Re: ldap_str2dn() and ldap_dn2str() reentrant?

Michael Str=F6der wrote:
> Michael Str=F6der wrote:
>> Routinely in the C module part of python-ldap all calls to libldap fun=
ctions
>> are wrapped by a thread lock. But I wonder whether that's really neces=
sary for
>> all of them, especially regarding ldap_str2dn() and ldap_dn2str().
>
> Mainly for python-ldap this question boils down to whether ldap_bv2dn_x=
() and
> ldap_bv2rdn_x() are re-entrant. Glancing over these it seems they are
> re-entrant. But it would be nice if one of the OpenLDAP developers coul=
d
> confirm that.

*You're* an OpenLDAP developer... ;)

Yes, these functions are re-entrant. I would say most of libldap's functi=
ons=20
*don't* need any locking. The only really important thing is to call=20
ldap_init() once in the main program before any threads start, to make su=
re=20
that all of the global library options get parsed before threading occurs=
.=20
Beyond that, if you make sure that only one thread can use an LDAP handle=
 at a=20
time, there's no really re-entrancy issues to speak of.

Of course, there are no guarantees on underlying libraries that libldap u=
ses,=20
like SASL, OpenSSL, etc... If you need those features in a threaded progr=
am,=20
you need to use libldap_r because libldap doesn't do any thread initializ=
ation=20
for those other libraries.

--=20
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/