#!/usr/bin/perl -w

use strict;

use File::Basename;
use POSIX 'strftime';
use Sys::Syslog;

sub logit($);

logit('starting up');

my $cron_cmd = 'crontab -l';

while ( 1 ) {
  my $now   = strftime('%H%M', localtime);
  my $today = strftime('%w', localtime);

  for ( qx/$cron_cmd/ ) {
    if ( /^([\d*]+)\s+([\d*]+)\s+([\d*]+)\s+([\d*]+)\s+([\d\-*]+)\s+(.*)/ ) {
      my ( $min, $hour, $day, $mon, $dow, $cmd ) = ( $1, $2, $3, $4, $5, $6 );
      my $pattern;

      if ( $dow =~ m/\-/ ) {
        $pattern = "[$dow]";
      } elsif ( $dow =~ m/,/ ) {
        $dow =~ s/,//;
        $pattern = "[$dow]";
      } elsif ( $dow =~ m/^\d$/ ) {
        $pattern = "^$dow";
      } else {
        $pattern = ".*";
      }

      next unless $today =~ qr/$pattern/;

      if ( $cmd =~ m#(/etc/init.d/[^\s]+)\s+(start|stop)# ) {
        my ( $init, $mode ) = ( $1, $2 );
        if ( $mode eq 'start' ) {
          $schedule{$init}{start} = "$hour$min";
        } else {
          $schedule{$init}{stop}  = "$hour$min";
        }
      }
    }
  }
  for ( keys %schedule ) {
    if ( $now > $schedule{$_}{start} && $now < $schedule{$_}{stop} ) {
      if ( system("$_ status >/dev/null") ) {
        if ( $schedule{$_}{status} ne 'FAIL' || !$schedule{$_}{status} ) {
          logit("$_ isnt running");
          $schedule{$_}{status} = 'FAIL';
        }
      } else {
          if ( defined $schedule{$_}{status} && $schedule{$_}{status} eq 'FAIL' ) {
            logit("$_ is back to normal");
          }
          $schedule{$_}{status} = 'OK';
      }
    }
  }
  sleep 5;
}
logit('shutting down');

sub logit($) {
  my $msg = shift;
  openlog(basename($0), '', 'LOG_DAEMON');
  syslog('info', $msg);
  closelog();
}

##</code><code>##

00 05 * * 0 /etc/init.d/foo start
00 22 * * 0 /etc/init.d/foo stop

##</code><code>##

00 05 * * 1-5 /etc/init.d/foo2 start
00 22 * * 1-5 /etc/init.d/foo2 stop