#!/usr/bin/perl -T
#
# Tail the httpd access log file and change the pxelinux.cfg link so that
# the host doesn't do multiple installs
# Harry Hoffman <hhoffman@ip-solutions.net
#
use warnings; #Make use of lexical warnings as opposed to the -w flag
use strict; #Make sure to pre-declare all variables
delete @ENV{qw{IFS PATH CDPATH ENV BASH_ENV}}; #remove potential nasties
$ENV{PATH} = '/bin:/usr/bin'; #Always set the path (never use ./)

use File::Tail;

my $httpdlog = "/var/log/httpd/access_log";
my $pxecfgdir = "/tftpboot/kernel/linux/pxelinux.cfg";
my $localboot = "default";

my $pid = fork();
if ($pid)
{
  exit();
}
  else
{
  my $file = File::Tail->new(name=>$httpdlog,maxinterval=>5,adjustafter=>3);
  while ( defined(my $line = $file->read) )
  {
     my $line =  "GET /Profiles/10.0.1.2-kickstart HTTP/1.0\" 200";
     if ($line =~ /.*\/(\d+\.\d+\.\d+\.\d+)-kickstart HTTP\/1\.0\" 200.*/)
     {
        my $ip = $1;
        my $hexip = dec2hex($ip);
        print "$hexip\n";
        chdir $pxecfgdir or die "unable to move into $pxecfgdir: $!\n";
        unlink $hexip;
        symlink($localboot,$hexip) or die "unable to create symlink: $!\n";
     }
  }
}

sub dec2hex
{
  my $ip=shift;
  my @matches = split(/\./,$ip);
  my $hexip = "";
  foreach (@matches)
  {
     $_ = sprintf("%02x",$_);
     $hexip = "$hexip" . "$_";
  }
  $hexip =~ tr/a-f/A-F/;
  return $hexip;
}