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}
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.
48 * Call to {@link #stopDiscoveryService() stopDiscoveryService}
49 * ignored if service isn't run.
50 *
51 *
52 * <p> System properties below could be used to control broadcast loop behavior.
53 * Property below have to be set explicitly in command line. It's not possible to
54 * set it in management.config file. Careless changes of these properties could
55 * lead to security or network issues.
56 * <ul>
57 * <li>com.sun.management.jdp.ttl - set ttl for broadcast packet</li>
58 * <li>com.sun.management.jdp.pause - set broadcast interval in seconds</li>
59 * <li>com.sun.management.jdp.source_addr - an address of interface to use for broadcast</li>
60 * </ul>
61 *
62 * <p>null parameters values are filtered out on {@link JdpPacketWriter} level and
63 * corresponding keys are not placed to packet.
64 */
65 public final class JdpController {
66
67 private static class JDPControllerRunner implements Runnable {
68
69 private final JdpJmxPacket packet;
70 private final JdpBroadcaster bcast;
71 private final int pause;
72 private volatile boolean shutdown = false;
73
74 private JDPControllerRunner(JdpBroadcaster bcast, JdpJmxPacket packet, int pause) {
75 this.bcast = bcast;
76 this.packet = packet;
77 this.pause = pause;
78 }
79
80 @Override
81 public void run() {
82 try {
83 while (!shutdown) {
84 bcast.sendPacket(packet);
85 try {
86 Thread.sleep(this.pause);
87 } catch (InterruptedException e) {
88 // pass
89 }
90 }
91
92 } catch (IOException e) {
93 // pass;
94 }
95
96 // It's not possible to re-use controller,
97 // nevertheless reset shutdown variable
98 try {
99 stop();
100 bcast.shutdown();
101 } catch (IOException ex) {
102 // pass - ignore IOException during shutdown
103 }
104 }
105
106 public void stop() {
107 shutdown = true;
108 }
109 }
110 private static JDPControllerRunner controller = null;
111
112 private JdpController(){
113 // Don't allow to instantiate this class.
114 }
115
116 // Utility to handle optional system properties
117 // Parse an integer from string or return default if provided string is null
118 private static int getInteger(String val, int dflt, String msg) throws JdpException {
119 try {
120 return (val == null) ? dflt : Integer.parseInt(val);
121 } catch (NumberFormatException ex) {
122 throw new JdpException(msg);
123 }
124 }
125
126 // Parse an inet address from string or return default if provided string is null
127 private static InetAddress getInetAddress(String val, InetAddress dflt, String msg) throws JdpException {
128 try {
129 return (val == null) ? dflt : InetAddress.getByName(val);
130 } catch (UnknownHostException ex) {
131 throw new JdpException(msg);
132 }
133 }
134
135 // Get the process id of the current running Java process
136 private static Integer getProcessId() {
137 try {
138 // Get the current process id using a reflection hack
139 RuntimeMXBean runtime = ManagementFactory.getRuntimeMXBean();
140 Field jvm = runtime.getClass().getDeclaredField("jvm");
141 jvm.setAccessible(true);
142
143 VMManagement mgmt = (sun.management.VMManagement) jvm.get(runtime);
144 Method pid_method = mgmt.getClass().getDeclaredMethod("getProcessId");
145 pid_method.setAccessible(true);
146 Integer pid = (Integer) pid_method.invoke(mgmt);
147 return pid;
148 } catch(Exception ex) {
149 return null;
150 }
151 }
152
153
154 /**
155 * Starts discovery service
156 *
157 * @param address - multicast group address
158 * @param port - udp port to use
159 * @param instanceName - name of running JVM instance
160 * @param url - JMX service url
161 * @throws IOException
162 */
163 public static synchronized void startDiscoveryService(InetAddress address, int port, String instanceName, String url)
164 throws IOException, JdpException {
165
166 // Limit packet to local subnet by default
167 int ttl = getInteger(
168 System.getProperty("com.sun.management.jdp.ttl"), 1,
169 "Invalid jdp packet ttl");
170
171 // Broadcast once a 5 seconds by default
172 int pause = getInteger(
173 System.getProperty("com.sun.management.jdp.pause"), 5,
174 "Invalid jdp pause");
175
176 // Converting seconds to milliseconds
177 pause = pause * 1000;
178
179 // Allow OS to choose broadcast source
180 InetAddress sourceAddress = getInetAddress(
181 System.getProperty("com.sun.management.jdp.source_addr"), null,
182 "Invalid source address provided");
183
184 // Generate session id
185 UUID id = UUID.randomUUID();
186
187 JdpJmxPacket packet = new JdpJmxPacket(id, url);
188
189 // Don't broadcast whole command line for security reason.
190 // Strip everything after first space
191 String javaCommand = System.getProperty("sun.java.command");
192 if (javaCommand != null) {
193 String[] arr = javaCommand.split(" ", 2);
194 packet.setMainClass(arr[0]);
195 }
196
197 // Put optional explicit java instance name to packet, if user doesn't specify
198 // it the key is skipped. PacketWriter is responsible to skip keys having null value.
199 packet.setInstanceName(instanceName);
200
201 // Set rmi server hostname if it explicitly specified by user with
202 // java.rmi.server.hostname
203 String rmiHostname = System.getProperty("java.rmi.server.hostname");
204 packet.setRmiHostname(rmiHostname);
205
206 // Set broadcast interval
207 packet.setBroadcastInterval(Integer.toString(pause));
208
209 // Set process id
210 Integer pid = getProcessId();
211 if (pid != null) {
212 packet.setProcessId(pid.toString());
213 }
214
215 JdpBroadcaster bcast = new JdpBroadcaster(address, sourceAddress, port, ttl);
216
217 // Stop discovery service if it's already running
218 stopDiscoveryService();
219
220 controller = new JDPControllerRunner(bcast, packet, pause);
221
222 Thread t = new ManagedLocalsThread(controller, "JDP broadcaster");
223 t.setDaemon(true);
224 t.start();
225 }
226
227 /**
228 * Stop running discovery service,
229 * it's safe to attempt to stop not started service
230 */
231 public static synchronized void stopDiscoveryService() {
232 if ( controller != null ){
233 controller.stop();
234 controller = null;
235 }
236 }
237 }