/*
* Copyright (c) 1996, 2011, 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.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package sun.rmi.server;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.PrintStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.rmi.MarshalException;
import java.rmi.Remote;
import java.rmi.RemoteException;
import java.rmi.ServerError;
import java.rmi.ServerException;
import java.rmi.UnmarshalException;
import java.rmi.server.ExportException;
import java.rmi.server.RemoteCall;
import java.rmi.server.RemoteRef;
import java.rmi.server.RemoteStub;
import java.rmi.server.ServerNotActiveException;
import java.rmi.server.ServerRef;
import java.rmi.server.Skeleton;
import java.rmi.server.SkeletonNotFoundException;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.WeakHashMap;
import sun.rmi.runtime.Log;
import sun.rmi.transport.LiveRef;
import sun.rmi.transport.Target;
import sun.rmi.transport.tcp.TCPTransport;
import sun.security.action.GetBooleanAction;
/**
* UnicastServerRef implements the remote reference layer server-side
* behavior for remote objects exported with the "UnicastRef" reference
* type.
*
* @author Ann Wollrath
* @author Roger Riggs
* @author Peter Jones
*/
public class UnicastServerRef extends UnicastRef
implements ServerRef, Dispatcher
{
/** value of server call log property */
public static final boolean logCalls = AccessController.doPrivileged(
new GetBooleanAction("java.rmi.server.logCalls"));
/** server call log */
public static final Log callLog =
Log.getLog("sun.rmi.server.call", "RMI", logCalls);
// use serialVersionUID from JDK 1.2.2 for interoperability
private static final long serialVersionUID = -7384275867073752268L;
/** flag to enable writing exceptions to System.err */
private static final boolean wantExceptionLog =
AccessController.doPrivileged(
new GetBooleanAction("sun.rmi.server.exceptionTrace"));
private boolean forceStubUse = false;
/**
* flag to remove server-side stack traces before marshalling
* exceptions thrown by remote invocations to this VM
*/
private static final boolean suppressStackTraces =
AccessController.doPrivileged(
new GetBooleanAction(
"sun.rmi.server.suppressStackTraces"));
/**
* skeleton to dispatch remote calls through, for 1.1 stub protocol
* (may be null if stub class only uses 1.2 stub protocol)
*/
private transient Skeleton skel;
/** maps method hash to Method object for each remote method */
private transient Map<Long,Method> hashToMethod_Map = null;
/**
* A weak hash map, mapping classes to hash maps that map method
* hashes to method objects.
**/
private static final WeakClassHashMap<Map<Long,Method>> hashToMethod_Maps =
new HashToMethod_Maps();
/** cache of impl classes that have no corresponding skeleton class */
private static final Map<Class<?>,?> withoutSkeletons =
Collections.synchronizedMap(new WeakHashMap<Class<?>,Void>());
/**
* Create a new (empty) Unicast server remote reference.
*/
public UnicastServerRef() {
}
/**
* Construct a Unicast server remote reference for a specified
* liveRef.
*/
public UnicastServerRef(LiveRef ref) {
super(ref);
}
/**
* Construct a Unicast server remote reference to be exported
* on the specified port.
*/
public UnicastServerRef(int port) {
super(new LiveRef(port));
}
/**
* Constructs a UnicastServerRef to be exported on an
* anonymous port (i.e., 0) and that uses a pregenerated stub class
* (NOT a dynamic proxy instance) if 'forceStubUse' is 'true'.
*
* This constructor is only called by the method
* UnicastRemoteObject.exportObject(Remote) passing 'true' for
* 'forceStubUse'. The UnicastRemoteObject.exportObject(Remote) method
* returns RemoteStub, so it must ensure that the stub for the
* exported object is an instance of a pregenerated stub class that
* extends RemoteStub (instead of an instance of a dynamic proxy class
* which is not an instance of RemoteStub).
**/
public UnicastServerRef(boolean forceStubUse) {
this(0);
this.forceStubUse = forceStubUse;
}
/**
* With the addition of support for dynamic proxies as stubs, this
* method is obsolete because it returns RemoteStub instead of the more
* general Remote. It should not be called. It sets the
* 'forceStubUse' flag to true so that the stub for the exported object
* is forced to be an instance of the pregenerated stub class, which
* extends RemoteStub.
*
* Export this object, create the skeleton and stubs for this
* dispatcher. Create a stub based on the type of the impl,
* initialize it with the appropriate remote reference. Create the
* target defined by the impl, dispatcher (this) and stub.
* Export that target via the Ref.
**/
public RemoteStub exportObject(Remote impl, Object data)
throws RemoteException
{
forceStubUse = true;
return (RemoteStub) exportObject(impl, data, false);
}
/**
* Export this object, create the skeleton and stubs for this
* dispatcher. Create a stub based on the type of the impl,
* initialize it with the appropriate remote reference. Create the
* target defined by the impl, dispatcher (this) and stub.
* Export that target via the Ref.
*/
public Remote exportObject(Remote impl, Object data,
boolean permanent)
throws RemoteException
{
Class implClass = impl.getClass();
Remote stub;
try {
stub = Util.createProxy(implClass, getClientRef(), forceStubUse);
} catch (IllegalArgumentException e) {
throw new ExportException(
"remote object implements illegal remote interface", e);
}
if (stub instanceof RemoteStub) {
setSkeleton(impl);
}
Target target =
new Target(impl, this, stub, ref.getObjID(), permanent);
ref.exportObject(target);
hashToMethod_Map = hashToMethod_Maps.get(implClass);
return stub;
}
/**
* Return the hostname of the current client. When called from a
* thread actively handling a remote method invocation the
* hostname of the client is returned.
* @exception ServerNotActiveException If called outside of servicing
* a remote method invocation.
*/
public String getClientHost() throws ServerNotActiveException {
return TCPTransport.getClientHost();
}
/**
* Discovers and sets the appropriate skeleton for the impl.
*/
public void setSkeleton(Remote impl) throws RemoteException {
if (!withoutSkeletons.containsKey(impl.getClass())) {
try {
skel = Util.createSkeleton(impl);
} catch (SkeletonNotFoundException e) {
/*
* Ignore exception for skeleton class not found, because a
* skeleton class is not necessary with the 1.2 stub protocol.
* Remember that this impl's class does not have a skeleton
* class so we don't waste time searching for it again.
*/
withoutSkeletons.put(impl.getClass(), null);
}
}
}
/**
* Call to dispatch to the remote object (on the server side).
* The up-call to the server and the marshalling of return result
* (or exception) should be handled before returning from this
* method.
* @param obj the target remote object for the call
* @param call the "remote call" from which operation and
* method arguments can be obtained.
* @exception IOException If unable to marshal return result or
* release input or output streams
*/
public void dispatch(Remote obj, RemoteCall call) throws IOException {
// positive operation number in 1.1 stubs;
// negative version number in 1.2 stubs and beyond...
int num;
long op;
try {
// read remote call header
ObjectInput in;
try {
in = call.getInputStream();
num = in.readInt();
if (num >= 0) {
if (skel != null) {
oldDispatch(obj, call, num);
return;
} else {
throw new UnmarshalException(
"skeleton class not found but required " +
"for client version");
}
}
op = in.readLong();
} catch (Exception readEx) {
throw new UnmarshalException("error unmarshalling call header",
readEx);
}
/*
* Since only system classes (with null class loaders) will be on
* the execution stack during parameter unmarshalling for the 1.2
* stub protocol, tell the MarshalInputStream not to bother trying
* to resolve classes using its superclasses's default method of
* consulting the first non-null class loader on the stack.
*/
MarshalInputStream marshalStream = (MarshalInputStream) in;
marshalStream.skipDefaultResolveClass();
Method method = hashToMethod_Map.get(op);
if (method == null) {
throw new UnmarshalException("unrecognized method hash: " +
"method not supported by remote object");
}
// if calls are being logged, write out object id and operation
logCall(obj, method);
// unmarshal parameters
Class[] types = method.getParameterTypes();
Object[] params = new Object[types.length];
try {
unmarshalCustomCallData(in);
for (int i = 0; i < types.length; i++) {
params[i] = unmarshalValue(types[i], in);
}
} catch (java.io.IOException e) {
throw new UnmarshalException(
"error unmarshalling arguments", e);
} catch (ClassNotFoundException e) {
throw new UnmarshalException(
"error unmarshalling arguments", e);
} finally {
call.releaseInputStream();
}
// make upcall on remote object
Object result;
try {
result = method.invoke(obj, params);
} catch (InvocationTargetException e) {
throw e.getTargetException();
}
// marshal return value
try {
ObjectOutput out = call.getResultStream(true);
Class rtype = method.getReturnType();
if (rtype != void.class) {
marshalValue(rtype, result, out);
}
} catch (IOException ex) {
throw new MarshalException("error marshalling return", ex);
/*
* This throw is problematic because when it is caught below,
* we attempt to marshal it back to the client, but at this
* point, a "normal return" has already been indicated,
* so marshalling an exception will corrupt the stream.
* This was the case with skeletons as well; there is no
* immediately obvious solution without a protocol change.
*/
}
} catch (Throwable e) {
logCallException(e);
ObjectOutput out = call.getResultStream(false);
if (e instanceof Error) {
e = new ServerError(
"Error occurred in server thread", (Error) e);
} else if (e instanceof RemoteException) {
e = new ServerException(
"RemoteException occurred in server thread",
(Exception) e);
}
if (suppressStackTraces) {
clearStackTraces(e);
}
out.writeObject(e);
} finally {
call.releaseInputStream(); // in case skeleton doesn't
call.releaseOutputStream();
}
}
protected void unmarshalCustomCallData(ObjectInput in)
throws IOException, ClassNotFoundException
{}
/**
* Handle server-side dispatch using the RMI 1.1 stub/skeleton
* protocol, given a non-negative operation number that has
* already been read from the call stream.
*
* @param obj the target remote object for the call
* @param call the "remote call" from which operation and
* method arguments can be obtained.
* @param op the operation number
* @exception IOException if unable to marshal return result or
* release input or output streams
*/
public void oldDispatch(Remote obj, RemoteCall call, int op)
throws IOException
{
long hash; // hash for matching stub with skeleton
try {
// read remote call header
ObjectInput in;
try {
in = call.getInputStream();
try {
Class<?> clazz = Class.forName("sun.rmi.transport.DGCImpl_Skel");
if (clazz.isAssignableFrom(skel.getClass())) {
((MarshalInputStream)in).useCodebaseOnly();
}
} catch (ClassNotFoundException ignore) { }
hash = in.readLong();
} catch (Exception readEx) {
throw new UnmarshalException("error unmarshalling call header",
readEx);
}
// if calls are being logged, write out object id and operation
logCall(obj, skel.getOperations()[op]);
unmarshalCustomCallData(in);
// dispatch to skeleton for remote object
skel.dispatch(obj, call, op, hash);
} catch (Throwable e) {
logCallException(e);
ObjectOutput out = call.getResultStream(false);
if (e instanceof Error) {
e = new ServerError(
"Error occurred in server thread", (Error) e);
} else if (e instanceof RemoteException) {
e = new ServerException(
"RemoteException occurred in server thread",
(Exception) e);
}
if (suppressStackTraces) {
clearStackTraces(e);
}
out.writeObject(e);
} finally {
call.releaseInputStream(); // in case skeleton doesn't
call.releaseOutputStream();
}
}
/**
* Clear the stack trace of the given Throwable by replacing it with
* an empty StackTraceElement array, and do the same for all of its
* chained causative exceptions.
*/
public static void clearStackTraces(Throwable t) {
StackTraceElement[] empty = new StackTraceElement[0];
while (t != null) {
t.setStackTrace(empty);
t = t.getCause();
}
}
/**
* Log the details of an incoming call. The method parameter is either of
* type java.lang.reflect.Method or java.rmi.server.Operation.
*/
private void logCall(Remote obj, Object method) {
if (callLog.isLoggable(Log.VERBOSE)) {
String clientHost;
try {
clientHost = getClientHost();
} catch (ServerNotActiveException snae) {
clientHost = "(local)"; // shouldn't happen
}
callLog.log(Log.VERBOSE, "[" + clientHost + ": " +
obj.getClass().getName() +
ref.getObjID().toString() + ": " +
method + "]");
}
}
/**
* Log the exception detail of an incoming call.
*/
private void logCallException(Throwable e) {
// if calls are being logged, log them
if (callLog.isLoggable(Log.BRIEF)) {
String clientHost = "";
try {
clientHost = "[" + getClientHost() + "] ";
} catch (ServerNotActiveException snae) {
}
callLog.log(Log.BRIEF, clientHost + "exception: ", e);
}
// write exceptions (only) to System.err if desired
if (wantExceptionLog) {
java.io.PrintStream log = System.err;
synchronized (log) {
log.println();
log.println("Exception dispatching call to " +
ref.getObjID() + " in thread \"" +
Thread.currentThread().getName() +
"\" at " + (new Date()) + ":");
e.printStackTrace(log);
}
}
}
/**
* Returns the class of the ref type to be serialized.
*/
public String getRefClass(ObjectOutput out) {
return "UnicastServerRef";
}
/**
* Return the client remote reference for this remoteRef.
* In the case of a client RemoteRef "this" is the answer.
* For a server remote reference, a client side one will have to
* found or created.
*/
protected RemoteRef getClientRef() {
return new UnicastRef(ref);
}
/**
* Write out external representation for remote ref.
*/
public void writeExternal(ObjectOutput out) throws IOException {
}
/**
* Read in external representation for remote ref.
* @exception ClassNotFoundException If the class for an object
* being restored cannot be found.
*/
public void readExternal(ObjectInput in)
throws IOException, ClassNotFoundException
{
// object is re-exported elsewhere (e.g., by UnicastRemoteObject)
ref = null;
skel = null;
}
/**
* A weak hash map, mapping classes to hash maps that map method
* hashes to method objects.
**/
private static class HashToMethod_Maps
extends WeakClassHashMap<Map<Long,Method>>
{
HashToMethod_Maps() {}
protected Map<Long,Method> computeValue(Class<?> remoteClass) {
Map<Long,Method> map = new HashMap<Long,Method>();
for (Class<?> cl = remoteClass;
cl != null;
cl = cl.getSuperclass())
{
for (Class<?> intf : cl.getInterfaces()) {
if (Remote.class.isAssignableFrom(intf)) {
for (Method method : intf.getMethods()) {
final Method m = method;
/*
* Set this Method object to override language
* access checks so that the dispatcher can invoke
* methods from non-public remote interfaces.
*/
AccessController.doPrivileged(
new PrivilegedAction<Void>() {
public Void run() {
m.setAccessible(true);
return null;
}
});
map.put(Util.computeMethodHash(m), m);
}
}
}
}
return map;
}
}
}