STEPHEN WHITE'S PROPOS
Ian Jackson writes:
> Stephen White's scheme has a serious disadvantage compared to most
> other arrangments: it becomes very hard for users to control access
> to their files effectively.
>
> This is because they can't chgrp any files with different ownerships
> back to the state they were in when they were created in their home
> directory (because they're not a member of the group). The only way
> to do it is to make a new copy of the file and delete the old one.
> This would be quite tedious in the case of directory trees and even
> more so in the case of files with multiple hard links.
When users start manually manipulating permissions (like above), then the
automagical aspects of private groups do tend to become less useful. I don't
agree that the above problem is a serious disadvantage.
The above only applies to the situation where a user has made files in their
own directory available with the chgrp command, and then wishes to hide them
again. In this circumstance, the user can do "chmod g-rwx file" to achieve the
same effect that a "chgrp private file" would achieve (were it possible).
> It should also be noted that Stephen White's proposal won't work
> unless the home directories filesystem and /tmp are both mounted
> with BSD semantics.
Only the home directories filesystem needs to be mounted with BSD semantics.
However, your main point is still correct, and I hadn't spotted this.
My proposal was worked out with the assumption that things were mounted with
BSD semantics. I did this because Remy (author of the ext2 file system) is
seeing if he is allowed to make the Linux kernel default to BSD mounting.
If Linus chooses to retain SysV defaults, then that marks the end of this
thread. If BSD mounting becomes the default, then the setgid debate needs to be
reviewed from the other direction ("Should we retain non-standard SysV
semantics with a 'nogrpid' in /etc/fstab?").
So unless BSD mounting becomes the default, I suggest that my proposal be
shelved. I would still welcome comments from the people who opposed multiple
private groups. I would like to know if my proposal suited their needs better.
Steve.
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