1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #if defined(LIBC_SCCS) && !defined(lint) 36 static char sccsid[] = "@(#)fgetln.c 8.2 (Berkeley) 1/2/94"; 37 #endif /* LIBC_SCCS and not lint */ 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include "namespace.h" 42 #include <errno.h> 43 #include <limits.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include "un-namespace.h" 48 #include "libc_private.h" 49 #include "local.h" 50 51 /* 52 * Expand the line buffer. Return -1 on error. 53 #ifdef notdef 54 * The `new size' does not account for a terminating '\0', 55 * so we add 1 here. 56 #endif 57 */ 58 int 59 __slbexpand(FILE *fp, size_t newsize) 60 { 61 void *p; 62 63 #ifdef notdef 64 ++newsize; 65 #endif 66 if (fp->_lb._size >= newsize) 67 return (0); 68 if (newsize > INT_MAX) { 69 errno = ENOMEM; 70 return (-1); 71 } 72 if ((p = realloc(fp->_lb._base, newsize)) == NULL) 73 return (-1); 74 fp->_lb._base = p; 75 fp->_lb._size = newsize; 76 return (0); 77 } 78 79 /* 80 * Get an input line. The returned pointer often (but not always) 81 * points into a stdio buffer. Fgetln does not alter the text of 82 * the returned line (which is thus not a C string because it will 83 * not necessarily end with '\0'), but does allow callers to modify 84 * it if they wish. Thus, we set __SMOD in case the caller does. 85 */ 86 char * 87 fgetln(FILE *fp, size_t *lenp) 88 { 89 unsigned char *p; 90 char *ret; 91 size_t len; 92 size_t off; 93 94 FLOCKFILE_CANCELSAFE(fp); 95 ORIENT(fp, -1); 96 /* make sure there is input */ 97 if (fp->_r <= 0 && __srefill(fp)) { 98 *lenp = 0; 99 ret = NULL; 100 goto end; 101 } 102 103 /* look for a newline in the input */ 104 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) != NULL) { 105 /* 106 * Found one. Flag buffer as modified to keep fseek from 107 * `optimising' a backward seek, in case the user stomps on 108 * the text. 109 */ 110 p++; /* advance over it */ 111 ret = (char *)fp->_p; 112 *lenp = len = p - fp->_p; 113 fp->_flags |= __SMOD; 114 fp->_r -= len; 115 fp->_p = p; 116 goto end; 117 } 118 119 /* 120 * We have to copy the current buffered data to the line buffer. 121 * As a bonus, though, we can leave off the __SMOD. 122 * 123 * OPTIMISTIC is length that we (optimistically) expect will 124 * accommodate the `rest' of the string, on each trip through the 125 * loop below. 126 */ 127 #define OPTIMISTIC 80 128 129 for (len = fp->_r, off = 0;; len += fp->_r) { 130 size_t diff; 131 132 /* 133 * Make sure there is room for more bytes. Copy data from 134 * file buffer to line buffer, refill file and look for 135 * newline. The loop stops only when we find a newline. 136 */ 137 if (__slbexpand(fp, len + OPTIMISTIC)) 138 goto error; 139 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 140 len - off); 141 off = len; 142 if (__srefill(fp)) { 143 if (__sfeof(fp)) 144 break; 145 goto error; 146 } 147 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) == NULL) 148 continue; 149 150 /* got it: finish up the line (like code above) */ 151 p++; 152 diff = p - fp->_p; 153 len += diff; 154 if (__slbexpand(fp, len)) 155 goto error; 156 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 157 diff); 158 fp->_r -= diff; 159 fp->_p = p; 160 break; 161 } 162 *lenp = len; 163 #ifdef notdef 164 fp->_lb._base[len] = '\0'; 165 #endif 166 ret = (char *)fp->_lb._base; 167 end: 168 FUNLOCKFILE_CANCELSAFE(); 169 return (ret); 170 171 error: 172 *lenp = 0; /* ??? */ 173 fp->_flags |= __SERR; 174 ret = NULL; 175 goto end; 176 } 177