sea: add ability to embed auxiliary data asset for use with sea

lib/internal/util.js

@@ -54,6 +54,8 @@ const {
   overrideStackTrace,
 } = require('internal/errors');
 const { signals } = internalBinding('constants').os;
+const { getEmbeddedData } = internalBinding('sea');
+
 const {
   isArrayBufferDetached: _isArrayBufferDetached,
   guessHandleType: _guessHandleType,
@@ -874,6 +876,7 @@ class WeakReference {
 }
 
 module.exports = {
+  getEmbeddedData,
   getLazy,
   assertCrypto,
   cachedResult,

lib/util.js

@@ -77,6 +77,7 @@ const {
   promisify,
   toUSVString,
   defineLazyProperties,
+  getEmbeddedData,
 } = require('internal/util');
 
 let abortController;
@@ -384,6 +385,7 @@ module.exports = {
   formatWithOptions,
   getSystemErrorMap,
   getSystemErrorName,
+  getEmbeddedData,
   inherits,
   inspect,
   isArray: ArrayIsArray,

src/node_sea.cc

@@ -257,6 +257,42 @@ void GetCodeCache(const FunctionCallbackInfo<Value>& args) {
   args.GetReturnValue().Set(data_view);
 }
 
+#define POSTJECT_SENTINEL_EMBED "NODE_EMBED_fce680ab2cc467b6e072b8b5df1996b2"
+static inline bool hasEmbeddedData() {
+  static const volatile char* sentinel = POSTJECT_SENTINEL_EMBED ":0";
+  return sentinel[sizeof(POSTJECT_SENTINEL_EMBED)] == '1';
+}
+#undef POSTJECT_SENTINEL_EMBED
+void GetEmbeddedData(const FunctionCallbackInfo<Value>& args) {
+  if (!hasEmbeddedData()) {
+    return;
+  }
+
+  Isolate* isolate = args.GetIsolate();
+  size_t size = 0;
+#ifdef __APPLE__
+  postject_options options;
+  postject_options_init(&options);
+  options.macho_segment_name = "NODE_SEA";
+  const void* data =
+      postject_find_resource("NODE_EMBEDDED_DATA", &size, &options);
+#else
+  const void* data =
+      postject_find_resource("NODE_EMBEDDED_DATA", &size, nullptr);
+#endif
+
+  std::shared_ptr<BackingStore> backing_store = ArrayBuffer::NewBackingStore(
+      const_cast<void*>(static_cast<const void*>(data)),
+      size,
+      [](void* /* data */, size_t /* length */, void* /* deleter_data */) {
+        // The code cache data blob is not freed here because it is a static
+        // blob which is not allocated by the BackingStore allocator.
+      },
+      nullptr);
+  Local<ArrayBuffer> array_buffer = ArrayBuffer::New(isolate, backing_store);
+  args.GetReturnValue().Set(array_buffer);
+}
+
 void GetCodePath(const FunctionCallbackInfo<Value>& args) {
   DCHECK(IsSingleExecutable());
 
@@ -558,13 +594,15 @@ void Initialize(Local<Object> target,
             IsExperimentalSeaWarningNeeded);
   SetMethod(context, target, "getCodePath", GetCodePath);
   SetMethod(context, target, "getCodeCache", GetCodeCache);
+  SetMethod(context, target, "getEmbeddedData", GetEmbeddedData);
 }
 
 void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
   registry->Register(IsSea);
   registry->Register(IsExperimentalSeaWarningNeeded);
   registry->Register(GetCodePath);
   registry->Register(GetCodeCache);
+  registry->Register(GetEmbeddedData);
 }
 
 }  // namespace sea