Re: offtopic: userland active context switches ?

Marnix Coppens (maco@telindus.be)
Fri, 06 Aug 1999 17:33:24 +0200

At 15:54 6/08/99 +0100, you wrote:
>During a system call the userspace process switches to kernel mode and
>the kernel executes the code on behalf of the process.
>Is it possible to create a client/server pair both in userspace where the
client
>can pull off the same context switch trick and run code in the server
along the
>same lines ?
>

Solaris Doors are similar to this. Richard Stevens' IPC book
http://www.kohala.com/~rstevens/unpv22e/unpv22e.html has a link to
a Linux implementation: http://www.rampant.org/doors .

Doors are like LPC (local procedure calls), except that a new thread
is created in the server (when initializing the doors mechanism), in
which the client can run server code, with the full Unix permission
mechanism and all.

Marnix Coppens

---
Reality is that which                   | Artificial Intelligence
when you stop believing                 | stands no chance against
in it doesn't go away. (Philip K. Dick) | Natural Stupidity.




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