Allow custom keyguard transient message

TrustAgentServices can now present a transient
message on the lock screen or AoD.

Bug: 63940122
Test: call TrustAgentService#showKeyguardErrorMessage via service,
      lock device, wait for message to show up.
Change-Id: I222118787a1afb526ce7c90d46c41d0f20d8d912

5 files changed, 55 insertions, 7 deletions

diff --git a/core/java/android/app/KeyguardManager.java b/core/java/android/app/KeyguardManager.java
index d0f84c8ee0bb..ed85ca78023e 100644
--- a/core/java/android/app/KeyguardManager.java
+++ b/core/java/android/app/KeyguardManager.java
@@ -499,7 +499,7 @@ public class KeyguardManager {
                 }
             });
         } catch (RemoteException e) {
-            Log.i(TAG, "Failed to dismiss keyguard: " + e);
+            throw e.rethrowFromSystemServer();
         }
     }
 
diff --git a/core/java/android/app/trust/ITrustListener.aidl b/core/java/android/app/trust/ITrustListener.aidl
index 506dd12a36a0..65b024999a5b 100644
--- a/core/java/android/app/trust/ITrustListener.aidl
+++ b/core/java/android/app/trust/ITrustListener.aidl
@@ -24,4 +24,5 @@ package android.app.trust;
 oneway interface ITrustListener {
     void onTrustChanged(boolean enabled, int userId, int flags);
     void onTrustManagedChanged(boolean managed, int userId);
+    void onTrustError(in CharSequence message);
 }
\ No newline at end of file
diff --git a/core/java/android/app/trust/TrustManager.java b/core/java/android/app/trust/TrustManager.java
index 852cb8e09ddb..8ab0b706a1e2 100644
--- a/core/java/android/app/trust/TrustManager.java
+++ b/core/java/android/app/trust/TrustManager.java
@@ -36,9 +36,11 @@ public class TrustManager {
 
     private static final int MSG_TRUST_CHANGED = 1;
     private static final int MSG_TRUST_MANAGED_CHANGED = 2;
+    private static final int MSG_TRUST_ERROR = 3;
 
     private static final String TAG = "TrustManager";
     private static final String DATA_FLAGS = "initiatedByUser";
+    private static final String DATA_MESSAGE = "message";
 
     private final ITrustManager mService;
     private final ArrayMap<TrustListener, ITrustListener> mTrustListeners;
@@ -148,6 +150,13 @@ public class TrustManager {
                     mHandler.obtainMessage(MSG_TRUST_MANAGED_CHANGED, (managed ? 1 : 0), userId,
                             trustListener).sendToTarget();
                 }
+
+                @Override
+                public void onTrustError(CharSequence message) {
+                    Message m = mHandler.obtainMessage(MSG_TRUST_ERROR);
+                    m.getData().putCharSequence(DATA_MESSAGE, message);
+                    m.sendToTarget();
+                }
             };
             mService.registerTrustListener(iTrustListener);
             mTrustListeners.put(trustListener, iTrustListener);
@@ -221,6 +230,10 @@ public class TrustManager {
                     break;
                 case MSG_TRUST_MANAGED_CHANGED:
                     ((TrustListener)msg.obj).onTrustManagedChanged(msg.arg1 != 0, msg.arg2);
+                    break;
+                case MSG_TRUST_ERROR:
+                    final CharSequence message = msg.peekData().getCharSequence(DATA_MESSAGE);
+                    ((TrustListener)msg.obj).onTrustError(message);
             }
         }
     };
@@ -229,9 +242,9 @@ public class TrustManager {
 
         /**
          * Reports that the trust state has changed.
-         * @param enabled if true, the system believes the environment to be trusted.
-         * @param userId the user, for which the trust changed.
-         * @param flags flags specified by the trust agent when granting trust. See
+         * @param enabled If true, the system believes the environment to be trusted.
+         * @param userId The user, for which the trust changed.
+         * @param flags Flags specified by the trust agent when granting trust. See
          *     {@link android.service.trust.TrustAgentService#grantTrust(CharSequence, long, int)
          *                 TrustAgentService.grantTrust(CharSequence, long, int)}.
          */
@@ -239,9 +252,15 @@ public class TrustManager {
 
         /**
          * Reports that whether trust is managed has changed
-         * @param enabled if true, at least one trust agent is managing trust.
-         * @param userId the user, for which the state changed.
+         * @param enabled If true, at least one trust agent is managing trust.
+         * @param userId The user, for which the state changed.
          */
         void onTrustManagedChanged(boolean enabled, int userId);
+
+        /**
+         * Reports that an error happened on a TrustAgentService.
+         * @param message A message that should be displayed on the UI.
+         */
+        void onTrustError(CharSequence message);
     }
 }
diff --git a/core/java/android/service/trust/ITrustAgentServiceCallback.aidl b/core/java/android/service/trust/ITrustAgentServiceCallback.aidl
index 14df7cb9e1a1..220e498df8a8 100644
--- a/core/java/android/service/trust/ITrustAgentServiceCallback.aidl
+++ b/core/java/android/service/trust/ITrustAgentServiceCallback.aidl
@@ -32,4 +32,5 @@ oneway interface ITrustAgentServiceCallback {
     void isEscrowTokenActive(long handle, int userId);
     void removeEscrowToken(long handle, int userId);
     void unlockUserWithToken(long handle, in byte[] token, int userId);
+    void showKeyguardErrorMessage(in CharSequence message);
 }
diff --git a/core/java/android/service/trust/TrustAgentService.java b/core/java/android/service/trust/TrustAgentService.java
index 4bade9f9f9ca..40e84b9604e7 100644
--- a/core/java/android/service/trust/TrustAgentService.java
+++ b/core/java/android/service/trust/TrustAgentService.java
@@ -18,6 +18,7 @@ package android.service.trust;
 
 import android.Manifest;
 import android.annotation.IntDef;
+import android.annotation.NonNull;
 import android.annotation.SdkConstant;
 import android.annotation.SystemApi;
 import android.app.Service;
@@ -37,6 +38,7 @@ import android.os.UserHandle;
 import android.os.UserManager;
 import android.util.Log;
 import android.util.Slog;
+
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.List;
@@ -301,7 +303,7 @@ public class TrustAgentService extends Service {
     public void onDeviceUnlockLockout(long timeoutMs) {
     }
 
-  /**
+    /**
      * Called when an escrow token is added for user userId.
      *
      * @param token the added token
@@ -561,6 +563,31 @@ public class TrustAgentService extends Service {
         }
     }
 
+    /**
+     * Request showing a transient error message on the keyguard.
+     * The message will be visible on the lock screen or always on display if possible but can be
+     * overridden by other keyguard events of higher priority - eg. fingerprint auth error.
+     * Other trust agents may override your message if posted simultaneously.
+     *
+     * @param message Message to show.
+     */
+    public final void showKeyguardErrorMessage(@NonNull CharSequence message) {
+        if (message == null) {
+            throw new IllegalArgumentException("message cannot be null");
+        }
+        synchronized (mLock) {
+            if (mCallback == null) {
+                Slog.w(TAG, "Cannot show message because service is not connected to framework.");
+                throw new IllegalStateException("Trust agent is not connected");
+            }
+            try {
+                mCallback.showKeyguardErrorMessage(message);
+            } catch (RemoteException e) {
+                onError("calling showKeyguardErrorMessage");
+            }
+        }
+    }
+
     @Override
     public final IBinder onBind(Intent intent) {
         if (DEBUG) Slog.v(TAG, "onBind() intent = " + intent);