snapshot: sagernet/gvisor v0.0.0-20250811.0-sing-box-mod.1

Содержимое пина, зафиксированного в go.mod sing-box-lx, одним коммитом
без истории. Полная история SagerNet/gvisor — 1.45 ГБ и клонируется в
каждой CI-джобе; наша дельта — одна вставка в одну функцию, история для
неё не нужна.

Module path github.com/sagernet/gvisor сохранён намеренно: на него
опирается replace-директива суперпроекта.

Патч поверх — отдельным коммитом, чтобы дельта читалась одним git show
и переносилась на новый пин копированием.

SPECS/TASKS/048-GVISOR_HANDSHAKE_NIL_CRASH

pkg/fsutil/fsutil.go

@@ -0,0 +1,48 @@
+// Copyright 2022 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package fsutil contains filesystem utilities that can be shared between the
+// sentry and other sandbox components.
+package fsutil
+
+import "golang.org/x/sys/unix"
+
+// DirentHandler is a function that handles a dirent.
+type DirentHandler func(ino uint64, off int64, ftype uint8, name string, reclen uint16)
+
+// ForEachDirent retrieves all dirents from dirfd using getdents64(2) and
+// invokes handleDirent on them.
+func ForEachDirent(dirfd int, handleDirent DirentHandler) error {
+	var direntsBuf [8192]byte
+	for {
+		n, err := unix.Getdents(dirfd, direntsBuf[:])
+		if err != nil {
+			return err
+		}
+		if n <= 0 {
+			return nil
+		}
+		ParseDirents(direntsBuf[:n], handleDirent)
+	}
+}
+
+// DirentNames retrieves all dirents from dirfd using getdents64(2) and returns
+// all the recorded dirent names.
+func DirentNames(dirfd int) ([]string, error) {
+	var names []string
+	err := ForEachDirent(dirfd, func(_ uint64, _ int64, _ uint8, name string, _ uint16) {
+		names = append(names, name)
+	})
+	return names, err
+}