liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/LTTngTCPSessiondClient.java

   1 /*
   2  * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
   3  *
   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.
   7  *
   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
  11  * for more details.
  12  *
  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
  16  */
  17
  18 package org.lttng.ust.agent;
  19
  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.Semaphore;
  32
  33 class LTTngTCPSessiondClient implements Runnable {
  34
  35         private static final String SESSION_HOST = "127.0.0.1";
  36         private static final String ROOT_PORT_FILE = "/var/run/lttng/agent.port";
  37         private static final String USER_PORT_FILE = "/.lttng/agent.port";
  38
  39         private static Integer protocolMajorVersion = 1;
  40         private static Integer protocolMinorVersion = 0;
  41
  42         /* Command header from the session deamon. */
  43         private LTTngSessiondCmd2_6.sessiond_hdr headerCmd =
  44                 new LTTngSessiondCmd2_6.sessiond_hdr();
  45
  46         private Socket sessiondSock;
  47         private volatile boolean quit = false;
  48
  49         private DataInputStream inFromSessiond;
  50         private DataOutputStream outToSessiond;
  51
  52         private LogFramework log;
  53
  54         private Semaphore registerSem;
  55
  56
  57         private LTTngAgent.Domain agentDomain;
  58
  59         /* Indicate if we've already released the semaphore. */
  60         private boolean semPosted = false;
  61
  62         public LTTngTCPSessiondClient(LTTngAgent.Domain domain, LogFramework log, Semaphore sem) {
  63                 this.agentDomain = domain;
  64                 this.log = log;
  65                 this.registerSem = sem;
  66         }
  67
  68         /*
  69          * Try to release the registerSem if it's not already done.
  70          */
  71         private void tryReleaseSem() {
  72                 /* Release semaphore so we unblock the agent. */
  73                 if (!this.semPosted) {
  74                         this.registerSem.release();
  75                         this.semPosted = true;
  76                 }
  77         }
  78
  79         @Override
  80         public void run() {
  81                 for (;;) {
  82                         if (this.quit) {
  83                                 break;
  84                         }
  85
  86                         /* Cleanup Agent state before trying to connect or reconnect. */
  87                         this.log.reset();
  88
  89                         try {
  90
  91                                 /*
  92                                  * Connect to the session daemon before anything else.
  93                                  */
  94                                 connectToSessiond();
  95
  96                                 /*
  97                                  * Register to the session daemon as the Java component of the
  98                                  * UST application.
  99                                  */
 100                                 registerToSessiond();
 101
 102                                 /*
 103                                  * Block on socket receive and wait for command from the
 104                                  * session daemon. This will return if and only if there is a
 105                                  * fatal error or the socket closes.
 106                                  */
 107                                 handleSessiondCmd();
 108                         } catch (UnknownHostException uhe) {
 109                                 tryReleaseSem();
 110                                 System.out.println(uhe);
 111                         } catch (IOException ioe) {
 112                                 tryReleaseSem();
 113                                 try {
 114                                         Thread.sleep(3000);
 115                                 } catch (InterruptedException e) {
 116                                         e.printStackTrace();
 117                                 }
 118                         } catch (Exception e) {
 119                                 tryReleaseSem();
 120                                 e.printStackTrace();
 121                         }
 122                 }
 123         }
 124
 125         public void destroy() {
 126                 this.quit = true;
 127
 128                 try {
 129                         if (this.sessiondSock != null) {
 130                                 this.sessiondSock.close();
 131                         }
 132                 } catch (Exception e) {
 133                         e.printStackTrace();
 134                 }
 135         }
 136
 137         /*
 138          * Receive header data from the session daemon using the LTTng command
 139          * static buffer of the right size.
 140          */
 141         private void recvHeader() throws Exception {
 142                 byte data[] = new byte[LTTngSessiondCmd2_6.sessiond_hdr.SIZE];
 143
 144                 int readLen = this.inFromSessiond.read(data, 0, data.length);
 145                 if (readLen != data.length) {
 146                         throw new IOException();
 147                 }
 148                 this.headerCmd.populate(data);
 149         }
 150
 151         /*
 152          * Receive payload from the session daemon. This MUST be done after a
 153          * recvHeader() so the header value of a command are known.
 154          *
 155          * The caller SHOULD use isPayload() before which returns true if a payload
 156          * is expected after the header.
 157          */
 158         private byte[] recvPayload() throws Exception {
 159                 byte payload[] = new byte[(int) this.headerCmd.dataSize];
 160
 161                 /* Failsafe check so we don't waste our time reading 0 bytes. */
 162                 if (payload.length == 0) {
 163                         return null;
 164                 }
 165
 166                 this.inFromSessiond.read(payload, 0, payload.length);
 167                 return payload;
 168         }
 169
 170         /*
 171          * Handle session command from the session daemon.
 172          */
 173         private void handleSessiondCmd() throws Exception {
 174                 byte data[] = null;
 175
 176                 while (true) {
 177                         /* Get header from session daemon. */
 178                         recvHeader();
 179
 180                         if (headerCmd.dataSize > 0) {
 181                                 data = recvPayload();
 182                         }
 183
 184                         switch (headerCmd.cmd) {
 185                                 case CMD_REG_DONE:
 186                                 {
 187                                         /*
 188                                          * Release semaphore so meaning registration is done and we
 189                                          * can proceed to continue tracing.
 190                                          */
 191                                         tryReleaseSem();
 192                                         /*
 193                                          * We don't send any reply to the registration done command.
 194                                          * This just marks the end of the initial session setup.
 195                                          */
 196                                         continue;
 197                                 }
 198                                 case CMD_LIST:
 199                                 {
 200                                         LTTngSessiondCmd2_6.sessiond_list_logger listLoggerCmd =
 201                                                 new LTTngSessiondCmd2_6.sessiond_list_logger();
 202                                         listLoggerCmd.execute(this.log);
 203                                         data = listLoggerCmd.getBytes();
 204                                         break;
 205                                 }
 206                                 case CMD_ENABLE:
 207                                 {
 208                                         LTTngSessiondCmd2_6.sessiond_enable_handler enableCmd =
 209                                                 new LTTngSessiondCmd2_6.sessiond_enable_handler();
 210                                         if (data == null) {
 211                                                 enableCmd.code = LTTngSessiondCmd2_6.lttng_agent_ret_code.CODE_INVALID_CMD;
 212                                                 break;
 213                                         }
 214                                         enableCmd.populate(data);
 215                                         enableCmd.execute(this.log);
 216                                         data = enableCmd.getBytes();
 217                                         break;
 218                                 }
 219                                 case CMD_DISABLE:
 220                                 {
 221                                         LTTngSessiondCmd2_6.sessiond_disable_handler disableCmd =
 222                                                 new LTTngSessiondCmd2_6.sessiond_disable_handler();
 223                                         if (data == null) {
 224                                                 disableCmd.code = LTTngSessiondCmd2_6.lttng_agent_ret_code.CODE_INVALID_CMD;
 225                                                 break;
 226                                         }
 227                                         disableCmd.populate(data);
 228                                         disableCmd.execute(this.log);
 229                                         data = disableCmd.getBytes();
 230                                         break;
 231                                 }
 232                                 default:
 233                                 {
 234                                         data = new byte[4];
 235                                         ByteBuffer buf = ByteBuffer.wrap(data);
 236                                         buf.order(ByteOrder.BIG_ENDIAN);
 237                                         break;
 238                                 }
 239                         }
 240
 241                         /* Send payload to session daemon. */
 242                         this.outToSessiond.write(data, 0, data.length);
 243                         this.outToSessiond.flush();
 244                 }
 245         }
 246
 247         private static String getHomePath() {
 248                 return System.getProperty("user.home");
 249         }
 250
 251         /**
 252          * Read port number from file created by the session daemon.
 253          *
 254          * @return port value if found else 0.
 255          */
 256         private static int getPortFromFile(String path) throws IOException {
 257                 int port;
 258                 BufferedReader br;
 259
 260                 try {
 261                         br = new BufferedReader(new FileReader(path));
 262                         String line = br.readLine();
 263                         port = Integer.parseInt(line, 10);
 264                         if (port < 0 || port > 65535) {
 265                                 /* Invalid value. Ignore. */
 266                                 port = 0;
 267                         }
 268                         br.close();
 269                 } catch (FileNotFoundException e) {
 270                         /* No port available. */
 271                         port = 0;
 272                 }
 273
 274                 return port;
 275         }
 276
 277         private void connectToSessiond() throws Exception {
 278                 int port;
 279
 280                 if (this.log.isRoot()) {
 281                         port = getPortFromFile(ROOT_PORT_FILE);
 282                         if (port == 0) {
 283                                 /* No session daemon available. Stop and retry later. */
 284                                 throw new IOException();
 285                         }
 286                 } else {
 287                         port = getPortFromFile(getHomePath() + USER_PORT_FILE);
 288                         if (port == 0) {
 289                                 /* No session daemon available. Stop and retry later. */
 290                                 throw new IOException();
 291                         }
 292                 }
 293
 294                 this.sessiondSock = new Socket(SESSION_HOST, port);
 295                 this.inFromSessiond = new DataInputStream(sessiondSock.getInputStream());
 296                 this.outToSessiond = new DataOutputStream(sessiondSock.getOutputStream());
 297         }
 298
 299         private void registerToSessiond() throws Exception {
 300                 byte data[] = new byte[16];
 301                 ByteBuffer buf = ByteBuffer.wrap(data);
 302                 String pid = ManagementFactory.getRuntimeMXBean().getName().split("@")[0];
 303
 304                 buf.putInt(this.agentDomain.value());
 305                 buf.putInt(Integer.parseInt(pid));
 306                 buf.putInt(protocolMajorVersion);
 307                 buf.putInt(protocolMinorVersion);
 308                 this.outToSessiond.write(data, 0, data.length);
 309                 this.outToSessiond.flush();
 310         }
 311 }