I have a network of blogs that link to each other. The problem is when I want to get the primary blog's domain. I need it for things like the the target of the logo when clicked.

I can't seem to find a function in WPMU the retrieves this. I can see the value I want in the wp_site table. I could easily get it with $wpdb, but its a bit over kill, and if there is a function that can get the value already, then I want to use it.