1 /*
2 * Copyright (c) 2013, 2018, 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
26 package sun.management.jdp;
27
28 import java.io.IOException;
29 import java.lang.management.ManagementFactory;
30 import java.lang.management.RuntimeMXBean;
31 import java.lang.reflect.Field;
32 import java.lang.reflect.Method;
33 import java.net.InetAddress;
34 import java.net.UnknownHostException;
35 import java.util.UUID;
36
37 /**
38 * JdpController is responsible to create and manage a broadcast loop.
39 *
40 * <p> Other part of code has no access to broadcast loop and have to use
41 * provided static methods
42 * {@link #startDiscoveryService(InetAddress,int,String,String) startDiscoveryService}
43 * and {@link #stopDiscoveryService() stopDiscoveryService}
44 * <p>{@link #startDiscoveryService(InetAddress,int,String,String) startDiscoveryService} could be called multiple
45 * times as it stops the running service if it is necessary.
46 * Call to {@link #stopDiscoveryService() stopDiscoveryService}
47 * ignored if service isn't run.
48 *
49 *
50 * <p> System properties below could be used to control broadcast loop behavior.
51 * Property below have to be set explicitly in command line. It's not possible to
52 * set it in management.config file. Careless changes of these properties could
53 * lead to security or network issues.
54 * <ul>
55 * <li>com.sun.management.jdp.ttl - set ttl for broadcast packet</li>
56 * <li>com.sun.management.jdp.pause - set broadcast interval in seconds</li>
57 * <li>com.sun.management.jdp.source_addr - an address of interface to use for broadcast</li>
58 * </ul>
59 *
60 * <p>null parameters values are filtered out on {@link JdpPacketWriter} level and
61 * corresponding keys are not placed to packet.
62 */
63 public final class JdpController {
64
65 private static class JDPControllerRunner implements Runnable {
66
67 private final JdpJmxPacket packet;
68 private final JdpBroadcaster bcast;
69 private final int pause;
70 private volatile boolean shutdown = false;
71
72 private JDPControllerRunner(JdpBroadcaster bcast, JdpJmxPacket packet, int pause) {
73 this.bcast = bcast;
74 this.packet = packet;
75 this.pause = pause;
76 }
77
78 @Override
79 public void run() {
80 try {
81 while (!shutdown) {
82 bcast.sendPacket(packet);
83 try {
84 Thread.sleep(this.pause);
85 } catch (InterruptedException e) {
86 // pass
87 }
88 }
89
90 } catch (IOException e) {
91 // pass;
92 }
93
94 // It's not possible to re-use controller,
95 // nevertheless reset shutdown variable
96 try {
97 stop();
98 bcast.shutdown();
99 } catch (IOException ex) {
100 // pass - ignore IOException during shutdown
101 }
102 }
103
104 public void stop() {
105 shutdown = true;
106 }
107 }
108 private static JDPControllerRunner controller = null;
109
110 private JdpController(){
111 // Don't allow to instantiate this class.
112 }
113
114 // Utility to handle optional system properties
115 // Parse an integer from string or return default if provided string is null
116 private static int getInteger(String val, int dflt, String msg) throws JdpException {
117 try {
118 return (val == null) ? dflt : Integer.parseInt(val);
119 } catch (NumberFormatException ex) {
120 throw new JdpException(msg);
121 }
122 }
123
124 // Parse an inet address from string or return default if provided string is null
125 private static InetAddress getInetAddress(String val, InetAddress dflt, String msg) throws JdpException {
126 try {
127 return (val == null) ? dflt : InetAddress.getByName(val);
128 } catch (UnknownHostException ex) {
129 throw new JdpException(msg);
130 }
131 }
132
133 // Get the process id of the current running Java process
134 private static Long getProcessId() {
135 try {
136 // Get the current process id
137 return ProcessHandle.current().pid();
138 } catch(UnsupportedOperationException ex) {
139 return null;
140 }
141 }
142
143
144 /**
145 * Starts discovery service
146 *
147 * @param address - multicast group address
148 * @param port - udp port to use
149 * @param instanceName - name of running JVM instance
150 * @param url - JMX service url
151 * @throws IOException
152 */
153 public static synchronized void startDiscoveryService(InetAddress address, int port, String instanceName, String url)
154 throws IOException, JdpException {
155
156 // Limit packet to local subnet by default
157 int ttl = getInteger(
158 System.getProperty("com.sun.management.jdp.ttl"), 1,
159 "Invalid jdp packet ttl");
160
161 // Broadcast once a 5 seconds by default
162 int pause = getInteger(
163 System.getProperty("com.sun.management.jdp.pause"), 5,
164 "Invalid jdp pause");
165
166 // Converting seconds to milliseconds
167 pause = pause * 1000;
168
169 // Allow OS to choose broadcast source
170 InetAddress sourceAddress = getInetAddress(
171 System.getProperty("com.sun.management.jdp.source_addr"), null,
172 "Invalid source address provided");
173
174 // Generate session id
175 UUID id = UUID.randomUUID();
176
177 JdpJmxPacket packet = new JdpJmxPacket(id, url);
178
179 // Don't broadcast whole command line for security reason.
180 // Strip everything after first space
181 String javaCommand = System.getProperty("sun.java.command");
182 if (javaCommand != null) {
183 String[] arr = javaCommand.split(" ", 2);
184 packet.setMainClass(arr[0]);
185 }
186
187 // Put optional explicit java instance name to packet, if user doesn't specify
188 // it the key is skipped. PacketWriter is responsible to skip keys having null value.
189 packet.setInstanceName(instanceName);
190
191 // Set rmi server hostname if it explicitly specified by user with
192 // java.rmi.server.hostname
193 String rmiHostname = System.getProperty("java.rmi.server.hostname");
194 packet.setRmiHostname(rmiHostname);
195
196 // Set broadcast interval
197 packet.setBroadcastInterval(Integer.toString(pause));
198
199 // Set process id
200 Long pid = getProcessId();
201 if (pid != null) {
202 packet.setProcessId(pid.toString());
203 }
204
205 JdpBroadcaster bcast = new JdpBroadcaster(address, sourceAddress, port, ttl);
206
207 // Stop discovery service if it's already running
208 stopDiscoveryService();
209
210 controller = new JDPControllerRunner(bcast, packet, pause);
211
212 Thread t = new Thread(null, controller, "JDP broadcaster", 0, false);
213 t.setDaemon(true);
214 t.start();
215 }
216
217 /**
218 * Stop running discovery service,
219 * it's safe to attempt to stop not started service
220 */
221 public static synchronized void stopDiscoveryService() {
222 if ( controller != null ){
223 controller.stop();
224 controller = null;
225 }
226 }
227 }