Re: [libvirt] [PATCH] remote: Fix TLS transport on Windows

2010/11/22 Eric Blake <eblake(a)redhat.com&gt;: > On 11/22/2010 01:42 PM, Matthias Bolte wrote: >>>> This doesn't entirely make any sense to me. GNUTLS also uses GNULIB, >>>> including all its socket wrappers for send/recv. If the push/pull >>>> function is NULL, gnulib does this >>>> >>>>      if (session->internals._gnutls_push_func == NULL) >>>>        { >>>>          i = send (GNUTLS_POINTER_TO_INT (fd), &ptr[n - left], left, 0); >>>> >> >> Okay, yes GnuTLS uses gnulib, but they explicitly don't use gnulib's >> replacements for send() and recv() on Windows. See >> lib/gnutls_buffers.c: >> >> /* We need to disable gnulib's replacement wrappers to get native >>    Windows interfaces. */ >> #undef recv >> #undef send >> >> GnuTLS decided to use the native Windows versions of send() and >> recv(). This cannot be changed, as that would break existing >> applications using GnuTLS on Windows relying on GnuTLS using the >> native Windows versions of send() and recv(). Therefore, I think my >> patch is necessary, as libvirt requires GnuTLS to use gnulib's >> replacement functions. > > Makes sense to me.  However, why the double cast? > > +#if HAVE_WINSOCK2_H > +static ssize_t > +custom_gnutls_push(void *s, const void *buf, size_t len) > +{ > +    return send((int)(long)s, buf, len, 0); > +} > + > +static ssize_t > +custom_gnutls_pull(void *s, void *buf, size_t len) > +{ > +    return recv((int)(long)s, buf, len, 0); > +} > +#endif > > Wouldn't send((size_t)s, ...) be better than send((int)(long)s,...)? > I just used what'a in curl, as directly casting from void* to int would give this error on 64bit platform: error: cast from pointer to integer of different size [-Wpointer-to-int-cast] (Yes, this is tested on Linux 64bit, as I didn't setup mingw-w64 yet) Casting to size_t works too. Here's a v2 that casts to size_t and has an improved commit message.