src/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/SessiondEnableEventCommand.java

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2015 EfficiOS Inc.
   5  * Copyright (C) 2015 Alexandre Montplaisir <alexmonthy@efficios.com>
   6  * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
   7  */
   8
   9 package org.lttng.ust.agent.client;
  10
  11 import java.nio.ByteBuffer;
  12 import java.nio.ByteOrder;
  13
  14 import org.lttng.ust.agent.session.EventRule;
  15 import org.lttng.ust.agent.session.LogLevelSelector;
  16
  17 /**
  18  * Session daemon command indicating to the Java agent that some events were
  19  * enabled in the tracing session.
  20  *
  21  * @author Alexandre Montplaisir
  22  * @author David Goulet
  23  */
  24 class SessiondEnableEventCommand extends SessiondCommand {
  25
  26         /** Fixed event name length. Value defined by the lttng agent protocol. */
  27         private static final int EVENT_NAME_LENGTH = 256;
  28
  29         private final boolean commandIsValid;
  30
  31         /* Parameters of the event rule being enabled */
  32         private final String eventName;
  33         private final LogLevelSelector logLevelFilter;
  34         private final String filterString;
  35
  36         public SessiondEnableEventCommand(byte[] data) {
  37                 if (data == null) {
  38                         throw new IllegalArgumentException();
  39                 }
  40                 ByteBuffer buf = ByteBuffer.wrap(data);
  41                 buf.order(ByteOrder.BIG_ENDIAN);
  42                 int logLevel = buf.getInt();
  43                 int logLevelType = buf.getInt();
  44                 logLevelFilter = new LogLevelSelector(logLevel, logLevelType);
  45
  46                 /* Read the event name */
  47                 byte[] eventNameBytes = new byte[EVENT_NAME_LENGTH];
  48                 buf.get(eventNameBytes);
  49                 eventName = new String(eventNameBytes, SESSIOND_PROTOCOL_CHARSET).trim();
  50
  51                 /* Read the filter string */
  52                 filterString = readNextString(buf);
  53
  54                 /* The command was invalid if the string could not be read correctly */
  55                 commandIsValid = (filterString != null);
  56         }
  57
  58         @Override
  59         public LttngAgentResponse execute(ILttngTcpClientListener agent) {
  60                 if (!commandIsValid) {
  61                         return LttngAgentResponse.FAILURE_RESPONSE;
  62                 }
  63
  64                 EventRule rule = new EventRule(eventName, logLevelFilter, filterString);
  65                 boolean success = agent.eventEnabled(rule);
  66                 return (success ? LttngAgentResponse.SUCESS_RESPONSE : LttngAgentResponse.FAILURE_RESPONSE);
  67         }
  68
  69         @Override
  70         public String toString() {
  71                 return "SessiondEnableEventCommand["
  72                                 + "eventName=" + eventName
  73                                 + ", logLevel=" + logLevelFilter.toString()
  74                                 + ", filterString=" + filterString
  75                                 +"]";
  76         }
  77 }