fs: throw errors from fs.ftruncateSync in JS

PR-URL: https://github.com/nodejs/node/pull/18348
Refs: https://github.com/nodejs/node/issues/18106
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/fs.js

@@ -995,7 +995,11 @@ fs.ftruncateSync = function(fd, len = 0) {
   validateUint32(fd, 'fd');
   validateLen(len);
   len = Math.max(0, len);
-  return binding.ftruncate(fd, len);
+  const ctx = {};
+  binding.ftruncate(fd, len, undefined, ctx);
+  if (ctx.errno !== undefined) {
+    throw new errors.uvException(ctx);
+  }
 };
 
 fs.rmdir = function(path, callback) {

src/node_file.cc

@@ -711,18 +711,24 @@ static void Rename(const FunctionCallbackInfo<Value>& args) {
 static void FTruncate(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
 
+  const int argc = args.Length();
+  CHECK_GE(argc, 3);
+
   CHECK(args[0]->IsInt32());
+  const int fd = args[0].As<Int32>()->Value();
+
   CHECK(args[1]->IsNumber());
+  const int64_t len = args[1].As<Integer>()->Value();
 
-  int fd = args[0]->Int32Value();
+  if (args[2]->IsObject()) {  // ftruncate(fd, len, req)
-  const int64_t len = args[1]->IntegerValue();
+    CHECK_EQ(argc, 3);
-
-  if (args[2]->IsObject()) {
-    CHECK_EQ(args.Length(), 3);
     AsyncCall(env, args, "ftruncate", UTF8, AfterNoArgs,
               uv_fs_ftruncate, fd, len);
-  } else {
+  } else {  // ftruncate(fd, len, undefined, ctx)
-    SYNC_CALL(ftruncate, 0, fd, len)
+    CHECK_EQ(argc, 4);
+    fs_req_wrap req_wrap;
+    SyncCall(env, args[3], &req_wrap, "ftruncate",
+             uv_fs_ftruncate, fd, len);
   }
 }
 

test/parallel/test-fs-error-messages.js

@@ -455,3 +455,30 @@ function re(literals, ...values) {
     validateError
   );
 }
+
+// ftruncate
+{
+  const validateError = (err) => {
+    assert.strictEqual(err.syscall, 'ftruncate');
+    // Could be EBADF or EINVAL, depending on the platform
+    if (err.code === 'EBADF') {
+      assert.strictEqual(err.message, 'EBADF: bad file descriptor, ftruncate');
+      assert.strictEqual(err.errno, uv.UV_EBADF);
+    } else {
+      assert.strictEqual(err.message, 'EINVAL: invalid argument, ftruncate');
+      assert.strictEqual(err.errno, uv.UV_EINVAL);
+      assert.strictEqual(err.code, 'EINVAL');
+    }
+    return true;
+  };
+
+  const fd = fs.openSync(existingFile, 'r');
+  fs.closeSync(fd);
+
+  fs.ftruncate(fd, 4, common.mustCall(validateError));
+
+  assert.throws(
+    () => fs.ftruncateSync(fd, 4),
+    validateError
+  );
+}