/* 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.
+ * dmesg - display/control kernel ring buffer.
+ *
+ * Copyright 2006 Rob Landley <rob@landley.net>
+ * Copyright 2006 Bernhard Reutner-Fischer <rep.nop@aon.at>
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
*/
+#include <sys/klog.h>
+#include "libbb.h"
-#include "busybox.h"
-#include <stdio.h>
-#include <stdlib.h>
-#include <getopt.h>
-
-#if __GNU_LIBRARY__ < 5
-#include <sys/syscall.h>
-#include <linux/unistd.h>
-#ifndef __alpha__
-# define __NR_klogctl __NR_syslog
-static inline _syscall3(int, klogctl, int, type, char *, b, int, len);
-#else /* __alpha__ */
-#define klogctl syslog
-#endif
-
-#else
-# include <sys/klog.h>
-#endif
-
-int dmesg_main(int argc, char **argv)
+int dmesg_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int dmesg_main(int argc UNUSED_PARAM, char **argv)
{
+ int len, level;
char *buf;
- int c;
- int bufsize = 8196;
- int i;
- int n;
- int level = 0;
- int lastc;
- int cmd = 3;
-
- while ((c = getopt(argc, argv, "cn:s:")) != EOF) {
- switch (c) {
- case 'c':
- cmd = 4;
- break;
- case 'n':
- cmd = 8;
- if (optarg == NULL)
- show_usage();
- level = atoi(optarg);
- break;
- case 's':
- if (optarg == NULL)
- show_usage();
- bufsize = atoi(optarg);
- break;
- default:
- show_usage();
- }
- }
+ unsigned opts;
+ enum {
+ OPT_c = 1 << 0,
+ OPT_s = 1 << 1,
+ OPT_n = 1 << 2
+ };
- if (optind < argc) {
- show_usage();
+ opt_complementary = "s+:n+"; /* numeric */
+ opts = getopt32(argv, "cs:n:", &len, &level);
+ if (opts & OPT_n) {
+ if (klogctl(8, NULL, (long) level))
+ bb_perror_msg_and_die("klogctl");
+ return EXIT_SUCCESS;
}
- if (cmd == 8) {
- if (klogctl(cmd, NULL, level) < 0)
- perror_msg_and_die("klogctl");
+ if (!(opts & OPT_s))
+ len = klogctl(10, NULL, 0); /* read ring buffer size */
+ if (len < 16*1024)
+ len = 16*1024;
+ if (len > 16*1024*1024)
+ len = 16*1024*1024;
+
+ buf = xmalloc(len);
+ len = klogctl(3 + (opts & OPT_c), buf, len); /* read ring buffer */
+ if (len < 0)
+ bb_perror_msg_and_die("klogctl");
+ if (len == 0)
return EXIT_SUCCESS;
- }
- if (bufsize < 4096)
- bufsize = 4096;
- buf = (char *) xmalloc(bufsize);
- if ((n = klogctl(cmd, buf, bufsize)) < 0)
- perror_msg_and_die("klogctl");
+ /* Skip <#> at the start of lines, and make sure we end with a newline */
- 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 (ENABLE_FEATURE_DMESG_PRETTY) {
+ int last = '\n';
+ int in = 0;
+
+ do {
+ if (last == '\n' && buf[in] == '<')
+ in += 3;
+ else {
+ last = buf[in++];
+ bb_putchar(last);
+ }
+ } while (in < len);
+ if (last != '\n')
+ bb_putchar('\n');
+ } else {
+ full_write(STDOUT_FILENO, buf, len);
+ if (buf[len-1] != '\n')
+ bb_putchar('\n');
}
- if (lastc != '\n')
- putchar('\n');
+
+ if (ENABLE_FEATURE_CLEAN_UP) free(buf);
+
return EXIT_SUCCESS;
}