// Copyright 2020 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 cmd import ( "context" "fmt" "os" "github.com/google/subcommands" "gvisor.dev/gvisor/pkg/state" "gvisor.dev/gvisor/pkg/state/statefile" "gvisor.dev/gvisor/runsc/flag" ) // Statefile implements subcommands.Command for the "statefile" command. type Statefile struct { list bool get string key string output string html bool } // Name implements subcommands.Command. func (*Statefile) Name() string { return "state" } // Synopsis implements subcommands.Command. func (*Statefile) Synopsis() string { return "shows information about a statefile" } // Usage implements subcommands.Command. func (*Statefile) Usage() string { return `statefile [flags] ` } // SetFlags implements subcommands.Command. func (s *Statefile) SetFlags(f *flag.FlagSet) { f.BoolVar(&s.list, "list", false, "lists the metdata in the statefile.") f.StringVar(&s.get, "get", "", "extracts the given metadata key.") f.StringVar(&s.key, "key", "", "the integrity key for the file.") f.StringVar(&s.output, "output", "", "target to write the result.") f.BoolVar(&s.html, "html", false, "outputs in HTML format.") } // Execute implements subcommands.Command.Execute. func (s *Statefile) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus { // Check arguments. if s.list && s.get != "" { Fatalf("error: can't specify -list and -get simultaneously.") } // Setup output. var output = os.Stdout // Default. if s.output != "" { f, err := os.OpenFile(s.output, os.O_WRONLY|os.O_TRUNC|os.O_CREATE, 0644) if err != nil { Fatalf("error opening output: %v", err) } defer func() { if err := f.Close(); err != nil { Fatalf("error flushing output: %v", err) } }() output = f } // Open the file. if f.NArg() != 1 { f.Usage() return subcommands.ExitUsageError } input, err := os.Open(f.Arg(0)) if err != nil { Fatalf("error opening input: %v\n", err) } if s.html { fmt.Fprintf(output, "\n") defer fmt.Fprintf(output, "\n") } // Dump the full file? if !s.list && s.get == "" { var key []byte if s.key != "" { key = []byte(s.key) } rc, _, err := statefile.NewReader(input, key) if err != nil { Fatalf("error parsing statefile: %v", err) } if err := state.PrettyPrint(output, rc, s.html); err != nil { Fatalf("error printing state: %v", err) } return subcommands.ExitSuccess } // Load just the metadata. metadata, err := statefile.MetadataUnsafe(input) if err != nil { Fatalf("error reading metadata: %v", err) } // Is it a single key? if s.get != "" { val, ok := metadata[s.get] if !ok { Fatalf("metadata key %s: not found", s.get) } fmt.Fprintf(output, "%s\n", val) return subcommands.ExitSuccess } // List all keys. if s.html { fmt.Fprintf(output, "

\n") defer fmt.Fprintf(output, " \n") } for key := range metadata { if s.html { fmt.Fprintf(output, "

\n", key) } else { fmt.Fprintf(output, "%s\n", key) } } return subcommands.ExitSuccess }