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      1 #!/usr/bin/perl
      2 #
      3 # Copyright (C) Internet Systems Consortium, Inc. ("ISC")
      4 #
      5 # SPDX-License-Identifier: MPL-2.0
      6 #
      7 # This Source Code Form is subject to the terms of the Mozilla Public
      8 # License, v. 2.0. If a copy of the MPL was not distributed with this
      9 # file, you can obtain one at https://mozilla.org/MPL/2.0/.
     10 #
     11 # See the COPYRIGHT file distributed with this work for additional
     12 # information regarding copyright ownership.
     13 
     14 # A simple nanny to make sure named stays running.
     15 
     16 $pid_file_location = '/var/run/named.pid';
     17 $nameserver_location = 'localhost';
     18 $dig_program = 'dig';
     19 $named_program =  'named';
     20 
     21 fork() && exit();
     22 
     23 for (;;) {
     24 	$pid = 0;
     25 	open(FILE, $pid_file_location) || goto restart;
     26 	$pid = <FILE>;
     27 	close(FILE);
     28 	chomp($pid);
     29 
     30 	$res = kill 0, $pid;
     31 
     32 	goto restart if ($res == 0);
     33 
     34 	$dig_command =
     35 	       "$dig_program +short . \@$nameserver_location > /dev/null";
     36 	$return = system($dig_command);
     37 	goto restart if ($return == 9);
     38 
     39 	sleep 30;
     40 	next;
     41 
     42  restart:
     43 	if ($pid != 0) {
     44 		kill 15, $pid;
     45 		sleep 30;
     46 	}
     47 	system ($named_program);
     48 	sleep 120;
     49 }
     50