[v16.x backport] fs: use signed types for stat data

lib/internal/fs/utils.js

@@ -12,6 +12,7 @@ const {
   NumberIsFinite,
   NumberIsInteger,
   MathMin,
+  MathRound,
   ObjectIs,
   ObjectPrototypeHasOwnProperty,
   ObjectSetPrototypeOf,
@@ -39,9 +40,9 @@ const {
 } = require('internal/errors');
 const {
   isArrayBufferView,
-  isUint8Array,
+  isBigInt64Array,
   isDate,
-  isBigUint64Array
+  isUint8Array,
 } = require('internal/util/types');
 const {
   kEmptyObject,
@@ -454,14 +455,16 @@ function nsFromTimeSpecBigInt(sec, nsec) {
   return sec * kNsPerSecBigInt + nsec;
 }
 
-// The Date constructor performs Math.floor() to the timestamp.
-// https://www.ecma-international.org/ecma-262/#sec-timeclip
+// The Date constructor performs Math.floor() on the absolute value
+// of the timestamp: https://tc39.es/ecma262/#sec-timeclip
 // Since there may be a precision loss when the timestamp is
 // converted to a floating point number, we manually round
 // the timestamp here before passing it to Date().
 // Refs: https://github.com/nodejs/node/pull/12607
+// Refs: https://github.com/nodejs/node/pull/43714
 function dateFromMs(ms) {
-  return new Date(Number(ms) + 0.5);
+  // Coercing to number, ms can be bigint
+  return new Date(MathRound(Number(ms)));
 }
 
 function BigIntStats(dev, mode, nlink, uid, gid, rdev, blksize,
@@ -526,12 +529,12 @@ Stats.prototype._checkModeProperty = function(property) {
 };
 
 /**
- * @param {Float64Array | BigUint64Array} stats
+ * @param {Float64Array | BigInt64Array} stats
  * @param {number} offset
  * @returns {BigIntStats | Stats}
  */
 function getStatsFromBinding(stats, offset = 0) {
-  if (isBigUint64Array(stats)) {
+  if (isBigInt64Array(stats)) {
     return new BigIntStats(
       stats[0 + offset], stats[1 + offset], stats[2 + offset],
       stats[3 + offset], stats[4 + offset], stats[5 + offset],

src/aliased_buffer.h

@@ -307,7 +307,7 @@ typedef AliasedBufferBase<int32_t, v8::Int32Array> AliasedInt32Array;
 typedef AliasedBufferBase<uint8_t, v8::Uint8Array> AliasedUint8Array;
 typedef AliasedBufferBase<uint32_t, v8::Uint32Array> AliasedUint32Array;
 typedef AliasedBufferBase<double, v8::Float64Array> AliasedFloat64Array;
-typedef AliasedBufferBase<uint64_t, v8::BigUint64Array> AliasedBigUint64Array;
+typedef AliasedBufferBase<int64_t, v8::BigInt64Array> AliasedBigInt64Array;
 }  // namespace node
 
 #endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

src/node_file-inl.h

@@ -86,13 +86,22 @@ template <typename NativeT, typename V8T>
 void FillStatsArray(AliasedBufferBase<NativeT, V8T>* fields,
                     const uv_stat_t* s,
                     const size_t offset) {
-#define SET_FIELD_WITH_STAT(stat_offset, stat)                               \
-  fields->SetValue(offset + static_cast<size_t>(FsStatsOffset::stat_offset), \
+#define SET_FIELD_WITH_STAT(stat_offset, stat)                                 \
+  fields->SetValue(offset + static_cast<size_t>(FsStatsOffset::stat_offset),   \
                    static_cast<NativeT>(stat))
 
-#define SET_FIELD_WITH_TIME_STAT(stat_offset, stat)                          \
-  /* NOLINTNEXTLINE(runtime/int) */                                          \
+// On win32, time is stored in uint64_t and starts from 1601-01-01.
+// libuv calculates tv_sec and tv_nsec from it and converts to signed long,
+// which causes Y2038 overflow. On the other platforms it is safe to treat
+// negative values as pre-epoch time.
+#ifdef _WIN32
+#define SET_FIELD_WITH_TIME_STAT(stat_offset, stat)                            \
+  /* NOLINTNEXTLINE(runtime/int) */                                            \
   SET_FIELD_WITH_STAT(stat_offset, static_cast<unsigned long>(stat))
+#else
+#define SET_FIELD_WITH_TIME_STAT(stat_offset, stat)                            \
+  SET_FIELD_WITH_STAT(stat_offset, static_cast<double>(stat))
+#endif  // _WIN32
 
   SET_FIELD_WITH_STAT(kDev, s->st_dev);
   SET_FIELD_WITH_STAT(kMode, s->st_mode);
@@ -233,7 +242,7 @@ FSReqBase* GetReqWrap(const v8::FunctionCallbackInfo<v8::Value>& args,
   Environment* env = binding_data->env();
   if (value->StrictEquals(env->fs_use_promises_symbol())) {
     if (use_bigint) {
-      return FSReqPromise<AliasedBigUint64Array>::New(binding_data, use_bigint);
+      return FSReqPromise<AliasedBigInt64Array>::New(binding_data, use_bigint);
     } else {
       return FSReqPromise<AliasedFloat64Array>::New(binding_data, use_bigint);
     }

src/node_file.h

@@ -18,7 +18,7 @@ class BindingData : public SnapshotableObject {
   explicit BindingData(Environment* env, v8::Local<v8::Object> wrap);
 
   AliasedFloat64Array stats_field_array;
-  AliasedBigUint64Array stats_field_bigint_array;
+  AliasedBigInt64Array stats_field_bigint_array;
 
   std::vector<BaseObjectPtr<FileHandleReadWrap>>
       file_handle_read_wrap_freelist;

test/parallel/test-fs-stat-date.mjs

@@ -0,0 +1,87 @@
+import * as common from '../common/index.mjs';
+
+// Test timestamps returned by fsPromises.stat and fs.statSync
+
+import fs from 'node:fs';
+import fsPromises from 'node:fs/promises';
+import path from 'node:path';
+import assert from 'node:assert';
+import tmpdir from '../common/tmpdir.js';
+
+// On some platforms (for example, ppc64) boundaries are tighter
+// than usual. If we catch these errors, skip corresponding test.
+const ignoredErrors = new Set(['EINVAL', 'EOVERFLOW']);
+
+tmpdir.refresh();
+const filepath = path.resolve(tmpdir.path, 'timestamp');
+
+await (await fsPromises.open(filepath, 'w')).close();
+
+// Perform a trivial check to determine if filesystem supports setting
+// and retrieving atime and mtime. If it doesn't, skip the test.
+await fsPromises.utimes(filepath, 2, 2);
+const { atimeMs, mtimeMs } = await fsPromises.stat(filepath);
+if (atimeMs !== 2000 || mtimeMs !== 2000) {
+  common.skip(`Unsupported filesystem (atime=${atimeMs}, mtime=${mtimeMs})`);
+}
+
+// Date might round down timestamp
+function closeEnough(actual, expected, margin) {
+  // On ppc64, value is rounded to seconds
+  if (process.arch === 'ppc64') {
+    margin += 1000;
+  }
+  assert.ok(Math.abs(Number(actual - expected)) < margin,
+            `expected ${expected} ± ${margin}, got ${actual}`);
+}
+
+async function runTest(atime, mtime, margin = 0) {
+  margin += Number.EPSILON;
+  try {
+    await fsPromises.utimes(filepath, new Date(atime), new Date(mtime));
+  } catch (e) {
+    if (ignoredErrors.has(e.code)) return;
+    throw e;
+  }
+
+  const stats = await fsPromises.stat(filepath);
+  closeEnough(stats.atimeMs, atime, margin);
+  closeEnough(stats.mtimeMs, mtime, margin);
+  closeEnough(stats.atime.getTime(), new Date(atime).getTime(), margin);
+  closeEnough(stats.mtime.getTime(), new Date(mtime).getTime(), margin);
+
+  const statsBigint = await fsPromises.stat(filepath, { bigint: true });
+  closeEnough(statsBigint.atimeMs, BigInt(atime), margin);
+  closeEnough(statsBigint.mtimeMs, BigInt(mtime), margin);
+  closeEnough(statsBigint.atime.getTime(), new Date(atime).getTime(), margin);
+  closeEnough(statsBigint.mtime.getTime(), new Date(mtime).getTime(), margin);
+
+  const statsSync = fs.statSync(filepath);
+  closeEnough(statsSync.atimeMs, atime, margin);
+  closeEnough(statsSync.mtimeMs, mtime, margin);
+  closeEnough(statsSync.atime.getTime(), new Date(atime).getTime(), margin);
+  closeEnough(statsSync.mtime.getTime(), new Date(mtime).getTime(), margin);
+
+  const statsSyncBigint = fs.statSync(filepath, { bigint: true });
+  closeEnough(statsSyncBigint.atimeMs, BigInt(atime), margin);
+  closeEnough(statsSyncBigint.mtimeMs, BigInt(mtime), margin);
+  closeEnough(statsSyncBigint.atime.getTime(), new Date(atime).getTime(), margin);
+  closeEnough(statsSyncBigint.mtime.getTime(), new Date(mtime).getTime(), margin);
+}
+
+// Too high/low numbers produce too different results on different platforms
+{
+  // TODO(LiviaMedeiros): investigate outdated stat time on FreeBSD.
+  // On Windows, filetime is stored and handled differently. Supporting dates
+  // after Y2038 is preferred over supporting dates before 1970-01-01.
+  if (!common.isFreeBSD && !common.isWindows) {
+    await runTest(-40691, -355, 1); // Potential precision loss on 32bit
+    await runTest(-355, -40691, 1);  // Potential precision loss on 32bit
+    await runTest(-1, -1);
+  }
+  await runTest(0, 0);
+  await runTest(1, 1);
+  await runTest(355, 40691, 1); // Precision loss on 32bit
+  await runTest(40691, 355, 1); // Precision loss on 32bit
+  await runTest(1713037251360, 1713037251360, 1); // Precision loss
+}