<group> is a numeric user/group ID instead of a user/group name (as
explicitly intended to be allowed by both the manual page and the
implementation).
Before this fix, mdmfs(8) aborted:
| # mdmfs -s 32m -w 0:0 md /var/tmp/foo
| Assertion failed: (mip->mi_have_uid), function extract_ugid, file /usr/src/sbin/mdmfs/mdmfs.c, line 555.
| Abort trap (core dumped)
The "mi_have_[ug]id" fields were only set in case a name lookup was
successful. Instead they also have to be set in case the string to
integer conversion was successful.
Additionally, as a result of this fix, two assertions at the end of
the function are now always true and hence can be just be removed. It
is guarrantied that both the UID and the GID are set when the function
returns regularily, else it would have been already bailed out with
usage()/exit(3) or errx(3) before.
Spotted by: Christoph Schug <chris@schug.net>
MFC after: 3 days
de90a634cb