[coyotos-dev] IPC Redesign
Jonathan S. Shapiro
shap at eros-os.com
Tue May 22 15:43:40 EDT 2007
On Tue, 2007-05-22 at 12:24 -0700, Charles Landau wrote:
> >Setting that aside, fully transparent forwarding is not possible in
> >principle, because you need to know what the call/response protocol is,
> Excuse me, but didn't the long discussion on cap-talk about membranes
> and such come to the opposite conclusion? And doesn't the Horton
> protocol involve a transparent forwarder? The only thing you need to
> know about the protocol is where the capabilities are.
No. The long discussion on cap-talk came to the conclusion that E-style
membrane wrapping is not feasible in an OS-style capability system,
because every act of wrapping requires storage allocation
> >All that being said, my view is that the adoption of IDL strongly
> >reduces the importance of this issue. Given an IDL specification, it is
> >possible to automatically generate a forwarder for any given interface.
> Yes, but for a *transparent* forwarder (assuming such a thing is
> possible), I don't see how CapIDL can help. And that is a pity,
> though perhaps not such a large one.
Let me restate: in the presence of IDL, I do not consider a transparent
forwarder to be a high-priority objective.
That said, it is *definitely* important that a forwarder which knows the
alleged IDL be able to detect messages that fail to conform to the
proper payload shape. This is necessary (e.g.) for MLS enforcement.
More information about the coyotos-dev