Annotation of src/usr.bin/tail/read.c, Revision 1.9
1.9 ! kjell 1: /* $OpenBSD: read.c,v 1.8 2006/03/22 19:43:29 kjell Exp $ */
1.1 deraadt 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.
1.7 millert 19: * 3. Neither the name of the University nor the names of its contributors
1.1 deraadt 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
1.9 ! kjell 40: static char rcsid[] = "$OpenBSD: read.c,v 1.8 2006/03/22 19:43:29 kjell Exp $";
1.1 deraadt 41: #endif /* not lint */
42:
43: #include <sys/types.h>
44: #include <sys/stat.h>
1.8 kjell 45: #include <sys/limits.h>
1.3 millert 46:
47: #include <err.h>
48: #include <errno.h>
1.1 deraadt 49: #include <fcntl.h>
50: #include <stdio.h>
51: #include <stdlib.h>
52: #include <string.h>
1.3 millert 53: #include <unistd.h>
54:
1.1 deraadt 55: #include "extern.h"
56:
57: /*
58: * bytes -- read bytes to an offset from the end and display.
59: *
60: * This is the function that reads to a byte offset from the end of the input,
61: * storing the data in a wrap-around buffer which is then displayed. If the
62: * rflag is set, the data is displayed in lines in reverse order, and this
63: * routine has the usual nastiness of trying to find the newlines. Otherwise,
64: * it is displayed from the character closest to the beginning of the input to
65: * the end.
1.4 ericj 66: *
1.5 mpech 67: * A non-zero return means an (non-fatal) error occurred.
1.4 ericj 68: *
1.1 deraadt 69: */
1.4 ericj 70: int
1.9 ! kjell 71: bytes(FILE *fp, off_t off)
1.1 deraadt 72: {
1.8 kjell 73: int ch;
74: size_t len, tlen;
1.6 mpech 75: char *ep, *p, *t;
1.1 deraadt 76: int wrap;
77: char *sp;
78:
1.8 kjell 79: if (off > SIZE_T_MAX)
80: errx(1, "offset too large");
81:
1.1 deraadt 82: if ((sp = p = malloc(off)) == NULL)
1.3 millert 83: err(1, NULL);
1.1 deraadt 84:
85: for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) {
86: *p = ch;
87: if (++p == ep) {
88: wrap = 1;
89: p = sp;
90: }
91: }
92: if (ferror(fp)) {
93: ierr();
1.4 ericj 94: return(1);
1.1 deraadt 95: }
96:
97: if (rflag) {
98: for (t = p - 1, len = 0; t >= sp; --t, ++len)
99: if (*t == '\n' && len) {
100: WR(t + 1, len);
101: len = 0;
102: }
103: if (wrap) {
104: tlen = len;
105: for (t = ep - 1, len = 0; t >= p; --t, ++len)
106: if (*t == '\n') {
107: if (len) {
108: WR(t + 1, len);
109: len = 0;
110: }
111: if (tlen) {
112: WR(sp, tlen);
113: tlen = 0;
114: }
115: }
116: if (len)
117: WR(t + 1, len);
118: if (tlen)
119: WR(sp, tlen);
120: }
121: } else {
122: if (wrap && (len = ep - p))
123: WR(p, len);
1.3 millert 124: if ((len = p - sp))
1.1 deraadt 125: WR(sp, len);
126: }
1.4 ericj 127: return(0);
1.1 deraadt 128: }
129:
130: /*
131: * lines -- read lines to an offset from the end and display.
132: *
133: * This is the function that reads to a line offset from the end of the input,
134: * storing the data in an array of buffers which is then displayed. If the
135: * rflag is set, the data is displayed in lines in reverse order, and this
136: * routine has the usual nastiness of trying to find the newlines. Otherwise,
137: * it is displayed from the line closest to the beginning of the input to
138: * the end.
1.4 ericj 139: *
1.5 mpech 140: * A non-zero return means an (non-fatal) error occurred.
1.4 ericj 141: *
1.1 deraadt 142: */
1.4 ericj 143: int
1.9 ! kjell 144: lines(FILE *fp, off_t off)
1.1 deraadt 145: {
146: struct {
1.8 kjell 147: size_t blen;
148: size_t len;
1.1 deraadt 149: char *l;
150: } *lines;
1.6 mpech 151: int ch;
152: char *p = NULL;
1.8 kjell 153: int wrap;
154: size_t cnt, recno, blen, newsize;
155: char *sp = NULL, *newp = NULL;
156:
157: if (off > SIZE_T_MAX)
158: errx(1, "offset too large");
1.1 deraadt 159:
1.3 millert 160: if ((lines = calloc(off, sizeof(*lines))) == NULL)
161: err(1, NULL);
1.1 deraadt 162:
163: blen = cnt = recno = wrap = 0;
164:
165: while ((ch = getc(fp)) != EOF) {
166: if (++cnt > blen) {
1.8 kjell 167: newsize = blen + 1024;
168: if ((newp = realloc(sp, newsize)) == NULL)
1.3 millert 169: err(1, NULL);
1.8 kjell 170: sp = newp;
171: blen = newsize;
1.1 deraadt 172: p = sp + cnt - 1;
173: }
174: *p++ = ch;
175: if (ch == '\n') {
176: if (lines[recno].blen < cnt) {
1.8 kjell 177: newsize = cnt + 256;
178: if ((newp = realloc(lines[recno].l,
179: newsize)) == NULL)
1.3 millert 180: err(1, NULL);
1.8 kjell 181: lines[recno].l = newp;
182: lines[recno].blen = newsize;
1.1 deraadt 183: }
1.3 millert 184: memcpy(lines[recno].l, sp, (lines[recno].len = cnt));
1.1 deraadt 185: cnt = 0;
186: p = sp;
187: if (++recno == off) {
188: wrap = 1;
189: recno = 0;
190: }
191: }
192: }
193: if (ferror(fp)) {
194: ierr();
1.4 ericj 195: return(1);
1.1 deraadt 196: }
197: if (cnt) {
198: lines[recno].l = sp;
199: lines[recno].len = cnt;
200: if (++recno == off) {
201: wrap = 1;
202: recno = 0;
203: }
204: }
205:
206: if (rflag) {
1.8 kjell 207: for (cnt = recno; cnt > 0; --cnt)
208: WR(lines[cnt - 1].l, lines[cnt - 1].len);
1.1 deraadt 209: if (wrap)
1.8 kjell 210: for (cnt = off; cnt > recno; --cnt)
211: WR(lines[cnt - 1].l, lines[cnt - 1].len);
1.1 deraadt 212: } else {
213: if (wrap)
214: for (cnt = recno; cnt < off; ++cnt)
215: WR(lines[cnt].l, lines[cnt].len);
216: for (cnt = 0; cnt < recno; ++cnt)
217: WR(lines[cnt].l, lines[cnt].len);
218: }
1.4 ericj 219: return(0);
1.1 deraadt 220: }
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