dbus fork problem

[Peter Clifton]

On Thu, 2007-04-05 at 11:44 +0530, मयंक जैन (makuchaku) wrote:
> On 4/5/07, Sean Kang <sean_kang at samsung.com> wrote:
> > After strugging for a while, we've noticed that dbus connection doesn't seem
> > to work with fork() system call.
> >
> > The connection is copied but there is no API to properly close the
> > connection so the new connection can be made.
> 
> Hi Sean,
> 
> Though I've not used dbus-glib bindings with a system in which I had
> to fork, but maybe you can try dbus_g_connection_unref so that the
> refcount goes to zero & the object is finalized.

Ask the guys on the dbus list about this..

If you have a dbus connection (raw libdbus), and unref it to 0 ref
counts, it DOES NOT finalise. This is a broken API IMHO, but this is the
way dbus behaved for "shared" (default) bus connections, and some
applications rely on the stupid ability to unref, then re-open the same
connection!

I proposed they fix this, but it breaks behavioural (bug) compatibility
with their stable release.

If your app knows no other libraries it has loaded is playing with dbus,
you "might" be able to call dbus's shutdown call, but this doesn't
really work.

In short - once dbus is in your app, you can't get it to leave. The dbus
people I spoke to don't see this as a bug. Certainly, it is a
corner-case of common use dbus gets.

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)