r2868: Well, I'm not quite sure what I'm doing back in Samba 3.0, but anyway...

r2868: Well, I'm not quite sure what I'm doing back in Samba 3.0, but anyway...

I've been grumbling about under-efficient calls in SAMR, and finally
got around to fixing some of them.

We now call sys_getgroups() (which in turn calls initgroups(), until
glibc 3.4 is released) to figure out a user's group membership.  This
is far, far more efficient than scanning all the groups looking for a
match, and is still the 'posix way', just using an effiecient call.

The seperate issue of 'who is in this group' remains, but this one has
been biting some people.

I need to talk to VL about how best to exersise nasty corner cases,
but my initial tests hold strong.  (The code is also much simpiler
than before, which has to count for something :-)

Andrew Bartlett
(This used to be commit dc19f161698dab5b71d61fa2bacc7e7b8da5fbba)