Fix update logic for multi backend

This change fixes the logic to update services in
AbstractMasterSystemService when a derviced class is configured to
support multiple backends. Before this change, after an update
all PerUserService instances would point to the same backend.

Test: Built & deployed locally

Change-Id: Icfb5860bd0baa588b914375ddfae88741b8fcb9c

services/core/java/com/android/server/infra/AbstractMasterSystemService.java

@@ -684,6 +684,16 @@ public abstract class AbstractMasterSystemService<M extends AbstractMasterSystem
      */
     @GuardedBy("mLock")
     protected List<S> updateCachedServiceListLocked(@UserIdInt int userId, boolean disabled) {
+        if (mServiceNameResolver != null
+                && mServiceNameResolver.isConfiguredInMultipleMode()) {
+            // In multiple mode, we have multiple instances of AbstractPerUserSystemService, per
+            // user where each instance holds information needed to connect to a backend. An
+            // update operation in this mode needs to account for addition, deletion, change
+            // of backends and cannot be executed in the scope of a given
+            // AbstractPerUserSystemService.
+            return updateCachedServiceListMultiModeLocked(userId, disabled);
+        }
+        // isConfiguredInMultipleMode is false
         final List<S> services = getServiceListForUserLocked(userId);
         if (services == null) {
             return null;
@@ -704,6 +714,19 @@ public abstract class AbstractMasterSystemService<M extends AbstractMasterSystem
         return services;
     }
 
+    @GuardedBy("mLock")
+    private List<S> updateCachedServiceListMultiModeLocked(int userId, boolean disabled) {
+        final int resolvedUserId = ActivityManager.handleIncomingUser(Binder.getCallingPid(),
+                Binder.getCallingUid(), userId, false, false, null,
+                null);
+        List<S> services = new ArrayList<>();
+        synchronized (mLock) {
+            removeCachedServiceListLocked(resolvedUserId);
+            services = getServiceListForUserLocked(userId);
+        }
+        return services;
+    }
+
     /**
      * Gets the Settings property that defines the name of the component name used to bind this
      * service to an external service, or {@code null} when the service is not defined by such

services/core/java/com/android/server/infra/AbstractPerUserSystemService.java

@@ -154,7 +154,14 @@ public abstract class AbstractPerUserSystemService<S extends AbstractPerUserSyst
 
         if (mMaster.mServiceNameResolver != null
                 && mMaster.mServiceNameResolver.isConfiguredInMultipleMode()) {
-            updateServiceInfoListLocked();
+            // Update of multi configured mode should always happen in AbstractMasterSystemService
+            // as this class is not aware of the complete list of multiple backends. Since we
+            // should never end up in this state, it is safe to not do anything if we end up here
+            // through a different code path.
+            if (mMaster.debug) {
+                Slog.d(mTag, "Should not end up in updateLocked when "
+                        + "isConfiguredInMultipleMode is true");
+            }
         } else {
             updateServiceInfoLocked();
         }