Zygote: Load system server code early (76b4b2c3) · Commits · e / os / android_frameworks_base

core/java/com/android/internal/os/ZygoteInit.java

+40 −7

Original line number	Diff line number	Diff line
		@@ -122,6 +122,12 @@ public class ZygoteInit {

		private static boolean sPreloadComplete;

		/**
		* Cached classloader to use for the system server. Will only be populated in the system
		* server process.
		*/
		private static ClassLoader sCachedSystemServerClassLoader = null;

		static void preload(TimingsTraceLog bootTimingsTraceLog) {
		Log.d(TAG, "begin preload");
		bootTimingsTraceLog.traceBegin("BeginPreload");
		@@ -443,7 +449,13 @@ public class ZygoteInit {

		final String systemServerClasspath = Os.getenv("SYSTEMSERVERCLASSPATH");
		if (systemServerClasspath != null) {
		performSystemServerDexOpt(systemServerClasspath);
		if (performSystemServerDexOpt(systemServerClasspath)) {
		// Throw away the cached classloader. If we compiled here, the classloader would
		// not have had AoT-ed artifacts.
		// Note: This only works in a very special environment where selinux enforcement is
		// disabled, e.g., Mac builds.
		sCachedSystemServerClassLoader = null;
		}
		// Capturing profiles is only supported for debug or eng builds since selinux normally
		// prevents it.
		boolean profileSystemServer = SystemProperties.getBoolean(
		@@ -476,10 +488,9 @@ public class ZygoteInit {

		throw new IllegalStateException("Unexpected return from WrapperInit.execApplication");
		} else {
		ClassLoader cl = null;
		if (systemServerClasspath != null) {
		cl = createPathClassLoader(systemServerClasspath, parsedArgs.mTargetSdkVersion);

		createSystemServerClassLoader();
		ClassLoader cl = sCachedSystemServerClassLoader;
		if (cl != null) {
		Thread.currentThread().setContextClassLoader(cl);
		}

		@@ -493,6 +504,24 @@ public class ZygoteInit {
		/* should never reach here */
		}

		/**
		* Create the classloader for the system server and store it in
		* {@link sCachedSystemServerClassLoader}. This function may be called through JNI in
		* system server startup, when the runtime is in a critically low state. Do not do
		* extended computation etc here.
		*/
		private static void createSystemServerClassLoader() {
		if (sCachedSystemServerClassLoader != null) {
		return;
		}
		final String systemServerClasspath = Os.getenv("SYSTEMSERVERCLASSPATH");
		// TODO: Should we run optimization here?
		if (systemServerClasspath != null) {
		sCachedSystemServerClassLoader = createPathClassLoader(systemServerClasspath,
		VMRuntime.SDK_VERSION_CUR_DEVELOPMENT);
		}
		}

		/**
		* Note that preparing the profiles for system server does not require special selinux
		* permissions. From the installer perspective the system server is a regular package which can
		@@ -557,15 +586,16 @@ public class ZygoteInit {

		/**
		* Performs dex-opt on the elements of {@code classPath}, if needed. We choose the instruction
		* set of the current runtime.
		* set of the current runtime. If something was compiled, return true.
		*/
		private static void performSystemServerDexOpt(String classPath) {
		private static boolean performSystemServerDexOpt(String classPath) {
		final String[] classPathElements = classPath.split(":");
		final IInstalld installd = IInstalld.Stub
		.asInterface(ServiceManager.getService("installd"));
		final String instructionSet = VMRuntime.getRuntime().vmInstructionSet();

		String classPathForElement = "";
		boolean compiledSomething = false;
		for (String classPathElement : classPathElements) {
		// System server is fully AOTed and never profiled
		// for profile guided compilation.
		@@ -607,6 +637,7 @@ public class ZygoteInit {
		uuid, classLoaderContext, seInfo, false /* downgrade */,
		targetSdkVersion, /profileName/ null, /dexMetadataPath/ null,
		"server-dexopt");
		compiledSomething = true;
		} catch (RemoteException \| ServiceSpecificException e) {
		// Ignore (but log), we need this on the classpath for fallback mode.
		Log.w(TAG, "Failed compiling classpath element for system server: "
		@@ -617,6 +648,8 @@ public class ZygoteInit {
		classPathForElement = encodeSystemServerClassPath(
		classPathForElement, classPathElement);
		}

		return compiledSomething;
		}

		/**

core/jni/com_android_internal_os_Zygote.cpp

+23 −2

Original line number	Diff line number	Diff line
		@@ -111,11 +111,16 @@ static pid_t gSystemServerPid = 0;

		static const char kIsolatedStorage[] = "persist.sys.isolated_storage";
		static const char kIsolatedStorageSnapshot[] = "sys.isolated_storage_snapshot";
		static const char kZygoteClassName[] = "com/android/internal/os/Zygote";

		static constexpr const char* kZygoteClassName = "com/android/internal/os/Zygote";
		static jclass gZygoteClass;
		static jmethodID gCallPostForkSystemServerHooks;
		static jmethodID gCallPostForkChildHooks;

		static constexpr const char* kZygoteInitClassName = "com/android/internal/os/ZygoteInit";
		static jclass gZygoteInitClass;
		static jmethodID gCreateSystemServerClassLoader;

		static bool g_is_security_enforced = true;

		/**
		@@ -1420,6 +1425,15 @@ static void SpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray gids,
		fail_fn("Error calling post fork system server hooks.");
		}

		// Prefetch the classloader for the system server. This is done early to
		// allow a tie-down of the proper system server selinux domain.
		env->CallStaticVoidMethod(gZygoteInitClass, gCreateSystemServerClassLoader);
		if (env->ExceptionCheck()) {
		// Be robust here. The Java code will attempt to create the classloader
		// at a later point (but may not have rights to use AoT artifacts).
		env->ExceptionClear();
		}

		// TODO(oth): Remove hardcoded label here (b/117874058).
		static const char* kSystemServerLabel = "u:r:system_server:s0";
		if (selinux_android_setcon(kSystemServerLabel) != 0) {
		@@ -1986,6 +2000,13 @@ int register_com_android_internal_os_Zygote(JNIEnv* env) {
		gCallPostForkChildHooks = GetStaticMethodIDOrDie(env, gZygoteClass, "callPostForkChildHooks",
		"(IZZLjava/lang/String;)V");

		return RegisterMethodsOrDie(env, "com/android/internal/os/Zygote", gMethods, NELEM(gMethods));
		gZygoteInitClass = MakeGlobalRefOrDie(env, FindClassOrDie(env, kZygoteInitClassName));
		gCreateSystemServerClassLoader = GetStaticMethodIDOrDie(env, gZygoteInitClass,
		"createSystemServerClassLoader",
		"()V");

		RegisterMethodsOrDie(env, "com/android/internal/os/Zygote", gMethods, NELEM(gMethods));

		return JNI_OK;
		}
		} // namespace android