libbinder_ndk: log on null non-@nullable fd/binder

b/c the NDK backend C++ types can actually contain the null value, it's
not clear from the type system alone that these cannot be null or why.

Bug: 176177197
Test: with `atest CtsNdkBinderTestCases`
12-23 02:18:12.891 29957 29979 E android.binder.cts: Passing null binder
object as non-@nullable AIDL IBinder
12-23 02:18:12.902 29957 29979 E android.binder.cts: Passing -1 file
descriptor as non-@nullable AIDL ParcelFileDescriptor
12-23 02:18:13.149 29957 29979 E android.binder.cts: Passing null binder
object as non-@nullable AIDL IBinder
12-23 02:18:13.160 29957 29979 E android.binder.cts: Passing -1 file
descriptor as non-@nullable AIDL ParcelFileDescriptor
12-23 02:18:13.282 29957 29979 E android.binder.cts: Passing null binder
object as non-@nullable AIDL IBinder
12-23 02:18:13.295 29957 29979 E android.binder.cts: Passing -1 file
descriptor as non-@nullable AIDL ParcelFileDescriptor
12-23 02:18:13.452 29957 29979 E android.binder.cts: Passing null binder
object as non-@nullable AIDL IBinder
12-23 02:18:13.465 29957 29979 E android.binder.cts: Passing -1 file
descriptor as non-@nullable AIDL ParcelFileDescriptor
12-23 02:18:13.621 29957 29979 E android.binder.cts: Passing null binder
object as non-@nullable AIDL IBinder
12-23 02:18:13.634 29957 29979 E android.binder.cts: Passing -1 file
descriptor as non-@nullable AIDL ParcelFileDescriptor

Change-Id: Ic855aa85d95724e82c46e941b442ff6cbba39e77

3 files changed, 42 insertions, 8 deletions

diff --git a/libs/binder/ndk/include_cpp/android/binder_auto_utils.h b/libs/binder/ndk/include_cpp/android/binder_auto_utils.h
index c44a24ba04..53871f28a2 100644
--- a/libs/binder/ndk/include_cpp/android/binder_auto_utils.h
+++ b/libs/binder/ndk/include_cpp/android/binder_auto_utils.h
@@ -27,19 +27,12 @@
 #pragma once
 
 #include <android/binder_ibinder.h>
+#include <android/binder_internal_logging.h>
 #include <android/binder_parcel.h>
 #include <android/binder_status.h>
 
 #include <assert.h>
 
-// defined differently by liblog
-#pragma push_macro("LOG_PRI")
-#ifdef LOG_PRI
-#undef LOG_PRI
-#endif
-#include <syslog.h>
-#pragma pop_macro("LOG_PRI")
-
 #include <unistd.h>
 #include <cstddef>
 #include <string>
diff --git a/libs/binder/ndk/include_cpp/android/binder_internal_logging.h b/libs/binder/ndk/include_cpp/android/binder_internal_logging.h
new file mode 100644
index 0000000000..88c6443f71
--- /dev/null
+++ b/libs/binder/ndk/include_cpp/android/binder_internal_logging.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @addtogroup NdkBinder
+ * @{
+ */
+
+/**
+ * @file binder_internal_logging.h
+ * @brief This provides the ability to use syslog from binder headers, since
+ * other logging functionality might be inaccessable.
+ */
+
+#pragma once
+
+// defined differently by liblog
+#pragma push_macro("LOG_PRI")
+#ifdef LOG_PRI
+#undef LOG_PRI
+#endif
+#include <syslog.h>
+#pragma pop_macro("LOG_PRI")
+
+/** @} */
diff --git a/libs/binder/ndk/include_cpp/android/binder_parcel_utils.h b/libs/binder/ndk/include_cpp/android/binder_parcel_utils.h
index 054aebeb50..83190aa56e 100644
--- a/libs/binder/ndk/include_cpp/android/binder_parcel_utils.h
+++ b/libs/binder/ndk/include_cpp/android/binder_parcel_utils.h
@@ -27,6 +27,7 @@
 #pragma once
 
 #include <android/binder_auto_utils.h>
+#include <android/binder_internal_logging.h>
 #include <android/binder_parcel.h>
 
 #include <optional>
@@ -179,6 +180,7 @@ static inline binder_status_t AParcel_readNullableStrongBinder(const AParcel* pa
 static inline binder_status_t AParcel_writeRequiredStrongBinder(AParcel* parcel,
                                                                 const SpAIBinder& binder) {
     if (binder.get() == nullptr) {
+        syslog(LOG_ERR, "Passing null binder object as non-@nullable AIDL IBinder");
         return STATUS_UNEXPECTED_NULL;
     }
     return AParcel_writeStrongBinder(parcel, binder.get());
@@ -228,6 +230,7 @@ static inline binder_status_t AParcel_readNullableParcelFileDescriptor(const APa
 static inline binder_status_t AParcel_writeRequiredParcelFileDescriptor(
         AParcel* parcel, const ScopedFileDescriptor& fd) {
     if (fd.get() < 0) {
+        syslog(LOG_ERR, "Passing -1 file descriptor as non-@nullable AIDL ParcelFileDescriptor");
         return STATUS_UNEXPECTED_NULL;
     }
     return AParcel_writeParcelFileDescriptor(parcel, fd.get());