/*

 * Copyright (c) 2002, 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.  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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package javax.management.remote.rmi;

import com.sun.jmx.remote.internal.ClientCommunicatorAdmin;

import com.sun.jmx.remote.internal.ClientListenerInfo;

import com.sun.jmx.remote.internal.ClientNotifForwarder;

import com.sun.jmx.remote.internal.rmi.ProxyRef;

import com.sun.jmx.remote.util.ClassLogger;

import com.sun.jmx.remote.util.EnvHelp;

import java.io.ByteArrayInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.InvalidObjectException;

import java.io.ObjectInputStream;

import java.io.ObjectStreamClass;

import java.io.Serializable;

import java.lang.ref.WeakReference;

import java.lang.reflect.Constructor;

import java.lang.reflect.InvocationHandler;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Module;

import java.lang.reflect.Proxy;

import java.net.MalformedURLException;

import java.rmi.MarshalledObject;

import java.rmi.NoSuchObjectException;

import java.rmi.Remote;

import java.rmi.ServerException;

import java.rmi.UnmarshalException;

import java.rmi.server.RMIClientSocketFactory;

import java.rmi.server.RemoteObject;

import java.rmi.server.RemoteObjectInvocationHandler;

import java.rmi.server.RemoteRef;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.security.PrivilegedExceptionAction;

import java.security.ProtectionDomain;

import java.util.Arrays;

import java.util.Collections;

import java.util.HashMap;

import java.util.Hashtable;

import java.util.Map;

import java.util.Objects;

import java.util.Set;

import java.util.WeakHashMap;

import java.util.stream.Collectors;

import javax.management.Attribute;

import javax.management.AttributeList;

import javax.management.AttributeNotFoundException;

import javax.management.InstanceAlreadyExistsException;

import javax.management.InstanceNotFoundException;

import javax.management.IntrospectionException;

import javax.management.InvalidAttributeValueException;

import javax.management.ListenerNotFoundException;

import javax.management.MBeanException;

import javax.management.MBeanInfo;

import javax.management.MBeanRegistrationException;

import javax.management.MBeanServerConnection;

import javax.management.MBeanServerDelegate;

import javax.management.MBeanServerNotification;

import javax.management.NotCompliantMBeanException;

import javax.management.Notification;

import javax.management.NotificationBroadcasterSupport;

import javax.management.NotificationFilter;

import javax.management.NotificationFilterSupport;

import javax.management.NotificationListener;

import javax.management.ObjectInstance;

import javax.management.ObjectName;

import javax.management.QueryExp;

import javax.management.ReflectionException;

import javax.management.remote.JMXConnectionNotification;

import javax.management.remote.JMXConnector;

import javax.management.remote.JMXConnectorFactory;

import javax.management.remote.JMXServiceURL;

import javax.management.remote.NotificationResult;

import javax.management.remote.JMXAddressable;

import javax.naming.InitialContext;

import javax.naming.NamingException;

import javax.rmi.ssl.SslRMIClientSocketFactory;

import javax.security.auth.Subject;

import jdk.internal.module.Modules;

import sun.reflect.misc.ReflectUtil;

import sun.rmi.server.UnicastRef2;

import sun.rmi.transport.LiveRef;

import java.io.NotSerializableException;

/**

 * <p>A connection to a remote RMI connector.  Usually, such

 * connections are made using {@link

 * javax.management.remote.JMXConnectorFactory JMXConnectorFactory}.

 * However, specialized applications can use this class directly, for

 * example with an {@link RMIServer} stub obtained without going

 * through JNDI.</p>

 *

 * @since 1.5

 */

public class RMIConnector implements JMXConnector, Serializable, JMXAddressable {

    private static final ClassLogger logger =

            new ClassLogger("javax.management.remote.rmi", "RMIConnector");

    private static final long serialVersionUID = 817323035842634473L;

    static final class Util {

        private Util() {}

        /* This method can be used by code that is deliberately violating the

         * allowed checked casts.  Rather than marking the whole method containing

         * the code with @SuppressWarnings, you can use a call to this method for

         * the exact place where you need to escape the constraints.  Typically

         * you will "import static" this method and then write either

         *    X x = cast(y);

         * or, if that doesn't work (e.g. X is a type variable)

         *    Util.<X>cast(y);

         */

        @SuppressWarnings("unchecked")

        public static <T> T cast(Object x) {

            return (T) x;

        }

    }

    private RMIConnector(RMIServer rmiServer, JMXServiceURL address,

            Map<String, ?> environment) {

        if (rmiServer == null && address == null) throw new

                IllegalArgumentException("rmiServer and jmxServiceURL both null");

        initTransients();

        this.rmiServer = rmiServer;

        this.jmxServiceURL = address;

        if (environment == null) {

            this.env = Collections.emptyMap();

        } else {

            EnvHelp.checkAttributes(environment);

            this.env = Collections.unmodifiableMap(environment);

        }

    }

    /**

     * <p>Constructs an {@code RMIConnector} that will connect

     * the RMI connector server with the given address.</p>

     *

     * <p>The address can refer directly to the connector server,

     * using the following syntax:</p>

     *

     * <pre>

     * service:jmx:rmi://<em>[host[:port]]</em>/stub/<em>encoded-stub</em>

     * </pre>

     *

     * <p>(Here, the square brackets {@code []} are not part of the

     * address but indicate that the host and port are optional.)</p>

     *

     * <p>The address can instead indicate where to find an RMI stub

     * through JNDI, using the following syntax:</p>

     *

     * <pre>

     * service:jmx:rmi://<em>[host[:port]]</em>/jndi/<em>jndi-name</em>

     * </pre>

     *

     * <p>An implementation may also recognize additional address

     * syntaxes, for example:</p>

     *

     * <pre>

     * service:jmx:iiop://<em>[host[:port]]</em>/stub/<em>encoded-stub</em>

     * </pre>

     *

     * @param url the address of the RMI connector server.

     *

     * @param environment additional attributes specifying how to make

     * the connection.  For JNDI-based addresses, these attributes can

     * usefully include JNDI attributes recognized by {@link

     * InitialContext#InitialContext(Hashtable) InitialContext}.  This

     * parameter can be null, which is equivalent to an empty Map.

     *

     * @exception IllegalArgumentException if {@code url}

     * is null.

     */

    public RMIConnector(JMXServiceURL url, Map<String,?> environment) {

        this(null, url, environment);

    }

    /**

     * <p>Constructs an {@code RMIConnector} using the given RMI stub.

     *

     * @param rmiServer an RMI stub representing the RMI connector server.

     * @param environment additional attributes specifying how to make

     * the connection.  This parameter can be null, which is

     * equivalent to an empty Map.

     *

     * @exception IllegalArgumentException if {@code rmiServer}

     * is null.

     */

    public RMIConnector(RMIServer rmiServer, Map<String,?> environment) {

        this(rmiServer, null, environment);

    }

    /**

     * <p>Returns a string representation of this object.  In general,

     * the {@code toString} method returns a string that

     * "textually represents" this object. The result should be a

     * concise but informative representation that is easy for a

     * person to read.</p>

     *

     * @return a String representation of this object.

     **/

    @Override

    public String toString() {

        final StringBuilder b = new StringBuilder(this.getClass().getName());

        b.append(":");

        if (rmiServer != null) {

            b.append(" rmiServer=").append(rmiServer.toString());

        }

        if (jmxServiceURL != null) {

            if (rmiServer!=null) b.append(",");

            b.append(" jmxServiceURL=").append(jmxServiceURL.toString());

        }

        return b.toString();

    }

    /**

     * <p>The address of this connector.</p>

     *

     * @return the address of this connector, or null if it

     * does not have one.

     *

     * @since 1.6

     */

    public JMXServiceURL getAddress() {

        return jmxServiceURL;

    }

    //--------------------------------------------------------------------

    // implements JMXConnector interface

    //--------------------------------------------------------------------

    /**

     * @throws IOException if the connection could not be made because of a

     *   communication problem

     */

    public void connect() throws IOException {

        connect(null);

    }

    /**

     * @throws IOException if the connection could not be made because of a

     *   communication problem

     */

    public synchronized void connect(Map<String,?> environment)

    throws IOException {

        final boolean tracing = logger.traceOn();

        String        idstr   = (tracing?"["+this.toString()+"]":null);

        if (terminated) {

            logger.trace("connect",idstr + " already closed.");

            throw new IOException("Connector closed");

        }

        if (connected) {

            logger.trace("connect",idstr + " already connected.");

            return;

        }

        try {

            if (tracing) logger.trace("connect",idstr + " connecting...");

            final Map<String, Object> usemap =

                    new HashMap<String, Object>((this.env==null) ?

                        Collections.<String, Object>emptyMap() : this.env);

            if (environment != null) {

                EnvHelp.checkAttributes(environment);

                usemap.putAll(environment);

            }

            // Get RMIServer stub from directory or URL encoding if needed.

            if (tracing) logger.trace("connect",idstr + " finding stub...");

            RMIServer stub = (rmiServer!=null)?rmiServer:

                findRMIServer(jmxServiceURL, usemap);

            // Check for secure RMIServer stub if the corresponding

            // client-side environment property is set to "true".

            //

            String stringBoolean =  (String) usemap.get("jmx.remote.x.check.stub");

            boolean checkStub = EnvHelp.computeBooleanFromString(stringBoolean);

            if (checkStub) checkStub(stub, rmiServerImplStubClass);

            if (tracing) logger.trace("connect",idstr + " connecting stub...");

            idstr = (tracing?"["+this.toString()+"]":null);

            // Calling newClient on the RMIServer stub.

            if (tracing)

                logger.trace("connect",idstr + " getting connection...");

            Object credentials = usemap.get(CREDENTIALS);

            try {

                connection = getConnection(stub, credentials, checkStub);

            } catch (java.rmi.RemoteException re) {

                throw re;

            }

            // Always use one of:

            //   ClassLoader provided in Map at connect time,

            //   or contextClassLoader at connect time.

            if (tracing)

                logger.trace("connect",idstr + " getting class loader...");

            defaultClassLoader = EnvHelp.resolveClientClassLoader(usemap);

            usemap.put(JMXConnectorFactory.DEFAULT_CLASS_LOADER,

                    defaultClassLoader);

            rmiNotifClient = new RMINotifClient(defaultClassLoader, usemap);

            env = usemap;

            final long checkPeriod = EnvHelp.getConnectionCheckPeriod(usemap);

            communicatorAdmin = new RMIClientCommunicatorAdmin(checkPeriod);

            connected = true;

            // The connectionId variable is used in doStart(), when

            // reconnecting, to identify the "old" connection.

            //

            connectionId = getConnectionId();

            Notification connectedNotif =

                    new JMXConnectionNotification(JMXConnectionNotification.OPENED,

                    this,

                    connectionId,

                    clientNotifSeqNo++,

                    "Successful connection",

                    null);

            sendNotification(connectedNotif);

            if (tracing) logger.trace("connect",idstr + " done...");

        } catch (IOException e) {

            if (tracing)

                logger.trace("connect",idstr + " failed to connect: " + e);

            throw e;

        } catch (RuntimeException e) {

            if (tracing)

                logger.trace("connect",idstr + " failed to connect: " + e);

            throw e;

        } catch (NamingException e) {

            final String msg = "Failed to retrieve RMIServer stub: " + e;

            if (tracing) logger.trace("connect",idstr + " " + msg);

            throw EnvHelp.initCause(new IOException(msg),e);

        }

    }

    public synchronized String getConnectionId() throws IOException {

        if (terminated || !connected) {

            if (logger.traceOn())

                logger.trace("getConnectionId","["+this.toString()+

                        "] not connected.");

            throw new IOException("Not connected");

        }

        // we do a remote call to have an IOException if the connection is broken.

        // see the bug 4939578

        return connection.getConnectionId();

    }

    public synchronized MBeanServerConnection getMBeanServerConnection()

    throws IOException {

        return getMBeanServerConnection(null);

    }

    public synchronized MBeanServerConnection

            getMBeanServerConnection(Subject delegationSubject)

            throws IOException {

        if (terminated) {

            if (logger.traceOn())

                logger.trace("getMBeanServerConnection","[" + this.toString() +

                        "] already closed.");

            throw new IOException("Connection closed");

        } else if (!connected) {

            if (logger.traceOn())

                logger.trace("getMBeanServerConnection","[" + this.toString() +

                        "] is not connected.");

            throw new IOException("Not connected");

        }

        return getConnectionWithSubject(delegationSubject);

    }

    public void

            addConnectionNotificationListener(NotificationListener listener,

            NotificationFilter filter,

            Object handback) {

        if (listener == null)

            throw new NullPointerException("listener");

        connectionBroadcaster.addNotificationListener(listener, filter,

                handback);

    }

    public void

            removeConnectionNotificationListener(NotificationListener listener)

            throws ListenerNotFoundException {

        if (listener == null)

            throw new NullPointerException("listener");

        connectionBroadcaster.removeNotificationListener(listener);

    }

    public void

            removeConnectionNotificationListener(NotificationListener listener,

            NotificationFilter filter,

            Object handback)

            throws ListenerNotFoundException {

        if (listener == null)

            throw new NullPointerException("listener");

        connectionBroadcaster.removeNotificationListener(listener, filter,

                handback);

    }

    private void sendNotification(Notification n) {

        connectionBroadcaster.sendNotification(n);

    }

    public synchronized void close() throws IOException {

        close(false);

    }

    // allows to do close after setting the flag "terminated" to true.

    // It is necessary to avoid a deadlock, see 6296324

    private synchronized void close(boolean intern) throws IOException {

        final boolean tracing = logger.traceOn();

        final boolean debug   = logger.debugOn();

        final String  idstr   = (tracing?"["+this.toString()+"]":null);

        if (!intern) {

            // Return if already cleanly closed.

            //

            if (terminated) {

                if (closeException == null) {

                    if (tracing) logger.trace("close",idstr + " already closed.");

                    return;

                }

            } else {

                terminated = true;

            }

        }

        if (closeException != null && tracing) {

            // Already closed, but not cleanly. Attempt again.

            //

            if (tracing) {

                logger.trace("close",idstr + " had failed: " + closeException);

                logger.trace("close",idstr + " attempting to close again.");

            }

        }

        String savedConnectionId = null;

        if (connected) {

            savedConnectionId = connectionId;

        }

        closeException = null;

        if (tracing) logger.trace("close",idstr + " closing.");

        if (communicatorAdmin != null) {

            communicatorAdmin.terminate();

        }

        if (rmiNotifClient != null) {

            try {

                rmiNotifClient.terminate();

                if (tracing) logger.trace("close",idstr +

                        " RMI Notification client terminated.");

            } catch (RuntimeException x) {

                closeException = x;

                if (tracing) logger.trace("close",idstr +

                        " Failed to terminate RMI Notification client: " + x);

                if (debug) logger.debug("close",x);

            }

        }

        if (connection != null) {

            try {

                connection.close();

                if (tracing) logger.trace("close",idstr + " closed.");

            } catch (NoSuchObjectException nse) {

                // OK, the server maybe closed itself.

            } catch (IOException e) {

                closeException = e;

                if (tracing) logger.trace("close",idstr +

                        " Failed to close RMIServer: " + e);

                if (debug) logger.debug("close",e);

            }

        }

        // Clean up MBeanServerConnection table