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 import sun.misc.ManagedLocalsThread;
38
39 /**
40 * JdpController is responsible to create and manage a broadcast loop
41 *
42 * <p> Other part of code has no access to broadcast loop and have to use
43 * provided static methods
44 * {@link #startDiscoveryService(InetAddress,int,String,String) startDiscoveryService}
45 * and {@link #stopDiscoveryService() stopDiscoveryService}</p>
46 * <p>{@link #startDiscoveryService(InetAddress,int,String,String) startDiscoveryService} could be called multiple
47 * times as it stops the running service if it is necessary. Call to {@link #stopDiscoveryService() stopDiscoveryService}
48 * ignored if service isn't run</p>
49 *
50 *
51 * </p>
52 *
53 * <p> System properties below could be used to control broadcast loop behavior.
54 * Property below have to be set explicitly in command line. It's not possible to
55 * set it in management.config file. Careless changes of these properties could
56 * lead to security or network issues.
57 * <ul>
58 * <li>com.sun.management.jdp.ttl - set ttl for broadcast packet</li>
59 * <li>com.sun.management.jdp.pause - set broadcast interval in seconds</li>
60 * <li>com.sun.management.jdp.source_addr - an address of interface to use for broadcast</li>
61 * </ul>
62 </p>
63 * <p>null parameters values are filtered out on {@link JdpPacketWriter} level and
64 * corresponding keys are not placed to packet.</p>
65 */
66 public final class JdpController {
67
68 private static class JDPControllerRunner implements Runnable {
69
70 private final JdpJmxPacket packet;
71 private final JdpBroadcaster bcast;
72 private final int pause;
73 private volatile boolean shutdown = false;
74
75 private JDPControllerRunner(JdpBroadcaster bcast, JdpJmxPacket packet, int pause) {
76 this.bcast = bcast;
77 this.packet = packet;
78 this.pause = pause;
79 }
80
81 @Override
82 public void run() {
83 try {
84 while (!shutdown) {
85 bcast.sendPacket(packet);
86 try {
87 Thread.sleep(this.pause);
88 } catch (InterruptedException e) {
89 // pass
90 }
91 }
92
93 } catch (IOException e) {
94 // pass;
95 }
96
97 // It's not possible to re-use controller,
98 // nevertheless reset shutdown variable
99 try {
100 stop();
101 bcast.shutdown();
102 } catch (IOException ex) {
103 // pass - ignore IOException during shutdown
104 }
105 }
106
107 public void stop() {
108 shutdown = true;
109 }
110 }
111 private static JDPControllerRunner controller = null;
112
113 private JdpController(){
114 // Don't allow to instantiate this class.
115 }
116
117 // Utility to handle optional system properties
118 // Parse an integer from string or return default if provided string is null
119 private static int getInteger(String val, int dflt, String msg) throws JdpException {
120 try {
121 return (val == null) ? dflt : Integer.parseInt(val);
122 } catch (NumberFormatException ex) {
123 throw new JdpException(msg);
124 }
125 }
126
127 // Parse an inet address from string or return default if provided string is null
128 private static InetAddress getInetAddress(String val, InetAddress dflt, String msg) throws JdpException {
129 try {
130 return (val == null) ? dflt : InetAddress.getByName(val);
131 } catch (UnknownHostException ex) {
132 throw new JdpException(msg);
133 }
134 }
135
136 // Get the process id of the current running Java process
137 private static Integer getProcessId() {
138 try {
139 // Get the current process id using a reflection hack
140 RuntimeMXBean runtime = ManagementFactory.getRuntimeMXBean();
141 Field jvm = runtime.getClass().getDeclaredField("jvm");
142 jvm.setAccessible(true);
143
144 VMManagement mgmt = (sun.management.VMManagement) jvm.get(runtime);
145 Method pid_method = mgmt.getClass().getDeclaredMethod("getProcessId");
146 pid_method.setAccessible(true);
147 Integer pid = (Integer) pid_method.invoke(mgmt);
148 return pid;
149 } catch(Exception ex) {
150 return null;
151 }
152 }
153
154
155 /**
156 * Starts discovery service
157 *
158 * @param address - multicast group address
159 * @param port - udp port to use
160 * @param instanceName - name of running JVM instance
161 * @param url - JMX service url
162 * @throws IOException
163 */
164 public static synchronized void startDiscoveryService(InetAddress address, int port, String instanceName, String url)
165 throws IOException, JdpException {
166
167 // Limit packet to local subnet by default
168 int ttl = getInteger(
169 System.getProperty("com.sun.management.jdp.ttl"), 1,
170 "Invalid jdp packet ttl");
171
172 // Broadcast once a 5 seconds by default
173 int pause = getInteger(
174 System.getProperty("com.sun.management.jdp.pause"), 5,
175 "Invalid jdp pause");
176
177 // Converting seconds to milliseconds
178 pause = pause * 1000;
179
180 // Allow OS to choose broadcast source
181 InetAddress sourceAddress = getInetAddress(
182 System.getProperty("com.sun.management.jdp.source_addr"), null,
183 "Invalid source address provided");
184
185 // Generate session id
186 UUID id = UUID.randomUUID();
187
188 JdpJmxPacket packet = new JdpJmxPacket(id, url);
189
190 // Don't broadcast whole command line for security reason.
191 // Strip everything after first space
192 String javaCommand = System.getProperty("sun.java.command");
193 if (javaCommand != null) {
194 String[] arr = javaCommand.split(" ", 2);
195 packet.setMainClass(arr[0]);
196 }
197
198 // Put optional explicit java instance name to packet, if user doesn't specify
199 // it the key is skipped. PacketWriter is responsible to skip keys having null value.
200 packet.setInstanceName(instanceName);
201
202 // Set rmi server hostname if it explicitly specified by user with
203 // java.rmi.server.hostname
204 String rmiHostname = System.getProperty("java.rmi.server.hostname");
205 packet.setRmiHostname(rmiHostname);
206
207 // Set broadcast interval
208 packet.setBroadcastInterval(Integer.toString(pause));
209
210 // Set process id
211 Integer pid = getProcessId();
212 if (pid != null) {
213 packet.setProcessId(pid.toString());
214 }
215
216 JdpBroadcaster bcast = new JdpBroadcaster(address, sourceAddress, port, ttl);
217
218 // Stop discovery service if it's already running
219 stopDiscoveryService();
220
221 controller = new JDPControllerRunner(bcast, packet, pause);
222
223 Thread t = new ManagedLocalsThread(controller, "JDP broadcaster");
224 t.setDaemon(true);
225 t.start();
226 }
227
228 /**
229 * Stop running discovery service,
230 * it's safe to attempt to stop not started service
231 */
232 public static synchronized void stopDiscoveryService() {
233 if ( controller != null ){
234 controller.stop();
235 controller = null;
236 }
237 }
238 }