Zero-init HIDL core types (all)

hidl_pointer - already zero initialized
hidl_string - now memset to 0
hidl_array - has no pad to initialize, default initialize since we
    now expect structs to be default initialized to sane values.
hidl_vec - now memset to 0
hidl_memory - has three aligned(8) items which are always set
hidl_version - unused, but has two uint16_t entries

Zero-init HIDL core types (hidl_handle).
Has 7 padded bits at the end.

Since they are passed across processes.

Bug: 131356202
Test: print out values

Change-Id: I3979232879bb437d17d3a6f6013b53b2951a2138
Merged-In: I56bacf9ca7ac51d73449d11883c6224e214b8773
Merged-In: I8dd52e196e1585028d91d97f00861021c21ec09c
(cherry picked from commit aa79ac59c8907ea608392488f2d24889cf6778c8)

3 files changed, 28 insertions, 19 deletions

diff --git a/base/HidlSupport.cpp b/base/HidlSupport.cpp
index 8f3c057..e08bf93 100644
--- a/base/HidlSupport.cpp
+++ b/base/HidlSupport.cpp
@@ -36,27 +36,28 @@ bool debuggable() {
 }  // namespace details
 
 hidl_handle::hidl_handle() {
-    mHandle = nullptr;
-    mOwnsHandle = false;
+    memset(this, 0, sizeof(*this));
+    // mHandle = nullptr;
+    // mOwnsHandle = false;
 }
 
 hidl_handle::~hidl_handle() {
     freeHandle();
 }
 
-hidl_handle::hidl_handle(const native_handle_t *handle) {
+hidl_handle::hidl_handle(const native_handle_t* handle) : hidl_handle() {
     mHandle = handle;
     mOwnsHandle = false;
 }
 
 // copy constructor.
-hidl_handle::hidl_handle(const hidl_handle &other) {
+hidl_handle::hidl_handle(const hidl_handle& other) : hidl_handle() {
     mOwnsHandle = false;
     *this = other;
 }
 
 // move constructor.
-hidl_handle::hidl_handle(hidl_handle &&other) {
+hidl_handle::hidl_handle(hidl_handle&& other) : hidl_handle() {
     mOwnsHandle = false;
     *this = std::move(other);
 }
@@ -137,10 +138,11 @@ void hidl_handle::freeHandle() {
 
 static const char *const kEmptyString = "";
 
-hidl_string::hidl_string()
-    : mBuffer(kEmptyString),
-      mSize(0),
-      mOwnsBuffer(false) {
+hidl_string::hidl_string() {
+    memset(this, 0, sizeof(*this));
+    // mSize is zero
+    // mOwnsBuffer is false
+    mBuffer = kEmptyString;
 }
 
 hidl_string::~hidl_string() {
diff --git a/base/include/hidl/HidlInternal.h b/base/include/hidl/HidlInternal.h
index 5a08bc3..ed9f02c 100644
--- a/base/include/hidl/HidlInternal.h
+++ b/base/include/hidl/HidlInternal.h
@@ -59,6 +59,7 @@ template<typename T>
 struct hidl_pointer {
     hidl_pointer()
         : _pad(0) {
+        static_assert(sizeof(*this) == 8, "wrong size");
     }
     hidl_pointer(T* ptr) : hidl_pointer() { mPointer = ptr; }
     hidl_pointer(const hidl_pointer<T>& other) : hidl_pointer() { mPointer = other.mPointer; }
diff --git a/base/include/hidl/HidlSupport.h b/base/include/hidl/HidlSupport.h
index f09eb63..f5d9e71 100644
--- a/base/include/hidl/HidlSupport.h
+++ b/base/include/hidl/HidlSupport.h
@@ -316,11 +316,15 @@ protected:
 
 template<typename T>
 struct hidl_vec {
-    hidl_vec()
-        : mBuffer(nullptr),
-          mSize(0),
-          mOwnsBuffer(true) {
+    hidl_vec() {
         static_assert(hidl_vec<T>::kOffsetOfBuffer == 0, "wrong offset");
+
+        memset(this, 0, sizeof(*this));
+        // mSize is 0
+        // mBuffer is nullptr
+
+        // this is for consistency with the original implementation
+        mOwnsBuffer = true;
     }
 
     // Note, does not initialize primitive types.
@@ -330,18 +334,17 @@ struct hidl_vec {
         *this = other;
     }
 
-    hidl_vec(hidl_vec<T> &&other) noexcept
-    : mOwnsBuffer(false) {
+    hidl_vec(hidl_vec<T> &&other) noexcept : hidl_vec() {
         *this = std::move(other);
     }
 
-    hidl_vec(const std::initializer_list<T> list)
-            : mOwnsBuffer(true) {
+    hidl_vec(const std::initializer_list<T> list) : hidl_vec() {
         if (list.size() > UINT32_MAX) {
             details::logAlwaysFatal("hidl_vec can't hold more than 2^32 elements.");
         }
         mSize = static_cast<uint32_t>(list.size());
         mBuffer = new T[mSize];
+        mOwnsBuffer = true;
 
         size_t idx = 0;
         for (auto it = list.begin(); it != list.end(); ++it) {
@@ -357,7 +360,7 @@ struct hidl_vec {
               typename = typename std::enable_if<std::is_convertible<
                   typename std::iterator_traits<InputIterator>::iterator_category,
                   std::input_iterator_tag>::value>::type>
-    hidl_vec(InputIterator first, InputIterator last) : mOwnsBuffer(true) {
+    hidl_vec(InputIterator first, InputIterator last) : hidl_vec() {
         auto size = std::distance(first, last);
         if (size > static_cast<int64_t>(UINT32_MAX)) {
             details::logAlwaysFatal("hidl_vec can't hold more than 2^32 elements.");
@@ -367,6 +370,7 @@ struct hidl_vec {
         }
         mSize = static_cast<uint32_t>(size);
         mBuffer = new T[mSize];
+        mOwnsBuffer = true;
 
         size_t idx = 0;
         for (; first != last; ++first) {
@@ -833,7 +837,9 @@ private:
 // Version functions
 struct hidl_version {
 public:
-    constexpr hidl_version(uint16_t major, uint16_t minor) : mMajor(major), mMinor(minor) {}
+    constexpr hidl_version(uint16_t major, uint16_t minor) : mMajor(major), mMinor(minor) {
+        static_assert(sizeof(*this) == 4, "wrong size");
+    }
 
     bool operator==(const hidl_version& other) const {
         return (mMajor == other.get_major() && mMinor == other.get_minor());