Receive the event filter string in the Java agent

Update to agent protocol 2.0, which now sends the filter string as part
of the "enable event" command.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/LttngTcpSessiondClient.java b/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/LttngTcpSessiondClient.java
index d8788d320c416a9b9538bed603f7a9b45a8ca4cf..6cf971384260524869026351e868cfd5a4b608c2 100644 (file)
--- a/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/LttngTcpSessiondClient.java
+++ b/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/LttngTcpSessiondClient.java
@@ -42,8 +42,8 @@ public class LttngTcpSessiondClient implements Runnable {
        private static final String ROOT_PORT_FILE = "/var/run/lttng/agent.port";
        private static final String USER_PORT_FILE = "/.lttng/agent.port";
 
-       private static int protocolMajorVersion = 1;
-       private static int protocolMinorVersion = 0;
+       private static final int PROTOCOL_MAJOR_VERSION = 2;
+       private static final int PROTOCOL_MINOR_VERSION = 0;
 
        /** Command header from the session deamon. */
        private final CountDownLatch registrationLatch = new CountDownLatch(1);
@@ -211,8 +211,8 @@ public class LttngTcpSessiondClient implements Runnable {
 
                buf.putInt(domainValue);
                buf.putInt(Integer.parseInt(pid));
-               buf.putInt(protocolMajorVersion);
-               buf.putInt(protocolMinorVersion);
+               buf.putInt(PROTOCOL_MAJOR_VERSION);
+               buf.putInt(PROTOCOL_MINOR_VERSION);
                this.outToSessiond.write(data, 0, data.length);
                this.outToSessiond.flush();
        }

diff --git a/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/SessiondEnableEventCommand.java b/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/SessiondEnableEventCommand.java
index 388edc7d328afcaaf1134cc5f45d2d5023b60b6c..c9183d19d9736d2f2cf3f0fab85239c3b6d3d2dd 100644 (file)
--- a/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/SessiondEnableEventCommand.java
+++ b/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/SessiondEnableEventCommand.java
@@ -33,7 +33,10 @@ import org.lttng.ust.agent.session.LogLevelSelector;
  */
 class SessiondEnableEventCommand implements ISessiondCommand {
 
-       private static final int INT_SIZE = 4;
+       /** Fixed event name length. Value defined by the lttng agent protocol. */
+       private static final int EVENT_NAME_LENGTH = 256;
+
+       private final boolean commandIsValid;
 
        /* Parameters of the event rule being enabled */
        private final String eventName;
@@ -44,20 +47,54 @@ class SessiondEnableEventCommand implements ISessiondCommand {
                if (data == null) {
                        throw new IllegalArgumentException();
                }
-               int dataOffset = INT_SIZE * 2;
-
                ByteBuffer buf = ByteBuffer.wrap(data);
                buf.order(ByteOrder.LITTLE_ENDIAN);
                int logLevel = buf.getInt();
                int logLevelType = buf.getInt();
                logLevelFilter = new LogLevelSelector(logLevel, logLevelType);
 
-               eventName = new String(data, dataOffset, data.length - dataOffset).trim();
-               filterString = null; /* Not yet sent by the sessiond */
+               /* Read the event name */
+               byte[] eventNameBytes = new byte[EVENT_NAME_LENGTH];
+               buf.get(eventNameBytes);
+               eventName = new String(eventNameBytes).trim();
+
+               /*
+                * Read the filter string. The buffer contains the length (number of
+                * bytes), then the bytes themselves.
+                *
+                * The length is represented as an unsigned int, but it should never
+                * be greater than Integer.MAX_VALUE.
+                */
+               int filterStringLength = buf.getInt();
+               if (filterStringLength < 0) {
+                       /*
+                        * The (unsigned) length is above what the sessiond should send. The
+                        * command cannot be processed.
+                        */
+                       filterString = null;
+                       commandIsValid = false;
+                       return;
+               }
+               if (filterStringLength == 0) {
+                       /* There is explicitly no filter string */
+                       filterString = "";
+                       commandIsValid = true;
+                       return;
+               }
+
+               byte[] filterStringBytes = new byte[filterStringLength];
+               buf.get(filterStringBytes);
+               filterString = new String(filterStringBytes).trim();
+
+               commandIsValid = true;
        }
 
        @Override
        public LttngAgentResponse execute(ILttngTcpClientListener agent) {
+               if (!commandIsValid) {
+                       return LttngAgentResponse.FAILURE_RESPONSE;
+               }
+
                EventRule rule = new EventRule(eventName, logLevelFilter, filterString);
                boolean success = agent.eventEnabled(rule);
                return (success ? LttngAgentResponse.SUCESS_RESPONSE : LttngAgentResponse.FAILURE_RESPONSE);