In Unix the only way to get root privileges is by executing a setuid root program. You could make your script setuid and use suidperl, or you could run a separate setuid program such as "su".

If your script is setuid, then you don't have to request a root password since you can regain root privileges after dropping them just by re-exec'ing your script. It's generally a good idea to drop root privileges any time you don't need them by $)=$(; $>=$<;.

If you're using "su" you'll need to use Expect or Expect::Simple to feed the password to the "su" command.