busybox/sysklogd/klogd.c

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/* vi: set sw=4 ts=4: */
/*
* Mini klogd implementation for busybox
*
* Copyright (C) 2001 by Gennady Feldman <gfeldman@gena01.com>.
* Changes: Made this a standalone busybox module which uses standalone
* syslog() client interface.
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
*
* Copyright (C) 2000 by Karl M. Hegbloom <karlheg@debian.org>
*
* "circular buffer" Copyright (C) 2000 by Gennady Feldman <gfeldman@gena01.com>
*
* Maintainer: Gennady Feldman <gfeldman@gena01.com> as of Mar 12, 2001
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <stdio.h>
#include <stdlib.h>
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#include <signal.h> /* for our signal() handlers */
#include <string.h> /* strncpy() */
#include <errno.h> /* errno and friends */
#include <unistd.h>
#include <ctype.h>
#include <sys/syslog.h>
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#include <sys/klog.h>
#include "busybox.h"
static void klogd_signal(int sig)
{
klogctl(7, NULL, 0);
klogctl(0, 0, 0);
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/* logMessage(0, "Kernel log daemon exiting."); */
syslog(LOG_NOTICE, "Kernel log daemon exiting.");
exit(EXIT_SUCCESS);
}
static void doKlogd(const int console_log_level) __attribute__ ((noreturn));
static void doKlogd(const int console_log_level)
{
int priority = LOG_INFO;
char log_buffer[4096];
int i, n, lastc;
char *start;
openlog("kernel", 0, LOG_KERN);
/* Set up sig handlers */
signal(SIGINT, klogd_signal);
signal(SIGKILL, klogd_signal);
signal(SIGTERM, klogd_signal);
signal(SIGHUP, SIG_IGN);
/* "Open the log. Currently a NOP." */
klogctl(1, NULL, 0);
/* Set level of kernel console messaging.. */
if (console_log_level != -1)
klogctl(8, NULL, console_log_level);
syslog(LOG_NOTICE, "klogd started: " BB_BANNER);
while (1) {
/* Use kernel syscalls */
memset(log_buffer, '\0', sizeof(log_buffer));
n = klogctl(2, log_buffer, sizeof(log_buffer));
if (n < 0) {
if (errno == EINTR)
continue;
syslog(LOG_ERR, "klogd: Error return from sys_sycall: %d - %m.\n", errno);
exit(EXIT_FAILURE);
}
/* klogctl buffer parsing modelled after code in dmesg.c */
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start = &log_buffer[0];
lastc = '\0';
for (i = 0; i < n; i++) {
if (lastc == '\0' && log_buffer[i] == '<') {
priority = 0;
i++;
while (isdigit(log_buffer[i])) {
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priority = priority * 10 + (log_buffer[i] - '0');
i++;
}
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if (log_buffer[i] == '>')
i++;
start = &log_buffer[i];
}
if (log_buffer[i] == '\n') {
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log_buffer[i] = '\0'; /* zero terminate this message */
syslog(priority, "%s", start);
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start = &log_buffer[i + 1];
priority = LOG_INFO;
}
lastc = log_buffer[i];
}
}
}
extern int klogd_main(int argc, char **argv)
{
/* no options, no getopt */
int opt;
int doFork = TRUE;
unsigned char console_log_level = -1;
/* do normal option parsing */
while ((opt = getopt(argc, argv, "c:n")) > 0) {
switch (opt) {
case 'c':
if ((optarg == NULL) || (optarg[1] != '\0')) {
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bb_show_usage();
}
/* Valid levels are between 1 and 8 */
console_log_level = *optarg - '1';
if (console_log_level > 7) {
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bb_show_usage();
}
console_log_level++;
break;
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case 'n':
doFork = FALSE;
break;
default:
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bb_show_usage();
}
}
if (doFork) {
#if defined(__uClinux__)
vfork_daemon_rexec(0, 1, argc, argv, "-n");
#else /* __uClinux__ */
if (daemon(0, 1) < 0)
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bb_perror_msg_and_die("daemon");
#endif /* __uClinux__ */
}
doKlogd(console_log_level);
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return EXIT_SUCCESS;
}
/*
Local Variables
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/