1 /* $OpenBSD: read.c,v 1.20 2017/03/26 19:55:07 martijn 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
39 #include <err.h>
40 #include <stdio.h>
41 #include <stdint.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
bytes(struct tailfile * tf,off_t off)62 bytes(struct tailfile *tf, 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_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(tf->fp)) != EOF;) {
77 *p = ch;
78 if (++p == ep) {
79 wrap = 1;
80 p = sp;
81 }
82 }
83 if (ferror(tf->fp)) {
84 ierr(tf->fname);
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
lines(struct tailfile * tf,off_t off)138 lines(struct tailfile *tf, off_t off)
139 {
140 struct {
141 size_t blen;
142 size_t len;
143 char *l;
144 } *lines = NULL;
145 int ch, rc = 0;
146 char *p = NULL;
147 int wrap;
148 size_t cnt, lineno, nlineno, recno, blen, newsize;
149 char *sp = NULL, *newp = NULL;
150
151 if (off > SIZE_MAX)
152 errx(1, "offset too large");
153
154 lineno = blen = cnt = recno = wrap = 0;
155
156 while ((ch = getc(tf->fp)) != EOF) {
157 if (++cnt > blen) {
158 newsize = blen + 1024;
159 if ((newp = realloc(sp, newsize)) == NULL)
160 err(1, NULL);
161 sp = newp;
162 blen = newsize;
163 p = sp + cnt - 1;
164 }
165 *p++ = ch;
166 if (recno >= lineno) {
167 nlineno = (lineno + 1024) > off ?
168 (size_t) off : lineno + 1024;
169 if ((lines = recallocarray(lines, lineno, nlineno,
170 sizeof(*lines))) == NULL)
171 err(1, NULL);
172 lineno = nlineno;
173 }
174 if (ch == '\n') {
175 if (lines[recno].blen < cnt) {
176 newsize = cnt + 256;
177 if ((newp = realloc(lines[recno].l,
178 newsize)) == NULL)
179 err(1, NULL);
180 lines[recno].l = newp;
181 lines[recno].blen = newsize;
182 }
183 memcpy(lines[recno].l, sp, (lines[recno].len = cnt));
184 cnt = 0;
185 p = sp;
186 if (++recno == off) {
187 wrap = 1;
188 recno = 0;
189 }
190 }
191 }
192 if (ferror(tf->fp)) {
193 ierr(tf->fname);
194 rc = 1;
195 goto done;
196 }
197 if (cnt) {
198 lines[recno].l = sp;
199 lines[recno].len = cnt;
200 sp = NULL;
201 if (++recno == off) {
202 wrap = 1;
203 recno = 0;
204 }
205 }
206
207 if (rflag) {
208 for (cnt = recno; cnt > 0; --cnt)
209 WR(lines[cnt - 1].l, lines[cnt - 1].len);
210 if (wrap)
211 for (cnt = off; cnt > recno; --cnt)
212 WR(lines[cnt - 1].l, lines[cnt - 1].len);
213 } else {
214 if (wrap)
215 for (cnt = recno; cnt < off; ++cnt)
216 WR(lines[cnt].l, lines[cnt].len);
217 for (cnt = 0; cnt < recno; ++cnt)
218 WR(lines[cnt].l, lines[cnt].len);
219 }
220 done:
221 for (cnt = 0; cnt < lineno; cnt++)
222 free(lines[cnt].l);
223 free(sp);
224 free(lines);
225 return(rc);
226 }
227