Update gVisor to 20230417.0

internal/fdbased/stopfd/stopfd.go

@@ -0,0 +1,52 @@
+// 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.
+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)))
+	}
+}

internal/fdbased/stopfd/stopfd_state_autogen.go

@@ -0,0 +1,6 @@
+// automatically generated by stateify.
+
+//go:build (linux && amd64) || (linux && arm64)
+// +build linux,amd64 linux,arm64
+
+package stopfd