| /* |
| * Copyright (c) 1998, 2016, 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. |
| */ |
| |
| /* |
| */ |
| |
| import java.rmi.*; |
| import sun.rmi.transport.*; |
| import sun.rmi.*; |
| import java.io.*; |
| import java.lang.reflect.*; |
| import java.rmi.dgc.*; |
| import java.util.*; |
| import java.rmi.registry.*; |
| import java.rmi.server.*; |
| |
| public class TestImpl extends RegistryRunner |
| implements Test { |
| static Thread locker = null; |
| static TestImpl foo = null; |
| static TestImpl bar = null; |
| |
| TestImpl() throws RemoteException { |
| } |
| |
| public String echo(String msg) throws RemoteException { |
| |
| if (locker == null) { |
| // hold the target if not already held |
| locker = lockTargetExpireLeases(foo, DGCDeadLock.HOLD_TARGET_TIME); |
| } |
| return "Message received: " + msg; |
| } |
| |
| static public void main(String[] args) { |
| try { |
| int registryPort = RegistryRunner.init(args); |
| |
| //export "Foo" |
| foo = new TestImpl(); |
| Naming.rebind("rmi://:" + |
| registryPort |
| + "/Foo", foo); |
| |
| try { |
| //export "Bar" after leases have been expired. |
| bar = new TestImpl(); |
| Naming.rebind("rmi://localhost:" + |
| registryPort |
| + "/Bar", bar); |
| } catch (Exception e) { |
| throw new RemoteException(e.getMessage()); |
| } |
| |
| RegistryRunner.notify(registryPort); |
| } catch (Exception e) { |
| System.err.println(e.getMessage()); |
| e.printStackTrace(); |
| } |
| } |
| |
| static Thread lockTargetExpireLeases(Remote toLock, int timeOut) { |
| Thread t = new Thread((Runnable) new TargetLocker(toLock, timeOut)); |
| t.start(); |
| return t; |
| } |
| |
| static class TargetLocker implements Runnable { |
| |
| Remote toLock = null; |
| int timeOut = 0; |
| |
| TargetLocker(Remote toLock, int timeOut) { |
| this.toLock = toLock; |
| this.timeOut = timeOut; |
| } |
| |
| public void run() { |
| try { |
| // give dgc dirty calls time to finish. |
| Thread.currentThread().sleep(4000); |
| |
| java.security.AccessController. |
| doPrivileged(new LockTargetCheckLeases(toLock, |
| timeOut)); |
| |
| } catch (Exception e) { |
| System.err.println(e.getMessage()); |
| e.printStackTrace(); |
| System.exit(1); |
| } |
| } |
| } |
| |
| static class LockTargetCheckLeases |
| implements java.security.PrivilegedAction { |
| |
| Remote toLock = null; |
| int timeOut = 0; |
| |
| LockTargetCheckLeases(Remote toLock, int timeOut) { |
| this.toLock = toLock; |
| this.timeOut = timeOut; |
| } |
| |
| public Object run() { |
| try { |
| |
| Class args[] = new Class[1]; |
| |
| Class objTableClass = Class.forName |
| ("sun.rmi.transport.ObjectTable"); |
| |
| /* get the Target that corresponds to toLock from the |
| * ObjectTable |
| */ |
| args[0] = Class.forName("java.rmi.Remote"); |
| Method objTableGetTarget = |
| objTableClass.getDeclaredMethod("getTarget", args ); |
| objTableGetTarget.setAccessible(true); |
| |
| Target lockTarget = |
| ((Target) objTableGetTarget.invoke |
| (null , new Object [] {toLock} )); |
| |
| // make sure the lease on this object has expired. |
| expireLeases(lockTarget); |
| |
| // stop other threads from using the target for toLock. |
| synchronized (lockTarget) { |
| System.err.println("Locked the relevant target, sleeping " + |
| timeOut/1000 + " seconds"); |
| Thread.currentThread().sleep(timeOut); |
| System.err.println("Target unlocked"); |
| } |
| |
| } catch (Exception e) { |
| System.err.println(e.getMessage()); |
| e.printStackTrace(); |
| System.exit(1); |
| } |
| return null; |
| } |
| } |
| |
| /* leases have long values, so no dirty calls which would lock out |
| * a clean call, but the leases need to expire anyway, so we do it |
| * explicitly. |
| */ |
| static void expireLeases(Target t) throws Exception { |
| |
| final Target target = t; |
| |
| java.security.AccessController.doPrivileged( |
| |
| // put this into another class? |
| new java.security.PrivilegedAction() { |
| public Object run() { |
| try { |
| |
| Class DGCClass = Class.forName("sun.rmi.transport.DGCImpl"); |
| Method getDGCImpl = |
| DGCClass.getDeclaredMethod("getDGCImpl", null ); |
| getDGCImpl.setAccessible(true); |
| |
| // make sure the lease on this object has expired. |
| DGC dgcImpl = ((DGC) getDGCImpl.invoke(null, null)); |
| |
| /* Get the lease table from the DGCImpl. */ |
| Field reflectedLeaseTable = |
| dgcImpl.getClass().getDeclaredField("leaseTable"); |
| reflectedLeaseTable.setAccessible(true); |
| |
| Map leaseTable = (Map) reflectedLeaseTable.get(dgcImpl); |
| |
| // dont really need this synchronization... |
| synchronized (leaseTable) { |
| Iterator en = leaseTable.values().iterator(); |
| while (en.hasNext()) { |
| Object info = en.next(); |
| |
| /* Get the notifySet in the leaseInfo object. */ |
| Field notifySetField = |
| info.getClass().getDeclaredField("notifySet"); |
| notifySetField.setAccessible(true); |
| HashSet notifySet = (HashSet) notifySetField.get(info); |
| |
| Iterator iter = notifySet.iterator(); |
| while (iter.hasNext()) { |
| Target notified = (Target) iter.next(); |
| |
| if (notified == target) { |
| |
| /* Get and set the expiration field from the info object. */ |
| Field expirationField = info.getClass(). |
| getDeclaredField("expiration"); |
| expirationField.setAccessible(true); |
| expirationField.setLong(info, 0); |
| } |
| } |
| } |
| } |
| } catch (Exception e) { |
| System.err.println(e.getMessage()); |
| e.printStackTrace(); |
| System.exit(1); |
| } |
| // no interesting return value for this privileged action |
| return null; |
| } |
| }); |
| } |
| } |