[RFE] Support signaling only connections owned by specific uid

[David Rheinsberg]

Hi

On Thu, 8 Apr 2021 at 11:12, Bogdan Lotko <bogdan at lotko.at> wrote:
> I don't know the details, but is it not much more simple to make a
> broadcast and process the message only in applications that belong to
> specified user?

To extend on that, a simple solution is to only broadcast public
information and require callers to request more data via a
method-call. This method-call can then be guarded by uid verification,
etc. The D-Bus `PropertiesChanged` signal allows for a simple solution
by utilizing the `invalidated-properties` feature, rather than
including payload directly in the signal.

On a different note, you can always send directed-signals as unicasts
to all interested/authorized parties. These will not be proper
multicasts, though, thus subject to re-ordering.

David