use CGI qw(:standard);

if ($ENV{'REQUEST_METHOD'} eq "POST") {
  my $data = param('snoop');
  unless ($data) {
    # Tasty honey
    open(DENY, ">>.htaccess") or die "Tried to add host (" . $ENV{REMOTE_ADDR} . ") to deny list, but failed to open file\nError: " . $!;
    flock(DENY, 2); # <-- Lock the file
    print DENY "Deny from " . $ENV{REMOTE_ADDR} . "\n";
    close(DENY) or die "Tried to close deny list but failed (Host: " . $ENV{REMOTE_ADDR} . ")\nError: " . $!;
    die;
    }
  }