svn commit: r277652 - in head/usr.sbin/pw: . tests

[Slawa Olhovchenkov]

On Sun, Jan 25, 2015 at 04:56:24PM +1100, Bruce Evans wrote:

> Negative ids have historical abuses in places like mountd.  mountd still
> hard-codes -2 and -2 for the default uid and gid of an unprivileged user.
> It at least casts these values to uid_t and gid_t before using them.
> This gives the ids the non-random values of UINT32_MAX-1 if uid_t and
> gid_t are uint32_t.  (If uid_t and gid_t were signed, then it would
> leave the values as negative, so invalid.)  These magic values may work
> better than when ids were 16 bits, since there is less risk of them
> conflicting with a normal id.  However, the non-conflict is probably
> a bug.  FreeBSD uses the magic ids of 65534 for user nobody: group
> nobody.  These would have been (id_t)-2 with 16-bit ids.  They no
> longer match, so ls displays (id_t)-2 numerically.  FreeBSD also has
> a group nogroup = 65553 that doesn't match the nfs usage.  However2,
> in FreeBSD-1 wher ids were 16-bits, nobody was 32767 and nogroup was
> 32766. so they didn't match nfs for other reasons.  The 2 non-groups
> now seem to be just a bug -- FreeBSD-1 didn't have group nobody.
> 4.4BSD-Lite2 has the same values as FreeBSD-1.

This is not full true for ZFS case.
On ZFS nobody is 2^32-2.