github.com/MerlinKodo/gvisor@v0.0.0-20231110090155-957f62ecf90e/runsc/cmd/trace/create.go (about)

     1  // Copyright 2020 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 trace
    16  
    17  import (
    18  	"context"
    19  	"encoding/json"
    20  	"fmt"
    21  	"os"
    22  
    23  	"github.com/MerlinKodo/gvisor/pkg/log"
    24  	"github.com/MerlinKodo/gvisor/pkg/sentry/seccheck"
    25  	"github.com/MerlinKodo/gvisor/runsc/boot"
    26  	"github.com/MerlinKodo/gvisor/runsc/cmd/util"
    27  	"github.com/MerlinKodo/gvisor/runsc/config"
    28  	"github.com/MerlinKodo/gvisor/runsc/container"
    29  	"github.com/MerlinKodo/gvisor/runsc/flag"
    30  	"github.com/google/subcommands"
    31  )
    32  
    33  // create implements subcommands.Command for the "create" command.
    34  type create struct {
    35  	config string
    36  	force  bool
    37  }
    38  
    39  // Name implements subcommands.Command.
    40  func (*create) Name() string {
    41  	return "create"
    42  }
    43  
    44  // Synopsis implements subcommands.Command.
    45  func (*create) Synopsis() string {
    46  	return "create a trace session"
    47  }
    48  
    49  // Usage implements subcommands.Command.
    50  func (*create) Usage() string {
    51  	return `create [flags] <sandbox id> - create a trace session
    52  `
    53  }
    54  
    55  // SetFlags implements subcommands.Command.
    56  func (l *create) SetFlags(f *flag.FlagSet) {
    57  	f.StringVar(&l.config, "config", "", "path to the JSON file that describes the session being created")
    58  	f.BoolVar(&l.force, "force", false, "deletes a conflicting session, if one exists")
    59  }
    60  
    61  // Execute implements subcommands.Command.
    62  func (l *create) Execute(_ context.Context, f *flag.FlagSet, args ...any) subcommands.ExitStatus {
    63  	if f.NArg() != 1 {
    64  		f.Usage()
    65  		return subcommands.ExitUsageError
    66  	}
    67  	if len(l.config) == 0 {
    68  		f.Usage()
    69  		return util.Errorf("missing path to configuration file, please set --config=[path]")
    70  	}
    71  
    72  	sessionConfig, err := decodeTraceConfig(l.config)
    73  	if err != nil {
    74  		return util.Errorf("loading config file: %v", err)
    75  	}
    76  
    77  	id := f.Arg(0)
    78  	conf := args[0].(*config.Config)
    79  
    80  	opts := container.LoadOpts{
    81  		SkipCheck:     true,
    82  		RootContainer: true,
    83  	}
    84  	c, err := container.Load(conf.RootDir, container.FullID{ContainerID: id}, opts)
    85  	if err != nil {
    86  		util.Fatalf("loading sandbox: %v", err)
    87  	}
    88  
    89  	if err := c.Sandbox.CreateTraceSession(sessionConfig, l.force); err != nil {
    90  		util.Fatalf("creating session: %v", err)
    91  	}
    92  
    93  	fmt.Printf("Trace session %q created.\n", sessionConfig.Name)
    94  	return subcommands.ExitSuccess
    95  }
    96  
    97  func decodeTraceConfig(path string) (*seccheck.SessionConfig, error) {
    98  	file, err := os.Open(path)
    99  	if err != nil {
   100  		return nil, err
   101  	}
   102  	defer file.Close()
   103  
   104  	decoder := json.NewDecoder(file)
   105  	decoder.DisallowUnknownFields()
   106  	sessionConfig := &seccheck.SessionConfig{}
   107  	err = decoder.Decode(sessionConfig)
   108  	if err == nil {
   109  		// Success, we're done.
   110  		return sessionConfig, nil
   111  	}
   112  
   113  	// If file cannot be decoded as a SessionConfig, try with InitConfig as
   114  	// convenience in case the caller wants to reuse a trace session from
   115  	// InitConfig file.
   116  	log.Debugf("Config file is not a seccheck.SessionConfig, try with boot.InitConfig instead: %v", err)
   117  	if _, err := file.Seek(0, 0); err != nil {
   118  		return nil, err
   119  	}
   120  	initConfig := &boot.InitConfig{}
   121  	if err := decoder.Decode(initConfig); err != nil {
   122  		return nil, fmt.Errorf("invalid configuration file: %w", err)
   123  	}
   124  	return &initConfig.TraceSession, nil
   125  }