| /* |
| * Copyright (c) 2017, 2019, 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 UnreferencedSockets |
| * @run main/othervm -Djava.net.preferIPv4Stack=true UnreferencedSockets |
| * @summary Check that unreferenced sockets are closed |
| */ |
| |
| import java.io.FileDescriptor; |
| import java.io.InputStream; |
| import java.io.OutputStream; |
| 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.InetAddress; |
| import java.net.ServerSocket; |
| import java.net.Socket; |
| import java.net.SocketImpl; |
| 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 UnreferencedSockets { |
| |
| /** |
| * The set of sockets we have to check up on. |
| */ |
| final static ArrayDeque<NamedWeak> pendingSockets = new ArrayDeque<>(100); |
| |
| /** |
| * Queued sockets when they are unreferenced. |
| */ |
| final static ReferenceQueue<Object> pendingQueue = new ReferenceQueue<>(); |
| |
| // Server to echo a stream |
| static class Server implements Runnable { |
| |
| ServerSocket ss; |
| |
| Server(InetAddress address) throws IOException { |
| ss = new ServerSocket(0, 0, address); |
| pendingSockets.add(new NamedWeak(ss, pendingQueue, "serverSocket")); |
| extractRefs(ss, "serverSocket"); |
| } |
| |
| public int localPort() { |
| return ss.getLocalPort(); |
| } |
| |
| public void run() { |
| try { |
| Socket s = ss.accept(); |
| pendingSockets.add(new NamedWeak(s, pendingQueue, "acceptedSocket")); |
| extractRefs(s, "acceptedSocket"); |
| |
| InputStream in = s.getInputStream(); |
| int b = in.read(); |
| OutputStream out = s.getOutputStream(); |
| out.write(b); |
| // do NOT close but 'forget' the socket reference |
| out = null; |
| in = null; |
| s = null; |
| } catch (Exception ioe) { |
| ioe.printStackTrace(); |
| } finally { |
| try { |
| ss.close(); |
| ss = null; |
| } catch (IOException x) { |
| x.printStackTrace(); |
| } |
| } |
| } |
| } |
| |
| public static void main(String args[]) throws Exception { |
| |
| InetAddress lba = InetAddress.getLoopbackAddress(); |
| // Create and close a ServerSocket to warm up the FD count for side effects. |
| try (ServerSocket s = new ServerSocket(0, 0, lba)) { |
| // no-op; close immediately |
| s.getLocalPort(); // no-op |
| } |
| |
| long fdCount0 = getFdCount(); |
| listProcFD(); |
| |
| // start a server |
| Server svr = new Server(lba); |
| Thread thr = new Thread(svr); |
| thr.start(); |
| |
| Socket s = new Socket(lba, svr.localPort()); |
| pendingSockets.add(new NamedWeak(s, pendingQueue, "clientSocket")); |
| extractRefs(s, "clientSocket"); |
| |
| OutputStream out = s.getOutputStream(); |
| out.write('x'); |
| out.flush(); |
| InputStream in = s.getInputStream(); |
| int b = in.read(); // wait for it back |
| System.out.printf(" data sent and received%n"); |
| // Do NOT close the Socket; 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 queued: %s, remaining: %d%n", ref, pendingSockets.size()); |
| } else { |
| s = null; |
| out = null; |
| in = 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(Socket s, String name) { |
| try { |
| |
| Field socketImplField = Socket.class.getDeclaredField("impl"); |
| socketImplField.setAccessible(true); |
| Object socketImpl = socketImplField.get(s); |
| |
| Field fileDescriptorField = SocketImpl.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.getClass().getName().equals("java.net.TwoStacksPlainSocketImpl")) { |
| Field fileDescriptor1Field = socketImplClass.getDeclaredField("fd1"); |
| fileDescriptor1Field.setAccessible(true); |
| FileDescriptor fileDescriptor1 = (FileDescriptor) fileDescriptor1Field.get(socketImpl); |
| extractRefs(fileDescriptor1, name + "::twoStacksFd1"); |
| |
| } |
| } 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(" fd: %s, fd: %d, cleanup: %s%n", |
| fileDescriptor, rawfd, cleanup)); |
| } |
| } |
| |
| private static void extractRefs(ServerSocket s, String name) { |
| try { |
| |
| Field socketImplField = ServerSocket.class.getDeclaredField("impl"); |
| socketImplField.setAccessible(true); |
| Object socketImpl = socketImplField.get(s); |
| |
| Field fileDescriptorField = SocketImpl.class.getDeclaredField("fd"); |
| fileDescriptorField.setAccessible(true); |
| FileDescriptor fileDescriptor = (FileDescriptor) fileDescriptorField.get(socketImpl); |
| |
| Field fdField = FileDescriptor.class.getDeclaredField("fd"); |
| fdField.setAccessible(true); |
| int rawfd = fdField.getInt(fileDescriptor); |
| |
| Field cleanupField = FileDescriptor.class.getDeclaredField("cleanup"); |
| cleanupField.setAccessible(true); |
| Object cleanup = cleanupField.get(fileDescriptor); |
| |
| System.out.print(String.format(" fd: %s, fd: %d, cleanup: %s, socket: %s%n", |
| fileDescriptor, rawfd, cleanup, s)); |
| |
| 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); |
| } |
| } |
| |
| /** |
| * 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(); |
| } |
| } |
| } |