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/tcpip/link/stopfd/stopfd.go

@@ -0,0 +1,54 @@
+// 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.
+
+//go:build linux
+// +build linux
+
+// Package stopfd provides an type that can be used to signal the stop of a dispatcher.
+package stopfd
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/unix"
+)
+
+// StopFD is an eventfd used to signal the stop of a dispatcher.
+//
+// +stateify savable
+type StopFD struct {
+	EFD int
+}
+
+// New returns a new, initialized StopFD.
+func New() (StopFD, error) {
+	efd, err := unix.Eventfd(0, unix.EFD_NONBLOCK)
+	if err != nil {
+		return StopFD{EFD: -1}, fmt.Errorf("failed to create eventfd: %w", err)
+	}
+	return StopFD{EFD: efd}, nil
+}
+
+// Stop writes to the eventfd and notifies the dispatcher to stop. It does not
+// block.
+func (sf *StopFD) Stop() {
+	increment := []byte{1, 0, 0, 0, 0, 0, 0, 0}
+	if n, err := unix.Write(sf.EFD, increment); n != len(increment) || err != nil {
+		// There are two possible errors documented in eventfd(2) for writing:
+		// 1. We are writing 8 bytes and not 0xffffffffffffff, thus no EINVAL.
+		// 2. stop is only supposed to be called once, it can't reach the limit,
+		// thus no EAGAIN.
+		panic(fmt.Sprintf("write(EFD) = (%d, %s), want (%d, nil)", n, err, len(increment)))
+	}
+}

pkg/tcpip/link/stopfd/stopfd_state_autogen.go

@@ -0,0 +1,41 @@
+// automatically generated by stateify.
+
+//go:build linux
+// +build linux
+
+package stopfd
+
+import (
+	"context"
+
+	"github.com/sagernet/gvisor/pkg/state"
+)
+
+func (sf *StopFD) StateTypeName() string {
+	return "pkg/tcpip/link/stopfd.StopFD"
+}
+
+func (sf *StopFD) StateFields() []string {
+	return []string{
+		"EFD",
+	}
+}
+
+func (sf *StopFD) beforeSave() {}
+
+// +checklocksignore
+func (sf *StopFD) StateSave(stateSinkObject state.Sink) {
+	sf.beforeSave()
+	stateSinkObject.Save(0, &sf.EFD)
+}
+
+func (sf *StopFD) afterLoad(context.Context) {}
+
+// +checklocksignore
+func (sf *StopFD) StateLoad(ctx context.Context, stateSourceObject state.Source) {
+	stateSourceObject.Load(0, &sf.EFD)
+}
+
+func init() {
+	state.Register((*StopFD)(nil))
+}