#!/usr/bin/perl -w
# -*- perl -*-

=head1 NAME

snmp__users - Plugin to check the number of logged in users via SNMP

=head1 CONFIGURATION

The following environment variables are used
 host      - SNMP host to use (default undef)
 port      - SNMP port to use (default 161)
 community - SNMP community string to use (default "public")
 interface - (default undef)

The host name is taken from the symlink name if the plugin snmp__users
is linked as snmp_hostname_users

=head1 AUTHOR

Copyright (C) 2004 Jimmy Olsen, Dagfinn Ilmari Mannsaaker

=head1 LICENSE

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 dated June,
1991.

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.

=head1 MAGIC MARKERS

 #%# family=snmpauto
 #%# capabilities=snmpconf

=head1 BUGS

The "interface" environment variable does not seem to be used.

=cut

use strict;
use Net::SNMP;

my $DEBUG = 0;
my $MAXLABEL = 20;

my $host      = $ENV{host}      || undef;
my $port      = $ENV{port}      || 161;
my $community = $ENV{community} || "public";
my $iface     = $ENV{interface} || undef;

my $response;

if (defined $ARGV[0] and $ARGV[0] eq "snmpconf")
{
	print "require 1.3.6.1.2.1.25.1.5.0 [0-9]\n"; # Number
	exit 0;
}

if ($0 =~ /^(?:|.*\/)snmp_([^_]+)_users$/)
{
	$host  = $1;
	if ($host =~ /^([^:]+):(\d+)$/)
	{
		$host = $1;
		$port = $2;
	}
}
elsif (!defined($host))
{
	print "# Debug: $0 -- $1\n" if $DEBUG;
	die "# Error: couldn't understand what I'm supposed to monitor.";
}

my ($session, $error) = Net::SNMP->session(
		-hostname  => $host,
		-community => $community,
		-port      => $port
	);

if (!defined ($session))
{
	die "Croaking: $error";
}

if (defined $ARGV[0] and $ARGV[0] eq "config")
{
	print "host_name $host\n" unless $host eq 'localhost';
	print "graph_title Number of users
graph_args --base 1000 -l 0 
graph_vlabel number of users
graph_scale no
graph_category system
graph_info This graph shows the number of users currently in to the system.
users.label users
users.draw LINE2
users.info Number of users logged in.
";

	exit 0;
}

print "users.value ", &get_single ($session, "1.3.6.1.2.1.25.1.5.0"), "\n";

sub get_single
{
	my $handle = shift;
	my $oid    = shift;

	print "# Getting single $oid...\n" if $DEBUG;

	$response = $handle->get_request ($oid);

	if (!defined $response->{$oid})
	{
	    return undef;
	}
	else
	{
	    return $response->{$oid};
	}
}