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/*
* sensord
*
* A daemon that periodically logs sensor information to syslog.
*
* Copyright (c) 1999-2002 Merlin Hughes <merlin@merlin.org>
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <limits.h>
#include <string.h>
#include <signal.h>
#include <syslog.h>
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "sensord.h"
static int logOpened = 0;
static volatile sig_atomic_t done = 0;
#define LOG_BUFFER 4096
#include <stdarg.h>
void
sensorLog
(int priority, const char *fmt, ...) {
static char buffer[1 + LOG_BUFFER];
va_list ap;
va_start (ap, fmt);
vsnprintf (buffer, LOG_BUFFER, fmt, ap);
buffer[LOG_BUFFER] = '\0';
va_end (ap);
if (debug || (priority < LOG_DEBUG)) {
if (logOpened) {
syslog (priority, "%s", buffer);
} else {
fprintf (stderr, "%s\n", buffer);
fflush (stderr);
}
}
}
static void
signalHandler
(int sig) {
signal (sig, signalHandler);
switch (sig) {
case SIGTERM:
done = 1;
break;
}
}
static int
sensord
(void) {
int ret = 0;
int scanValue = 0, logValue = 0;
/*
* First RRD update at next RRD timeslot to prevent failures due
* one timeslot updated twice on restart for example.
*/
int rrdValue = rrdTime - time(NULL) % rrdTime;
sensorLog (LOG_INFO, "sensord started");
while (!done && (ret == 0)) {
if (ret == 0)
ret = reloadLib ();
if ((ret == 0) && scanTime) { /* should I scan on the read cycle? */
ret = scanChips ();
if (scanValue <= 0)
scanValue += scanTime;
}
if ((ret == 0) && logTime && (logValue <= 0)) {
ret = readChips ();
logValue += logTime;
}
if ((ret == 0) && rrdTime && rrdFile && (rrdValue <= 0)) {
ret = rrdUpdate ();
/*
* The amount of time to wait is computed using the same method as
* in RRD instead of simply adding the interval.
*/
rrdValue = rrdTime - time(NULL) % rrdTime;
}
if (!done && (ret == 0)) {
int a = logTime ? logValue : INT_MAX;
int b = scanTime ? scanValue : INT_MAX;
int c = (rrdTime && rrdFile) ? rrdValue : INT_MAX;
int sleepTime = (a < b) ? ((a < c) ? a : c) : ((b < c) ? b : c);
sleep (sleepTime);
scanValue -= sleepTime;
logValue -= sleepTime;
rrdValue -= sleepTime;
}
}
if (ret)
sensorLog (LOG_INFO, "sensord failed (%d)", ret);
else
sensorLog (LOG_INFO, "sensord stopped");
return ret;
}
static void
openLog
(void) {
openlog ("sensord", 0, syslogFacility);
logOpened = 1;
}
static void
daemonize
(void) {
int pid;
struct stat fileStat;
FILE *file;
if (chdir ("/") < 0) {
perror ("chdir()");
exit (EXIT_FAILURE);
}
if (!(stat (pidFile, &fileStat)) &&
((!S_ISREG (fileStat.st_mode)) || (fileStat.st_size > 11))) {
fprintf (stderr, "Error: PID file `%s' already exists and looks suspicious.\n", pidFile);
exit (EXIT_FAILURE);
}
if (!(file = fopen (pidFile, "w"))) {
fprintf (stderr, "fopen(\"%s\"): %s\n", pidFile, strerror (errno));
exit (EXIT_FAILURE);
}
/* I should use sigaction but... */
if (signal (SIGTERM, signalHandler) == SIG_ERR) {
perror ("signal(SIGTERM)");
exit (EXIT_FAILURE);
}
if ((pid = fork ()) == -1) {
perror ("fork()");
exit (EXIT_FAILURE);
} else if (pid != 0) {
fprintf (file, "%d\n", pid);
fclose (file);
unloadLib ();
exit (EXIT_SUCCESS);
}
if (setsid () < 0) {
perror ("setsid()");
exit (EXIT_FAILURE);
}
fclose (file);
close (STDIN_FILENO);
close (STDOUT_FILENO);
close (STDERR_FILENO);
}
static void
undaemonize
(void) {
unlink (pidFile);
closelog ();
}
int
main
(int argc, char **argv) {
int ret = 0;
if (parseArgs (argc, argv) ||
parseChips (argc, argv))
exit (EXIT_FAILURE);
if (initLib () ||
loadLib ())
exit (EXIT_FAILURE);
if (isDaemon)
openLog ();
if (rrdFile)
ret = rrdInit ();
if (ret) {
} else if (doCGI) {
ret = rrdCGI ();
} else if (isDaemon) {
daemonize ();
ret = sensord ();
undaemonize ();
} else {
if (doSet)
ret = setChips ();
else if (doScan)
ret = scanChips ();
else if (rrdFile)
ret = rrdUpdate ();
else
ret = readChips ();
}
if (unloadLib ())
exit (EXIT_FAILURE);
return ret;
}
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