Re: suidpid( UID, credential? ) ? secure IPC? (fwd)

Alan Cox (alan@lxorguk.ukuu.org.uk)
Tue, 7 Oct 1997 08:01:43 +0100 (BST)


> Mainframe's (i.e. IBM MVS, OS/390, et. al.) have a special facility for
> performance cross-address space procedure calls. You can think of them

So does the 80x86 with its call gates.

> MVS programmers have been using this facility for decades to isolate
> highly privileged, or extrememly important code, from other address spaces.
> The facility is there for good reason... Why not go study it, or talk
> to you nearby MVS guru - and try to implement such a facility in Linux.

For users in general its too slow and too expensive to work with. You can
sort of do it in userspace however using modify_ldt and mmap/mprotect in
your own program space if you want.

> Like Durable Queues (essentially SysV message queues that are ACID
> consistent and persist across reboots). I've been finding it a chore to

Ok thats a fun one. A persistent queue - definitely a user space problem
from the unix viewpoint.

> write business-grade applications on Unix without things like cross-address
> space calls, durable queues, etc. Generally, one has to resort to an

"Business Grade" here meaning giant data processing apps ?

Alan