Update of /cvsroot/mx4j/mx4j/src/core/mx4j/remote/rmi
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv27925/src/core/mx4j/remote/rmi
Modified Files:
RMIMarshaller.java
Added Files:
Marshaller.java
Log Message:
Fixed RMI Marshalling bug
--- NEW FILE: Marshaller.java ---
/*
* Copyright (C) MX4J.
* All rights reserved.
*
* This software is distributed under the terms of the MX4J License version 1.0.
* See the terms of the MX4J License in the documentation provided with this software.
*/
package mx4j.remote.rmi;
import java.io.IOException;
import java.rmi.MarshalledObject;
/**
* IMPORTANT: see {@link RMIMarshaller}
* @author <a href="mailto:[email protected]">Simone Bordet</a>
* @version $Revision: 1.1 $
*/
public class Marshaller
{
public static Object unmarshal(MarshalledObject obj) throws IOException, ClassNotFoundException
{
return obj.get();
}
}
Index: RMIMarshaller.java
===================================================================
RCS file: /cvsroot/mx4j/mx4j/src/core/mx4j/remote/rmi/RMIMarshaller.java,v
retrieving revision 1.7
retrieving revision 1.8
diff -C2 -d -r1.7 -r1.8
*** RMIMarshaller.java 1 Mar 2004 18:19:55 -0000 1.7
--- RMIMarshaller.java 10 Mar 2004 18:33:35 -0000 1.8
***************
*** 9,25 ****
package mx4j.remote.rmi;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
- import java.net.URLClassLoader;
import java.rmi.MarshalledObject;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
/**
! * Marshaller/Unmarshaller for RMI's MarshalledObjects.
*
* @author <a href="mailto:[email protected]">Simone Bordet</a>
--- 9,61 ----
package mx4j.remote.rmi;
+ import java.io.BufferedInputStream;
+ import java.io.BufferedOutputStream;
+ import java.io.ByteArrayOutputStream;
import java.io.IOException;
+ import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
import java.rmi.MarshalledObject;
import java.security.AccessController;
import java.security.PrivilegedAction;
+ import java.security.SecureClassLoader;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
/**
! * Marshaller/Unmarshaller for RMI's MarshalledObjects. <br />
! *
! * This class implements the JMX Remote Specification, chapter 2. <br />
! * <strong>
! * Don't touch unless discussed on [email protected], and unless
! * you know what you're doing (included who wrote this javadoc).
! * </strong>
! * <br />
! * IMPLEMENTATION NOTES: <br />
! * MarshalledObject.get() loads the object it contains by using the first user-defined classloader it can find
! * in the stack frames of the call. <br />
! * If the class cannot be found with that loader, then the RMI semantic is tried: first the thread context
! * classloader, then dynamic code download (if there is a security manager). <br />
! * We need that MarshalledObject.get() unmarshals using the context classloader and not the first user-defined
! * classloader, since this way we can implement correctly the JMX specification (see
! * {@link #unmarshal(MarshalledObject, ClassLoader, ClassLoader)}). <br />
! * Here we load the {@link Marshaller} class using {@link MarshallerClassLoader} that can only load the
! * {@link Marshaller} class.
! * It is important that {@link MarshallerClassLoader} cannot load from the classpath (the system classloader)
! * since that would break the JMX Remote Specification compliance. <br />
! * This URLClassLoader then becomes the first user-defined classloader in the stack frames, but it will fail
! * to load anything else, thus allowing MarshalledObject.get() to use the thread context classloader.
! * The stack trace will be something like:
! * <pre>
! * {@link Marshaller#unmarshal} [MarshallerClassLoader]
! * ... reflection classes ... [Boot ClassLoader]
! * {@link RMIMarshaller#unmarshal(MarshalledObject)} [System ClassLoader (normally)]
! * </pre>
! * <br />
! * Note that the classloader that loaded this class may be something totally different from URLClassLoader:
! * this is the case for the <a href="http://www.osgi.org">OSGi</a>. <br />
! * We just rely on the {@link ClassLoader#getResourceAsStream(java.lang.String)} semantic to load the
! * {@link Marshaller} class' bytes.
*
* @author <a href="mailto:[email protected]">Simone Bordet</a>
***************
*** 28,63 ****
class RMIMarshaller
{
! private static Method unmarshal;
! /**
! * MarshalledObject.get() loads the object it contains by using the first user-defined classloader it can find
! * in the stack frames of the call.
! * In a normal usage of JSR 160, this classloader is the one that loaded this class, most probably
! * the system classloader.
! * If the class cannot be found with that loader, then the RMI semantic is tried: first the thread context
! * classloader, then dynamic code download (if there is a security manager).
! * Here we load the Marshaller class using an URLClassLoader that is only able to load classes from the URL
! * where it loaded this class, thus it cannot see other classes in the system classloader.
! * This URLClassLoader then becomes the first user-defined classloader in the stack frames, but it will fail
! * to load anything else, thus allowing MarshalledObject.get() to use the thread context classloader.
! */
! static
{
try
{
! AccessController.doPrivileged(new PrivilegedExceptionAction()
! {
! public Object run() throws Exception
! {
! URL url = RMIMarshaller.class.getProtectionDomain().getCodeSource().getLocation();
! // TODO: is it enough to use the parent, or maybe better use null as parent classloader ?
! URLClassLoader loader = new URLClassLoader(new URL[] {url}, RMIMarshaller.class.getClassLoader().getParent());
! Class marshaller = loader.loadClass(Marshaller.class.getName());
! unmarshal = marshaller.getMethod("unmarshal", new Class[] {MarshalledObject.class});
! return null;
! }
! });
}
! catch (PrivilegedActionException x)
{
throw new Error(x.toString());
--- 64,104 ----
class RMIMarshaller
{
! private static final Method unmarshal = getUnmarshalMethod();
! private static Method getUnmarshalMethod()
{
+ String marshallerName = Marshaller.class.getName();
+ InputStream stream = Marshaller.class.getResourceAsStream(marshallerName.substring(marshallerName.lastIndexOf('.') + 1) + ".class");
+ if (stream == null) throw new Error("Could not load implementation class " + marshallerName);
+ BufferedInputStream bis = new BufferedInputStream(stream);
+ ByteArrayOutputStream baos = new ByteArrayOutputStream();
+ BufferedOutputStream bos = new BufferedOutputStream(baos);
try
{
! byte[] buffer = new byte[256];
! int read = -1;
! while ((read = bis.read(buffer)) >= 0) bos.write(buffer, 0, read);
! bis.close();
! bos.close();
}
! catch (IOException x)
! {
! throw new Error(x.toString());
! }
!
! byte[] classBytes = baos.toByteArray();
!
! MarshallerClassLoader loader = new MarshallerClassLoader(classBytes);
!
! try
! {
! Class cls = loader.loadClass(marshallerName);
! return cls.getMethod("unmarshal", new Class[]{MarshalledObject.class});
! }
! catch (ClassNotFoundException x)
! {
! throw new Error(x.toString());
! }
! catch (NoSuchMethodException x)
{
throw new Error(x.toString());
***************
*** 87,91 ****
public Object run()
{
! return new MarshallerClassLoader(mbeanLoader, defaultLoader);
}
});
--- 128,132 ----
public Object run()
{
! return new ExtendedClassLoader(mbeanLoader, defaultLoader);
}
});
***************
*** 149,165 ****
}
! public static class Marshaller
{
! public static Object unmarshal(MarshalledObject obj) throws IOException, ClassNotFoundException
{
! return obj.get();
}
}
! private static class MarshallerClassLoader extends ClassLoader
{
private final ClassLoader defaultLoader;
! private MarshallerClassLoader(ClassLoader mbeanLoader, ClassLoader defaultLoader)
{
super(mbeanLoader);
--- 190,249 ----
}
! private static class MarshallerClassLoader extends SecureClassLoader
{
! private byte[] bytes;
!
! private MarshallerClassLoader(byte[] classBytes)
{
! super(null);
! this.bytes = classBytes;
! }
!
! /**
! * This method is overridden to load only classes from the java.* packages and the
! * {@link Marshaller} class ONLY.
! * Classes from java.* packages (like java.lang.Object and java.rmi.MarshalledObject) are
! * referenced by {@link Marshaller} itself.
! * We don't load classes from javax.management.* packages, since we assume the context classloader
! * can load those classes by itself or by one of its ancestor classloaders.
! */
! public Class loadClass(final String name) throws ClassNotFoundException
! {
! if (name.startsWith("java.")) return super.loadClass(name);
! if (!name.startsWith(Marshaller.class.getName())) throw new ClassNotFoundException(name);
!
! try
! {
! return (Class)AccessController.doPrivileged(new PrivilegedExceptionAction()
! {
! public Object run() throws ClassNotFoundException
! {
! try
! {
! return defineClass(name, bytes, 0, bytes.length, MarshallerClassLoader.this.getClass().getProtectionDomain());
! }
! catch (ClassFormatError x)
! {
! throw new ClassNotFoundException("Class Format Error", x);
! }
! }
! }, null);
! }
! catch (PrivilegedActionException x)
! {
! throw (ClassNotFoundException)x.getException();
! }
}
}
! /**
! * This is an implementation of the extended classloader as defined by the
! * JMX Remote Specification, chapter 2.
! */
! private static class ExtendedClassLoader extends SecureClassLoader
{
private final ClassLoader defaultLoader;
! private ExtendedClassLoader(ClassLoader mbeanLoader, ClassLoader defaultLoader)
{
super(mbeanLoader);
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