aboutsummaryrefslogtreecommitdiff
path: root/tail.c
diff options
context:
space:
mode:
Diffstat (limited to 'tail.c')
-rw-r--r--tail.c251
1 files changed, 0 insertions, 251 deletions
diff --git a/tail.c b/tail.c
deleted file mode 100644
index 5e5fbc14f..000000000
--- a/tail.c
+++ /dev/null
@@ -1,251 +0,0 @@
1/* vi: set sw=4 ts=4: */
2/*
3 * Mini tail implementation for busybox
4 *
5 *
6 * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 *
22 */
23
24
25#include <fcntl.h>
26#include <getopt.h>
27#include <string.h>
28#include <stdlib.h>
29#include <unistd.h>
30#include <sys/types.h>
31#include "busybox.h"
32
33static const struct suffix_mult tail_suffixes[] = {
34 { "b", 512 },
35 { "k", 1024 },
36 { "m", 1048576 },
37 { NULL, 0 }
38};
39
40static const int BYTES = 0;
41static const int LINES = 1;
42
43static char *tailbuf;
44static int taillen;
45static int newline;
46
47static void tailbuf_append(char *buf, int len)
48{
49 tailbuf = xrealloc(tailbuf, taillen + len);
50 memcpy(tailbuf + taillen, buf, len);
51 taillen += len;
52}
53
54static void tailbuf_trunc(void)
55{
56 char *s;
57 s = memchr(tailbuf, '\n', taillen);
58 memmove(tailbuf, s + 1, taillen - ((s + 1) - tailbuf));
59 taillen -= (s + 1) - tailbuf;
60 newline = 0;
61}
62
63int tail_main(int argc, char **argv)
64{
65 int from_top = 0, units = LINES, count = 10, sleep_period = 1;
66 int show_headers = 0, hide_headers = 0, follow = 0;
67 int *fds, nfiles = 0, status = EXIT_SUCCESS, nread, nwrite, seen = 0;
68 char *s, *start, *end, buf[BUFSIZ];
69 int i, opt;
70
71 while ((opt = getopt(argc, argv, "c:fhn:q:s:v")) > 0) {
72 switch (opt) {
73 case 'f':
74 follow = 1;
75 break;
76#ifdef BB_FEATURE_FANCY_TAIL
77 case 'c':
78 units = BYTES;
79 /* FALLS THROUGH */
80#endif
81 case 'n':
82 count = parse_number(optarg, tail_suffixes);
83 if (count < 0)
84 count = -count;
85 if (optarg[0] == '+')
86 from_top = 1;
87 break;
88#ifdef BB_FEATURE_FANCY_TAIL
89 case 'q':
90 hide_headers = 1;
91 break;
92 case 's':
93 sleep_period = parse_number(optarg, 0);
94 break;
95 case 'v':
96 show_headers = 1;
97 break;
98#endif
99 default:
100 show_usage();
101 }
102 }
103
104 /* open all the files */
105 fds = (int *)xmalloc(sizeof(int) * (argc - optind + 1));
106 if (argc == optind) {
107 fds[nfiles++] = STDIN_FILENO;
108 argv[optind] = "standard input";
109 } else {
110 for (i = optind; i < argc; i++) {
111 if (strcmp(argv[i], "-") == 0) {
112 fds[nfiles++] = STDIN_FILENO;
113 argv[i] = "standard input";
114 } else if ((fds[nfiles++] = open(argv[i], O_RDONLY)) < 0) {
115 perror_msg("%s", argv[i]);
116 status = EXIT_FAILURE;
117 }
118 }
119 }
120
121#ifdef BB_FEATURE_FANCY_TAIL
122 /* tail the files */
123 if (!from_top && units == BYTES)
124 tailbuf = xmalloc(count);
125#endif
126
127 for (i = 0; i < nfiles; i++) {
128 if (fds[i] == -1)
129 continue;
130 if (!count) {
131 lseek(fds[i], 0, SEEK_END);
132 continue;
133 }
134 seen = 0;
135 if (show_headers || (!hide_headers && nfiles > 1))
136 printf("%s==> %s <==\n", i == 0 ? "" : "\n", argv[optind + i]);
137 while ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0) {
138 if (from_top) {
139#ifdef BB_FEATURE_FANCY_TAIL
140 if (units == BYTES) {
141 if (count - 1 <= seen)
142 nwrite = nread;
143 else if (count - 1 <= seen + nread)
144 nwrite = nread + seen - (count - 1);
145 else
146 nwrite = 0;
147 seen += nread;
148 } else {
149#else
150 {
151#endif
152 if (count - 1 <= seen)
153 nwrite = nread;
154 else {
155 nwrite = 0;
156 for (s = memchr(buf, '\n', nread); s != NULL;
157 s = memchr(s+1, '\n', nread - (s + 1 - buf))) {
158 if (count - 1 <= ++seen) {
159 nwrite = nread - (s + 1 - buf);
160 break;
161 }
162 }
163 }
164 }
165 if (full_write(STDOUT_FILENO, buf + nread - nwrite,
166 nwrite) < 0) {
167 perror_msg("write");
168 status = EXIT_FAILURE;
169 break;
170 }
171 } else {
172#ifdef BB_FEATURE_FANCY_TAIL
173 if (units == BYTES) {
174 if (nread < count) {
175 memmove(tailbuf, tailbuf + nread, count - nread);
176 memcpy(tailbuf + count - nread, buf, nread);
177 } else {
178 memcpy(tailbuf, buf + nread - count, count);
179 }
180 seen += nread;
181 } else {
182#else
183 {
184#endif
185 for (start = buf, end = memchr(buf, '\n', nread);
186 end != NULL; start = end+1,
187 end = memchr(start, '\n', nread - (start - buf))) {
188 if (newline && count <= seen)
189 tailbuf_trunc();
190 tailbuf_append(start, end - start + 1);
191 seen++;
192 newline = 1;
193 }
194 if (newline && count <= seen && nread - (start - buf) > 0)
195 tailbuf_trunc();
196 tailbuf_append(start, nread - (start - buf));
197 }
198 }
199 }
200
201 if (nread < 0) {
202 perror_msg("read");
203 status = EXIT_FAILURE;
204 }
205
206#ifdef BB_FEATURE_FANCY_TAIL
207 if (!from_top && units == BYTES) {
208 if (count < seen)
209 seen = count;
210 if (full_write(STDOUT_FILENO, tailbuf + count - seen, seen) < 0) {
211 perror_msg("write");
212 status = EXIT_FAILURE;
213 }
214 }
215#endif
216
217 if (!from_top && units == LINES) {
218 if (full_write(STDOUT_FILENO, tailbuf, taillen) < 0) {
219 perror_msg("write");
220 status = EXIT_FAILURE;
221 }
222 }
223
224 taillen = 0;
225 }
226
227 while (follow) {
228 sleep(sleep_period);
229
230 for (i = 0; i < nfiles; i++) {
231 if (fds[i] == -1)
232 continue;
233
234 if ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0) {
235 if (show_headers || (!hide_headers && nfiles > 1))
236 printf("\n==> %s <==\n", argv[optind + i]);
237
238 do {
239 full_write(STDOUT_FILENO, buf, nread);
240 } while ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0);
241 }
242
243 if (nread < 0) {
244 perror_msg("read");
245 status = EXIT_FAILURE;
246 }
247 }
248 }
249
250 return status;
251}
generated by cgit v1.2.3-55-g6feb (git 2.39.1) at 2025-03-24 00:54:22 +0000