contrib/scripts/nanny.pl

#!/usr/bin/perl
#
# Copyright (C) 2000, 2001, 2004, 2007, 2012, 2014, 2016  Internet Systems Consortium, Inc. ("ISC")
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# $Id: nanny.pl,v 1.11 2007/06/19 23:47:07 tbox Exp $

# A simple nanny to make sure named stays running.

$pid_file_location = '/var/run/named.pid';
$nameserver_location = 'localhost';
$dig_program = 'dig';
$named_program =  'named';

fork() && exit();

for (;;) {
    $pid = 0;
    open(FILE, $pid_file_location) || goto restart;
    $pid = <FILE>;
    close(FILE);
    chomp($pid);

    $res = kill 0, $pid;

    goto restart if ($res == 0);

    $dig_command =
           "$dig_program +short . \@$nameserver_location > /dev/null";
    $return = system($dig_command);
    goto restart if ($return == 9);

    sleep 30;
    next;

 restart:
    if ($pid != 0) {
        kill 15, $pid;
        sleep 30;
    }
    system ($named_program);
    sleep 120;
}