/*

 * Copyright (c) 1997, 2014, 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 sun.rmi.server;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.ObjectInput;

import java.io.ObjectInputStream;

import java.io.OutputStream;

import java.io.PrintStream;

import java.io.PrintWriter;

import java.io.Serializable;

import java.lang.Process;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.net.InetAddress;

import java.net.ServerSocket;

import java.net.Socket;

import java.net.SocketAddress;

import java.net.SocketException;

import java.nio.file.Files;

import java.nio.channels.Channel;

import java.nio.channels.ServerSocketChannel;

import java.rmi.AccessException;

import java.rmi.AlreadyBoundException;

import java.rmi.ConnectException;

import java.rmi.ConnectIOException;

import java.rmi.MarshalledObject;

import java.rmi.NoSuchObjectException;

import java.rmi.NotBoundException;

import java.rmi.Remote;

import java.rmi.RemoteException;

import java.rmi.activation.ActivationDesc;

import java.rmi.activation.ActivationException;

import java.rmi.activation.ActivationGroupDesc;

import java.rmi.activation.ActivationGroup;

import java.rmi.activation.ActivationGroupID;

import java.rmi.activation.ActivationID;

import java.rmi.activation.ActivationInstantiator;

import java.rmi.activation.ActivationMonitor;

import java.rmi.activation.ActivationSystem;

import java.rmi.activation.Activator;

import java.rmi.activation.UnknownGroupException;

import java.rmi.activation.UnknownObjectException;

import java.rmi.registry.Registry;

import java.rmi.server.ObjID;

import java.rmi.server.RMIClassLoader;

import java.rmi.server.RMIClientSocketFactory;

import java.rmi.server.RMIServerSocketFactory;

import java.rmi.server.RemoteObject;

import java.rmi.server.RemoteServer;

import java.rmi.server.UnicastRemoteObject;

import java.security.AccessControlException;

import java.security.AccessController;

import java.security.AllPermission;

import java.security.CodeSource;

import java.security.Permission;

import java.security.PermissionCollection;

import java.security.Permissions;

import java.security.Policy;

import java.security.PrivilegedAction;

import java.security.PrivilegedExceptionAction;

import java.security.cert.Certificate;

import java.text.MessageFormat;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Date;

import java.util.Enumeration;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import java.util.MissingResourceException;

import java.util.Properties;

import java.util.ResourceBundle;

import java.util.Set;

import java.util.concurrent.ConcurrentHashMap;

import sun.rmi.log.LogHandler;

import sun.rmi.log.ReliableLog;

import sun.rmi.registry.RegistryImpl;

import sun.rmi.runtime.NewThreadAction;

import sun.rmi.transport.LiveRef;

import sun.security.provider.PolicyFile;

import com.sun.rmi.rmid.ExecPermission;

import com.sun.rmi.rmid.ExecOptionPermission;

/**

 * The Activator facilitates remote object activation. A "faulting"

 * remote reference calls the activator's <code>activate</code> method

 * to obtain a "live" reference to a activatable remote object. Upon

 * receiving a request for activation, the activator looks up the

 * activation descriptor for the activation identifier, id, determines

 * the group in which the object should be activated and invokes the

 * activate method on the object's activation group (described by the

 * remote interface <code>ActivationInstantiator</code>). The

 * activator initiates the execution of activation groups as

 * necessary. For example, if an activation group for a specific group

 * identifier is not already executing, the activator will spawn a

 * child process for the activation group. <p>

 *

 * The activator is responsible for monitoring and detecting when

 * activation groups fail so that it can remove stale remote references

 * from its internal tables. <p>

 *

 * @author      Ann Wollrath

 * @since       1.2

 */

public class Activation implements Serializable {

    /** indicate compatibility with JDK 1.2 version of class */

    private static final long serialVersionUID = 2921265612698155191L;

    private static final byte MAJOR_VERSION = 1;

    private static final byte MINOR_VERSION = 0;

    /** exec policy object */

    private static Object execPolicy;

    private static Method execPolicyMethod;

    private static boolean debugExec;

    /** maps activation id to its respective group id */

    private Map<ActivationID,ActivationGroupID> idTable =

        new ConcurrentHashMap<>();

    /** maps group id to its GroupEntry groups */

    private Map<ActivationGroupID,GroupEntry> groupTable =

        new ConcurrentHashMap<>();

    private byte majorVersion = MAJOR_VERSION;

    private byte minorVersion = MINOR_VERSION;

    /** number of simultaneous group exec's */

    private transient int groupSemaphore;

    /** counter for numbering groups */

    private transient int groupCounter;

    /** reliable log to hold descriptor table */

    private transient ReliableLog log;

    /** number of updates since last snapshot */

    private transient int numUpdates;

    /** the java command */

    // accessed by GroupEntry

    private transient String[] command;

    /** timeout on wait for child process to be created or destroyed */

    private static final long groupTimeout =

        getInt("sun.rmi.activation.groupTimeout", 60000);

    /** take snapshot after this many updates */

    private static final int snapshotInterval =

        getInt("sun.rmi.activation.snapshotInterval", 200);

    /** timeout on wait for child process to be created */

    private static final long execTimeout =

        getInt("sun.rmi.activation.execTimeout", 30000);

    private static final Object initLock = new Object();

    private static boolean initDone = false;

    // this should be a *private* method since it is privileged

    private static int getInt(String name, int def) {

        return AccessController.doPrivileged(

                (PrivilegedAction<Integer>) () -> Integer.getInteger(name, def));

    }

    private transient Activator activator;

    private transient Activator activatorStub;

    private transient ActivationSystem system;

    private transient ActivationSystem systemStub;

    private transient ActivationMonitor monitor;

    private transient Registry registry;

    private transient volatile boolean shuttingDown = false;

    private transient volatile Object startupLock;

    private transient Thread shutdownHook;

    private static ResourceBundle resources = null;

    /**

     * Create an uninitialized instance of Activation that can be

     * populated with log data.  This is only called when the initial

     * snapshot is taken during the first incarnation of rmid.

     */

    private Activation() {}

    /**

     * Recover activation state from the reliable log and initialize

     * activation services.

     */

    private static void startActivation(int port,

                                        RMIServerSocketFactory ssf,

                                        String logName,

                                        String[] childArgs)

        throws Exception

    {

        ReliableLog log = new ReliableLog(logName, new ActLogHandler());

        Activation state = (Activation) log.recover();

        state.init(port, ssf, log, childArgs);

    }

    /**

     * Initialize the Activation instantiation; start activation

     * services.

     */

    private void init(int port,

                      RMIServerSocketFactory ssf,

                      ReliableLog log,

                      String[] childArgs)

        throws Exception

    {

        // initialize

        this.log = log;

        numUpdates = 0;

        shutdownHook =  new ShutdownHook();

        groupSemaphore = getInt("sun.rmi.activation.groupThrottle", 3);

        groupCounter = 0;

        Runtime.getRuntime().addShutdownHook(shutdownHook);

        // Use array size of 0, since the value from calling size()

        // may be out of date by the time toArray() is called.

        ActivationGroupID[] gids =

            groupTable.keySet().toArray(new ActivationGroupID[0]);

        synchronized (startupLock = new Object()) {

            // all the remote methods briefly synchronize on startupLock

            // (via checkShutdown) to make sure they don't happen in the

            // middle of this block.  This block must not cause any such

            // incoming remote calls to happen, or deadlock would result!

            activator = new ActivatorImpl(port, ssf);

            activatorStub = (Activator) RemoteObject.toStub(activator);

            system = new ActivationSystemImpl(port, ssf);

            systemStub = (ActivationSystem) RemoteObject.toStub(system);

            monitor = new ActivationMonitorImpl(port, ssf);

            initCommand(childArgs);

            registry = new SystemRegistryImpl(port, null, ssf, systemStub);

            if (ssf != null) {

                synchronized (initLock) {

                    initDone = true;

                    initLock.notifyAll();

                }

            }

        }

        startupLock = null;

        // restart services

        for (int i = gids.length; --i >= 0; ) {

            try {

                getGroupEntry(gids[i]).restartServices();

            } catch (UnknownGroupException e) {

                System.err.println(

                    getTextResource("rmid.restart.group.warning"));

                e.printStackTrace();

            }

        }

    }

    /**

     * Previous versions used HashMap instead of ConcurrentHashMap.

     * Replace any HashMaps found during deserialization with

     * ConcurrentHashMaps.

     */

    private void readObject(ObjectInputStream ois)

        throws IOException, ClassNotFoundException

    {

        ois.defaultReadObject();

        if (! (groupTable instanceof ConcurrentHashMap)) {

            groupTable = new ConcurrentHashMap<>(groupTable);

        }

        if (! (idTable instanceof ConcurrentHashMap)) {

            idTable = new ConcurrentHashMap<>(idTable);

        }

    }

    private static class SystemRegistryImpl extends RegistryImpl {

        private static final String NAME = ActivationSystem.class.getName();

        private static final long serialVersionUID = 4877330021609408794L;

        private ActivationSystem systemStub = null;

        SystemRegistryImpl(int port,

                           RMIClientSocketFactory csf,

                           RMIServerSocketFactory ssf,

                           ActivationSystem systemStub)

            throws RemoteException

        {

            super(port, csf, ssf);

            assert systemStub != null;

            synchronized (this) {

                this.systemStub = systemStub;

                notifyAll();

            }

        }

        /**

         * Waits for systemStub to be initialized and returns its

         * initialized value. Any remote call that uses systemStub must

         * call this method to get it instead of using direct field

         * access. This is necessary because the super() call in the

         * constructor exports this object before systemStub is initialized

         * (see JDK-8023541), allowing remote calls to come in during this

         * time. We can't use checkShutdown() like other nested classes

         * because this is a static class.

         */

        private synchronized ActivationSystem getSystemStub() {

            boolean interrupted = false;

            while (systemStub == null) {

                try {

                    wait();

                } catch (InterruptedException ie) {

                    interrupted = true;

                }

            }

            if (interrupted) {

                Thread.currentThread().interrupt();

            }

            return systemStub;

        }

        /**

         * Returns the activation system stub if the specified name

         * matches the activation system's class name, otherwise

         * returns the result of invoking super.lookup with the specified

         * name.

         */

        public Remote lookup(String name)

            throws RemoteException, NotBoundException

        {

            if (name.equals(NAME)) {

                return getSystemStub();

            } else {

                return super.lookup(name);

            }

        }

        public String[] list() throws RemoteException {

            String[] list1 = super.list();

            int length = list1.length;

            String[] list2 = new String[length + 1];

            if (length > 0) {

                System.arraycopy(list1, 0, list2, 0, length);

            }

            list2[length] = NAME;

            return list2;

        }

        public void bind(String name, Remote obj)

            throws RemoteException, AlreadyBoundException, AccessException

        {

            if (name.equals(NAME)) {

                throw new AccessException(

                    "binding ActivationSystem is disallowed");

            } else {

                RegistryImpl.checkAccess("ActivationSystem.bind");

                super.bind(name, obj);

            }

        }

        public void unbind(String name)

            throws RemoteException, NotBoundException, AccessException

        {

            if (name.equals(NAME)) {

                throw new AccessException(

                    "unbinding ActivationSystem is disallowed");

            } else {

                RegistryImpl.checkAccess("ActivationSystem.unbind");

                super.unbind(name);

            }

        }

        public void rebind(String name, Remote obj)

            throws RemoteException, AccessException

        {

            if (name.equals(NAME)) {

                throw new AccessException(

                    "binding ActivationSystem is disallowed");

            } else {

                RegistryImpl.checkAccess("ActivationSystem.rebind");

                super.rebind(name, obj);

            }

        }

    }

    class ActivatorImpl extends RemoteServer implements Activator {

        // Because ActivatorImpl has a fixed ObjID, it can be

        // called by clients holding stale remote references.  Each of

        // its remote methods, then, must check startupLock (calling

        // checkShutdown() is easiest).

        private static final long serialVersionUID = -3654244726254566136L;

        /**

         * Construct a new Activator on a specified port.

         */

        ActivatorImpl(int port, RMIServerSocketFactory ssf)

            throws RemoteException

        {

            /* Server ref must be created and assigned before remote object

             * 'this' can be exported.

             */

            LiveRef lref =

                new LiveRef(new ObjID(ObjID.ACTIVATOR_ID), port, null, ssf);

            UnicastServerRef uref = new UnicastServerRef(lref);

            ref = uref;

            uref.exportObject(this, null, false);

        }

        public MarshalledObject<? extends Remote> activate(ActivationID id,

                                                           boolean force)

            throws ActivationException, UnknownObjectException, RemoteException

        {

            checkShutdown();

            return getGroupEntry(id).activate(id, force);

        }

    }

    class ActivationMonitorImpl extends UnicastRemoteObject

        implements ActivationMonitor

    {

        private static final long serialVersionUID = -6214940464757948867L;

        ActivationMonitorImpl(int port, RMIServerSocketFactory ssf)

            throws RemoteException

        {

            super(port, null, ssf);

        }

        public void inactiveObject(ActivationID id)

            throws UnknownObjectException, RemoteException

        {

            try {

                checkShutdown();

            } catch (ActivationException e) {

                return;

            }

            RegistryImpl.checkAccess("Activator.inactiveObject");

            getGroupEntry(id).inactiveObject(id);

        }

        public void activeObject(ActivationID id,

                                 MarshalledObject<? extends Remote> mobj)

            throws UnknownObjectException, RemoteException

        {

            try {

                checkShutdown();

            } catch (ActivationException e) {

                return;

            }

            RegistryImpl.checkAccess("ActivationSystem.activeObject");

            getGroupEntry(id).activeObject(id, mobj);

        }

        public void inactiveGroup(ActivationGroupID id,

                                  long incarnation)

            throws UnknownGroupException, RemoteException

        {

            try {

                checkShutdown();

            } catch (ActivationException e) {

                return;

            }

            RegistryImpl.checkAccess("ActivationMonitor.inactiveGroup");

            getGroupEntry(id).inactiveGroup(incarnation, false);

        }

    }

    /**

     * SameHostOnlyServerRef checks that access is from a local client

     * before the parameters are deserialized.  The unmarshalCustomCallData

     * hook is used to check the network address of the caller

     * with RegistryImpl.checkAccess().

     * The kind of access is retained for an exception if one is thrown.

     */

    static class SameHostOnlyServerRef extends UnicastServerRef {

        private static final long serialVersionUID = 1234L;

        private String accessKind;      // an exception message

        /**

         * Construct a new SameHostOnlyServerRef from a LiveRef.

         * @param lref a LiveRef

         */

        SameHostOnlyServerRef(LiveRef lref, String accessKind) {

            super(lref);

            this.accessKind = accessKind;

        }

        @Override

        protected void unmarshalCustomCallData(ObjectInput in) throws IOException, ClassNotFoundException {

            RegistryImpl.checkAccess(accessKind);

            super.unmarshalCustomCallData(in);

        }

    }