1 /* 2 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package sun.management.jdp; 26 27 import java.io.IOException; 28 import java.net.InetAddress; 29 import java.net.UnknownHostException; 30 import java.util.UUID; 31 32 import java.lang.management.ManagementFactory; 33 import java.lang.management.RuntimeMXBean; 34 import java.lang.reflect.Field; 35 import java.lang.reflect.Method; 36 import sun.management.VMManagement; 37 38 /** 39 * JdpController is responsible to create and manage a broadcast loop. 40 * 41 * <p> Other part of code has no access to broadcast loop and have to use 42 * provided static methods 43 * {@link #startDiscoveryService(InetAddress,int,String,String) startDiscoveryService} 44 * and {@link #stopDiscoveryService() stopDiscoveryService} 45 * <p>{@link #startDiscoveryService(InetAddress,int,String,String) startDiscoveryService} could be called multiple 46 * times as it stops the running service if it is necessary. 47 * Call to {@link #stopDiscoveryService() stopDiscoveryService} 48 * ignored if service isn't run. 49 * 50 * 51 * <p> System properties below could be used to control broadcast loop behavior. 52 * Property below have to be set explicitly in command line. It's not possible to 53 * set it in management.config file. Careless changes of these properties could 54 * lead to security or network issues. 55 * <ul> 56 * <li>com.sun.management.jdp.ttl - set ttl for broadcast packet</li> 57 * <li>com.sun.management.jdp.pause - set broadcast interval in seconds</li> 58 * <li>com.sun.management.jdp.source_addr - an address of interface to use for broadcast</li> 59 * </ul> 60 * 61 * <p>null parameters values are filtered out on {@link JdpPacketWriter} level and 62 * corresponding keys are not placed to packet. 63 */ 64 public final class JdpController { 65 66 private static class JDPControllerRunner implements Runnable { 67 68 private final JdpJmxPacket packet; 69 private final JdpBroadcaster bcast; 70 private final int pause; 71 private volatile boolean shutdown = false; 72 73 private JDPControllerRunner(JdpBroadcaster bcast, JdpJmxPacket packet, int pause) { 74 this.bcast = bcast; 75 this.packet = packet; 76 this.pause = pause; 77 } 78 79 @Override 80 public void run() { 81 try { 82 while (!shutdown) { 83 bcast.sendPacket(packet); 84 try { 85 Thread.sleep(this.pause); 86 } catch (InterruptedException e) { 87 // pass 88 } 89 } 90 91 } catch (IOException e) { 92 // pass; 93 } 94 95 // It's not possible to re-use controller, 96 // nevertheless reset shutdown variable 97 try { 98 stop(); 99 bcast.shutdown(); 100 } catch (IOException ex) { 101 // pass - ignore IOException during shutdown 102 } 103 } 104 105 public void stop() { 106 shutdown = true; 107 } 108 } 109 private static JDPControllerRunner controller = null; 110 111 private JdpController(){ 112 // Don't allow to instantiate this class. 113 } 114 115 // Utility to handle optional system properties 116 // Parse an integer from string or return default if provided string is null 117 private static int getInteger(String val, int dflt, String msg) throws JdpException { 118 try { 119 return (val == null) ? dflt : Integer.parseInt(val); 120 } catch (NumberFormatException ex) { 121 throw new JdpException(msg); 122 } 123 } 124 125 // Parse an inet address from string or return default if provided string is null 126 private static InetAddress getInetAddress(String val, InetAddress dflt, String msg) throws JdpException { 127 try { 128 return (val == null) ? dflt : InetAddress.getByName(val); 129 } catch (UnknownHostException ex) { 130 throw new JdpException(msg); 131 } 132 } 133 134 // Get the process id of the current running Java process 135 private static Integer getProcessId() { 136 try { 137 // Get the current process id using a reflection hack 138 RuntimeMXBean runtime = ManagementFactory.getRuntimeMXBean(); 139 Field jvm = runtime.getClass().getDeclaredField("jvm"); 140 jvm.setAccessible(true); 141 142 VMManagement mgmt = (sun.management.VMManagement) jvm.get(runtime); 143 Method pid_method = mgmt.getClass().getDeclaredMethod("getProcessId"); 144 pid_method.setAccessible(true); 145 Integer pid = (Integer) pid_method.invoke(mgmt); 146 return pid; 147 } catch(Exception ex) { 148 return null; 149 } 150 } 151 152 153 /** 154 * Starts discovery service 155 * 156 * @param address - multicast group address 157 * @param port - udp port to use 158 * @param instanceName - name of running JVM instance 159 * @param url - JMX service url 160 * @throws IOException 161 */ 162 public static synchronized void startDiscoveryService(InetAddress address, int port, String instanceName, String url) 163 throws IOException, JdpException { 164 165 // Limit packet to local subnet by default 166 int ttl = getInteger( 167 System.getProperty("com.sun.management.jdp.ttl"), 1, 168 "Invalid jdp packet ttl"); 169 170 // Broadcast once a 5 seconds by default 171 int pause = getInteger( 172 System.getProperty("com.sun.management.jdp.pause"), 5, 173 "Invalid jdp pause"); 174 175 // Converting seconds to milliseconds 176 pause = pause * 1000; 177 178 // Allow OS to choose broadcast source 179 InetAddress sourceAddress = getInetAddress( 180 System.getProperty("com.sun.management.jdp.source_addr"), null, 181 "Invalid source address provided"); 182 183 // Generate session id 184 UUID id = UUID.randomUUID(); 185 186 JdpJmxPacket packet = new JdpJmxPacket(id, url); 187 188 // Don't broadcast whole command line for security reason. 189 // Strip everything after first space 190 String javaCommand = System.getProperty("sun.java.command"); 191 if (javaCommand != null) { 192 String[] arr = javaCommand.split(" ", 2); 193 packet.setMainClass(arr[0]); 194 } 195 196 // Put optional explicit java instance name to packet, if user doesn't specify 197 // it the key is skipped. PacketWriter is responsible to skip keys having null value. 198 packet.setInstanceName(instanceName); 199 200 // Set rmi server hostname if it explicitly specified by user with 201 // java.rmi.server.hostname 202 String rmiHostname = System.getProperty("java.rmi.server.hostname"); 203 packet.setRmiHostname(rmiHostname); 204 205 // Set broadcast interval 206 packet.setBroadcastInterval(Integer.toString(pause)); 207 208 // Set process id 209 Integer pid = getProcessId(); 210 if (pid != null) { 211 packet.setProcessId(pid.toString()); 212 } 213 214 JdpBroadcaster bcast = new JdpBroadcaster(address, sourceAddress, port, ttl); 215 216 // Stop discovery service if it's already running 217 stopDiscoveryService(); 218 219 controller = new JDPControllerRunner(bcast, packet, pause); 220 221 Thread t = new Thread(null, controller, "JDP broadcaster", 0, false); 222 t.setDaemon(true); 223 t.start(); 224 } 225 226 /** 227 * Stop running discovery service, 228 * it's safe to attempt to stop not started service 229 */ 230 public static synchronized void stopDiscoveryService() { 231 if ( controller != null ){ 232 controller.stop(); 233 controller = null; 234 } 235 } 236 }