[interfacekit] Re: BSession

Adi Oanca <adioanca@xxxxxxxxx> wrote:
> > How can this make any sense?
> > There are several possibilities for a port write (or read) to fail, 
> > it 
> > doesn't have to be that the port no longer exists. For example, 
> > BeOS 
> > has a limit of how much memory can be in all ports in the system, 
> > this 
> > is not related to the application.
>       And if this happens, the app should not fail?

Not at all. Not something as important as the app_server.

> > An even more important thing to consider is B_INTERRUPTED - that 
> > can 
> > happen in all user space code and it should probably be resistant 
> > against it. 
>       I know about it for a long time, but I haven't modified BSession. 
> Lazy 
> me! :-)

You should put "ToDo" items in the code, then. That would not only be a 
reminder for you, but also a hint for someone who is reviewing the 
code.

> >>    No, all datas will be dumped until the next code is recognized.
> >>    I know about this... and I had in plan to suffix each 
> > > instruction 
> >>with... AS_END_INSTRUCTION.
> > How could this help? What you could do is something similar to what 
> > TCP 
> > is doing: have a packet counter.
>       And manually calculate the byte count of a massage? Don't you think 
> that is a bit... odd and unpractical? Remember that the tail of an 
> instruction may be in another BSession message.

Why manually calculate the byte count? If a packet number doesn't 
match, the app_server could reset the connection and ask for the whole 
thing again.
But anyway, out-of-sync kind of errors would only be possible if the 
sender doesn't work correctly, i.e. if it would not do any error 
checking.

> >>    In 99.99999% of cases this won't happen. Unless a bad user or 
> >>program 
> >>will write to a ServerWindow port. I have discussed this with 
> > > Michael 
> >>and he said it is not concerned by security.
> > If we can do 100% we should do it. This is not "just" a user 
> > application that would die, this is a system component; the 
> > standards 
> > should be a big higher here.
>       app_server would not die! just one of its threads!

If it would just sit on a port, there probably wouldn't be a problem, 
but who guarantees that it won't crash (in which case the whole 
app_server would be taken down)?

Bye,
   Axel.

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