Refactor tool output (#127)

Signed-off-by: Daniel Weiße <dw@edgeless.systems>
Co-authored-by: Benedict Schlüter <bs@edgeless.systems>

hack/image-measurement/main.go

@@ -16,10 +16,12 @@ import (
 	"syscall"
 
 	"github.com/edgelesssys/constellation/hack/image-measurement/server"
+	"github.com/edgelesssys/constellation/internal/config"
 	"github.com/edgelesssys/constellation/internal/logger"
 	"go.uber.org/multierr"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
+	"gopkg.in/yaml.v3"
 	"libvirt.org/go/libvirt"
 )
 
@@ -280,10 +282,10 @@ func (l *libvirtInstance) deleteLibvirtInstance() error {
 	return err
 }
 
-func (l *libvirtInstance) obtainMeasurements() (err error) {
+func (l *libvirtInstance) obtainMeasurements() (measurements config.Measurements, err error) {
 	// sanity check
 	if err := l.deleteLibvirtInstance(); err != nil {
-		return err
+		return nil, err
 	}
 	done := make(chan struct{}, 1)
 	serv := server.New(l.log, done)
@@ -296,7 +298,7 @@ func (l *libvirtInstance) obtainMeasurements() (err error) {
 		err = multierr.Append(err, l.deleteLibvirtInstance())
 	}()
 	if err := l.createLibvirtInstance(); err != nil {
-		return err
+		return nil, err
 	}
 	sigs := make(chan os.Signal, 1)
 	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
@@ -310,19 +312,26 @@ func (l *libvirtInstance) obtainMeasurements() (err error) {
 	signal.Stop(sigs)
 	close(sigs)
 	if err := serv.Shutdown(); err != nil {
-		return err
+		return nil, err
 	}
 	close(done)
-	return nil
+
+	return serv.GetMeasurements(), nil
 }
 
 func main() {
-	var imageLocation string
+	var imageLocation, imageType, outFile string
-	var imageType string
+	var verboseLog bool
 	flag.StringVar(&imageLocation, "path", "", "path to the image to measure (required)")
 	flag.StringVar(&imageType, "type", "", "type of the image. One of 'qcow2' or 'raw' (required)")
+	flag.StringVar(&outFile, "file", "-", "path to output file, or '-' for stdout")
+	flag.BoolVar(&verboseLog, "v", false, "verbose logging")
+
 	flag.Parse()
-	log := logger.New(logger.JSONLog, zapcore.InfoLevel)
+	log := logger.New(logger.JSONLog, zapcore.DebugLevel)
+	if !verboseLog {
+		log = log.WithIncreasedLevel(zapcore.FatalLevel) // Only print fatal errors in non-verbose mode
+	}
 
 	if imageLocation == "" || imageType == "" {
 		flag.Usage()
@@ -343,8 +352,22 @@ func main() {
 		imagePath: imageLocation,
 	}
 
-	if err := lInstance.obtainMeasurements(); err != nil {
+	measurements, err := lInstance.obtainMeasurements()
+	if err != nil {
 		log.With(zap.Error(err)).Fatalf("Failed to obtain PCR measurements")
 	}
-	log.Infof("instaces terminated successfully")
+	log.Infof("instances terminated successfully")
+
+	output, err := yaml.Marshal(measurements)
+	if err != nil {
+		log.With(zap.Error(err)).Fatalf("Failed to marshal measurements")
+	}
+
+	if outFile == "-" {
+		fmt.Println(string(output))
+	} else {
+		if err := os.WriteFile(outFile, output, 0o644); err != nil {
+			log.With(zap.Error(err)).Fatalf("Failed to write measurements to file")
+		}
+	}
 }

hack/image-measurement/server/server.go

@@ -17,9 +17,10 @@ import (
 )
 
 type Server struct {
-	log    *logger.Logger
+	log          *logger.Logger
-	server http.Server
+	server       http.Server
-	done   chan<- struct{}
+	measurements map[uint32][]byte
+	done         chan<- struct{}
 }
 
 func New(log *logger.Logger, done chan<- struct{}) *Server {
@@ -77,5 +78,12 @@ func (s *Server) logPCRs(w http.ResponseWriter, r *http.Request) {
 	log.Infof("PCR 4 %x", pcrs[4])
 	log.Infof("PCR 8 %x", pcrs[8])
 	log.Infof("PCR 9 %x", pcrs[9])
+
+	s.measurements = pcrs
+
 	s.done <- struct{}{}
 }
+
+func (s *Server) GetMeasurements() map[uint32][]byte {
+	return s.measurements
+}