#!/usr/bin/perl -w

############################## check_wrapper ################################################################################
#
# Name    : check_wrapper
# Version : 1.0
# Date    : Jan 31, 2012
# Author  : Anton Hofland
# Company : 2024Sight (www.2024sight.com)
# Licence : GPL - http://www.fsf.org/licenses/gpl.txt
#
# This plugin was developed to act like a wrapper around any other Nagios plugin. The objective of the wrapper is to create
# a capability to test the Nagios system in line and without having to make any changes to the system. The wrapper will
# check whether a plugin is in test mode. If it is, then it returns the pre-defined error code. The wrapper also decrements
# the test counter. Should the counter reach 0, the wrapper will reset the test mode. The next time the plugin is invoked it
# will execute normally. If the plugin is not in test mode, then wrapper will exec the plugin. The wrapper script assumes
# it is installed in the same location as the other plugins. It also assumes it will be invoked using an absolute path. The
# wrapper uses its own invokation path to create the path to the nagios plugin.
#
# Seperately, the wrapper can also syslog the invocation of a plugin. This will contnue until it is explicitely cancelled.
#
#############################################################################################################################

use strict;

use File::Basename;
use Sys::Syslog		qw( :DEFAULT setlogsock);

my $Version		= '1.0';

my $Command		= $0;
my $Path		= dirname( $Command );
my $Configuration_File	= "/var/lib/nagios/logs/check_wrapper";

my $O_Help		= undef;
my $O_Version		= undef;
my $O_Configure		= undef;
my $O_Count		= undef;
my $O_Error		= undef;
my $O_Reset		= undef;
my $O_Log		= undef;
my $O_NoLog		= undef;
my $O_Plugin		= undef;

my %Configuration;
my %Errors		=
			(	'OK'		=> 0,
				'WARNING'	=> 1,
				'CRITICAL'	=> 2,
				'UNKNOWN'	=> 3,
				'DEPENDENT'	=> 4
			);

#############################################################################################################################

sub print_version
{
	print "check_wrapper version : $Version\n";
}

#############################################################################################################################

sub print_usage
{
	print "Usage: check_wrapper --help\n";
	print "       check_wrapper --version\n";
	print "       check_wrapper [--file config file] --configure <nagios plugin> <error code> <counter>\n";
	print "       check_wrapper [--file config file] --reset     <nagios plugin>|all\n";
	print "       check_wrapper [--file config file] --log       <nagios plugin>\n";
	print "       check_wrapper [--file config file] --nolog     <nagios plugin>|all\n";
	print "       check_wrapper [--file config file]             <nagios plugin> [nagios plugin options]\n";
}

#############################################################################################################################

sub print_help
{
	my $Key	= undef;

  	print "\n";
	print "Nagios Plugin Wrapper to test the Nagios system by simulating a return code and by syslogging the invokation\n"; 
	print "\n";
	print_usage();
	print "\n";
	print "       --help         Print help message\n";
	print "       --version      Print version\n";
	print "       --configure    Configure the <nagios plugin> to return the <error code> the next <count> times\n";
	print "       --reset        Remove the configuration of the <error code> for the <nagios plugin> or all plugins\n";
	print "       --log          Enables logging to syslog of every invocation of the <nagios plugin> and arguments\n";
	print "       --nolog        Disables logging to syslog of <nagios plugin> or all plugins\n";
	print "       --file         Specify the path to the check_wrapper configuration file\n";
	print "\n";
	print "       Error Codes:   ";

	foreach $Key ( keys %Errors )
	{
		print "$Key ";
	}

	print "\n\n";
	print "                      The <counter> should be greater than zero.\n\n";
	print "                      If no check_wrapper options are specified, the wrapper checks whether the plugin is\n";
	print "                      in test mode. If it is then the wrapper will return the specifed return code. If it\n";
	print "                      not then the wrapper will execute the plugin with the remaining arguments. By\n";
	print "                      inserting a call to check_wrapper in the nagios configuration or nrpe.cfg nagios can\n";
	print "                      be instrumented with this test capability\n\n";
	print "                      The wrapper also accepts the old style command line options\n";
	print "\n\n";
	print "This module maintains a configuration file that has to be writable by the nagios system.\n";
	print "The full path is: $Configuration_File\n";
	print "\n\n";
	print "The Nagios check_wrapper plugin has been developed by 2024Sight (www.2024sight.com)\n";
	print "\n";
}

#############################################################################################################################

sub check_options
{
	if    (( defined( $ARGV[ 0 ] )) && ( $ARGV[ 0 ] =~ /^(--help|-h)$/      ))
	{
		$O_Help		= 1;
		shift @ARGV;
	}
	elsif (( defined( $ARGV[ 0 ] )) && ( $ARGV[ 0 ] =~ /^(--version|-v)$/   ))
	{
		$O_Version	= 1;
		shift @ARGV;

		if ( defined( $ARGV[ 0 ] ))
		{
			$O_Help	= 1;
		}
	}
	elsif (( defined( $ARGV[ 0 ] )) && ( $ARGV[ 0 ] =~ /^(--file|-f)$/ ))
	{
		shift @ARGV;

		if ( defined( $ARGV[ 0 ] ))
		{
			$Configuration_File	= $ARGV[ 0 ];
			shift @ARGV;
		}
		else
		{
			$O_Help	= 1;
		}
	}

	if (( defined( $ARGV[ 0 ] )) && ( $ARGV[ 0 ] =~ /^(--configure|-c)$/ ))
	{
		$O_Configure	= 1;
		shift @ARGV;

		if ( defined( $ARGV[ 0 ] ))
		{
			my $Pattern	= undef;
			my $Key		= undef;

			$O_Plugin	= $ARGV[ 0 ];
			shift @ARGV;

			foreach $Key ( keys %Errors )
			{
				if ( defined( $Pattern ))
				{
					$Pattern	= "$Pattern". "|" . $Key;
				}
				else
				{
					$Pattern	=  $Key;
				}
			}

			if (( defined( $ARGV[ 0 ] )) && ( $ARGV[ 0 ] =~ /^($Pattern)$/i ))
			{
				$O_Error	=  $ARGV[ 0];
				$O_Error	=~ tr/a-z/A-Z/;
				shift @ARGV;

				if (( defined( $ARGV[ 0 ] )) && ( $ARGV[ 0 ] =~ /^\d+$/ ))
				{
					$O_Count	= $ARGV[ 0 ];
					shift @ARGV;

					if (( $O_Count <= 0 ) || ( defined( $ARGV[ 0 ] )))
					{
						$O_Help	= 1;
					}
				}
				else
				{
					$O_Help	= 1;
				}
			}
			else
			{
				$O_Help	= 1;
			}
		}
		else
		{
			$O_Help	= 1;
		}
	}
	elsif (( defined( $ARGV[ 0 ] )) && ( $ARGV[ 0 ] =~ /^(--reset|-r)$/     ))
	{
		$O_Reset	= 1;
		shift @ARGV;

		if ( defined( $ARGV[ 0 ] ))
		{
			$O_Plugin	= $ARGV[ 0 ];
			shift @ARGV;

			if ( defined( $ARGV[ 0 ] ))
			{
				$O_Help	= 1;
			}
		}
		else
		{
			$O_Help	= 1;
		}
	}
	elsif (( defined( $ARGV[ 0 ] )) && ( $ARGV[ 0 ] =~ /^(--log|-l)$/     ))
	{
		$O_Log	= 1;
		shift @ARGV;

		if ( defined( $ARGV[ 0 ] ))
		{
			$O_Plugin	= $ARGV[ 0 ];
			shift @ARGV;

			if ( defined( $ARGV[ 0 ] ))
			{
				$O_Help	= 1;
			}
		}
		else
		{
			$O_Help	= 1;
		}
	}
	elsif (( defined( $ARGV[ 0 ] )) && ( $ARGV[ 0 ] =~ /^(--nolog|-n)$/     ))
	{
		$O_NoLog	= 1;
		shift @ARGV;

		if ( defined( $ARGV[ 0 ] ))
		{
			$O_Plugin	= $ARGV[ 0 ];
			shift @ARGV;

			if ( defined( $ARGV[ 0 ] ))
			{
				$O_Help	= 1;
			}
		}
		else
		{
			$O_Help	= 1;
		}
	}
	elsif (( defined( $ARGV[ 0 ] )) && ( ! ( $ARGV[ 0 ] =~ /^-+/ )))
	{
		$O_Plugin	= $ARGV[ 0 ];
		shift @ARGV;
	}
	else
	{
		$O_Help = 1;
	}
}

#############################################################################################################################

sub load_configuration
{
	my $Plug_In	= undef;
	my $Log		= undef;
	my $Error	= undef;
	my $Count	= undef;
	my $Line	= undef;

	if ( open( CONFIG, "$Configuration_File" ))
	{
		while ( $Line = <CONFIG> )
		{
			chomp( $Line );

			if ( ! ( $Line =~ /^#/ ))
			{
				( $Plug_In, $Log, $Error, $Count )	= split( /;/, $Line );
				$Configuration{ $Plug_In }		= $Log . ";" . $Error . ";" . $Count;
			}
		}

		close( CONFIG );
	}
}

#############################################################################################################################

sub save_configuration
{
	my $Plug_In	= undef;
	my $Log		= undef;
	my $Error	= undef;
	my $Count	= undef;

	if ( open( CONFIG, ">$Configuration_File" ))
	{
		print CONFIG "# check_wrapper configuration file\n";

		foreach $Plug_In ( keys %Configuration )
		{
			( $Log, $Error, $Count )	= split( /;/, $Configuration{ $Plug_In } );

			if (( $Count > 0 ) || ( $Log =~ /^log$/ ))
			{
				print CONFIG "$Plug_In;$Configuration{ $Plug_In }\n";
			}
		}

		close( CONFIG );
	}
	else
	{
		print "check_wrapper: could not open configuration file $Configuration_File\n";
		exit $Errors{ "UNKNOWN" };
	}
}

################################### MAIN ####################################################################################
#
# The main program starts here. The first thing is to read the options.
#
#############################################################################################################################

check_options();

if    ( defined( $O_Version ))
{
	print_version();
	exit $Errors{ "UNKNOWN" };
}
elsif ( defined( $O_Help ))
{
	print_help();
	exit $Errors{ "UNKNOWN" };
}

load_configuration();

if    ( defined( $O_Configure ))
{
	my $Log		= "nolog";
	my $Error	= undef;
	my $Count	= undef;

	if ( defined( $Configuration{ $O_Plugin } ))
	{
		( $Log, $Error, $Count ) = split( /;/, $Configuration{ $O_Plugin } );
	}

	$Configuration{ $O_Plugin }	= $Log . ";" . $O_Error . ";" . $O_Count;
	save_configuration();

	exit $Errors{ "UNKNOWN" };
}
elsif ( defined( $O_Reset ))
{
	my $Log		= "nolog";
	my $Error	= undef;
	my $Count	= undef;

	if ( $O_Plugin =~ /^all$/i )
	{
		my $Key	= undef;

		foreach $Key ( keys %Configuration )
		{
			( $Log, $Error, $Count )	= split( /;/, $Configuration{ $O_Plugin } );
			$Configuration{ $Key }		= $Log . ";OK;0";
		}
	}
	else
	{
		if ( defined( $Configuration{ $O_Plugin } ))
		{
			( $Log, $Error, $Count )	= split( /;/, $Configuration{ $O_Plugin } );
		}

		$Configuration{ $O_Plugin }	= $Log . ";OK;0";
	}
	save_configuration();

	exit $Errors{ "UNKNOWN" };
}
elsif ( defined( $O_Log ))
{
	my $Log		= undef;
	my $Error	= "OK";
	my $Count	= 0;

	if ( defined( $Configuration{ $O_Plugin } ))
	{
		( $Log, $Error, $Count ) = split( /;/, $Configuration{ $O_Plugin } );
	}

	$Configuration{ $O_Plugin }	= "log;" . $Error . ";" . $Count;
	save_configuration();

	exit $Errors{ "UNKNOWN" };
}
elsif ( defined( $O_NoLog ))
{
	my $Log		= "undef";
	my $Error	= "OK";
	my $Count	= 0;

	if ( $O_Plugin =~ /^all$/i )
	{
		my $Key	= undef;

		foreach $Key ( keys %Configuration )
		{
			( $Log, $Error, $Count )	= split( /;/, $Configuration{ $Key } );
			$Configuration{ $Key }		= "nolog;" . $Error . ";" . $Count;
		}
	}
	else
	{
		if ( defined( $Configuration{ $O_Plugin } ))
		{
			( $Log, $Error, $Count )	= split( /;/, $Configuration{ $O_Plugin } );
		}

		$Configuration{ $O_Plugin }	= "nolog;" . $Error . ";" . $Count;
	}
	save_configuration();

	exit $Errors{ "UNKNOWN" };
}

if ( defined( $Configuration{ $O_Plugin } ))
{
	my $Log		= undef;
	my $Count	= undef;
	my $Error	= undef;

	( $Log, $Error, $Count ) = split( /;/, $Configuration{ $O_Plugin } );

	if ( $Log =~ /^log$/ )
	{
    		my $user	= $ENV{'USER'};
		my $Argument	= undef;
		my $Arguments	= undef;

		foreach $Argument( @ARGV )
		{
			if ( defined( $Arguments ))
			{
				$Arguments	= $Arguments . " " . $Argument;
			}
			else
			{
				$Arguments	= $Argument;
			}
		}

		if  ( ! defined( $Arguments ))
		{
			$Arguments	= "No arguments provided";
		}

    		setlogsock( 'unix' );
    		openlog(    $O_Plugin,'','user');

    		syslog( 'debug', "$Arguments" );

    		closelog;
	}

	if ( $Count > 0 )
	{
		$Count                      = $Count - 1;
		$Configuration{ $O_Plugin } = $Log . ";" . $Error . ";" . $Count;
		save_configuration();

		print "$O_Plugin: check_wrapper simulated return code $Error ($Count)\n";
		exit $Errors{ $Error };
	}
	else
	{
		save_configuration();
	}
}

$Command	= $Path . '/' . $O_Plugin;

if ( -x $Command )
{
	exec $Command, @ARGV;
}

print "check_wrapper: could not execute $Command\n";
exit $Errors{ "CRITICAL" };

#############################################################################################################################