#!/usr/bin/perl # ************************************************************** # * # * CHECK_MAIL_LOOP_DELAY # * # * Program: Linux plugin for Nagios # * License: GPL # * Copyright (c) 2014 - By Victor Ruiz Rivas (vruiz@adif.es) # * # * Description: # * # * This script is an hybrid of active and passive check plugin. # * It forks to run a child process which submits final results # * of the mail loop as passive check through Nagios command file. # * # * First the parent process sends a probe message connecting to an # * MTA server without client authentication and returns immediately # * to Nagios with the same service state it was given at command # * line and notifying of the message sent and its timestamp. # * # * The child process detaches from parent process and sleeps for a # * warning threshold period of time. It then awakes and connects # * to the mail box server to receive the probe message sent by # * the parent process and to delete it if it founds it. Otherwise it # * sleeps again until critical threshold and retries connection # * and deletion again, submitting results before exiting. # * # * Based on the found (or missing) probe within (out of) # * thresholds, Nagios is notified with "OK" if probe is found after # * the first connection, "WARNING" if found after the second or # * "CRITICAL" if not found. Also it is informed of possible delayed # * messages arrived from previous executions of the plugin. # * # * # * Nagios main config file options affecting this plugin: # * # * - accept_passive_service_checks=1 # * - check_external_commands=1 # * - command_file= # * # * Service definition directives suggested for this plugin: # * # * - command_check_interval gt (warning + critical thresholds)[s] # * - max_check_attempts=1 # * # * Possible usage in Nagios check command definition: # * # * command_line $USER1$/check_mail_loop_delay.pl -H "$HOSTNAME$" \ # * -D "$SERVICEDESC$" -S "$SERVICESTATEID$" \ # * -A "$ARG1$" -M "$ARG2$" -F "$ARG3$" -T "$ARG4$" \ # * -P "$ARG5$" -u "$ARG6$" -p "$ARG7$" -w "$ARG8$" \ # * -c "$ARG9" -f "$ARG10$" # * # * # * License Information: # * # * 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. # * # * $Id: check_mail_loop_delay.pl # * # *********************************************************************** use strict; use warnings; use Mail::Sender; use Net::IMAP::Simple; use Mail::POP3Client; use Getopt::Long qw( :config posix_default bundling no_ignore_case ); use Time::HiRes qw(time); use Fcntl qw(:flock); use POSIX qw(setsid strftime); use constant { true => 1, false => 0 }; ######## GLOBAL VARS & DEFAULTS ################################# use vars qw( $help $hostname $servicestateid $servicedesc $serviceoutput $mta_server $mail_server $timestamp $user_account $pid $tip $user_password $mail_from $mail_to $warning_threshold $critical_threshold %ERRORS $mail_protocol $subject $timeout $delayeds $receive_message $nagios_cmd_file ); # Adjust thresholds to your servers work load $warning_threshold = 120; # default 2 minutes warning threshold for receiving messages $critical_threshold = 420; # default 7 minutes critical threshold for receiving messages $timeout = 30; # default mta & mail servers response timeout $subject = "mail loop test"; # default header subject and body message substring $timestamp = get_time(); # timestamp signature to label message header's subject # Return codes for Nagios %ERRORS=('OK'=>0,'WARNING'=>1,'CRITICAL'=>2,'UNKNOWN'=>3,'DEPENDENT'=>4); ######## GET CLI ARGUMENTS & Nagios MACROS #################### GetOptions( "h|help" => \$help, "H|host_name=s" => \$hostname, # Nagios $HOSTNAME$ macro value "D|svc_descr=s" => \$servicedesc, # Nagios $SERVICEDESCR$ macro value "S|svc_state=i" => \$servicestateid, # Nagios last check $SERVICESTATEID$ macro value "A|mta_srv=s" => \$mta_server, # smtp server for sending messages "M|mail_srv=s" => \$mail_server, # imap or pop3 mail server "F|mail_from=s" => \$mail_from, # MAIL from: sender account "T|mail_to=s" => \$mail_to, # RCPT to: recipient account "P|prot=s" => \$mail_protocol, # protocol to use: pop3 or imap "u|user=s" => \$user_account, # mail account user "p|passwd=s" => \$user_password, # mail account password "w|warn:i" => \$warning_threshold, # optional loop warning time(seconds) threshold "c|crit:i" => \$critical_threshold, # optional loop critical time(seconds) threshold "s|subject:s" => \$subject, # optional subject string "f|cmd_file=s" => \$nagios_cmd_file, # Nagios command file for passive check submission "t|timeout:i" => \$timeout # optional timeout for connecting to servers ) or die("Error in command line arguments: $!\n"); usage() unless check_options(); ###################################################################################### ###################### SINGLE NAGIOS SERVICE CHECK INSTANCE RUNNING ################ # Due to the hybrid nature of this plugin running two paired processes (parent:send, # child:receive),for some check intervals and thresholds, Nagios plugin execution # could reach certain running conditions in which more than one plugin instance for # the same service check could be running concurrently. Therefore to prevent deletion # of probe messages sent for a different instance of the same service check that could # yield distorted results we should avoid concurrency at the service checks. In doing # so we refrain ourselves from checking more than one mail loop, but, should you ever # need to check different mail loops I suggest to comment out the next "flock" and the # final "__DATA__" blocks and define safe service check intervals and thresholds for # the services as suggested above, or just create a copy of this script and rename it # for each account/loop to test. unless (flock(DATA, LOCK_EX|LOCK_NB)){ # One instance already running, exit and warn Nagios return_to_nagios(" (*) can't flock $0: another plugin instance may be running! $!\n", $ERRORS{'WARNING'}); } ########################################################### ########################################################### ################## CHECK MAIL LOOP ######################## # System will reap automatically orphan child processes $SIG{CHLD} = 'IGNORE'; # flush buffers before forking and detach $| = 1; defined ( $pid = fork()) or # could not fork return_to_nagios("fork error: $!\n", $ERRORS{'UNKNOWN'}); if ($pid) { # I'm the parent send_probe_message(); return_to_nagios("message sent to $user_account with $mta_server at $timestamp\n", $servicestateid); }else{ # Detach child process setsid() or die "setsid can't start a new session: $!\n"; open STDIN, "< /dev/null" or die "can't read /dev/null: $!\n"; open STDOUT, ">> /dev/null" or die "can't write /dev/null: $!\n"; open STDERR, ">> /dev/null" or die "can't write /dev/null: $!\n"; open (CMDFILE, ">> $nagios_cmd_file") or die "can't open $nagios_cmd_file: $!\n" } # SECOND PART OF THE MAIL LOOP: retrieve, delete messages # and submit results to Nagios. # Set proper mail protocol retrieving function reference if ( $mail_protocol eq "pop3" ) { $receive_message = \&receive_pop3_message; }else{ $receive_message = \&receive_imap_message; } # First sleep for warning threshold wait sleep($warning_threshold); if ( $receive_message->() ) { $serviceoutput = "OK: mail message sent to '$mail_to' with MTA '$mta_server' server, received in '$mail_server' server in less than $warning_threshold seconds since $timestamp"; $servicestateid = $ERRORS{'OK'}; }else{ # Second sleep for critical threshold wait sleep($critical_threshold - $warning_threshold); if ( $receive_message->() ) { $serviceoutput = "WARNING: mail message sent to '$mail_to'<\/b> with MTA '$mta_server'<\/b> server, received in '$mail_server'<\/b> server, took more than $warning_threshold<\/b> and less than $critical_threshold<\/b> seconds since $timestamp<\/b>"; $servicestateid = $ERRORS{'WARNING'}; }else{ $serviceoutput = "CRITICAL: mail message sent to '$mail_to'<\/b> with MTA '$mta_server'<\/b> server not yet received in '$mail_server'<\/b> server after $critical_threshold<\/b> seconds elapsed since $timestamp<\/b>"; $servicestateid = $ERRORS{'CRITICAL'}; }; }; if ($delayeds > 0) { $serviceoutput = "$serviceoutput - received $delayeds<\/b> delayed message(s)"; }; submit_to_nagios($serviceoutput, $servicestateid); ################ END MAIL LOOP CHECK ###################### ########################################################### ########################################################### ########################################################### ########################################################### ################## FUNCTIONS ############################## # Sends probe message (from the parent process) sub send_probe_message { my $s = $subject." ".$timestamp; my $sender = new Mail::Sender{ smtp => $mta_server, from => $mail_from, to => $mail_to, subject => $s, timeout => $timeout, on_errors => undef }; unless ( ref $sender ) { return_to_nagios("error creating mail sender object: $!\n", $ERRORS{'CRITICAL'}); } $sender->Open() or return_to_nagios("error opening message to $mta_server: $!\n", $ERRORS{'CRITICAL'}); $sender->SendLineEnc($s) or return_to_nagios("error writing message to $mta_server: $!\n", $ERRORS{'CRITICAL'}); $sender->Close() or return_to_nagios("error closing and sending message to $mta_server: $!\n", $ERRORS{'CRITICAL'}); } ##################################### # Receives and deletes sent probe message(s) from imap server user inbox folder sub receive_imap_message { $delayeds = 0; my $received = false; # Create the imap client object my $imap = Net::IMAP::Simple->new( $mail_server ) || submit_to_nagios("Unable to establish connection to $mail_server server: $!\n", $ERRORS{'CRITICAL'}); # Log on if( ! $imap->login( $user_account, $user_password ) ){ submit_to_nagios("Login $user_account user to $mail_server failed: $imap->errstr\n", $ERRORS{'CRITICAL'}); } my $total_msgs = $imap->select('INBOX'); # examine each message for(my $i = 1; $i <= $total_msgs; $i++){ # process each message header line until Subject match foreach( $imap->top( $i ) ) { if ( /^Subject:\s+$subject/i ) { if ( /^Subject:\s+$subject\s+$timestamp/ ) { # this message was sent by the parent of this process $received = true; }else{ # this maybe a delayed message fom other process $delayeds ++; } $imap->delete($i); last; # go for next message }; }; }; $imap->quit(); return($received); }; ##################################### # Receives and deletes sent probe message(s) from pop3 server sub receive_pop3_message { $delayeds = 0; my $received = false; my $pop = new Mail::POP3Client( USER => $user_account, PASSWORD => $user_password, HOST => $mail_server ); if ( $pop->Count() == -1 ) { # There was an error trying to connect to POP3 server submit_to_nagios("Unable to establish connection to $mail_server server: $!\n", $ERRORS{'CRITICAL'}); } # examine each message for( my $i = 1; $i <= $pop->Count(); $i++ ) { # process each message header line until Subject match foreach( $pop->Head( $i ) ) { if ( /^Subject:\s+$subject/i ) { if ( /^Subject:\s+$subject\s+$timestamp/ ) { # this message was sent by the parent of this process $received = true; }else{ # this maybe a delayed message fom other process $delayeds ++; } $pop->Delete($i); last; # go for next message }; }; }; $pop->Close(); return($received); }; ##################################### # Check options received through command line sub check_options { my $ret = false; if ( $help ){ $tip = "(*) usage ..."; }elsif ( not $critical_threshold > $warning_threshold ){ $tip = "(*) critical threshold must be greater than warning threshold ..."; }elsif( !$hostname or !$servicedesc or ! defined $servicestateid ){ $tip = "(*) missing some Nagios MACRO(s) argument(s) ..."; }elsif( !$mta_server or !$mail_server ){ $tip = "(*) missing mta and/or mail server(s) ..."; }elsif( !$mail_from or !$mail_to ){ $tip = "(*) missing mail_from and/or mail_to argument(s) ..."; }elsif( !$mail_protocol or ( $mail_protocol ne "pop3" and $mail_protocol ne "imap") ){ $tip = "(*) missing or unknown mail protocol (pop3|imap) argument ..."; }elsif( !$user_account or !$user_password ){ $tip = "(*) missing mail user account credentials ..."; }elsif( !$nagios_cmd_file ){ $tip = "(*) missing nagios command file argument ..."; }else{ $ret = true; }; return $ret; } ###################################### # Return to Nagios (only from parent process) sub return_to_nagios { my($plugin_output, $return_code) = @_; print $plugin_output; exit($return_code); }; ##################################### # Write service output to Nagios command file (only from child process) sub submit_to_nagios { my ( $plugin_output, $return_code ) = @_; my $submit_time = time; my $cmd_line = "[".$submit_time."] PROCESS_SERVICE_CHECK_RESULT;".$hostname.";".$servicedesc.";".$return_code.";".$plugin_output; print CMDFILE $cmd_line; close(CMDFILE); exit($return_code); }; ##################################### # Get human readable timestamp sub get_time { my $unix_time = time; my $date = strftime "%Y-%m-%d %H:%M:%S", localtime($unix_time); $date .= sprintf ".%05d", ($unix_time-int($unix_time))*100000; return $date; }; ##################################### sub usage { print < -D <\$SERVICEDESC\$> -S <\$SERVICESTATEID\$> -A -M -F -T -P -u -p -w -c -s
-f -t -h|--help prints this help -H|--host_name Nagios host name macro \$HOSTNAME\$ expected -D|--svc_descr Nagios service description macro \$SERVICEDESC\$ expected -S|--svc_state Nagios service state ID macro \$SERVICESTATEID\$ expected -A|--mta_srv smtp server FQDN or IP address -M|--mail_srv mail server FQDN or IP address -F|--mail_from MAIL from: sender account -T|--mail_to RCPT to: recipient account -P|--prot imap or pop3 mail server protocol -u|--user mail account user -p|--passwd mail account password -w|--warn optional warning time(seconds) threshold -c|--crit optional critical time(seconds) threshold -s|--subject optional subject string -f|cmd_file Nagios command file for passive check result submission -t|timeout optional timeout(seconds) for mta & mail servers response EOH exit($ERRORS{'WARNING'}); } __DATA__ This exists so flock() code above works. DO NOT REMOVE THIS DATA SECTION.