONBF)) {
offset -= iop->_cnt;
}
} else if (iop->_flag & (_IOWRT | _IORW)) {
if (_fflush_u(iop) == EOF) {
FUNLOCKFILE(lk);
return (-1);
}
}
iop->_cnt = 0;
iop->_ptr = iop->_base;
if (iop->_flag & _IORW) {
iop->_flag &= ~(_IOREAD | _IOWRT);
}
p = lseek(FILENO(iop), (off_t)offset, ptrname);
FUNLOCKFILE(lk);
return ((p == (off_t)-1) ? -1: 0);
}