liblttng-ust-jul/org/lttng/ust/jul/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.jul;
  19
  20 import java.util.concurrent.Semaphore;
  21 import java.nio.ByteBuffer;
  22 import java.nio.ByteOrder;
  23 import java.lang.Integer;
  24 import java.io.IOException;
  25 import java.io.BufferedOutputStream;
  26 import java.io.BufferedReader;
  27 import java.io.ByteArrayOutputStream;
  28 import java.io.DataOutputStream;
  29 import java.io.DataInputStream;
  30 import java.io.FileReader;
  31 import java.io.FileNotFoundException;
  32 import java.net.*;
  33 import java.lang.management.ManagementFactory;
  34 import java.util.logging.Logger;
  35
  36 class USTRegisterMsg {
  37         public static int pid;
  38 }
  39
  40 public class LTTngTCPSessiondClient {
  41         /* Command header from the session deamon. */
  42         private LTTngSessiondCmd2_4.sessiond_hdr headerCmd =
  43                 new LTTngSessiondCmd2_4.sessiond_hdr();
  44
  45         private final String sessiondHost;
  46         private Socket sessiondSock;
  47         private boolean quit = false;
  48
  49         private DataInputStream inFromSessiond;
  50         private DataOutputStream outToSessiond;
  51
  52         private LTTngLogHandler handler;
  53
  54         private Semaphore registerSem;
  55
  56         private static final String rootPortFile = "/var/run/lttng/agent.port";
  57         private static final String userPortFile = "/.lttng/agent.port";
  58         /*
  59          * This is taken from the lttng/domain.h file which is mapped to
  60          * LTTNG_DOMAIN_JUL value for this agent.
  61          */
  62         private static final int agent_domain = 3;
  63
  64         /* Indicate if we've already release the semaphore. */
  65         private boolean sem_posted = false;
  66
  67         public LTTngTCPSessiondClient(String host, Semaphore sem) {
  68                 this.sessiondHost = host;
  69                 this.registerSem = sem;
  70         }
  71
  72         /*
  73          * Try to release the registerSem if it's not already done.
  74          */
  75         private void tryReleaseSem()
  76         {
  77                 /* Release semaphore so we unblock the agent. */
  78                 if (!this.sem_posted) {
  79                         this.registerSem.release();
  80                         this.sem_posted = true;
  81                 }
  82         }
  83
  84         /*
  85          * Cleanup Agent state.
  86          */
  87         private void cleanupState() {
  88                 if (this.handler != null) {
  89                         this.handler.clear();
  90                 }
  91         }
  92
  93         public void init(LTTngLogHandler handler) throws InterruptedException {
  94                 this.handler = handler;
  95
  96                 for (;;) {
  97                         if (this.quit) {
  98                                 break;
  99                         }
 100
 101                         /* Cleanup Agent state before trying to connect or reconnect. */
 102                         cleanupState();
 103
 104                         try {
 105
 106                                 /*
 107                                  * Connect to the session daemon before anything else.
 108                                  */
 109                                 connectToSessiond();
 110
 111                                 /*
 112                                  * Register to the session daemon as the Java component of the
 113                                  * UST application.
 114                                  */
 115                                 registerToSessiond();
 116
 117                                 /*
 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.
 121                                  */
 122                                 handleSessiondCmd();
 123                         } catch (UnknownHostException uhe) {
 124                                 tryReleaseSem();
 125                                 System.out.println(uhe);
 126                         } catch (IOException ioe) {
 127                                 tryReleaseSem();
 128                                 Thread.sleep(3000);
 129                         } catch (Exception e) {
 130                                 tryReleaseSem();
 131                                 e.printStackTrace();
 132                         }
 133                 }
 134         }
 135
 136         public void destroy() {
 137                 this.quit = true;
 138
 139                 try {
 140                         if (this.sessiondSock != null) {
 141                                 this.sessiondSock.close();
 142                         }
 143                 } catch (Exception e) {
 144                         e.printStackTrace();
 145                 }
 146         }
 147
 148         /*
 149          * Receive header data from the session daemon using the LTTng command
 150          * static buffer of the right size.
 151          */
 152         private void recvHeader() throws Exception {
 153                 int read_len;
 154                 byte data[] = new byte[this.headerCmd.SIZE];
 155
 156                 read_len = this.inFromSessiond.read(data, 0, data.length);
 157                 if (read_len != data.length) {
 158                         throw new IOException();
 159                 }
 160                 this.headerCmd.populate(data);
 161         }
 162
 163         /*
 164          * Receive payload from the session daemon. This MUST be done after a
 165          * recvHeader() so the header value of a command are known.
 166          *
 167          * The caller SHOULD use isPayload() before which returns true if a payload
 168          * is expected after the header.
 169          */
 170         private byte[] recvPayload() throws Exception {
 171                 byte payload[] = new byte[(int) this.headerCmd.data_size];
 172
 173                 /* Failsafe check so we don't waste our time reading 0 bytes. */
 174                 if (payload.length == 0) {
 175                         return null;
 176                 }
 177
 178                 this.inFromSessiond.read(payload, 0, payload.length);
 179                 return payload;
 180         }
 181
 182         /*
 183          * Handle session command from the session daemon.
 184          */
 185         private void handleSessiondCmd() throws Exception {
 186                 int ret_code;
 187                 byte data[] = null;
 188
 189                 while (true) {
 190                         /* Get header from session daemon. */
 191                         recvHeader();
 192
 193                         if (headerCmd.data_size > 0) {
 194                                 data = recvPayload();
 195                         }
 196
 197                         switch (headerCmd.cmd) {
 198                                 case CMD_REG_DONE:
 199                                 {
 200                                         /*
 201                                          * Release semaphore so meaning registration is done and we
 202                                          * can proceed to continue tracing.
 203                                          */
 204                                         tryReleaseSem();
 205                                         /*
 206                                          * We don't send any reply to the registration done command.
 207                                          * This just marks the end of the initial session setup.
 208                                          */
 209                                         continue;
 210                                 }
 211                                 case CMD_LIST:
 212                                 {
 213                                         LTTngSessiondCmd2_4.sessiond_list_logger listLoggerCmd =
 214                                                 new LTTngSessiondCmd2_4.sessiond_list_logger();
 215                                         listLoggerCmd.execute(this.handler);
 216                                         data = listLoggerCmd.getBytes();
 217                                         break;
 218                                 }
 219                                 case CMD_ENABLE:
 220                                 {
 221                                         LTTngEvent event;
 222                                         LTTngSessiondCmd2_4.sessiond_enable_handler enableCmd =
 223                                                 new LTTngSessiondCmd2_4.sessiond_enable_handler();
 224                                         if (data == null) {
 225                                                 enableCmd.code = LTTngSessiondCmd2_4.lttng_jul_ret_code.CODE_INVALID_CMD;
 226                                                 break;
 227                                         }
 228                                         enableCmd.populate(data);
 229                                         enableCmd.execute(this.handler);
 230                                         data = enableCmd.getBytes();
 231                                         break;
 232                                 }
 233                                 case CMD_DISABLE:
 234                                 {
 235                                         LTTngSessiondCmd2_4.sessiond_disable_handler disableCmd =
 236                                                 new LTTngSessiondCmd2_4.sessiond_disable_handler();
 237                                         if (data == null) {
 238                                                 disableCmd.code = LTTngSessiondCmd2_4.lttng_jul_ret_code.CODE_INVALID_CMD;
 239                                                 break;
 240                                         }
 241                                         disableCmd.populate(data);
 242                                         disableCmd.execute(this.handler);
 243                                         data = disableCmd.getBytes();
 244                                         break;
 245                                 }
 246                                 default:
 247                                 {
 248                                         data = new byte[4];
 249                                         ByteBuffer buf = ByteBuffer.wrap(data);
 250                                         buf.order(ByteOrder.BIG_ENDIAN);
 251                                         LTTngSessiondCmd2_4.lttng_jul_ret_code code =
 252                                                 LTTngSessiondCmd2_4.lttng_jul_ret_code.CODE_INVALID_CMD;
 253                                         buf.putInt(code.getCode());
 254                                         break;
 255                                 }
 256                         }
 257
 258                         /* Send payload to session daemon. */
 259                         this.outToSessiond.write(data, 0, data.length);
 260                         this.outToSessiond.flush();
 261                 }
 262         }
 263
 264         private String getHomePath() {
 265                 return System.getProperty("user.home");
 266         }
 267
 268         /**
 269          * Read port number from file created by the session daemon.
 270          *
 271          * @return port value if found else 0.
 272          */
 273         private int getPortFromFile(String path) throws IOException {
 274                 int port;
 275                 BufferedReader br;
 276
 277                 try {
 278                         br = new BufferedReader(new FileReader(path));
 279                         String line = br.readLine();
 280                         port = Integer.parseInt(line, 10);
 281                         if (port < 0 || port > 65535) {
 282                                 /* Invalid value. Ignore. */
 283                                 port = 0;
 284                         }
 285                         br.close();
 286                 } catch (FileNotFoundException e) {
 287                         /* No port available. */
 288                         port = 0;
 289                 }
 290
 291                 return port;
 292         }
 293
 294         private void connectToSessiond() throws Exception {
 295                 int port;
 296
 297                 if (this.handler.is_root == 1) {
 298                         port = getPortFromFile(rootPortFile);
 299                         if (port == 0) {
 300                                 /* No session daemon available. Stop and retry later. */
 301                                 throw new IOException();
 302                         }
 303                 } else {
 304                         port = getPortFromFile(getHomePath() + userPortFile);
 305                         if (port == 0) {
 306                                 /* No session daemon available. Stop and retry later. */
 307                                 throw new IOException();
 308                         }
 309                 }
 310
 311                 this.sessiondSock = new Socket(this.sessiondHost, port);
 312                 this.inFromSessiond = new DataInputStream(
 313                                 sessiondSock.getInputStream());
 314                 this.outToSessiond = new DataOutputStream(
 315                                 sessiondSock.getOutputStream());
 316         }
 317
 318         private void registerToSessiond() throws Exception {
 319                 byte data[] = new byte[8];
 320                 ByteBuffer buf = ByteBuffer.wrap(data);
 321                 String pid = ManagementFactory.getRuntimeMXBean().getName().split("@")[0];
 322
 323                 buf.putInt(this.agent_domain);
 324                 buf.putInt(Integer.parseInt(pid));
 325                 this.outToSessiond.write(data, 0, data.length);
 326                 this.outToSessiond.flush();
 327         }
 328 }