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 #include "namespace.h" 36 #include <errno.h> 37 #include <limits.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include "un-namespace.h" 42 #include "libc_private.h" 43 #include "local.h" 44 45 /* 46 * Expand the line buffer. Return -1 on error. 47 */ 48 int 49 __slbexpand(FILE *fp, size_t newsize) 50 { 51 void *p; 52 53 if (fp->_lb._size >= newsize) 54 return (0); 55 if (newsize > INT_MAX) { 56 errno = ENOMEM; 57 return (-1); 58 } 59 if ((p = realloc(fp->_lb._base, newsize)) == NULL) 60 return (-1); 61 fp->_lb._base = p; 62 fp->_lb._size = newsize; 63 return (0); 64 } 65 66 /* 67 * Get an input line. The returned pointer often (but not always) 68 * points into a stdio buffer. Fgetln does not alter the text of 69 * the returned line (which is thus not a C string because it will 70 * not necessarily end with '\0'), but does allow callers to modify 71 * it if they wish. Thus, we set __SMOD in case the caller does. 72 */ 73 char * 74 fgetln(FILE *fp, size_t *lenp) 75 { 76 unsigned char *p; 77 char *ret; 78 size_t len; 79 size_t off; 80 81 FLOCKFILE_CANCELSAFE(fp); 82 ORIENT(fp, -1); 83 /* make sure there is input */ 84 if (fp->_r <= 0 && __srefill(fp)) { 85 *lenp = 0; 86 ret = NULL; 87 goto end; 88 } 89 90 /* look for a newline in the input */ 91 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) != NULL) { 92 /* 93 * Found one. Flag buffer as modified to keep fseek from 94 * `optimising' a backward seek, in case the user stomps on 95 * the text. 96 */ 97 p++; /* advance over it */ 98 ret = (char *)fp->_p; 99 *lenp = len = p - fp->_p; 100 fp->_flags |= __SMOD; 101 fp->_r -= len; 102 fp->_p = p; 103 goto end; 104 } 105 106 /* 107 * We have to copy the current buffered data to the line buffer. 108 * As a bonus, though, we can leave off the __SMOD. 109 * 110 * OPTIMISTIC is length that we (optimistically) expect will 111 * accommodate the `rest' of the string, on each trip through the 112 * loop below. 113 */ 114 #define OPTIMISTIC 80 115 116 for (len = fp->_r, off = 0;; len += fp->_r) { 117 size_t diff; 118 119 /* 120 * Make sure there is room for more bytes. Copy data from 121 * file buffer to line buffer, refill file and look for 122 * newline. The loop stops only when we find a newline. 123 */ 124 if (__slbexpand(fp, len + OPTIMISTIC)) 125 goto error; 126 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 127 len - off); 128 off = len; 129 if (__srefill(fp)) { 130 if (__sfeof(fp)) 131 break; 132 goto error; 133 } 134 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) == NULL) 135 continue; 136 137 /* got it: finish up the line (like code above) */ 138 p++; 139 diff = p - fp->_p; 140 len += diff; 141 if (__slbexpand(fp, len)) 142 goto error; 143 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 144 diff); 145 fp->_r -= diff; 146 fp->_p = p; 147 break; 148 } 149 *lenp = len; 150 ret = (char *)fp->_lb._base; 151 end: 152 FUNLOCKFILE_CANCELSAFE(); 153 return (ret); 154 155 error: 156 *lenp = 0; /* ??? */ 157 fp->_flags |= __SERR; 158 ret = NULL; 159 goto end; 160 } 161