1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
/* dmesg.c -- Print out the contents of the kernel ring buffer
* Created: Sat Oct 9 16:19:47 1993
* Revised: Thu Oct 28 21:52:17 1993 by faith@cs.unc.edu
* Copyright 1993 Theodore Ts'o (tytso@athena.mit.edu)
* This program comes with ABSOLUTELY NO WARRANTY.
* Modifications by Rick Sladkey (jrs@world.std.com)
* Larger buffersize 3 June 1998 by Nicolai Langfeldt, based on a patch
* by Peeter Joot. This was also suggested by John Hudson.
* 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@pld.ORG.PL>
* - added Native Language Support
*
*/
#include <linux/unistd.h>
#include <stdio.h>
#include <getopt.h>
#include <stdlib.h>
#include <sys/klog.h>
#include <ctype.h>
#include "c.h"
#include "nls.h"
#include "strutils.h"
#include "xalloc.h"
/* Close the log. Currently a NOP. */
#define SYSLOG_ACTION_CLOSE 0
/* Open the log. Currently a NOP. */
#define SYSLOG_ACTION_OPEN 1
/* Read from the log. */
#define SYSLOG_ACTION_READ 2
/* Read all messages remaining in the ring buffer. (allowed for non-root) */
#define SYSLOG_ACTION_READ_ALL 3
/* Read and clear all messages remaining in the ring buffer */
#define SYSLOG_ACTION_READ_CLEAR 4
/* Clear ring buffer. */
#define SYSLOG_ACTION_CLEAR 5
/* Disable printk's to console */
#define SYSLOG_ACTION_CONSOLE_OFF 6
/* Enable printk's to console */
#define SYSLOG_ACTION_CONSOLE_ON 7
/* Set level of messages printed to console */
#define SYSLOG_ACTION_CONSOLE_LEVEL 8
/* Return number of unread characters in the log buffer */
#define SYSLOG_ACTION_SIZE_UNREAD 9
/* Return size of the log buffer */
#define SYSLOG_ACTION_SIZE_BUFFER 10
/* dmesg flags */
#define DMESG_FL_RAW (1 << 1)
static void __attribute__((__noreturn__)) usage(FILE *out)
{
fprintf(out, _(
"\nUsage:\n"
" %s [options]\n"), program_invocation_short_name);
fprintf(out, _(
"\nOptions:\n"
" -c, --read-clear read and clear all messages\n"
" -r, --raw print the raw message buffer\n"
" -s, --buffer-size=SIZE buffer size to query the kernel ring buffer\n"
" -n, --console-level=LEVEL set level of messages printed to console\n"
" -V, --version output version information and exit\n"
" -h, --help display this help and exit\n\n"));
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
static int get_buffer_size()
{
int n = klogctl(SYSLOG_ACTION_SIZE_BUFFER, NULL, 0);
return n > 0 ? n : 0;
}
static int read_buffer(char **buf, size_t bufsize, int clear)
{
size_t sz;
int rc = -1;
int cmd = clear ? SYSLOG_ACTION_READ_CLEAR :
SYSLOG_ACTION_READ_ALL;
if (bufsize) {
sz = bufsize + 8;
*buf = xmalloc(sz * sizeof(char));
rc = klogctl(cmd, *buf, sz);
} else {
sz = 16392;
while (1) {
*buf = xmalloc(sz * sizeof(char));
rc = klogctl(SYSLOG_ACTION_READ_ALL, *buf, sz);
if (rc != sz || sz > (1 << 28))
break;
free(*buf);
*buf = NULL;
sz *= 4;
}
if (rc > 0 && clear)
rc = klogctl(SYSLOG_ACTION_READ_CLEAR, *buf, sz);
}
return rc;
}
static void print_buffer(const char *buf, size_t size, int flags)
{
int lastc = '\n';
int i;
for (i = 0; i < size; i++) {
if (!(flags & DMESG_FL_RAW) &&
(i == 0 || buf[i - 1] == '\n') && buf[i] == '<') {
i++;
while (isdigit(buf[i]))
i++;
if (buf[i] == '>')
i++;
}
lastc = buf[i];
putchar(lastc);
}
if (lastc != '\n')
putchar('\n');
}
int main(int argc, char *argv[])
{
char *buf = NULL;
int bufsize = 0;
int n;
int c;
int level = 0;
int cmd = SYSLOG_ACTION_READ_ALL;
int flags = 0;
static const struct option longopts[] = {
{ "read-clear", no_argument, NULL, 'c' },
{ "raw", no_argument, NULL, 'r' },
{ "buffer-size", required_argument, NULL, 's' },
{ "console-level", required_argument, NULL, 'n' },
{ "version", no_argument, NULL, 'V' },
{ "help", no_argument, NULL, 'h' },
{ NULL, 0, NULL, 0 }
};
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
while ((c = getopt_long(argc, argv, "chrn:s:V", longopts, NULL)) != -1) {
switch (c) {
case 'c':
cmd = SYSLOG_ACTION_READ_CLEAR;
break;
case 'n':
cmd = SYSLOG_ACTION_CONSOLE_LEVEL;
level = strtol_or_err(optarg, _("failed to parse level"));
break;
case 'r':
flags |= DMESG_FL_RAW;
break;
case 's':
bufsize = strtol_or_err(optarg, _("failed to parse buffer size"));
if (bufsize < 4096)
bufsize = 4096;
break;
case 'V':
printf(_("%s from %s\n"), program_invocation_short_name,
PACKAGE_STRING);
return EXIT_SUCCESS;
case 'h':
usage(stdout);
break;
case '?':
default:
usage(stderr);
}
}
argc -= optind;
argv += optind;
if (argc > 1)
usage(stderr);
if (cmd == SYSLOG_ACTION_CONSOLE_LEVEL) {
n = klogctl(cmd, NULL, level);
if (n < 0)
err(EXIT_FAILURE, _("klogctl failed"));
return EXIT_SUCCESS;
}
if (!bufsize)
bufsize = get_buffer_size();
n = read_buffer(&buf, bufsize, cmd == SYSLOG_ACTION_READ_CLEAR);
if (n < 0)
err(EXIT_FAILURE, _("klogctl failed"));
print_buffer(buf, n, flags);
free(buf);
return EXIT_SUCCESS;
}
|
