pandorafms/pandora_agents/unix/pandora_agent

#!/usr/bin/perl
# **********************************************************************
# Pandora FMS Generic Unix/Perl Agent
# (c) 2010 Artica Soluciones Tecnológicas
# with the help of many people. Please see http://pandorafms.org
# This code is licensed under GPL 2.0 license.
# **********************************************************************

=head1 NAME

pandora_agent - Pandora FMS Agent

=head1 VERSION

Version 3.2

=head1 USAGE

C<< pandora_agent F<pandora home> >>

=cut


use strict;
use warnings;

use POSIX qw(strftime floor);
use Sys::Hostname;
use File::Basename;
use File::Copy;
use IO::Socket;

# Agent XML data
my $Xml;

# Semaphore used to acces $Xml
my $Sem = undef;

# Semaphore used to control the number of threads
my $ThreadSem = undef;

# Load thread support
eval {
	local $SIG{__DIE__};
	require threads;
	require threads::shared;
	require Thread::Semaphore;
};
if (!$@) {
	$Sem = Thread::Semaphore->new;
	threads::shared::share (\$Xml);
	threads::shared::share (\$Sem);
}	

use constant AGENT_VERSION => '3.2';
use constant AGENT_BUILD => '101227';

# Commands to retrieve total memory information in kB
use constant TOTALMEMORY_CMDS => {
	linux => 'cat /proc/meminfo | grep MemTotal: | awk \'{ print $2 }\'',
	solaris => 'MEM=`prtconf | grep Memory | awk \'{print $3}\'` bash -c \'echo $(( 1024 * $MEM ))\'',
	hpux => 'swapinfo -t | grep memory | awk \'{print $2}\'',
	freebsd => 'sysctl hw.physmem | awk \'{print $2 / 1024}\''
};

# Commands to retrieve free memory information in kB
use constant FREEMEMORY_CMDS => {
	linux => 'cat /proc/meminfo | grep MemFree: | awk \'{ print $2 }\'',
	solaris => 'vmstat 1 2 | tail -1 | awk \'{ print $5 }\'',
	hpux => 'swapinfo -t | grep memory | awk \'{print $4}\'',
	freebsd => 'vmstat -H 1 2 | tail -1 | awk \'{ print $5 }\''
};

# Commands to retrieve cpu information
use constant CPUUSAGE_CMDS => {
	linux => 'vmstat 1 2 | tail -1 | awk \'{ print $13 }\'',
	solaris => 'vmstat 1 2 | tail -1 | awk \'{ print $21 }\'',
	hpux => 'vmstat 1 2 | tail -1 | awk \'{ print $16 }\'',
	freebsd => 'vmstat -n 0 1 2 | tail -1 | awk \'{ print $15 }\''
};

# Commands to retrieve process information
use constant PROC_CMDS => {
	# cpu usage, memory usage, command name
	linux => 'ps aux | awk \'NR > 1 {ps = ""; for (i = 11; i <= NF; ++i) {ps = (ps " " $i) }; print $3, $6, ps}\'',
	solaris => 'prstat 1 1 | awk \'NR > 1 {split ($10, ps, "/"); cpu = substr ($9, 1, length ($9) - 1); mem = substr ($3, 1, length ($3) - 1); print cpu, mem, ps[1]}\'',
	hpux => 'ps -elf | awk \'NR > 1 {ps = ""; for (i = 15; i <= NF; ++i) {ps = (ps " " $i) }; print 0, $10, ps}\'',
	aix => 'ps aux | awk \'NR > 1 {print $3, $6, $11}\'',
	freebsd => 'ps -axw -o %cpu,%mem,command | awk \'NR > 1 {ps = ""; for (i = 3; i <= NF; ++i) {ps = (ps " " $i) }; print $1, $2, ps}\''
};

# Commands to retrieve partition information in kB
use constant PART_CMDS => {
	# total, available, mount point
	linux => 'df -P | awk \'NR > 1 {print $2, $4, $6}\'',
	solaris => 'df -k | awk \'NR > 1 {print $2, $4, $6}\'',
	hpux => 'df -P | awk \'NR > 1 {print $2, $4, $6}\'',
	aix => 'df -kP | awk \'NR > 1 {print $2, $4, $6}\'',
	freebsd => 'df -k | awk \'NR > 1 {print $2, $4, $6}\''
};
	
# OS and OS version
my $OS = $^O;

my $OS_VERSION;

# Used to calculate the MD5 checksum of a string
use constant MOD232 => 2**32;

# Directory where pandora_agent.conf is located
my $ConfDir = '';

# Pandora FMS agent configuration file
my $ConfFile = 'pandora_agent.conf';

# Configuration tokens
my %Conf = (
	'server_ip' => 'localhost',
	'server_path' => '/var/spool/pandora/data_in',
	'logfile' =>'/var/log/pandora/pandora_agent.log',
	'temporal' => '/var/spool/pandora',
	'interval' => 300,
	'debug' => 0,		
	'agent_name' => hostname (),
	'description' => '',
	'group' => '',
	'encoding' => 'ISO-8859-1',
	'server_port' => 41121,
	'transfer_mode' => 'tentacle',
	'server_pwd' => '',
	'server_ssl' => 'no',
	'server_opts' => '',
	'delayed_startup' => 0,
	'pandora_nice' => 10,
	'cron_mode' => 0,
	'remote_config' => 0,
	'secondary_mode' => 'never',
	'secondary_server_ip' => 'localhost',
	'secondary_server_path' => '/var/spool/pandora/data_in',
	'secondary_server_port' => 41121,
	'secondary_transfer_mode' => 'tentacle',
	'secondary_server_pwd' => 'mypassword',
	'secondary_server_ssl' => 'no',
	'secondary_server_opts' => '',
	'autotime' => 0,
	'timezone_offset' => 0,
	'pandora_exec' => 'pandora_agent_exec',
	'agent_threads' => 1,
	'udp_server_port' => 41122,
	'udp_server_auth_address' => '0.0.0.0',
	'udp_server' => 0,
	'proxy_mode' => 0,
	'proxy_user' => 'pandora'
);

# Modules
my @Modules;

# Plugins
my @Plugins;

# Logfile file handle
my $LogFileFH;

# Agent name MD5;
my $AgentMD5;

# Remote configuration file name
my $RemoteConfFile;

# Remote md5 file name
my $RemoteMD5File;

# Process data
my %Procs = (
	'__utimestamp__' => 0
);

# Partition data
my %Parts = (
	'__utimestamp__' => 0
);

# Collections
my %Collections;

# $DevNull
my $DevNull = '/dev/null';

# Shell command separator
my $CmdSep = ';';

################################################################################
# Print usage information and exit.
################################################################################
sub print_usage () {
	print "\nUsage: $0 <Pandora home>\n\n";
	print "\tPandora home is the directory where pandora_agent.conf is located,\n";
	print "\tby default /etc/pandora.\n\n";
	exit 1;
}

################################################################################
# Print an error message and exit.
################################################################################
sub error ($) {
	my $msg = shift;
	print ("[ERROR] $msg\n\n");
	exit 1;
}

################################################################################
# Recursively delete files and directories.
################################################################################
sub rmrf {
	my $path = shift;
	local *DIR;

	if (-d $path) {
		opendir (DIR, $path) || return;
		while (defined (my $file_name = readdir(DIR))) {
			next if ($file_name eq '.' || $file_name eq '..');
			rmrf ("$path/$file_name");
		}
		closedir (DIR);
		rmdir ($path);
	} else {
		unlink ($path);
	}
}

################################################################################
# Recursively set file permissions.
################################################################################
sub chmodr {
	my ($perm, $path) = @_;
	local *DIR;

	if (-d $path) {
		opendir (DIR, $path) || return;
		while (defined (my $file_name = readdir(DIR))) {
			next if ($file_name eq '.' || $file_name eq '..');
			chmodr ($perm, "$path/$file_name");
		}
		closedir (DIR);
	}
	chmod ($perm, $path);
}

################################################################################
# Open the agent logfile and start logging.
################################################################################
sub start_log () {

	# Get the logfile
	my $log_file_name = read_config ('logfile');
	$log_file_name = '/var/log/pandora/pandora_agent.log' unless defined ($log_file_name);

	# Open it
	open ($LogFileFH, "> $log_file_name") or error ("Could not open log file '$log_file_name' for writing: $!.");
	print "Logging to $log_file_name\n";
}

################################################################################
# Close the agent logfile and stop logging.
################################################################################
sub stop_log () {
	close ($LogFileFH);
}

################################################################################
# Log a message to the agent logfile.
################################################################################
sub log_message ($$;$) {
	my ($source, $msg, $dest) = @_;
	
	if (defined ($dest)) {
		print $dest strftime ('%Y/%m/%d %H:%M:%S', localtime ()) . " - [$source] - $msg\n";
	} else {
		print $LogFileFH strftime ('%Y/%m/%d %H:%M:%S', localtime ()) . " - [$source] - $msg\n";
	}
}

################################################################################
# Read configuration file. Exit on error.
################################################################################
sub read_config (;$) {
	my $token = shift;
	my $module;
	
	error ("File '$ConfDir/$ConfFile' not found.") unless (-e "$ConfDir/$ConfFile");
	open (CONF_FILE, "$ConfDir/$ConfFile") or error ("Could not open file '$ConfDir/$ConfFile': $!.");
	while (my $line = <CONF_FILE>) {
	
		# Skip comments and empty lines
		next if ($line =~ m/^\s*#/) or ($line =~ m/^\s*$/);
		
		# Single token search
		if (defined ($token)) {
			return $2 if ($line =~ /^\s*(\S+)\s+(.*)$/ && $1 eq $token);
			next;
		}

		# Module definition
		if ($line =~ /^\s*module_begin\s*$/) {
			$module = {
				'name' => '',
				'type' => 'generic_data',
				'description' => '',
				'func' => 0,
				'params' => '',
				'description' => '',
				'interval' => 1,
				'timeout' => 0,
				'counter' => 0,
				'max' => undef,
				'min' => undef,
				'post_process' => undef,
				'save' => '',
				'conditions' => [],
				'cron' => '',
				'cron_utimestamp' => 0,
				'cron_interval' => -1
			};
		} elsif ($line =~ /^\s*module_name\s+(.+)$/) {
			$module->{'name'} = $1;
		} elsif ($line =~ /^\s*module_description\s+(.+)$/) {
			$module->{'description'} = $1;
		} elsif ($line =~ /^\s*module_type\s+(\S+)\s*$/) {
			$module->{'type'} = $1;
		} elsif ($line =~ /^\s*module_exec\s+(.+)$/) {
			$module->{'func'} = \&module_exec;
			$module->{'params'} = $1;
		} elsif ($line =~ /^\s*module_cpuusage\s+(.*)$/) {
			$module->{'func'} = \&module_cpuusage;
			$module->{'params'} = $1;
		} elsif ($line =~ /^\s*module_freememory\s+(.*)$/) {
			$module->{'func'} = \&module_freememory;
			$module->{'params'} = $1;
		} elsif ($line =~ /^\s*module_freepercentmemory\s+(.*)$/) {
			$module->{'func'} = \&module_freepercentmemory;
			$module->{'params'} = $1;
		} elsif ($line =~ /^\s*(module_proc|module_service)\s+(.+)$/) {
			$module->{'func'} = \&module_proc;
			$module->{'params'} = $2;
		} elsif ($line =~ /^\s*module_cpuproc\s+(.+)$/) {
			$module->{'func'} = \&module_cpuproc;
			$module->{'params'} = $1;
		} elsif ($line =~ /^\s*module_memproc\s+(.+)$/) {
			$module->{'func'} = \&module_memproc;
			$module->{'params'} = $1;
		} elsif ($line =~ /^\s*module_freedisk\s+(.*)$/) {
			$module->{'func'} = \&module_freedisk;
			$module->{'params'} = $1;
		} elsif ($line =~ /^\s*module_freepercentdisk\s+(.*)$/) {
			$module->{'func'} = \&module_freepercentdisk;
			$module->{'params'} = $1;
		} elsif ($line =~ /^\s*module_occupiedpercentdisk\s+(.*)$/) {
			$module->{'func'} = \&module_occupiedpercentdisk;
			$module->{'params'} = $1;
		} elsif ($line =~ /^\s*module_max\s+(.*)\s*$/) {
			$module->{'max'} = $1;
		} elsif ($line =~ /^\s*module_min\s+(.*)\s*$/) {
			$module->{'min'} = $1;
		} elsif ($line =~ /^\s*module_postprocess\s+(.*)\s*$/) {
			$module->{'post_process'} = $1;
		} elsif ($line =~ /^\s*module_interval\s+(\d+)\s*$/) {
			$module->{'interval'} = $1;

			# Make the module run the first time
			$module->{'counter'} = $1;
		} elsif ($line =~ /^\s*module_timeout\s+(\d+)\s*$/) {
			$module->{'timeout'} = $1;
		} elsif ($line =~ /^\s*module_save\s+(\w+)$/) {
			$module->{'save'} = $1;
		} elsif ($line =~ /^\s*module_condition\s+(.*)$/) {
			my $action = $1;
			# Numeric comparison
			if ($action =~ /^\s*([<>!=]+)\s+(\d+\.\d*)\s+(.*)$/) {
				push (@{$module->{'conditions'}}, {'operator' => $1, 'value_1' => $2, 'command' => $3});
			# Interval
			} elsif ($action =~ /^\s*[(]\s*(\d+\.\d*)\s*,\s*(\d+\.\d*)\s*[)]\s+(.*)$/) {
				push (@{$module->{'conditions'}}, {'operator' => '()', 'value_1' => $1, 'value_2' => $2, 'command' => $3});
			# Regular expression
			} elsif ($action =~ /^\s*=~\s+(\S*)\s+(.*)$/) {
				push (@{$module->{'conditions'}}, {'operator' => '=~', 'value_1' => $1, 'command' => $2});
			}
		} elsif ($line =~ /^\s*module_crontab\s+(((\*|(\d+(-\d+){0,1}))\s*){5}).*$/) {
			$module->{'cron'} = $1;
		} elsif ($line =~ /^\s*module_cron_interval\s+(\d+).*$/) {
			$module->{'cron_interval'} = $1;
		} elsif ($line =~ /^\s*module_end\s*$/) {
			next unless ($module->{'name'} ne '') and ($module->{'func'} != 0);
			push (@Modules, $module);
		# Plugin
		} elsif ($line =~ /^\s*module_plugin\s+(.+)$/) {
			push (@Plugins, $1);
		# Module proc command redefinition		
		} elsif ($line =~ /^\s*module_proc_cmd\s+(.+)$/) {
			PROC_CMDS->{$OS} = $1;
		# Module freedisk command redefinition		
		} elsif ($line =~ /^\s*module_freedisk_cmd\s+(.+)$/) {
			PART_CMDS->{$OS} = $1;
		# Collection
		} elsif ($line =~ /^\s*file_collection\s+(.+)$/) {
			my $collection = $1;
			
			# Prevent path traversal attacks
			if ($collection !~ m/(\.\.)|\//) {
				$Collections{$collection} = 0;
			}
		# Configuration token
		} elsif ($line =~ /^\s*(\S+)\s+(.*)$/) {
			
			log_message ('setup', "$1 is $2");
			$Conf{$1} = $2;
			
			# Remove trailing spaces
			$Conf{$1} =~ s/\s*$//;
		}
	}

	# Token not found
	if (defined ($token)) {
		close (CONF_FILE);
		return undef;
	}

	# Update the agent MD5 since agent_name may have changed
	$AgentMD5 = md5 ($Conf{'agent_name'});
	$RemoteConfFile = "$AgentMD5.conf";
	$RemoteMD5File = "$AgentMD5.md5";
	
	# Set the maximun number of threads
	$ThreadSem = Thread::Semaphore->new ($Conf{'agent_threads'}) if defined ($Sem);

	# Set tentacle client options
	if ($Conf{'transfer_mode'} eq 'tentacle') {
		$Conf{'server_opts'} = '-x \'' . $Conf{'server_pwd'} . '\' ' . $Conf{'server_opts'} if ($Conf{'server_pwd'} ne '');
		$Conf{'server_opts'} = '-c ' . $Conf{'server_opts'} if ($Conf{'server_ssl'} eq 'yes');
	}

	# Set tentacle client options for secondary server	
	if ($Conf{'secondary_transfer_mode'} eq 'tentacle') {
		$Conf{'secondary_server_opts'} = '-x \'' . $Conf{'secondary_server_pwd'} . '\' ' . $Conf{'secondary_server_opts'} if ($Conf{'secondary_server_pwd'} ne '');
		$Conf{'secondary_server_opts'} = '-c ' . $Conf{'secondary_server_opts'} if ($Conf{'secondary_server_ssl'} eq 'yes');		
	}

	close (CONF_FILE);
}

################################################################################
# Remove any trailing / from directory names.
################################################################################
sub fix_directory ($) {
	my $dir = shift;
	
	my $char = chop ($dir);
	return $dir if ($char eq '/');
	return $dir . $char;
}

################################################################################
# Sends a file to the server.
################################################################################
#sub send_file ($;$) {
sub send_file {
	my ($file, $secondary) = @_;
	my $output;

	if ($Conf{'transfer_mode'} eq 'tentacle') {
 		$output = `tentacle_client -v -a $Conf{'server_ip'} -p $Conf{'server_port'} $Conf{'server_opts'} $file 2>&1 >$DevNull`;
	} elsif ($Conf{'transfer_mode'} eq 'ssh') {
 		$output = `scp -P $Conf{'server_port'} $file pandora@"$Conf{'server_ip'}:$Conf{'server_path'}" 2>&1 >$DevNull`;
	} elsif ($Conf{'transfer_mode'} eq 'ftp') {
		my $base = basename ($file);
		my $dir = dirname ($file);

		$output = `ftp -n $Conf{'server_ip'} $Conf{'server_port'} 2>&1 >$DevNull <<FEOF1
		quote USER pandora
		quote PASS $Conf{'server_pwd'}
		lcd "$dir"
		cd "$Conf{'server_path'}"
		put "$base"
		quit
		FEOF1`
	} elsif ($Conf{'transfer_mode'} eq 'local') {
		$output = `cp $file $Conf{'server_path'}/ 2>&1 >$DevNull`;
	}

	# Get the errorlevel
	my $rc = $? >> 8;
	if ($rc != 0) {
		log_message ('error', "Error sending file '$file': $output");
	}

	return $rc unless (defined ($secondary));

	# Send the file to the secondary server
	return $rc unless ($Conf{'secondary_mode'} eq 'always' || ($Conf{'secondary_mode'} eq 'on_error' && $rc != 0));
	
	swap_servers ();
	$rc = send_file ($file);
	swap_servers ();
	return $rc;
}

################################################################################
# Swap primary and secondary servers.
################################################################################
sub swap_servers () {
	($Conf{'server_ip'}, $Conf{'secondary_server_ip'}) = ($Conf{'secondary_server_ip'}, $Conf{'server_ip'});
	($Conf{'server_path'}, $Conf{'secondary_server_path'}) = ($Conf{'secondary_server_path'}, $Conf{'server_path'});
	($Conf{'server_port'}, $Conf{'secondary_server_port'}) = ($Conf{'secondary_server_port'}, $Conf{'server_port'});
	($Conf{'server_transfer_mode'}, $Conf{'secondary_server_transfer_mode'}) = ($Conf{'secondary_server_transfer_mode'}, $Conf{'server_transfer_mode'});
	($Conf{'server_pwd'}, $Conf{'secondary_server_pwd'}) = ($Conf{'secondary_server_pwd'}, $Conf{'server_pwd'});
	($Conf{'server_ssl'}, $Conf{'secondary_server_ssl'}) = ($Conf{'secondary_server_ssl'}, $Conf{'server_ssl'});
	($Conf{'server_opts'}, $Conf{'secondary_server_opts'}) = ($Conf{'secondary_server_opts'}, $Conf{'server_opts'});
}

################################################################################
# Receive a file from the server.
################################################################################
sub recv_file ($) {
	my $file = shift;
	my $output;

	if ($Conf{'transfer_mode'} eq 'tentacle') {
 		$output = `cd "$Conf{'temporal'}"$CmdSep tentacle_client -v -g -a $Conf{'server_ip'} -p $Conf{'server_port'} $Conf{'server_opts'} $file 2>&1 >$DevNull`
	} elsif ($Conf{'transfer_mode'} eq 'ssh') {
 		$output = `scp -P $Conf{'server_port'} pandora@"$Conf{'server_ip'}:$Conf{'server_path'}/$file" $Conf{'temporal'} 2>&1 >$DevNull`;
	} elsif ($Conf{'transfer_mode'} eq 'ftp') {
		my $base = basename ($file);
		my $dir = dirname ($file);

		$output = `ftp -n $Conf{'server_ip'} $Conf{'server_port'} 2>&1 >$DevNull <<FEOF1
		quote USER pandora
		quote PASS $Conf{'server_pwd'}
		lcd "$Conf{'temporal'}"
		cd "$Conf{'server_path'}"
		get "$file"
		quit
		FEOF1`
	} elsif ($Conf{'transfer_mode'} eq 'local') {
		$output = `cp $Conf{'server_path'}/$file $Conf{'temporal'} 2>&1 >$DevNull`;
	}

	# Get the errorlevel
	my $rc = $? >> 8;
	if ($rc != 0) {
		log_message ('error', "Error retrieving file: $output");
	}

	return $rc;
}

################################################################################
# Check the server for a remote configuration.
################################################################################
sub check_remote_config () {

	return unless ($Conf{'remote_config'} eq '1');

	# Calculate the configuration file MD5 digest
	open (CONF_FILE, "$ConfDir/$ConfFile") or error ("Could not open file '$ConfDir/$ConfFile': $!.");
	binmode(CONF_FILE);
	my $conf_md5 = md5 (join ('', <CONF_FILE>));
	close (CONF_FILE);

	# Get the remote MD5 file
	if (recv_file ($RemoteMD5File) != 0) {
		open (MD5_FILE, "> $Conf{'temporal'}/$RemoteMD5File") || error ("Could not open file '$ConfDir/$RemoteMD5File' for writing: $!.");
		print MD5_FILE $conf_md5;
		close (MD5_FILE);
		copy ("$ConfDir/$ConfFile", "$Conf{'temporal'}/$RemoteConfFile");
		send_file ("$Conf{'temporal'}/$RemoteConfFile");
		send_file ("$Conf{'temporal'}/$RemoteMD5File");
		log_message ('remote config', 'Uploading configuration for the first time.');
		unlink ("$Conf{'temporal'}/$RemoteConfFile");
		unlink ("$Conf{'temporal'}/$RemoteMD5File");
		return;
	}

	open (MD5_FILE, "< $Conf{'temporal'}/$RemoteMD5File") || error ("Could not open file '$ConfDir/$RemoteMD5File' for writing: $!.");
	my $remote_conf_md5 = <MD5_FILE>;
	close (MD5_FILE);
	
	# No changes
	return if ($remote_conf_md5 eq $conf_md5);
	
	# Get the new configuration file
	return if (recv_file ($RemoteConfFile) != 0);
	log_message ('remote config', 'Configuration has changed!');

	# Empty modules, plugins and collections
	@Modules = ();
	@Plugins = ();
	%Collections = ();

	# Save the new configuration and reload it
	move ("$Conf{'temporal'}/$RemoteConfFile", "$ConfDir/$ConfFile");
	read_config ();
	
	# Log file may have changed
	stop_log ();
	start_log ();
	
	#Set nice of the pandora_agent
	my $PID = $$;
	`renice "$Conf{'pandora_nice'}" "$PID"`;
}

################################################################################
# SUB launch_tentacle_proxy
# Launchs tentacle server in proxy mode.
################################################################################
sub launch_tentacle_proxy () {
		
	# Check if proxy mode is enable.
	if ($Conf{'proxy_mode'}) {		
			
		my $auxPid = fork();	
		
		if (! $auxPid) {
			
			my $new_process = "sudo -u ".$Conf{'proxy_user'}." tentacle_server -b ".$Conf{'server_ip'}." -g ".$Conf{'server_port'};

			log_message ('setup', 'Proxy mode enabled');	
					
			exec ($new_process);		
		}
	}
}

################################################################################
# Delete old collections and download new collections.
################################################################################
sub check_collections () {

	# Delete old collections
	opendir (DIR, "$ConfDir/collections") || return;
 	while (defined (my $file_name = readdir(DIR))) {
		next if ($file_name eq '.' || $file_name eq '..');

		# Do not delete md5 files associated to a collection
		$file_name =~ s/\.md5$//;

		if (! defined ($Collections{$file_name})) {
			rmrf ("$ConfDir/collections/$file_name");
			unlink ("$ConfDir/collections/$file_name.md5");
		}
	}
	closedir (DIR);

	# Download new collections
	while (my ($collection, $in_path) = each (%Collections)) {
		my $collection_file = $collection . ".zip";
		my $collection_md5_file = $collection . ".md5";

		# Add the collection directory to the PATH
		if ($in_path == 0) {
			$Collections{$collection} = 1;
			$ENV{'PATH'} .= ":$ConfDir/collections/$collection";
		}

		# Get remote md5
		next unless (recv_file ($collection_md5_file) == 0);
		open (MD5_FILE, "< $Conf{'temporal'}/$collection_md5_file") || error ("Could not open file '$Conf{'temporal'}/$collection_md5_file' for reading: $!.");
		my $remote_collection_md5 = <MD5_FILE>;
		close (MD5_FILE);
		unlink ("$Conf{'temporal'}/$collection_md5_file");

		# Read local md5
		my $local_collection_md5 = '';
		if (defined (open (MD5_FILE, "< $ConfDir/collections/$collection_md5_file"))) {
			$local_collection_md5 = <MD5_FILE>;
			close MD5_FILE;
		}

		# Check for changes
		$local_collection_md5 = $remote_collection_md5 unless defined ($local_collection_md5);
		next if ($local_collection_md5 eq $remote_collection_md5);
		
		# Download and unzip
		next unless (recv_file ($collection_file) == 0);
		rmrf ("$ConfDir/collections/$collection");
		`unzip -d "$ConfDir/collections/$collection" "$Conf{'temporal'}/$collection_file" 2>$DevNull`;
		unlink ("$Conf{'temporal'}/$collection_file");		
		
		# Save the new md5
		open (MD5_FILE, "> $ConfDir/collections/$collection_md5_file") || error ("Could not open file '$ConfDir/collections/$collection_md5_file' for writing: $!.");
		print MD5_FILE "$remote_collection_md5";
		close (MD5_FILE);
		
		# Set proper file permissions
		chmodr (0750, "$ConfDir/collections/$collection");
	}
}

###############################################################################
# MD5 leftrotate function. See http://en.wikipedia.org/wiki/MD5#Pseudocode.
###############################################################################
sub leftrotate ($$) {
	my ($x, $c) = @_;

	return (0xFFFFFFFF & ($x << $c)) | ($x >> (32 - $c));
}

###############################################################################
# Initialize some variables needed by the MD5 algorithm.
# See http://en.wikipedia.org/wiki/MD5#Pseudocode.
###############################################################################
my (@R, @K);
sub md5_init () {

	# R specifies the per-round shift amounts
	@R = (7, 12, 17, 22,  7, 12, 17, 22,  7, 12, 17, 22,  7, 12, 17, 22,
		  5,  9, 14, 20,  5,  9, 14, 20,  5,  9, 14, 20,  5,  9, 14, 20,
		  4, 11, 16, 23,  4, 11, 16, 23,  4, 11, 16, 23,  4, 11, 16, 23,
		  6, 10, 15, 21,  6, 10, 15, 21,  6, 10, 15, 21,  6, 10, 15, 21);

	# Use binary integer part of the sines of integers (radians) as constants
	for (my $i = 0; $i < 64; $i++) {
		$K[$i] = floor(abs(sin($i + 1)) * MOD232);
	}
}

###############################################################################
# Return the MD5 checksum of the given string. 
# Pseudocode from http://en.wikipedia.org/wiki/MD5#Pseudocode.
###############################################################################
sub md5 ($) {
	my $str = shift;

	# Note: All variables are unsigned 32 bits and wrap modulo 2^32 when calculating

	# Initialize variables
	my $h0 = 0x67452301;
	my $h1 = 0xEFCDAB89;
	my $h2 = 0x98BADCFE;
	my $h3 = 0x10325476;

	# Pre-processing
	my $msg = unpack ("B*", pack ("A*", $str));
	my $bit_len = length ($msg);

	# Append "1" bit to message
	$msg .= '1';

	# Append "0" bits until message length in bits ≡ 448 (mod 512)
	$msg .= '0' while ((length ($msg) % 512) != 448);

	# Append bit /* bit, not byte */ length of unpadded message as 64-bit little-endian integer to message
	$msg .= unpack ("B64", pack ("VV", $bit_len));

	# Process the message in successive 512-bit chunks
	for (my $i = 0; $i < length ($msg); $i += 512) {

		my @w;
		my $chunk = substr ($msg, $i, 512);

		# Break chunk into sixteen 32-bit little-endian words w[i], 0 <= i <= 15
		for (my $j = 0; $j < length ($chunk); $j += 32) {
			push (@w, unpack ("V", pack ("B32", substr ($chunk, $j, 32))));
		}

		# Initialize hash value for this chunk
		my $a = $h0;
		my $b = $h1;
		my $c = $h2;
		my $d = $h3;
		my $f;
		my $g;

		# Main loop
		for (my $y = 0; $y < 64; $y++) {
			if ($y <= 15) {
				$f = $d ^ ($b & ($c ^ $d));
				$g = $y;
			}
			elsif ($y <= 31) {
				$f = $c ^ ($d & ($b ^ $c));
				$g = (5 * $y + 1) % 16;
			}
			elsif ($y <= 47) {
				$f = $b ^ $c ^ $d;
				$g = (3 * $y + 5) % 16;
			}
			else {
				$f = $c ^ ($b | (0xFFFFFFFF & (~ $d)));
				$g = (7 * $y) % 16;
			}

			my $temp = $d;
			$d = $c;
			$c = $b;
			$b = ($b + leftrotate (($a + $f + $K[$y] + $w[$g]) % MOD232, $R[$y])) % MOD232;
			$a = $temp;
		}

		# Add this chunk's hash to result so far
		$h0 = ($h0 + $a) % MOD232;
		$h1 = ($h1 + $b) % MOD232;
		$h2 = ($h2 + $c) % MOD232;
		$h3 = ($h3 + $d) % MOD232;
	}

	# Digest := h0 append h1 append h2 append h3 #(expressed as little-endian)
	return unpack ("H*", pack ("V", $h0)) . unpack ("H*", pack ("V", $h1)) . unpack ("H*", pack ("V", $h2)) . unpack ("H*", pack ("V", $h3));
}

################################################################################
# Try to guess the OS version.
################################################################################
sub guess_os_version ($) {
	my $os = shift;
	my $os_version;

	# Linux
	if ($os eq 'linux') {
		$os_version = `lsb_release -sd 2>$DevNull`;
	# AIX
	} elsif ($os eq 'aix') {
		$os_version = "$2.$1" if (`uname -rv` =~ /\s*(\d)\s+(\d)\s*/);
	# Windows
	} elsif ($os =~ /win/i) {
		$os_version = `ver`;
		$DevNull = '/Nul';
		$CmdSep = '\&';
		$OS = "windows";

	# Solaris, HP-UX, BSD and others
	} else {
		$os_version = `uname -r`;
	}
	
	# Something went wrong
	return '' unless defined ($os_version);
	
	# Remove any trailing new lines
	chomp ($os_version);

	return $os_version;
}

################################################################################
# Execute the given module.
################################################################################
sub exec_module ($) {
	my $module = shift;

	# Need something to execute
	if ($module->{'func'} == 0) {
		$ThreadSem->up () if (defined ($ThreadSem) && $Conf{'agent_threads'} > 1);
		return;
	}
	
	# Check module interval
	if (++($module->{'counter'}) < $module->{'interval'}) {
		$ThreadSem->up () if (defined ($ThreadSem) && $Conf{'agent_threads'} > 1);
		return;
	}

	# Check module cron
	if (check_module_cron ($module) != 1) {
		$ThreadSem->up () if (defined ($ThreadSem) && $Conf{'agent_threads'} > 1);
		return;
	}
	
	# Reset module counter
	$module->{'counter'} = 0;

	# Temporarily disable strict refs
	no strict 'refs';

	# Run
	my @value = &{$module->{'func'}}($module);
	
	# Save the module value if needed (only works for the first returned value)
	if ($module->{'save'} ne '') {
		if (defined ($value[0])) {
			$ENV{$module->{'save'}} = $value[0] ;
		} else {
			$ENV{$module->{'save'}} = '';
		}
	}

	write_module_xml ($module, @value);
	
	$ThreadSem->up () if (defined ($ThreadSem) && $Conf{'agent_threads'} > 1);
}

################################################################################
# Load process information.
################################################################################
sub load_procs () {
	my $utimestamp = time ();

	# Do we know hoy to get process information in this OS?
	return unless defined (PROC_CMDS->{$OS});

	# Update at most once every interval
	return if ($Procs{'__utimestamp__'} > ($utimestamp - $Conf{'interval'}));

	# Get process information
	my $cmd = PROC_CMDS->{$OS};
	my @procs = `$cmd`;
	return undef unless ($? eq 0);

	# Discard the header
	shift (@procs);

	# Parse process information
	foreach my $proc (@procs) {

		chomp ($proc);		
		my @proc_info = split (/\s+/, $proc);
		next unless ($#proc_info >= 2);

		# Process command
		my $proc_cmd = join (' ', @proc_info[2..$#proc_info]);

		# Process command
		$Procs{$proc_cmd} = ();
		
		# Process CPU usage
		$Procs{$proc_cmd}{'cpu'} = $proc_info[0];

		# Process virtual size
		$Procs{$proc_cmd}{'size'} = $proc_info[1];
	}

	$Procs{'__utimestamp__'} = $utimestamp;
}

################################################################################
# Load partition information.
################################################################################
sub load_parts () {
	my $utimestamp = time ();

	# Do we know hoy to get partition information in this OS?
	return unless defined (PART_CMDS->{$OS});

	# Update at most once every interval
	return if ($Parts{'__utimestamp__'} > ($utimestamp - $Conf{'interval'}));

	# Get partition information
	my $cmd = PART_CMDS->{$OS};
	my @parts = `$cmd`;
	return undef unless ($? eq 0);

	# Parse partition information
	foreach my $part (@parts) {

		chomp ($part);		
		my @part_info = split (/\s+/, $part);
		next unless ($#part_info >= 2);
		
		my $part = join (' ', @part_info[2..$#part_info]);

		# Mount point
		$Parts{$part} = ();
		
		# Total space in kB
		$Parts{$part}{'total'} = $part_info[0];

		# Available space in kB
		$Parts{$part}{'avail'} = $part_info[1];
	}

	$Parts{'__utimestamp__'} = $utimestamp;
}

################################################################################
# Execute the given command.
################################################################################
sub module_exec ($) {
	my $module = shift;
	my @data;

	# Check module parameters
	return () unless ($module->{'params'} ne '');

	# Execute the command
	if ($module->{'timeout'} == 0) {
		@data = `$module->{'params'} 2> $DevNull`;
	} else {
		my $cmd = quotemeta ($module->{'params'});
		@data = `$Conf{'pandora_exec'} $module->{'timeout'} $cmd 2> $DevNull`;
	}

	# Something went wrong or no data
	return () unless ($? eq 0 && defined ($data[0]));

	# Evaluate module conditions
	evaluate_module_conditions ($module, $data[0]);

	return @data;
}

################################################################################
# Get the status of a process. 1 running, 0 not running.
################################################################################
sub module_proc ($) {
	my $module = shift;

	# Check module parameters
	return () unless ($module->{'params'} ne '');

	# Data collection layer
	load_procs ();

	return (1) if defined ($Procs{$module->{'params'}});
	return (0);
}

################################################################################
# Get the CPU usage of a process.
################################################################################
sub module_cpuproc ($) {
	my $module = shift;

	# Check module parameters
	return () unless ($module->{'params'} ne '');

	return () unless defined ($Procs{$module->{'params'}}) and defined ($Procs{$module->{'params'}}{'cpu'});
	return ($Procs{$module->{'params'}}{'cpu'});
}

################################################################################
# Get the memory usage of a process in Mbytes.
################################################################################
sub module_memproc ($) {
	my $module = shift;

	# Check module parameters
	return () unless ($module->{'params'} ne '');

	# Data collection layer
	load_procs ();

	return () unless defined ($Procs{$module->{'params'}}) and defined ($Procs{$module->{'params'}}{'size'});
	return (sprintf ("%d", $Procs{$module->{'params'}}{'size'} / 1024));
}

################################################################################
# Get the free space in a partition in Mbytes.
################################################################################
sub module_freedisk ($) {
	my $module = shift;

	# Check module parameters
	return () unless ($module->{'params'} ne '');

	# Data collection layer
	load_parts ();

	return () unless defined ($Parts{$module->{'params'}}) and defined ($Parts{$module->{'params'}}{'avail'});
	
	my $avail = sprintf("%d", $Parts{$module->{'params'}}{'avail'} / 1024);
	return ($avail);
}

################################################################################
# Get the free space in a partition in %.
################################################################################
sub module_freepercentdisk ($) {
	my $module = shift;

	# Check module parameters
	return () unless ($module->{'params'} ne '');

	# Data collection layer
	load_parts ();

	return () unless defined ($Parts{$module->{'params'}}) and defined ($Parts{$module->{'params'}}{'avail'});
	
	my $availp = sprintf("%d", $Parts{$module->{'params'}}{'avail'} * 100 / $Parts{$module->{'params'}}{'total'});
	return ($availp);
}

################################################################################
# Get the occupied space in a partition in %.
################################################################################
sub module_occupiedpercentdisk ($) {
	my $module = shift;

	# Check module parameters
	return () unless ($module->{'params'} ne '');

	# Data collection layer
	load_parts ();

	return () unless defined ($Parts{$module->{'params'}}) and defined ($Parts{$module->{'params'}}{'avail'});
	
	my $occupiedp = sprintf("%d", ($Parts{$module->{'params'}}{'total'} - $Parts{$module->{'params'}}{'avail'}) * 100 / $Parts{$module->{'params'}}{'total'});
	return ($occupiedp);
}

################################################################################
# Get the CPU usage %.
################################################################################
sub module_cpuusage ($) {
	my $module = shift;

	# Do we know hoy to get CPU usage in this OS?
	return unless defined (CPUUSAGE_CMDS->{$OS});

	# Get CPU usage
	my $cmd = CPUUSAGE_CMDS->{$OS};
	my @data = `$cmd 2> $DevNull`;

	# Something went wrong or no data
	return () unless ($? eq 0 && defined ($data[0]));

	return ($data[0]);
}

################################################################################
# Get the free space in a partition in Mbytes.
################################################################################
sub module_freememory ($) {
	my $module = shift;

	# Do we know hoy to get memory information in this OS?
	return () unless defined (FREEMEMORY_CMDS->{$OS});

	# Get available memory
	my $cmd = FREEMEMORY_CMDS->{$OS};
	my @data = `$cmd 2> $DevNull`;

	# Something went wrong or no data
	return () unless ($? eq 0 && defined ($data[0]));

	return (sprintf ("%d", $data[0] / 1024));
}

################################################################################
# Get the free space in a partition in %.
################################################################################
sub module_freepercentmemory ($) {
	my $module = shift;

	# Do we know hoy to get memory information in this OS?
	return unless defined (TOTALMEMORY_CMDS->{$OS});

	# Get CPU usage
	my $cmd = TOTALMEMORY_CMDS->{$OS};
	my @data = `$cmd 2> $DevNull`;

	# Something went wrong or no data
	return () unless ($? eq 0 && defined ($data[0]));

	# Get total memory in MB
	my $total = sprintf ("%d", $data[0] / 1024);
	
	# Get available memory in MB
	my ($avail) = module_freememory ($module);
	return () unless defined ($avail);
	
	return sprintf (("%d", $avail * 100 / $total));
}

################################################################################
# Evaluate and execute module conditions.
################################################################################
sub evaluate_module_conditions ($$) {
	my ($module, $data) = @_;

	# Evaluate conditions
	foreach my $condition (@{$module->{'conditions'}}) {
		if (($condition->{'operator'} eq '>' && $data > $condition->{'value_1'}) ||
			($condition->{'operator'} eq '<' && $data < $condition->{'value_1'}) ||
			($condition->{'operator'} eq '=' && $data == $condition->{'value_1'}) ||
			($condition->{'operator'} eq '!=' && $data != $condition->{'value_1'}) ||
			($condition->{'operator'} eq '=~' && $data =~ /$condition->{'value_1'}/) ||
			($condition->{'operator'} eq '()' && $data > $condition->{'value_1'} && $data < $condition->{'value_2'})) {
				`$condition->{'command'} 2> $DevNull`;
		}
	}
}

################################################################################
# Checks the module's cron string. Returns 1 if the module should be run, 0 if
# not.
################################################################################
sub check_module_cron ($) {
	my $module = shift;
	
	# No cron string defined
	return 1 unless ($module->{'cron'} ne '');

	# Check if the module was already executed
	return 0 unless (time() > $module->{'cron_utimestamp'});

	# Get cron configuration
	my @cron_params = split (/\s/, $module->{'cron'});

	# Get current time
	my $current_time = time();
	my @time = localtime($current_time);

	# Minutes, hours, day of the month, month and day of the week
	my @time_params = @time[1, 2, 3, 4, 6];

	# Fix month (localtime retuns 0..11 and we need 1..12)
	$time_params[3] += 1;
	
	# Check cron parameters	
	for (my $i = 0; $i < 5; $i++) {
		
		# Wildcard
		next if ($cron_params[$i] eq '*');
		
		# Get interval
		my ($bottom, $top) = split (/-/, $cron_params[$i]);
		$top = $bottom unless defined ($top);
		
		# Check interval
		if ($bottom <= $top) {
			return 0 if ($time_params[$i] < $bottom || $time_params[$i] > $top);
		} else {
			return 0 if ($time_params[$i] < $bottom && $time_params[$i] > $top);
		}
	}

	# Do not check in the next minute, hour, day or month.
	my $offset = 0; 
	if ($module->{'cron_interval'} >= 0) {
		$offset = $module->{'cron_interval'};
	} elsif($cron_params[0] ne '*') {
		# 1 minute
		$offset = 60;
	} elsif($cron_params[1] ne '*') {
		# 1 hour
		$offset = 3600;
	} elsif($cron_params[2] ne '*' || $cron_params[4] ne '*') {
		# 1 day
		$offset = 86400;
	} elsif($cron_params[3] ne '*') {
		# 31 days
		$offset = 2678400;
	}

	$module->{'cron_utimestamp'} = $current_time + $offset;
	return 1;
}

################################################################################
# Write module data in XML format.
################################################################################
sub write_module_xml ($@) {
	my ($module, @data) = @_;

	# No data
	return unless (defined $data[0]);

	# Critical section
	$Sem->down () if (defined ($Sem));

	$Xml .= "	<module>\n" .
		"	<name><![CDATA[" . $module->{'name'} . "]]></name>\n" .
		"	<description><![CDATA[" . $module->{'description'} . "]]></description>\n" . 
		"	<type>" . $module->{'type'} . "</type>\n";

	# Interval
	$Xml .= "	<module_interval>" . $module->{'interval'} . "</module_interval>\n" if ($module->{'interval'} > 1);
	
	# Min
	$Xml .= "	<min>" . $module->{'min'} . "</min>\n" if (defined ($module->{'min'}));

	# Max
	$Xml .= "	<max>" . $module->{'max'} . "</max>\n" if (defined ($module->{'max'}));

	# Post process
	$Xml .= "	<post_process>" . $module->{'post_process'} . "</post_process>\n" if (defined ($module->{'post_process'}));

	# Data list
	if ($#data > 0) {
		$Xml .= "	<datalist>\n";
		foreach my $data_item (@data) {
			chomp ($data_item);
			$Xml .= "	<data><value><![CDATA[$data_item]]></value></data>\n";
		}
		$Xml .= "	</datalist>\n";
	# Single data
	} else {
		chomp ($data[0]);
		$Xml .= "	<data><![CDATA[$data[0]]]></data>\n";
	}
	$Xml .= "	</module>\n";

 	$Sem->up () if (defined ($Sem));
}

################################################################################
# Receive a UDP server signal to restart agent
################################################################################
sub udp_server_signal () {
	log_message ('udp server', 'Received signal to restart the agent.');
}

################################################################################
# Basic UDP server to restart agent on UDP signal received
################################################################################
sub udp_server ($$) {

	my $udp_port = shift;
	my $udp_auth_address = shift;
	my $parent_pid = getppid();

	my($sock, $oldmsg, $newmsg, $hisaddr, $hishost, $MAXLEN);
	$MAXLEN = 1024;

	log_message ('udp server', 'Starting UDP server listening on '.$udp_auth_address.":".$udp_port);
	$sock = IO::Socket::INET->new(LocalPort => $udp_port, Proto => 'udp') or die "socket: $@";

	while ($sock->recv($newmsg, $MAXLEN)) {
		my($port, $ipaddr) = sockaddr_in($sock->peername);
		$hishost = gethostbyaddr($ipaddr, AF_INET);

		log_message ('udp server', 'Received signal from '.$hishost);

		if (($udp_auth_address eq "0.0.0.0") || ($hishost eq $udp_auth_address)){
			if ($newmsg =~ /REFRESH AGENT/){
				# Send signal to restart agent
				kill 'SIGINT' , $parent_pid;
			}
		}
	}
}

################################################################################
# Execute the given plugin.
################################################################################
sub exec_plugin ($) {
	my $plugin = shift;

	my $output = `$plugin 2>$DevNull`;

	# Do not save the output if there was an error
	if ($? != 0) {
		$ThreadSem->up () if (defined ($ThreadSem) && $Conf{'agent_threads'} > 1);
		return;
	}

	# Critical section
	$Sem->down () if (defined ($Sem));
	$Xml .= $output;
 	$Sem->up () if (defined ($Sem));

	$ThreadSem->up () if (defined ($ThreadSem) && $Conf{'agent_threads'} > 1);
}

################################################################################
# Main.
################################################################################

# Check command line arguments
print_usage unless ($#ARGV == 0);
$ConfDir = fix_directory ($ARGV[0]);
error ("Directory '$ConfDir' does not exist.") unless (-d "$ConfDir");

# Get user to run as
my $pandora_user = read_config ('pandora_user');
if (defined ($pandora_user)) {
	# Change the EUID
	my $pandora_user_uid = getpwnam ($pandora_user);
	if (!defined ($pandora_user_uid)) {
		error ("Cannot get uid for user $pandora_user. Does the user exist and can we read /etc/passwd?");
	}
	$> = $pandora_user_uid;
	if ($> != $pandora_user_uid) {
		error ("Cannot run as $pandora_user: Insufficient permissions.");
	}
}

# Guess the OS version
$OS_VERSION = guess_os_version ($OS);

# Initialize MD5 variables
md5_init ();

# Start logging
start_log ();
log_message ('log', 'Running as user ' . getpwuid ($>));

# Read configuration file
read_config ();

# Fix directory names
$Conf{'temporal'} = fix_directory ($Conf{'temporal'});
error ("Temporal directory '" . $Conf{'temporal'} . "' does not exist.") unless (-d "$Conf{'temporal'}");
$Conf{'server_path'} = fix_directory ($Conf{'server_path'});
$Conf{'secondary_server_path'} = fix_directory ($Conf{'secondary_server_path'});

# Startup delay
log_message ('log', 'Sleeping for ' . $Conf{'delayed_startup'} . ' seconds.') if ($Conf{'delayed_startup'} > 0);
sleep ($Conf{'delayed_startup'});

#Set nice of the pandora_agent
my $PID = $$;
`renice "$Conf{'pandora_nice'}" "$PID"`;

#Launch tentacle server in proxy mode if needed
launch_tentacle_proxy();

# Add the plugins directory to the PATH
$ENV{'PATH'} .= ":$ConfDir/plugins";

# Start UDP server if configured
if ($Conf{'udp_server'} == 1){
	my $pid = fork();

	if ($pid == 0){
		udp_server ($Conf{'udp_server_port'}, $Conf{'udp_server_auth_address'});
		exit;
	}
}


# Loop
while (1) {

	# Ignore signals from UDP server while processing execution
	if ($Conf{'udp_server'} == 1){
		$SIG{'INT'} = 'DEFAULT';
	}

	# Check for a new configuration
	check_remote_config () unless ($Conf{'debug'} eq '1');

	# Check file collections
	check_collections () unless ($Conf{'debug'} eq '1');

	$Xml = "<?xml version='1.0' encoding='" . $Conf{'encoding'} . "'?>\n" .
		"<agent_data description='" . $Conf{'description'} ."' group='" . $Conf{'group'} .
		"' os_name='$OS' os_version='$OS_VERSION' interval='" . $Conf{'interval'} .
		"' version='" . AGENT_VERSION . '(Build ' . AGENT_BUILD . ')' . ($Conf{'autotime'} eq '1' ? '' : "' timestamp='" . strftime ('%Y/%m/%d %H:%M:%S', localtime ())) .
		"' agent_name='" . $Conf{'agent_name'} . "' timezone_offset='". $Conf{'timezone_offset'}; 
	
	if (defined ($Conf{'parent_agent_name'})) {
		$Xml .= "' parent_agent_name='" .$Conf{'parent_agent_name'};
	}
	if (defined ($Conf{'longitude'}) && defined ($Conf{'latitude'})) {
		$Xml .= "' longitude='" .$Conf{'longitude'} . "' latitude='" .$Conf{'latitude'};
		if (defined ($Conf{'altitude'})) {
			$Xml .= "' altitude='" .$Conf{'altitude'};
		}
		if (defined ($Conf{'position_description'})) {
			$Xml .= "' position_description='" .$Conf{'position_description'};
		}
	}
	$Xml .= "'>\n";

	# Execute modules
	foreach my $module (@Modules) {

		# Execute the module in a separate thread
		if (defined ($ThreadSem) && $Conf{'agent_threads'} > 1) {
			$ThreadSem->down ();
			my $thr = threads->create (\&exec_module, $module);
			if (! defined ($thr)) {
				$ThreadSem->up ();
			} else {
				$thr->detach();
			}
		# Execute the module
		} else {
			exec_module ($module);
		}
	}

	# Execute plugins
	foreach my $plugin (@Plugins) {

		# Execute the plugin in a separate thread
		if (defined ($ThreadSem) && $Conf{'agent_threads'} > 1) {
			$ThreadSem->down ();
			my $thr = threads->create (\&exec_plugin, $plugin);
			if (! defined ($thr)) {
				$ThreadSem->up ();
			} else {
				$thr->detach();
			}
		# Execute the plugin
		} else {
			exec_plugin ($plugin);
		}
	}

	# Wait for all the threads
	$ThreadSem->down ($Conf{'agent_threads'}) if (defined ($ThreadSem) && $Conf{'agent_threads'} > 1);
	$ThreadSem->up ($Conf{'agent_threads'}) if (defined ($ThreadSem) && $Conf{'agent_threads'} > 1);
	
	$Xml .= "</agent_data>";

	# Save XML data file
	my $temp_file = $Conf{'temporal'} . '/' . $Conf{'agent_name'} . '.' . time () . '.data';
	open (TEMP_FILE, "> $temp_file") || error ("Could not write XML data file: $!");
	print TEMP_FILE $Xml;
	close (TEMP_FILE);

	# Debug mode
	if ($Conf{'debug'} eq '1') {
		log_message ('debug', "Wrote XML data file '$temp_file'");
		log_message ('debug', "Wrote XML data file '$temp_file'", *STDOUT);
		last;
	}

	# Send the XML data file
	send_file ($temp_file, 1);
	unlink ($temp_file);
	
	# Cron mode
	last if ($Conf{'cron_mode'} == 1);
	
	# Enable signal capture to break the Sleep interval on UDP signal
	if ($Conf{'udp_server'} == 1){
		$SIG{'INT'} = \&udp_server_signal;
	}

	# Go to sleep
	#
	sleep ($Conf{'interval'});
}


__END__

=head1 EXIT STATUS

=over 

=item 0 on Success

=item 1 on Error

=back 

=head1 CONFIGURATION

By default pandora_agent uses F</etc/pandora> as B<home configuration directory>. There is the F<pandora_agent.conf> file with all the configuration of the agent.

=head1 DEPENDENCIES


=head1 LICENSE

This is released under the GNU Lesser General Public License.

=head1 SEE ALSO


=head1 COPYRIGHT

Copyright (c) 2005-2010 Artica Soluciones Tecnologicas S.L

=cut