gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/pkg/sentry/control/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 control
    16  
    17  import (
    18  	"errors"
    19  	"fmt"
    20  
    21  	"gvisor.dev/gvisor/pkg/abi/linux"
    22  	"gvisor.dev/gvisor/pkg/log"
    23  	"gvisor.dev/gvisor/pkg/sentry/kernel"
    24  	"gvisor.dev/gvisor/pkg/sentry/pgalloc"
    25  	"gvisor.dev/gvisor/pkg/sentry/state"
    26  	"gvisor.dev/gvisor/pkg/sentry/watchdog"
    27  	"gvisor.dev/gvisor/pkg/urpc"
    28  )
    29  
    30  // ErrInvalidFiles is returned when the urpc call to Save does not include an
    31  // appropriate file payload (e.g. there is no output file!).
    32  var ErrInvalidFiles = errors.New("exactly one file must be provided")
    33  
    34  // State includes state-related functions.
    35  type State struct {
    36  	Kernel   *kernel.Kernel
    37  	Watchdog *watchdog.Watchdog
    38  }
    39  
    40  // SaveOpts contains options for the Save RPC call.
    41  type SaveOpts struct {
    42  	// Key is used for state integrity check.
    43  	Key []byte `json:"key"`
    44  
    45  	// Metadata is the set of metadata to prepend to the state file.
    46  	Metadata map[string]string `json:"metadata"`
    47  
    48  	// MemoryFileSaveOpts is passed to calls to pgalloc.MemoryFile.SaveTo().
    49  	MemoryFileSaveOpts pgalloc.SaveOpts
    50  
    51  	// HavePagesFile indicates whether the pages file and its corresponding
    52  	// metadata file is provided.
    53  	HavePagesFile bool `json:"have_pages_file"`
    54  
    55  	// FilePayload contains the following:
    56  	// 1. checkpoint state file.
    57  	// 2. optional checkpoint pages metadata file.
    58  	// 3. optional checkpoint pages file.
    59  	urpc.FilePayload
    60  
    61  	// Resume indicates if the sandbox process should continue running
    62  	// after checkpointing.
    63  	Resume bool
    64  }
    65  
    66  // Save saves the running system.
    67  func (s *State) Save(o *SaveOpts, _ *struct{}) error {
    68  	wantFiles := 1
    69  	if o.HavePagesFile {
    70  		wantFiles += 2
    71  	}
    72  	if gotFiles := len(o.FilePayload.Files); gotFiles != wantFiles {
    73  		return fmt.Errorf("got %d files, wanted %d", gotFiles, wantFiles)
    74  	}
    75  
    76  	// Save to the first provided stream.
    77  	stateFile, err := o.ReleaseFD(0)
    78  	if err != nil {
    79  		return err
    80  	}
    81  	defer stateFile.Close()
    82  	saveOpts := state.SaveOpts{
    83  		Destination:        stateFile,
    84  		Key:                o.Key,
    85  		Metadata:           o.Metadata,
    86  		MemoryFileSaveOpts: o.MemoryFileSaveOpts,
    87  		Callback: func(err error) {
    88  			if err == nil {
    89  				log.Infof("Save succeeded: exiting...")
    90  				s.Kernel.SetSaveSuccess(false /* autosave */)
    91  			} else {
    92  				log.Warningf("Save failed: %v", err)
    93  				s.Kernel.SetSaveError(err)
    94  			}
    95  			if !o.Resume {
    96  				s.Kernel.Kill(linux.WaitStatusExit(0))
    97  			}
    98  		},
    99  	}
   100  	if o.HavePagesFile {
   101  		saveOpts.PagesMetadata, err = o.ReleaseFD(1)
   102  		if err != nil {
   103  			return err
   104  		}
   105  		defer saveOpts.PagesMetadata.Close()
   106  
   107  		saveOpts.PagesFile, err = o.ReleaseFD(2)
   108  		if err != nil {
   109  			return err
   110  		}
   111  		defer saveOpts.PagesFile.Close()
   112  	}
   113  	return saveOpts.Save(s.Kernel.SupervisorContext(), s.Kernel, s.Watchdog)
   114  }