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_UST_HOME overrides LTTNG_HOME
202 * The environment variable LTTNG_HOME overrides HOME if
205 String lttngUstHomePath
= System
.getenv("LTTNG_UST_HOME");
206 String lttngHomePath
= System
.getenv("LTTNG_HOME");
208 if (lttngUstHomePath
!= null) {
210 * LTTNG_UST_HOME has priority over LTTNG_HOME and user
213 return lttngUstHomePath
;
216 if (lttngHomePath
!= null) {
217 /* LTTNG_HOME has priority over user home directory. */
218 return lttngHomePath
;
221 /* Default to the user home directory. */
222 return System
.getProperty("user.home");
226 * Read port number from file created by the session daemon.
228 * @return port value if found else 0.
230 private static int getPortFromFile(String path
) throws IOException
{
231 BufferedReader br
= null;
234 br
= new BufferedReader(new InputStreamReader(new FileInputStream(path
), PORT_FILE_ENCODING
));
235 String line
= br
.readLine();
237 /* File exists but is empty. */
241 int port
= Integer
.parseInt(line
, 10);
242 if (port
< 0 || port
> 65535) {
243 /* Invalid value. Ignore. */
248 } catch (NumberFormatException e
) {
249 /* File contained something that was not a number. */
251 } catch (FileNotFoundException e
) {
252 /* No port available. */
261 private void registerToSessiond() throws IOException
{
262 byte data
[] = new byte[16];
263 ByteBuffer buf
= ByteBuffer
.wrap(data
);
264 String pid
= ManagementFactory
.getRuntimeMXBean().getName().split("@")[0];
266 buf
.putInt(domainValue
);
267 buf
.putInt(Integer
.parseInt(pid
));
268 buf
.putInt(PROTOCOL_MAJOR_VERSION
);
269 buf
.putInt(PROTOCOL_MINOR_VERSION
);
270 this.outToSessiond
.write(data
, 0, data
.length
);
271 this.outToSessiond
.flush();
275 * Handle session command from the session daemon.
277 private void handleSessiondCmd() throws IOException
{
278 /* Data read from the socket */
279 byte inputData
[] = null;
280 /* Reply data written to the socket, sent to the sessiond */
281 LttngAgentResponse response
;
284 /* Get header from session daemon. */
285 SessiondCommandHeader cmdHeader
= recvHeader();
287 if (cmdHeader
.getDataSize() > 0) {
288 inputData
= recvPayload(cmdHeader
);
291 switch (cmdHeader
.getCommandType()) {
295 * Countdown the registration latch, meaning registration is
296 * done and we can proceed to continue tracing.
298 registrationLatch
.countDown();
300 * We don't send any reply to the registration done command.
301 * This just marks the end of the initial session setup.
303 log("Registration done");
308 SessiondCommand listLoggerCmd
= new SessiondListLoggersCommand();
309 response
= listLoggerCmd
.execute(logAgent
);
310 log("Received list loggers command");
313 case CMD_EVENT_ENABLE
:
315 if (inputData
== null) {
316 /* Invalid command */
317 response
= LttngAgentResponse
.FAILURE_RESPONSE
;
320 SessiondCommand enableEventCmd
= new SessiondEnableEventCommand(inputData
);
321 response
= enableEventCmd
.execute(logAgent
);
322 log("Received enable event command: " + enableEventCmd
.toString());
325 case CMD_EVENT_DISABLE
:
327 if (inputData
== null) {
328 /* Invalid command */
329 response
= LttngAgentResponse
.FAILURE_RESPONSE
;
332 SessiondCommand disableEventCmd
= new SessiondDisableEventCommand(inputData
);
333 response
= disableEventCmd
.execute(logAgent
);
334 log("Received disable event command: " + disableEventCmd
.toString());
337 case CMD_APP_CTX_ENABLE
:
339 if (inputData
== null) {
340 /* This commands expects a payload, invalid command */
341 response
= LttngAgentResponse
.FAILURE_RESPONSE
;
344 SessiondCommand enableAppCtxCmd
= new SessiondEnableAppContextCommand(inputData
);
345 response
= enableAppCtxCmd
.execute(logAgent
);
346 log("Received enable app-context command");
349 case CMD_APP_CTX_DISABLE
:
351 if (inputData
== null) {
352 /* This commands expects a payload, invalid command */
353 response
= LttngAgentResponse
.FAILURE_RESPONSE
;
356 SessiondCommand disableAppCtxCmd
= new SessiondDisableAppContextCommand(inputData
);
357 response
= disableAppCtxCmd
.execute(logAgent
);
358 log("Received disable app-context command");
363 /* Unknown command, send empty reply */
365 log("Received unknown command, ignoring");
370 /* Send response to the session daemon. */
372 if (response
== null) {
373 responseData
= new byte[4];
374 ByteBuffer buf
= ByteBuffer
.wrap(responseData
);
375 buf
.order(ByteOrder
.BIG_ENDIAN
);
377 log("Sending response: " + response
.toString());
378 responseData
= response
.getBytes();
380 this.outToSessiond
.write(responseData
, 0, responseData
.length
);
381 this.outToSessiond
.flush();
386 * Receive header data from the session daemon using the LTTng command
387 * static buffer of the right size.
389 private SessiondCommandHeader
recvHeader() throws IOException
{
390 byte data
[] = new byte[SessiondCommandHeader
.HEADER_SIZE
];
391 int bytesLeft
= data
.length
;
394 while (bytesLeft
> 0) {
395 int bytesRead
= this.inFromSessiond
.read(data
, bytesOffset
, bytesLeft
);
398 throw new IOException();
400 bytesLeft
-= bytesRead
;
401 bytesOffset
+= bytesRead
;
403 return new SessiondCommandHeader(data
);
407 * Receive payload from the session daemon. This MUST be done after a
408 * recvHeader() so the header value of a command are known.
410 * The caller SHOULD use isPayload() before which returns true if a payload
411 * is expected after the header.
413 private byte[] recvPayload(SessiondCommandHeader headerCmd
) throws IOException
{
414 byte payload
[] = new byte[(int) headerCmd
.getDataSize()];
415 int bytesLeft
= payload
.length
;
418 /* Failsafe check so we don't waste our time reading 0 bytes. */
419 if (bytesLeft
== 0) {
423 while (bytesLeft
> 0) {
424 int bytesRead
= inFromSessiond
.read(payload
, bytesOffset
, bytesLeft
);
427 throw new IOException();
429 bytesLeft
-= bytesRead
;
430 bytesOffset
+= bytesRead
;
436 * Wrapper for this class's logging, adds the connection's characteristics
437 * to help differentiate between multiple TCP clients.
439 private void log(String message
) {
440 LttngUstAgentLogger
.log(getClass(),
441 "(root=" + isRoot
+ ", domain=" + domainValue
+ ") " + message
);