Adding "attach-agent" to ActivityManagerShellCommand

This new command is used to attach runtime agents to a running application:

attach-agent <PROCESS> <FILE>
   Attach an agent to the specified <PROCESS>,
   which may be either a process name or a PID.

Test: m test-art-host, manual testing:
    . invalid syntax, missing arguments
    . invalid syntax, extra arguments
    . invalid numeric PID
    . invalid process name
    . valid process, not debuggable
    . valid process, missing agent
    . valid process, valid agent

Bug: 31682382

Change-Id: Ife88dbf23991dde7945d9208e54cd014bb7ecdc6

Merged-In: Ife88dbf23991dde7945d9208e54cd014bb7ecdc6

core/java/android/app/ActivityThread.java

@@ -965,6 +965,10 @@ public void dumpHeap(boolean managed, String path, ParcelFileDescriptor fd) {
             sendMessage(H.DUMP_HEAP, dhd, managed ? 1 : 0, 0, true /*async*/);
         }
 
+        public void attachAgent(String agent) {
+            sendMessage(H.ATTACH_AGENT, agent);
+        }
+
         public void setSchedulingGroup(int group) {
             // Note: do this immediately, since going into the foreground
             // should happen regardless of what pending work we have to do
@@ -1388,6 +1392,7 @@ private class H extends Handler {
         public static final int MULTI_WINDOW_MODE_CHANGED = 152;
         public static final int PICTURE_IN_PICTURE_MODE_CHANGED = 153;
         public static final int LOCAL_VOICE_INTERACTION_STARTED = 154;
+        public static final int ATTACH_AGENT = 155;
 
         String codeToString(int code) {
             if (DEBUG_MESSAGES) {
@@ -1444,6 +1449,7 @@ String codeToString(int code) {
                     case MULTI_WINDOW_MODE_CHANGED: return "MULTI_WINDOW_MODE_CHANGED";
                     case PICTURE_IN_PICTURE_MODE_CHANGED: return "PICTURE_IN_PICTURE_MODE_CHANGED";
                     case LOCAL_VOICE_INTERACTION_STARTED: return "LOCAL_VOICE_INTERACTION_STARTED";
+                    case ATTACH_AGENT: return "ATTACH_AGENT";
                 }
             }
             return Integer.toString(code);
@@ -1696,6 +1702,8 @@ public void handleMessage(Message msg) {
                 case LOCAL_VOICE_INTERACTION_STARTED:
                     handleLocalVoiceInteractionStarted((IBinder) ((SomeArgs) msg.obj).arg1,
                             (IVoiceInteractor) ((SomeArgs) msg.obj).arg2);
+                case ATTACH_AGENT:
+                    handleAttachAgent((String) msg.obj);
                     break;
             }
             Object obj = msg.obj;
@@ -2955,6 +2963,14 @@ private void handleLocalVoiceInteractionStarted(IBinder token, IVoiceInteractor
         }
     }
 
+    static final void handleAttachAgent(String agent) {
+        try {
+            VMDebug.attachAgent(agent);
+        } catch (IOException e) {
+            Slog.e(TAG, "Attaching agent failed: " + agent);
+        }
+    }
+
     private static final ThreadLocal<Intent> sCurrentBroadcastIntent = new ThreadLocal<Intent>();
 
     /**

core/java/android/app/ApplicationThreadNative.java

@@ -501,6 +501,14 @@ public boolean onTransact(int code, Parcel data, Parcel reply, int flags)
             return true;
         }
 
+        case ATTACH_AGENT_TRANSACTION:
+        {
+            data.enforceInterface(IApplicationThread.descriptor);
+            String agent = data.readString();
+            attachAgent(agent);
+            return true;
+        }
+
         case DUMP_ACTIVITY_TRANSACTION: {
             data.enforceInterface(IApplicationThread.descriptor);
             ParcelFileDescriptor fd = data.readFileDescriptor();
@@ -1303,6 +1311,14 @@ public void dumpActivity(FileDescriptor fd, IBinder token, String prefix, String
         data.recycle();
     }
 
+    public void attachAgent(String agent) throws RemoteException {
+        Parcel data = Parcel.obtain();
+        data.writeInterfaceToken(IApplicationThread.descriptor);
+        data.writeString(agent);
+        mRemote.transact(ATTACH_AGENT_TRANSACTION, data, null, IBinder.FLAG_ONEWAY);
+        data.recycle();
+    }
+
     public void setCoreSettings(Bundle coreSettings) throws RemoteException {
         Parcel data = Parcel.obtain();
         data.writeInterfaceToken(IApplicationThread.descriptor);

core/java/android/app/IApplicationThread.java

@@ -122,6 +122,7 @@ void profilerControl(boolean start, ProfilerInfo profilerInfo, int profileType)
             throws RemoteException;
     void dumpHeap(boolean managed, String path, ParcelFileDescriptor fd)
             throws RemoteException;
+    void attachAgent(String path) throws RemoteException;
     void setSchedulingGroup(int group) throws RemoteException;
     // the package has been removed, clean up internal references
     static final int PACKAGE_REMOVED = 0;
@@ -224,4 +225,5 @@ void scheduleOnNewActivityOptions(IBinder token, ActivityOptions options)
     int SCHEDULE_MULTI_WINDOW_CHANGED_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+58;
     int SCHEDULE_PICTURE_IN_PICTURE_CHANGED_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+59;
     int SCHEDULE_LOCAL_VOICE_INTERACTION_STARTED_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+60;
+    int ATTACH_AGENT_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+61;
 }

core/java/android/os/ShellCommand.java

@@ -274,7 +274,7 @@ public int handleDefaultCommands(String cmd) {
     /**
      * Implement parsing and execution of a command.  If it isn't a command you understand,
      * call {@link #handleDefaultCommands(String)} and return its result as a last resort.
-     * User {@link #getNextOption()}, {@link #getNextArg()}, and {@link #getNextArgRequired()}
+     * Use {@link #getNextOption()}, {@link #getNextArg()}, and {@link #getNextArgRequired()}
      * to process additional command line arguments.  Command output can be written to
      * {@link #getOutPrintWriter()} and errors to {@link #getErrPrintWriter()}.
      *

services/core/java/com/android/server/am/ActivityManagerService.java

@@ -21831,4 +21831,29 @@ public void killPackageDependents(String packageName, int userId) {
             Binder.restoreCallingIdentity(callingId);
         }
     }
+
+    /**
+     * Attach an agent to the specified process (proces name or PID)
+     */
+    public void attachAgent(String process, String path) {
+        try {
+            synchronized (this) {
+                ProcessRecord proc = findProcessLocked(process, UserHandle.USER_SYSTEM, "attachAgent");
+                if (proc == null || proc.thread == null) {
+                    throw new IllegalArgumentException("Unknown process: " + process);
+                }
+
+                boolean isDebuggable = "1".equals(SystemProperties.get(SYSTEM_DEBUGGABLE, "0"));
+                if (!isDebuggable) {
+                    if ((proc.info.flags & ApplicationInfo.FLAG_DEBUGGABLE) == 0) {
+                        throw new SecurityException("Process not debuggable: " + proc);
+                    }
+                }
+
+                proc.thread.attachAgent(path);
+            }
+        } catch (RemoteException e) {
+            throw new IllegalStateException("Process disappeared");
+        }
+    }
 }

services/core/java/com/android/server/am/ActivityManagerShellCommand.java

@@ -66,6 +66,8 @@ public int onCommand(String cmd) {
                     return runLenientBackgroundCheck(pw);
                 case "get-uid-state":
                     return getUidState(pw);
+                case "attach-agent":
+                    return runAttachAgent(pw);
                 default:
                     return handleDefaultCommands(cmd);
             }
@@ -183,6 +185,21 @@ int getUidState(PrintWriter pw) throws RemoteException {
         return 0;
     }
 
+    int runAttachAgent(PrintWriter pw) {
+        // TODO: revisit the permissions required for attaching agents
+        mInternal.enforceCallingPermission(android.Manifest.permission.SET_ACTIVITY_WATCHER,
+                "attach-agent");
+        String process = getNextArgRequired();
+        String agent = getNextArgRequired();
+        String opt;
+        if ((opt = getNextArg()) != null) {
+            pw.println("Error: Unknown option: " + opt);
+            return -1;
+        }
+        mInternal.attachAgent(process, agent);
+        return 0;
+    }
+
     @Override
     public void onHelp() {
         PrintWriter pw = getOutPrintWriter();
@@ -241,6 +258,8 @@ static void dumpHelp(PrintWriter pw, boolean dumping) {
             pw.println("    Optionally controls lenient background check mode, returns current mode.");
             pw.println("  get-uid-state <UID>");
             pw.println("    Gets the process state of an app given its <UID>.");
+            pw.println("  attach-agent <PROCESS> <FILE>");
+            pw.println("    Attach an agent to the specified <PROCESS>, which may be either a process name or a PID.");
         }
     }
 }