2019-09-09 20:35:30 +00:00
|
|
|
// 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
|
|
|
|
|
2020-02-14 00:31:33 +00:00
|
|
|
import (
|
2020-02-15 02:31:55 +00:00
|
|
|
"io"
|
|
|
|
|
2020-02-14 00:31:33 +00:00
|
|
|
"gvisor.dev/gvisor/pkg/usermem"
|
|
|
|
)
|
|
|
|
|
|
|
|
// Task provides a subset of kernel.Task, used in marshalling. We don't import
|
|
|
|
// the kernel package directly to avoid circular dependency.
|
|
|
|
type Task 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 usermem.Addr, b []byte) (int, error)
|
|
|
|
|
|
|
|
// CopyInBytes reads the contents of the task's memory to b. See
|
|
|
|
// kernel.CopyInBytes.
|
|
|
|
CopyInBytes(addr usermem.Addr, b []byte) (int, error)
|
|
|
|
}
|
|
|
|
|
2019-09-09 20:35:30 +00:00
|
|
|
// Marshallable represents a type that can be marshalled to and from memory.
|
|
|
|
type Marshallable interface {
|
2020-02-15 02:31:55 +00:00
|
|
|
io.WriterTo
|
|
|
|
|
2019-09-09 20:35:30 +00:00
|
|
|
// SizeBytes is the size of the memory representation of a type in
|
|
|
|
// marshalled form.
|
|
|
|
SizeBytes() int
|
|
|
|
|
|
|
|
// MarshalBytes serializes a copy of a type to dst. dst must be at least
|
|
|
|
// SizeBytes() long.
|
|
|
|
MarshalBytes(dst []byte)
|
|
|
|
|
|
|
|
// UnmarshalBytes deserializes a type from src. src must be at least
|
|
|
|
// SizeBytes() long.
|
|
|
|
UnmarshalBytes(src []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() 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.
|
|
|
|
MarshalUnsafe(dst []byte)
|
|
|
|
|
2020-02-14 00:31:33 +00:00
|
|
|
// UnmarshalUnsafe deserializes a type by directly copying to the underlying
|
|
|
|
// memory allocated for the object by the runtime.
|
2019-09-09 20:35:30 +00:00
|
|
|
//
|
|
|
|
// 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
|
2020-02-14 00:31:33 +00:00
|
|
|
// mechanism implemented in UnmarshalBytes.
|
2019-09-09 20:35:30 +00:00
|
|
|
UnmarshalUnsafe(src []byte)
|
2020-02-14 00:31:33 +00:00
|
|
|
|
|
|
|
// 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.
|
|
|
|
CopyIn(task Task, addr usermem.Addr) (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.
|
|
|
|
CopyOut(task Task, addr usermem.Addr) (int, error)
|
2019-09-09 20:35:30 +00:00
|
|
|
}
|