On Tue, 17 Aug 1999, Wilfredo Sanchez wrote:

>   A group of us at Apple are trying to figure out how to handle  
> situations where a filesystem with "foreign" user ID's are present.   
> The basic problem is that the user experience using Unix semantics  
> are not really pleasant.  I think some examples would help:

I was thinking about this the other day, while mousting a series of floppy
disks, and it seems to me that what you're looking for, at least for
removable media, is a sort of single-user UFS that says "Joe Schmoe owns
this file system." Assuming that neither you nor Joe have accounts on each
other's machines:

0) Non-root users should be able to mount disks.  This really goes without
saying for desktop systems.

1) You mount_suufs his disk with some sort of "foreign-user" option, and
the system chooses an unused, per device UID and GID, and all the
directories are mapped to that ownership.

2) You copy the files to a world wrx directory, and they all automagically
become foreign ownership.

3) Joe goes to his computer and mounts his disk, and voila, he owns
everything (it's his filesystem after all).

This handles the simple case of just shuffling files around.  If you
wanted more elaborate collaborations, you'd really have to give each other
accounts.  You could monkey around with keeping passwd files and such on
the medium and umapping, but you couldn't copy files from the Zip to the
local FS without future-user-clash.

This also affords Joe more than your normal level of security, assuming he
trusts root on all the systems involved.

Marc.

--
Marc Ramirez - Owner		Great Big Throbbing Brains
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