Merge "libbinder: remove per-binder wire protocol version" am: 4068ef232a (34d8b2ca) · Commits · e / os / platform_frameworks_native

libs/binder/BpBinder.cpp

+5 −5

Original line number	Diff line number	Diff line
		@@ -261,13 +261,13 @@ status_t BpBinder::transact(
		if (code >= FIRST_CALL_TRANSACTION && code <= LAST_CALL_TRANSACTION) {
		using android::internal::Stability;

		auto category = Stability::getCategory(this);
		int16_t stability = Stability::getRepr(this);
		Stability::Level required = privateVendor ? Stability::VENDOR
		: Stability::getLocalLevel();

		if (CC_UNLIKELY(!Stability::check(category, required))) {
		if (CC_UNLIKELY(!Stability::check(stability, required))) {
		ALOGE("Cannot do a user transaction on a %s binder (%s) in a %s context.",
		category.debugString().c_str(),
		Stability::levelString(stability).c_str(),
		String8(getInterfaceDescriptor()).c_str(),
		Stability::levelString(required).c_str());
		return BAD_TYPE;

libs/binder/Parcel.cpp

+1 −1

Original line number	Diff line number	Diff line
		@@ -173,7 +173,7 @@ static void release_object(const sp<ProcessState>& proc,
		status_t Parcel::finishFlattenBinder(const sp<IBinder>& binder)
		{
		internal::Stability::tryMarkCompilationUnit(binder.get());
		int16_t rep = internal::Stability::getCategory(binder.get()).repr();
		int16_t rep = internal::Stability::getRepr(binder.get());
		return writeInt32(rep);
		}

libs/binder/Stability.cpp

+31 −71

Original line number	Diff line number	Diff line
		@@ -23,20 +23,6 @@
		namespace android {
		namespace internal {

		// the libbinder parcel format is currently unstable

		// oldest version which is supported
		constexpr uint8_t kBinderWireFormatOldest = 1;
		// current version
		constexpr uint8_t kBinderWireFormatVersion = 1;

		Stability::Category Stability::Category::currentFromLevel(Level level) {
		return {
		.version = kBinderWireFormatVersion,
		.level = level,
		};
		}

		void Stability::forceDowngradeToStability(const sp<IBinder>& binder, Level level) {
		// Downgrading a remote binder would require also copying the version from
		// the binder sent here. In practice though, we don't need to downgrade the
		@@ -44,8 +30,7 @@ void Stability::forceDowngradeToStability(const sp<IBinder>& binder, Level level
		// what we can do to it.
		LOG_ALWAYS_FATAL_IF(!binder \|\| !binder->localBinder(), "Can only downgrade local binder");

		auto stability = Category::currentFromLevel(level);
		status_t result = setRepr(binder.get(), stability.repr(), REPR_LOG \| REPR_ALLOW_DOWNGRADE);
		status_t result = setRepr(binder.get(), level, REPR_LOG \| REPR_ALLOW_DOWNGRADE);
		LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
		}

		@@ -61,41 +46,31 @@ void Stability::forceDowngradeToVendorStability(const sp<IBinder>& binder) {
		forceDowngradeToStability(binder, Level::VENDOR);
		}

		std::string Stability::Category::debugString() {
		return levelString(level) + " wire protocol version "
		+ std::to_string(version);
		}

		void Stability::markCompilationUnit(IBinder* binder) {
		auto stability = Category::currentFromLevel(getLocalLevel());
		status_t result = setRepr(binder, stability.repr(), REPR_LOG);
		status_t result = setRepr(binder, getLocalLevel(), REPR_LOG);
		LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
		}

		void Stability::markVintf(IBinder* binder) {
		auto stability = Category::currentFromLevel(Level::VINTF);
		status_t result = setRepr(binder, stability.repr(), REPR_LOG);
		status_t result = setRepr(binder, Level::VINTF, REPR_LOG);
		LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
		}

		std::string Stability::debugToString(const sp<IBinder>& binder) {
		auto stability = getCategory(binder.get());
		return stability.debugString();
		return levelString(getRepr(binder.get()));
		}

		void Stability::markVndk(IBinder* binder) {
		auto stability = Category::currentFromLevel(Level::VENDOR);
		status_t result = setRepr(binder, stability.repr(), REPR_LOG);
		status_t result = setRepr(binder, Level::VENDOR, REPR_LOG);
		LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
		}

		bool Stability::requiresVintfDeclaration(const sp<IBinder>& binder) {
		return check(getCategory(binder.get()), Level::VINTF);
		return check(getRepr(binder.get()), Level::VINTF);
		}

		void Stability::tryMarkCompilationUnit(IBinder* binder) {
		auto stability = Category::currentFromLevel(getLocalLevel());
		(void) setRepr(binder, stability.repr(), REPR_NONE);
		(void)setRepr(binder, getLocalLevel(), REPR_NONE);
		}

		Stability::Level Stability::getLocalLevel() {
		@@ -117,92 +92,77 @@ Stability::Level Stability::getLocalLevel() {
		#endif
		}

		status_t Stability::setRepr(IBinder* binder, int32_t representation, uint32_t flags) {
		status_t Stability::setRepr(IBinder* binder, int32_t setting, uint32_t flags) {
		bool log = flags & REPR_LOG;
		bool allowDowngrade = flags & REPR_ALLOW_DOWNGRADE;

		auto current = getCategory(binder);
		auto setting = Category::fromRepr(representation);

		// If we have ahold of a binder with a newer declared version, then it
		// should support older versions, and we will simply write our parcels with
		// the current wire parcel format.
		if (setting.version < kBinderWireFormatOldest) {
		// always log, because this shouldn't happen
		ALOGE("Cannot accept binder with older binder wire protocol version "
		"%u. Versions less than %u are unsupported.", setting.version,
		kBinderWireFormatOldest);
		return BAD_TYPE;
		}
		int16_t current = getRepr(binder);

		// null binder is always written w/ 'UNDECLARED' stability
		if (binder == nullptr) {
		if (setting.level == UNDECLARED) {
		if (setting == UNDECLARED) {
		return OK;
		} else {
		if (log) {
		ALOGE("Null binder written with stability %s.",
		levelString(setting.level).c_str());
		ALOGE("Null binder written with stability %s.", levelString(setting).c_str());
		}
		return BAD_TYPE;
		}
		}

		if (!isDeclaredLevel(setting.level)) {
		if (!isDeclaredLevel(setting)) {
		if (log) {
		ALOGE("Can only set known stability, not %u.", setting.level);
		ALOGE("Can only set known stability, not %d.", setting);
		}
		return BAD_TYPE;
		}
		Level levelSetting = static_cast<Level>(setting);

		if (current == setting) return OK;

		bool hasAlreadyBeenSet = current.repr() != 0;
		bool isAllowedDowngrade = allowDowngrade && check(current, setting.level);
		bool hasAlreadyBeenSet = current != Level::UNDECLARED;
		bool isAllowedDowngrade = allowDowngrade && check(current, levelSetting);
		if (hasAlreadyBeenSet && !isAllowedDowngrade) {
		if (log) {
		ALOGE("Interface being set with %s but it is already marked as %s",
		setting.debugString().c_str(),
		current.debugString().c_str());
		levelString(setting).c_str(), levelString(current).c_str());
		}
		return BAD_TYPE;
		}

		if (isAllowedDowngrade) {
		ALOGI("Interface set with %s downgraded to %s stability",
		current.debugString().c_str(),
		setting.debugString().c_str());
		ALOGI("Interface set with %s downgraded to %s stability", levelString(current).c_str(),
		levelString(setting).c_str());
		}

		BBinder* local = binder->localBinder();
		if (local != nullptr) {
		local->mStability = setting.repr();
		local->mStability = setting;
		} else {
		binder->remoteBinder()->mStability = setting.repr();
		binder->remoteBinder()->mStability = setting;
		}

		return OK;
		}

		Stability::Category Stability::getCategory(IBinder* binder) {
		int16_t Stability::getRepr(IBinder* binder) {
		if (binder == nullptr) {
		return Category::currentFromLevel(Level::UNDECLARED);
		return Level::UNDECLARED;
		}

		BBinder* local = binder->localBinder();
		if (local != nullptr) {
		return Category::fromRepr(local->mStability);
		return local->mStability;
		}

		return Category::fromRepr(binder->remoteBinder()->mStability);
		return binder->remoteBinder()->mStability;
		}

		bool Stability::check(Category provided, Level required) {
		bool stable = (provided.level & required) == required;
		bool Stability::check(int16_t provided, Level required) {
		bool stable = (provided & required) == required;

		if (provided.level != UNDECLARED && !isDeclaredLevel(provided.level)) {
		ALOGE("Unknown stability when checking interface stability %d.",
		provided.level);
		if (provided != UNDECLARED && !isDeclaredLevel(provided)) {
		ALOGE("Unknown stability when checking interface stability %d.", provided);

		stable = false;
		}
		@@ -210,11 +170,11 @@ bool Stability::check(Category provided, Level required) {
		return stable;
		}

		bool Stability::isDeclaredLevel(Level stability) {
		bool Stability::isDeclaredLevel(int32_t stability) {
		return stability == VENDOR \|\| stability == SYSTEM \|\| stability == VINTF;
		}

		std::string Stability::levelString(Level level) {
		std::string Stability::levelString(int32_t level) {
		switch (level) {
		case Level::UNDECLARED: return "undeclared stability";
		case Level::VENDOR: return "vendor stability";

libs/binder/include/binder/Stability.h

+13 −42

Original line number	Diff line number	Diff line
		@@ -44,10 +44,9 @@ namespace internal {
		// to old servers, and new servers know how to interpret the 8-byte result,
		// they can still communicate.
		//
		// Every binder object has a stability level associated with it, and when
		// communicating with a binder, we make sure that the command we sent is one
		// that it knows how to process. The summary of stability of a binder is
		// represented by a Stability::Category object.
		// This class is specifically about (1). (2) is not currently tracked by
		// libbinder for regular binder calls, and everything on the system uses the
		// same copy of libbinder.

		class Stability final {
		public:
		@@ -128,7 +127,10 @@ private:

		static void tryMarkCompilationUnit(IBinder* binder);

		enum Level : uint8_t {
		// Currently, we use int16_t for Level so that it can fit in BBinder.
		// However, on the wire, we have 4 bytes reserved for stability, so whenever
		// we ingest a Level, we always accept an int32_t.
		enum Level : int16_t {
		UNDECLARED = 0,

		VENDOR = 0b000011,
		@@ -136,37 +138,6 @@ private:
		VINTF = 0b111111,
		};

		// This is the format of stability passed on the wire. It is only 2 bytes
		// long, but 2 bytes in addition to this are reserved here. The difference
		// in size is in order to free up space in BBinder, which is fixed by
		// prebuilts inheriting from it.
		struct Category {
		static inline Category fromRepr(int16_t representation) {
		return reinterpret_cast<Category>(&representation);
		}
		int16_t repr() const { return reinterpret_cast<const int16_t>(this); }
		static inline Category currentFromLevel(Level level);

		bool operator== (const Category& o) const {
		return repr() == o.repr();
		}
		bool operator!= (const Category& o) const {
		return !(*this == o);
		}

		std::string debugString();

		// This is the version of the wire protocol associated with the host
		// process of a particular binder. As the wire protocol changes, if
		// sending a transaction to a binder with an old version, the Parcel
		// class must write parcels according to the version documented here.
		uint8_t version;

		// bitmask of Stability::Level
		Level level;
		};
		static_assert(sizeof(Category) == sizeof(int16_t));

		// returns the stability according to how this was built
		static Level getLocalLevel();

		@@ -179,18 +150,18 @@ private:
		REPR_ALLOW_DOWNGRADE = 2,
		};
		// applies stability to binder if stability level is known
		__attribute__((warn_unused_result))
		static status_t setRepr(IBinder* binder, int32_t representation, uint32_t flags);
		__attribute__((warn_unused_result)) static status_t setRepr(IBinder* binder, int32_t setting,
		uint32_t flags);

		// get stability information as encoded on the wire
		static Category getCategory(IBinder* binder);
		static int16_t getRepr(IBinder* binder);

		// whether a transaction on binder is allowed, if the transaction
		// is done from a context with a specific stability level
		static bool check(Category provided, Level required);
		static bool check(int16_t provided, Level required);

		static bool isDeclaredLevel(Level level);
		static std::string levelString(Level level);
		static bool isDeclaredLevel(int32_t level);
		static std::string levelString(int32_t level);

		Stability();
		};