| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.felix.shell.remote; |
| |
| import java.io.IOException; |
| import java.io.PrintStream; |
| import java.net.InetAddress; |
| import java.net.ServerSocket; |
| import java.net.Socket; |
| import java.net.SocketException; |
| import java.net.SocketTimeoutException; |
| import java.util.HashSet; |
| import java.util.Set; |
| |
| import org.osgi.framework.BundleContext; |
| |
| /** |
| * Implements a simple listener that will accept a single connection. |
| */ |
| class Listener |
| { |
| private final int m_port; |
| private final String m_ip; |
| private final Thread m_listenerThread; |
| private final Acceptor m_acceptor; |
| private final AtomicInteger m_useCounter; |
| private final int m_maxConnections; |
| private final int m_soTimeout; |
| private final Set m_connections; |
| private final ServiceMediator m_services; |
| |
| /** |
| * Activates this listener on a listener thread (telnetconsole.Listener). |
| */ |
| public Listener(BundleContext context, ServiceMediator services) throws IOException |
| { |
| m_services = services; |
| //configure from framework property |
| m_ip = getProperty(context, "osgi.shell.telnet.ip", "127.0.0.1"); |
| m_port = getProperty(context, "osgi.shell.telnet.port", 6666); |
| m_soTimeout = getProperty(context, "osgi.shell.telnet.socketTimeout", 0); |
| m_maxConnections = getProperty(context, "osgi.shell.telnet.maxconn", 2); |
| m_useCounter = new AtomicInteger(0); |
| m_connections = new HashSet(); |
| m_acceptor = new Acceptor(); |
| m_listenerThread = new Thread(m_acceptor, "telnetconsole.Listener"); |
| m_listenerThread.start(); |
| }//activate |
| |
| public ServiceMediator getServices() |
| { |
| return m_services; |
| } |
| |
| /** |
| * Deactivates this listener. |
| * <p/> |
| * The listener's socket will be closed, which should cause an interrupt in the |
| * listener thread and allow for it to return. The calling thread joins the listener |
| * thread until it returns (to ensure a clean stop). |
| */ |
| public void deactivate() |
| { |
| try |
| { |
| //wait for the listener thread |
| m_acceptor.close(); |
| m_listenerThread.join(); |
| } |
| catch (Exception ex) |
| { |
| m_services.error("Listener::deactivate()", ex); |
| } |
| |
| // get the active connections (and clear the list) |
| // we have to work on a copy, since stopping any active connection |
| // will try to remove itself from the set, which might cause a |
| // ConcurrentModificationException if we would iterate over the list |
| Shell[] connections; |
| synchronized (m_connections) |
| { |
| connections = (Shell[]) m_connections.toArray(new Shell[m_connections.size()]); |
| m_connections.clear(); |
| } |
| |
| // now terminate all active connections |
| for (int i = 0; i < connections.length; i++) |
| { |
| connections[i].terminate(); |
| } |
| }//deactivate |
| |
| /** |
| * Class that implements the listener's accept logic as a <tt>Runnable</tt>. |
| */ |
| private class Acceptor implements Runnable |
| { |
| private volatile boolean m_stop = false; |
| private final ServerSocket m_serverSocket; |
| |
| Acceptor() throws IOException |
| { |
| m_serverSocket = new ServerSocket(m_port, 1, InetAddress.getByName(m_ip)); |
| m_serverSocket.setSoTimeout(m_soTimeout); |
| } |
| |
| public void close() throws IOException |
| { |
| m_stop = true; |
| m_serverSocket.close(); |
| } |
| |
| /** |
| * Listens constantly to a server socket and handles incoming connections. |
| * One connection will be accepted and routed into the shell, all others will |
| * be notified and closed. |
| * <p/> |
| * The mechanism that should allow the thread to unblock from the ServerSocket.accept() call |
| * is currently closing the ServerSocket from another thread. When the stop flag is set, |
| * this should cause the thread to return and stop. |
| */ |
| public void run() |
| { |
| try |
| { |
| /* |
| A server socket is opened with a connectivity queue of a size specified |
| in int floodProtection. Concurrent login handling under normal circumstances |
| should be handled properly, but denial of service attacks via massive parallel |
| program logins should be prevented with this. |
| */ |
| do |
| { |
| try |
| { |
| Socket s = m_serverSocket.accept(); |
| if (m_useCounter.get() >= m_maxConnections) |
| { |
| //reject with message |
| PrintStream out = new PrintStream(s.getOutputStream()); |
| out.print(INUSE_MESSAGE); |
| out.flush(); |
| //close |
| out.close(); |
| s.close(); |
| } |
| else |
| { |
| m_useCounter.increment(); |
| //run on the connection thread |
| Thread connectionThread = new Thread(new Shell(Listener.this, s, m_useCounter)); |
| connectionThread.setName("telnetconsole.shell remote=" + s.getRemoteSocketAddress()); |
| connectionThread.start(); |
| } |
| } |
| catch (SocketException ex) |
| { |
| } |
| catch (SocketTimeoutException ste) |
| { |
| // Caught socket timeout exception. continue |
| } |
| } |
| while (!m_stop); |
| |
| } |
| catch (IOException e) |
| { |
| m_services.error("Listener.Acceptor::run()", e); |
| } |
| }//run |
| }//inner class Acceptor |
| |
| private static final String INUSE_MESSAGE = "Connection refused.\r\n" + "All possible connections are currently being used.\r\n"; |
| |
| private int getProperty(BundleContext bundleContext, String propName, int defaultValue) |
| { |
| String propValue = bundleContext.getProperty(propName); |
| if (propValue != null) |
| { |
| try |
| { |
| return Integer.parseInt(propValue); |
| } |
| catch (NumberFormatException ex) |
| { |
| m_services.error("Listener::activate()", ex); |
| } |
| } |
| |
| return defaultValue; |
| } |
| |
| private String getProperty(BundleContext bundleContext, String propName, String defaultValue) |
| { |
| String propValue = bundleContext.getProperty(propName); |
| if (propValue != null) |
| { |
| return propValue; |
| } |
| |
| return defaultValue; |
| } |
| |
| /** |
| * Registers the given {@link Shell} instance handling a remote connection |
| * to this listener. |
| * <p> |
| * This method is called by the {@link Shell#run()} method to register the |
| * remote connection for it to be terminated in case this listener is |
| * {@link #deactivate() deactivated} before the remote connection is |
| * terminated. |
| * |
| * @param connection The {@link Shell} connection to register |
| */ |
| void registerConnection(Shell connection) |
| { |
| synchronized (m_connections) |
| { |
| m_connections.add(connection); |
| } |
| } |
| |
| /** |
| * Unregisters the given {@link Shell} instance handling a remote connection |
| * from this listener. |
| * <p> |
| * This method is called when the {@link Shell#run()} method terminates to |
| * inform this listener instance that the remote connection has ended and |
| * thus does not need to be cleaned up when this listener terminates. |
| * |
| * @param connection The {@link Shell} connection to unregister |
| */ |
| void unregisterConnection(Shell connection) |
| { |
| synchronized (m_connections) |
| { |
| m_connections.remove(connection); |
| } |
| } |
| }//class Listener |