Re: [nft PATCH v2] src: use reentrant getprotobyname_r()/getprotobynumber_r()/getservbyport_r()

[Thomas Haller <thaller@redhat.com>]

Hi Pablo,

On Fri, 2023-08-18 at 11:57 +0200, Pablo Neira Ayuso wrote:
> 
> > -       struct protoent *p;
> > -
> >         if (!nft_output_numeric_proto(octx)) {
> > -               p = getprotobynumber(mpz_get_uint8(expr->value));
> > -               if (p != NULL) {
> > -                       nft_print(octx, "%s", p->p_name);
> > +               char name[1024];
> 
> Is there any definition that could be used instead of 1024. Same
> comment for all other hardcoded buffers. Or maybe add a definition
> for
> this?

Added defines instead. See v3.

[...]

> >  #include <nftables.h>
> >  #include <utils.h>
> > @@ -105,3 +106,90 @@ int round_pow_2(unsigned int n)
> >  {
> >         return 1UL << fls(n - 1);
> >  }
> > +
> 
> Could you move this new code to a new file instead of utils.c? We are
> slowing moving towards GPLv2 or any later for new code. Probably
> netdb.c or pick a better name that you like.

This request leaves me with a lot of choices. I made them, but I guess
you will have something to say about it. See v3.

> 
> > +bool nft_getprotobynumber(int proto, char *out_name, size_t
> > name_len)
> > +{
> > +       const struct protoent *result;
> > +
> > +#if HAVE_DECL_GETPROTOBYNUMBER_R
> > +       struct protoent result_buf;
> > +       char buf[2048];
> > +       int r;
> > +
> > +       r = getprotobynumber_r(proto,
> > +                              &result_buf,
> > +                              buf,
> > +                              sizeof(buf),
> > +                              (struct protoent **) &result);
> > +       if (r != 0 || result != &result_buf)
> > +               result = NULL;
> > +#else
> > +       result = getprotobynumber(proto);
> > +#endif
> 
> I'd suggest wrap this code with #ifdef's in a helper function.

I don't understand. nft_getprotobynumber() *is* that helper function to
wrap the #if. This point is not addressed by v3 (??).



thanks,
Thomas