Subject: Re: increasing NGROUPS_MAX
To: Jan Schaumann <jschauma@netmeister.org>
From: Brian Ginsbach <ginsbach@NetBSD.org>
List: tech-userlevel
Date: 08/02/2005 21:43:50
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On Tue, Aug 02, 2005 at 01:33:07PM -0400, Jan Schaumann wrote:
> Hi,
>
> In order to increase the number of supplemental groups a user can be in,
> one needs to bump NGROUPS_MAX in the sources.  This will require a
> rebuild of the kernel but also of the userland tools that use
> NGROUPS_MAX.
>
> This could be made less intrusive if the userland tools would use
> sysconf(_SC_NGROUPS_MAX) instead.  Of course this means that all those
> tools that currently use static arrays initialized to NGROUPS_MAX + 1
> need to be redone dynamically...
>

Be aware that just changing NGROUPS_MAX could cause all sorts of
problems since this value is also used for NGROUPS.  And NGROUPS
is used by things like RPC credentials (i.e. NFS) which doesn't
provide for any more than 16 simultaneous groups...

Any userland tools and library routines that initialize static arrays
to NGROUPS will also need to be redone dynamically.

Brian

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