busybox/dmesg.c

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/* vi: set sw=4 ts=4: */
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/* 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<EFBFBD>kiewicz <misiek@misiek.eu.org>
* - added Native Language Support
*
* from util-linux -- adapted for busybox by
* Erik Andersen <andersee@debian.org>. I ripped out Native Language
* Support, replaced getopt, added some gotos for redundant stuff.
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*/
#include "internal.h"
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#include <linux/unistd.h>
#include <stdio.h>
#include <getopt.h>
#include <stdlib.h>
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#if __GNU_LIBRARY__ < 5
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#ifndef __alpha__
# define __NR_klogctl __NR_syslog
static inline _syscall3(int, klogctl, int, type, char *, b, int, len);
#else /* __alpha__ */
#define klogctl syslog
#endif
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#else
# include <sys/klog.h>
#endif
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static const char dmesg_usage[] = "dmesg [-c] [-n LEVEL] [-s SIZE]\n"
#ifndef BB_FEATURE_TRIVIAL_HELP
"\nPrints or controls the kernel ring buffer\n\n"
"Options:\n"
"\t-c\t\tClears the ring buffer's contents after printing\n"
"\t-n LEVEL\tSets console logging level\n"
"\t-s SIZE\t\tUse a buffer of size SIZE\n"
#endif
;
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int dmesg_main(int argc, char **argv)
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{
char *buf;
int bufsize = 8196;
int i;
int n;
int level = 0;
int lastc;
int cmd = 3;
int stopDoingThat;
argc--;
argv++;
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/* Parse any options */
while (argc && **argv == '-') {
stopDoingThat = FALSE;
while (stopDoingThat == FALSE && *++(*argv)) {
switch (**argv) {
case 'c':
cmd = 4;
break;
case 'n':
cmd = 8;
if (--argc == 0)
goto end;
level = atoi(*(++argv));
if (--argc > 0)
++argv;
stopDoingThat = TRUE;
break;
case 's':
if (--argc == 0)
goto end;
bufsize = atoi(*(++argv));
if (--argc > 0)
++argv;
stopDoingThat = TRUE;
break;
default:
goto end;
}
}
}
if (argc > 1) {
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goto end;
}
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if (cmd == 8) {
n = klogctl(cmd, NULL, level);
if (n < 0) {
goto klogctl_error;
}
exit(TRUE);
}
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if (bufsize < 4096)
bufsize = 4096;
buf = (char *) xmalloc(bufsize);
n = klogctl(cmd, buf, bufsize);
if (n < 0) {
goto klogctl_error;
}
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lastc = '\n';
for (i = 0; i < n; i++) {
if ((i == 0 || buf[i - 1] == '\n') && buf[i] == '<') {
i++;
while (buf[i] >= '0' && buf[i] <= '9')
i++;
if (buf[i] == '>')
i++;
}
lastc = buf[i];
putchar(lastc);
}
if (lastc != '\n')
putchar('\n');
exit(TRUE);
end:
usage(dmesg_usage);
exit(FALSE);
klogctl_error:
perror("klogctl");
exit(FALSE);
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}