cmd/oci-image-tool: fix unpacking...

Signed-off-by: Antonio Murdaca <[email protected]>

Author: runcom

image/manifest.go

@@ -25,7 +25,6 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
-	"time"
 
 	"github.com/opencontainers/image-spec/schema"
 	"github.com/pkg/errors"
@@ -107,7 +106,7 @@ func (m *manifest) unpack(w walker, dest string) error {
 			}
 
 			dd, err := filepath.Rel("blobs", filepath.Clean(path))
-			if err != nil || d.Digest != dd {
+			if err != nil || d.getDigest() != dd {
 				return nil // ignore
 			}
 
@@ -134,6 +133,7 @@ func unpackLayer(dest string, r io.Reader) error {
 	}
 	defer gz.Close()
 
+	var dirs []*tar.Header
 	tr := tar.NewReader(gz)
 
 loop:
@@ -148,7 +148,22 @@ loop:
 			return errors.Wrapf(err, "error advancing tar stream")
 		}
 
-		path := filepath.Join(dest, filepath.Clean(hdr.Name))
+		hdr.Name = filepath.Clean(hdr.Name)
+		// After calling filepath.Clean(hdr.Name) above, hdr.Name will now be in
+		// the filepath format for the OS on which the daemon is running. Hence
+		// the check for a slash-suffix MUST be done in an OS-agnostic way.
+		if !strings.HasSuffix(hdr.Name, string(os.PathSeparator)) {
+			// Not the root directory, ensure that the parent directory exists
+			parent := filepath.Dir(hdr.Name)
+			parentPath := filepath.Join(dest, parent)
+			if _, err := os.Lstat(parentPath); err != nil && os.IsNotExist(err) {
+				err = os.MkdirAll(parentPath, 0777)
+				if err != nil {
+					return err
+				}
+			}
+		}
+		path := filepath.Join(dest, hdr.Name)
 		info := hdr.FileInfo()
 
 		if strings.HasPrefix(info.Name(), ".wh.") {
@@ -163,8 +178,10 @@ loop:
 
 		switch hdr.Typeflag {
 		case tar.TypeDir:
-			if err := os.MkdirAll(path, info.Mode()); err != nil {
-				return errors.Wrap(err, "error creating directory")
+			if fi, err := os.Lstat(path); !(err == nil && fi.IsDir()) {
+				if err := os.MkdirAll(path, info.Mode()); err != nil {
+					return errors.Wrap(err, "error creating directory")
+				}
 			}
 
 		case tar.TypeReg, tar.TypeRegA:
@@ -200,13 +217,19 @@ loop:
 			if err := os.Symlink(hdr.Linkname, path); err != nil {
 				return err
 			}
-
 		}
+		// Directory mtimes must be handled at the end to avoid further
+		// file creation in them to modify the directory mtime
+		if hdr.Typeflag == tar.TypeDir {
+			dirs = append(dirs, hdr)
+		}
+	}
+	for _, hdr := range dirs {
+		path := filepath.Join(dest, hdr.Name)
 
-		if err := os.Chtimes(path, time.Now().UTC(), info.ModTime()); err != nil {
+		if err := os.Chtimes(path, hdr.AccessTime, hdr.ModTime); err != nil {
 			return errors.Wrap(err, "error changing time")
 		}
 	}
-
 	return nil
 }