Re: 32bit UID support, next patch

[Andreas Jaeger <aj at suse dot de>]

>>>>> Chris Wing writes:

Chris> Andreas:
Chris> Thanks for working on this patch.

>> The patches is essentially Chris' patch with __ASSUME_32BITUIDS added
>> and a bit of reformating.  Chris, the __ASSUME_32BITUIDS allows to
>> configure [1] with e.g. --enable-kernel=2.3.40.  This way all
>> compatibility stuff will be removed and only the new syscalls will be
>> used.

Chris> I'd be careful with this feature-- we don't want people compiling a glibc
Chris> that will crash badly on all kernels older than 2.3.40 unless they know
Chris> what they are doing. If we are going to have such a feature, we might as
Chris> well disable other backwards compatibility while we're at it, like
Chris> non-system call getcwd(), etc.

That's why you have to give it explicitly.  The default is
--enable-kernel=0.0.0.  It doesn't work only for 32bit UIDS - it's
also there for other newly introduced functions.  You can have a look
at sysdeps/unix/sysv/linux/kernel-features.h via
<http://sourceware.cygnus.com/glibc>.  I explained this explicitly to
tell you why these changes are usefull.  For glibc 2.1.x your patch is
just fine.

Chris> Certainly, there should be strong warnings about using this configure
Chris> option in the glibc documentation.
We currently have only (configure --help output):
  --enable-kernel=VERSION compile for compatibility with kernel not older
                           than VERSION

Chris> I haven't had an opportunity to try the patch out yet-- hopefully I can do
Chris> so in a few days.

Please note, it only applies to the CVS version of glibc 2.2.  It will
not apply to glibc 2.1.3 - and I wouldn't advise to use the current
CVS version of glibc 2.2 in a production system.

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.rhein-neckar.de