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/marshal/marshal.go

@@ -0,0 +1,226 @@
+// Copyright 2019 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 marshal defines the Marshallable interface for
+// serialize/deserializing go data structures to/from memory, according to the
+// Linux ABI.
+//
+// Implementations of this interface are typically automatically generated by
+// tools/go_marshal. See the go_marshal README for details.
+package marshal
+
+import (
+	"io"
+
+	"github.com/sagernet/gvisor/pkg/hostarch"
+)
+
+// CopyContext defines the memory operations required to marshal to and from
+// user memory. Typically, kernel.Task is used to provide implementations for
+// these operations.
+type CopyContext interface {
+	// CopyScratchBuffer provides a task goroutine-local scratch buffer. See
+	// kernel.CopyScratchBuffer.
+	CopyScratchBuffer(size int) []byte
+
+	// CopyOutBytes writes the contents of b to the task's memory. See
+	// kernel.CopyOutBytes.
+	CopyOutBytes(addr hostarch.Addr, b []byte) (int, error)
+
+	// CopyInBytes reads the contents of the task's memory to b. See
+	// kernel.CopyInBytes.
+	CopyInBytes(addr hostarch.Addr, b []byte) (int, error)
+}
+
+// Marshallable represents operations on a type that can be marshalled to and
+// from memory.
+//
+// go-marshal automatically generates implementations for this interface for
+// types marked as '+marshal'.
+type Marshallable interface {
+	io.WriterTo
+
+	// SizeBytes is the size of the memory representation of a type in
+	// marshalled form.
+	//
+	// SizeBytes must handle a nil receiver. Practically, this means SizeBytes
+	// cannot deference any fields on the object implementing it (but will
+	// likely make use of the type of these fields).
+	SizeBytes() int
+
+	// MarshalBytes serializes a copy of a type to dst and returns the remaining
+	// buffer.
+	// Precondition: dst must be at least SizeBytes() in length.
+	MarshalBytes(dst []byte) []byte
+
+	// UnmarshalBytes deserializes a type from src and returns the remaining
+	// buffer.
+	// Precondition: src must be at least SizeBytes() in length.
+	UnmarshalBytes(src []byte) []byte
+
+	// Packed returns true if the marshalled size of the type is the same as the
+	// size it occupies in memory. This happens when the type has no fields
+	// starting at unaligned addresses (should always be true by default for ABI
+	// structs, verified by automatically generated tests when using
+	// go_marshal), and has no fields marked `marshal:"unaligned"`.
+	//
+	// Packed must return the same result for all possible values of the type
+	// implementing it. Violating this constraint implies the type doesn't have
+	// a static memory layout, and will lead to memory corruption.
+	// Go-marshal-generated code reuses the result of Packed for multiple values
+	// of the same type.
+	Packed() bool
+
+	// MarshalUnsafe serializes a type by bulk copying its in-memory
+	// representation to the dst buffer. This is only safe to do when the type
+	// has no implicit padding, see Marshallable.Packed. When Packed would
+	// return false, MarshalUnsafe should fall back to the safer but slower
+	// MarshalBytes.
+	// Precondition: dst must be at least SizeBytes() in length.
+	MarshalUnsafe(dst []byte) []byte
+
+	// UnmarshalUnsafe deserializes a type by directly copying to the underlying
+	// memory allocated for the object by the runtime.
+	//
+	// This allows much faster unmarshalling of types which have no implicit
+	// padding, see Marshallable.Packed. When Packed would return false,
+	// UnmarshalUnsafe should fall back to the safer but slower unmarshal
+	// mechanism implemented in UnmarshalBytes.
+	// Precondition: src must be at least SizeBytes() in length.
+	UnmarshalUnsafe(src []byte) []byte
+
+	// CopyIn deserializes a Marshallable type from a task's memory. This may
+	// only be called from a task goroutine. This is more efficient than calling
+	// UnmarshalUnsafe on Marshallable.Packed types, as the type being
+	// marshalled does not escape. The implementation should avoid creating
+	// extra copies in memory by directly deserializing to the object's
+	// underlying memory.
+	//
+	// If the copy-in from the task memory is only partially successful, CopyIn
+	// should still attempt to deserialize as much data as possible. See comment
+	// for UnmarshalBytes.
+	CopyIn(cc CopyContext, addr hostarch.Addr) (int, error)
+
+	// CopyInN is like CopyIn, but explicitly requests a partial
+	// copy-in. Note that this may yield unexpected results for non-packed
+	// types and the caller may only want to allow this for packed types. See
+	// comment on UnmarshalBytes.
+	//
+	// The limit must be less than or equal to SizeBytes().
+	CopyInN(cc CopyContext, addr hostarch.Addr, limit int) (int, error)
+
+	// CopyOut serializes a Marshallable type to a task's memory. This may only
+	// be called from a task goroutine. This is more efficient than calling
+	// MarshalUnsafe on Marshallable.Packed types, as the type being serialized
+	// does not escape. The implementation should avoid creating extra copies in
+	// memory by directly serializing from the object's underlying memory.
+	//
+	// The copy-out to the task memory may be partially successful, in which
+	// case CopyOut returns how much data was serialized. See comment for
+	// MarshalBytes for implications.
+	CopyOut(cc CopyContext, addr hostarch.Addr) (int, error)
+
+	// CopyOutN is like CopyOut, but explicitly requests a partial
+	// copy-out. Note that this may yield unexpected results for non-packed
+	// types and the caller may only want to allow this for packed types. See
+	// comment on MarshalBytes.
+	//
+	// The limit must be less than or equal to SizeBytes().
+	CopyOutN(cc CopyContext, addr hostarch.Addr, limit int) (int, error)
+}
+
+// CheckedMarshallable represents operations on a type that can be marshalled
+// to and from memory and additionally does bound checking.
+type CheckedMarshallable interface {
+	// CheckedMarshal is the same as Marshallable.MarshalUnsafe but without the
+	// precondition that dst must at least have some appropriate length. Similar
+	// to Marshallable.MarshalBytes, it returns a shifted slice according to how
+	// much data is consumed. Additionally it returns a bool indicating whether
+	// marshalling was successful. Unsuccessful marshalling doesn't consume any
+	// data.
+	CheckedMarshal(dst []byte) ([]byte, bool)
+
+	// CheckedUnmarshal is the same as Marshallable.UmarshalUnsafe but without
+	// the precondition that src must at least have some appropriate length.
+	// Similar to Marshallable.UnmarshalBytes, it returns a shifted slice
+	// according to how much data is consumed. Additionally it returns a bool
+	// indicating whether marshalling was successful. Unsuccessful marshalling
+	// doesn't consume any data.
+	CheckedUnmarshal(src []byte) ([]byte, bool)
+}
+
+// go-marshal generates additional functions for a type based on additional
+// clauses to the +marshal directive. They are documented below.
+//
+// Slice API
+// =========
+//
+// Adding a "slice" clause to the +marshal directive for structs or newtypes on
+// primitives like this:
+//
+// // +marshal slice:FooSlice
+// type Foo struct { ... }
+//
+// Generates four additional functions for marshalling slices of Foos like this:
+//
+// // MarshalUnsafeFooSlice is like Foo.MarshalUnsafe, buf for a []Foo. It
+// // might be more efficient that repeatedly calling Foo.MarshalUnsafe
+// // over a []Foo in a loop if the type is Packed.
+// // Preconditions: dst must be at least len(src)*Foo.SizeBytes() in length.
+// func MarshalUnsafeFooSlice(src []Foo, dst []byte) []byte { ... }
+//
+// // UnmarshalUnsafeFooSlice is like Foo.UnmarshalUnsafe, buf for a []Foo. It
+// // might be more efficient that repeatedly calling Foo.UnmarshalUnsafe
+// // over a []Foo in a loop if the type is Packed.
+// // Preconditions: src must be at least len(dst)*Foo.SizeBytes() in length.
+// func UnmarshalUnsafeFooSlice(dst []Foo, src []byte) []byte { ... }
+//
+// // CopyFooSliceIn copies in a slice of Foo objects from the task's memory.
+// func CopyFooSliceIn(cc marshal.CopyContext, addr hostarch.Addr, dst []Foo) (int, error) { ... }
+//
+// // CopyFooSliceIn copies out a slice of Foo objects to the task's memory.
+// func CopyFooSliceOut(cc marshal.CopyContext, addr hostarch.Addr, src []Foo) (int, error) { ... }
+//
+// The name of the functions are of the format "Copy%sIn" and "Copy%sOut", where
+// %s is the first argument to the slice clause. This directive is not supported
+// for newtypes on arrays.
+//
+// Note: Partial copies are not supported for Slice API UnmarshalUnsafe and
+// MarshalUnsafe.
+//
+// The slice clause also takes an optional second argument, which must be the
+// value "inner":
+//
+// // +marshal slice:Int32Slice:inner
+// type Int32 int32
+//
+// This is only valid on newtypes on primitives, and causes the generated
+// functions to accept slices of the inner type instead:
+//
+// func CopyInt32SliceIn(cc marshal.CopyContext, addr hostarch.Addr, dst []int32) (int, error) { ... }
+//
+// Without "inner", they would instead be:
+//
+// func CopyInt32SliceIn(cc marshal.CopyContext, addr hostarch.Addr, dst []Int32) (int, error) { ... }
+//
+// This may help avoid a cast depending on how the generated functions are used.
+//
+// Bound Checking
+// ==============
+//
+// Some users might want to do bound checking on marshal and unmarshal. This is
+// is useful when the user does not control the buffer size. To prevent
+// repeated bound checking code around Marshallable, users can add a
+// "boundCheck" clause to the +marshal directive. go_marshal will generate the
+// CheckedMarshallable interface methods on the type.

pkg/marshal/marshal_state_autogen.go

@@ -0,0 +1,3 @@
+// automatically generated by stateify.
+
+package marshal

pkg/marshal/primitive/primitive.go

@@ -0,0 +1,405 @@
+// Copyright 2020 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 primitive defines marshal.Marshallable implementations for primitive
+// types.
+package primitive
+
+import (
+	"io"
+
+	"github.com/sagernet/gvisor/pkg/hostarch"
+	"github.com/sagernet/gvisor/pkg/marshal"
+)
+
+// Int8 is a marshal.Marshallable implementation for int8.
+//
+// +marshal boundCheck slice:Int8Slice:inner
+type Int8 int8
+
+// Uint8 is a marshal.Marshallable implementation for uint8.
+//
+// +marshal boundCheck slice:Uint8Slice:inner
+type Uint8 uint8
+
+// Int16 is a marshal.Marshallable implementation for int16.
+//
+// +marshal boundCheck slice:Int16Slice:inner
+type Int16 int16
+
+// Uint16 is a marshal.Marshallable implementation for uint16.
+//
+// +marshal boundCheck slice:Uint16Slice:inner
+type Uint16 uint16
+
+// Int32 is a marshal.Marshallable implementation for int32.
+//
+// +marshal boundCheck slice:Int32Slice:inner
+type Int32 int32
+
+// Uint32 is a marshal.Marshallable implementation for uint32.
+//
+// +marshal boundCheck slice:Uint32Slice:inner
+type Uint32 uint32
+
+// Int64 is a marshal.Marshallable implementation for int64.
+//
+// +marshal boundCheck slice:Int64Slice:inner
+type Int64 int64
+
+// Uint64 is a marshal.Marshallable implementation for uint64.
+//
+// +marshal boundCheck slice:Uint64Slice:inner
+type Uint64 uint64
+
+// ByteSlice is a marshal.Marshallable implementation for []byte.
+// This is a convenience wrapper around a dynamically sized type, and can't be
+// embedded in other marshallable types because it breaks assumptions made by
+// go-marshal internals. It violates the "no dynamically-sized types"
+// constraint of the go-marshal library.
+type ByteSlice []byte
+
+// SizeBytes implements marshal.Marshallable.SizeBytes.
+func (b *ByteSlice) SizeBytes() int {
+	return len(*b)
+}
+
+// MarshalBytes implements marshal.Marshallable.MarshalBytes.
+func (b *ByteSlice) MarshalBytes(dst []byte) []byte {
+	return dst[copy(dst, *b):]
+}
+
+// UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes.
+func (b *ByteSlice) UnmarshalBytes(src []byte) []byte {
+	return src[copy(*b, src):]
+}
+
+// Packed implements marshal.Marshallable.Packed.
+func (b *ByteSlice) Packed() bool {
+	return false
+}
+
+// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
+func (b *ByteSlice) MarshalUnsafe(dst []byte) []byte {
+	return b.MarshalBytes(dst)
+}
+
+// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
+func (b *ByteSlice) UnmarshalUnsafe(src []byte) []byte {
+	return b.UnmarshalBytes(src)
+}
+
+// CopyIn implements marshal.Marshallable.CopyIn.
+func (b *ByteSlice) CopyIn(cc marshal.CopyContext, addr hostarch.Addr) (int, error) {
+	return cc.CopyInBytes(addr, *b)
+}
+
+// CopyInN implements marshal.Marshallable.CopyInN.
+func (b *ByteSlice) CopyInN(cc marshal.CopyContext, addr hostarch.Addr, limit int) (int, error) {
+	return cc.CopyInBytes(addr, (*b)[:limit])
+}
+
+// CopyOut implements marshal.Marshallable.CopyOut.
+func (b *ByteSlice) CopyOut(cc marshal.CopyContext, addr hostarch.Addr) (int, error) {
+	return cc.CopyOutBytes(addr, *b)
+}
+
+// CopyOutN implements marshal.Marshallable.CopyOutN.
+func (b *ByteSlice) CopyOutN(cc marshal.CopyContext, addr hostarch.Addr, limit int) (int, error) {
+	return cc.CopyOutBytes(addr, (*b)[:limit])
+}
+
+// WriteTo implements io.WriterTo.WriteTo.
+func (b *ByteSlice) WriteTo(w io.Writer) (int64, error) {
+	n, err := w.Write(*b)
+	return int64(n), err
+}
+
+var _ marshal.Marshallable = (*ByteSlice)(nil)
+
+// The following set of functions are convenient shorthands for wrapping a
+// built-in type in a marshallable primitive type. For example:
+//
+// func useMarshallable(m marshal.Marshallable) { ... }
+//
+// // Compare:
+//
+// buf = []byte{...}
+// // useMarshallable(&primitive.ByteSlice(buf)) // Not allowed, can't address temp value.
+// bufP := primitive.ByteSlice(buf)
+// useMarshallable(&bufP)
+//
+// // Vs:
+//
+// useMarshallable(AsByteSlice(buf))
+//
+// Note that the argument to these function escapes, so avoid using them on very
+// hot code paths. But generally if a function accepts an interface as an
+// argument, the argument escapes anyways.
+
+// AllocateInt8 returns x as a marshallable.
+func AllocateInt8(x int8) marshal.Marshallable {
+	p := Int8(x)
+	return &p
+}
+
+// AllocateUint8 returns x as a marshallable.
+func AllocateUint8(x uint8) marshal.Marshallable {
+	p := Uint8(x)
+	return &p
+}
+
+// AllocateInt16 returns x as a marshallable.
+func AllocateInt16(x int16) marshal.Marshallable {
+	p := Int16(x)
+	return &p
+}
+
+// AllocateUint16 returns x as a marshallable.
+func AllocateUint16(x uint16) marshal.Marshallable {
+	p := Uint16(x)
+	return &p
+}
+
+// AllocateInt32 returns x as a marshallable.
+func AllocateInt32(x int32) marshal.Marshallable {
+	p := Int32(x)
+	return &p
+}
+
+// AllocateUint32 returns x as a marshallable.
+func AllocateUint32(x uint32) marshal.Marshallable {
+	p := Uint32(x)
+	return &p
+}
+
+// AllocateInt64 returns x as a marshallable.
+func AllocateInt64(x int64) marshal.Marshallable {
+	p := Int64(x)
+	return &p
+}
+
+// AllocateUint64 returns x as a marshallable.
+func AllocateUint64(x uint64) marshal.Marshallable {
+	p := Uint64(x)
+	return &p
+}
+
+// AsByteSlice returns b as a marshallable. Note that this allocates a new slice
+// header, but does not copy the slice contents.
+func AsByteSlice(b []byte) marshal.Marshallable {
+	bs := ByteSlice(b)
+	return &bs
+}
+
+// Below, we define some convenience functions for marshalling primitive types
+// using the newtypes above, without requiring superfluous casts.
+
+// 8-bit integers
+
+// CopyInt8In is a convenient wrapper for copying in an int8 from the task's
+// memory.
+func CopyInt8In(cc marshal.CopyContext, addr hostarch.Addr, dst *int8) (int, error) {
+	var buf Int8
+	n, err := buf.CopyIn(cc, addr)
+	if err != nil {
+		return n, err
+	}
+	*dst = int8(buf)
+	return n, nil
+}
+
+// CopyInt8Out is a convenient wrapper for copying out an int8 to the task's
+// memory.
+func CopyInt8Out(cc marshal.CopyContext, addr hostarch.Addr, src int8) (int, error) {
+	srcP := Int8(src)
+	return srcP.CopyOut(cc, addr)
+}
+
+// CopyUint8In is a convenient wrapper for copying in a uint8 from the task's
+// memory.
+func CopyUint8In(cc marshal.CopyContext, addr hostarch.Addr, dst *uint8) (int, error) {
+	var buf Uint8
+	n, err := buf.CopyIn(cc, addr)
+	if err != nil {
+		return n, err
+	}
+	*dst = uint8(buf)
+	return n, nil
+}
+
+// CopyUint8Out is a convenient wrapper for copying out a uint8 to the task's
+// memory.
+func CopyUint8Out(cc marshal.CopyContext, addr hostarch.Addr, src uint8) (int, error) {
+	srcP := Uint8(src)
+	return srcP.CopyOut(cc, addr)
+}
+
+// 16-bit integers
+
+// CopyInt16In is a convenient wrapper for copying in an int16 from the task's
+// memory.
+func CopyInt16In(cc marshal.CopyContext, addr hostarch.Addr, dst *int16) (int, error) {
+	var buf Int16
+	n, err := buf.CopyIn(cc, addr)
+	if err != nil {
+		return n, err
+	}
+	*dst = int16(buf)
+	return n, nil
+}
+
+// CopyInt16Out is a convenient wrapper for copying out an int16 to the task's
+// memory.
+func CopyInt16Out(cc marshal.CopyContext, addr hostarch.Addr, src int16) (int, error) {
+	srcP := Int16(src)
+	return srcP.CopyOut(cc, addr)
+}
+
+// CopyUint16In is a convenient wrapper for copying in a uint16 from the task's
+// memory.
+func CopyUint16In(cc marshal.CopyContext, addr hostarch.Addr, dst *uint16) (int, error) {
+	var buf Uint16
+	n, err := buf.CopyIn(cc, addr)
+	if err != nil {
+		return n, err
+	}
+	*dst = uint16(buf)
+	return n, nil
+}
+
+// CopyUint16Out is a convenient wrapper for copying out a uint16 to the task's
+// memory.
+func CopyUint16Out(cc marshal.CopyContext, addr hostarch.Addr, src uint16) (int, error) {
+	srcP := Uint16(src)
+	return srcP.CopyOut(cc, addr)
+}
+
+// 32-bit integers
+
+// CopyInt32In is a convenient wrapper for copying in an int32 from the task's
+// memory.
+func CopyInt32In(cc marshal.CopyContext, addr hostarch.Addr, dst *int32) (int, error) {
+	var buf Int32
+	n, err := buf.CopyIn(cc, addr)
+	if err != nil {
+		return n, err
+	}
+	*dst = int32(buf)
+	return n, nil
+}
+
+// CopyInt32Out is a convenient wrapper for copying out an int32 to the task's
+// memory.
+func CopyInt32Out(cc marshal.CopyContext, addr hostarch.Addr, src int32) (int, error) {
+	srcP := Int32(src)
+	return srcP.CopyOut(cc, addr)
+}
+
+// CopyUint32In is a convenient wrapper for copying in a uint32 from the task's
+// memory.
+func CopyUint32In(cc marshal.CopyContext, addr hostarch.Addr, dst *uint32) (int, error) {
+	var buf Uint32
+	n, err := buf.CopyIn(cc, addr)
+	if err != nil {
+		return n, err
+	}
+	*dst = uint32(buf)
+	return n, nil
+}
+
+// CopyUint32Out is a convenient wrapper for copying out a uint32 to the task's
+// memory.
+func CopyUint32Out(cc marshal.CopyContext, addr hostarch.Addr, src uint32) (int, error) {
+	srcP := Uint32(src)
+	return srcP.CopyOut(cc, addr)
+}
+
+// 64-bit integers
+
+// CopyInt64In is a convenient wrapper for copying in an int64 from the task's
+// memory.
+func CopyInt64In(cc marshal.CopyContext, addr hostarch.Addr, dst *int64) (int, error) {
+	var buf Int64
+	n, err := buf.CopyIn(cc, addr)
+	if err != nil {
+		return n, err
+	}
+	*dst = int64(buf)
+	return n, nil
+}
+
+// CopyInt64Out is a convenient wrapper for copying out an int64 to the task's
+// memory.
+func CopyInt64Out(cc marshal.CopyContext, addr hostarch.Addr, src int64) (int, error) {
+	srcP := Int64(src)
+	return srcP.CopyOut(cc, addr)
+}
+
+// CopyUint64In is a convenient wrapper for copying in a uint64 from the task's
+// memory.
+func CopyUint64In(cc marshal.CopyContext, addr hostarch.Addr, dst *uint64) (int, error) {
+	var buf Uint64
+	n, err := buf.CopyIn(cc, addr)
+	if err != nil {
+		return n, err
+	}
+	*dst = uint64(buf)
+	return n, nil
+}
+
+// CopyUint64Out is a convenient wrapper for copying out a uint64 to the task's
+// memory.
+func CopyUint64Out(cc marshal.CopyContext, addr hostarch.Addr, src uint64) (int, error) {
+	srcP := Uint64(src)
+	return srcP.CopyOut(cc, addr)
+}
+
+// CopyByteSliceIn is a convenient wrapper for copying in a []byte from the
+// task's memory.
+func CopyByteSliceIn(cc marshal.CopyContext, addr hostarch.Addr, dst *[]byte) (int, error) {
+	var buf ByteSlice
+	n, err := buf.CopyIn(cc, addr)
+	if err != nil {
+		return n, err
+	}
+	*dst = []byte(buf)
+	return n, nil
+}
+
+// CopyByteSliceOut is a convenient wrapper for copying out a []byte to the
+// task's memory.
+func CopyByteSliceOut(cc marshal.CopyContext, addr hostarch.Addr, src []byte) (int, error) {
+	srcP := ByteSlice(src)
+	return srcP.CopyOut(cc, addr)
+}
+
+// CopyStringIn is a convenient wrapper for copying in a string from the
+// task's memory.
+func CopyStringIn(cc marshal.CopyContext, addr hostarch.Addr, dst *string) (int, error) {
+	var buf ByteSlice
+	n, err := buf.CopyIn(cc, addr)
+	if err != nil {
+		return n, err
+	}
+	*dst = string(buf)
+	return n, nil
+}
+
+// CopyStringOut is a convenient wrapper for copying out a string to the task's
+// memory.
+func CopyStringOut(cc marshal.CopyContext, addr hostarch.Addr, src string) (int, error) {
+	srcP := ByteSlice(src)
+	return srcP.CopyOut(cc, addr)
+}

pkg/marshal/primitive/primitive_state_autogen.go

@@ -0,0 +1,3 @@
+// automatically generated by stateify.
+
+package primitive

pkg/marshal/util.go

@@ -0,0 +1,44 @@
+// Copyright 2020 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 marshal
+
+// Marshal returns the serialized contents of m in a newly allocated
+// byte slice.
+func Marshal(m Marshallable) []byte {
+	buf := make([]byte, m.SizeBytes())
+	m.MarshalUnsafe(buf)
+	return buf
+}
+
+// MarshalAll returns the serialized contents of all ms in a newly allocated
+// byte slice.
+func MarshalAll(ms []Marshallable) []byte {
+	buf := make([]byte, TotalSize(ms))
+	var written int
+	for _, m := range ms {
+		m.MarshalUnsafe(buf[written:])
+		written += m.SizeBytes()
+	}
+	return buf
+}
+
+// TotalSize returns the total size of all ms.
+func TotalSize(ms []Marshallable) int {
+	var size int
+	for _, m := range ms {
+		size += m.SizeBytes()
+	}
+	return size
+}