GEOM Gate.

[Peter Jeremy]

On Thu, Aug 14, 2003 at 10:29:09PM +0200, Pawel Jakub Dawidek wrote:
>On Thu, Aug 14, 2003 at 09:52:25PM +0400, Buckie wrote:
>+> BTW, QNX had this for a long time, it's called QNet in there. Allows
>+> transparently to mount or use anything in /dev. Even a soundcard!
>
>I think this isn't really hard to implement.

I tend to agree.  I've done some background thinking about this in the
past couple of months and couldn't come up with anything especially
difficult - though deeper thought may reveal something.  The logical
implementation is either as a pseudo-filesystem - aka devfs(5) - or
(more cleanly) a portal.

>But there are two problems:
>1. Device major numbers.

I don't see this as a problem - you do the name to major/minor mapping
on the remote system.  All that goes across the network is the device
name (filename in /dev).  This is the same way that NFS works.  The
device major number is just an easy way for the kernel to map a device
name onto the device-specific functions to access the physical
hardware - this only needs to occur on the server.

>2. Handle network errors.

I think the easiest way is just to pass them back to the application.
This does mean that an application would get unexpected network-related
errors, but there's no obvious alternative.

I can think of a third potential problem:  Handling ioctl()s where the
third argument is a pointer to a structure that itself include pointers
to other data objects.  This would require special casing those ioctls.
(Worse would be SysV-style ioctl's which don't comply with the BSD
request encoding).

Peter