Re: [PATCH v5] net: ip, diag -- Add diag interface for raw sockets

[Jamal Hadi Salim]

On 16-09-28 07:27 AM, Cyrill Gorcunov wrote:
> On Wed, Sep 28, 2016 at 07:06:26AM -0400, Jamal Hadi Salim wrote:
> > > This structure is uapi, so anyone has complete rights to reference
> > > @pad in the userspace programs. Sure it would be more clear to remove
> > > the @pad completely, but if we choose so I think it's better to do
> > > on top instead and then if someone complain we can easily revert
> > > the single trivial commit instead of this big patch.
> >
> > I am conflicted.
> > A field labelled "pad" does not appear to be valid as "UAPI". It is
> > a cosmetic indicator. If you did sizeof() with or without it being
> > present the value doesnt change.
>
> I think you miss the point what I'm trying to say: currently end-user
> may have reference to this member (for any reason) and his program
> will compile and run. If we change the name the compilation procedure
> fails and this will break API. Yes, referrning @pad is bad idea for
> userspace code, and yes (!) better to simply rename it but lets do
> that later, on top, so that if we break something in userspace
> we could easily revert the oneline change.


I understood well your point;-> Maybe my response was not clear:
_nobody should be fscking fondling pad fields_ setting them or
otherwise.
Maybe let these programs fail. I asked if you knew any such app which
did anything with a pad field.

cheers,
jamal