nativebridge: Add PreZygoteFork callback

It's required to clean-up the emulated enviroment (e.g. close file
descriptors) after emulated execution in doPreload() in app-zygote.

Test: NativeBridge6PreZygoteFork_test
Test: CtsSeccompHostTestCases
android.seccomp.cts.SeccompHostJUnit4DeviceTest
testAppZygoteSyscalls
both for Q.sdk_gphone_x86_arm.armeabi-v7a
Bug: 146904103

Change-Id: Id192a1647c2f405570bf196daf65b3f2a9faca42

1 files changed, 13 insertions, 0 deletions

diff --git a/libnativebridge/native_bridge.cc b/libnativebridge/native_bridge.cc
index 1a54ace2e0..b24d14ade2 100644
--- a/libnativebridge/native_bridge.cc
+++ b/libnativebridge/native_bridge.cc
@@ -103,6 +103,8 @@ enum NativeBridgeImplementationVersion {
   VENDOR_NAMESPACE_VERSION = 4,
   // The version with runtime namespaces
   RUNTIME_NAMESPACE_VERSION = 5,
+  // The version with pre-zygote-fork hook to support app-zygotes.
+  PRE_ZYGOTE_FORK_VERSION = 6,
 };
 
 // Whether we had an error at some point.
@@ -328,6 +330,17 @@ bool PreInitializeNativeBridge(const char* app_data_dir_in, const char* instruct
   return true;
 }
 
+void PreZygoteForkNativeBridge() {
+  if (NativeBridgeInitialized()) {
+    if (isCompatibleWith(PRE_ZYGOTE_FORK_VERSION)) {
+      return callbacks->preZygoteFork();
+    } else {
+      ALOGE("not compatible with version %d, preZygoteFork() isn't invoked",
+            PRE_ZYGOTE_FORK_VERSION);
+    }
+  }
+}
+
 static void SetCpuAbi(JNIEnv* env, jclass build_class, const char* field, const char* value) {
   if (value != nullptr) {
     jfieldID field_id = env->GetStaticFieldID(build_class, field, "Ljava/lang/String;");