#!/usr/bin/perl 

# For Debugging purposes only!!
$DEBUG = 1;

@key_entries = ( "options", "controls", "zone \".\" IN", "zone \"localhost\"", "zone \"0.0.127.in-addr.arpa\"" );
@keep_zone_entries;
@keep_config_entries;

# Sub routine: removeHostsFile
# Passes     : String containing the record entry.
# Returns    : Nothing
# Description: removeHostsFile searches through the record looking for the path of the hosts file.
#              Once found it will remove the file.
sub removeHostsFile
{
	$test_entry = $_;
	
	if($DEBUG) { print("\nTest Entry: $_"); }
	
	$begin = index($test_entry, "file \"");
	$end = index($test_entry, "\";", $begin);
	$off = $begin + length("file \"");
	$len = ($end - $begin)-6;
	$hosts_file = substr($test_entry, $off, $len );
	
	if($DEBUG)
	{
		print "\nBegin: $begin";
		print "\nEnd: $end";
		print "\nOffset: $off";
		print "\nlength: $len"; 
		print "\n" . substr($test_entry, $off, $len );
		print "\n";
	}
		
	if($DEBUG) { print("\nRemoving $_\nand Deleteing: $hosts_file"); }
	system("rm -f $hosts_file");
}

# Sub routine: ProcessDNSRecord
# Passes     : String containing a domain name, Array containing the lines of the record entry for the domain (ie paulslinuxbox.net)
# Returns    : Nothing
# Description: Takes a string and then digs the domain name and dumps 
#              the output of dig into a file with the name of the domain it was diging for.
sub ProcessDNSRecord {
    my($d_name, $r_entry) = @_;    
    my($add_to_array) = 0;
      
    if( $DEBUG ) 
    {
    	print( "Domain Name: " . $d_name . "\nnamed.conf Entry:\n" . $r_entry . "\n-----------------------\n");
  		print( "Running: dig 169.207.1.3 " . $d_name . " >> ./temp/" . $d_name );
    }
    
    # Run the dig program and look up information on the domain name in $_
    system("dig 169.207.1.3 " . $d_name . " >> ./temp/" . $d_name );
     
    open(output_file, "./temp/$d_name");
    
    @array = <output_file>;
    
    close(output_file);
    
    if( $DEBUG ) 
    {
    	print("\nContents of temporary file:\n");
		foreach(@array) {
			print("CONTENTS: $_\n");
		}
    }
    
    # Read each line and look for the strings 'NS' and milwaukeepc.com
    foreach(@array) {
    	if( $DEBUG ) { 	print( $_ ); }
	
		if( index($_, "milwaukeepc.com") > 0) {
	    	if($DEBUG) { print("NS RECORD: \n$domain_name"); }
	    	if($DEBUG) { print("\nThis is being writen to the new file: \n$record_entry"); } 
	    	$add_to_array++;
		}
	}
    
    if( $add_to_array > 0) { 
    	if ($DEBUG) { print("\nrecord entry going into array: $record_entry"); }
    	push(@keep_zone_entries, $r_entry); 
    }
    
    if( $add_to_array <= 0 ) {
    	print("\nRecord Entry: $r_entry");
    }
}


# Sub routine: GetDomainName
# Passes     : String containing an entire zone entry
# Returns    : String containing a domain name (ie paulslinuxbox.net)
# Description: Takes a string that contains a zone record from the /etc/named.conf
sub GetDomainName 
{
	if($DEBUG) { print "\nGetDomainName passed $_")
    
	$i = index($_[0], "zone");
    
	if($DEBUG) { print "\nzone position: $i"; }
    
	if($i == 0) 
    {
    	@zone_array = split("\"", $_[0], 3);
	
		if( $DEBUG ) {  print("\nThe domain name that was extracted is: $zone_array[1]"); }
		
		if( ( $_ ne "." ) || ( index($_, "localhost") > 0 ) || ( index($_, "in-addr.arpa") > 0) )  
		{	    
	    	if($DEBUG) { print("\nI am going to be returning $zone_array[1]"); }
	    	return $zone_array[1];
		}
    } else {
		return "";
    }
}

# Sub routine: GetZoneEntriesOnly
# Passes     : Array containing all entries from the /etc/named.conf file.
# Returns    : Array containing all the zone entries.
# Description: Takes a string which is the entire /etc/named.conf file and searches for all zone entries and returns an array with all zone
#              entries.
sub GetZoneEntriesOnly 
{
    @return_array;
         
	foreach ( @_ ) 
    	{
    		$i = index($_, "zone");
		if($DEBUG) { print("\n\"zone\" found at $i"); }
	
    		if( ( $i >= 0  ) ) 
    		{
    			push(@return_array, $_);
    			if($DEBUG) { print("\nDEBUG(GetZoneEntriesOnly): Pushing $_ onto array."); }
    		}
		else
		{
# 			foreach(@array_entries)
# 			{
# 				$current=$_;
# 				foreach(@key_entries)
# 				{
# 					if( index($current,$_) >= 0)
# 					{
 						push(@keep_config_entries,$_);
# 					}
# 				}
# 			}
		}
    	}
    
    return @return_array;
}

# Sub routine: writeEntriesToFile
# Passes     : Nothing
# Returns    : Nothing
# Description: Writes all entries stored in arrays to file.
sub writeEntriesToFile
{
	open(ncf, ">>new_named.conf");
		
	foreach(@keep_config_entries)
	{
		print ncf "$_\n\n";
	}
	foreach(@keep_zone_entries)
	{
		print ncf "$_\n\n";
	}
	close(ncf);
}

# Sub routine: SeparateEntries
# Passes     : Array containing the entire /etc/named.conf file line by line.
# Returns    : Array containing all the entries.
# Description: Takes a string which is the entire /etc/named.conf file and searches for all zone entries and returns an array with all zone
#              entries.
sub ReadConfFile
{
	open(named_conf);

	@contents_named_conf = <named_conf>;

	close(named_conf);

	# Since the contents were read line by line into an array we want to put it into one massive var so it's easier to parse.
	foreach (@contents_named_conf) {
		$content .= $_;
	}
	
	@named_records = split("\n\n", $content);
	
	return @named_records;
}

# Sub outine: Creates a new Associative Array
# Passes    : String, String
# Returns   : Associative Array
# Description: The first argument is a string that will be the key, the second string is the actual record found in the /etc/named.conf.
sub CreateAssociativeArray
{
	my($key,$value) = @_;
	$array{$key} = $value;
	return %array;
}

###################################
# Begin of Main script
###################################

# Back up existing configuration files:
system("mkdir ./named.bak-`date +%F`");
system("cp /etc/named.conf ./named.bak-`date +%F`");
system("cp -R /var/named/ ./named.bak-`date +%F`");


$named_conf = "/etc/named.conf";

@named_records = ReadConfFile();
@r_array = GetZoneEntriesOnly(@named_records);

foreach (@r_array) {
	if($DEBUG) {
		print("\nCurrent Entry: $_");
		print("\nCurrent Domain: " . GetDomainName($_) );
	}
	ProcessDNSRecord( GetDomainName($_), $_ );
}

writeEntriesToFile();

#start cleaning up after ourselves
system("rm -rf temp/*");
system("mv new_named.conf /etc/named.conf");