Would a BGW need shmem_access or database_connection to enumeratedatabases?

I'm thinking of writing a background worker that will enumerate
the databases present, and spin off, for each one, another BGW
that will establish a connection and do stuff.

For the "master" one, what capabilities will it need to simply
enumerate the current names of known databases? I suppose I could
have it connect to the null dbname and query pg_database. Would
that be the civilized way to do it, or am I missing a simpler way?

-Chap