Demi Marie Obenour <demiobenour@gmail.com> writes:

> I saw that the host-side portal code uses FD 0 for the listening socket.
> Would it be better to use a different file descriptor for that?
> Alternatively, I can dup() /dev/null over stdin.

FD 0 is used on purpose.  This is inetd-style socket activation, a
standard interface supported by service managers.