#!/usr/bin/perl
use strict;
use Net::Ping;
use Mail::Send;

die "Usage: svcheck <hosts> <emails>\n\n" unless defined ($ARGV[0]);

my @email;	# Array of email addresses from command line
my @ip;		# Array of hosts from command line (IP or hostname)


# Break down command args...
foreach my $arg (@ARGV) {
    if ($arg=~/(\S+@\S+)/) {
	push(@email, $arg);
    } else {
	push(@ip, $arg);
    }
}

my $time;
my @svcheck;
if ( -f "/tmp/time_svcheck" ) {
    open F, "/tmp/time_svcheck";
    @svcheck=<F>;
}


# Loop through hosts
my $ip;
my $last;
foreach $ip (@ip) {

    # Ping the host...
    my $p = Net::Ping->new("icmp", 6);
        my $ret=$p->ping($ip,6);
		$p->close();

    # If ping was unsuccessful, send mail to all email recipients.
    if (! $ret) {

	# Check to see if host is in /tmp/time_svcheck
	$last=0;
	foreach my $l (@svcheck) {
	    chomp $l;
	    if(!$last && $l =~ /^\d+$/) {
		$time=$l;
	    }
	    if ($ip eq $l) {
		$last=1;
	    }
	}

	print "Last: $last\nTime: $time\ntime: ", time, "\n";

	if ($last && time - $time < 1800) {
	    print $_=localtime(time), ": Throttling email output.\n";
	} else {

	    print $_=localtime(time), ": Host $ip is down?\n";
	    my $msg=new Mail::Send;
	    #$msg->to('kenw@cruzoid.com');
	    foreach my $to (@email) {
		$msg->to($msg->to, $to);
		print $_=localtime(time), ": Mailing $to\n";
	    }
	    $msg->subject("$ip: Host not responding to ping");
	    my $fh=$msg->open;

	    print $fh $_=localtime(time), ": $ip is down?";
	    $fh->close;  # Close fires off the email

	    push @svcheck, $ip;
	}

    } else {

	# Usually unnecessary output, but can be dumped into a log file or something...
	print $_=localtime(time), ": Host $ip is okay\n";

	# Remove host from /tmp/time_svcheck file
	my $i;
	my $l;
	for ($i=0; $i<=$#svcheck; $i++) {
	    $l=$svcheck[$i]; chomp($l);
	    if($l eq $ip) {
		splice(@svcheck, $i, 1);
	    }
	}
    }
}

open F, ">/tmp/time_svcheck";
print F time, "\n";
foreach my $l (@svcheck) {
    print F $l, "\n";
}
close F;