nativeloader: Add Reset capabilities

In the case when VM is restarted all weak references
from the old VM become invalid. In such event NativeLoader
needs to clear the list of classloaders from old VM.

Bug: http://b/28453840
Bug: http://b/28449304
Change-Id: I2268c1e21cf940c57ddc5f0312f56b71aa702134
(cherry picked from commit be4ca3afc0636b314d676480156eb6977739dd00)

2 files changed, 13 insertions, 0 deletions

diff --git a/libnativeloader/include/nativeloader/native_loader.h b/libnativeloader/include/nativeloader/native_loader.h
index 1bd3b8f07..d606a760e 100644
--- a/libnativeloader/include/nativeloader/native_loader.h
+++ b/libnativeloader/include/nativeloader/native_loader.h
@@ -50,6 +50,9 @@ __attribute__((visibility("default")))
 android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader);
 #endif
 
+__attribute__((visibility("default")))
+void ResetNativeLoader();
+
 };  // namespace android
 
 #endif  // NATIVE_BRIDGE_H_
diff --git a/libnativeloader/native_loader.cpp b/libnativeloader/native_loader.cpp
index e20c82303..72152e737 100644
--- a/libnativeloader/native_loader.cpp
+++ b/libnativeloader/native_loader.cpp
@@ -121,6 +121,10 @@ class LibraryNamespaces {
     public_libraries_ = base::Join(sonames, ':');
   }
 
+  void Reset() {
+    namespaces_.clear();
+  }
+
  private:
   bool ReadConfig(const std::string& configFile, std::vector<std::string>* sonames) {
     // Read list of public native libraries from the config file.
@@ -172,6 +176,12 @@ void InitializeNativeLoader() {
 #endif
 }
 
+void ResetNativeLoader() {
+#if defined(__ANDROID__)
+  std::lock_guard<std::mutex> guard(g_namespaces_mutex);
+  g_namespaces->Reset();
+#endif
+}
 
 jstring CreateClassLoaderNamespace(JNIEnv* env,
                                    int32_t target_sdk_version,