Re: RFC: [PATCH] Enable olddelta to be NULL in adjtime(3)

[Samuel Thibault]

Hello,

Svante Signell, on Tue 30 Aug 2016 14:32:32 +0200, wrote:
> The gnumach patch, 80_mach_clock.patch sets the old_adjustment to oadj only if
> old_adjustment is non-null. This patch is probably redundant but included here
> anyway.

It's not only redundant, but actually useless (and thus not fixing
anything).  See the RPC server stub in ./kern/mach_host.server.c:

OutP->RetCode = host_adjust_time((host_t)convert_port_to_host_priv((ipc_port_t) 
In0P->Head.msgh_request_port), In0P->new_adjustment, &OutP->old_adjustment);

i.e. on the server side, mig always provides a room for the RPC to
provide the result, so the pointer is never NULL.

> TODO: EINVAL should also be returned if the supplied delta is too large, as
> described in adjtime(3).

This manual talks about the Linux kernel limitation. There is no reason
to introduce the same limitation.

Samuel