Fix library loads after split installation

Summary:
Whether we need to call `System.load` or `System.loadLibrary` depends on the context.
* `System.load` rejects paths starting with `/mnt/asec`, but [accepts paths starting with `/data`](https://cs.android.com/android/platform/superproject/main/+/main:art/libnativeloader/library_namespaces.cpp;l=78?q=%22%2Fdata:%2F%22). We can never use it to load libs from the base.apk via full path if the app is installed on sd-card
* `System.loadLibrary` considers outdated paths after a split apk is installed. It can never be used to load libraries after `/data/app` subdir is moved
* Similar concerns apply to implicit loading - implicit dependencies are resolved on the linker namespace level and that one is not updated after `/data/app` subdir is moved
* Apps installed to sd-card are killed during split installation even when --dont-kill flag is used. In that scenario we shouldn't need to bother with recovery.

This commit implements loading strategy that satisfies constraints listed above:
* `DirectSplitSoSourceWithImplicitLoads` is an SoSource supporting implicit loads and loading libs by name via `System.loadLibrary`. It works with apps installed to both internal storage and sdcard, provided that non splits were installed without killing the app.
* `DirectSplitSoSourceWithStrictPathControl` is an SoSource that does not support implicit loads and loads libs by full path via `System.load`. It works independently from split installation.
* `DirectSplitSoSourceWithImplicitLoads.recover` returns `DirectSplitSoSourceWithStrictPathControl` pointing othe same split. Base apk change can only be detected when the app is installed to the internal storage, this will not cause problems with sd-cards and will allow apps installed to /data/app to continue working after splits are installed.

Reviewed By: adicatana

Differential Revision: D54950872

fbshipit-source-id: 0100792da730fcce37055f88dc3e3951b9aa7fe0

java/com/facebook/soloader/DirectSplitSoSource.java

@@ -16,7 +16,6 @@
 
 package com.facebook.soloader;
 
-import android.annotation.SuppressLint;
 import android.os.Build;
 import android.os.StrictMode;
 import java.io.File;
@@ -26,11 +25,11 @@
 import java.util.Set;
 import javax.annotation.Nullable;
 
-public class DirectSplitSoSource extends SoSource {
-  private final String mSplitName;
+public abstract class DirectSplitSoSource extends SoSource {
+  protected final String mSplitName;
 
-  private @Nullable Manifest mManifest = null;
-  private @Nullable Set<String> mLibs = null;
+  protected @Nullable Manifest mManifest = null;
+  protected @Nullable Set<String> mLibs = null;
 
   public DirectSplitSoSource(String splitName) {
     mSplitName = splitName;
@@ -42,6 +41,13 @@ public DirectSplitSoSource(String splitName, Manifest manifest) {
     mLibs = new HashSet<String>(manifest.libs);
   }
 
+  public DirectSplitSoSource(
+      String splitName, @Nullable Manifest manifest, @Nullable Set<String> libs) {
+    mSplitName = splitName;
+    mManifest = manifest;
+    mLibs = libs;
+  }
+
   Manifest getManifest() {
     if (mManifest == null) {
       throw new IllegalStateException("prepare not called");
@@ -66,21 +72,13 @@ public int loadLibrary(String soName, int loadFlags, StrictMode.ThreadPolicy thr
     }
 
     if (mLibs.contains(soName)) {
-      if ((loadFlags & LOAD_FLAG_ALLOW_IMPLICIT_PROVISION) != 0) {
-        return LOAD_RESULT_IMPLICITLY_PROVIDED;
-      }
-
-      callSystemLoadLibrary(soName.substring(3, soName.length() - 3));
-      return LOAD_RESULT_LOADED;
+      return loadLibraryImpl(soName, loadFlags);
     }
 
     return LOAD_RESULT_NOT_FOUND;
   }
 
-  @SuppressLint("MissingSoLoaderLibrary")
-  void callSystemLoadLibrary(String name) {
-    System.loadLibrary(name);
-  }
+  protected abstract int loadLibraryImpl(String soName, int loadFlags);
 
   @Override
   @Nullable
@@ -156,9 +154,4 @@ public String[] getSoSourceAbis() {
     }
     return new String[] {mManifest.arch};
   }
-
-  @Override
-  public String getName() {
-    return "DirectSplitSoSource";
-  }
 }

java/com/facebook/soloader/DirectSplitSoSourceWithImplicitLoads.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.facebook.soloader;
+
+import android.annotation.SuppressLint;
+import android.content.Context;
+
+public class DirectSplitSoSourceWithImplicitLoads extends DirectSplitSoSource
+    implements RecoverableSoSource {
+  public DirectSplitSoSourceWithImplicitLoads(String splitName) {
+    super(splitName);
+  }
+
+  @Override
+  @SuppressLint("MissingSoLoaderLibrary")
+  protected int loadLibraryImpl(String soName, int loadFlags) {
+    if ((loadFlags & LOAD_FLAG_ALLOW_IMPLICIT_PROVISION) != 0) {
+      return LOAD_RESULT_IMPLICITLY_PROVIDED;
+    }
+
+    System.loadLibrary(soName.substring(3, soName.length() - 3));
+    return LOAD_RESULT_LOADED;
+  }
+
+  @Override
+  public String getName() {
+    return "DirectSplitSoSourceWithImplicitLoads";
+  }
+
+  @Override
+  public SoSource recover(Context context) {
+    return new DirectSplitSoSourceWithStrictPathControl(mSplitName, mManifest, mLibs);
+  }
+}

java/com/facebook/soloader/DirectSplitSoSourceWithStrictPathControl.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.facebook.soloader;
+
+import android.annotation.SuppressLint;
+import java.util.Set;
+import javax.annotation.Nullable;
+
+public class DirectSplitSoSourceWithStrictPathControl extends DirectSplitSoSource {
+  public DirectSplitSoSourceWithStrictPathControl(
+      String splitName, @Nullable Manifest manifest, @Nullable Set<String> libs) {
+    super(splitName, manifest, libs);
+  }
+
+  @Override
+  @SuppressLint("MissingSoLoaderLibrary")
+  protected int loadLibraryImpl(String soName, int loadFlags) {
+    System.load(getLibraryPath(soName));
+    return LOAD_RESULT_LOADED;
+  }
+
+  @Override
+  public String getName() {
+    return "DirectSplitSoSourceWithStrictPathControl";
+  }
+}

java/com/facebook/soloader/SoLoader.java

@@ -353,7 +353,7 @@ private static void initSoSources(Context context, int flags) throws IOException
         addSystemLoadWrapperSoSource(context, soSources);
       } else if (isEnabledBaseApkSplitSource) {
         addSystemLibSoSource(soSources);
-        soSources.add(0, new DirectSplitSoSource("base"));
+        soSources.add(0, new DirectSplitSoSourceWithImplicitLoads("base"));
       } else {
         addSystemLibSoSource(soSources);