ftell.c revision 290549
11573Srgrimes/*- 21573Srgrimes * Copyright (c) 1990, 1993 31573Srgrimes * The Regents of the University of California. All rights reserved. 41573Srgrimes * 51573Srgrimes * This code is derived from software contributed to Berkeley by 61573Srgrimes * Chris Torek. 71573Srgrimes * 81573Srgrimes * Redistribution and use in source and binary forms, with or without 91573Srgrimes * modification, are permitted provided that the following conditions 101573Srgrimes * are met: 111573Srgrimes * 1. Redistributions of source code must retain the above copyright 121573Srgrimes * notice, this list of conditions and the following disclaimer. 131573Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 141573Srgrimes * notice, this list of conditions and the following disclaimer in the 151573Srgrimes * documentation and/or other materials provided with the distribution. 16249808Semaste * 3. Neither the name of the University nor the names of its contributors 171573Srgrimes * may be used to endorse or promote products derived from this software 181573Srgrimes * without specific prior written permission. 191573Srgrimes * 201573Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 211573Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 221573Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 231573Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 241573Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 251573Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 261573Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 271573Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 281573Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 291573Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 301573Srgrimes * SUCH DAMAGE. 311573Srgrimes */ 321573Srgrimes 331573Srgrimes#if defined(LIBC_SCCS) && !defined(lint) 3423663Speterstatic char sccsid[] = "@(#)ftell.c 8.2 (Berkeley) 5/4/95"; 351573Srgrimes#endif /* LIBC_SCCS and not lint */ 3692986Sobrien#include <sys/cdefs.h> 3792986Sobrien__FBSDID("$FreeBSD: head/lib/libc/stdio/ftell.c 290549 2015-11-08 18:00:44Z ache $"); 381573Srgrimes 3971579Sdeischen#include "namespace.h" 4043782Sdt#include <sys/types.h> 4182588Sache#include <errno.h> 42268997Sache#include <fcntl.h> 4382588Sache#include <limits.h> 441573Srgrimes#include <stdio.h> 4571579Sdeischen#include "un-namespace.h" 461573Srgrimes#include "local.h" 4735129Sjb#include "libc_private.h" 481573Srgrimes 491573Srgrimes/* 5043782Sdt * standard ftell function. 511573Srgrimes */ 521573Srgrimeslong 53249810Semasteftell(FILE *fp) 541573Srgrimes{ 5592889Sobrien off_t rv; 5682588Sache 5743782Sdt rv = ftello(fp); 5882588Sache if (rv > LONG_MAX) { 5943782Sdt errno = EOVERFLOW; 6043782Sdt return (-1); 6143782Sdt } 6243782Sdt return (rv); 6343782Sdt} 6443782Sdt 6543782Sdt/* 6643782Sdt * ftello: return current offset. 6743782Sdt */ 6843782Sdtoff_t 69249810Semasteftello(FILE *fp) 7043782Sdt{ 7182709Sache fpos_t rv; 7282709Sache int ret; 7382668Sache 7482668Sache FLOCKFILE(fp); 7582709Sache ret = _ftello(fp, &rv); 7682668Sache FUNLOCKFILE(fp); 7782709Sache if (ret) 7882709Sache return (-1); 7982736Sache if (rv < 0) { /* Unspecified value because of ungetc() at 0 */ 8082736Sache errno = ESPIPE; 8182736Sache return (-1); 8282736Sache } 8382668Sache return (rv); 8482668Sache} 8582668Sache 8682709Sacheint 87249810Semaste_ftello(FILE *fp, fpos_t *offset) 8882668Sache{ 8992889Sobrien fpos_t pos; 9082588Sache size_t n; 911573Srgrimes 921573Srgrimes if (fp->_seek == NULL) { 931573Srgrimes errno = ESPIPE; /* historic practice */ 9482709Sache return (1); 951573Srgrimes } 961573Srgrimes 971573Srgrimes /* 981573Srgrimes * Find offset of underlying I/O object, then 991573Srgrimes * adjust for buffered bytes. 1001573Srgrimes */ 101290549Sache if (!(fp->_flags & __SRD) && (fp->_flags & __SWR) && 102290549Sache fp->_p != NULL && fp->_p - fp->_bf._base > 0 && 103290549Sache ((fp->_flags & __SAPP) || (fp->_flags2 & __S2OAP))) { 104290549Sache if ((pos = _sseek(fp, (fpos_t)0, SEEK_END)) == -1) { 105290549Sache if (errno == ESPIPE || 106290549Sache (fp->_flags & __SOPT) || __sflush(fp) || 107290549Sache (pos = _sseek(fp, (fpos_t)0, SEEK_CUR)) == -1) 108290549Sache return (1); 109290549Sache else { 110290549Sache *offset = pos; 111290549Sache return (0); 112290549Sache } 113290549Sache } 114290549Sache } else if (fp->_flags & __SOFF) 1151573Srgrimes pos = fp->_offset; 11682734Sache else { 11782807Sache pos = _sseek(fp, (fpos_t)0, SEEK_CUR); 11882668Sache if (pos == -1) 11982709Sache return (1); 1201573Srgrimes } 1211573Srgrimes if (fp->_flags & __SRD) { 1221573Srgrimes /* 1231573Srgrimes * Reading. Any unread characters (including 1241573Srgrimes * those from ungetc) cause the position to be 1251573Srgrimes * smaller than that in the underlying object. 1261573Srgrimes */ 12782709Sache if ((pos -= (HASUB(fp) ? fp->_ur : fp->_r)) < 0) { 12882734Sache fp->_flags |= __SERR; 12982734Sache errno = EIO; 13082734Sache return (1); 13182588Sache } 13282709Sache if (HASUB(fp)) 13382709Sache pos -= fp->_r; /* Can be negative at this point. */ 134290232Sache } else if ((fp->_flags & __SWR) && fp->_p != NULL && 135290232Sache (n = fp->_p - fp->_bf._base) > 0) { 136290230Sache /* 137290230Sache * Writing. Any buffered characters cause the 138290230Sache * position to be greater than that in the 139290230Sache * underlying object. 140290230Sache */ 141290231Sache if (pos > OFF_MAX - n) { 142290231Sache errno = EOVERFLOW; 143290231Sache return (1); 144290231Sache } 14582588Sache pos += n; 1461573Srgrimes } 14782709Sache *offset = pos; 14882709Sache return (0); 1491573Srgrimes} 150