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 * 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
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package javax.management.remote.rmi;

import java.io.IOException;
import java.rmi.NoSuchObjectException;
import java.rmi.Remote;
import java.rmi.RemoteException;
import java.rmi.server.RMIClientSocketFactory;
import java.rmi.server.RMIServerSocketFactory;
import java.rmi.server.UnicastRemoteObject;
import java.rmi.server.RemoteObject;
import java.util.Map;
import java.util.Collections;
import javax.security.auth.Subject;

import com.sun.jmx.remote.internal.RMIExporter;
import com.sun.jmx.remote.util.EnvHelp;
import java.io.ObjectStreamClass;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import sun.reflect.misc.ReflectUtil;
import sun.rmi.server.DeserializationChecker;
import sun.rmi.server.UnicastServerRef;
import sun.rmi.server.UnicastServerRef2;

/**
 * <p>An {@link RMIServer} object that is exported through JRMP and that
 * creates client connections as RMI objects exported through JRMP.
 * User code does not usually reference this class directly.</p>
 *
 * @see RMIServerImpl
 *
 * @since 1.5
 */
public class RMIJRMPServerImpl extends RMIServerImpl {

    private final ExportedWrapper exportedWrapper;

    /**
     * <p>Creates a new {@link RMIServer} object that will be exported
     * on the given port using the given socket factories.</p>
     *
     * @param port the port on which this object and the {@link
     * RMIConnectionImpl} objects it creates will be exported.  Can be
     * zero, to indicate any available port.
     *
     * @param csf the client socket factory for the created RMI
     * objects.  Can be null.
     *
     * @param ssf the server socket factory for the created RMI
     * objects.  Can be null.
     *
     * @param env the environment map.  Can be null.
     *
     * @exception IOException if the {@link RMIServer} object
     * cannot be created.
     *
     * @exception IllegalArgumentException if <code>port</code> is
     * negative.
     */
    public RMIJRMPServerImpl(int port,
                             RMIClientSocketFactory csf,
                             RMIServerSocketFactory ssf,
                             Map<String,?> env)
            throws IOException {

        super(env);

        if (port < 0)
            throw new IllegalArgumentException("Negative port: " + port);

        this.port = port;
        this.csf = csf;
        this.ssf = ssf;
        this.env = (env == null) ? Collections.<String, Object>emptyMap() : env;

        String[] credentialsTypes
                = (String[]) this.env.get(EnvHelp.CREDENTIAL_TYPES);
        List<String> types = null;
        if (credentialsTypes != null) {
            types = new ArrayList<>();
            for (String type : credentialsTypes) {
                if (type == null) {
                    throw new IllegalArgumentException("A credential type is null.");
                }
                ReflectUtil.checkPackageAccess(type);
                types.add(type);
            }
        }
        exportedWrapper = types != null ?
                new ExportedWrapper(this, types) :
                null;
    }

    protected void export() throws IOException {
        if (exportedWrapper != null) {
            export(exportedWrapper);
        } else {
            export(this);
        }
    }

    private void export(Remote obj) throws RemoteException {
        final RMIExporter exporter =
            (RMIExporter) env.get(RMIExporter.EXPORTER_ATTRIBUTE);
        final boolean daemon = EnvHelp.isServerDaemon(env);

        if (daemon && exporter != null) {
            throw new IllegalArgumentException("If "+EnvHelp.JMX_SERVER_DAEMON+
                    " is specified as true, "+RMIExporter.EXPORTER_ATTRIBUTE+
                    " cannot be used to specify an exporter!");
        }

        if (daemon) {
            if (csf == null && ssf == null) {
                new UnicastServerRef(port).exportObject(obj, null, true);
            } else {
                new UnicastServerRef2(port, csf, ssf).exportObject(obj, null, true);
            }
        } else if (exporter != null) {
            exporter.exportObject(obj, port, csf, ssf);
        } else {
            UnicastRemoteObject.exportObject(obj, port, csf, ssf);
        }
    }

    private void unexport(Remote obj, boolean force)
            throws NoSuchObjectException {
        RMIExporter exporter =
            (RMIExporter) env.get(RMIExporter.EXPORTER_ATTRIBUTE);
        if (exporter == null)
            UnicastRemoteObject.unexportObject(obj, force);
        else
            exporter.unexportObject(obj, force);
    }

    protected String getProtocol() {
        return "rmi";
    }

    /**
     * <p>Returns a serializable stub for this {@link RMIServer} object.</p>
     *
     * @return a serializable stub.
     *
     * @exception IOException if the stub cannot be obtained - e.g the
     *            RMIJRMPServerImpl has not been exported yet.
     */
    public Remote toStub() throws IOException {
        if (exportedWrapper != null) {
            return RemoteObject.toStub(exportedWrapper);
        } else {
            return RemoteObject.toStub(this);
        }
    }

    /**
     * <p>Creates a new client connection as an RMI object exported
     * through JRMP. The port and socket factories for the new
     * {@link RMIConnection} object are the ones supplied
     * to the <code>RMIJRMPServerImpl</code> constructor.</p>
     *
     * @param connectionId the ID of the new connection. Every
     * connection opened by this connector server will have a
     * different id.  The behavior is unspecified if this parameter is
     * null.
     *
     * @param subject the authenticated subject.  Can be null.
     *
     * @return the newly-created <code>RMIConnection</code>.
     *
     * @exception IOException if the new {@link RMIConnection}
     * object cannot be created or exported.
     */
    protected RMIConnection makeClient(String connectionId, Subject subject)
            throws IOException {

        if (connectionId == null)
            throw new NullPointerException("Null connectionId");

        RMIConnection client =
            new RMIConnectionImpl(this, connectionId, getDefaultClassLoader(),
                                  subject, env);
        export(client);
        return client;
    }

    protected void closeClient(RMIConnection client) throws IOException {
        unexport(client, true);
    }

    /**
     * <p>Called by {@link #close()} to close the connector server by
     * unexporting this object.  After returning from this method, the
     * connector server must not accept any new connections.</p>
     *
     * @exception IOException if the attempt to close the connector
     * server failed.
     */
    protected void closeServer() throws IOException {
        if (exportedWrapper != null) {
            unexport(exportedWrapper, true);
        } else {
            unexport(this, true);
        }
    }

    private final int port;
    private final RMIClientSocketFactory csf;
    private final RMIServerSocketFactory ssf;
    private final Map<String, ?> env;

    private static class ExportedWrapper implements RMIServer, DeserializationChecker {
        private final RMIServer impl;
        private final List<String> allowedTypes;
        private ExportedWrapper(RMIServer impl, List<String> credentialsTypes) {
            this.impl = impl;
            allowedTypes = credentialsTypes;
        }

        @Override
        public String getVersion() throws RemoteException {
            return impl.getVersion();
        }

        @Override
        public RMIConnection newClient(Object credentials) throws IOException {
            return impl.newClient(credentials);
        }

        @Override
        public void check(Method method, ObjectStreamClass descriptor,
                int paramIndex, int callID) {

            String type = descriptor.getName();
            if (!allowedTypes.contains(type)) {
                throw new ClassCastException("Unsupported type: " + type);
            }
        }

        @Override
        public void checkProxyClass(Method method, String[] ifaces,
                int paramIndex, int callID) {
            if (ifaces != null && ifaces.length > 0) {
                for (String iface : ifaces) {
                    if (!allowedTypes.contains(iface)) {
                        throw new ClassCastException("Unsupported type: " + iface);
                    }
                }
            }
        }
    }
}