clamdownloader.pl

#!/usr/bin/env perl
#
# File name: clamdownloader.pl
# Author:    Frederic Vanden Poel
#
#############################################################################
#

use strict;
use warnings;

use Net::DNS;

my $clamdb="/tmp/clam";
# mirror where files such as daily-12133.cdiff exist
my $mirror="http://database.clamav.net";

# get the TXT record for current.cvd.clamav.net
my $txt = getTXT("current.cvd.clamav.net");

exit unless $txt;

chdir($clamdb) || die ("Can't chdir to $clamdb : $!\n");

# dump the record in a file
print "TXT from DNS: $txt\n";
open D, ">dns.txt";
print D "$txt";
close D;

# temp dir for wget updates
mkdir("$clamdb/temp");

# get what we need
my ( $clamv, $mainv , $dailyv, $x, $y, $z, $safebrowsingv, $bytecodev ) = split /:/, $txt ;

print "FIELDS main=$mainv daily=$dailyv bytecode=$bytecodev\n";

updateFile('main',$mainv);
updateFile('daily',$dailyv);
updateFile('bytecode',$bytecodev);


sub getTXT {
  use Net::DNS;
  my $domain = shift @_;
  my $rr;
  my $res = Net::DNS::Resolver->new;
  my $txt_query = $res->query($domain,"TXT");
  if ($txt_query) {
    return ($txt_query->answer)[0]->txtdata;
  } else {
    warn "Unable to get TXT Record : ", $res->errorstring, "\n";
    return 0;
  }
}

sub getLocalVersion {
  my $file=shift @_;
  my $version = -1;
  my $cmd="sigtool -i $clamdb/$file.cvd";
  open P, "$cmd |" || die("Can't run $cmd : $!");
  while (<P>) {
    next unless /Version: (\d+)/;
    $version = $1;
    last;
  }
  close P;
  return $version;
}

sub updateFile {
  my $file=shift @_;
  my $currentversion=shift @_;
  my $old=0;
  if  ( ! -e "$file.cvd" ) {
    warn "file $file.cvd does not exists, skipping\n";
  }
  if  ( ! -z "$file.cvd" ) {
          $old = getLocalVersion($file);
    if ( $old > 0 ) {
            print "$file old: $old current: $currentversion\n";
            # mirror all the diffs
            for (my $count = $old + 1 ; $count <= $currentversion; $count++) {
                    print `wget -nH -nd -N -nv $mirror/$file-$count.cdiff 2>&1`;
            } 
    } else {
      warn "file $file.cvd version unknown, skipping cdiffs\n";
    }
  } else {
    warn "file $file.cvd is zero, skipping cdiffs\n";
  }
  
  return if ( $currentversion == $old );

  # update the full file using a copy, then move back
  print `cp -v -a $file.cvd temp/$file.cvd 2>&1`;
  print `cd temp && wget -nH -nd -N -nv $mirror/$file.cvd 2>&1`;
  if  ( -e "temp/$file.cvd" && ! -z "temp/$file.cvd" ) {
    if ( (stat("temp/$file.cvd"))[9] > (stat("$file.cvd"))[9] ) {
      print "file temp/$file.cvd is newer than $file.cvd\n";
      print `mv -v temp/$file.cvd $file.cvd 2>&1`;
    } else {
      print "file temp/$file.cvd not touched by wget\n";
      print `rm -v temp/$file.cvd`;
    }
  } else {
    warn "temp/$file.cvd is not valid, not copying back !\n";
    unlink "temp/$file.cvd";
  }
}

__END__