Re: task-server hacking

[Marcus Brinkmann]

On Thu, May 22, 2003 at 11:28:25AM +0200, Niels Möller wrote:
> The first thread calling task_master() is considered privileged.

It's a bit too early to set such things into stone.  I was thinking about
having task and proc into the same program, so they can share data
structures for performance (and to avoid the need to design a performant and
convenient interface between task and proc right from the start).  However, 
that is an implementation detail.  My initial thought was a task control
object that you then have handles for, but maybe that is too heavy.

> should usually be a thread in proc. I'm not sure how bootstrapping
> should work, but the thread calling thread_master should probably have
> a task id allocated, and it's version field changed to reflect that
> (otherwise, it can't be treated as a task).

The rootserver is the only server privileged in L4.  So the rootserver will
do the following:

* It will set up an environment for itself.
* It will create and setup the initial tasks according to the grub boot
  info.  This can be programs bootstrapping subsystems, or whatever.  It's
  not clear to me what.  The rootserver will also have some boot script
  parsing stuff like we are currently using.
* Then it will turn itself into a server that can be used by subsystems to
  perform privileged system calls more or less directly.

Neal already wrote some code to do all thatm but I wouldn't consider
everything to be fleshed out into the last detail.

> As this is the first L4 code I've ever written, I really appreciate
> comments on the code.

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 tested this at all, of course... How should the server be
> started? It's no root server, but it is intended to run as a
> privileged server, and naturally needs to use privileged L4 system
> calls.

Currently we have no documented case of successfully starting a program from
within the rootserver :)

The privileged calls will be done to the rootserver.  This all still has to
be written.

Thanks,
Marcus



-- 
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Marcus Brinkmann              The Hurd http://www.gnu.org/software/hurd/
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