xref: /onnv-gate/usr/src/lib/libc/port/stdio/ftell.c (revision 6812:febeba71273d)
10Sstevel@tonic-gate /*
20Sstevel@tonic-gate  * CDDL HEADER START
30Sstevel@tonic-gate  *
40Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*6812Sraf  * Common Development and Distribution License (the "License").
6*6812Sraf  * You may not use this file except in compliance with the License.
70Sstevel@tonic-gate  *
80Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
90Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
100Sstevel@tonic-gate  * See the License for the specific language governing permissions
110Sstevel@tonic-gate  * and limitations under the License.
120Sstevel@tonic-gate  *
130Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
140Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
150Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
160Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
170Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
180Sstevel@tonic-gate  *
190Sstevel@tonic-gate  * CDDL HEADER END
200Sstevel@tonic-gate  */
21*6812Sraf 
220Sstevel@tonic-gate /*
23*6812Sraf  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
240Sstevel@tonic-gate  * Use is subject to license terms.
250Sstevel@tonic-gate  */
260Sstevel@tonic-gate 
270Sstevel@tonic-gate /*	Copyright (c) 1988 AT&T	*/
280Sstevel@tonic-gate /*	  All Rights Reserved  	*/
290Sstevel@tonic-gate 
30*6812Sraf #pragma ident	"%Z%%M%	%I%	%E% SMI"
310Sstevel@tonic-gate 
320Sstevel@tonic-gate /*
330Sstevel@tonic-gate  * Return file offset.
340Sstevel@tonic-gate  * Coordinates with buffering.
350Sstevel@tonic-gate  */
36*6812Sraf #pragma weak _ftell = ftell
370Sstevel@tonic-gate 
38*6812Sraf #include "lint.h"
390Sstevel@tonic-gate #include "file64.h"
400Sstevel@tonic-gate #include "mtlib.h"
410Sstevel@tonic-gate #include <fcntl.h>
420Sstevel@tonic-gate #include <stdio.h>
430Sstevel@tonic-gate #include <thread.h>
440Sstevel@tonic-gate #include <synch.h>
450Sstevel@tonic-gate #include <errno.h>
460Sstevel@tonic-gate #include <unistd.h>
470Sstevel@tonic-gate #include <stddef.h>
480Sstevel@tonic-gate #include <limits.h>
490Sstevel@tonic-gate #include <sys/types.h>
500Sstevel@tonic-gate #include "stdiom.h"
510Sstevel@tonic-gate 
520Sstevel@tonic-gate long
ftell(FILE * iop)530Sstevel@tonic-gate ftell(FILE *iop)
540Sstevel@tonic-gate {
550Sstevel@tonic-gate 	ptrdiff_t adjust;
560Sstevel@tonic-gate 	off64_t	tres;
570Sstevel@tonic-gate 	rmutex_t *lk;
580Sstevel@tonic-gate 
590Sstevel@tonic-gate 	FLOCKFILE(lk, iop);
600Sstevel@tonic-gate 	if (iop->_cnt < 0)
610Sstevel@tonic-gate 		iop->_cnt = 0;
620Sstevel@tonic-gate 	if (iop->_flag & _IOREAD)
630Sstevel@tonic-gate 		adjust = (ptrdiff_t)-iop->_cnt;
640Sstevel@tonic-gate 	else if (iop->_flag & (_IOWRT | _IORW)) {
650Sstevel@tonic-gate 		adjust = 0;
660Sstevel@tonic-gate 		if (((iop->_flag & (_IOWRT | _IONBF)) == _IOWRT) &&
67*6812Sraf 		    (iop->_base != 0))
680Sstevel@tonic-gate 			adjust = iop->_ptr - iop->_base;
690Sstevel@tonic-gate 		else if ((iop->_flag & _IORW) && (iop->_base != 0))
700Sstevel@tonic-gate 			adjust = (ptrdiff_t)-iop->_cnt;
710Sstevel@tonic-gate 	} else {
720Sstevel@tonic-gate 		errno = EBADF;	/* file descriptor refers to no open file */
730Sstevel@tonic-gate 		FUNLOCKFILE(lk);
740Sstevel@tonic-gate 		return (EOF);
750Sstevel@tonic-gate 	}
760Sstevel@tonic-gate 
770Sstevel@tonic-gate 	tres = lseek64(FILENO(iop), 0, SEEK_CUR);
780Sstevel@tonic-gate 	if (tres >= 0)
790Sstevel@tonic-gate 		tres += adjust;
800Sstevel@tonic-gate 
810Sstevel@tonic-gate 	if (tres > LONG_MAX) {
820Sstevel@tonic-gate 		errno = EOVERFLOW;
830Sstevel@tonic-gate 		FUNLOCKFILE(lk);
840Sstevel@tonic-gate 		return (EOF);
850Sstevel@tonic-gate 	}
860Sstevel@tonic-gate 
870Sstevel@tonic-gate 	FUNLOCKFILE(lk);
880Sstevel@tonic-gate 	return ((long)tres);
890Sstevel@tonic-gate }
90