blob: 10b5cd7a7d120c3a38351827e50ae35a64d232cf [file] [log] [blame]
Erik Andersene49d5ec2000-02-08 19:58:47 +00001/* vi: set sw=4 ts=4: */
Matt Kraai55bccf32001-01-05 02:57:53 +00002/*
3 * Mini tail implementation for busybox
4 *
Matt Kraai55bccf32001-01-05 02:57:53 +00005 * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 *
Erik Andersen3fe39dc2000-01-25 18:13:53 +000021 */
Matt Kraai55bccf32001-01-05 02:57:53 +000022
Manuel Novoa III cad53642003-03-19 09:13:01 +000023/* BB_AUDIT SUSv3 compliant (need fancy for -c) */
24/* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */
25/* http://www.opengroup.org/onlinepubs/007904975/utilities/tail.html */
Eric Andersenabc0f4f1999-12-08 23:19:36 +000026
Manuel Novoa III cad53642003-03-19 09:13:01 +000027/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
28 *
29 * Pretty much rewritten to fix numerous bugs and reduce realloc() calls.
30 * Bugs fixed (although I may have forgotten one or two... it was pretty bad)
31 * 1) mixing printf/write without fflush()ing stdout
32 * 2) no check that any open files are present
33 * 3) optstring had -q taking an arg
34 * 4) no error checking on write in some cases, and a warning even then
35 * 5) q and s interaction bug
36 * 6) no check for lseek error
37 * 7) lseek attempted when count==0 even if arg was +0 (from top)
38 */
39
40#include <stdio.h>
41#include <stdlib.h>
Eric Andersened3ef502001-01-27 08:24:39 +000042#include <string.h>
Robert Griebl53146cc2002-05-27 22:24:53 +000043#include <ctype.h>
Eric Andersened3ef502001-01-27 08:24:39 +000044#include <unistd.h>
Manuel Novoa III cad53642003-03-19 09:13:01 +000045#include <fcntl.h>
46#include <sys/stat.h>
Eric Andersencbe31da2001-02-20 06:14:08 +000047#include "busybox.h"
Eric Andersenabc0f4f1999-12-08 23:19:36 +000048
Matt Kraaia164c642001-02-05 17:50:03 +000049static const struct suffix_mult tail_suffixes[] = {
Matt Kraai24ac0172000-12-18 21:38:57 +000050 { "b", 512 },
51 { "k", 1024 },
52 { "m", 1048576 },
53 { NULL, 0 }
54};
55
Manuel Novoa III cad53642003-03-19 09:13:01 +000056static int status
57#if EXIT_SUCCESS != 0
58 = EXIT_SUCCESS /* If it is 0 (paranoid check), let bss initialize it. */
59#endif
60 ;
Matt Kraai55bccf32001-01-05 02:57:53 +000061
Manuel Novoa III cad53642003-03-19 09:13:01 +000062static void tail_xprint_header(const char *fmt, const char *filename)
Matt Kraai55bccf32001-01-05 02:57:53 +000063{
Manuel Novoa III cad53642003-03-19 09:13:01 +000064 /* If we get an output error, there is really no sense in continuing. */
65 if (dprintf(STDOUT_FILENO, fmt, filename) < 0) {
66 bb_perror_nomsg_and_die();
67 }
Eric Andersenabc0f4f1999-12-08 23:19:36 +000068}
69
Manuel Novoa III cad53642003-03-19 09:13:01 +000070/* len should probably be size_t */
71static void tail_xbb_full_write(const char *buf, size_t len)
Eric Andersenabc0f4f1999-12-08 23:19:36 +000072{
Manuel Novoa III cad53642003-03-19 09:13:01 +000073 /* If we get a write error, there is really no sense in continuing. */
74 if (bb_full_write(STDOUT_FILENO, buf, len) < 0) {
75 bb_perror_nomsg_and_die();
76 }
Eric Andersenabc0f4f1999-12-08 23:19:36 +000077}
78
Manuel Novoa III cad53642003-03-19 09:13:01 +000079static ssize_t tail_read(int fd, char *buf, size_t count)
80{
81 ssize_t r;
82
83 if ((r = safe_read(fd, buf, count)) < 0) {
84 bb_perror_msg("read");
85 status = EXIT_FAILURE;
86 }
87
88 return r;
89}
90
91static const char tail_opts[] =
92 "fn:"
93#ifdef CONFIG_FEATURE_FANCY_TAIL
94 "c:qs:v"
95#endif
96 ;
97
98static const char header_fmt[] = "\n==> %s <==\n";
99
Eric Andersen98bbd682000-07-31 17:05:58 +0000100int tail_main(int argc, char **argv)
Eric Andersenabc0f4f1999-12-08 23:19:36 +0000101{
Manuel Novoa III cad53642003-03-19 09:13:01 +0000102 long count = 10;
103 unsigned int sleep_period = 1;
104 int from_top = 0;
105 int follow = 0;
106 int header_threshhold = 1;
107#ifdef CONFIG_FEATURE_FANCY_TAIL
108 int count_bytes = 0;
109#endif
Eric Andersenabc0f4f1999-12-08 23:19:36 +0000110
Manuel Novoa III cad53642003-03-19 09:13:01 +0000111 char *tailbuf;
112 size_t tailbufsize;
113 int taillen = 0;
114 int newline = 0;
115
116 int *fds, nfiles, nread, nwrite, seen, i, opt;
117 char *s, *buf;
118 const char *fmt;
119
120 /* Allow legacy syntax of an initial numeric option without -n. */
Eric Andersenb5b5ac32003-03-28 16:54:14 +0000121 if (argc >=2 && ((argv[1][0] == '+') || ((argv[1][0] == '-')
Manuel Novoa III cad53642003-03-19 09:13:01 +0000122 /* && (isdigit)(argv[1][1]) */
Eric Andersenb5b5ac32003-03-28 16:54:14 +0000123 && (((unsigned int)(argv[1][1] - '0')) <= 9))))
124 {
Manuel Novoa III cad53642003-03-19 09:13:01 +0000125 optind = 2;
126 optarg = argv[1];
127 goto GET_COUNT;
Robert Griebl13c26fc2002-05-17 22:18:04 +0000128 }
129
Manuel Novoa III cad53642003-03-19 09:13:01 +0000130 while ((opt = getopt(argc, argv, tail_opts)) > 0) {
Eric Andersend5fa3e32000-08-02 16:42:58 +0000131 switch (opt) {
Matt Kraai55bccf32001-01-05 02:57:53 +0000132 case 'f':
133 follow = 1;
134 break;
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000135#ifdef CONFIG_FEATURE_FANCY_TAIL
Matt Kraai55bccf32001-01-05 02:57:53 +0000136 case 'c':
Manuel Novoa III cad53642003-03-19 09:13:01 +0000137 count_bytes = 1;
Matt Kraai55bccf32001-01-05 02:57:53 +0000138 /* FALLS THROUGH */
Eric Andersen98bbd682000-07-31 17:05:58 +0000139#endif
Matt Kraai55bccf32001-01-05 02:57:53 +0000140 case 'n':
Manuel Novoa III cad53642003-03-19 09:13:01 +0000141 GET_COUNT:
142 count = bb_xgetlarg10_sfx(optarg, tail_suffixes);
143 /* Note: Leading whitespace is an error trapped above. */
144 if (*optarg == '+') {
Matt Kraai55bccf32001-01-05 02:57:53 +0000145 from_top = 1;
Manuel Novoa III cad53642003-03-19 09:13:01 +0000146 } else {
147 from_top = 0;
148 }
149 if (count < 0) {
150 count = -count;
151 }
Eric Andersend5fa3e32000-08-02 16:42:58 +0000152 break;
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000153#ifdef CONFIG_FEATURE_FANCY_TAIL
Matt Kraai55bccf32001-01-05 02:57:53 +0000154 case 'q':
Manuel Novoa III cad53642003-03-19 09:13:01 +0000155 header_threshhold = INT_MAX;
Eric Andersend5fa3e32000-08-02 16:42:58 +0000156 break;
Matt Kraai55bccf32001-01-05 02:57:53 +0000157 case 's':
Manuel Novoa III cad53642003-03-19 09:13:01 +0000158 sleep_period =bb_xgetularg10_bnd(optarg, 0, UINT_MAX);
Matt Kraai55bccf32001-01-05 02:57:53 +0000159 break;
160 case 'v':
Manuel Novoa III cad53642003-03-19 09:13:01 +0000161 header_threshhold = 0;
Matt Kraai55bccf32001-01-05 02:57:53 +0000162 break;
163#endif
164 default:
Manuel Novoa III cad53642003-03-19 09:13:01 +0000165 bb_show_usage();
Eric Andersend5fa3e32000-08-02 16:42:58 +0000166 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000167 }
Matt Kraai55bccf32001-01-05 02:57:53 +0000168
169 /* open all the files */
170 fds = (int *)xmalloc(sizeof(int) * (argc - optind + 1));
Manuel Novoa III cad53642003-03-19 09:13:01 +0000171
172 argv += optind;
173 nfiles = i = 0;
174
175 if ((argc -= optind) == 0) {
176 struct stat statbuf;
177
178 if (!fstat(STDIN_FILENO, &statbuf) && S_ISFIFO(statbuf.st_mode)) {
179 follow = 0;
Matt Kraai55bccf32001-01-05 02:57:53 +0000180 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000181 /* --argv; */
182 *argv = (char *) bb_msg_standard_input;
183 goto DO_STDIN;
Matt Kraai55bccf32001-01-05 02:57:53 +0000184 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000185
186 do {
187 if ((argv[i][0] == '-') && !argv[i][1]) {
188 DO_STDIN:
189 fds[nfiles] = STDIN_FILENO;
190 } else if ((fds[nfiles] = open(argv[i], O_RDONLY)) < 0) {
191 bb_perror_msg("%s", argv[i]);
192 status = EXIT_FAILURE;
193 continue;
194 }
195 argv[nfiles] = argv[i];
196 ++nfiles;
197 } while (++i < argc);
198
199 if (!nfiles) {
200 bb_error_msg_and_die("no files");
201 }
202
203 tailbufsize = BUFSIZ;
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000204#ifdef CONFIG_FEATURE_FANCY_TAIL
Matt Kraai55bccf32001-01-05 02:57:53 +0000205 /* tail the files */
Manuel Novoa III cad53642003-03-19 09:13:01 +0000206 if (from_top < count_bytes) { /* Each is 0 or 1, so true iff 0 < 1. */
207 /* Hence, !from_top && count_bytes */
208 if (tailbufsize < count) {
209 tailbufsize = count + BUFSIZ;
210 }
211 }
Matt Kraai55bccf32001-01-05 02:57:53 +0000212#endif
Manuel Novoa III cad53642003-03-19 09:13:01 +0000213 buf = tailbuf = xmalloc(tailbufsize);
Matt Kraai55bccf32001-01-05 02:57:53 +0000214
Manuel Novoa III cad53642003-03-19 09:13:01 +0000215 fmt = header_fmt + 1; /* Skip header leading newline on first output. */
216 i = 0;
217 do {
218 /* Be careful. It would be possible to optimize the count-bytes
219 * case if the file is seekable. If you do though, remember that
220 * starting file position may not be the beginning of the file.
221 * Beware of backing up too far. See example in wc.c.
222 */
223 if ((!(count|from_top)) && (lseek(fds[i], 0, SEEK_END) >= 0)) {
Eric Andersence98c192001-06-26 15:07:08 +0000224 continue;
225 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000226
227 if (nfiles > header_threshhold) {
228 tail_xprint_header(fmt, argv[i]);
229 fmt = header_fmt;
230 }
231
232 buf = tailbuf;
233 taillen = 0;
234 seen = 1;
235
236 while ((nread = tail_read(fds[i], buf, tailbufsize-taillen)) > 0) {
Matt Kraai55bccf32001-01-05 02:57:53 +0000237 if (from_top) {
Manuel Novoa III cad53642003-03-19 09:13:01 +0000238 nwrite = nread;
239 if (seen < count) {
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000240#ifdef CONFIG_FEATURE_FANCY_TAIL
Manuel Novoa III cad53642003-03-19 09:13:01 +0000241 if (count_bytes) {
242 nwrite -= (count - seen);
243 seen = count;
244 } else
Matt Kraai55bccf32001-01-05 02:57:53 +0000245#endif
Manuel Novoa III cad53642003-03-19 09:13:01 +0000246 {
247 s = buf;
248 do {
249 --nwrite;
250 if ((*s++ == '\n') && (++seen == count)) {
Matt Kraai55bccf32001-01-05 02:57:53 +0000251 break;
252 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000253 } while (nwrite);
254 }
255 }
256 tail_xbb_full_write(buf + nread - nwrite, nwrite);
257 } else if (count) {
258#ifdef CONFIG_FEATURE_FANCY_TAIL
259 if (count_bytes) {
260 taillen += nread;
261 if (taillen > count) {
262 memmove(tailbuf, tailbuf + taillen - count, count);
263 taillen = count;
264 }
265 } else
266#endif
267 {
268 int k = nread;
269 int nbuf = 0;
270
271 while (k) {
272 --k;
273 if (buf[k] == '\n') {
274 ++nbuf;
Matt Kraai55bccf32001-01-05 02:57:53 +0000275 }
276 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000277
278 if (newline + nbuf < count) {
279 newline += nbuf;
280 taillen += nread;
281
Matt Kraai55bccf32001-01-05 02:57:53 +0000282 } else {
Manuel Novoa III cad53642003-03-19 09:13:01 +0000283 int extra = 0;
284 if (buf[nread-1] != '\n') {
285 extra = 1;
286 }
287
288 k = newline + nbuf + extra - count;
289 s = tailbuf;
290 while (k) {
291 if (*s == '\n') {
292 --k;
293 }
294 ++s;
295 }
296
297 taillen += nread - (s - tailbuf);
298 memmove(tailbuf, s, taillen);
299 newline = count - extra;
Matt Kraai55bccf32001-01-05 02:57:53 +0000300 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000301 if (tailbufsize < taillen + BUFSIZ) {
302 tailbufsize = taillen + BUFSIZ;
303 tailbuf = xrealloc(tailbuf, tailbufsize);
Matt Kraai55bccf32001-01-05 02:57:53 +0000304 }
Eric Andersend5fa3e32000-08-02 16:42:58 +0000305 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000306 buf = tailbuf + taillen;
Eric Andersend5fa3e32000-08-02 16:42:58 +0000307 }
308 }
Erik Andersen3fe39dc2000-01-25 18:13:53 +0000309
Manuel Novoa III cad53642003-03-19 09:13:01 +0000310 if (!from_top) {
311 tail_xbb_full_write(tailbuf, taillen);
Matt Kraai55bccf32001-01-05 02:57:53 +0000312 }
313
314 taillen = 0;
Manuel Novoa III cad53642003-03-19 09:13:01 +0000315 } while (++i < nfiles);
316
317 buf = xrealloc(tailbuf, BUFSIZ);
318
319 fmt = NULL;
Matt Kraai55bccf32001-01-05 02:57:53 +0000320
321 while (follow) {
322 sleep(sleep_period);
Manuel Novoa III cad53642003-03-19 09:13:01 +0000323 i = 0;
324 do {
325 if (nfiles > header_threshhold) {
326 fmt = header_fmt;
Matt Kraai55bccf32001-01-05 02:57:53 +0000327 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000328 while ((nread = tail_read(fds[i], buf, sizeof(buf))) > 0) {
329 if (fmt) {
330 tail_xprint_header(fmt, argv[i]);
331 fmt = NULL;
332 }
333 tail_xbb_full_write(buf, nread);
Matt Kraai55bccf32001-01-05 02:57:53 +0000334 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000335 } while (++i < nfiles);
Matt Kraai55bccf32001-01-05 02:57:53 +0000336 }
337
338 return status;
339}