155186 – java/openjdk7: False exception throw by NetworkInterface.isUp() (and probably others)

NetworkInterface.isUp() can throw a SocketException when there was in
fact no error. This breaks, for example, JGroups.

getFlags in
/usr/ports/java/openjdk7/work/openjdk/jdk/src/solaris/native/java/net/NetworkInterface.c
returns if2.ifr_flags where if2 is a struct ifreq. Callers expect a
negative (int) result on error, a positive one otherwise. ifr_flags is
a short and the top bit can be set of multi-cast capable interfaces.
This remains negative when cast to an int and the caller believes an
error occurred. An exception is thrown based on whatever errno happens
to be.

My JDK port version is openjdk-7.0.122

Fix: 

Change the last statement of getFlags to 'return ((int) if2.ifr_flags) & 0xffff;'
How-To-Repeat: Run this (from JGroups):

import java.net.*;
import java.util.*;

public class test {
    public static void main(String[] argv) throws SocketException {
        InetAddress address=null ;

        try {
            Enumeration intfs=NetworkInterface.getNetworkInterfaces();
            while(intfs.hasMoreElements()) {
                NetworkInterface intf=(NetworkInterface)intfs.nextElement();
                if(intf.isUp()) {
                    //address=getAddress(intf, AddressScope.NON_LOOPBACK) ;
                    //System.err.println(address);
                }
            }
        } catch (SocketException e) {
            e.printStackTrace();
        }
    }
}