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-rw-r--r--libs/binder/ndk/ibinder.cpp35
-rw-r--r--libs/binder/ndk/ibinder_internal.h5
-rw-r--r--libs/binder/ndk/include_ndk/android/binder_ibinder.h5
-rw-r--r--libs/binder/ndk/tests/iface.cpp5
-rw-r--r--libs/binder/ndk/tests/include/iface/iface.h5
-rw-r--r--libs/binder/ndk/tests/libbinder_ndk_unit_test.cpp52
6 files changed, 86 insertions, 21 deletions
diff --git a/libs/binder/ndk/ibinder.cpp b/libs/binder/ndk/ibinder.cpp
index b29f22e41a..d0de7b96b5 100644
--- a/libs/binder/ndk/ibinder.cpp
+++ b/libs/binder/ndk/ibinder.cpp
@@ -101,7 +101,22 @@ bool AIBinder::associateClass(const AIBinder_Class* clazz) {
std::lock_guard<std::mutex> lock(mClazzMutex);
if (mClazz == clazz) return true;
- if (mClazz != nullptr) {
+ // If this is an ABpBinder, the first class object becomes the canonical one. The implication
+ // of this is that no API can require a proxy information to get information on how to behave.
+ // from the class itself - which should only store the interface descriptor. The functionality
+ // should be implemented by adding AIBinder_* APIs to set values on binders themselves, by
+ // setting things on AIBinder_Class which get transferred along with the binder, so that they
+ // can be read along with the BpBinder, or by modifying APIs directly (e.g. an option in
+ // onTransact).
+ //
+ // While this check is required to support linkernamespaces, one downside of it is that
+ // you may parcel code to communicate between things in the same process. However, comms
+ // between linkernamespaces like this already happen for cross-language calls like Java<->C++
+ // or Rust<->Java, and there are good stability guarantees here. This interacts with
+ // binder Stability checks exactly like any other in-process call. The stability is known
+ // to the IBinder object, so that it doesn't matter if a class object comes from
+ // a different stability level.
+ if (mClazz != nullptr && !asABpBinder()) {
const String16& currentDescriptor = mClazz->getInterfaceDescriptor();
if (newDescriptor == currentDescriptor) {
LOG(ERROR) << __func__ << ": Class descriptors '" << currentDescriptor
@@ -115,7 +130,6 @@ bool AIBinder::associateClass(const AIBinder_Class* clazz) {
}
// always a failure because we know mClazz != clazz
- // TODO(b/262463798): support multiple ABpBinder in different namespaces
return false;
}
@@ -136,8 +150,13 @@ bool AIBinder::associateClass(const AIBinder_Class* clazz) {
return false;
}
- // if this is a local object, it's not one known to libbinder_ndk
- mClazz = clazz;
+ // A local binder being set for the first time OR
+ // ignoring a proxy binder which is set multiple time, by considering the first
+ // associated class as the canonical one.
+ if (mClazz == nullptr) {
+ mClazz = clazz;
+ }
+
return true;
}
@@ -322,6 +341,10 @@ bool AIBinder_Weak_lt(const AIBinder_Weak* lhs, const AIBinder_Weak* rhs) {
return lhs->binder < rhs->binder;
}
+// WARNING: When multiple classes exist with the same interface descriptor in different
+// linkernamespaces, the first one to be associated with mClazz becomes the canonical one
+// and the only requirement on this is that the interface descriptors match. If this
+// is an ABpBinder, no other state can be referenced from mClazz.
AIBinder_Class::AIBinder_Class(const char* interfaceDescriptor, AIBinder_Class_onCreate onCreate,
AIBinder_Class_onDestroy onDestroy,
AIBinder_Class_onTransact onTransact)
@@ -629,6 +652,10 @@ binder_status_t AIBinder_prepareTransaction(AIBinder* binder, AParcel** in) {
(*in)->get()->markForBinder(binder->getBinder());
status_t status = android::OK;
+
+ // note - this is the only read of a value in clazz, and it comes with a warning
+ // on the API itself. Do not copy this design. Instead, attach data in a new
+ // version of the prepareTransaction function.
if (clazz->writeHeader) {
status = (*in)->get()->writeInterfaceToken(clazz->getInterfaceDescriptor());
}
diff --git a/libs/binder/ndk/ibinder_internal.h b/libs/binder/ndk/ibinder_internal.h
index 8699f857d4..67bb092f0f 100644
--- a/libs/binder/ndk/ibinder_internal.h
+++ b/libs/binder/ndk/ibinder_internal.h
@@ -56,6 +56,11 @@ struct AIBinder : public virtual ::android::RefBase {
// AIBinder instance is instance of this class for a local object. In order to transact on a
// remote object, this also must be set for simplicity (although right now, only the
// interfaceDescriptor from it is used).
+ //
+ // WARNING: When multiple classes exist with the same interface descriptor in different
+ // linkernamespaces, the first one to be associated with mClazz becomes the canonical one
+ // and the only requirement on this is that the interface descriptors match. If this
+ // is an ABpBinder, no other state can be referenced from mClazz.
const AIBinder_Class* mClazz;
std::mutex mClazzMutex;
};
diff --git a/libs/binder/ndk/include_ndk/android/binder_ibinder.h b/libs/binder/ndk/include_ndk/android/binder_ibinder.h
index 1af211975f..05677a8e5d 100644
--- a/libs/binder/ndk/include_ndk/android/binder_ibinder.h
+++ b/libs/binder/ndk/include_ndk/android/binder_ibinder.h
@@ -229,6 +229,11 @@ void AIBinder_Class_setOnDump(AIBinder_Class* clazz, AIBinder_onDump onDump) __I
*
* Available since API level 33.
*
+ * WARNING: this API interacts badly with linkernamespaces. For correct behavior, you must
+ * use it on all instances of a class in the same process which share the same interface
+ * descriptor. In general, it is recommended you do not use this API, because it is disabling
+ * type safety.
+ *
* \param clazz class to disable interface header on.
*/
void AIBinder_Class_disableInterfaceTokenHeader(AIBinder_Class* clazz) __INTRODUCED_IN(33);
diff --git a/libs/binder/ndk/tests/iface.cpp b/libs/binder/ndk/tests/iface.cpp
index 2afe5d2058..76acff50bf 100644
--- a/libs/binder/ndk/tests/iface.cpp
+++ b/libs/binder/ndk/tests/iface.cpp
@@ -72,6 +72,11 @@ binder_status_t IFoo_Class_onTransact(AIBinder* binder, transaction_code_t code,
AIBinder_Class* IFoo::kClass = AIBinder_Class_define(kIFooDescriptor, IFoo_Class_onCreate,
IFoo_Class_onDestroy, IFoo_Class_onTransact);
+// Defines the same class. Ordinarly, you would never want to do this, but it's done here
+// to simulate what would happen when multiple linker namespaces interact.
+AIBinder_Class* IFoo::kClassDupe = AIBinder_Class_define(
+ kIFooDescriptor, IFoo_Class_onCreate, IFoo_Class_onDestroy, IFoo_Class_onTransact);
+
class BpFoo : public IFoo {
public:
explicit BpFoo(AIBinder* binder) : mBinder(binder) {}
diff --git a/libs/binder/ndk/tests/include/iface/iface.h b/libs/binder/ndk/tests/include/iface/iface.h
index 7408d0c5a9..0a562f085d 100644
--- a/libs/binder/ndk/tests/include/iface/iface.h
+++ b/libs/binder/ndk/tests/include/iface/iface.h
@@ -30,8 +30,13 @@ class IFoo : public virtual ::android::RefBase {
static const char* kIFooDescriptor;
static AIBinder_Class* kClass;
+ static AIBinder_Class* kClassDupe;
// binder representing this interface with one reference count
+ // NOTE - this will create a new binder if it already exists. If you use
+ // getService for instance, you must pull outBinder. Don't use this without
+ // verifying isRemote or pointer equality. This is not a very good testing API - don't
+ // copy it - consider the AIDL-generated APIs instead.
AIBinder* getBinder();
// Takes ownership of IFoo
diff --git a/libs/binder/ndk/tests/libbinder_ndk_unit_test.cpp b/libs/binder/ndk/tests/libbinder_ndk_unit_test.cpp
index 9d5ef6805a..5b2532ab4e 100644
--- a/libs/binder/ndk/tests/libbinder_ndk_unit_test.cpp
+++ b/libs/binder/ndk/tests/libbinder_ndk_unit_test.cpp
@@ -55,6 +55,18 @@ constexpr char kActiveServicesNdkUnitTestService[] = "ActiveServicesNdkUnitTestS
constexpr unsigned int kShutdownWaitTime = 10;
constexpr uint64_t kContextTestValue = 0xb4e42fb4d9a1d715;
+class MyTestFoo : public IFoo {
+ binder_status_t doubleNumber(int32_t in, int32_t* out) override {
+ *out = 2 * in;
+ LOG(INFO) << "doubleNumber (" << in << ") => " << *out;
+ return STATUS_OK;
+ }
+ binder_status_t die() override {
+ ADD_FAILURE() << "die called on local instance";
+ return STATUS_OK;
+ }
+};
+
class MyBinderNdkUnitTest : public aidl::BnBinderNdkUnitTest {
ndk::ScopedAStatus repeatInt(int32_t in, int32_t* out) {
*out = in;
@@ -296,11 +308,10 @@ TEST(NdkBinder, RegisterForServiceNotificationsExisting) {
}
TEST(NdkBinder, UnimplementedDump) {
- sp<IFoo> foo = IFoo::getService(IFoo::kSomeInstanceName);
+ ndk::SpAIBinder binder;
+ sp<IFoo> foo = IFoo::getService(IFoo::kSomeInstanceName, binder.getR());
ASSERT_NE(foo, nullptr);
- AIBinder* binder = foo->getBinder();
- EXPECT_EQ(OK, AIBinder_dump(binder, STDOUT_FILENO, nullptr, 0));
- AIBinder_decStrong(binder);
+ EXPECT_EQ(OK, AIBinder_dump(binder.get(), STDOUT_FILENO, nullptr, 0));
}
TEST(NdkBinder, UnimplementedShell) {
@@ -324,6 +335,24 @@ TEST(NdkBinder, DoubleNumber) {
EXPECT_EQ(2, out);
}
+TEST(NdkBinder, ReassociateBpBinderWithSameDescriptor) {
+ ndk::SpAIBinder binder;
+ sp<IFoo> foo = IFoo::getService(IFoo::kSomeInstanceName, binder.getR());
+
+ EXPECT_TRUE(AIBinder_isRemote(binder.get()));
+
+ EXPECT_TRUE(AIBinder_associateClass(binder.get(), IFoo::kClassDupe));
+}
+
+TEST(NdkBinder, CantHaveTwoLocalBinderClassesWithSameDescriptor) {
+ sp<IFoo> foo = sp<MyTestFoo>::make();
+ ndk::SpAIBinder binder(foo->getBinder());
+
+ EXPECT_FALSE(AIBinder_isRemote(binder.get()));
+
+ EXPECT_FALSE(AIBinder_associateClass(binder.get(), IFoo::kClassDupe));
+}
+
TEST(NdkBinder, GetTestServiceStressTest) {
// libbinder has some complicated logic to make sure only one instance of
// ABpBinder is associated with each binder.
@@ -545,18 +574,6 @@ TEST(NdkBinder, LinkToDeath) {
AIBinder_decStrong(binder);
}
-class MyTestFoo : public IFoo {
- binder_status_t doubleNumber(int32_t in, int32_t* out) override {
- *out = 2 * in;
- LOG(INFO) << "doubleNumber (" << in << ") => " << *out;
- return STATUS_OK;
- }
- binder_status_t die() override {
- ADD_FAILURE() << "die called on local instance";
- return STATUS_OK;
- }
-};
-
TEST(NdkBinder, SetInheritRt) {
// functional test in binderLibTest
sp<IFoo> foo = sp<MyTestFoo>::make();
@@ -597,7 +614,8 @@ TEST(NdkBinder, GetServiceInProcess) {
sp<IFoo> foo = new MyTestFoo;
EXPECT_EQ(EX_NONE, foo->addService(kInstanceName));
- sp<IFoo> getFoo = IFoo::getService(kInstanceName);
+ ndk::SpAIBinder binder;
+ sp<IFoo> getFoo = IFoo::getService(kInstanceName, binder.getR());
EXPECT_EQ(foo.get(), getFoo.get());
int32_t out;
generated by cgit v1.2.3-59-g8ed1b (git 2.39.0) at 2025-12-26 00:33:24 +0000