Re: behavior of NO SENDERS notifications when receive rights move

[Brent W. Baccala]

On Mon, Oct 3, 2016 at 7:00 AM, Kalle Olavi Niemitalo <kon@iki.fi> wrote:

"Brent W. Baccala" <cosine@freesoft.org> writes:

> Now I'm wondering - how would DEAD NAME notifications be handled?  rpctrace
> would want to transfer send rights with the DN notifications attached (so
> it could wrap them both), but my experience, and my understanding of the
> Mach documentation, is that moving a send right with a DN request triggers
> a PORT DELETED notification, which is not what we would want.

Before rpctrace moves the send right from the target task, it
could call mach_port_request_notification to cancel the dead-name
notification request.  This call returns the send-once right to
which the notification would have been sent.  After rpctrace has
moved the rights, it could restore the notification request,
now with a wrapped send right and a wrapped send-once right.

Good idea!  We can also use the same approach to handle no-sender notifications - separate them from the receive rights before moving them both.  So I think we're OK destroying no-sender notifications when moving receive rights.
 

    agape

    brent