foreach my $x ($q->param()) {
  # if a file upload: my $filename = $q->param($x);
  # loop read in the file: my $filedata = $buffer;
  $q->param('_filename', $filename);
  $q->param('_filedata', $filedata);
}

# a bunch of other stuff.
# this is to :sigh: mail the file to someone remote

$q->param('_filedata',encode_base64($q->param('_filedata')));
# stuff the data into an attachment by hand