1 /*- 2 * Copyright (c) 1991, 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 * Edward Sze-Tyan Wang. 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)read.c 8.1 (Berkeley) 6/6/93 37 * $FreeBSD: src/usr.bin/tail/read.c,v 1.6.8.1 2001/01/24 08:41:14 ru Exp $ 38 * $DragonFly: src/usr.bin/tail/read.c,v 1.3 2003/10/04 20:36:52 hmp Exp $ 39 */ 40 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 #include <fcntl.h> 44 #include <errno.h> 45 #include <unistd.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <err.h> 50 #include "extern.h" 51 52 /* 53 * bytes -- read bytes to an offset from the end and display. 54 * 55 * This is the function that reads to a byte offset from the end of the input, 56 * storing the data in a wrap-around buffer which is then displayed. If the 57 * rflag is set, the data is displayed in lines in reverse order, and this 58 * routine has the usual nastiness of trying to find the newlines. Otherwise, 59 * it is displayed from the character closest to the beginning of the input to 60 * the end. 61 */ 62 int 63 bytes(FILE *fp, off_t off) 64 { 65 int ch, len, tlen; 66 char *ep, *p, *t; 67 int wrap; 68 char *sp; 69 70 if ((sp = p = malloc(off)) == NULL) 71 err(1, "malloc"); 72 73 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) { 74 *p = ch; 75 if (++p == ep) { 76 wrap = 1; 77 p = sp; 78 } 79 } 80 if (ferror(fp)) { 81 ierr(); 82 return 1; 83 } 84 85 if (rflag) { 86 for (t = p - 1, len = 0; t >= sp; --t, ++len) 87 if (*t == '\n' && len) { 88 WR(t + 1, len); 89 len = 0; 90 } 91 if (wrap) { 92 tlen = len; 93 for (t = ep - 1, len = 0; t >= p; --t, ++len) 94 if (*t == '\n') { 95 if (len) { 96 WR(t + 1, len); 97 len = 0; 98 } 99 if (tlen) { 100 WR(sp, tlen); 101 tlen = 0; 102 } 103 } 104 if (len) 105 WR(t + 1, len); 106 if (tlen) 107 WR(sp, tlen); 108 } 109 } else { 110 if (wrap && (len = ep - p)) 111 WR(p, len); 112 if (len = p - sp) 113 WR(sp, len); 114 } 115 return 0; 116 } 117 118 /* 119 * lines -- read lines to an offset from the end and display. 120 * 121 * This is the function that reads to a line offset from the end of the input, 122 * storing the data in an array of buffers which is then displayed. If the 123 * rflag is set, the data is displayed in lines in reverse order, and this 124 * routine has the usual nastiness of trying to find the newlines. Otherwise, 125 * it is displayed from the line closest to the beginning of the input to 126 * the end. 127 */ 128 int 129 lines(FILE *fp, off_t off) 130 { 131 struct { 132 u_int blen; 133 u_int len; 134 char *l; 135 } *lines; 136 int ch; 137 char *p; 138 int blen, cnt, recno, wrap; 139 char *sp; 140 141 if ((lines = malloc(off * sizeof(*lines))) == NULL) 142 err(1, "malloc"); 143 bzero(lines, off * sizeof(*lines)); 144 sp = NULL; 145 blen = cnt = recno = wrap = 0; 146 147 while ((ch = getc(fp)) != EOF) { 148 if (++cnt > blen) { 149 if ((sp = realloc(sp, blen += 1024)) == NULL) 150 err(1, "realloc"); 151 p = sp + cnt - 1; 152 } 153 *p++ = ch; 154 if (ch == '\n') { 155 if (lines[recno].blen < cnt) { 156 lines[recno].blen = cnt + 256; 157 if ((lines[recno].l = realloc(lines[recno].l, 158 lines[recno].blen)) == NULL) 159 err(1, "realloc"); 160 } 161 bcopy(sp, lines[recno].l, lines[recno].len = cnt); 162 cnt = 0; 163 p = sp; 164 if (++recno == off) { 165 wrap = 1; 166 recno = 0; 167 } 168 } 169 } 170 if (ferror(fp)) { 171 ierr(); 172 return 1; 173 } 174 if (cnt) { 175 lines[recno].l = sp; 176 lines[recno].len = cnt; 177 if (++recno == off) { 178 wrap = 1; 179 recno = 0; 180 } 181 } 182 183 if (rflag) { 184 for (cnt = recno - 1; cnt >= 0; --cnt) 185 WR(lines[cnt].l, lines[cnt].len); 186 if (wrap) 187 for (cnt = off - 1; cnt >= recno; --cnt) 188 WR(lines[cnt].l, lines[cnt].len); 189 } else { 190 if (wrap) 191 for (cnt = recno; cnt < off; ++cnt) 192 WR(lines[cnt].l, lines[cnt].len); 193 for (cnt = 0; cnt < recno; ++cnt) 194 WR(lines[cnt].l, lines[cnt].len); 195 } 196 return 0; 197 } 198