Re: [PATCH 4/4] New configure option --disable-crypt.

[Florian Weimer <fweimer at redhat dot com>]

On 06/21/2018 12:47 AM, Zack Weinberg wrote:
> On Wed, Jun 20, 2018 at 4:40 PM, Florian Weimer <fweimer@redhat.com> wrote:
> > On 05/22/2018 12:34 AM, Joseph Myers wrote:
> > > On Mon, 21 May 2018, Zack Weinberg wrote:
> > > > No, this is an intentional deviation from the present state of POSIX,
> > > > anticipating the removal of those functions from the standard.
> > >
> > > That would only seem relevant to the _XOPEN_CRYPT value in future POSIX
> > > modes, not current ones.
> >
> > So we should stop defining _XOPEN_CRYPT, but continue to declare crypt in
> > <unistd.h> for __USE_MISC || __USE_XOPEN?  That would work for me.
>
> Again, I think that it is inappropriate to stop defining _XOPEN_CRYPT
> in any mode.  Yes, this is an intentional deviation from POSIX, but I
> think it is far less likely to break existing programs than the
> alternative.

How can we resolve this conflict?

We have mostly cleaned up Fedora 28 to build with !_XOPEN_CRYPT already. 
 There weren't many changes AFAICS, and they fall broadly into two 
categories:

(1) Not including <crypt.h> for the crypt function, only <unistd.h>.
(2) Using DES functions.

(1) was far more common than (2).

We'll keep the declaration of crypt in <unistd.h> for _DEFAULT_SOURCE, 
so (1) will not be a problem.  (2) will not be addressed independently 
of the definition of _XOPEN_CRYPT.

This is why I'm fine with Joseph's approach.  It may even make it 
marginally easier to check whether you need your own DES implementation.

I would like to see a decision soon because I'm wondering if I have to 
back out the libxcrypt switch.

Thanks,
Florian