[PATCH] Add thread safety to socket_wrapper

[Jeremy Allison]

On Thu, Feb 22, 2018 at 12:30:16PM +0100, Volker Lendecke via samba-technical wrote:
> On Thu, Feb 22, 2018 at 12:03:11PM +0100, Andreas Schneider via samba-technical wrote:
> > On Thursday, 22 February 2018 11:46:36 CET Volker Lendecke wrote:
> > > On Thu, Feb 22, 2018 at 11:28:30AM +0100, Andreas Schneider via samba-
> > technical wrote:
> > > > the attached patchset adds thread safety support to socket_wrapper. It is
> > > > the ground work for fd passing to test multichannel and smbdirect in
> > > > selftest.
> > > > 
> > > > It would be great to get additional review. If I don't hear anything till
> > > > next week Wednesday I'm going to push it.
> > > 
> > > Not that it's relevant for the cwrap project, still my 2ct:
> > > 
> > > What's the point of SOCKET_INFO_GET_REFCOUNT? It's even more
> > > characters in source code. Also, SOCKET_INFO_GET hides the reference
> > > to a global variable. Why? These macros make the code harder to read,
> > > at least for me. Macros can have their place, but what's the reasoning
> > > here?
> > 
> > we implemented it that way, that in future steps, we just have to change 
> > SOCKET_INFO_GET() and not modify the complete source code again and again. We 
> > wanted to keep changes minimal if possible. Yes, currently it is a global 
> > variable but that will change. I hope our TODO list (appended at the end) 
> > helps you to understand the master plan behind it.
> 
> To me, helper functions are always preferrable. They give improved
> error checking, and less hassle with variable name conflicts. See
> https://en.wikipedia.org/wiki/Hygienic_macro for info on that. C in
> contrast to scheme just does not have hygienic macros. Helper
> functions also allow for anonymous structures when added to a separate
> module.

Andreas, I have to admit, moving the macro's to functions
would make much more sense, and also prevent erroneous
use of the macro's (functions at least will do argument
type checking).

If you don't have time, I might have a go at changing this
patchset to function rather than macro based code.

For long-term maintanence, it really is a better choice.

Jeremy