U9fs is a program that serves Unix files to Plan 9 machines
using the 9P protocol. It is typically invoked on a Unix
machine by inetd with its standard input and output connected
to a network connection, typically TCP on an Ethernet. It
typically runs as user root and multiplexes access to multiple
Plan 9 clients over the single wire. It assumes Plan 9 uids
match Unix login names, and changes to the corresponding Unix
effective uid when processing requests. U9fs serves both 9P1
(the 9P protocol as used by the second and third editions of
Plan 9) and 9P2000.
