Add (un)linkToDeath support to HwBinder. (727f7bf8) · Commits · e / os / android_frameworks_base

core/java/android/os/HwRemoteBinder.java

+7 −0

Original line number	Diff line number	Diff line
		@@ -39,6 +39,9 @@ public class HwRemoteBinder implements IHwBinder {
		public native final void transact(
		int code, HwParcel request, HwParcel reply, int flags);

		public native boolean linkToDeath(DeathRecipient recipient, long cookie);
		public native boolean unlinkToDeath(DeathRecipient recipient);

		private static native final long native_init();

		private native final void native_setup_empty();
		@@ -52,5 +55,9 @@ public class HwRemoteBinder implements IHwBinder {
		128 /* size */);
		}

		private static final void sendDeathNotice(DeathRecipient recipient, long cookie) {
		recipient.serviceDied(cookie);
		}

		private long mNativeContext;
		}

core/java/android/os/IHwBinder.java

+12 −0

Original line number	Diff line number	Diff line
		@@ -26,4 +26,16 @@ public interface IHwBinder {
		int code, HwParcel request, HwParcel reply, int flags);

		public IHwInterface queryLocalInterface(String descriptor);

		/**
		* Interface for receiving a callback when the process hosting a service
		* has gone away.
		*/
		public interface DeathRecipient {
		public void serviceDied(long cookie);
		}

		public boolean linkToDeath(DeathRecipient recipient, long cookie);

		public boolean unlinkToDeath(DeathRecipient recipient);
		}

core/jni/android_os_HwRemoteBinder.cpp

+261 −10

Original line number	Diff line number	Diff line
		@@ -25,6 +25,7 @@
		#include <JNIHelp.h>
		#include <android_runtime/AndroidRuntime.h>
		#include <hidl/Status.h>
		#include <ScopedUtfChars.h>
		#include <nativehelper/ScopedLocalRef.h>

		#include "core_jni_helpers.h"
		@@ -38,26 +39,196 @@ using android::AndroidRuntime;
		namespace android {

		static struct fields_t {
		jclass proxy_class;
		jfieldID contextID;
		jmethodID constructID;
		jmethodID sendDeathNotice;
		} gProxyOffsets;

		static struct class_offsets_t
		{
		jmethodID mGetName;
		} gClassOffsets;

		static JavaVM* jnienv_to_javavm(JNIEnv* env)
		{
		JavaVM* vm;
		return env->GetJavaVM(&vm) >= 0 ? vm : NULL;
		}

		static JNIEnv* javavm_to_jnienv(JavaVM* vm)
		{
		JNIEnv* env;
		return vm->GetEnv((void **)&env, JNI_VERSION_1_4) >= 0 ? env : NULL;
		}

		// ----------------------------------------------------------------------------
		class HwBinderDeathRecipient : public hardware::IBinder::DeathRecipient
		{
		public:
		HwBinderDeathRecipient(JNIEnv* env, jobject object, jlong cookie, const sp<HwBinderDeathRecipientList>& list)
		: mVM(jnienv_to_javavm(env)), mObject(env->NewGlobalRef(object)),
		mObjectWeak(NULL), mCookie(cookie), mList(list)
		{
		// These objects manage their own lifetimes so are responsible for final bookkeeping.
		// The list holds a strong reference to this object.
		list->add(this);
		}

		void binderDied(const wp<hardware::IBinder>& who)
		{
		if (mObject != NULL) {
		JNIEnv* env = javavm_to_jnienv(mVM);

		env->CallStaticVoidMethod(gProxyOffsets.proxy_class, gProxyOffsets.sendDeathNotice, mObject, mCookie);
		if (env->ExceptionCheck()) {
		ALOGE("Uncaught exception returned from death notification.");
		env->ExceptionClear();
		}

		// Serialize with our containing HwBinderDeathRecipientList so that we can't
		// delete the global ref on mObject while the list is being iterated.
		sp<HwBinderDeathRecipientList> list = mList.promote();
		if (list != NULL) {
		AutoMutex _l(list->lock());

		// Demote from strong ref to weak after binderDied() has been delivered,
		// to allow the DeathRecipient and BinderProxy to be GC'd if no longer needed.
		mObjectWeak = env->NewWeakGlobalRef(mObject);
		env->DeleteGlobalRef(mObject);
		mObject = NULL;
		}
		}
		}

		void clearReference()
		{
		sp<HwBinderDeathRecipientList> list = mList.promote();
		if (list != NULL) {
		list->remove(this);
		} else {
		ALOGE("clearReference() on JDR %p but DRL wp purged", this);
		}
		}

		bool matches(jobject obj) {
		bool result;
		JNIEnv* env = javavm_to_jnienv(mVM);

		if (mObject != NULL) {
		result = env->IsSameObject(obj, mObject);
		} else {
		jobject me = env->NewLocalRef(mObjectWeak);
		result = env->IsSameObject(obj, me);
		env->DeleteLocalRef(me);
		}
		return result;
		}

		void warnIfStillLive() {
		if (mObject != NULL) {
		// Okay, something is wrong -- we have a hard reference to a live death
		// recipient on the VM side, but the list is being torn down.
		JNIEnv* env = javavm_to_jnienv(mVM);
		ScopedLocalRef<jclass> objClassRef(env, env->GetObjectClass(mObject));
		ScopedLocalRef<jstring> nameRef(env,
		(jstring) env->CallObjectMethod(objClassRef.get(), gClassOffsets.mGetName));
		ScopedUtfChars nameUtf(env, nameRef.get());
		if (nameUtf.c_str() != NULL) {
		ALOGW("BinderProxy is being destroyed but the application did not call "
		"unlinkToDeath to unlink all of its death recipients beforehand. "
		"Releasing leaked death recipient: %s", nameUtf.c_str());
		} else {
		ALOGW("BinderProxy being destroyed; unable to get DR object name");
		env->ExceptionClear();
		}
		}
		}

		protected:
		virtual ~HwBinderDeathRecipient()
		{
		JNIEnv* env = javavm_to_jnienv(mVM);
		if (mObject != NULL) {
		env->DeleteGlobalRef(mObject);
		} else {
		env->DeleteWeakGlobalRef(mObjectWeak);
		}
		}

		private:
		JavaVM* const mVM;
		jobject mObject;
		jweak mObjectWeak; // will be a weak ref to the same VM-side DeathRecipient after binderDied()
		jlong mCookie;
		wp<HwBinderDeathRecipientList> mList;
		};
		// ----------------------------------------------------------------------------

		HwBinderDeathRecipientList::HwBinderDeathRecipientList() {
		}

		HwBinderDeathRecipientList::~HwBinderDeathRecipientList() {
		AutoMutex _l(mLock);

		for (const sp<HwBinderDeathRecipient>& deathRecipient : mList) {
		deathRecipient->warnIfStillLive();
		}
		}

		void HwBinderDeathRecipientList::add(const sp<HwBinderDeathRecipient>& recipient) {
		AutoMutex _l(mLock);

		} gFields;
		mList.push_back(recipient);
		}

		void HwBinderDeathRecipientList::remove(const sp<HwBinderDeathRecipient>& recipient) {
		AutoMutex _l(mLock);

		List< sp<HwBinderDeathRecipient> >::iterator iter;
		for (iter = mList.begin(); iter != mList.end(); iter++) {
		if (*iter == recipient) {
		mList.erase(iter);
		return;
		}
		}
		}

		sp<HwBinderDeathRecipient> HwBinderDeathRecipientList::find(jobject recipient) {
		AutoMutex _l(mLock);

		for (const sp<HwBinderDeathRecipient>& deathRecipient : mList) {
		if (deathRecipient->matches(recipient)) {
		return deathRecipient;
		}
		}
		return NULL;
		}

		Mutex& HwBinderDeathRecipientList::lock() {
		return mLock;
		}

		// static
		void JHwRemoteBinder::InitClass(JNIEnv *env) {
		ScopedLocalRef<jclass> clazz(env, FindClassOrDie(env, CLASS_PATH));
		jclass clazz = FindClassOrDie(env, CLASS_PATH);

		gFields.contextID =
		GetFieldIDOrDie(env, clazz.get(), "mNativeContext", "J");
		gProxyOffsets.proxy_class = MakeGlobalRefOrDie(env, clazz);
		gProxyOffsets.contextID =
		GetFieldIDOrDie(env, clazz, "mNativeContext", "J");
		gProxyOffsets.constructID = GetMethodIDOrDie(env, clazz, "<init>", "()V");
		gProxyOffsets.sendDeathNotice = GetStaticMethodIDOrDie(env, clazz, "sendDeathNotice",
		"(Landroid/os/IHwBinder$DeathRecipient;J)V");

		gFields.constructID = GetMethodIDOrDie(env, clazz.get(), "<init>", "()V");
		clazz = FindClassOrDie(env, "java/lang/Class");
		gClassOffsets.mGetName = GetMethodIDOrDie(env, clazz, "getName", "()Ljava/lang/String;");
		}

		// static
		sp<JHwRemoteBinder> JHwRemoteBinder::SetNativeContext(
		JNIEnv *env, jobject thiz, const sp<JHwRemoteBinder> &context) {
		sp<JHwRemoteBinder> old =
		(JHwRemoteBinder *)env->GetLongField(thiz, gFields.contextID);
		(JHwRemoteBinder *)env->GetLongField(thiz, gProxyOffsets.contextID);

		if (context != NULL) {
		context->incStrong(NULL /* id */);
		@@ -67,7 +238,7 @@ sp<JHwRemoteBinder> JHwRemoteBinder::SetNativeContext(
		old->decStrong(NULL /* id */);
		}

		env->SetLongField(thiz, gFields.contextID, (long)context.get());
		env->SetLongField(thiz, gProxyOffsets.contextID, (long)context.get());

		return old;
		}
		@@ -75,7 +246,7 @@ sp<JHwRemoteBinder> JHwRemoteBinder::SetNativeContext(
		// static
		sp<JHwRemoteBinder> JHwRemoteBinder::GetNativeContext(
		JNIEnv *env, jobject thiz) {
		return (JHwRemoteBinder *)env->GetLongField(thiz, gFields.contextID);
		return (JHwRemoteBinder *)env->GetLongField(thiz, gProxyOffsets.contextID);
		}

		// static
		@@ -84,7 +255,7 @@ jobject JHwRemoteBinder::NewObject(
		ScopedLocalRef<jclass> clazz(env, FindClassOrDie(env, CLASS_PATH));

		// XXX Have to look up the constructor here because otherwise that static
		// class initializer isn't called and gFields.constructID is undefined :(
		// class initializer isn't called and gProxyOffsets.constructID is undefined :(

		jmethodID constructID = GetMethodIDOrDie(env, clazz.get(), "<init>", "()V");

		@@ -97,6 +268,7 @@ jobject JHwRemoteBinder::NewObject(
		JHwRemoteBinder::JHwRemoteBinder(
		JNIEnv *env, jobject thiz, const sp<hardware::IBinder> &binder)
		: mBinder(binder) {
		mDeathRecipientList = new HwBinderDeathRecipientList();
		jclass clazz = env->GetObjectClass(thiz);
		CHECK(clazz != NULL);

		@@ -114,7 +286,7 @@ JHwRemoteBinder::~JHwRemoteBinder() {
		mClass = NULL;
		}

		sp<hardware::IBinder> JHwRemoteBinder::getBinder() {
		sp<hardware::IBinder> JHwRemoteBinder::getBinder() const {
		return mBinder;
		}

		@@ -122,6 +294,10 @@ void JHwRemoteBinder::setBinder(const sp<hardware::IBinder> &binder) {
		mBinder = binder;
		}

		sp<HwBinderDeathRecipientList> JHwRemoteBinder::getDeathRecipientList() const {
		return mDeathRecipientList;
		}

		} // namespace android

		////////////////////////////////////////////////////////////////////////////////
		@@ -174,6 +350,73 @@ static void JHwRemoteBinder_native_transact(
		signalExceptionForError(env, err);
		}

		static jboolean JHwRemoteBinder_linkToDeath(JNIEnv* env, jobject thiz,
		jobject recipient, jlong cookie)
		{
		if (recipient == NULL) {
		jniThrowNullPointerException(env, NULL);
		return JNI_FALSE;
		}

		sp<JHwRemoteBinder> context = JHwRemoteBinder::GetNativeContext(env, thiz);
		sp<hardware::IBinder> binder = context->getBinder();

		if (!binder->localBinder()) {
		HwBinderDeathRecipientList* list = (context->getDeathRecipientList()).get();
		sp<HwBinderDeathRecipient> jdr = new HwBinderDeathRecipient(env, recipient, cookie, list);
		status_t err = binder->linkToDeath(jdr, NULL, 0);
		if (err != NO_ERROR) {
		// Failure adding the death recipient, so clear its reference
		// now.
		jdr->clearReference();
		return JNI_FALSE;
		}
		}

		return JNI_TRUE;
		}

		static jboolean JHwRemoteBinder_unlinkToDeath(JNIEnv* env, jobject thiz,
		jobject recipient)
		{
		jboolean res = JNI_FALSE;
		if (recipient == NULL) {
		jniThrowNullPointerException(env, NULL);
		return res;
		}

		sp<JHwRemoteBinder> context = JHwRemoteBinder::GetNativeContext(env, thiz);
		sp<hardware::IBinder> binder = context->getBinder();

		if (!binder->localBinder()) {
		status_t err = NAME_NOT_FOUND;

		// If we find the matching recipient, proceed to unlink using that
		HwBinderDeathRecipientList* list = (context->getDeathRecipientList()).get();
		sp<HwBinderDeathRecipient> origJDR = list->find(recipient);
		if (origJDR != NULL) {
		wp<hardware::IBinder::DeathRecipient> dr;
		err = binder->unlinkToDeath(origJDR, NULL, 0, &dr);
		if (err == NO_ERROR && dr != NULL) {
		sp<hardware::IBinder::DeathRecipient> sdr = dr.promote();
		HwBinderDeathRecipient* jdr = static_cast<HwBinderDeathRecipient*>(sdr.get());
		if (jdr != NULL) {
		jdr->clearReference();
		}
		}
		}

		if (err == NO_ERROR \|\| err == DEAD_OBJECT) {
		res = JNI_TRUE;
		} else {
		jniThrowException(env, "java/util/NoSuchElementException",
		"Death link does not exist");
		}
		}

		return res;
		}

		static JNINativeMethod gMethods[] = {
		{ "native_init", "()J", (void *)JHwRemoteBinder_native_init },

		@@ -183,6 +426,14 @@ static JNINativeMethod gMethods[] = {
		{ "transact",
		"(IL" PACKAGE_PATH "/HwParcel;L" PACKAGE_PATH "/HwParcel;I)V",
		(void *)JHwRemoteBinder_native_transact },

		{"linkToDeath",
		"(Landroid/os/IHwBinder$DeathRecipient;J)Z",
		(void*)JHwRemoteBinder_linkToDeath},

		{"unlinkToDeath",
		"(Landroid/os/IHwBinder$DeathRecipient;)Z",
		(void*)JHwRemoteBinder_unlinkToDeath},
		};

		namespace android {

core/jni/android_os_HwRemoteBinder.h

+26 −2

Original line number	Diff line number	Diff line
		@@ -20,10 +20,33 @@
		#include <android-base/macros.h>
		#include <hwbinder/Binder.h>
		#include <jni.h>
		#include <utils/List.h>
		#include <utils/Mutex.h>
		#include <utils/RefBase.h>

		namespace android {

		// Per-IBinder death recipient bookkeeping. This is how we reconcile local jobject
		// death recipient references passed in through JNI with the permanent corresponding
		// HwBinderDeathRecipient objects.

		class HwBinderDeathRecipient;

		class HwBinderDeathRecipientList : public RefBase {
		List< sp<HwBinderDeathRecipient> > mList;
		Mutex mLock;

		public:
		HwBinderDeathRecipientList();
		~HwBinderDeathRecipientList();

		void add(const sp<HwBinderDeathRecipient>& recipient);
		void remove(const sp<HwBinderDeathRecipient>& recipient);
		sp<HwBinderDeathRecipient> find(jobject recipient);

		Mutex& lock(); // Use with care; specifically for mutual exclusion during binder death
		};

		struct JHwRemoteBinder : public RefBase {
		static void InitClass(JNIEnv *env);

		@@ -37,8 +60,9 @@ struct JHwRemoteBinder : public RefBase {
		JHwRemoteBinder(
		JNIEnv *env, jobject thiz, const sp<hardware::IBinder> &binder);

		sp<hardware::IBinder> getBinder();
		sp<hardware::IBinder> getBinder() const;
		void setBinder(const sp<hardware::IBinder> &binder);
		sp<HwBinderDeathRecipientList> getDeathRecipientList() const;

		protected:
		virtual ~JHwRemoteBinder();
		@@ -48,7 +72,7 @@ private:
		jobject mObject;

		sp<hardware::IBinder> mBinder;

		sp<HwBinderDeathRecipientList> mDeathRecipientList;
		DISALLOW_COPY_AND_ASSIGN(JHwRemoteBinder);
		};