util-linux/dmesg.c

/* vi: set sw=4 ts=4: */
/* 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@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.
 *
 * Audited and cleaned up on 7 March 2003 to reduce size of
 * check error handling by Erik Andersen <andersee@debian.org>
 */

#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <errno.h>

#if __GNU_LIBRARY__ < 5
# ifdef __alpha__
#   define klogctl syslog
# endif
#else
# include <sys/klog.h>
#endif

#include "busybox.h"

int dmesg_main(int argc, char **argv)
{
	char *buf;
	int bufsize = 8196;
	int i, n;
	int level = 0;
	int lastc;
	int cmd = 3;

	while ((i = getopt(argc, argv, "cn:s:")) > 0) {
		switch (i) {
			case 'c':
				cmd = 4;
				break;
			case 'n':
				cmd = 8;
				level = bb_xgetlarg(optarg, 10, 0, 10);
				break;
			case 's':
				/* I think a 512k max kernel ring buffer is big enough for
				 * anybody, as the default is 16k...  Could be wrong though.
				 * If so I'm sure I'll hear about it by the enraged masses*/
				bufsize = bb_xgetlarg(optarg, 10, 4096, 512*1024);
				break;
			default:
				bb_show_usage();
		}
	}

	if (optind < argc) {
		bb_show_usage();
	}

	if (cmd == 8) {
		if (klogctl(cmd, NULL, level) < 0)
			goto die_the_death;
		goto all_done;
	}

	buf = xmalloc(bufsize);
	if ((n = klogctl(cmd, buf, bufsize)) < 0)
		goto die_the_death;

	lastc = '\n';
	for (i = 0; i < n; i++) {
		if (lastc == '\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');
all_done:
#ifdef CONFIG_FEATURE_CLEAN_UP
	if (buf) {
		free(buf);
	}
#endif
	return EXIT_SUCCESS;
die_the_death:
	bb_perror_nomsg_and_die();
}