#!/usr/bin/perl
# Host(s) Monitor (using fping)


#### Pagefile Usage ###########
#
# hostname:pagelist
#
# Example:
# goliath:steve@yahoo.com,mike@yahoo.com
# hercules:steve@yahoo.com,sarah@yahoo.com
#
###############################

#-----------------------------------------------------------
# Environment Variables                                    |
#-----------------------------------------------------------
$pagefile="pagelist";   # Config file for hostname:pagelist
$default_mail="root";
$timeout=90000;         # Adjusts Sensitivity Level for Network traffic(milliseconds)
$fping="/usr/local/bin/fping";
$count=0;
$cnt=0;
$lines=0;
$check=0;
#-------------------------------------------------------------

#-------------------------------------------------------------
# Logging Options                                            |
#-------------------------------------------------------------
$log="hostlog";
$response_times="response_times";
$outages="outages";
#-------------------------------------------------------------

#-------------------------------------------------------------
# Required Perl Modules                                      |
#-------------------------------------------------------------
require Mail::Send;      # From Mail::Tools
#-------------------------------------------------------------

#-------------------------------------------------------------
# Make or notify user of required files                      |
#-------------------------------------------------------------
if ( ! -e $response_times ){
`touch $response_times`;
}

if ( ! -e $log ){
`touch $log`;
}
#--------------------------------------------------------------


#--------------------------------------------------------------
# Verify integrity of config file - loosely                   |
#--------------------------------------------------------------
open(FILE1, "<$pagefile") || die "Cannot find $pagefile\n";

while (<FILE1>){
 
        @letters= split(//);
        {
          $lines=$lines+1;

                foreach (@letters){
                        if(/:/){
                        $cnt=$cnt+1
                        }
                }
        }
}
                if ($lines ne $cnt){
                print("Error in config file\n");
                exit;
                }
close (FILE1);
#---------------------------------------------------------------

# Start

while (1){

        open(FILE1, "<$pagefile") || die "Cannot open $pagefile\n";

        while (<FILE1>){ 

        @data = split(/:/, $_);
        $hostname=@data[0];
        $mailto=@data[1];

        $mailstrl = length($mailto);

        if ( $mailstrl < 1 ){
        
                $mailto="$default_mail";
                chomp($mailto, $hostname);
                }

        foreach ($hostname){
        
        $date=localtime(time);
        $check = `$fping -e -r 10 -t $timeout $hostname`;
 
        open(RESPONSE,">>$response_times");
        print RESPONSE "$date $check";
        close(RESPONSE);

          if ( $check =~ /unreachable|down|not found/i ){
           
                $machine {"$hostname"}++;

                if ($machine {"$hostname"} == 1){

                open(RESPONSE,">>$outages");
                print RESPONSE "$hostname went down at $date\n";
                close(RESPONSE);

                $msg=new Mail::Send Subject=>"$hostname went down at $date", 
                To=>"$mailto";
                $fh=$msg->open;
                $fh->close;

                open(LOG,">> $log");
                print LOG "$hostname went down at $date\n";
                close(LOG);
                }
           }
        }

sleep 30;

# Are we still down? Only send page if host is now alive
# Send only one page, log to file
 
        foreach ($hostname){
        
           if ($machine {"$hostname"} >= 1){
           
           $date=localtime(time);
           $check2 = `$fping -e -r 10 -t $timeout $hostname`; 

                if ( $check2 =~ /alive/i ){

                open(RESPONSE,">>$outages");
                print RESPONSE "$hostname alive at $date\n";
                close(RESPONSE);

                $msg=new Mail::Send Subject=>"$hostname alive at $date",
                To=>"$mailto";
                $fh=$msg->open;
                $fh->close;

                open(LOG,">> $log");
                print LOG "$hostname alive at $date\n";
                close(LOG);

                $machine{"$hostname"}=0;
                }
       }
    }
  }
}