Re: 9.5: Can't connect with PGSSLMODE=require on Windows

On 2015-09-28 16:57:24 -0400, Tom Lane wrote:
> Asif Naeem <anaeem.it@gmail.com> writes:
> > I have spent sometime to investigate the issue, it is reproduciable. In
> > case of Windows, when pqsecure_raw_read() function error code
> > WSAEWOULDBLOCK (EWOULDBLOCK) when no data queued to be read from the non
> > blocking socket there is a need to log retry flag. Related error code can
> > be retrieved via Windows WSAGetLastError() instead of errno, preprocessor
> > SOCK_ERRNO handle it gracefully. PFA patch, it resolve the issue i.e.
> 
> > @@ -1601,7 +1601,7 @@ my_sock_read(BIO *h, char *buf, int size)
> >      int            save_errno;
> >  
> >      res = pqsecure_raw_read((PGconn *) h->ptr, buf, size);
> > -    save_errno = errno;
> > +    save_errno = SOCK_ERRNO;
> >      BIO_clear_retry_flags(h);
> >      if (res < 0)
> >      {
> 
> 
> Great detective work!  But if that's broken, then surely the identical
> code in my_sock_write is as well; and the reassignment to errno at the
> bottom of my_sock_read needs to be SOCK_ERRNO_SET(); and why doesn't
> my_sock_write have a reassignment at all?

I wonder if we couldn't remove saving/restoring errno entirely from
my_sock_*. We didn't do so before 680513ab79 and I can't see a reason
why we'd need to now.

What I do find curious is that afaics before 680513ab79 the code also
looked at errno, not SOCK_ERRNO. And apparently things worked back then?
I guess the difference is that pgsecure_raw_read now unconditionally
does SOCK_ERRNO_SET(result_errno).

Greetings,

Andres Freund