Any specific reason you got to do it before mage::run is called in index.php?
Are you concerned they get changed?
Attempting to log at that point would require you to adjust core file (index.php) which is not good practice.
In Mage::run you get:
'scope_code' => $code,
'scope_type' => $type,
'options' => $options,
The variables you are interested in is unchanged at this point.
in Mage_Core_Model_App::run you get this line of code:
thus magento internals nicely saves the params used for you in the registry.
To log them, you can use the event 'controller_front_init_before' which is one of the earliest (usable) events fired.
In that event you can pull the saved params, and log them.
$params = mage::registry('application_params');
To note is that this would place a drastic overhead on your sites performance, as it will log on every request. Curious why you would need to do log them?
Earliest usable event