[9fans] Plan9 permissions

[Lucio de Re lucio@proxima.alt.za]

> 
> i don't know.  that implies that the log process is not
> running as you, i.e. is running as none or another user, like "upas".
> if another user, then make that user the owner of the file.
> if "none", think strongly about the append-only flag.
> the editors warn about that, and it encourages others not
> to edit the file either.
> 
Russ,

you're missing a point here.  On the one hand, quite correctly, the 
owner has one "permission" bit no-one else can alter, namely ownership.

On the other, making group and other inclusive does not gain you 
anything, it is better to make them exclusive, as Unix does, so that 
you can stop the owner from accessing something while allowing 
arbitrary users, than to have no means whatsoever to achieve this 
objective.

There's nothing compulsory about it, nobody has to use the permissions 
in this fashion, but removing the facility by opting for the 
intuitively obvious approach, decreases the flexibility of the tool.

>From the BSD man pages:

     [EACCES]      Permission bits of the file mode do not permit the request-
                   ed access, or search permission is denied on a component of
                   the path prefix.  The owner of a file has permission
                   checked with respect to the ``owner'' read, write, and exe-
                   cute mode bits, members of the file's group other than the
                   owner have permission checked with respect to the ``group''
                   mode bits, and all others have permissions checked with re-
                   spect to the ``other'' mode bits.

Note the "members of the file's group _other_than_the_owner_" and the 
implicit similar exception in the "other".  This reads precisely as 
David would have it.
-- 
Lucio de Re (lucio@proxima.alt.za)
Disclaimer: I'm working at getting my opinions to agree with me.