Re: ITS#3985 test039 hangs on Windows

[Howard Chu <hyc@symas.com>]

Kurt D. Zeilenga wrote:
> At 11:06 AM 10/7/2005, Howard Chu wrote:
>   
> > On the other hand, when exactly is it possible for a single request to have more than one result message?
> >     
>
> In LDAP, there can be many intermediate responses (as in a search
> entries, search references, and extended intermediate responses)
> to a single request, but only one of those responses contains
> the final result (as in searchResultDone).
>   

Yes, but none of those (search entry, search reference, or intermediate) 
responses are *Result* messages. Notice in libldap/error.c that it 
explicitly excludes those three response types when looking for Result 
messages. Since in fact the protocol only allows *one* Result message 
per Request, and every new Request gets its own msgID and its own place 
in the request queue, I conclude that LDAP_MORE_RESULTS_TO_RETURN is an 
impossible condition.
>   
> > Googling for LDAP_MORE_RESULTS_TO_RETURN shows that at least Sun/Netscape think this can only happen as the result of a SASL Bind request.
> > But there's nothing in the protocol spec (or LDAPbis drafts) that mentions this.
> >     
>
> LDAP_MORE_RESULTS_TO_RETURN is an API error, not a protocol result
> code, and hence not discussed in protocol specifications.
>   

I hoped some rationale would be in some IETF document somewhere. The 
note in the expired C API draft says it was added for LDAPv3 support.
> > It appears that this error code has no real application, and "Find the next result..." is wasted effort. What's really going on here?
> >     
>
> The API error is used in two places in libldap.  One
> in returning a SASL_CONTINUE condition and in
> ldap_parse_result() to indicate if more results are
> in the chain.
>   

Yes, in libldap/cyrus.c the sasl_err2ldap() function maps SASL_CONTINUE 
to LDAP_MORE_RESULTS_TO_RETURN. But if you check all (4) of the places 
where sasl_err2ldap() is called, you'll see that it is impossible for 
SASL_CONTINUE to ever be input to this function. So again, that's a red 
herring.

And in ldap_parse_result in libldap/error.c, as I've already pointed 
out, we queue responses with their originating requests. Any LDAP 
Request can only have one Result message, regardless of how many 
intermediate messages may be included. So it appears that all 
accomodation for this LDAP_MORE_RESULTS_TO_RETURN error code is just 
excess baggage.

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