Fix: dynamically fetch the session daemon port

[lttng-ust.git] / liblttng-ust-jul / org / lttng / ust / jul / LTTngTCPSessiondClient.java

diff --git a/liblttng-ust-jul/org/lttng/ust/jul/LTTngTCPSessiondClient.java b/liblttng-ust-jul/org/lttng/ust/jul/LTTngTCPSessiondClient.java
index 21c228f00bdde7a2428f4090213a28bfee6381bd..594e735a25309dea2ee21348e85204f71285561c 100644 (file)
--- a/liblttng-ust-jul/org/lttng/ust/jul/LTTngTCPSessiondClient.java
+++ b/liblttng-ust-jul/org/lttng/ust/jul/LTTngTCPSessiondClient.java
@@ -23,9 +23,12 @@ import java.nio.ByteOrder;
 import java.lang.Integer;
 import java.io.IOException;
 import java.io.BufferedOutputStream;
+import java.io.BufferedReader;
 import java.io.ByteArrayOutputStream;
 import java.io.DataOutputStream;
 import java.io.DataInputStream;
+import java.io.FileReader;
+import java.io.FileNotFoundException;
 import java.net.*;
 import java.lang.management.ManagementFactory;
 import java.util.ArrayList;
@@ -49,7 +52,6 @@ public class LTTngTCPSessiondClient {
                new LTTngSessiondCmd2_4.sessiond_hdr();
 
        private final String sessiondHost;
-       private final int sessiondPort;
        private Socket sessiondSock;
        private boolean quit = false;
 
@@ -71,9 +73,14 @@ public class LTTngTCPSessiondClient {
        private final static long timerDelay = 5 * 1000;
        private static boolean timerInitialized;
 
-       public LTTngTCPSessiondClient(String host, int port, Semaphore sem) {
+       private static final String rootPortFile = "/var/run/lttng/jul.port";
+       private static final String userPortFile = "/.lttng/jul.port";
+
+       /* Indicate if we've already release the semaphore. */
+       private boolean sem_posted = false;
+
+       public LTTngTCPSessiondClient(String host, Semaphore sem) {
                this.sessiondHost = host;
-               this.sessiondPort = port;
                this.registerSem = sem;
                this.eventTimer = new Timer();
                this.timerInitialized = false;
@@ -168,6 +175,18 @@ public class LTTngTCPSessiondClient {
                this.timerInitialized = true;
        }
 
+       /*
+        * Try to release the registerSem if it's not already done.
+        */
+       private void tryReleaseSem()
+       {
+               /* Release semaphore so we unblock the agent. */
+               if (!this.sem_posted) {
+                       this.registerSem.release();
+                       this.sem_posted = true;
+               }
+       }
+
        public void init(LTTngLogHandler handler) throws InterruptedException {
                this.handler = handler;
 
@@ -198,13 +217,13 @@ public class LTTngTCPSessiondClient {
                                 */
                                handleSessiondCmd();
                        } catch (UnknownHostException uhe) {
-                               this.registerSem.release();
+                               tryReleaseSem();
                                System.out.println(uhe);
                        } catch (IOException ioe) {
-                               this.registerSem.release();
+                               tryReleaseSem();
                                Thread.sleep(3000);
                        } catch (Exception e) {
-                               this.registerSem.release();
+                               tryReleaseSem();
                                e.printStackTrace();
                        }
                }
@@ -279,7 +298,7 @@ public class LTTngTCPSessiondClient {
                                         * Release semaphore so meaning registration is done and we
                                         * can proceed to continue tracing.
                                         */
-                                       this.registerSem.release();
+                                       tryReleaseSem();
                                        /*
                                         * We don't send any reply to the registration done command.
                                         * This just marks the end of the initial session setup.
@@ -346,8 +365,54 @@ public class LTTngTCPSessiondClient {
                }
        }
 
+       private String getHomePath() {
+               return System.getProperty("user.home");
+       }
+
+       /**
+        * Read port number from file created by the session daemon.
+        *
+        * @return port value if found else 0.
+        */
+       private int getPortFromFile(String path) throws IOException {
+               int port;
+               BufferedReader br;
+
+               try {
+                       br = new BufferedReader(new FileReader(path));
+                       String line = br.readLine();
+                       port = Integer.parseInt(line, 10);
+                       if (port < 0 || port > 65535) {
+                               /* Invalid value. Ignore. */
+                               port = 0;
+                       }
+                       br.close();
+               } catch (FileNotFoundException e) {
+                       /* No port available. */
+                       port = 0;
+               }
+
+               return port;
+       }
+
        private void connectToSessiond() throws Exception {
-               this.sessiondSock = new Socket(this.sessiondHost, this.sessiondPort);
+               int port;
+
+               if (this.handler.is_root == 1) {
+                       port = getPortFromFile(rootPortFile);
+                       if (port == 0) {
+                               /* No session daemon available. Stop and retry later. */
+                               throw new IOException();
+                       }
+               } else {
+                       port = getPortFromFile(getHomePath() + userPortFile);
+                       if (port == 0) {
+                               /* No session daemon available. Stop and retry later. */
+                               throw new IOException();
+                       }
+               }
+
+               this.sessiondSock = new Socket(this.sessiondHost, port);
                this.inFromSessiond = new DataInputStream(
                                sessiondSock.getInputStream());
                this.outToSessiond = new DataOutputStream(