#!/usr/bin/perl
# a40404.pl 2007-9-27 by akebia
# Rapid logresolve
# http://nyan.co.uk/akebia/item/73

use threads; use Thread::Queue;

$log_buffer_size = 65536;
$dns_children    = 128;
$dns_cache_file  = 'dns_cache.txt';
$dns_cache_ttl   = 259200;
$dns_show_state  = 0;

@log_buffer  = ();                %dns_cache  = ();
$dns_request = new Thread::Queue; $dns_result = new Thread::Queue;

sub dns_thread
{
  for(;;){
    my $i = $dns_request->dequeue;
    if($i eq ''){$dns_request->enqueue(''); last;}
    my $a = gethostbyaddr(pack("C4", split(/\./, $i)), 2);
    if($a !~ /[^\.\s]+/){$a = $i;} $dns_result->enqueue("$i,$a");
    if($dns_show_state){
      print STDERR $dns_request->pending.' '.threads->self->tid()." $i $a \n";
  } }
}

sub save_dns_cache_file
{
  my $f, $w; unless(%dns_cache){return;}
  if(open($f, '>'.$dns_cache_file)){
    foreach $w (keys(%dns_cache)){
      if($dns_cache{$w}[0] eq '-'){next;}
      print $f "$w,$dns_cache{$w}[0],$dns_cache{$w}[1]\n";
  } close($f);}
}

sub empty_log_buffer
{
  my $i, $a, $t = time; for(;;){
    $i = $dns_result->dequeue; ($i, $a) = split(/,/, $i);
    $dns_cache{$i}[0] = $a; $dns_cache{$i}[1] = $t;
    if($i eq $log_buffer[0][1]){last;}
  }                     for(;;){
    print $a.$log_buffer[0][2]; shift(@log_buffer); unless(@log_buffer){last;}
    if($log_buffer[0][0]){$a = $log_buffer[0][1]; next;}
    $a = $dns_cache{$log_buffer[0][1]}[0]; if($a eq '' || $a eq '-'){last;}
  }
}

my $i, $f = ''; my %a = ();

foreach(@ARGV){
 if(substr($_, 0, 1) eq '-'){$f = $_; $a{$f} = []; next;}
 if($f ne ''){push(@{$a{$f}}, $_);}
}
if($a{'-b'}){$log_buffer_size = $a{'-b'}[0];}
if($a{'-n'}){$dns_children = $a{'-n'}[0];}
if($a{'-d'}){$dns_cache_file = $a{'-d'}[0];}
if($a{'-t'}){$dns_cache_ttl = $a{'-t'}[0];}
if($a{'-e'}){$dns_show_state = 1;}

if($dns_children < 1){exit(-1);}
for($i = 0; $i < $dns_children; $i++){threads->new(\&dns_thread);}

if(open($f, $dns_cache_file)){
  $i = time; while(<$f>){
  if(/(.+),(.+),(.+)[,\n]/){
  if($i - $3 > $dns_cache_ttl){next;}
  $dns_cache{$1}[0] = $2; $dns_cache{$1}[1] = $3;
}} close($f);} 

$SIG{'INT'} = sub{save_dns_cache_file; exit(-1);};

while(<STDIN>){
  my $a, $t = index($_, ' '); $i = substr($_, 0, $t); $f = substr($_, $t);
  if($i =~ /^\d+\.\d+\.\d+\.\d+$/){$a = $dns_cache{$i}[0];}else{$a = $i}
      if($a eq '-'){
    $t = []; push(@log_buffer, $t); $$t[0] = 0; $$t[1] = $i; $$t[2] = $f;
  }elsif($a ne '' || $i eq ''){
    unless(@log_buffer){print $a.$f; next;}
    $t = []; push(@log_buffer, $t); $$t[0] = 1; $$t[1] = $a; $$t[2] = $f;
  }else{
    $dns_request->enqueue($i); $dns_cache{$i}[0] = '-';
    $t = []; push(@log_buffer, $t); $$t[0] = 0; $$t[1] = $i; $$t[2] = $f;
  }
  if(@log_buffer < $log_buffer_size){next;}
  empty_log_buffer;
}
while(@log_buffer){empty_log_buffer;} save_dns_cache_file;
$dns_request->enqueue(''); foreach(threads->list()){$_->join;}