Re: (ITS#8638) Recursive mutex in libldap_r

[hyc@symas.com]

hyc@symas.com wrote:
> ondra@mistotebe.net wrote:
>>> IMO using recursive mutexes means your code is broken. We introduced these for
>>> accesslog.c but in fact we could avoid them at zero cost. Also I don't see the
>>> relevance of libevent to this discussion. We use our own event mechanism and
>>> it is more efficient than libevent.
>>
>> libevent is a dependency for the load balancer that I intend to propose
>> for integration into the project after all the relevant dependencies
>> have come in.
>>
>> There is a new version of this patch that provides an implementation on
>> each platform or defers to the existing one (as per each platform's
>> documentation). Untested except on POSIX and most of them seem pretty
>> arcane anyway.
>>
>> ftp://ftp.openldap.org/incoming/Ondrej-Kuznik-20170918-ITS8638-libldap_r-recursive-mutex.patch
>>
> It looks like glibc still doesn't define PTHREAD_MUTEX_RECURSIVE by default,
> it requires compiling with either -D_GNU_SOURCE or -D_XOPEN_SOURCE. The
> feature itself appears to be part of UNIX98. It's likely that all pthread
> implementations available today support it, but it still seems a bit iffy.
> 
OK, I see that current glibc defaults to _POSIX_C_SOURCE=200809 which includes 
__XOPEN_2K8. All of this came later than our rmutex.c which was written in 
2006, so that explains where the need arose from. We should be safe pushing 
this in, go ahead.

-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/