[ACL-Devel] archiving acls: tar and cpio

[Michael Tokarev]

Mats Wichmann wrote:
> 
[]
> >>   How about this two (separator does not matter):
> >>   user:oracle:23:rwx,group:dba:50:r-x,...
> >>   user:oracle#23:rwx,group:dba#50:r-x,...
> >>   user:#23:rwx,...  -- this one if there is no username for uid 23
> 
> why is anything necessary at all?  historically restores have
> worked whether there's a user database entry or not... after all,
> the "username" is only a convenience in displays from, say, "ls -l".

There are two goals here.  One is for `restore' case where you want
to restore files from e.g. backup -- numeric ids as a best here.
And another is to be able to transfer archive to another machine
and extract it there -- with this, "named" method preferred.

I don't know the best way of handling both goals.  One way is to have
an option for pax/tar/etc to use either numeric or symbolic ids
(e.g. -n use [ug]id, without -n use [user,group]name).  Another way is
to use different utilities for different tasks (e.g. dump/restore
can only operate with [ug]ids, not with names).  Cpio (standard one)
has no user/group names stored.  Old tar also has only [ug]id, but
never tars have ability to store names also, and some (notably gnu)
implementations default to use names on restore (gtar implements
third, "adaptive" way -- attempt to extract using username, and if
that fails (no such name), warn and use uid instead -- this should
be the best way, but it also has it's own disadvantages).

[]
> >User names starting with a digit are rejected on my current (Linux)
> >system. Any commas ad colons are rejected, too.
> 
> commas and colons are illegal.  I can't find anything that
> the use of digits in usernames, however.

It's ok to edit /etc/passwd and insert a comma where appropriate... :)
Colon is not allowed in /etc/passwd or similar; but it is ok in
e.g. ldap, nis, nisplus etc...   No, I'm not about having ability
to store usernames with colons and commas :)

Regards,
 Michael.
To Unsubscribe: send mail to majordomo at cyrus.watson.org
with "unsubscribe posix1e" in the body of the message