Re: task-server hacking

[Niels Möller]

Marcus Brinkmann <address@hidden> writes:

> The rootserver is the only server privileged in L4.  So the rootserver will
> do the following:
[...]
> The privileged calls will be done to the rootserver.  This all still has to
> be written.

This sounds like a useless indirection to me.

We'd have

  root server: Wrapper interface for the privileged system calls
  (including the ones needed by the task server), and restricted to
  take requests only from the task server.

  task server: Accepts user tasks' requests, adds book-keeping,
  accounting id:s and death notifications.

  proc server: Keeps posix state about tasks, and access control for
  interprocess interaction.

Perhaps the task server (if it's small and lean enough) can be a
module (and a few threads) loaded into the root server address space.
That is, merge the first two layers. And you suggest merging the
latter two ;-)

Anyway, I think I'd prefer to have the code written as if it can use
the privileged system calls directly, and if needed have stubs that
direct those calls to the right root server thread instead.

> I think we want to use IDL for that server already, and possibly handles.
> As to the detail of sednign messages and such, I am still playing with that
> myself.  The first pager I wrote didn't work for some reason :)

I haven't looked into the IDL alternatives at all yet. For hurd
servers, I think we want an IDL that understands handles and the
handle transfer protocols. Writing a few servers by hand should be a
good way to figure out what code the IDL processor process and
generate.

Regards,
/Niels