Multiseat Support in HAL

[David Zeuthen]

On Thu, 2006-09-21 at 22:16 -0700, Artem Kachitchkine wrote:
> Yeah, Sun Ray moves USB traffic over Ethernet. But they don't reuse any 
> of the kernel device driver code - all Sun Ray drivers are in userland 
> and have a different set of APIs. There's a very simple loopback kernel 
> driver that allows them to pretend they're in the kernel - i.e. accept 
> system calls via unix special device files. Where syscall API is not 
> required, e.g. for libusb, we avoid this trip to the kernel.

That's pretty interesting. Just out of curiosity, does this mean that
you don't use in-kernel USB storage / file system drivers for USB
storage on Sun Ray?. Or can you actually channel the USB traffic to
kernel drivers that normally speaks to a USB host kernel driver? (I know
little of Solaris internals, sorry).

Btw, a related idea I had (ok, maybe it's not that related but I'm tired
and rambling so bear with me :-).... for ultra-paranoid mode... one
could use vfat/iso9660/udf/... file systems in user space (via FUSE on
Linux) for untrusted media such as USB sticks and removable media in
general. Should be easy to make HAL's Mount() do this in a way that is
completely invisible to the apps above HAL... However, I'm not sure
these file systems exist for FUSE.

Anyway, these user space file system drivers would then be locked down
via standard mechanisms, SELinux being one example.

    David