Re: Some doubious code in pgstat.c

On Thu, Nov 5, 2020 at 11:18 AM Kyotaro Horiguchi
<horikyota.ntt@gmail.com> wrote:
>
> At Wed, 4 Nov 2020 22:49:57 +0900, Masahiko Sawada <sawada.mshk@gmail.com> wrote in
> > On Wed, Nov 4, 2020 at 6:49 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > >
> > > On Wed, Nov 4, 2020 at 2:25 PM Kyotaro Horiguchi
> > > <horikyota.ntt@gmail.com> wrote:
> > > >
> > > > Hello.
> > > >
> > > > While updating a patch, I noticed that the replication slot stats
> > > > patch (9868167500) put some somewhat doubious codes.
> > > >
> > > > In pgstat_recv_replslot, an assertion like the following exists:
> > > >
> > > > >       idx = pgstat_replslot_index(msg->m_slotname, !msg->m_drop);
> > > > ..
> > > > >       Assert(idx >= 0 && idx < max_replication_slots);
> > > >
> > > > But the idx should be 0..(max_replication_slots - 1).
> > > >
> > >
> > > Right.
> > >
> > > >
> > > > In the same function the following code assumes that the given "char
> > > > *name" has the length of NAMEDATALEN.  It actually is, but that
> > > > assumption seems a bit bogus. I think it should use strlcpy instead.
> > > >
> > >
> > > Agreed.
> >
> > +1
> >
> > The commit uses memcpy in the same way in other places too, for
> > instance in pgstat_report_replslot_drop(). Should we fix all of them?
>
> Absolutely. the same is seen at several places.  Please find the
> attached.
>
> As another issue, just replace memcpy with strlcpy makes compiler
> complain of type mismatch, as the first paramter to memcpy had an
> needless "&" operator. I removed it in this patch.
>
> (&msg.m_slotname is a "char (*)[NAMEDATALEN]", not a "char *".)
>

The patch looks good to me.

Regards,

-- 
Masahiko Sawada
EnterpriseDB:  https://www.enterprisedb.com/