I fixed this (apparently) by adding "eval {local $SIG{ALRM}=sub {die}}"
blocks around the LDAP searches, with an alarm timer equal to the
user-specified LDAP timeout value. If the search doesn't come back on its
own, the code kicks in, and if the hang was fatal it barfs up a return 0
which allows me to exit gracefully. No problems since.
On 5/17/2005 5:18 PM, Eric A. Hall wrote:
> What's the recommended method for testing to see if a search has produced
> any results?
>
> I've got a strange problem and I'm pretty certain that there's some kind
> of synchronization issue between my search and reads.
>
> In more detail and for background information, I'm working on an
> LDAP-based blacklist plugin for SpamAssassin. By default, the plugin runs
> in a non-persistent mode, such that new LDAP sessions are established for
> each incoming message, queries are run, and the session is destroyed. This
> all seems to work pretty well, but its a lot of sessions to deal with.
>
> For efficiency I am trying to get the processes to run in persistent mode,
> so that a daemonized instance of SA can reuse a single LDAP session for
> the lifetime of that process (each instance of SA gets its own session).
> This seems to work for a little while, but eventually it develops a
> timeout condition where the LDAP search results don't get caught, so the
> plugin hangs which causes a cascade of timeout-related problems. My
> current (development) code has:
>
> #
> # issue the LDAP search
> #
> $permsgstatus->{ldap_search_result} = $self->{ldap_session}->search(
> base => $self->{ldap_search_base},
> filter => $permsgstatus->{ldap_search_filter},
> scope => $self->{ldap_search_scope},
> deref => $self->{ldap_search_deref},
> timelimit => $self->{ldap_timeout},
> attrs => [$permsgstatus->{ldap_resource_attr}]);
>
> #
> # see if there was a problem
> #
> if ((! defined $permsgstatus->{ldap_search_result}) ||
> ($permsgstatus->{ldap_search_result}->error ne "Success")) {
>
> #
> # report the error if it's defined
> #
> if (defined $permsgstatus->{ldap_search_result}) {
>
> dbg ("ldapBlacklist\: search failed with \"" .
> $permsgstatus->{ldap_search_result}->error . "\"");
> }
>
> #
> # disconnect the session politely
> #
> dbg ("ldapBlacklist\: unable to proceed " .
> "... terminating");
>
> $self->destroy_ldap_session($permsgstatus);
>
> #
> # kill the module so that nothing more happens
> #
> die;
> }
>
> I'm not getting any hits on this when persistency is enabled and when a
> failure occurs. I checked the LDAP logs and the queries are definitely
> getting processed, so my guess here is that I'm running into some kind of
> synchronization problem and I need to wait for the query to be answered or
> errored as appropriate.
>
> Any suggestions here?
>
> Thanks
