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) 341573Srgrimesstatic char sccsid[] = "@(#)fgets.c 8.2 (Berkeley) 12/22/93"; 351573Srgrimes#endif /* LIBC_SCCS and not lint */ 3692986Sobrien#include <sys/cdefs.h> 3792986Sobrien__FBSDID("$FreeBSD: stable/10/lib/libc/stdio/fgets.c 321074 2017-07-17 14:09:34Z kib $"); 381573Srgrimes 3971579Sdeischen#include "namespace.h" 40305583Sache#include <errno.h> 411573Srgrimes#include <stdio.h> 421573Srgrimes#include <string.h> 4371579Sdeischen#include "un-namespace.h" 4413545Sjulian#include "local.h" 4535129Sjb#include "libc_private.h" 461573Srgrimes 471573Srgrimes/* 481573Srgrimes * Read at most n-1 characters from the given file. 491573Srgrimes * Stop when a newline has been read, or the count runs out. 501573Srgrimes * Return first argument, or NULL if no characters were read. 511573Srgrimes */ 521573Srgrimeschar * 53249810Semastefgets(char * __restrict buf, int n, FILE * __restrict fp) 541573Srgrimes{ 5592889Sobrien size_t len; 56321074Skib char *s, *ret; 5792889Sobrien unsigned char *p, *t; 581573Srgrimes 59321074Skib FLOCKFILE_CANCELSAFE(fp); 60305583Sache ORIENT(fp, -1); 61305583Sache 62305583Sache if (n <= 0) { /* sanity check */ 63305583Sache fp->_flags |= __SERR; 64305583Sache errno = EINVAL; 65321074Skib ret = NULL; 66321074Skib goto end; 67305583Sache } 681573Srgrimes 691573Srgrimes s = buf; 701573Srgrimes n--; /* leave space for NUL */ 711573Srgrimes while (n != 0) { 721573Srgrimes /* 731573Srgrimes * If the buffer is empty, refill it. 741573Srgrimes */ 751573Srgrimes if ((len = fp->_r) <= 0) { 761573Srgrimes if (__srefill(fp)) { 771573Srgrimes /* EOF/error: stop with partial or no line */ 78305583Sache if (!__sfeof(fp) || s == buf) { 79321074Skib ret = NULL; 80321074Skib goto end; 8113545Sjulian } 821573Srgrimes break; 831573Srgrimes } 841573Srgrimes len = fp->_r; 851573Srgrimes } 861573Srgrimes p = fp->_p; 871573Srgrimes 881573Srgrimes /* 891573Srgrimes * Scan through at most n bytes of the current buffer, 901573Srgrimes * looking for '\n'. If found, copy up to and including 911573Srgrimes * newline, and stop. Otherwise, copy entire chunk 921573Srgrimes * and loop. 931573Srgrimes */ 941573Srgrimes if (len > n) 951573Srgrimes len = n; 961573Srgrimes t = memchr((void *)p, '\n', len); 971573Srgrimes if (t != NULL) { 981573Srgrimes len = ++t - p; 991573Srgrimes fp->_r -= len; 1001573Srgrimes fp->_p = t; 1011573Srgrimes (void)memcpy((void *)s, (void *)p, len); 1021573Srgrimes s[len] = 0; 103321074Skib ret = buf; 104321074Skib goto end; 1051573Srgrimes } 1061573Srgrimes fp->_r -= len; 1071573Srgrimes fp->_p += len; 1081573Srgrimes (void)memcpy((void *)s, (void *)p, len); 1091573Srgrimes s += len; 1101573Srgrimes n -= len; 1111573Srgrimes } 1121573Srgrimes *s = 0; 113321074Skib ret = buf; 114321074Skibend: 115321074Skib FUNLOCKFILE_CANCELSAFE(); 116321074Skib return (ret); 1171573Srgrimes} 118