Share dbus session outside the session.

[Weng Xuetian]

Hi DBus world,
I have dbus program that may initially start in an x server, but I may
let user to use/call/control it from tty with another program.
How should I get the same dbus connection out side the session?

I have an idea that I can specify the same dbus address, write the
address into a file so other client and read the address from file.
But seems there is no way to get the address from a connection, but
DBUS_SESSION_ADDRESS is not always set, from the dbus implementation I
found the DBUS_SESSION_BUS_DEFAULT_ADDRESS, but I don't think it's a
good way though.

So I wonder what's the correct approach for this case?

Regards.