touching devices through RFS

[Doug Gwyn]

In article <1617 at ulysses.homer.nj.att.com> ekrell at ulysses.UUCP (Eduardo Krell) writes:
>> If so, how does it know which of the values
>>in the structure parameter need to be rearranged because of
>>byte-ordering and structure alignment differences?
>
>RFS uses internally a canonical form to pass arguments back and forth between
>the server and the client machines. The caller converts its arguments into this
>canonical form and the callee converts this canonical form back into structures
>or whatever types are needed, making it independent of any byte-ordering or
>alignment requirements.

First, thanks for providing helpful information.  It's appreciated.

Second, there would seem to still be a problem with ioctls, since the
third argument to an ioctl is either an int or a struct pointer; the
int is no problem but how in the world is the struct pointer dealt
with?
	a) Is a remote copy-in/copy-out done?  (e.g. for a struct
		termio in a TC[GS]ET* ioctl)
	b) What about the case when the kernel doesn't know about
		the internals of the particular structure used by
		the specific ioctl command code?  (e.g., when
		accessing a remote device special file such as a
		frame buffer interface, when the local system was
		unaware of the possibility of the remote
		heterogeneous system supporting such a device)
It seems to me that such data structures would have to be self-
describing in the general case.  Of course any that are universal
(such as struct termio) could be mapped correctly on each end since
each system knows their structure.

P.S.  This ioctl-over-network issue keeps coming up and getting in
the way of standardizing ioctls in IEEE 1003 (POSIX).