Fix setDatatype endianness when writing to Wasm memory

include/proxy-wasm/wasm.h

@@ -448,7 +448,8 @@ inline bool WasmBase::copyToPointerSize(std::string_view s, uint64_t ptr_ptr, ui
 }
 
 template <typename T> inline bool WasmBase::setDatatype(uint64_t ptr, const T &t) {
-  return wasm_vm_->setMemory(ptr, sizeof(T), &t);
+  T value = htowasm(t, wasm_vm_->usesWasmByteOrder());
+  return wasm_vm_->setMemory(ptr, sizeof(T), &value);
 }
 
 } // namespace proxy_wasm

test/endianness_test.cc

@@ -33,6 +33,10 @@ class EndiannessContext : public TestContext {
     // opposed to output parameter.
     return static_cast<WasmResult>(3333333333U);
   }
+  uint32_t getLogLevel() override {
+    // Asymmetric byte pattern to catch host-endian writes via setDatatype.
+    return 0x02000001U;
+  }
 };
 
 class EndiannessWasm : public TestWasm {
@@ -149,6 +153,13 @@ TEST_P(EndiannessTest, WasmCallReadsBufferPassedByHost) {
   ASSERT_TRUE(test_buffer_from_host(context_)) << context_->getLog();
 }
 
+TEST_P(EndiannessTest, HostCallSetDatatype) {
+  WasmCallWord<0> test_host_set_datatype;
+  wasm_->wasm_vm()->getFunction("test_host_set_datatype", &test_host_set_datatype);
+
+  EXPECT_TRUE(test_host_set_datatype(context_)) << context_->getLog();
+}
+
 GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(EndiannessTest);
 
 } // namespace

test/test_data/endianness.rs

@@ -33,7 +33,7 @@ pub extern "C" fn _initialize() {
 }
 
 #[no_mangle]
-pub extern "C" fn proxy_abi_version_0_2_0() {}
+pub extern "C" fn proxy_abi_version_0_2_1() {}
 
 #[no_mangle]
 pub extern "C" fn proxy_on_memory_allocate(size: usize) -> *mut u8 {
@@ -177,3 +177,23 @@ pub extern "C" fn test_buffer_from_host() -> bool {
         }
     }
 }
+
+extern "C" {
+    // proxy_get_log_level writes the host log level to Wasm memory via setDatatype.
+    fn proxy_get_log_level(return_level: *mut u32) -> u32;
+}
+
+#[no_mangle]
+pub extern "C" fn test_host_set_datatype() -> u32 {
+    let mut level: u32 = 0;
+    unsafe {
+        let status = proxy_get_log_level(&mut level);
+        if status != 0 {
+            panic!("unexpected status: {}", status);
+        }
+        if level != 0x02000001 {
+            panic!("unexpected level: {}", level);
+        }
+    }
+    return 1;
+}

test/wasm_vm_test.cc

@@ -93,6 +93,31 @@ TEST_P(TestVm, Memory) {
   ASSERT_EQ(200, static_cast<int32_t>(word.u64_));
 }
 
+TEST_P(TestVm, SetDatatypeWritesLittleEndian) {
+  if (engine_ == "null") {
+    // NullVm stores host-endian values in memory.
+    return;
+  }
+  auto source = readTestWasmFile("abi_export.wasm");
+  ASSERT_FALSE(source.empty());
+  auto local_vm = makeVm(engine_);
+  TestWasm wasm(std::move(local_vm));
+  ASSERT_TRUE(wasm.load(source, false));
+  ASSERT_TRUE(wasm.initialize());
+
+  const uint64_t ptr = 0x1000;
+  const uint32_t value = 0x02000001U;
+
+  ASSERT_TRUE(wasm.setDatatype(ptr, value));
+
+  auto mem = wasm.wasm_vm()->getMemory(ptr, sizeof(uint32_t));
+  ASSERT_TRUE(mem.has_value());
+  EXPECT_EQ(static_cast<uint8_t>(mem->data()[0]), 0x01U);
+  EXPECT_EQ(static_cast<uint8_t>(mem->data()[1]), 0x00U);
+  EXPECT_EQ(static_cast<uint8_t>(mem->data()[2]), 0x00U);
+  EXPECT_EQ(static_cast<uint8_t>(mem->data()[3]), 0x02U);
+}
+
 TEST_P(TestVm, Clone) {
   if (vm_->cloneable() == proxy_wasm::Cloneable::NotCloneable) {
     return;