1 /* $OpenBSD: read.c,v 1.14 2009/10/27 23:59:44 deraadt Exp $ */ 2 /* $NetBSD: read.c,v 1.4 1994/11/23 07:42:07 jtc Exp $ */ 3 4 /*- 5 * Copyright (c) 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * Edward Sze-Tyan Wang. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/types.h> 37 #include <sys/stat.h> 38 #include <sys/limits.h> 39 40 #include <err.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <unistd.h> 45 46 #include "extern.h" 47 48 /* 49 * bytes -- read bytes to an offset from the end and display. 50 * 51 * This is the function that reads to a byte offset from the end of the input, 52 * storing the data in a wrap-around buffer which is then displayed. If the 53 * rflag is set, the data is displayed in lines in reverse order, and this 54 * routine has the usual nastiness of trying to find the newlines. Otherwise, 55 * it is displayed from the character closest to the beginning of the input to 56 * the end. 57 * 58 * A non-zero return means an (non-fatal) error occurred. 59 * 60 */ 61 int 62 bytes(FILE *fp, off_t off) 63 { 64 int ch; 65 size_t len, tlen; 66 char *ep, *p, *t; 67 int wrap; 68 char *sp; 69 70 if (off > SIZE_T_MAX) 71 errx(1, "offset too large"); 72 73 if ((sp = p = malloc(off)) == NULL) 74 err(1, NULL); 75 76 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) { 77 *p = ch; 78 if (++p == ep) { 79 wrap = 1; 80 p = sp; 81 } 82 } 83 if (ferror(fp)) { 84 ierr(); 85 free(sp); 86 return(1); 87 } 88 89 if (rflag) { 90 for (t = p - 1, len = 0; t >= sp; --t, ++len) 91 if (*t == '\n' && len) { 92 WR(t + 1, len); 93 len = 0; 94 } 95 if (wrap) { 96 tlen = len; 97 for (t = ep - 1, len = 0; t >= p; --t, ++len) 98 if (*t == '\n') { 99 if (len) { 100 WR(t + 1, len); 101 len = 0; 102 } 103 if (tlen) { 104 WR(sp, tlen); 105 tlen = 0; 106 } 107 } 108 if (len) 109 WR(t + 1, len); 110 if (tlen) 111 WR(sp, tlen); 112 } 113 } else { 114 if (wrap && (len = ep - p)) 115 WR(p, len); 116 if ((len = p - sp)) 117 WR(sp, len); 118 } 119 120 free(sp); 121 return(0); 122 } 123 124 /* 125 * lines -- read lines to an offset from the end and display. 126 * 127 * This is the function that reads to a line offset from the end of the input, 128 * storing the data in an array of buffers which is then displayed. If the 129 * rflag is set, the data is displayed in lines in reverse order, and this 130 * routine has the usual nastiness of trying to find the newlines. Otherwise, 131 * it is displayed from the line closest to the beginning of the input to 132 * the end. 133 * 134 * A non-zero return means an (non-fatal) error occurred. 135 * 136 */ 137 int 138 lines(FILE *fp, off_t off) 139 { 140 struct { 141 size_t blen; 142 size_t len; 143 char *l; 144 } *lines; 145 int ch, rc = 0; 146 char *p = NULL; 147 int wrap; 148 size_t cnt, recno, blen, newsize; 149 char *sp = NULL, *newp = NULL; 150 151 if (off > SIZE_T_MAX) 152 errx(1, "offset too large"); 153 154 if ((lines = calloc(off, sizeof(*lines))) == NULL) 155 err(1, NULL); 156 157 blen = cnt = recno = wrap = 0; 158 159 while ((ch = getc(fp)) != EOF) { 160 if (++cnt > blen) { 161 newsize = blen + 1024; 162 if ((newp = realloc(sp, newsize)) == NULL) 163 err(1, NULL); 164 sp = newp; 165 blen = newsize; 166 p = sp + cnt - 1; 167 } 168 *p++ = ch; 169 if (ch == '\n') { 170 if (lines[recno].blen < cnt) { 171 newsize = cnt + 256; 172 if ((newp = realloc(lines[recno].l, 173 newsize)) == NULL) 174 err(1, NULL); 175 lines[recno].l = newp; 176 lines[recno].blen = newsize; 177 } 178 memcpy(lines[recno].l, sp, (lines[recno].len = cnt)); 179 cnt = 0; 180 p = sp; 181 if (++recno == off) { 182 wrap = 1; 183 recno = 0; 184 } 185 } 186 } 187 if (ferror(fp)) { 188 ierr(); 189 rc = 1; 190 goto done; 191 } 192 if (cnt) { 193 lines[recno].l = sp; 194 lines[recno].len = cnt; 195 sp = NULL; 196 if (++recno == off) { 197 wrap = 1; 198 recno = 0; 199 } 200 } 201 202 if (rflag) { 203 for (cnt = recno; cnt > 0; --cnt) 204 WR(lines[cnt - 1].l, lines[cnt - 1].len); 205 if (wrap) 206 for (cnt = off; cnt > recno; --cnt) 207 WR(lines[cnt - 1].l, lines[cnt - 1].len); 208 } else { 209 if (wrap) 210 for (cnt = recno; cnt < off; ++cnt) 211 WR(lines[cnt].l, lines[cnt].len); 212 for (cnt = 0; cnt < recno; ++cnt) 213 WR(lines[cnt].l, lines[cnt].len); 214 } 215 done: 216 for (cnt = 0; cnt < off; cnt++) 217 free(lines[cnt].l); 218 free(sp); 219 free(lines); 220 return(rc); 221 } 222