On Tue, Sep 03, 2013 at 02:12:01PM +0200, Jakub Hrozek wrote:
On Tue, Sep 03, 2013 at 10:29:57AM +0200, Lukas Slebodnik wrote:
> On (02/09/13 22:55), Jakub Hrozek wrote:
> >On Mon, Sep 02, 2013 at 03:20:12PM -0400, Simo Sorce wrote:
> >> On Mon, 2013-09-02 at 19:18 +0200, Lukas Slebodnik wrote:
> >> > ehlo,
> >> >
> >> > Some platforms can have defined SIZE_T_MAX.
> >> > It is better to use conditional build.
> >> >
> >> > Two patches are attached. one for master(1.10) and second for 1.9
> >>
> >>
> >> Uhmm defining SIZE_T_MAX as (size_t)-1 is not technically correct, it
> >> may work with gcc, but could fail with an optimizer, as -1 is simply an
> >> illegal value for an unsigned quantity.
> >>
> >> We should use the actual maximum value here.
> >>
> >> Simo.
> >
> >tl;dr - I think we should simply use SIZE_MAX instead.
> >
> >I actually think Lukas' patch *improves* the code. It seems that the
> >non-patched code defined SIZE_T_MAX no matter what. Lukas simply wraps
> >the macro #define in an #ifdef so if a platform defined SIZE_T_MAX in
> >some kind of system wide header, the definition would be picked up.
> >
> >But the real question I see is why did we ever use SIZE_T_MAX where we
> >should have used SIZE_MAX ? The standard says (7.18.3) that size_t
> >maximum value is SIZE_MAX with the minimum value set to 65535 where
> >implementations can choose larger values.
> >
> >Also, what problem do you see with (size_t)-1 ? As far as I see, this
> >is the recommended approach. The only alternative I can think of is ~0
> >but in several discussions (on comp.lang.c.moderated) this was considered
> >unsafe on some machines.
>
> I agree with SIZE_MAX.
> Here is part of header file stdint.h
> /* Limit of `size_t' type. */
> # if __WORDSIZE == 64
> # define SIZE_MAX (18446744073709551615UL)
> # else
> # define SIZE_MAX (4294967295U)
> # endif
>
> New patches attached and subject is also changed.
>
> LS
Yep, that aligns with some testing I did yesterday. Since overflows are
still being tested with unit tests, I think the patch is fine.
ACK.
Pushed to master, sssd-1-10 and sssd-1-9