David R Nessl <[log in to unmask]> writes:
> > An even simpler alternative would be to put the per-user directory
> > somewhere that the users can't access at all.
>
> How?  If end-users own the files (in order to get the charging right),
> then because of the single directory tree in Unix those files will
> always be a accessible by the owners.

You're making things complicated by accounting only by file ownership.
Why not just make a special case for LISTSERV?  Keep list-related files
in directories segregated by user, but owned entirely by LISTSERV.  Then
have your accounting script sum the disk use in the user's LISTSERV
directory with disk use elsewhere on the system.  On my system, to get
my own disk usage I'd total all of

/home/naleks                            ownership naleks:naleks
/home/listserv/notebook/naleks          ownership listserv:listserv
/var/spool/mail/naleks                  ownership naleks:mail

If you have miscellaneous directories that you want to account for
file by file, you could do that too.

> That's a valid concern.  So we should leave those small files
> (LISTNAME.dbXXXX) owned by listserv, but change the ownership on the
> really big files, i.e. the LISTNAME.logXXXX files, for charging.

That sounds really ugly.  And those files aren't small :-)
--
  Norm

Patience is the key to joy.