Fix for the crash on big endian machine. (#197)

Signed-off-by: Konstantin Maksimov <[email protected]>

Author: knm3000

include/proxy-wasm/wasm.h

@@ -421,10 +421,20 @@ inline bool WasmBase::copyToPointerSize(std::string_view s, uint64_t ptr_ptr, ui
     }
     memcpy(p, s.data(), size);
   }
+#if defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) &&                                    \
+    __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+  if (!wasm_vm_->setWord(ptr_ptr, Word(__builtin_bswap32(pointer)))) {
+#else
   if (!wasm_vm_->setWord(ptr_ptr, Word(pointer))) {
+#endif
     return false;
   }
+#if defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) &&                                    \
+    __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+  if (!wasm_vm_->setWord(size_ptr, Word(__builtin_bswap32(size)))) {
+#else
   if (!wasm_vm_->setWord(size_ptr, Word(size))) {
+#endif
     return false;
   }
   return true;

src/exports.cc

@@ -712,7 +712,13 @@ Word writevImpl(Word fd, Word iovs, Word iovs_len, Word *nwritten_ptr) {
     }
     const uint32_t *iovec = reinterpret_cast<const uint32_t *>(memslice.value().data());
     if (iovec[1] /* buf_len */) {
+#if defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) &&                                    \
+    __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+      memslice = context->wasmVm()->getMemory(__builtin_bswap32(iovec[0]) /* buf */,
+                                              __builtin_bswap32(iovec[1]) /* buf_len */);
+#else
       memslice = context->wasmVm()->getMemory(iovec[0] /* buf */, iovec[1] /* buf_len */);
+#endif
       if (!memslice) {
         return 21; // __WASI_EFAULT
       }
@@ -744,7 +750,12 @@ Word wasi_unstable_fd_write(Word fd, Word iovs, Word iovs_len, Word nwritten_ptr
   if (result != 0) { // __WASI_ESUCCESS
     return result;
   }
+#if defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) &&                                    \
+    __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+  if (!context->wasmVm()->setWord(nwritten_ptr, Word(__builtin_bswap32(nwritten)))) {
+#else
   if (!context->wasmVm()->setWord(nwritten_ptr, Word(nwritten))) {
+#endif
     return 21; // __WASI_EFAULT
   }
   return 0; // __WASI_ESUCCESS
@@ -798,7 +809,12 @@ Word wasi_unstable_environ_get(Word environ_array_ptr, Word environ_buf) {
   auto word_size = context->wasmVm()->getWordSize();
   auto &envs = context->wasm()->envs();
   for (auto e : envs) {
+#if defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) &&                                    \
+    __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+    if (!context->wasmVm()->setWord(environ_array_ptr, __builtin_bswap32(environ_buf))) {
+#else
     if (!context->wasmVm()->setWord(environ_array_ptr, environ_buf)) {
+#endif
       return 21; // __WASI_EFAULT
     }
 
@@ -823,7 +839,12 @@ Word wasi_unstable_environ_get(Word environ_array_ptr, Word environ_buf) {
 Word wasi_unstable_environ_sizes_get(Word count_ptr, Word buf_size_ptr) {
   auto context = contextOrEffectiveContext();
   auto &envs = context->wasm()->envs();
+#if defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) &&                                    \
+    __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+  if (!context->wasmVm()->setWord(count_ptr, Word(__builtin_bswap32(envs.size())))) {
+#else
   if (!context->wasmVm()->setWord(count_ptr, Word(envs.size()))) {
+#endif
     return 21; // __WASI_EFAULT
   }
 
@@ -832,7 +853,12 @@ Word wasi_unstable_environ_sizes_get(Word count_ptr, Word buf_size_ptr) {
     // len(key) + len(value) + 1('=') + 1(null terminator)
     size += e.first.size() + e.second.size() + 2;
   }
+#if defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) &&                                    \
+    __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+  if (!context->wasmVm()->setWord(buf_size_ptr, Word(__builtin_bswap32(size)))) {
+#else
   if (!context->wasmVm()->setWord(buf_size_ptr, Word(size))) {
+#endif
     return 21; // __WASI_EFAULT
   }
   return 0; // __WASI_ESUCCESS