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