#!/usr/bin/perl
##########################################################################
# Pandora FMS Server
# Pandora FMS. the Flexible Monitoring System. http://www.pandorafms.org
##########################################################################
# Copyright (c) 2005-2010 Artica Soluciones Tecnologicas S.L
#
# 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; version 2
# 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
##########################################################################

use strict;
use warnings;
use POSIX qw(strftime);

# Default lib dir for RPM and DEB packages
use lib '/usr/lib/perl5';

# Pandora Modules
use PandoraFMS::DB;
use PandoraFMS::Config;
use PandoraFMS::Tools;
use PandoraFMS::Core;
use PandoraFMS::DataServer;
use PandoraFMS::NetworkServer;
use PandoraFMS::SNMPServer;
use PandoraFMS::ReconServer;
use PandoraFMS::WMIServer;
use PandoraFMS::PluginServer;
use PandoraFMS::PredictionServer;

# Global vars
my %Config;
my @Servers;
my $DBH;

########################################################################################
# Server shutdown. Handler to do a controlled shutdown.
########################################################################################
sub pandora_shutdown () {
	logger (\%Config, 'Pandora FMS Server \'' . $Config{'servername'} . '\' Shutdown by signal ', 1);

	# Stop servers
	foreach my $server (@Servers) {
		$server->downEvent ();
		$server->stop ();
	}

	print_message (\%Config, ' [*] Shutting down ' . $Config{'servername'} . "(received signal)...\n", 1);
	db_disconnect ($DBH);
	exit (0);
}

########################################################################################
# Server startup.
########################################################################################
sub pandora_startup () {

	# Start logging
	pandora_start_log (\%Config);

	# Connect to the DB
	$DBH = db_connect ('mysql', $Config{'dbname'}, $Config{'dbhost'}, 3306,
					$Config{'dbuser'}, $Config{'dbpass'});

	# Grab config tokens shared with the console and not in the .conf

	pandora_get_sharedconfig (\%Config, $DBH);

	pandora_audit (\%Config, 'Pandora FMS Server Daemon starting', 'SYSTEM', 'System', $DBH);

	# Load servers
	pandora_reset_server (\%Config, $DBH);
	push (@Servers, new PandoraFMS::DataServer (\%Config, $DBH));
	push (@Servers, new PandoraFMS::NetworkServer (\%Config, $DBH));
	push (@Servers, new PandoraFMS::ReconServer (\%Config, $DBH));
	push (@Servers, new PandoraFMS::SNMPServer (\%Config, $DBH));
	push (@Servers, new PandoraFMS::WMIServer (\%Config, $DBH));
	push (@Servers, new PandoraFMS::PluginServer (\%Config, $DBH));
	push (@Servers, new PandoraFMS::PredictionServer (\%Config, $DBH));

	enterprise_hook('load_enterprise_servers', [\@Servers, \%Config, $DBH]);

	# Remove disabled servers
	@Servers = grep { defined ($_) } @Servers;

	# Run
	foreach my $server (@Servers) {
		$server->run ();
	}
}

########################################################################################
# Server restart.
########################################################################################
sub pandora_restart () {

	# Stop the servers
	foreach my $server (@Servers) {
		$server->stop ();
	}

	# Remove the servers
	while (pop (@Servers)) {};
	
	# Close STDERR, redirected by pandora_start_log
	close (STDERR);

	# Wait before trying to start again
	sleep ($Config{'restart_delay'});

	# Start the servers
	pandora_startup ();
}

########################################################################################
# Server crash. Handler to write in the log unhandled errors and write it to console
########################################################################################
sub pandora_crash () {

	my $full_error = "";

	# Avoid show messages about enterprise library loading failurem, VERY 
	# confussing, all of them are warnigs and not critical, and user should be
	# worried about that. If perl has a more "clean" way to avoid this messages
	# will be nice to replace this code, but at this time it's the only way I know

	foreach my $error_line (@_) {
		if ($error_line !~ m/Enterprise/i && $error_line !~ m/Format_XS/i && $error_line !~ m/ConfigLocal/i){
			logger (\%Config, '[E] \'' . $Config{'servername'} . "': $error_line", 1);
		} else {
			if ($error_line !~ m/Can\'t\slocate/) {
				logger (\%Config, '[E] \'' . $Config{'servername'} . "': $error_line", 1);
			} else {
				# Known errors of loading Enterprise, Format_XS and ConfigLocal 
				# modules, non fatal.
				return;
			}
		}
		$full_error .= $error_line;
	}

	logger (\%Config, 'Pandora FMS Server \'' . $Config{'servername'} . '\' unhandled error.', 1);

	# It's interesting show by console problems, not only in logs. This helps
	# to solve stupid problems like Database credential problems for example

	print_message (\%Config, ' [E] Unhandled error in "' . $Config{'servername'} . "\". See more information in logfiles at '/var/log/pandora' \n", 0);
	print_message (\%Config, " Error description:\n", 0);
	print_message (\%Config, $full_error, 0);

}

$SIG{'TERM'} = 'pandora_shutdown';
$SIG{'INT'} = 'pandora_shutdown';

# Error handler needs to be reviewed, Enterprise not found errors are too nasty :(
$SIG{__DIE__} = 'pandora_crash';

# Prevent alarm from bombing the main thread when called within a thread
$SIG{'ALRM'} = 'IGNORE';

# Initialize
pandora_init(\%Config, 'Pandora FMS Server');
pandora_load_config (\%Config);

# Load enterprise module
if (enterprise_load (\%Config) == 0) {
	print_message (\%Config, " [*] Pandora FMS Enterprise module not available.", 1);
} else {
	print_message (\%Config, " [*] Pandora FMS Enterprise module loaded.", 1);
}

# Daemonize and put in background
if ($Config{'daemon'} == 1) {
	print_message (\%Config, " [*] Backgrounding Pandora FMS Server process.\n", 1);
	pandora_daemonize (\%Config);
}

# Start the servers
pandora_startup ();

# Generate 'going up' events
foreach my $server (@Servers) {
	$server->upEvent ();
}

# Main loop
my $time_ref = time ();
my $counter = 0;

while (1) {

	eval {

		# TASKS DONE EACH 5 SECONDS (Low latency tasks)
		# ---------------------------------------------
		# Server status update each 5 seconds
		# Neightbourhood problem detection each 5 seconds
		# Forced alerts each 5 seconds as well
		if (($counter % 5) == 0) {
		
			# Update server status
			foreach my $server (@Servers) {
				die ($server->getErrStr ()) unless ($server->checkThreads () == 1);
				$server->update ();
			}

			# Update fallen servers
			db_do ($DBH, "UPDATE tserver SET status = 0 WHERE keepalive < ?", strftime ("%Y-%m-%d %H:%M:%S", localtime(time() - $Config{'keepalive'})));

			# Update forced alerts
			pandora_exec_forced_alerts (\%Config, $DBH);

		}

		# TASKS DONE EACH 30 SECONDS (Med latency tasks)
		# ---------------------------------------------
		# Tasks executed only each Server Threshold x 30 secs, for low-priority tasks
		if (($counter % 30) == 0) {

			# Keepalive module control.(very DB intensive, not run frecuently
			pandora_module_keep_alive_nd (\%Config, $DBH);

			# Multicast status report each 30 x Server Threshold secs
			enterprise_hook('mcast_status_report', [\%Config, $DBH]);
		}

		# TASKS DONE EACH 60 SECONDS (Low latency tasks)
		# ---------------------------------------------
		if (($counter % 60) == 0) {
			# Downtimes are executed only 30 x Server Threshold secs
			pandora_planned_downtime (\%Config, $DBH);

			# Realtime stats (Only master server!) - ( VERY HEAVY !)
			# Realtimestats == 1, generated by WEB Console, not by server!
			if ($Config{"pandora_master"} == 1 
				&& defined($Config{"realtimestats"}) 
				&& $Config{"realtimestats"} == 0){ 			

				# Check if I need to refresh stats
				my $last_execution_stats = get_db_value ($DBH, "SELECT MAX(utimestamp) FROM tgroup_stat");
				if (!defined($last_execution_stats) || $last_execution_stats < (time() - $Config{"stats_interval"})){
					pandora_group_statistics (\%Config, $DBH);
					pandora_server_statistics (\%Config, $DBH);
				}

				# Pandora self monitoring
				if (defined($Config{"self_monitoring"}) 
				&& $Config{"self_monitoring"} == 1){
					pandora_self_monitoring (\%Config, $DBH);
				}
			}
		}
	};

	# Restart on error or auto restart
	if ($@) {

		if ($Config{'restart'} eq '0') {
			print_message (\%Config, $@, 1);
			pandora_shutdown ();
		}

		# Generate 'restarting' events
		foreach my $server (@Servers) {
			$server->restartEvent ($@);
		}

		logger (\%Config, 'Pandora FMS Server restarting (' . $@ . ') in ' . $Config{'restart_delay'} . ' seconds.', 1);
		pandora_restart ();
	} elsif (($Config{'auto_restart'} > 0) && (time () - $time_ref > $Config{'auto_restart'})) {
		$time_ref = time ();

		# Mute
		open(OLDOUT, ">&STDOUT");
		open (STDOUT, '>/dev/null');

		# Restart
		pandora_restart ();
		
		# Unmute
		open(STDOUT, ">&OLDOUT");
		close (OLDOUT);
	}

	# Avoid counter overflow
	if ($counter > 10000){
		$counter = 0;
	} else {
		$counter++;
	}

	threads->yield;
	sleep (1);

}