Support applying with parent directories

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

diff/apply/apply_linux.go

@@ -24,6 +24,7 @@ import (
 	"strings"
 
 	"github.com/containerd/containerd/archive"
+	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/mount"
 	"github.com/pkg/errors"
 )
@@ -31,60 +32,97 @@ import (
 func apply(ctx context.Context, mounts []mount.Mount, r io.Reader) error {
 	switch {
 	case len(mounts) == 1 && mounts[0].Type == "overlay":
-		path, err := getOverlayPath(mounts[0].Options)
+		path, parents, err := getOverlayPath(mounts[0].Options)
 		if err != nil {
+			if errdefs.IsInvalidArgument(err) {
+				break
+			}
 			return err
 		}
-		_, err = archive.Apply(ctx, path, r,
-			archive.WithConvertWhiteout(archive.OverlayConvertWhiteout))
+		opts := []archive.ApplyOpt{
+			archive.WithConvertWhiteout(archive.OverlayConvertWhiteout),
+		}
+		if len(parents) > 0 {
+			opts = append(opts, archive.WithParents(parents))
+		}
+		_, err = archive.Apply(ctx, path, r, opts...)
 		return err
 	case len(mounts) == 1 && mounts[0].Type == "aufs":
-		path, err := getAufsPath(mounts[0].Options)
+		path, parents, err := getAufsPath(mounts[0].Options)
 		if err != nil {
+			if errdefs.IsInvalidArgument(err) {
+				break
+			}
 			return err
 		}
-		_, err = archive.Apply(ctx, path, r,
-			archive.WithConvertWhiteout(archive.AufsConvertWhiteout))
+		opts := []archive.ApplyOpt{
+			archive.WithConvertWhiteout(archive.AufsConvertWhiteout),
+		}
+		if len(parents) > 0 {
+			opts = append(opts, archive.WithParents(parents))
+		}
+		_, err = archive.Apply(ctx, path, r, opts...)
 		return err
-	default:
-		return mount.WithTempMount(ctx, mounts, func(root string) error {
-			_, err := archive.Apply(ctx, root, r)
-			return err
-		})
 	}
+	return mount.WithTempMount(ctx, mounts, func(root string) error {
+		_, err := archive.Apply(ctx, root, r)
+		return err
+	})
 }
 
-func getOverlayPath(options []string) (string, error) {
+func getOverlayPath(options []string) (upper string, lower []string, err error) {
 	const upperdirPrefix = "upperdir="
+	const lowerdirPrefix = "lowerdir="
+
 	for _, o := range options {
 		if strings.HasPrefix(o, upperdirPrefix) {
-			return strings.TrimPrefix(o, upperdirPrefix), nil
+			upper = strings.TrimPrefix(o, upperdirPrefix)
+		} else if strings.HasPrefix(o, lowerdirPrefix) {
+			lower = strings.Split(strings.TrimPrefix(o, lowerdirPrefix), ":")
 		}
 	}
-	return "", errors.New("upperdir not found")
+	if upper == "" {
+		return "", nil, errors.Wrap(errdefs.ErrInvalidArgument, "upperdir not found")
+	}
+
+	return
 }
 
-func getAufsPath(options []string) (string, error) {
+// getAufsPath handles options as given by the containerd aufs package only,
+// formatted as "br:<upper>=rw[:<lower>=ro+wh]*"
+func getAufsPath(options []string) (upper string, lower []string, err error) {
 	const (
-		sep       = ":"
-		brPrefix1 = "br:"
-		brPrefix2 = "br="
-		rwSuffix  = "=rw"
+		sep      = ":"
+		brPrefix = "br:"
+		rwSuffix = "=rw"
+		roSuffix = "=ro+wh"
 	)
 	for _, o := range options {
-		if strings.HasPrefix(o, brPrefix1) {
-			o = strings.TrimPrefix(o, brPrefix1)
-		} else if strings.HasPrefix(o, brPrefix2) {
-			o = strings.TrimPrefix(o, brPrefix2)
+		if strings.HasPrefix(o, brPrefix) {
+			o = strings.TrimPrefix(o, brPrefix)
 		} else {
 			continue
 		}
+
 		for _, b := range strings.Split(o, sep) {
 			if strings.HasSuffix(b, rwSuffix) {
-				return strings.TrimSuffix(b, rwSuffix), nil
+				if upper != "" {
+					return "", nil, errors.Wrap(errdefs.ErrInvalidArgument, "multiple rw branch found")
+				}
+				upper = strings.TrimSuffix(b, rwSuffix)
+			} else if strings.HasSuffix(b, roSuffix) {
+				if upper == "" {
+					return "", nil, errors.Wrap(errdefs.ErrInvalidArgument, "rw branch be first")
+				}
+				lower = append(lower, strings.TrimSuffix(b, roSuffix))
+			} else {
+				return "", nil, errors.Wrap(errdefs.ErrInvalidArgument, "unhandled aufs suffix")
 			}
+
 		}
-		break
 	}
-	return "", errors.New("rw branch not found")
+	if upper == "" {
+		return "", nil, errors.Wrap(errdefs.ErrInvalidArgument, "rw branch not found")
+	}
+	return
 }

diff/apply/apply_linux_test.go

@@ -23,34 +23,32 @@ import (
 )
 
 func TestGetOverlayPath(t *testing.T) {
-	good := []string{"upperdir=/test/upper", "lowerdir=/test/lower", "workdir=/test/work"}
-	path, err := getOverlayPath(good)
+	good := []string{"upperdir=/test/upper", "lowerdir=/test/lower1:/test/lower2", "workdir=/test/work"}
+	path, parents, err := getOverlayPath(good)
 	if err != nil {
 		t.Fatalf("Get overlay path failed: %v", err)
 	}
 	if path != "/test/upper" {
 		t.Fatalf("Unexpected upperdir: %q", path)
 	}
+	if len(parents) != 2 || parents[0] != "/test/lower1" || parents[1] != "/test/lower2" {
+		t.Fatalf("Unexpected parents: %v", parents)
+	}
 
 	bad := []string{"lowerdir=/test/lower"}
-	_, err = getOverlayPath(bad)
+	_, _, err = getOverlayPath(bad)
 	if err == nil {
 		t.Fatalf("An error is expected")
 	}
 }
 
 func TestGetAufsPath(t *testing.T) {
-	rwDir := "/test/rw"
 	for _, test := range []struct {
 		options   []string
 		expectErr bool
 	}{
 		{
-			options:   []string{"random:option", "br:" + rwDir + "=rw:/test/ro=ro+wh"},
-			expectErr: false,
-		},
-		{
-			options:   []string{"random:option", "br=" + rwDir + "=rw:/test/ro=ro+wh"},
+			options:   []string{"random:option", "br:/test/rw=rw:/test/ro=ro+wh"},
 			expectErr: false,
 		},
 		{
@@ -62,7 +60,7 @@ func TestGetAufsPath(t *testing.T) {
 			expectErr: true,
 		},
 	} {
-		path, err := getAufsPath(test.options)
+		path, parents, err := getAufsPath(test.options)
 		if test.expectErr {
 			if err == nil {
 				t.Fatalf("An error is expected")
@@ -72,8 +70,12 @@ func TestGetAufsPath(t *testing.T) {
 		if err != nil {
 			t.Fatalf("Get aufs path failed: %v", err)
 		}
-		if path != rwDir {
+		if path != "/test/rw" {
 			t.Fatalf("Unexpected rw dir: %q", path)
 		}
+		if len(parents) != 1 || parents[0] != "/test/ro" {
+			t.Fatalf("Unexpected parents: %v", parents)
+		}
+
 	}
 }

diff/windows/windows.go

@@ -139,7 +139,7 @@ func (s windowsDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts
 		return emptyDesc, err
 	}
 
-	if _, err := archive.Apply(ctx, layer, rc, archive.WithParentLayers(parentLayerPaths), archive.AsWindowsContainerLayer()); err != nil {
+	if _, err := archive.Apply(ctx, layer, rc, archive.WithParents(parentLayerPaths), archive.AsWindowsContainerLayer()); err != nil {
 		return emptyDesc, err
 	}