github.com/nicocha30/gvisor-ligolo@v0.0.0-20230726075806-989fa2c0a413/pkg/sentry/state/state.go (about)

     1  // Copyright 2018 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // Package state provides high-level state wrappers.
    16  package state
    17  
    18  import (
    19  	"fmt"
    20  	"io"
    21  
    22  	"github.com/nicocha30/gvisor-ligolo/pkg/context"
    23  	"github.com/nicocha30/gvisor-ligolo/pkg/errors/linuxerr"
    24  	"github.com/nicocha30/gvisor-ligolo/pkg/log"
    25  	"github.com/nicocha30/gvisor-ligolo/pkg/sentry/inet"
    26  	"github.com/nicocha30/gvisor-ligolo/pkg/sentry/kernel"
    27  	"github.com/nicocha30/gvisor-ligolo/pkg/sentry/time"
    28  	"github.com/nicocha30/gvisor-ligolo/pkg/sentry/vfs"
    29  	"github.com/nicocha30/gvisor-ligolo/pkg/sentry/watchdog"
    30  	"github.com/nicocha30/gvisor-ligolo/pkg/state/statefile"
    31  )
    32  
    33  var previousMetadata map[string]string
    34  
    35  // ErrStateFile is returned when an error is encountered writing the statefile
    36  // (which may occur during open or close calls in addition to write).
    37  type ErrStateFile struct {
    38  	err error
    39  }
    40  
    41  // Error implements error.Error().
    42  func (e ErrStateFile) Error() string {
    43  	return fmt.Sprintf("statefile error: %v", e.err)
    44  }
    45  
    46  // SaveOpts contains save-related options.
    47  type SaveOpts struct {
    48  	// Destination is the save target.
    49  	Destination io.Writer
    50  
    51  	// Key is used for state integrity check.
    52  	Key []byte
    53  
    54  	// Metadata is save metadata.
    55  	Metadata map[string]string
    56  
    57  	// Callback is called prior to unpause, with any save error.
    58  	Callback func(err error)
    59  }
    60  
    61  // Save saves the system state.
    62  func (opts SaveOpts) Save(ctx context.Context, k *kernel.Kernel, w *watchdog.Watchdog) error {
    63  	log.Infof("Sandbox save started, pausing all tasks.")
    64  	k.Pause()
    65  	k.ReceiveTaskStates()
    66  	defer func() {
    67  		k.Unpause()
    68  		log.Infof("Tasks resumed after save.")
    69  	}()
    70  
    71  	w.Stop()
    72  	defer w.Start()
    73  
    74  	// Supplement the metadata.
    75  	if opts.Metadata == nil {
    76  		opts.Metadata = make(map[string]string)
    77  	}
    78  	addSaveMetadata(opts.Metadata)
    79  
    80  	// Open the statefile.
    81  	wc, err := statefile.NewWriter(opts.Destination, opts.Key, opts.Metadata)
    82  	if err != nil {
    83  		err = ErrStateFile{err}
    84  	} else {
    85  		// Save the kernel.
    86  		err = k.SaveTo(ctx, wc)
    87  
    88  		// ENOSPC is a state file error. This error can only come from
    89  		// writing the state file, and not from fs.FileOperations.Fsync
    90  		// because we wrap those in kernel.TaskSet.flushWritesToFiles.
    91  		if linuxerr.Equals(linuxerr.ENOSPC, err) {
    92  			err = ErrStateFile{err}
    93  		}
    94  
    95  		if closeErr := wc.Close(); err == nil && closeErr != nil {
    96  			err = ErrStateFile{closeErr}
    97  		}
    98  	}
    99  	opts.Callback(err)
   100  	return err
   101  }
   102  
   103  // LoadOpts contains load-related options.
   104  type LoadOpts struct {
   105  	// Destination is the load source.
   106  	Source io.Reader
   107  
   108  	// Key is used for state integrity check.
   109  	Key []byte
   110  }
   111  
   112  // Load loads the given kernel, setting the provided platform and stack.
   113  func (opts LoadOpts) Load(ctx context.Context, k *kernel.Kernel, timeReady chan struct{}, n inet.Stack, clocks time.Clocks, vfsOpts *vfs.CompleteRestoreOptions) error {
   114  	// Open the file.
   115  	r, m, err := statefile.NewReader(opts.Source, opts.Key)
   116  	if err != nil {
   117  		return ErrStateFile{err}
   118  	}
   119  
   120  	previousMetadata = m
   121  
   122  	// Restore the Kernel object graph.
   123  	return k.LoadFrom(ctx, r, timeReady, n, clocks, vfsOpts)
   124  }