Re: [libvirt] [PATCH]: don't harcode buffer for getgrnam_r

[Guido Günther <agx sigxcpu org>]

On Thu, Apr 16, 2009 at 02:40:44PM +0100, Daniel P. Berrange wrote:
> On Thu, Apr 16, 2009 at 02:14:13PM +0200, Guido G?nther wrote:
> > On Thu, Apr 16, 2009 at 09:56:27AM +0200, Daniel Veillard wrote:
> > > On Thu, Apr 16, 2009 at 09:19:38AM +0200, Guido Günther wrote:
> > > > Hi,
> > > > determines the maximum needed buffersize for getgrnam_r using sysconf
> > > > instead of hardcoding it to 1024 and increases the buffer on ERANGE.
> > > > The latter is needed since sysconf is allowed to return -1. Furthermore
> > > > some glibc versions seem to return a too small buffer on amd64
> > > > (http://bugs.debian.org/520744). O.k. to apply?
> > > 
> > >   It looks a bit weird, using sysconf but 1/ allowing it to fail so
> > > doing the 2/ 1024 value and loop on ERANGE , but well if I understand
> > > correctly taht's forced by some glibc broken behaviour.
> > Yes, sysconf is allowed to return -1 here.
> > 
> > >   My take is that the *= 2 size loop should be bounded to avoid eating
> > > all memory on some intermediate not size related error. Can we really
> > glibc shouldn't return ERANGE then, but better safe than sorry. I've
> > added that check in the attched patch.
> 
> ACK.
Applied now.
 -- Guido