Name: krC82822 Date: 02/01/2001


java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0)
Java HotSpot(TM) Client VM (build 1.3.0, mixed mode)

When you try to create any subclass of InitialContext, and connect it to (in our
case) an LDAP server which happens to be listening, but non responsive, the
constructor for InitialContext() will hang FOREVER. Timeouts can be specified
for searches, but NOT when first binding to the LDAP server.

We first observed this when our LDAP directory kept responding to connection
requests, but was badly wedged, and would not respond with the proper protocol.
I turned on the JNDI option to trace the BER packets going forth, and see the
first set of packets going to the non-responsive-but-still-listening directory.

The problem can be easily reproduced by trying to constructing an initial
context that connects to the standard Unix DISCARD server, on port 9.
The discard server does an excellent job of mimicing a down LDAP server, because
it accepts the connection, swallows the input and does nothing else. In other
words, it's not just a function of LDAP or a directory service...it's something
that exists at the base InitialContext class.

All I want to do is to put an initial timeout of x seconds on the context
constructor. If I can't establish the connection in that period of time, I want
my application to bail.

I know under the hood there is a socket connection
being made (looked at output of "truss java HangingContext", and saw
socket stuff), but I don't know how to get access to that socket to control it.

Nor have I found a way to set default timeout parameters for all upcoming client
sockets made in this application (I didn't think such a thing existed, but it
was worth looking.

Can I somehow get access to the underlying socket that
is making the connection to the LDAP server and alter its timeout
features???

Can I put the connection in an auxiliary thread, and run a timer which tries to
interrupt the auxiliary thread? Send a signal to the underlying socket?

Any other clever hacks out there?

----------------------------------------------------------

Sample code to reproduce

import javax.naming.*;
import java.util.*;

//connect to the discard server running on port 9 of a Unix box to
//demonstrate how to make the context call hang


class HangingContext {


    
    public static void main(String[] args) {

        // Retrieve any jndi environment properties from system properties.


        try {
            System.err.println(new Date().toString() + " about to connect");
            Context ctx = new InitialContext();
            System.err.println(new Date().toString() + " back from connect");
            ctx.close();
            
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

----

jndi.properties

java.naming.factory.initial=com.sun.jndi.ldap.LdapCtxFactory
java.naming.provider.url=ldap://<your host running the discard server>:9
(Review ID: 116211)
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