--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/net/MulticastSocket/UnreferencedMulticastSockets.java Fri Feb 02 14:17:07 2018 -0500
@@ -0,0 +1,271 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @modules java.management java.base/java.io:+open java.base/java.net:+open
+ * @run main/othervm -Djava.net.preferIPv4Stack=true UnreferencedMulticastSockets
+ * @run main/othervm UnreferencedMulticastSockets
+ * @summary Check that unreferenced multicast sockets are closed
+ */
+
+import java.io.FileDescriptor;
+import java.lang.management.ManagementFactory;
+import java.lang.management.OperatingSystemMXBean;
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.WeakReference;
+import java.lang.reflect.Field;
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.DatagramSocketImpl;
+import java.net.InetAddress;
+import java.net.MulticastSocket;
+import java.net.UnknownHostException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayDeque;
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.TimeUnit;
+
+import com.sun.management.UnixOperatingSystemMXBean;
+
+public class UnreferencedMulticastSockets {
+
+ /**
+ * The set of sockets we have to check up on.
+ */
+ final static ArrayDeque<NamedWeak> pendingSockets = new ArrayDeque<>(5);
+
+ /**
+ * Queued objects when they are unreferenced.
+ */
+ final static ReferenceQueue<Object> pendingQueue = new ReferenceQueue<>();
+
+ // Server to echo a datagram packet
+ static class Server implements Runnable {
+
+ MulticastSocket ss;
+
+ Server() throws IOException {
+ ss = new MulticastSocket(0);
+ System.out.printf(" DatagramServer addr: %s: %d%n",
+ this.getHost(), this.getPort());
+ pendingSockets.add(new NamedWeak(ss, pendingQueue, "serverMulticastSocket"));
+ extractRefs(ss, "serverMulticastSocket");
+ }
+
+ InetAddress getHost() throws UnknownHostException {
+ InetAddress localhost = InetAddress.getByName("localhost"); //.getLocalHost();
+ return localhost;
+ }
+
+ int getPort() {
+ return ss.getLocalPort();
+ }
+
+ // Receive a byte and send back a byte
+ public void run() {
+ try {
+ byte[] buffer = new byte[50];
+ DatagramPacket p = new DatagramPacket(buffer, buffer.length);
+ ss.receive(p);
+ buffer[0] += 1;
+ ss.send(p); // send back +1
+
+ // do NOT close but 'forget' the socket reference
+ ss = null;
+ } catch (Exception ioe) {
+ ioe.printStackTrace();
+ }
+ }
+ }
+
+ public static void main(String args[]) throws Exception {
+
+ // Create and close a MulticastSocket to warm up the FD count for side effects.
+ try (MulticastSocket s = new MulticastSocket(0)) {
+ // no-op; close immediately
+ s.getLocalPort(); // no-op
+ }
+
+ long fdCount0 = getFdCount();
+ listProcFD();
+
+ // start a server
+ Server svr = new Server();
+ Thread thr = new Thread(svr);
+ thr.start();
+
+ MulticastSocket client = new MulticastSocket(0);
+ client.connect(svr.getHost(), svr.getPort());
+ pendingSockets.add(new NamedWeak(client, pendingQueue, "clientMulticastSocket"));
+ extractRefs(client, "clientMulticastSocket");
+
+ byte[] msg = new byte[1];
+ msg[0] = 1;
+ DatagramPacket p = new DatagramPacket(msg, msg.length, svr.getHost(), svr.getPort());
+ client.send(p);
+
+ p = new DatagramPacket(msg, msg.length);
+ client.receive(p);
+
+ System.out.printf("echo received from: %s%n", p.getSocketAddress());
+ if (msg[0] != 2) {
+ throw new AssertionError("incorrect data received: expected: 2, actual: " + msg[0]);
+ }
+
+ // Do NOT close the MulticastSocket; forget it
+
+ Object ref;
+ int loops = 20;
+ while (!pendingSockets.isEmpty() && loops-- > 0) {
+ ref = pendingQueue.remove(1000L);
+ if (ref != null) {
+ pendingSockets.remove(ref);
+ System.out.printf(" ref freed: %s, remaining: %d%n", ref, pendingSockets.size());
+ } else {
+ client = null;
+ p = null;
+ msg = null;
+ System.gc();
+ }
+ }
+
+ thr.join();
+
+ // List the open file descriptors
+ long fdCount = getFdCount();
+ System.out.printf("Initial fdCount: %d, final fdCount: %d%n", fdCount0, fdCount);
+ listProcFD();
+
+ if (loops == 0) {
+ throw new AssertionError("Not all references reclaimed");
+ }
+ }
+
+ // Get the count of open file descriptors, or -1 if not available
+ private static long getFdCount() {
+ OperatingSystemMXBean mxBean = ManagementFactory.getOperatingSystemMXBean();
+ return (mxBean instanceof UnixOperatingSystemMXBean)
+ ? ((UnixOperatingSystemMXBean) mxBean).getOpenFileDescriptorCount()
+ : -1L;
+ }
+
+ // Reflect to find references in the socket implementation that will be gc'd
+ private static void extractRefs(MulticastSocket s, String name) {
+ try {
+
+ Field socketImplField = DatagramSocket.class.getDeclaredField("impl");
+ socketImplField.setAccessible(true);
+ Object socketImpl = socketImplField.get(s);
+
+ Field fileDescriptorField = DatagramSocketImpl.class.getDeclaredField("fd");
+ fileDescriptorField.setAccessible(true);
+ FileDescriptor fileDescriptor = (FileDescriptor) fileDescriptorField.get(socketImpl);
+ extractRefs(fileDescriptor, name);
+
+ Class<?> socketImplClass = socketImpl.getClass();
+ System.out.printf("socketImplClass: %s%n", socketImplClass);
+ if (socketImplClass.getName().equals("java.net.TwoStacksPlainDatagramSocketImpl")) {
+ Field fileDescriptor1Field = socketImplClass.getDeclaredField("fd1");
+ fileDescriptor1Field.setAccessible(true);
+ FileDescriptor fileDescriptor1 = (FileDescriptor) fileDescriptor1Field.get(socketImpl);
+ extractRefs(fileDescriptor1, name + "::twoStacksFd1");
+
+ } else {
+ System.out.printf("socketImpl class name not matched: %s != %s%n",
+ socketImplClass.getName(), "java.net.TwoStacksPlainDatagramSocketImpl");
+ }
+ } catch (NoSuchFieldException | IllegalAccessException ex) {
+ ex.printStackTrace();
+ throw new AssertionError("missing field", ex);
+ }
+ }
+
+ private static void extractRefs(FileDescriptor fileDescriptor, String name) {
+ Object cleanup = null;
+ int rawfd = -1;
+ try {
+ if (fileDescriptor != null) {
+ Field fd1Field = FileDescriptor.class.getDeclaredField("fd");
+ fd1Field.setAccessible(true);
+ rawfd = fd1Field.getInt(fileDescriptor);
+
+ Field cleanupfdField = FileDescriptor.class.getDeclaredField("cleanup");
+ cleanupfdField.setAccessible(true);
+ cleanup = cleanupfdField.get(fileDescriptor);
+ pendingSockets.add(new NamedWeak(fileDescriptor, pendingQueue,
+ name + "::fileDescriptor: " + rawfd));
+ pendingSockets.add(new NamedWeak(cleanup, pendingQueue, name + "::fdCleanup: " + rawfd));
+
+ }
+ } catch (NoSuchFieldException | IllegalAccessException ex) {
+ ex.printStackTrace();
+ throw new AssertionError("missing field", ex);
+ } finally {
+ System.out.print(String.format(" %s:: fd: %s, fd: %d, cleanup: %s%n",
+ name, fileDescriptor, rawfd, cleanup));
+ }
+ }
+
+ /**
+ * Method to list the open file descriptors (if supported by the 'lsof' command).
+ */
+ static void listProcFD() {
+ List<String> lsofDirs = List.of("/usr/bin", "/usr/sbin");
+ Optional<Path> lsof = lsofDirs.stream()
+ .map(s -> Paths.get(s, "lsof"))
+ .filter(f -> Files.isExecutable(f))
+ .findFirst();
+ lsof.ifPresent(exe -> {
+ try {
+ System.out.printf("Open File Descriptors:%n");
+ long pid = ProcessHandle.current().pid();
+ ProcessBuilder pb = new ProcessBuilder(exe.toString(), "-p", Integer.toString((int) pid));
+ pb.inheritIO();
+ Process p = pb.start();
+ p.waitFor(10, TimeUnit.SECONDS);
+ } catch (IOException | InterruptedException ie) {
+ ie.printStackTrace();
+ }
+ });
+ }
+
+
+ // Simple class to identify which refs have been queued
+ static class NamedWeak extends WeakReference<Object> {
+ private final String name;
+
+ NamedWeak(Object o, ReferenceQueue<Object> queue, String name) {
+ super(o, queue);
+ this.name = name;
+ }
+
+ public String toString() {
+ return name + "; " + super.toString();
+ }
+ }
+}