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      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 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     31 
     32 /*
     33  * Seek for standard library.  Coordinates with buffering.
     34  */
     35 
     36 #pragma weak _fseek = fseek
     37 
     38 #include "lint.h"
     39 #include "file64.h"
     40 #include "mtlib.h"
     41 #include <stdio.h>
     42 #include <errno.h>
     43 #include <thread.h>
     44 #include <synch.h>
     45 #include <unistd.h>
     46 #include <sys/types.h>
     47 #include "stdiom.h"
     48 
     49 int
     50 fseek(FILE *iop, long offset, int ptrname)
     51 {
     52 	off_t	p;
     53 	rmutex_t *lk;
     54 
     55 	FLOCKFILE(lk, iop);
     56 	iop->_flag &= ~_IOEOF;
     57 
     58 	if (!(iop->_flag & _IOREAD) && !(iop->_flag & (_IOWRT | _IORW))) {
     59 		errno = EBADF;
     60 		FUNLOCKFILE(lk);
     61 		return (-1);
     62 	}
     63 
     64 	if (iop->_flag & _IOREAD) {
     65 		if (ptrname == 1 && iop->_base && !(iop->_flag&_IONBF)) {
     66 			offset -= iop->_cnt;
     67 		}
     68 	} else if (iop->_flag & (_IOWRT | _IORW)) {
     69 		if (_fflush_u(iop) == EOF) {
     70 			FUNLOCKFILE(lk);
     71 			return (-1);
     72 		}
     73 	}
     74 	iop->_cnt = 0;
     75 	iop->_ptr = iop->_base;
     76 	if (iop->_flag & _IORW) {
     77 		iop->_flag &= ~(_IOREAD | _IOWRT);
     78 	}
     79 	p = lseek(FILENO(iop), (off_t)offset, ptrname);
     80 	FUNLOCKFILE(lk);
     81 	return ((p == (off_t)-1) ? -1: 0);
     82 }
     83