Re: libldap_r thread-safety problems

[Howard Chu <hyc@symas.com>]

Emmanuel Dreyfus wrote:
> Hello
>
> I have thread-safety problems with libldap_r. My program uses libcurl to
> access a LDAP URL. When I attempt to fetch LDAP URL from multiple
> threads at once, I crash.
>
> I suspect there could be thread-safety issues with libldap_r. for
> instance, a nm shows it references gethostbyname, and not gethostname_r.
> Does it has any chance to be thread-safe if it uses gethostbyname?

The configure script checks for reentrant interfaces like 
gethostbyname_r. If it didn't find them, then libldap_r will use mutexes 
to protect the non-reentrant functions. Note that gethostname is not the 
same as gethostbyname.

If your version of libldap_r is not using the re-entrant APIs then 
something went wrong during configure to prevent it from finding those 
APIs. You should check your config.log...

That aside, libldap_r is (intentionally) undocumented; you use it at 
your own risk. We've made it reliable enough for slapd's purposes. If 
you're using it in any way differently from how slapd uses it, you're on 
your own.
--
  -- Howard Chu
  Chief Architect, Symas Corp.  http://www.symas.com
  Director, Highland Sun        http://highlandsun.com/hyc
  Chief Architect, OpenLDAP     http://www.openldap.org/project/