use population density for coarse locations

core/java/android/provider/Settings.java

@@ -9055,8 +9055,12 @@ public static boolean putFloatForUser(ContentResolver cr, String name, float val
                 "location_time_zone_detection_enabled";
 
         /**
-         * The accuracy in meters used for coarsening location for clients with only the coarse
-         * location permission.
+         * The nominal accuracy in meters used to scale the random offset applied before population
+         * density coarsening.
+         *
+         * <p>The provider directly selects the S2 coarsening level. This value can indirectly
+         * change that level when the offset crosses a population density boundary. The offset's
+         * standard deviation is one quarter of this value, subject to a minimum scale.
          *
          * @hide
          */

core/java/com/android/server/servicewatcher/CurrentUserServiceSupplier.java

@@ -159,10 +159,22 @@ public String toString() {
      */
     public static CurrentUserServiceSupplier createFromConfig(Context context, String action,
             @BoolRes int enableOverlayResId, @StringRes int nonOverlayPackageResId) {
+        return createFromConfig(context, action, enableOverlayResId, nonOverlayPackageResId,
+                /* callerPermission= */ null, /* servicePermission= */ null);
+    }
+
+    /**
+     * Creates an instance using config resources and permission requirements.
+     *
+     * @see #create(Context, String, String, String, String)
+     */
+    public static CurrentUserServiceSupplier createFromConfig(Context context, String action,
+            @BoolRes int enableOverlayResId, @StringRes int nonOverlayPackageResId,
+            @Nullable String callerPermission, @Nullable String servicePermission) {
         String explicitPackage = retrieveExplicitPackage(context, enableOverlayResId,
                 nonOverlayPackageResId);
         return CurrentUserServiceSupplier.create(context, action, explicitPackage,
-                /*callerPermission=*/null, /*servicePermission=*/null);
+                callerPermission, servicePermission);
     }
 
     /**
@@ -326,7 +338,7 @@ public BoundServiceInfo getServiceInfo() {
                 if (mContext.checkPermission(mServicePermission, Process.INVALID_PID,
                         serviceInfo.mUid) != PERMISSION_GRANTED) {
                     Log.d(TAG, serviceInfo.getComponentName().flattenToShortString()
-                            + " disqualified due to not holding " + mCallerPermission);
+                            + " disqualified due to not holding " + mServicePermission);
                     continue;
                 }
             }

core/res/AndroidManifest.xml

@@ -2308,14 +2308,8 @@
     <permission android:name="android.permission.CONTROL_AUTOMOTIVE_GNSS"
         android:protectionLevel="signature|privileged" />
 
-    <!-- @SystemApi @hide Allows an application to bind to a
-         android.service.PopulationDensityProviderService for the purpose of
-         querying population density. This prevents arbitrary clients connecting
-         to the service. The system server checks that the provider's intent
-         service explicitly sets this permission via the android:permission
-         attribute of the service.
-         This is only expected to be possessed by the system server outside of
-         tests.
+    <!-- @SystemApi @hide Allows the system server to bind to a population density provider.
+         Provider services must require this permission.
          <p>Protection level: signature
     -->
     <permission android:name="android.permission.BIND_POPULATION_DENSITY_PROVIDER_SERVICE"

core/res/res/values/config.xml

@@ -2274,15 +2274,12 @@
         <item>app.grapheneos.networklocation</item>
     </string-array>
 
-    <!-- Package name providing population density location support. -->
-    <string name="config_populationDensityProviderPackageName" translatable="false">com.android.location.populationdensity</string>
+    <!-- Package providing population density location support. -->
+    <string name="config_populationDensityProviderPackageName" translatable="false">app.grapheneos.networklocation</string>
 
-    <!-- Whether to enable population density provider overlay, which allows the population density provider to
-         be replaced by an app at run-time. When disabled, only the
-         config_populationDensityProviderPackageName package will be searched for a population density
-         provider, otherwise any system package is eligible. Anyone who wants to disable the overlay
-         mechanism can set it to false. -->
-    <bool name="config_enablePopulationDensityProviderOverlay" translatable="false">true</bool>
+    <!-- True permits an eligible system package to replace the population density provider.
+         False searches only the configured package. -->
+    <bool name="config_enablePopulationDensityProviderOverlay" translatable="false">false</bool>
 
    <!-- Package name of the extension software fallback. -->
     <string name="config_extensionFallbackPackageName" translatable="false"></string>

services/core/java/com/android/server/location/LocationManagerService.java

@@ -112,7 +112,6 @@
 import com.android.server.LocalServices;
 import com.android.server.SystemService;
 import com.android.server.location.eventlog.LocationEventLog;
-import com.android.server.location.fudger.LocationFudgerCache;
 import com.android.server.location.geofence.GeofenceManager;
 import com.android.server.location.geofence.GeofenceProxy;
 import com.android.server.location.gnss.GnssConfiguration;
@@ -266,10 +265,7 @@ void onCurrentUserChanged(int fromUserId, int toUserId) {
     private volatile @Nullable GnssManagerService mGnssManagerService = null;
     private ProxyGeocodeProvider mGeocodeProvider;
 
-    private @Nullable ProxyPopulationDensityProvider mPopulationDensityProvider = null;
-
-    // A cache for population density lookups. Used if density-based coarse locations are enabled.
-    private @Nullable LocationFudgerCache mLocationFudgerCache = null;
+    private volatile @Nullable ProxyPopulationDensityProvider mPopulationDensityProvider = null;
 
     private final Object mDeprecatedGnssBatchingLock = new Object();
     @GuardedBy("mDeprecatedGnssBatchingLock")
@@ -404,6 +400,13 @@ void addLocationProviderManager(
                 manager.setRealProvider(realProvider);
             }
             mProviderManagers.add(manager);
+
+            // Managers added after onSystemThirdPartyAppsCanStart has wired the boot-time
+            // managers must also receive the population density provider; otherwise their
+            // fudger fails closed and suppresses every coarse fix.
+            if (mPopulationDensityProvider != null) {
+                manager.setPopulationDensityProvider(mPopulationDensityProvider);
+            }
         }
     }
 
@@ -413,10 +416,10 @@ protected void setProxyPopulationDensityProvider(ProxyPopulationDensityProvider
     }
 
     @VisibleForTesting
-    protected void setLocationFudgerCache(LocationFudgerCache cache) {
-        mLocationFudgerCache = cache;
+    protected void setPopulationDensityProviderOnFudgers(
+            @Nullable ProxyPopulationDensityProvider provider) {
         for (LocationProviderManager manager : mProviderManagers) {
-            manager.setLocationFudgerCache(cache);
+            manager.setPopulationDensityProvider(provider);
         }
     }
 
@@ -575,18 +578,16 @@ void onSystemThirdPartyAppsCanStart() {
         }
 
         long startTime = System.currentTimeMillis();
-        setProxyPopulationDensityProvider(
-                ProxyPopulationDensityProvider.createAndRegister(mContext));
+        ProxyPopulationDensityProvider populationDensityProvider =
+                ProxyPopulationDensityProvider.createAndRegister(mContext);
+        setProxyPopulationDensityProvider(populationDensityProvider);
         int duration = (int) (System.currentTimeMillis() - startTime);
-        if (mPopulationDensityProvider == null) {
-            Log.e(TAG, "no population density provider found");
-        }
+        // The proxy registers its watcher even when no provider currently resolves (it binds one
+        // that appears later), so resolution state at boot is diagnostic only.
         FrameworkStatsLog.write(FrameworkStatsLog.POPULATION_DENSITY_PROVIDER_LOADING_REPORTED,
-            /* provider_null= */ (mPopulationDensityProvider == null),
+            /* provider_null= */ !populationDensityProvider.isServiceResolved(),
             /* provider_start_time_millis= */ duration);
-        if (mPopulationDensityProvider != null) {
-            setLocationFudgerCache(new LocationFudgerCache(mPopulationDensityProvider));
-        }
+        setPopulationDensityProviderOnFudgers(populationDensityProvider);
 
         if (!Flags.disableHardwareAr()) {
             // bind to hardware activity recognition

services/core/java/com/android/server/location/eventlog/LocationEventLog.java

@@ -237,6 +237,13 @@ public void logProviderDeliveredLocations(String provider, int numLocations,
         getAggregateStats(provider, identity).markLocationDelivered();
     }
 
+    /** Logs a suppressed delivery to a client whose location could not be coarsened. */
+    public void logProviderCoarseningSuppressed(String provider, CallerIdentity identity) {
+        synchronized (this) {
+            mLocationsLog.logProviderCoarseningSuppressed(provider, identity);
+        }
+    }
+
     /** Logs that a provider has entered or exited stationary throttling. */
     public void logProviderStationaryThrottled(String provider, boolean throttled,
             ProviderRequest request) {
@@ -460,6 +467,22 @@ public String toString() {
         }
     }
 
+    private static final class ProviderCoarseningSuppressedEvent extends ProviderEvent {
+
+        private final CallerIdentity mIdentity;
+
+        ProviderCoarseningSuppressedEvent(String provider, CallerIdentity identity) {
+            super(provider);
+            mIdentity = identity;
+        }
+
+        @Override
+        public String toString() {
+            return mProvider + " provider delivery suppressed (coarsening failed) for "
+                    + mIdentity;
+        }
+    }
+
     private static final class ProviderStationaryThrottledEvent extends ProviderEvent {
 
         private final boolean mStationaryThrottled;
@@ -643,6 +666,10 @@ public void logProviderDeliveredLocations(String provider, int numLocations,
             addLog(new ProviderDeliverLocationEvent(provider, numLocations, identity));
         }
 
+        public void logProviderCoarseningSuppressed(String provider, CallerIdentity identity) {
+            addLog(new ProviderCoarseningSuppressedEvent(provider, identity));
+        }
+
         private void addLog(Object logEvent) {
             this.addLog(SystemClock.elapsedRealtime(), logEvent);
         }