119 lines
3.1 KiB
Go
119 lines
3.1 KiB
Go
// Copyright 2018 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package state provides high-level state wrappers.
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package state
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import (
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"fmt"
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"io"
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"gvisor.googlesource.com/gvisor/pkg/log"
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"gvisor.googlesource.com/gvisor/pkg/sentry/inet"
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"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
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"gvisor.googlesource.com/gvisor/pkg/sentry/watchdog"
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"gvisor.googlesource.com/gvisor/pkg/state/statefile"
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"gvisor.googlesource.com/gvisor/pkg/syserror"
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)
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var previousMetadata map[string]string
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// ErrStateFile is returned when an error is encountered writing the statefile
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// (which may occur during open or close calls in addition to write).
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type ErrStateFile struct {
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err error
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}
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// Error implements error.Error().
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func (e ErrStateFile) Error() string {
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return fmt.Sprintf("statefile error: %v", e.err)
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}
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// SaveOpts contains save-related options.
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type SaveOpts struct {
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// Destination is the save target.
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Destination io.Writer
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// Key is used for state integrity check.
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Key []byte
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// Metadata is save metadata.
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Metadata map[string]string
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// Callback is called prior to unpause, with any save error.
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Callback func(err error)
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}
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// Save saves the system state.
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func (opts SaveOpts) Save(k *kernel.Kernel, w *watchdog.Watchdog) error {
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log.Infof("Sandbox save started, pausing all tasks.")
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k.Pause()
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defer k.Unpause()
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defer log.Infof("Tasks resumed after save.")
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w.Stop()
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defer w.Start()
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// Supplement the metadata.
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if opts.Metadata == nil {
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opts.Metadata = make(map[string]string)
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}
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addSaveMetadata(opts.Metadata)
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// Open the statefile.
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wc, err := statefile.NewWriter(opts.Destination, opts.Key, opts.Metadata)
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if err != nil {
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err = ErrStateFile{err}
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} else {
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// Save the kernel.
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err = k.SaveTo(wc)
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// ENOSPC is a state file error. This error can only come from
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// writing the state file, and not from fs.FileOperations.Fsync
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// because we wrap those in kernel.TaskSet.flushWritesToFiles.
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if err == syserror.ENOSPC {
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err = ErrStateFile{err}
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}
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if closeErr := wc.Close(); err == nil && closeErr != nil {
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err = ErrStateFile{closeErr}
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}
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}
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opts.Callback(err)
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return err
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}
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// LoadOpts contains load-related options.
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type LoadOpts struct {
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// Destination is the load source.
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Source io.Reader
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// Key is used for state integrity check.
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Key []byte
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}
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// Load loads the given kernel, setting the provided platform and stack.
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func (opts LoadOpts) Load(k *kernel.Kernel, n inet.Stack) error {
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// Open the file.
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r, m, err := statefile.NewReader(opts.Source, opts.Key)
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if err != nil {
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return ErrStateFile{err}
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}
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previousMetadata = m
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// Restore the Kernel object graph.
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return k.LoadFrom(r, n)
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}
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