Avoid null app context in StaticApplicationContextServiceFetcher.

StaticApplicationContextServiceFetcher passes the application
context to the services it creates, but sometimes the application
context can be null. Cases we've seen so far are:

- Apps that (incorrectly) call getSystemService in
  attachBaseContext. In this case the passed-in context is what
  will become the application context soon afterwards.
- ActivityThread$ApplicationThread.setHttpProxy. In this case the
  passed-in context is the system context.

In both of these cases the passed-in context is never freed, so
passing it in to the service will not result in a leak.

Bug: 27532714
Bug: 27502146
Bug: 27337770
Change-Id: I5971c67b0e699d1a77850be8a338a448a96ec7d7

diff --git a/core/java/android/app/SystemServiceRegistry.java b/core/java/android/app/SystemServiceRegistry.java
index 2987fbc..bdc4404 100644 (file)
--- a/core/java/android/app/SystemServiceRegistry.java
+++ b/core/java/android/app/SystemServiceRegistry.java
@@ -882,7 +882,12 @@ final class SystemServiceRegistry {
         public final T getService(ContextImpl ctx) {
             synchronized (StaticApplicationContextServiceFetcher.this) {
                 if (mCachedInstance == null) {
-                    mCachedInstance = createService(ctx.getApplicationContext());
+                    Context appContext = ctx.getApplicationContext();
+                    // If the application context is null, we're either in the system process or
+                    // it's the application context very early in app initialization. In both these
+                    // cases, the passed-in ContextImpl will not be freed, so it's safe to pass it
+                    // to the service. http://b/27532714 .
+                    mCachedInstance = createService(appContext != null ? appContext : ctx);
                 }
                 return mCachedInstance;
             }