gvisor/pkg/sentry/fs/restore.go

79 lines
2.3 KiB
Go

// 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 fs
import (
"sync"
)
// RestoreEnvironment is the restore environment for file systems. It consists
// of things that change across save and restore and therefore cannot be saved
// in the object graph.
type RestoreEnvironment struct {
// MountSources maps Filesystem.Name() to mount arguments.
MountSources map[string][]MountArgs
// ValidateFileSize indicates file size should not change across S/R.
ValidateFileSize bool
// ValidateFileTimestamp indicates file modification timestamp should
// not change across S/R.
ValidateFileTimestamp bool
}
// MountArgs holds arguments to Mount.
type MountArgs struct {
// Dev corresponds to the devname argumnent of Mount.
Dev string
// Flags corresponds to the flags argument of Mount.
Flags MountSourceFlags
// DataString corresponds to the data argument of Mount.
DataString string
// DataObj corresponds to the data interface argument of Mount.
DataObj interface{}
}
// restoreEnv holds the fs package global RestoreEnvironment.
var restoreEnv = struct {
mu sync.Mutex
env RestoreEnvironment
set bool
}{}
// SetRestoreEnvironment sets the RestoreEnvironment. Must be called before
// state.Load and only once.
func SetRestoreEnvironment(r RestoreEnvironment) {
restoreEnv.mu.Lock()
defer restoreEnv.mu.Unlock()
if restoreEnv.set {
panic("RestoreEnvironment may only be set once")
}
restoreEnv.env = r
restoreEnv.set = true
}
// CurrentRestoreEnvironment returns the current, read-only RestoreEnvironment.
// If no RestoreEnvironment was ever set, returns (_, false).
func CurrentRestoreEnvironment() (RestoreEnvironment, bool) {
restoreEnv.mu.Lock()
defer restoreEnv.mu.Unlock()
e := restoreEnv.env
set := restoreEnv.set
return e, set
}