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_unsafe.go

@@ -0,0 +1,121 @@
+// Copyright 2018 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
+
+import (
+	"unsafe"
+
+	"github.com/sagernet/gvisor/pkg/syserr"
+	"golang.org/x/sys/unix"
+)
+
+// UnixDirentMaxSize is the maximum size of unix.Dirent in bytes.
+var UnixDirentMaxSize = int(unsafe.Sizeof(unix.Dirent{}))
+
+// Utimensat is a convenience wrapper to make the utimensat(2) syscall. It
+// additionally handles empty name.
+func Utimensat(dirFd int, name string, times [2]unix.Timespec, flags int) error {
+	// utimensat(2) doesn't accept empty name, instead name must be nil to make it
+	// operate directly on 'dirFd' unlike other *at syscalls.
+	var namePtr unsafe.Pointer
+	if name != "" {
+		nameBytes, err := unix.BytePtrFromString(name)
+		if err != nil {
+			return err
+		}
+		namePtr = unsafe.Pointer(nameBytes)
+	}
+
+	timesPtr := unsafe.Pointer(&times[0])
+
+	if _, _, errno := unix.Syscall6(
+		unix.SYS_UTIMENSAT,
+		uintptr(dirFd),
+		uintptr(namePtr),
+		uintptr(timesPtr),
+		uintptr(flags),
+		0,
+		0); errno != 0 {
+		return syserr.FromHost(errno).ToError()
+	}
+	return nil
+}
+
+// RenameAt is a convenience wrapper to make the renameat(2) syscall. It
+// additionally handles empty names.
+func RenameAt(oldDirFD int, oldName string, newDirFD int, newName string) error {
+	var oldNamePtr unsafe.Pointer
+	if oldName != "" {
+		nameBytes, err := unix.BytePtrFromString(oldName)
+		if err != nil {
+			return err
+		}
+		oldNamePtr = unsafe.Pointer(nameBytes)
+	}
+	var newNamePtr unsafe.Pointer
+	if newName != "" {
+		nameBytes, err := unix.BytePtrFromString(newName)
+		if err != nil {
+			return err
+		}
+		newNamePtr = unsafe.Pointer(nameBytes)
+	}
+
+	if _, _, errno := unix.Syscall6(
+		unix.SYS_RENAMEAT,
+		uintptr(oldDirFD),
+		uintptr(oldNamePtr),
+		uintptr(newDirFD),
+		uintptr(newNamePtr),
+		0,
+		0); errno != 0 {
+		return syserr.FromHost(errno).ToError()
+	}
+	return nil
+}
+
+// ParseDirents parses dirents from buf. buf must have been populated by
+// getdents64(2) syscall. It calls the handleDirent callback for each dirent.
+func ParseDirents(buf []byte, handleDirent DirentHandler) {
+	for len(buf) > 0 {
+		// Interpret the buf populated by unix.Getdents as unix.Dirent.
+		dirent := *(*unix.Dirent)(unsafe.Pointer(&buf[0]))
+
+		// Advance buf for the next dirent.
+		buf = buf[dirent.Reclen:]
+
+		// Extracting the name is pretty tedious...
+		var nameBuf [unix.NAME_MAX]byte
+		var nameLen int
+		for i := 0; i < len(dirent.Name); i++ {
+			// The name is null terminated.
+			if dirent.Name[i] == 0 {
+				nameLen = i
+				break
+			}
+			nameBuf[i] = byte(dirent.Name[i])
+		}
+		name := string(nameBuf[:nameLen])
+
+		// Skip `.` and `..` entries. It is anyways ignored by the client. We also
+		// don't want to leak information about `..`.
+		if name == "." || name == ".." {
+			continue
+		}
+
+		// Deliver results to caller.
+		handleDirent(dirent.Ino, dirent.Off, dirent.Type, name, dirent.Reclen)
+	}
+}