Add hook for JVMTI agent in system server

Add a place to attach a jvmti agent into the system server in debug
builds.  This allows profiling and other investigations for performance
improvements.

Bug: none
Test: attach agent, collect result
Change-Id: I299dffb1774fdce48b9b695a614b7ab60f1307e2
Merged-In: I299dffb1774fdce48b9b695a614b7ab60f1307e2
(cherry picked from commit 1a88539df2279286695018c86485e4eb89357629)

1 files changed, 19 insertions, 1 deletions

diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index 2e4f1e39ce87..2528063f0bf8 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -40,12 +40,12 @@ import android.database.sqlite.SQLiteCompatibilityWalFlags;
 import android.database.sqlite.SQLiteGlobal;
 import android.hardware.display.DisplayManagerInternal;
 import android.net.ConnectivityModuleConnector;
-import android.net.Network;
 import android.net.NetworkStackClient;
 import android.net.TetheringManager;
 import android.os.BaseBundle;
 import android.os.Binder;
 import android.os.Build;
+import android.os.Debug;
 import android.os.Environment;
 import android.os.FactoryTest;
 import android.os.FileUtils;
@@ -497,6 +497,24 @@ public final class SystemServer {
             LocalServices.addService(SystemServiceManager.class, mSystemServiceManager);
             // Prepare the thread pool for init tasks that can be parallelized
             SystemServerInitThreadPool.get();
+            // Attach JVMTI agent if this is a debuggable build and the system property is set.
+            if (Build.IS_DEBUGGABLE) {
+                // Property is of the form "library_path=parameters".
+                String jvmtiAgent = SystemProperties.get("persist.sys.dalvik.jvmtiagent");
+                if (!jvmtiAgent.isEmpty()) {
+                    int equalIndex = jvmtiAgent.indexOf('=');
+                    String libraryPath = jvmtiAgent.substring(0, equalIndex);
+                    String parameterList =
+                            jvmtiAgent.substring(equalIndex + 1, jvmtiAgent.length());
+                    // Attach the agent.
+                    try {
+                        Debug.attachJvmtiAgent(libraryPath, parameterList, null);
+                    } catch (Exception e) {
+                        Slog.e("System", "*************************************************");
+                        Slog.e("System", "********** Failed to load jvmti plugin: " + jvmtiAgent);
+                    }
+                }
+            }
         } finally {
             traceEnd();  // InitBeforeStartServices
         }