#!/usr/bin/perl -w
#
# NTP time server watchdog script

use strict;

# Get name of this computer
my $host = `hostname`;
chomp $host;

# Name of file for tracking state
my $tmpfile = '/tmp/ntp-watcher-already-complained';

# Make sure ntpd is running
my @ps_grep = `ps ax|grep ntpd|grep -v grep`;
if (@ps_grep != 1) {
	print "$host: NTP daemon is not running!\n" unless -e $tmpfile;
	system "touch $tmpfile";
	exit;
}

# Get status of the server via ntpdc
my @status = `ntpdc -c pe`;

# Check for PPS peer being locked
my $pps_found = 0;
foreach (@status) {
	$pps_found = 1 if /\*PPS/o;
}

# Error if PPS lock not found
if (not $pps_found) {
	print "$host: PPS synchronization lost!\n" unless -e $tmpfile;
	system "touch $tmpfile";
	exit;
}

# Clean up state tracking file
system "rm $tmpfile" if -e $tmpfile;