2 * SPDX-License-Identifier: LGPL-2.1-only
4 * Copyright (C) 2015-2016 EfficiOS Inc.
5 * Copyright (C) 2015-2016 Alexandre Montplaisir <alexmonthy@efficios.com>
6 * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
9 package org
.lttng
.ust
.agent
.client
;
11 import java
.io
.BufferedReader
;
12 import java
.io
.DataInputStream
;
13 import java
.io
.DataOutputStream
;
14 import java
.io
.FileInputStream
;
15 import java
.io
.FileNotFoundException
;
16 import java
.io
.IOException
;
17 import java
.io
.InputStreamReader
;
18 import java
.lang
.management
.ManagementFactory
;
19 import java
.net
.Socket
;
20 import java
.net
.UnknownHostException
;
21 import java
.nio
.ByteBuffer
;
22 import java
.nio
.ByteOrder
;
23 import java
.nio
.charset
.Charset
;
24 import java
.util
.concurrent
.CountDownLatch
;
25 import java
.util
.concurrent
.TimeUnit
;
27 import org
.lttng
.ust
.agent
.utils
.LttngUstAgentLogger
;
30 * Client for agents to connect to a local session daemon, using a TCP socket.
32 * @author David Goulet
34 public class LttngTcpSessiondClient
implements Runnable
{
36 private static final String SESSION_HOST
= "127.0.0.1";
37 private static final String ROOT_PORT_FILE
= "/var/run/lttng/agent.port";
38 private static final String USER_PORT_FILE
= "/.lttng/agent.port";
39 private static final Charset PORT_FILE_ENCODING
= Charset
.forName("UTF-8");
41 private static final int PROTOCOL_MAJOR_VERSION
= 2;
42 private static final int PROTOCOL_MINOR_VERSION
= 0;
44 /** Command header from the session daemon. */
45 private final CountDownLatch registrationLatch
= new CountDownLatch(1);
47 private Socket sessiondSock
;
48 private volatile boolean quit
= false;
50 private DataInputStream inFromSessiond
;
51 private DataOutputStream outToSessiond
;
53 private final ILttngTcpClientListener logAgent
;
54 private final int domainValue
;
55 private final boolean isRoot
;
61 * The listener this client will operate on, typically an LTTng
64 * The integer to send to the session daemon representing the
65 * tracing domain to handle.
67 * True if this client should connect to the root session daemon,
68 * false if it should connect to the user one.
70 public LttngTcpSessiondClient(ILttngTcpClientListener logAgent
, int domainValue
, boolean isRoot
) {
71 this.logAgent
= logAgent
;
72 this.domainValue
= domainValue
;
77 * Wait until this client has successfully established a connection to its
78 * target session daemon.
81 * A timeout in seconds after which this method will return
83 * @return True if the the client actually established the connection, false
84 * if we returned because the timeout has elapsed or the thread was
87 public boolean waitForConnection(int seconds
) {
89 return registrationLatch
.await(seconds
, TimeUnit
.SECONDS
);
90 } catch (InterruptedException e
) {
105 * Connect to the session daemon before anything else.
107 log("Connecting to sessiond");
111 * Register to the session daemon as the Java component of the
114 log("Registering to sessiond");
115 registerToSessiond();
118 * Block on socket receive and wait for command from the
119 * session daemon. This will return if and only if there is a
120 * fatal error or the socket closes.
122 log("Waiting on sessiond commands...");
124 } catch (UnknownHostException uhe
) {
125 uhe
.printStackTrace();
127 * Terminate agent thread.
130 } catch (IOException ioe
) {
132 * I/O exception may have been triggered by a session daemon
133 * closing the socket. Close our own socket and
134 * retry connecting after a delay.
137 if (this.sessiondSock
!= null) {
138 this.sessiondSock
.close();
141 } catch (InterruptedException e
) {
143 * Retry immediately if sleep is interrupted.
145 } catch (IOException closeioe
) {
146 closeioe
.printStackTrace();
148 * Terminate agent thread.
157 * Dispose this client and close any socket connection it may hold.
159 public void close() {
160 log("Closing client");
164 if (this.sessiondSock
!= null) {
165 this.sessiondSock
.close();
167 } catch (IOException e
) {
172 private void connectToSessiond() throws IOException
{
173 int rootPort
= getPortFromFile(ROOT_PORT_FILE
);
174 int userPort
= getPortFromFile(getHomePath() + USER_PORT_FILE
);
177 * Check for the edge case of both files existing but pointing to the
178 * same port. In this case, let the root client handle it.
180 if ((rootPort
!= 0) && (rootPort
== userPort
) && (!isRoot
)) {
181 log("User and root config files both point to port " + rootPort
+
182 ". Letting the root client handle it.");
183 throw new IOException();
186 int portToUse
= (isRoot ? rootPort
: userPort
);
188 if (portToUse
== 0) {
189 /* No session daemon available. Stop and retry later. */
190 throw new IOException();
193 this.sessiondSock
= new Socket(SESSION_HOST
, portToUse
);
194 this.inFromSessiond
= new DataInputStream(sessiondSock
.getInputStream());
195 this.outToSessiond
= new DataOutputStream(sessiondSock
.getOutputStream());
198 private static String
getHomePath() {
200 * The environment variable LTTNG_HOME overrides HOME if
203 String homePath
= System
.getenv("LTTNG_HOME");
205 if (homePath
== null) {
206 homePath
= System
.getProperty("user.home");
212 * Read port number from file created by the session daemon.
214 * @return port value if found else 0.
216 private static int getPortFromFile(String path
) throws IOException
{
217 BufferedReader br
= null;
220 br
= new BufferedReader(new InputStreamReader(new FileInputStream(path
), PORT_FILE_ENCODING
));
221 String line
= br
.readLine();
223 /* File exists but is empty. */
227 int port
= Integer
.parseInt(line
, 10);
228 if (port
< 0 || port
> 65535) {
229 /* Invalid value. Ignore. */
234 } catch (NumberFormatException e
) {
235 /* File contained something that was not a number. */
237 } catch (FileNotFoundException e
) {
238 /* No port available. */
247 private void registerToSessiond() throws IOException
{
248 byte data
[] = new byte[16];
249 ByteBuffer buf
= ByteBuffer
.wrap(data
);
250 String pid
= ManagementFactory
.getRuntimeMXBean().getName().split("@")[0];
252 buf
.putInt(domainValue
);
253 buf
.putInt(Integer
.parseInt(pid
));
254 buf
.putInt(PROTOCOL_MAJOR_VERSION
);
255 buf
.putInt(PROTOCOL_MINOR_VERSION
);
256 this.outToSessiond
.write(data
, 0, data
.length
);
257 this.outToSessiond
.flush();
261 * Handle session command from the session daemon.
263 private void handleSessiondCmd() throws IOException
{
264 /* Data read from the socket */
265 byte inputData
[] = null;
266 /* Reply data written to the socket, sent to the sessiond */
267 LttngAgentResponse response
;
270 /* Get header from session daemon. */
271 SessiondCommandHeader cmdHeader
= recvHeader();
273 if (cmdHeader
.getDataSize() > 0) {
274 inputData
= recvPayload(cmdHeader
);
277 switch (cmdHeader
.getCommandType()) {
281 * Countdown the registration latch, meaning registration is
282 * done and we can proceed to continue tracing.
284 registrationLatch
.countDown();
286 * We don't send any reply to the registration done command.
287 * This just marks the end of the initial session setup.
289 log("Registration done");
294 SessiondCommand listLoggerCmd
= new SessiondListLoggersCommand();
295 response
= listLoggerCmd
.execute(logAgent
);
296 log("Received list loggers command");
299 case CMD_EVENT_ENABLE
:
301 if (inputData
== null) {
302 /* Invalid command */
303 response
= LttngAgentResponse
.FAILURE_RESPONSE
;
306 SessiondCommand enableEventCmd
= new SessiondEnableEventCommand(inputData
);
307 response
= enableEventCmd
.execute(logAgent
);
308 log("Received enable event command: " + enableEventCmd
.toString());
311 case CMD_EVENT_DISABLE
:
313 if (inputData
== null) {
314 /* Invalid command */
315 response
= LttngAgentResponse
.FAILURE_RESPONSE
;
318 SessiondCommand disableEventCmd
= new SessiondDisableEventCommand(inputData
);
319 response
= disableEventCmd
.execute(logAgent
);
320 log("Received disable event command: " + disableEventCmd
.toString());
323 case CMD_APP_CTX_ENABLE
:
325 if (inputData
== null) {
326 /* This commands expects a payload, invalid command */
327 response
= LttngAgentResponse
.FAILURE_RESPONSE
;
330 SessiondCommand enableAppCtxCmd
= new SessiondEnableAppContextCommand(inputData
);
331 response
= enableAppCtxCmd
.execute(logAgent
);
332 log("Received enable app-context command");
335 case CMD_APP_CTX_DISABLE
:
337 if (inputData
== null) {
338 /* This commands expects a payload, invalid command */
339 response
= LttngAgentResponse
.FAILURE_RESPONSE
;
342 SessiondCommand disableAppCtxCmd
= new SessiondDisableAppContextCommand(inputData
);
343 response
= disableAppCtxCmd
.execute(logAgent
);
344 log("Received disable app-context command");
349 /* Unknown command, send empty reply */
351 log("Received unknown command, ignoring");
356 /* Send response to the session daemon. */
358 if (response
== null) {
359 responseData
= new byte[4];
360 ByteBuffer buf
= ByteBuffer
.wrap(responseData
);
361 buf
.order(ByteOrder
.BIG_ENDIAN
);
363 log("Sending response: " + response
.toString());
364 responseData
= response
.getBytes();
366 this.outToSessiond
.write(responseData
, 0, responseData
.length
);
367 this.outToSessiond
.flush();
372 * Receive header data from the session daemon using the LTTng command
373 * static buffer of the right size.
375 private SessiondCommandHeader
recvHeader() throws IOException
{
376 byte data
[] = new byte[SessiondCommandHeader
.HEADER_SIZE
];
377 int bytesLeft
= data
.length
;
380 while (bytesLeft
> 0) {
381 int bytesRead
= this.inFromSessiond
.read(data
, bytesOffset
, bytesLeft
);
384 throw new IOException();
386 bytesLeft
-= bytesRead
;
387 bytesOffset
+= bytesRead
;
389 return new SessiondCommandHeader(data
);
393 * Receive payload from the session daemon. This MUST be done after a
394 * recvHeader() so the header value of a command are known.
396 * The caller SHOULD use isPayload() before which returns true if a payload
397 * is expected after the header.
399 private byte[] recvPayload(SessiondCommandHeader headerCmd
) throws IOException
{
400 byte payload
[] = new byte[(int) headerCmd
.getDataSize()];
401 int bytesLeft
= payload
.length
;
404 /* Failsafe check so we don't waste our time reading 0 bytes. */
405 if (bytesLeft
== 0) {
409 while (bytesLeft
> 0) {
410 int bytesRead
= inFromSessiond
.read(payload
, bytesOffset
, bytesLeft
);
413 throw new IOException();
415 bytesLeft
-= bytesRead
;
416 bytesOffset
+= bytesRead
;
422 * Wrapper for this class's logging, adds the connection's characteristics
423 * to help differentiate between multiple TCP clients.
425 private void log(String message
) {
426 LttngUstAgentLogger
.log(getClass(),
427 "(root=" + isRoot
+ ", domain=" + domainValue
+ ") " + message
);