[haiku-appserver] Re: communication

  • From: "Axel Dörfler" <axeld@xxxxxxxxxxxxxxxx>
  • To: haiku-appserver@xxxxxxxxxxxxx
  • Date: Tue, 07 Jun 2005 19:01:43 +0200 CEST

Adi Oanca <adioanca@xxxxxxxxxxxxx> wrote:
> Axel D=F6rfler wrote:
> > [checksum]
> >>    If I send a pachet with a good checksum and malformed data
> >>they we're sure for a server crash.
> > Those messages would be accepted by the app=3D5Fserver, yes, but 
> > that's not 
> > a problem, as only malicious code would do that :-)
>       Aren't you targeting malicious code with the checksum field=3F

Not really, rather wrong or bad code :-)
It's probably not really needed later on (with real security services), 
and easily circumvented by current code, so maybe I should just drop it 
for now.

> > Also, the app=3D5Fserver should *never* crash, no matter what kind of 
> > junk 
> > is in such a message. It's really not hard to achieve this, and 
> > it's a 
> > necessity as well.
>       I agree. But checking every parameter for validity would impose a 
> huge 
> performance penalty.

Not at all. Sending the stuff over the port is where the penalty is. A 
"if (a < 0)" is certainly completely negligible in this context.

> >>    But they do. Mouse messages arrive in a RootLayer's port which 
> > > is
> >> responsible for moving windows also.
> > I know that they do now, it's just wrong to do so. Moving a window 
> > (ie. 
> > update it on screen) can take a long time, and there is no way to 
> > stop 
> > all other message processing during that time.
>       RootLayer will have a big message queue. I was thinking around 500 
> or 
> more, so I think we won't be having a port full problem especially 
> because this will be a high priority thread.

It's not about a full port problem. It's about responsiveness. The 
current design is just not taking that into account at all.


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