1 /* $OpenBSD: read.c,v 1.13 2008/06/02 06:01:15 otto 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 #ifndef lint 37 #if 0 38 static char sccsid[] = "@(#)read.c 8.1 (Berkeley) 6/6/93"; 39 #endif 40 static char rcsid[] = "$OpenBSD: read.c,v 1.13 2008/06/02 06:01:15 otto Exp $"; 41 #endif /* not lint */ 42 43 #include <sys/types.h> 44 #include <sys/stat.h> 45 #include <sys/limits.h> 46 47 #include <err.h> 48 #include <stdio.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <unistd.h> 52 53 #include "extern.h" 54 55 /* 56 * bytes -- read bytes to an offset from the end and display. 57 * 58 * This is the function that reads to a byte offset from the end of the input, 59 * storing the data in a wrap-around buffer which is then displayed. If the 60 * rflag is set, the data is displayed in lines in reverse order, and this 61 * routine has the usual nastiness of trying to find the newlines. Otherwise, 62 * it is displayed from the character closest to the beginning of the input to 63 * the end. 64 * 65 * A non-zero return means an (non-fatal) error occurred. 66 * 67 */ 68 int 69 bytes(FILE *fp, off_t off) 70 { 71 int ch; 72 size_t len, tlen; 73 char *ep, *p, *t; 74 int wrap; 75 char *sp; 76 77 if (off > SIZE_T_MAX) 78 errx(1, "offset too large"); 79 80 if ((sp = p = malloc(off)) == NULL) 81 err(1, NULL); 82 83 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) { 84 *p = ch; 85 if (++p == ep) { 86 wrap = 1; 87 p = sp; 88 } 89 } 90 if (ferror(fp)) { 91 ierr(); 92 free(sp); 93 return(1); 94 } 95 96 if (rflag) { 97 for (t = p - 1, len = 0; t >= sp; --t, ++len) 98 if (*t == '\n' && len) { 99 WR(t + 1, len); 100 len = 0; 101 } 102 if (wrap) { 103 tlen = len; 104 for (t = ep - 1, len = 0; t >= p; --t, ++len) 105 if (*t == '\n') { 106 if (len) { 107 WR(t + 1, len); 108 len = 0; 109 } 110 if (tlen) { 111 WR(sp, tlen); 112 tlen = 0; 113 } 114 } 115 if (len) 116 WR(t + 1, len); 117 if (tlen) 118 WR(sp, tlen); 119 } 120 } else { 121 if (wrap && (len = ep - p)) 122 WR(p, len); 123 if ((len = p - sp)) 124 WR(sp, len); 125 } 126 127 free(sp); 128 return(0); 129 } 130 131 /* 132 * lines -- read lines to an offset from the end and display. 133 * 134 * This is the function that reads to a line offset from the end of the input, 135 * storing the data in an array of buffers which is then displayed. If the 136 * rflag is set, the data is displayed in lines in reverse order, and this 137 * routine has the usual nastiness of trying to find the newlines. Otherwise, 138 * it is displayed from the line closest to the beginning of the input to 139 * the end. 140 * 141 * A non-zero return means an (non-fatal) error occurred. 142 * 143 */ 144 int 145 lines(FILE *fp, off_t off) 146 { 147 struct { 148 size_t blen; 149 size_t len; 150 char *l; 151 } *lines; 152 int ch, rc = 0; 153 char *p = NULL; 154 int wrap; 155 size_t cnt, recno, blen, newsize; 156 char *sp = NULL, *newp = NULL; 157 158 if (off > SIZE_T_MAX) 159 errx(1, "offset too large"); 160 161 if ((lines = calloc(off, sizeof(*lines))) == NULL) 162 err(1, NULL); 163 164 blen = cnt = recno = wrap = 0; 165 166 while ((ch = getc(fp)) != EOF) { 167 if (++cnt > blen) { 168 newsize = blen + 1024; 169 if ((newp = realloc(sp, newsize)) == NULL) 170 err(1, NULL); 171 sp = newp; 172 blen = newsize; 173 p = sp + cnt - 1; 174 } 175 *p++ = ch; 176 if (ch == '\n') { 177 if (lines[recno].blen < cnt) { 178 newsize = cnt + 256; 179 if ((newp = realloc(lines[recno].l, 180 newsize)) == NULL) 181 err(1, NULL); 182 lines[recno].l = newp; 183 lines[recno].blen = newsize; 184 } 185 memcpy(lines[recno].l, sp, (lines[recno].len = cnt)); 186 cnt = 0; 187 p = sp; 188 if (++recno == off) { 189 wrap = 1; 190 recno = 0; 191 } 192 } 193 } 194 if (ferror(fp)) { 195 ierr(); 196 rc = 1; 197 goto done; 198 } 199 if (cnt) { 200 lines[recno].l = sp; 201 lines[recno].len = cnt; 202 sp = NULL; 203 if (++recno == off) { 204 wrap = 1; 205 recno = 0; 206 } 207 } 208 209 if (rflag) { 210 for (cnt = recno; cnt > 0; --cnt) 211 WR(lines[cnt - 1].l, lines[cnt - 1].len); 212 if (wrap) 213 for (cnt = off; cnt > recno; --cnt) 214 WR(lines[cnt - 1].l, lines[cnt - 1].len); 215 } else { 216 if (wrap) 217 for (cnt = recno; cnt < off; ++cnt) 218 WR(lines[cnt].l, lines[cnt].len); 219 for (cnt = 0; cnt < recno; ++cnt) 220 WR(lines[cnt].l, lines[cnt].len); 221 } 222 done: 223 for (cnt = 0; cnt < off; cnt++) 224 free(lines[cnt].l); 225 free(sp); 226 free(lines); 227 return(rc); 228 } 229