D-Bus service activation and access control

[Lawrence D'Oliveiro]

On Fri, 28 Jul 2017 13:16:21 +0200, David Sommerseth wrote:

> What I wonder is if the session manager, being started via D-Bus
> activation, can it connect to a user's session bus?  And could this
> work across users?  This could enable running two different instances
> of the configuration manager; session bus for user only configuration
> and system bus for system wide configurations.  When connecting to the
> session manager for a user specific configuration it will require a
> logged in user - so the session bus is expected to be available.

Something started on the session bus has access to the system bus, not
the other way round.

The obvious thing to do might be to have per-session-bus peers for
session manager and configuration manager, which will in turn
communicate with the systemwide processes (via some private channel,
which might not even use D-Bus).