added error diagnostics to find out where the connection is closed.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@5434 71c3de6d-444a-0410-be80-ed276b4c234a

remoting/src/main/java/hudson/remoting/Channel.java

@@ -370,7 +370,7 @@ public class Channel implements VirtualChannel {
         protected void execute(Channel channel) {
             try {
                 channel.close();
-                channel.terminate(null);
+                channel.terminate(new OrderlyShutdown(createdAt));
             } catch (IOException e) {
                 logger.log(Level.SEVERE,"close command failed on "+channel.name,e);
                 logger.log(Level.INFO,"close command created at",createdAt);
@@ -382,6 +382,18 @@ public class Channel implements VirtualChannel {
         }
     }
 
+    /**
+     * Signals the orderly shutdown of the channel, but captures
+     * where the termination was initiated as a nested exception.
+     */
+    private static final class OrderlyShutdown extends IOException {
+        private OrderlyShutdown(Throwable cause) {
+            super(cause.getMessage());
+            initCause(cause);
+        }
+        private static final long serialVersionUID = 1L;
+    }
+
     /**
      * {@inheritDoc}
      */