update

analyzer/analyzer.go

@@ -1,8 +1,7 @@
 package analyzer
 
 import (
-	"os"
-	"path/filepath"
+	"io"
 
 	"github.com/knqyf263/fanal/extractor"
 	"github.com/pkg/errors"
@@ -59,11 +58,9 @@ func RequiredFilenames() []string {
 	return filenames
 }
 
-func Analyze(dir string) (filesMap extractor.FilesMap, err error) {
+func Analyze(r io.ReadCloser) (filesMap extractor.FilesMap, err error) {
 	extractor := extractor.DockerExtractor{}
-	file, _ := os.Open(filepath.Join(dir, "layer.tar"))
-
-	filesMap, err = extractor.ExtractFiles(file, RequiredFilenames())
+	filesMap, err = extractor.Extract(r, RequiredFilenames())
 	if err != nil {
 		return nil, errors.Wrap(err, "Failed to extract files")
 	}

cmd/fanal/main.go

@@ -1,21 +1,38 @@
 package main
 
 import (
+	"flag"
 	"log"
 	"os"
 
+	"golang.org/x/crypto/ssh/terminal"
+
 	"github.com/knqyf263/fanal/analyzer"
 	_ "github.com/knqyf263/fanal/analyzer/os/alpine"
 	_ "github.com/knqyf263/fanal/analyzer/pkg/apk"
 )
 
 func main() {
-	dir, err := os.Getwd()
+	tarPath := flag.String("f", "-", "layer.tar path")
+	flag.Parse()
+	rc, err := openStream(*tarPath)
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	files, _ := analyzer.Analyze(dir)
+	files, _ := analyzer.Analyze(rc)
 	analyzer.GetOS(files)
 	analyzer.GetPackages(files)
 }
+
+func openStream(path string) (*os.File, error) {
+	if path == "-" {
+		if terminal.IsTerminal(0) {
+			flag.Usage()
+			os.Exit(64)
+		} else {
+			return os.Stdin, nil
+		}
+	}
+	return os.Open(path)
+}

extractor/docker.go

@@ -2,14 +2,66 @@ package extractor
 
 import (
 	"archive/tar"
+	"encoding/json"
 	"io"
 	"io/ioutil"
 	"path"
+	"path/filepath"
+	"strings"
 )
 
+type manifest struct {
+	Config   string   `json:"Config"`
+	RepoTags []string `json:"RepoTags"`
+	Layers   []string `json:"Layers"`
+}
+
 type DockerExtractor struct{}
 
-func (d DockerExtractor) ExtractFiles(layer io.ReadCloser, filenames []string) (FilesMap, error) {
+func (d DockerExtractor) Extract(r io.ReadCloser, filenames []string) (FilesMap, error) {
+	manifests := make([]manifest, 0)
+	filesInLayers := make(map[string]FilesMap)
+	tr := tar.NewReader(r)
+	for {
+		header, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, ErrCouldNotExtract
+		}
+		switch {
+		case header.Name == "manifest.json":
+			if err := json.NewDecoder(tr).Decode(&manifests); err != nil {
+				return nil, err
+			}
+		case strings.HasSuffix(header.Name, ".tar"):
+			layerID := filepath.Base(filepath.Dir(header.Name))
+			files, err := d.ExtractFiles(tr, filenames)
+			if err != nil {
+				return nil, err
+			}
+			filesInLayers[layerID] = files
+		//case strings.HasSuffix(header.Name, ".json"):
+		//	if err := json.NewDecoder(tr).Decode(&imageMeta); err != nil {
+		//		return nil, err
+		//	}
+		//	imageMetas[header.Name] = imageMeta
+		default:
+		}
+	}
+	filesMap := map[string][]byte{}
+	for _, layerID := range manifests[0].Layers {
+		layerID := strings.Split(layerID, "/")[0]
+		for k, v := range filesInLayers[layerID] {
+			filesMap[k] = v
+		}
+	}
+
+	return filesMap, nil
+
+}
+func (d DockerExtractor) ExtractFiles(layer io.Reader, filenames []string) (FilesMap, error) {
 	data := make(map[string][]byte)
 
 	tr := tar.NewReader(layer)