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/* dmesg.c - display/control kernel ring buffer.
*
* Copyright 2006, 2007 Rob Landley <rob@landley.net>
*
* http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/dmesg.html
// We care that FLAG_c is 1, so keep c at the end.
USE_DMESG(NEWTOY(dmesg, "trs#<1n#c[!tr]", TOYFLAG_BIN))
config DMESG
bool "dmesg"
default y
help
usage: dmesg [-c] [-r|-t] [-n LEVEL] [-s SIZE]
Print or control the kernel ring buffer.
-c Clear the ring buffer after printing
-n Set kernel logging LEVEL (1-9)
-r Raw output (with <level markers>)
-s Show the last SIZE many bytes
-t Don't print kernel's timestamps
*/
#define FOR_dmesg
#include "toys.h"
#include <sys/klog.h>
GLOBALS(
long level;
long size;
)
void dmesg_main(void)
{
// For -n just tell kernel to which messages to keep.
if (toys.optflags & FLAG_n) {
if (klogctl(8, NULL, TT.level)) perror_exit("klogctl");
} else {
char *data, *to, *from;
int size;
// Figure out how much data we need, and fetch it.
size = TT.size;
if (!size && 1>(size = klogctl(10, 0, 0))) perror_exit("klogctl");;
data = to = from = xmalloc(size+1);
size = klogctl(3 + (toys.optflags & FLAG_c), data, size);
if (size < 0) perror_exit("klogctl");
data[size] = 0;
// Filter out level markers and optionally time markers
if (!(toys.optflags & FLAG_r)) while ((from - data) < size) {
if (from == data || from[-1] == '\n') {
char *to;
if (*from == '<' && (to = strchr(from, '>'))) from = ++to;
if ((toys.optflags&FLAG_t) && *from == '[' && (to = strchr(from, ']')))
from = to+1+(to[1]==' ');
}
*(to++) = *(from++);
} else to = data+size;
// Write result. The odds of somebody requesting a buffer of size 3 and
// getting "<1>" are remote, but don't segfault if they do.
if (to != data) {
xwrite(1, data, to-data);
if (to[-1] != '\n') xputc('\n');
}
if (CFG_TOYBOX_FREE) free(data);
}
}
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