Add CLI support for restore endpoint.

+ Add the relevant parts to the command line tool and the client
  package.
+ Small improvements to cryptor's restore function:
  + Don't try to restore if the store is already active.
  + Flush the persistence key cache once the restoration occurs.
+ The redoctober program now explicitly mentions that a config file is
  invalid when that's the case.

client/client.go

@@ -387,3 +387,20 @@ func (c *RemoteServer) Status(req core.StatusRequest) (*core.ResponseData, error
 
 	return unmarshalResponseData(respBytes)
 }
+
+// Restore issues a restore request to the server. Note that a restore
+// request is the same as a delegation request, except that the user
+// and label lists are ignored.
+func (c *RemoteServer) Restore(req core.DelegateRequest) (*core.ResponseData, error) {
+	reqBytes, err := json.Marshal(req)
+	if err != nil {
+		return nil, err
+	}
+
+	respBytes, err := c.doAction("restore", reqBytes)
+	if err != nil {
+		return nil, err
+	}
+
+	return unmarshalResponseData(respBytes)
+}

cmd/ro/main.go

@@ -45,6 +45,7 @@ var commandSet = map[string]command{
 	"order":       command{Run: runOrder, Desc: "place an order for delegations"},
 	"owners":      command{Run: runOwner, Desc: "show owners list"},
 	"status":      command{Run: runStatus, Desc: "show Red October persistent delegation state"},
+	"restore":     command{Run: runRestore, Desc: "perform a restore delegation"},
 }
 
 func registerFlags() {
@@ -132,6 +133,29 @@ func runDelegate() {
 	fmt.Println(resp.Status)
 }
 
+func runRestore() {
+	req := core.DelegateRequest{
+		Name:     user,
+		Password: pswd,
+		Uses:     uses,
+		Time:     duration,
+	}
+
+	resp, err := roServer.Restore(req)
+	processError(err)
+
+	if resp.Status != "ok" {
+		fmt.Fprintf(os.Stderr, "failed: %s\n", resp.Status)
+		os.Exit(1)
+	}
+
+	var st core.StatusData
+	err = json.Unmarshal(resp.Response, &st)
+	processError(err)
+
+	fmt.Println("Restore delegation complete; persistence is now", st.Status)
+}
+
 // TODO: summary response needs better formatting
 func runSummary() {
 	req := core.SummaryRequest{

cryptor/cryptor.go

@@ -742,6 +742,11 @@ var ErrRestoreDelegations = errors.New("cryptor: need more delegations")
 // enough delegations are present to restore the cache, the current
 // Red October key cache is replaced with the persisted one.
 func (c *Cryptor) Restore(name, password string, uses int, slot, durationString string) error {
+	// If the persistence store is already active, don't proceed.
+	if st := c.persist.Status(); st != nil && st.State == persist.Active {
+		return nil
+	}
+
 	record, ok := c.records.GetRecord(name)
 	if !ok {
 		return errors.New("Missing user on disk")
@@ -774,6 +779,7 @@ func (c *Cryptor) Restore(name, password string, uses int, slot, durationString
 
 	c.cache = keycache.NewFrom(uk)
 	c.persist.Persist()
+	c.persist.Cache().Flush()
 	return nil
 }
 

redoctober.go

@@ -304,6 +304,9 @@ func main() {
 	}
 
 	if vaultPath == "" || !cfg.Valid() {
+		if !cfg.Valid() {
+			fmt.Fprintf(os.Stderr, "Invalid config.\n")
+		}
 		fmt.Fprint(os.Stderr, usage)
 		flag.PrintDefaults()
 		os.Exit(2)