Add statefile command to runsc.

PiperOrigin-RevId: 296105337
author: Adin Scannell <ascannell@google.com> 2020-02-19 18:27:48 -0800
committer: Copybara-Service <copybara-worker@google.com> 2020-02-19 18:28:42 -0800
commit: ec5630527bc4473081048d2d13d1dcfadc6c7cdd (patch)
tree: ac8922a25edcd7271f6978f82b85c8a1c698791b
parent: 30794512d3977ebb2b185e5e9cfb969d558a07a4 (diff)
3 files changed, 148 insertions, 1 deletions
diff --git a/runsc/cmd/BUILD b/runsc/cmd/BUILD
index 2a88b85a9..d0bb4613a 100644
--- a/runsc/cmd/BUILD
+++ b/runsc/cmd/BUILD
@@ -31,6 +31,7 @@ go_library(
         "spec.go",
         "start.go",
         "state.go",
+        "statefile.go",
         "syscalls.go",
         "wait.go",
     ],
@@ -43,6 +44,8 @@ go_library(
         "//pkg/sentry/control",
         "//pkg/sentry/kernel",
         "//pkg/sentry/kernel/auth",
+        "//pkg/state",
+        "//pkg/state/statefile",
         "//pkg/sync",
         "//pkg/unet",
         "//pkg/urpc",
diff --git a/runsc/cmd/statefile.go b/runsc/cmd/statefile.go
new file mode 100644
index 000000000..e6f1907da
--- /dev/null
+++ b/runsc/cmd/statefile.go
@@ -0,0 +1,143 @@
+// 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] <statefile>`
+}
+
+// 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, "<html><body>\n")
+		defer fmt.Fprintf(output, "</body></html>\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, " <ul>\n")
+		defer fmt.Fprintf(output, " </ul>\n")
+	}
+	for key := range metadata {
+		if s.html {
+			fmt.Fprintf(output, "  <li>%s</li>\n", key)
+		} else {
+			fmt.Fprintf(output, "%s\n", key)
+		}
+	}
+	return subcommands.ExitSuccess
+}
diff --git a/runsc/main.go b/runsc/main.go
index 762b0f801..af73bed97 100644
--- a/runsc/main.go
+++ b/runsc/main.go
@@ -116,8 +116,8 @@ func main() {
 	subcommands.Register(new(cmd.Resume), "")
 	subcommands.Register(new(cmd.Run), "")
 	subcommands.Register(new(cmd.Spec), "")
-	subcommands.Register(new(cmd.Start), "")
 	subcommands.Register(new(cmd.State), "")
+	subcommands.Register(new(cmd.Start), "")
 	subcommands.Register(new(cmd.Wait), "")
 
 	// Register internal commands with the internal group name. This causes
@@ -127,6 +127,7 @@ func main() {
 	subcommands.Register(new(cmd.Boot), internalGroup)
 	subcommands.Register(new(cmd.Debug), internalGroup)
 	subcommands.Register(new(cmd.Gofer), internalGroup)
+	subcommands.Register(new(cmd.Statefile), internalGroup)
 
 	// All subcommands must be registered before flag parsing.
 	flag.Parse()
author	Adin Scannell <ascannell@google.com>	2020-02-19 18:27:48 -0800
committer	Copybara-Service <copybara-worker@google.com>	2020-02-19 18:28:42 -0800
commit	ec5630527bc4473081048d2d13d1dcfadc6c7cdd (patch)
tree	ac8922a25edcd7271f6978f82b85c8a1c698791b
parent	30794512d3977ebb2b185e5e9cfb969d558a07a4 (diff)