commit 10b19f86d9d8bec6f47f31449593711479f336a5
author Steven Moreland <smoreland@google.com> Thu Aug 06 19:32:45 2020 +0000
committer android-build-team Robot <android-build-team-robot@google.com> Wed Sep 16 23:28:56 2020 +0000
tree cf6db00679d1f543593ab9e8e7da6626a01bc909
parent d04d08d1c78c6455f5e2d883844076ece94b235f

libbinder_ndk: fix failure when dump/shell are unset

People directly using libbinder_ndk functions who didn't create a debug
dump function function would fail to initialize that pointer, and
potentially crash. Those who didn't create a shell function were
guaranteed to crash. This wasn't noticed because the C++ wrappers which
are the recommended way to use libbinder_ndk always set these functions.

Bug: 161812320
Test: unit tests

Merged-In: I1f6909531bc640097f3f48c4a558fd03f2fa62cb
Change-Id: I1f6909531bc640097f3f48c4a558fd03f2fa62cb
(cherry picked from commit deb5346761308d9cda3a249283a482a1ce08549e)

libs/binder/ndk/test/iface.cpp

diff --git a/libs/binder/ndk/test/iface.cpp b/libs/binder/ndk/test/iface.cpp
index 64832f3..a588985 100644
--- a/libs/binder/ndk/test/iface.cpp
+++ b/libs/binder/ndk/test/iface.cpp
@@ -118,7 +118,7 @@
     AIBinder_Weak_delete(mWeakBinder);
 }
 
-binder_status_t IFoo::addService(const char* instance) {
+AIBinder* IFoo::getBinder() {
     AIBinder* binder = nullptr;
 
     if (mWeakBinder != nullptr) {
@@ -132,8 +132,18 @@
             AIBinder_Weak_delete(mWeakBinder);
         }
         mWeakBinder = AIBinder_Weak_new(binder);
+
+        // WARNING: it is important that this class does not implement debug or
+        // shell functions because it does not use special C++ wrapper
+        // functions, and so this is how we test those functions.
     }
 
+    return binder;
+}
+
+binder_status_t IFoo::addService(const char* instance) {
+    AIBinder* binder = getBinder();
+
     binder_status_t status = AServiceManager_addService(binder, instance);
     // Strong references we care about kept by remote process
     AIBinder_decStrong(binder);

libs/binder/ndk/test/include/iface/iface.h

diff --git a/libs/binder/ndk/test/include/iface/iface.h b/libs/binder/ndk/test/include/iface/iface.h
index cdf5493..d9dd64b 100644
--- a/libs/binder/ndk/test/include/iface/iface.h
+++ b/libs/binder/ndk/test/include/iface/iface.h
@@ -30,6 +30,9 @@
 
     static AIBinder_Class* kClass;
 
+    // binder representing this interface with one reference count
+    AIBinder* getBinder();
+
     // Takes ownership of IFoo
     binder_status_t addService(const char* instance);
     static ::android::sp<IFoo> getService(const char* instance, AIBinder** outBinder = nullptr);

libs/binder/ndk/test/libbinder_ndk_unit_test.cpp

diff --git a/libs/binder/ndk/test/libbinder_ndk_unit_test.cpp b/libs/binder/ndk/test/libbinder_ndk_unit_test.cpp
index fd30d87..aaf36b9 100644
--- a/libs/binder/ndk/test/libbinder_ndk_unit_test.cpp
+++ b/libs/binder/ndk/test/libbinder_ndk_unit_test.cpp
@@ -126,6 +126,26 @@
     AIBinder_decStrong(binder);
 }
 
+TEST(NdkBinder, UnimplementedDump) {
+    sp<IFoo> foo = IFoo::getService(IFoo::kSomeInstanceName);
+    ASSERT_NE(foo, nullptr);
+    AIBinder* binder = foo->getBinder();
+    EXPECT_EQ(OK, AIBinder_dump(binder, STDOUT_FILENO, nullptr, 0));
+    AIBinder_decStrong(binder);
+}
+
+TEST(NdkBinder, UnimplementedShell) {
+    // libbinder_ndk doesn't support calling shell, so we are calling from the
+    // libbinder across processes to the NDK service which doesn't implement
+    // shell
+    static const sp<android::IServiceManager> sm(android::defaultServiceManager());
+    sp<IBinder> testService = sm->getService(String16(IFoo::kSomeInstanceName));
+
+    Vector<String16> argsVec;
+    EXPECT_EQ(OK, IBinder::shellCommand(testService, STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO,
+                                        argsVec, nullptr, nullptr));
+}
+
 TEST(NdkBinder, DoubleNumber) {
     sp<IFoo> foo = IFoo::getService(IFoo::kSomeInstanceName);
     ASSERT_NE(foo, nullptr);