fs: throw errors from fs.linkSync in JS

PR-URL: #18348
Refs: #18106
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: joyeecheung

lib/fs.js

@@ -1280,8 +1280,15 @@ fs.linkSync = function(existingPath, newPath) {
   nullCheck(newPath);
   validatePath(existingPath, 'existingPath');
   validatePath(newPath, 'newPath');
-  return binding.link(pathModule.toNamespacedPath(existingPath),
-                      pathModule.toNamespacedPath(newPath));
+
+  const ctx = { path: existingPath, dest: newPath };
+  const result = binding.link(pathModule.toNamespacedPath(existingPath),
+                              pathModule.toNamespacedPath(newPath),
+                              undefined, ctx);
+  if (ctx.errno !== undefined) {
+    throw new errors.uvException(ctx);
+  }
+  return result;
 };
 
 fs.unlink = function(path, callback) {

src/node_file.cc

@@ -624,7 +624,8 @@ static void Symlink(const FunctionCallbackInfo<Value>& args) {
 static void Link(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
 
-  CHECK_GE(args.Length(), 2);
+  int argc = args.Length();
+  CHECK_GE(argc, 3);
 
   BufferValue src(env->isolate(), args[0]);
   CHECK_NE(*src, nullptr);
@@ -633,11 +634,14 @@ static void Link(const FunctionCallbackInfo<Value>& args) {
   CHECK_NE(*dest, nullptr);
 
   if (args[2]->IsObject()) {  // link(src, dest, req)
-    CHECK_EQ(args.Length(), 3);
+    CHECK_EQ(argc, 3);
     AsyncDestCall(env, args, "link", *dest, dest.length(), UTF8,
                   AfterNoArgs, uv_fs_link, *src, *dest);
-  } else {  // link(src, dest)
-    SYNC_DEST_CALL(link, *src, *dest, *src, *dest)
+  } else {  // link(src, dest, undefined, ctx)
+    CHECK_EQ(argc, 4);
+    fs_req_wrap req_wrap;
+    SyncCall(env, args[3], &req_wrap, "link",
+             uv_fs_link, *src, *dest);
   }
 }