/*
* Copyright (c) 1997, 2006, 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* 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.
*
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package sun.rmi.server;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.net.ServerSocket;
import java.rmi.MarshalledObject;
import java.rmi.NoSuchObjectException;
import java.rmi.Remote;
import java.rmi.RemoteException;
import java.rmi.activation.Activatable;
import java.rmi.activation.ActivationDesc;
import java.rmi.activation.ActivationException;
import java.rmi.activation.ActivationGroup;
import java.rmi.activation.ActivationGroupID;
import java.rmi.activation.ActivationID;
import java.rmi.activation.UnknownObjectException;
import java.rmi.server.RMIClassLoader;
import java.rmi.server.RMIServerSocketFactory;
import java.rmi.server.RMISocketFactory;
import java.rmi.server.UnicastRemoteObject;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import sun.rmi.registry.RegistryImpl;
/**
* The default activation group implementation.
*
* @author Ann Wollrath
* @since 1.2
* @see java.rmi.activation.ActivationGroup
*/
public class ActivationGroupImpl extends ActivationGroup {
// use serialVersionUID from JDK 1.2.2 for interoperability
private static final long serialVersionUID = 5758693559430427303L;
/** maps persistent IDs to activated remote objects */
private final Hashtable<ActivationID,ActiveEntry> active =
new Hashtable<>();
private boolean groupInactive = false;
private final ActivationGroupID groupID;
private final List<ActivationID> lockedIDs = new ArrayList<>();
/**
* Creates a default activation group implementation.
*
* @param id the group's identifier
* @param data ignored
*/
public ActivationGroupImpl(ActivationGroupID id, MarshalledObject<?> data)
throws RemoteException
{
super(id);
groupID = id;
/*
* Unexport activation group impl and attempt to export it on
* an unshared anonymous port. See 4692286.
*/
unexportObject(this, true);
RMIServerSocketFactory ssf = new ServerSocketFactoryImpl();
UnicastRemoteObject.exportObject(this, 0, null, ssf);
if (System.getSecurityManager() == null) {
try {
// Provide a default security manager.
System.setSecurityManager(new SecurityManager());
} catch (Exception e) {
throw new RemoteException("unable to set security manager", e);
}
}
}
/**
* Trivial server socket factory used to export the activation group
* impl on an unshared port.
*/
private static class ServerSocketFactoryImpl
implements RMIServerSocketFactory
{
public ServerSocket createServerSocket(int port) throws IOException
{
RMISocketFactory sf = RMISocketFactory.getSocketFactory();
if (sf == null) {
sf = RMISocketFactory.getDefaultSocketFactory();
}
return sf.createServerSocket(port);
}
}
/*
* Obtains a lock on the ActivationID id before returning. Allows only one
* thread at a time to hold a lock on a particular id. If the lock for id
* is in use, all requests for an equivalent (in the Object.equals sense)
* id will wait for the id to be notified and use the supplied id as the
* next lock. The caller of "acquireLock" must execute the "releaseLock"
* method" to release the lock and "notifyAll" waiters for the id lock
* obtained from this method. The typical usage pattern is as follows:
*
* try {
* acquireLock(id);
* // do stuff pertaining to id...
* } finally {
* releaseLock(id);
* checkInactiveGroup();
* }
*/
private void acquireLock(ActivationID id) {
ActivationID waitForID;
for (;;) {
synchronized (lockedIDs) {
int index = lockedIDs.indexOf(id);
if (index < 0) {
lockedIDs.add(id);
return;
} else {
waitForID = lockedIDs.get(index);
}
}
synchronized (waitForID) {
synchronized (lockedIDs) {
int index = lockedIDs.indexOf(waitForID);
if (index < 0) continue;
ActivationID actualID = lockedIDs.get(index);
if (actualID != waitForID)
/*
* don't wait on an id that won't be notified.
*/
continue;
}
try {
waitForID.wait();
} catch (InterruptedException ignore) {
}
}
}
}
/*
* Releases the id lock obtained via the "acquireLock" method and then
* notifies all threads waiting on the lock.
*/
private void releaseLock(ActivationID id) {
synchronized (lockedIDs) {
id = lockedIDs.remove(lockedIDs.indexOf(id));
}
synchronized (id) {
id.notifyAll();
}
}
/**
* Creates a new instance of an activatable remote object. The
* <code>Activator</code> calls this method to create an activatable
* object in this group. This method should be idempotent; a call to
* activate an already active object should return the previously
* activated object.
*
* Note: this method assumes that the Activator will only invoke
* newInstance for the same object in a serial fashion (i.e.,
* the activator will not allow the group to see concurrent requests
* to activate the same object.
*
* @param id the object's activation identifier
* @param desc the object's activation descriptor
* @return a marshalled object containing the activated object's stub
*/
public MarshalledObject<? extends Remote>
newInstance(final ActivationID id,
final ActivationDesc desc)
throws ActivationException, RemoteException
{
RegistryImpl.checkAccess("ActivationInstantiator.newInstance");
if (!groupID.equals(desc.getGroupID()))
throw new ActivationException("newInstance in wrong group");
try {
acquireLock(id);
synchronized (this) {
if (groupInactive == true)
throw new InactiveGroupException("group is inactive");
}
ActiveEntry entry = active.get(id);
if (entry != null)
return entry.mobj;
String className = desc.getClassName();
final Class<? extends Remote> cl =
RMIClassLoader.loadClass(desc.getLocation(), className)
.asSubclass(Remote.class);
Remote impl = null;
final Thread t = Thread.currentThread();
final ClassLoader savedCcl = t.getContextClassLoader();
ClassLoader objcl = cl.getClassLoader();
final ClassLoader ccl = covers(objcl, savedCcl) ? objcl : savedCcl;
/*
* Fix for 4164971: allow non-public activatable class
* and/or constructor, create the activatable object in a
* privileged block
*/
try {
/*
* The code below is in a doPrivileged block to
* protect against user code which code might have set
* a global socket factory (in which case application
* code would be on the stack).
*/
impl = AccessController.doPrivileged(
new PrivilegedExceptionAction<Remote>() {
public Remote run() throws InstantiationException,
NoSuchMethodException, IllegalAccessException,
InvocationTargetException
{
Constructor<? extends Remote> constructor =
cl.getDeclaredConstructor(
ActivationID.class, MarshalledObject.class);
constructor.setAccessible(true);
try {
/*
* Fix for 4289544: make sure to set the
* context class loader to be the class
* loader of the impl class before
* constructing that class.
*/
t.setContextClassLoader(ccl);
return constructor.newInstance(id,
desc.getData());
} finally {
t.setContextClassLoader(savedCcl);
}
}
});
} catch (PrivilegedActionException pae) {
Throwable e = pae.getException();
// narrow the exception's type and rethrow it
if (e instanceof InstantiationException) {
throw (InstantiationException) e;
} else if (e instanceof NoSuchMethodException) {
throw (NoSuchMethodException) e;
} else if (e instanceof IllegalAccessException) {
throw (IllegalAccessException) e;
} else if (e instanceof InvocationTargetException) {
throw (InvocationTargetException) e;
} else if (e instanceof RuntimeException) {
throw (RuntimeException) e;
} else if (e instanceof Error) {
throw (Error) e;
}
}
entry = new ActiveEntry(impl);
active.put(id, entry);
return entry.mobj;
} catch (NoSuchMethodException | NoSuchMethodError e) {
/* user forgot to provide activatable constructor?
* or code recompiled and user forgot to provide
* activatable constructor?
*/
throw new ActivationException
("Activatable object must provide an activation"+
" constructor", e );
} catch (InvocationTargetException e) {
throw new ActivationException("exception in object constructor",
e.getTargetException());
} catch (Exception e) {
throw new ActivationException("unable to activate object", e);
} finally {
releaseLock(id);
checkInactiveGroup();
}
}
/**
* The group's <code>inactiveObject</code> method is called
* indirectly via a call to the <code>Activatable.inactive</code>
* method. A remote object implementation must call
* <code>Activatable</code>'s <code>inactive</code> method when
* that object deactivates (the object deems that it is no longer
* active). If the object does not call
* <code>Activatable.inactive</code> when it deactivates, the
* object will never be garbage collected since the group keeps
* strong references to the objects it creates. <p>
*
* The group's <code>inactiveObject</code> method
* unexports the remote object from the RMI runtime so that the
* object can no longer receive incoming RMI calls. This call will
* only succeed if the object has no pending/executing calls. If
* the object does have pending/executing RMI calls, then false
* will be returned.
*
* If the object has no pending/executing calls, the object is
* removed from the RMI runtime and the group informs its
* <code>ActivationMonitor</code> (via the monitor's
* <code>inactiveObject</code> method) that the remote object is
* not currently active so that the remote object will be
* re-activated by the activator upon a subsequent activation
* request.
*
* @param id the object's activation identifier
* @returns true if the operation succeeds (the operation will
* succeed if the object in currently known to be active and is
* either already unexported or is currently exported and has no
* pending/executing calls); false is returned if the object has
* pending/executing calls in which case it cannot be deactivated
* @exception UnknownObjectException if object is unknown (may already
* be inactive)
* @exception RemoteException if call informing monitor fails
*/
public boolean inactiveObject(ActivationID id)
throws ActivationException, UnknownObjectException, RemoteException
{
try {
acquireLock(id);
synchronized (this) {
if (groupInactive == true)
throw new ActivationException("group is inactive");
}
ActiveEntry entry = active.get(id);
if (entry == null) {
// REMIND: should this be silent?
throw new UnknownObjectException("object not active");
}
try {
if (Activatable.unexportObject(entry.impl, false) == false)
return false;
} catch (NoSuchObjectException allowUnexportedObjects) {
}
try {
super.inactiveObject(id);
} catch (UnknownObjectException allowUnregisteredObjects) {
}
active.remove(id);
} finally {
releaseLock(id);
checkInactiveGroup();
}
return true;
}
/*
* Determines if the group has become inactive and
* marks it as such.
*/
private void checkInactiveGroup() {
boolean groupMarkedInactive = false;
synchronized (this) {
if (active.size() == 0 && lockedIDs.size() == 0 &&
groupInactive == false)
{
groupInactive = true;
groupMarkedInactive = true;
}
}
if (groupMarkedInactive) {
try {
super.inactiveGroup();
} catch (Exception ignoreDeactivateFailure) {
}
try {
UnicastRemoteObject.unexportObject(this, true);
} catch (NoSuchObjectException allowUnexportedGroup) {
}
}
}
/**
* The group's <code>activeObject</code> method is called when an
* object is exported (either by <code>Activatable</code> object
* construction or an explicit call to
* <code>Activatable.exportObject</code>. The group must inform its
* <code>ActivationMonitor</code> that the object is active (via
* the monitor's <code>activeObject</code> method) if the group
* hasn't already done so.
*
* @param id the object's identifier
* @param obj the remote object implementation
* @exception UnknownObjectException if object is not registered
* @exception RemoteException if call informing monitor fails
*/
public void activeObject(ActivationID id, Remote impl)
throws ActivationException, UnknownObjectException, RemoteException
{
try {
acquireLock(id);
synchronized (this) {
if (groupInactive == true)
throw new ActivationException("group is inactive");
}
if (!active.contains(id)) {
ActiveEntry entry = new ActiveEntry(impl);
active.put(id, entry);
// created new entry, so inform monitor of active object
try {
super.activeObject(id, entry.mobj);
} catch (RemoteException e) {
// daemon can still find it by calling newInstance
}
}
} finally {
releaseLock(id);
checkInactiveGroup();
}
}
/**
* Entry in table for active object.
*/
private static class ActiveEntry {
Remote impl;
MarshalledObject<Remote> mobj;
ActiveEntry(Remote impl) throws ActivationException {
this.impl = impl;
try {
this.mobj = new MarshalledObject<Remote>(impl);
} catch (IOException e) {
throw new
ActivationException("failed to marshal remote object", e);
}
}
}
/**
* Returns true if the first argument is either equal to, or is a
* descendant of, the second argument. Null is treated as the root of
* the tree.
*/
private static boolean covers(ClassLoader sub, ClassLoader sup) {
if (sup == null) {
return true;
} else if (sub == null) {
return false;
}
do {
if (sub == sup) {
return true;
}
sub = sub.getParent();
} while (sub != null);
return false;
}
}