busybox/util-linux/dmesg.c
Denys Vlasenko f560422fa0 Big cleanup in config help and description
Redundant help texts (one which only repeats the description)
are deleted.

Descriptions and help texts are trimmed.

Some config options are moved, even across menus.

No config option _names_ are changed.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-01-10 14:58:54 +01:00

125 lines
3.5 KiB
C

/* vi: set sw=4 ts=4: */
/*
*
* 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.
*/
//config:config DMESG
//config: bool "dmesg"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: dmesg is used to examine or control the kernel ring buffer. When the
//config: Linux kernel prints messages to the system log, they are stored in
//config: the kernel ring buffer. You can use dmesg to print the kernel's ring
//config: buffer, clear the kernel ring buffer, change the size of the kernel
//config: ring buffer, and change the priority level at which kernel messages
//config: are also logged to the system console. Enable this option if you
//config: wish to enable the 'dmesg' utility.
//config:
//config:config FEATURE_DMESG_PRETTY
//config: bool "Pretty output"
//config: default y
//config: depends on DMESG
//config: help
//config: If you wish to scrub the syslog level from the output, say 'Y' here.
//config: The syslog level is a string prefixed to every line with the form
//config: "<#>".
//config:
//config: With this option you will see:
//config: # dmesg
//config: Linux version 2.6.17.4 .....
//config: BIOS-provided physical RAM map:
//config: BIOS-e820: 0000000000000000 - 000000000009f000 (usable)
//config:
//config: Without this option you will see:
//config: # dmesg
//config: <5>Linux version 2.6.17.4 .....
//config: <6>BIOS-provided physical RAM map:
//config: <6> BIOS-e820: 0000000000000000 - 000000000009f000 (usable)
//applet:IF_DMESG(APPLET(dmesg, BB_DIR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_DMESG) += dmesg.o
//usage:#define dmesg_trivial_usage
//usage: "[-c] [-n LEVEL] [-s SIZE]"
//usage:#define dmesg_full_usage "\n\n"
//usage: "Print or control the kernel ring buffer\n"
//usage: "\n -c Clear ring buffer after printing"
//usage: "\n -n LEVEL Set console logging level"
//usage: "\n -s SIZE Buffer size"
//usage: "\n -r Print raw message buffer"
#include <sys/klog.h>
#include "libbb.h"
int dmesg_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int dmesg_main(int argc UNUSED_PARAM, char **argv)
{
int len, level;
char *buf;
unsigned opts;
enum {
OPT_c = 1 << 0,
OPT_s = 1 << 1,
OPT_n = 1 << 2,
OPT_r = 1 << 3
};
opts = getopt32(argv, "cs:+n:+r", &len, &level);
if (opts & OPT_n) {
if (klogctl(8, NULL, (long) level))
bb_perror_msg_and_die("klogctl");
return EXIT_SUCCESS;
}
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 (ENABLE_FEATURE_DMESG_PRETTY && !(opts & OPT_r)) {
int last = '\n';
int in = 0;
/* Skip <[0-9]+> at the start of lines */
while (1) {
if (last == '\n' && buf[in] == '<') {
while (buf[in++] != '>' && in < len)
;
} else {
last = buf[in++];
putchar(last);
}
if (in >= len)
break;
}
/* Make sure we end with a newline */
if (last != '\n')
bb_putchar('\n');
} else {
full_write(STDOUT_FILENO, buf, len);
if (buf[len-1] != '\n')
bb_putchar('\n');
}
if (ENABLE_FEATURE_CLEAN_UP) free(buf);
return EXIT_SUCCESS;
}