Giving Apache sudo access

[Jared]

I have a line in sudoers which gives Apache sudo access
to run *a single script* in a specific location, outside
the htdocs tree:

apache ALL=(ALL) NOPASSWD: /usr/bin/php -f /path/sudo_app.php

Thus the apache user can run this single command.

Because I can't seem to pass command-line arguments ($argv) to
this sudo_app, I write a tiny tmp file. In htdocs, I have
a small php script: 'app.php':

<?php
file_put_contents('/tmp/vars.txt',"$_GET[a]\n$_GET[b]");
`sudo /usr/bin/php -f /path/sudo_app.php`
?>

($_GET[a] represents an argument passed through the URL
like this: http://localhost/app.php?a=1&b=2)

Inside sudo_app.php, I open /tmp/vars.txt, read the two
variables, and pass them with full root access to the rest
of the script, which accesses /dev/ttyS0. Then the script
deletes the /tmp files.

It works, but it seems more complicated than it should be,
involving two scripts, a tmp file, and a line in /etc/sudoers,
in order to run a single command.

Does anyone have another idea for giving an apache module
the ability to have root access to /dev/ttyS0, without
compromising the box?

-Jared