Re: NGROUPS_MAX

From: Frank van Maarseveen (F.vanMaarseveen@inter.NL.net)
Date: Thu Oct 05 2000 - 17:16:52 EST


On Wed, Oct 04, 2000 at 09:39:11AM +1300, Craig Whitmore wrote:
> I need to set up a server with a user that is in more than 32 groups at a time
> and as far as I know NGROUPS_MAX in limits.h changes this maximum.
> If I increase (say to 256) this will this break anything or will linux work perfectly
> well?
It's almost time for a FAQ.

For RH 6.1 which uses glibc-2.1.2 you need to take the following steps:

1) modify the kernel headers glibc uses (separately installed on RH6.1)

        linux/include/linux/limits.h: change NGROUPS_MAX
        linux/include/asm-i386/param.h: change NGROUPS accordingly

2) recompile glibc
3) install/upgrade it.

When you have users in >16 groups working on an NFS client this will
break: the RPC protocol passes only the first 16 groups to the server. I've various
NFS client side patches to eliminate this problem (2.2.x, 2.4.0-test*, see
also http://www.inter.nl.net/users/fvm/nfs-ngroups)

I've set NGROUPS_MAX to 256, no problems.

-- 
Frank
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sat Oct 07 2000 - 21:00:18 EST