2 * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
4 * This library is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU Lesser General Public License, version 2.1 only,
6 * as published by the Free Software Foundation.
8 * This library is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
13 * You should have received a copy of the GNU Lesser General Public License
14 * along with this library; if not, write to the Free Software Foundation,
15 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 package org
.lttng
.ust
.agent
.client
;
20 import java
.io
.BufferedReader
;
21 import java
.io
.DataInputStream
;
22 import java
.io
.DataOutputStream
;
23 import java
.io
.FileNotFoundException
;
24 import java
.io
.FileReader
;
25 import java
.io
.IOException
;
26 import java
.lang
.management
.ManagementFactory
;
27 import java
.net
.Socket
;
28 import java
.net
.UnknownHostException
;
29 import java
.nio
.ByteBuffer
;
30 import java
.nio
.ByteOrder
;
31 import java
.util
.concurrent
.CountDownLatch
;
32 import java
.util
.concurrent
.TimeUnit
;
34 import org
.lttng
.ust
.agent
.AbstractLttngAgent
;
37 * Client for agents to connect to a local session daemon, using a TCP socket.
39 * @author David Goulet
41 public class LttngTcpSessiondClient
implements Runnable
{
43 private static final String SESSION_HOST
= "127.0.0.1";
44 private static final String ROOT_PORT_FILE
= "/var/run/lttng/agent.port";
45 private static final String USER_PORT_FILE
= "/.lttng/agent.port";
47 private static int protocolMajorVersion
= 1;
48 private static int protocolMinorVersion
= 0;
50 /** Command header from the session deamon. */
51 private final CountDownLatch registrationLatch
= new CountDownLatch(1);
53 private Socket sessiondSock
;
54 private volatile boolean quit
= false;
56 private DataInputStream inFromSessiond
;
57 private DataOutputStream outToSessiond
;
59 private final AbstractLttngAgent
<?
> logAgent
;
60 private final boolean isRoot
;
67 * The logging agent this client will operate on.
69 * True if this client should connect to the root session daemon,
70 * false if it should connect to the user one.
72 public LttngTcpSessiondClient(AbstractLttngAgent
<?
> logAgent
, boolean isRoot
) {
73 this.logAgent
= logAgent
;
78 * Wait until this client has successfully established a connection to its
79 * target session daemon.
82 * A timeout in seconds after which this method will return
84 * @return True if the the client actually established the connection, false
85 * if we returned because the timeout has elapsed or the thread was
88 public boolean waitForConnection(int seconds
) {
90 return registrationLatch
.await(seconds
, TimeUnit
.SECONDS
);
91 } catch (InterruptedException e
) {
106 * Connect to the session daemon before anything else.
111 * Register to the session daemon as the Java component of the
114 registerToSessiond();
117 * Block on socket receive and wait for command from the
118 * session daemon. This will return if and only if there is a
119 * fatal error or the socket closes.
122 } catch (UnknownHostException uhe
) {
123 uhe
.printStackTrace();
124 } catch (IOException ioe
) {
127 } catch (InterruptedException e
) {
135 * Dispose this client and close any socket connection it may hold.
137 public void close() {
141 if (this.sessiondSock
!= null) {
142 this.sessiondSock
.close();
144 } catch (IOException e
) {
149 private void connectToSessiond() throws IOException
{
153 port
= getPortFromFile(ROOT_PORT_FILE
);
155 /* No session daemon available. Stop and retry later. */
156 throw new IOException();
159 port
= getPortFromFile(getHomePath() + USER_PORT_FILE
);
161 /* No session daemon available. Stop and retry later. */
162 throw new IOException();
166 this.sessiondSock
= new Socket(SESSION_HOST
, port
);
167 this.inFromSessiond
= new DataInputStream(sessiondSock
.getInputStream());
168 this.outToSessiond
= new DataOutputStream(sessiondSock
.getOutputStream());
171 private static String
getHomePath() {
172 return System
.getProperty("user.home");
176 * Read port number from file created by the session daemon.
178 * @return port value if found else 0.
180 private static int getPortFromFile(String path
) throws IOException
{
182 BufferedReader br
= null;
185 br
= new BufferedReader(new FileReader(path
));
186 String line
= br
.readLine();
187 port
= Integer
.parseInt(line
, 10);
188 if (port
< 0 || port
> 65535) {
189 /* Invalid value. Ignore. */
192 } catch (FileNotFoundException e
) {
193 /* No port available. */
204 private void registerToSessiond() throws IOException
{
205 byte data
[] = new byte[16];
206 ByteBuffer buf
= ByteBuffer
.wrap(data
);
207 String pid
= ManagementFactory
.getRuntimeMXBean().getName().split("@")[0];
209 buf
.putInt(logAgent
.getDomain().value());
210 buf
.putInt(Integer
.parseInt(pid
));
211 buf
.putInt(protocolMajorVersion
);
212 buf
.putInt(protocolMinorVersion
);
213 this.outToSessiond
.write(data
, 0, data
.length
);
214 this.outToSessiond
.flush();
218 * Handle session command from the session daemon.
220 private void handleSessiondCmd() throws IOException
{
221 /* Data read from the socket */
222 byte inputData
[] = null;
223 /* Reply data written to the socket, sent to the sessiond */
224 byte responseData
[] = null;
227 /* Get header from session daemon. */
228 SessiondCommandHeader cmdHeader
= recvHeader();
230 if (cmdHeader
.getDataSize() > 0) {
231 inputData
= recvPayload(cmdHeader
);
234 switch (cmdHeader
.getCommandType()) {
238 * Countdown the registration latch, meaning registration is
239 * done and we can proceed to continue tracing.
241 registrationLatch
.countDown();
243 * We don't send any reply to the registration done command.
244 * This just marks the end of the initial session setup.
250 ISessiondCommand listLoggerCmd
= new SessiondListLoggersCommand();
251 ILttngAgentResponse response
= listLoggerCmd
.execute(logAgent
);
252 responseData
= response
.getBytes();
257 if (inputData
== null) {
258 /* Invalid command */
259 responseData
= ILttngAgentResponse
.FAILURE_RESPONSE
.getBytes();
262 ISessiondCommand enableCmd
= new SessiondEnableEventCommand(inputData
);
263 ILttngAgentResponse response
= enableCmd
.execute(logAgent
);
264 responseData
= response
.getBytes();
269 if (inputData
== null) {
270 /* Invalid command */
271 responseData
= ILttngAgentResponse
.FAILURE_RESPONSE
.getBytes();
274 ISessiondCommand disableCmd
= new SessiondDisableEventCommand(inputData
);
275 ILttngAgentResponse response
= disableCmd
.execute(logAgent
);
276 responseData
= response
.getBytes();
281 /* Unknown command, send empty reply */
282 responseData
= new byte[4];
283 ByteBuffer buf
= ByteBuffer
.wrap(responseData
);
284 buf
.order(ByteOrder
.BIG_ENDIAN
);
289 /* Send response to the session daemon. */
290 this.outToSessiond
.write(responseData
, 0, responseData
.length
);
291 this.outToSessiond
.flush();
296 * Receive header data from the session daemon using the LTTng command
297 * static buffer of the right size.
299 private SessiondCommandHeader
recvHeader() throws IOException
{
300 byte data
[] = new byte[SessiondCommandHeader
.HEADER_SIZE
];
302 int readLen
= this.inFromSessiond
.read(data
, 0, data
.length
);
303 if (readLen
!= data
.length
) {
304 throw new IOException();
306 return new SessiondCommandHeader(data
);
310 * Receive payload from the session daemon. This MUST be done after a
311 * recvHeader() so the header value of a command are known.
313 * The caller SHOULD use isPayload() before which returns true if a payload
314 * is expected after the header.
316 private byte[] recvPayload(SessiondCommandHeader headerCmd
) throws IOException
{
317 byte payload
[] = new byte[(int) headerCmd
.getDataSize()];
319 /* Failsafe check so we don't waste our time reading 0 bytes. */
320 if (payload
.length
== 0) {
324 this.inFromSessiond
.read(payload
, 0, payload
.length
);