| 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.client; |
| 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.CountDownLatch; |
| 32 | import java.util.concurrent.TimeUnit; |
| 33 | |
| 34 | import org.lttng.ust.agent.AbstractLttngAgent; |
| 35 | |
| 36 | /** |
| 37 | * Client for agents to connect to a local session daemon, using a TCP socket. |
| 38 | * |
| 39 | * @author David Goulet |
| 40 | */ |
| 41 | public class LttngTcpSessiondClient implements Runnable { |
| 42 | |
| 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"; |
| 46 | |
| 47 | private static int protocolMajorVersion = 1; |
| 48 | private static int protocolMinorVersion = 0; |
| 49 | |
| 50 | /** Command header from the session deamon. */ |
| 51 | private final CountDownLatch registrationLatch = new CountDownLatch(1); |
| 52 | |
| 53 | private Socket sessiondSock; |
| 54 | private volatile boolean quit = false; |
| 55 | |
| 56 | private DataInputStream inFromSessiond; |
| 57 | private DataOutputStream outToSessiond; |
| 58 | |
| 59 | private final AbstractLttngAgent<?> logAgent; |
| 60 | private final boolean isRoot; |
| 61 | |
| 62 | |
| 63 | /** |
| 64 | * Constructor |
| 65 | * |
| 66 | * @param logAgent |
| 67 | * The logging agent this client will operate on. |
| 68 | * @param isRoot |
| 69 | * True if this client should connect to the root session daemon, |
| 70 | * false if it should connect to the user one. |
| 71 | */ |
| 72 | public LttngTcpSessiondClient(AbstractLttngAgent<?> logAgent, boolean isRoot) { |
| 73 | this.logAgent = logAgent; |
| 74 | this.isRoot = isRoot; |
| 75 | } |
| 76 | |
| 77 | /** |
| 78 | * Wait until this client has successfully established a connection to its |
| 79 | * target session daemon. |
| 80 | * |
| 81 | * @param seconds |
| 82 | * A timeout in seconds after which this method will return |
| 83 | * anyway. |
| 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 |
| 86 | * interrupted. |
| 87 | */ |
| 88 | public boolean waitForConnection(int seconds) { |
| 89 | try { |
| 90 | return registrationLatch.await(seconds, TimeUnit.SECONDS); |
| 91 | } catch (InterruptedException e) { |
| 92 | return false; |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | @Override |
| 97 | public void run() { |
| 98 | for (;;) { |
| 99 | if (this.quit) { |
| 100 | break; |
| 101 | } |
| 102 | |
| 103 | try { |
| 104 | |
| 105 | /* |
| 106 | * Connect to the session daemon before anything else. |
| 107 | */ |
| 108 | connectToSessiond(); |
| 109 | |
| 110 | /* |
| 111 | * Register to the session daemon as the Java component of the |
| 112 | * UST application. |
| 113 | */ |
| 114 | registerToSessiond(); |
| 115 | |
| 116 | /* |
| 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. |
| 120 | */ |
| 121 | handleSessiondCmd(); |
| 122 | } catch (UnknownHostException uhe) { |
| 123 | uhe.printStackTrace(); |
| 124 | } catch (IOException ioe) { |
| 125 | try { |
| 126 | Thread.sleep(3000); |
| 127 | } catch (InterruptedException e) { |
| 128 | e.printStackTrace(); |
| 129 | } |
| 130 | } |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * Dispose this client and close any socket connection it may hold. |
| 136 | */ |
| 137 | public void close() { |
| 138 | this.quit = true; |
| 139 | |
| 140 | try { |
| 141 | if (this.sessiondSock != null) { |
| 142 | this.sessiondSock.close(); |
| 143 | } |
| 144 | } catch (IOException e) { |
| 145 | e.printStackTrace(); |
| 146 | } |
| 147 | } |
| 148 | |
| 149 | private void connectToSessiond() throws IOException { |
| 150 | int port; |
| 151 | |
| 152 | if (this.isRoot) { |
| 153 | port = getPortFromFile(ROOT_PORT_FILE); |
| 154 | if (port == 0) { |
| 155 | /* No session daemon available. Stop and retry later. */ |
| 156 | throw new IOException(); |
| 157 | } |
| 158 | } else { |
| 159 | port = getPortFromFile(getHomePath() + USER_PORT_FILE); |
| 160 | if (port == 0) { |
| 161 | /* No session daemon available. Stop and retry later. */ |
| 162 | throw new IOException(); |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | this.sessiondSock = new Socket(SESSION_HOST, port); |
| 167 | this.inFromSessiond = new DataInputStream(sessiondSock.getInputStream()); |
| 168 | this.outToSessiond = new DataOutputStream(sessiondSock.getOutputStream()); |
| 169 | } |
| 170 | |
| 171 | private static String getHomePath() { |
| 172 | return System.getProperty("user.home"); |
| 173 | } |
| 174 | |
| 175 | /** |
| 176 | * Read port number from file created by the session daemon. |
| 177 | * |
| 178 | * @return port value if found else 0. |
| 179 | */ |
| 180 | private static int getPortFromFile(String path) throws IOException { |
| 181 | int port; |
| 182 | BufferedReader br = null; |
| 183 | |
| 184 | try { |
| 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. */ |
| 190 | port = 0; |
| 191 | } |
| 192 | } catch (FileNotFoundException e) { |
| 193 | /* No port available. */ |
| 194 | port = 0; |
| 195 | } finally { |
| 196 | if (br != null) { |
| 197 | br.close(); |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | return port; |
| 202 | } |
| 203 | |
| 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]; |
| 208 | |
| 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(); |
| 215 | } |
| 216 | |
| 217 | /** |
| 218 | * Handle session command from the session daemon. |
| 219 | */ |
| 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; |
| 225 | |
| 226 | while (true) { |
| 227 | /* Get header from session daemon. */ |
| 228 | SessiondCommandHeader cmdHeader = recvHeader(); |
| 229 | |
| 230 | if (cmdHeader.getDataSize() > 0) { |
| 231 | inputData = recvPayload(cmdHeader); |
| 232 | } |
| 233 | |
| 234 | switch (cmdHeader.getCommandType()) { |
| 235 | case CMD_REG_DONE: |
| 236 | { |
| 237 | /* |
| 238 | * Countdown the registration latch, meaning registration is |
| 239 | * done and we can proceed to continue tracing. |
| 240 | */ |
| 241 | registrationLatch.countDown(); |
| 242 | /* |
| 243 | * We don't send any reply to the registration done command. |
| 244 | * This just marks the end of the initial session setup. |
| 245 | */ |
| 246 | continue; |
| 247 | } |
| 248 | case CMD_LIST: |
| 249 | { |
| 250 | ISessiondCommand listLoggerCmd = new SessiondListLoggersCommand(); |
| 251 | ILttngAgentResponse response = listLoggerCmd.execute(logAgent); |
| 252 | responseData = response.getBytes(); |
| 253 | break; |
| 254 | } |
| 255 | case CMD_ENABLE: |
| 256 | { |
| 257 | if (inputData == null) { |
| 258 | /* Invalid command */ |
| 259 | responseData = ILttngAgentResponse.FAILURE_RESPONSE.getBytes(); |
| 260 | break; |
| 261 | } |
| 262 | ISessiondCommand enableCmd = new SessiondEnableEventCommand(inputData); |
| 263 | ILttngAgentResponse response = enableCmd.execute(logAgent); |
| 264 | responseData = response.getBytes(); |
| 265 | break; |
| 266 | } |
| 267 | case CMD_DISABLE: |
| 268 | { |
| 269 | if (inputData == null) { |
| 270 | /* Invalid command */ |
| 271 | responseData = ILttngAgentResponse.FAILURE_RESPONSE.getBytes(); |
| 272 | break; |
| 273 | } |
| 274 | ISessiondCommand disableCmd = new SessiondDisableEventCommand(inputData); |
| 275 | ILttngAgentResponse response = disableCmd.execute(logAgent); |
| 276 | responseData = response.getBytes(); |
| 277 | break; |
| 278 | } |
| 279 | default: |
| 280 | { |
| 281 | /* Unknown command, send empty reply */ |
| 282 | responseData = new byte[4]; |
| 283 | ByteBuffer buf = ByteBuffer.wrap(responseData); |
| 284 | buf.order(ByteOrder.BIG_ENDIAN); |
| 285 | break; |
| 286 | } |
| 287 | } |
| 288 | |
| 289 | /* Send response to the session daemon. */ |
| 290 | this.outToSessiond.write(responseData, 0, responseData.length); |
| 291 | this.outToSessiond.flush(); |
| 292 | } |
| 293 | } |
| 294 | |
| 295 | /** |
| 296 | * Receive header data from the session daemon using the LTTng command |
| 297 | * static buffer of the right size. |
| 298 | */ |
| 299 | private SessiondCommandHeader recvHeader() throws IOException { |
| 300 | byte data[] = new byte[SessiondCommandHeader.HEADER_SIZE]; |
| 301 | |
| 302 | int readLen = this.inFromSessiond.read(data, 0, data.length); |
| 303 | if (readLen != data.length) { |
| 304 | throw new IOException(); |
| 305 | } |
| 306 | return new SessiondCommandHeader(data); |
| 307 | } |
| 308 | |
| 309 | /** |
| 310 | * Receive payload from the session daemon. This MUST be done after a |
| 311 | * recvHeader() so the header value of a command are known. |
| 312 | * |
| 313 | * The caller SHOULD use isPayload() before which returns true if a payload |
| 314 | * is expected after the header. |
| 315 | */ |
| 316 | private byte[] recvPayload(SessiondCommandHeader headerCmd) throws IOException { |
| 317 | byte payload[] = new byte[(int) headerCmd.getDataSize()]; |
| 318 | |
| 319 | /* Failsafe check so we don't waste our time reading 0 bytes. */ |
| 320 | if (payload.length == 0) { |
| 321 | return null; |
| 322 | } |
| 323 | |
| 324 | this.inFromSessiond.read(payload, 0, payload.length); |
| 325 | return payload; |
| 326 | } |
| 327 | |
| 328 | } |