/*

 * Copyright (c) 1996, 2008, 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.registry;

import java.util.Enumeration;

import java.util.Hashtable;

import java.util.MissingResourceException;

import java.util.ResourceBundle;

import java.io.IOException;

import java.net.*;

import java.rmi.*;

import java.rmi.server.ObjID;

import java.rmi.server.RemoteServer;

import java.rmi.server.ServerNotActiveException;

import java.rmi.registry.Registry;

import java.rmi.server.RMIClientSocketFactory;

import java.rmi.server.RMIServerSocketFactory;

import java.security.AccessControlContext;

import java.security.AccessController;

import java.security.CodeSource;

import java.security.Policy;

import java.security.PrivilegedActionException;

import java.security.PrivilegedExceptionAction;

import java.security.PermissionCollection;

import java.security.Permissions;

import java.security.ProtectionDomain;

import java.text.MessageFormat;

import sun.rmi.server.LoaderHandler;

import sun.rmi.server.UnicastServerRef;

import sun.rmi.server.UnicastServerRef2;

import sun.rmi.transport.LiveRef;

import sun.rmi.transport.ObjectTable;

import sun.rmi.transport.Target;

import sun.security.action.GetPropertyAction;

/**

 * A "registry" exists on every node that allows RMI connections to

 * servers on that node.  The registry on a particular node contains a

 * transient database that maps names to remote objects.  When the

 * node boots, the registry database is empty.  The names stored in the

 * registry are pure and are not parsed.  A service storing itself in

 * the registry may want to prefix its name of the service by a package

 * name (although not required), to reduce name collisions in the

 * registry.

 *

 * The LocateRegistry class is used to obtain registry for different hosts.

 *

 * @see java.rmi.registry.LocateRegistry

 */

public class RegistryImpl extends java.rmi.server.RemoteServer

        implements Registry

{

    /* indicate compatibility with JDK 1.1.x version of class */

    private static final long serialVersionUID = 4666870661827494597L;

    private Hashtable<String, Remote> bindings

        = new Hashtable<String, Remote>(101);

    private static Hashtable<InetAddress, InetAddress> allowedAccessCache

        = new Hashtable<InetAddress, InetAddress>(3);

    private static RegistryImpl registry;

    private static ObjID id = new ObjID(ObjID.REGISTRY_ID);

    private static ResourceBundle resources = null;

    /**

     * Construct a new RegistryImpl on the specified port with the

     * given custom socket factory pair.

     */

    public RegistryImpl(int port,

                        RMIClientSocketFactory csf,

                        RMIServerSocketFactory ssf)

        throws RemoteException

    {

        LiveRef lref = new LiveRef(id, port, csf, ssf);

        setup(new UnicastServerRef2(lref));

    }

    /**

     * Construct a new RegistryImpl on the specified port.

     */

    public RegistryImpl(int port)

        throws RemoteException

    {

        LiveRef lref = new LiveRef(id, port);

        setup(new UnicastServerRef(lref));

    }

    /*

     * Create the export the object using the parameter

     * <code>uref</code>

     */

    private void setup(UnicastServerRef uref)

        throws RemoteException

    {

        /* Server ref must be created and assigned before remote

         * object 'this' can be exported.

         */

        ref = uref;

        uref.exportObject(this, null, true);

    }

    /**

     * Returns the remote object for specified name in the registry.

     * @exception RemoteException If remote operation failed.

     * @exception NotBound If name is not currently bound.

     */

    public Remote lookup(String name)

        throws RemoteException, NotBoundException

    {

        synchronized (bindings) {

            Remote obj = bindings.get(name);

            if (obj == null)

                throw new NotBoundException(name);

            return obj;

        }

    }

    /**

     * Binds the name to the specified remote object.

     * @exception RemoteException If remote operation failed.

     * @exception AlreadyBoundException If name is already bound.

     */

    public void bind(String name, Remote obj)

        throws RemoteException, AlreadyBoundException, AccessException

    {

        checkAccess("Registry.bind");

        synchronized (bindings) {

            Remote curr = bindings.get(name);

            if (curr != null)

                throw new AlreadyBoundException(name);

            bindings.put(name, obj);

        }

    }

    /**

     * Unbind the name.

     * @exception RemoteException If remote operation failed.

     * @exception NotBound If name is not currently bound.

     */

    public void unbind(String name)

        throws RemoteException, NotBoundException, AccessException

    {

        checkAccess("Registry.unbind");

        synchronized (bindings) {

            Remote obj = bindings.get(name);

            if (obj == null)

                throw new NotBoundException(name);

            bindings.remove(name);

        }

    }

    /**

     * Rebind the name to a new object, replaces any existing binding.

     * @exception RemoteException If remote operation failed.

     */

    public void rebind(String name, Remote obj)

        throws RemoteException, AccessException

    {

        checkAccess("Registry.rebind");

        bindings.put(name, obj);

    }

    /**

     * Returns an enumeration of the names in the registry.

     * @exception RemoteException If remote operation failed.

     */

    public String[] list()

        throws RemoteException

    {

        String[] names;

        synchronized (bindings) {

            int i = bindings.size();

            names = new String[i];

            Enumeration enum_ = bindings.keys();

            while ((--i) >= 0)

                names[i] = (String)enum_.nextElement();

        }

        return names;

    }

    /**

     * Check that the caller has access to perform indicated operation.

     * The client must be on same the same host as this server.

     */

    public static void checkAccess(String op) throws AccessException {

        try {

            /*

             * Get client host that this registry operation was made from.

             */

            final String clientHostName = getClientHost();

            InetAddress clientHost;

            try {

                clientHost = java.security.AccessController.doPrivileged(

                    new java.security.PrivilegedExceptionAction<InetAddress>() {

                        public InetAddress run()

                            throws java.net.UnknownHostException

                        {

                            return InetAddress.getByName(clientHostName);

                        }

                    });

            } catch (PrivilegedActionException pae) {

                throw (java.net.UnknownHostException) pae.getException();

            }

            // if client not yet seen, make sure client allowed access

            if (allowedAccessCache.get(clientHost) == null) {

                if (clientHost.isAnyLocalAddress()) {

                    throw new AccessException(

                        "Registry." + op + " disallowed; origin unknown");

                }

                try {

                    final InetAddress finalClientHost = clientHost;

                    java.security.AccessController.doPrivileged(

                        new java.security.PrivilegedExceptionAction<Void>() {

                            public Void run() throws java.io.IOException {

                                /*

                                 * if a ServerSocket can be bound to the client's

                                 * address then that address must be local

                                 */

                                (new ServerSocket(0, 10, finalClientHost)).close();

                                allowedAccessCache.put(finalClientHost,

                                                       finalClientHost);

                                return null;

                            }

                    });

                } catch (PrivilegedActionException pae) {

                    // must have been an IOException

                    throw new AccessException(

                        "Registry." + op + " disallowed; origin " +

                        clientHost + " is non-local host");

                }

            }

        } catch (ServerNotActiveException ex) {

            /*

             * Local call from this VM: allow access.

             */

        } catch (java.net.UnknownHostException ex) {

            throw new AccessException("Registry." + op +

                                      " disallowed; origin is unknown host");

        }

    }

    public static ObjID getID() {

        return id;

    }

    /**

     * Retrieves text resources from the locale-specific properties file.

     */

    private static String getTextResource(String key) {

        if (resources == null) {

            try {

                resources = ResourceBundle.getBundle(

                    "sun.rmi.registry.resources.rmiregistry");

            } catch (MissingResourceException mre) {

            }

            if (resources == null) {

                // throwing an Error is a bit extreme, methinks

                return ("[missing resource file: " + key + "]");

            }

        }

        String val = null;

        try {

            val = resources.getString(key);

        } catch (MissingResourceException mre) {

        }

        if (val == null) {

            return ("[missing resource: " + key + "]");

        } else {

            return (val);

        }

    }

    /**

     * Main program to start a registry. <br>

     * The port number can be specified on the command line.

     */

    public static void main(String args[])

    {

        // Create and install the security manager if one is not installed

        // already.

        if (System.getSecurityManager() == null) {

            System.setSecurityManager(new RMISecurityManager());

        }

        try {

            /*

             * Fix bugid 4147561: When JDK tools are executed, the value of

             * the CLASSPATH environment variable for the shell in which they

             * were invoked is no longer incorporated into the application

             * class path; CLASSPATH's only effect is to be the value of the

             * system property "env.class.path".  To preserve the previous

             * (JDK1.1 and JDK1.2beta3) behavior of this tool, however, its

             * CLASSPATH should still be considered when resolving classes

             * being unmarshalled.  To effect this old behavior, a class

             * loader that loads from the file path specified in the

             * "env.class.path" property is created and set to be the context

             * class loader before the remote object is exported.

             */

            String envcp = System.getProperty("env.class.path");

            if (envcp == null) {

                envcp = ".";            // preserve old default behavior

            }

            URL[] urls = sun.misc.URLClassPath.pathToURLs(envcp);

            ClassLoader cl = new URLClassLoader(urls);

            String codebaseProperty = null;

            String prop = java.security.AccessController.doPrivileged(

                new GetPropertyAction("java.rmi.server.codebase"));

            if (prop != null && prop.trim().length() > 0) {

                codebaseProperty = prop;

            }

            URL[] codebaseURLs = null;

            if (codebaseProperty != null) {

                codebaseURLs = sun.misc.URLClassPath.pathToURLs(codebaseProperty);

            } else {

                codebaseURLs = new URL[0];

            }

            /*

             * Fix bugid 4242317: Classes defined by this class loader should

             * be annotated with the value of the "java.rmi.server.codebase"

             * property, not the "file:" URLs for the CLASSPATH elements.

             */

            sun.rmi.server.LoaderHandler.registerCodebaseLoader(cl);

            Thread.currentThread().setContextClassLoader(cl);

            final int regPort = (args.length >= 1) ? Integer.parseInt(args[0])

                                                   : Registry.REGISTRY_PORT;

            try {

                registry = AccessController.doPrivileged(

                    new PrivilegedExceptionAction<RegistryImpl>() {

                        public RegistryImpl run() throws RemoteException {

                            return new RegistryImpl(regPort);

                        }

                    }, getAccessControlContext(codebaseURLs));

            } catch (PrivilegedActionException ex) {

                throw (RemoteException) ex.getException();

            }

            // prevent registry from exiting

            while (true) {

                try {

                    Thread.sleep(Long.MAX_VALUE);

                } catch (InterruptedException e) {

                }

            }

        } catch (NumberFormatException e) {

            System.err.println(MessageFormat.format(

                getTextResource("rmiregistry.port.badnumber"),

                args[0] ));

            System.err.println(MessageFormat.format(

                getTextResource("rmiregistry.usage"),

                "rmiregistry" ));

        } catch (Exception e) {

            e.printStackTrace();

        }

        System.exit(1);

    }

    /**

     * Generates an AccessControlContext from several URLs.

     * The approach used here is taken from the similar method

     * getAccessControlContext() in the sun.applet.AppletPanel class.

     */

    private static AccessControlContext getAccessControlContext(URL[] urls) {

        // begin with permissions granted to all code in current policy

        PermissionCollection perms = AccessController.doPrivileged(

            new java.security.PrivilegedAction<PermissionCollection>() {

                public PermissionCollection run() {

                    CodeSource codesource = new CodeSource(null,

                        (java.security.cert.Certificate[]) null);

                    Policy p = java.security.Policy.getPolicy();

                    if (p != null) {

                        return p.getPermissions(codesource);

                    } else {

                        return new Permissions();

                    }

                }

            });

        /*

         * Anyone can connect to the registry and the registry can connect

         * to and possibly download stubs from anywhere. Downloaded stubs and

         * related classes themselves are more tightly limited by RMI.

         */

        perms.add(new SocketPermission("*", "connect,accept"));

        // add permissions required to load from codebase URL path

        LoaderHandler.addPermissionsForURLs(urls, perms, false);

        /*

         * Create an AccessControlContext that consists of a single

         * protection domain with only the permissions calculated above.

         */

        ProtectionDomain pd = new ProtectionDomain(

            new CodeSource((urls.length > 0 ? urls[0] : null),

                (java.security.cert.Certificate[]) null),

            perms);

        return new AccessControlContext(new ProtectionDomain[] { pd });

    }

}