restore: exclude/include xattrs

For: https://github.com/restic/restic/issues/5089

Signed-off-by: Tesshu Flower <tflower@redhat.com>

cmd/restic/cmd_restore.go

@@ -59,6 +59,8 @@ type RestoreOptions struct {
 	Verify              bool
 	Overwrite           restorer.OverwriteBehavior
 	Delete              bool
+	ExcludeXattrPattern []string
+	IncludeXattrPattern []string
 }
 
 var restoreOptions RestoreOptions
@@ -72,6 +74,9 @@ func init() {
 	restoreOptions.ExcludePatternOptions.Add(flags)
 	restoreOptions.IncludePatternOptions.Add(flags)
 
+	flags.StringArrayVar(&restoreOptions.ExcludeXattrPattern, "exclude-xattr", nil, "exclude xattr by `pattern` (can be specified multiple times)")
+	flags.StringArrayVar(&restoreOptions.IncludeXattrPattern, "include-xattr", nil, "include xattr by `pattern` (can be specified multiple times)")
+
 	initSingleSnapshotFilter(flags, &restoreOptions.SnapshotFilter)
 	flags.BoolVar(&restoreOptions.DryRun, "dry-run", false, "do not write any data, just show what would be done")
 	flags.BoolVar(&restoreOptions.Sparse, "sparse", false, "restore files as sparse")
@@ -96,6 +101,9 @@ func runRestore(ctx context.Context, opts RestoreOptions, gopts GlobalOptions,
 	hasExcludes := len(excludePatternFns) > 0
 	hasIncludes := len(includePatternFns) > 0
 
+	hasXattrExcludes := len(opts.ExcludeXattrPattern) > 0
+	hasXattrIncludes := len(opts.IncludeXattrPattern) > 0
+
 	switch {
 	case len(args) == 0:
 		return errors.Fatal("no snapshot ID specified")
@@ -110,6 +118,11 @@ func runRestore(ctx context.Context, opts RestoreOptions, gopts GlobalOptions,
 	if hasExcludes && hasIncludes {
 		return errors.Fatal("exclude and include patterns are mutually exclusive")
 	}
+
+	if hasXattrExcludes && hasXattrIncludes {
+		return errors.Fatal("exclude and include xattr patterns are mutually exclusive")
+	}
+
 	if opts.DryRun && opts.Verify {
 		return errors.Fatal("--dry-run and --verify are mutually exclusive")
 	}
@@ -219,6 +232,31 @@ func runRestore(ctx context.Context, opts RestoreOptions, gopts GlobalOptions,
 		res.SelectFilter = selectIncludeFilter
 	}
 
+	if !hasXattrExcludes && !hasXattrIncludes {
+		// set default of including xattrs from the 'user' namespace
+		opts.IncludeXattrPattern = []string{"user.*"}
+	}
+	if hasXattrExcludes {
+		if err := filter.ValidatePatterns(opts.ExcludeXattrPattern); err != nil {
+			return errors.Fatalf("--exclude-xattr: %s", err)
+		}
+
+		res.XattrSelectFilter = func(xattrName string) bool {
+			shouldReject := filter.RejectByPattern(opts.ExcludeXattrPattern, Warnf)(xattrName)
+			return !shouldReject
+		}
+	} else {
+		// User has either input include xattr pattern(s) or we're using our default include pattern
+		if err := filter.ValidatePatterns(opts.IncludeXattrPattern); err != nil {
+			return errors.Fatalf("--include-xattr: %s", err)
+		}
+
+		res.XattrSelectFilter = func(xattrName string) bool {
+			shouldInclude, _ := filter.IncludeByPattern(opts.IncludeXattrPattern, Warnf)(xattrName)
+			return shouldInclude
+		}
+	}
+
 	if !gopts.JSON {
 		msg.P("restoring %s to %s\n", res.Snapshot(), opts.Target)
 	}

internal/fs/node.go

@@ -230,8 +230,8 @@ func mkfifo(path string, mode uint32) (err error) {
 }
 
 // NodeRestoreMetadata restores node metadata
-func NodeRestoreMetadata(node *restic.Node, path string, warn func(msg string)) error {
+func NodeRestoreMetadata(node *restic.Node, path string, warn func(msg string), xattrSelectFilter func(xattrName string) bool) error {
-	err := nodeRestoreMetadata(node, path, warn)
+	err := nodeRestoreMetadata(node, path, warn, xattrSelectFilter)
 	if err != nil {
 		// It is common to have permission errors for folders like /home
 		// unless you're running as root, so ignore those.
@@ -246,14 +246,14 @@ func NodeRestoreMetadata(node *restic.Node, path string, warn func(msg string))
 	return err
 }
 
-func nodeRestoreMetadata(node *restic.Node, path string, warn func(msg string)) error {
+func nodeRestoreMetadata(node *restic.Node, path string, warn func(msg string), xattrSelectFilter func(xattrName string) bool) error {
 	var firsterr error
 
 	if err := lchown(path, int(node.UID), int(node.GID)); err != nil {
 		firsterr = errors.WithStack(err)
 	}
 
-	if err := nodeRestoreExtendedAttributes(node, path); err != nil {
+	if err := nodeRestoreExtendedAttributes(node, path, xattrSelectFilter); err != nil {
 		debug.Log("error restoring extended attributes for %v: %v", path, err)
 		if firsterr == nil {
 			firsterr = err

internal/fs/node_test.go

@@ -217,7 +217,8 @@ func TestNodeRestoreAt(t *testing.T) {
 				nodePath = filepath.Join(tempdir, test.Name)
 			}
 			rtest.OK(t, NodeCreateAt(&test, nodePath))
-			rtest.OK(t, NodeRestoreMetadata(&test, nodePath, func(msg string) { rtest.OK(t, fmt.Errorf("Warning triggered for path: %s: %s", nodePath, msg)) }))
+			rtest.OK(t, NodeRestoreMetadata(&test, nodePath, func(msg string) { rtest.OK(t, fmt.Errorf("Warning triggered for path: %s: %s", nodePath, msg)) },
+				func(_ string) bool { return true } /* restore all xattrs */))
 
 			fs := &Local{}
 			meta, err := fs.OpenFile(nodePath, O_NOFOLLOW, true)
@@ -292,6 +293,7 @@ func TestNodeRestoreMetadataError(t *testing.T) {
 	nodePath := filepath.Join(tempdir, node.Name)
 
 	// This will fail because the target file does not exist
-	err := NodeRestoreMetadata(node, nodePath, func(msg string) { rtest.OK(t, fmt.Errorf("Warning triggered for path: %s: %s", nodePath, msg)) })
+	err := NodeRestoreMetadata(node, nodePath, func(msg string) { rtest.OK(t, fmt.Errorf("Warning triggered for path: %s: %s", nodePath, msg)) },
+		func(_ string) bool { return true })
 	test.Assert(t, errors.Is(err, os.ErrNotExist), "failed for an unexpected reason")
 }

internal/fs/node_xattr.go

@@ -65,15 +65,18 @@ func handleXattrErr(err error) error {
 	}
 }
 
-func nodeRestoreExtendedAttributes(node *restic.Node, path string) error {
+func nodeRestoreExtendedAttributes(node *restic.Node, path string, xattrSelectFilter func(xattrName string) bool) error {
 	expectedAttrs := map[string]struct{}{}
 	for _, attr := range node.ExtendedAttributes {
+		// Only restore xattrs that match the filter
+		if xattrSelectFilter(attr.Name) {
 			err := setxattr(path, attr.Name, attr.Value)
 			if err != nil {
 				return err
 			}
 			expectedAttrs[attr.Name] = struct{}{}
 		}
+	}
 
 	// remove unexpected xattrs
 	xattrs, err := listxattr(path)
@@ -84,10 +87,13 @@ func nodeRestoreExtendedAttributes(node *restic.Node, path string) error {
 		if _, ok := expectedAttrs[name]; ok {
 			continue
 		}
+		// Only attempt to remove xattrs that match the filter
+		if xattrSelectFilter(name) {
 			if err := removexattr(path, name); err != nil {
 				return err
 			}
 		}
+	}
 
 	return nil
 }

internal/fs/node_xattr_all_test.go

@@ -26,7 +26,7 @@ func setAndVerifyXattr(t *testing.T, file string, attrs []restic.ExtendedAttribu
 		Type:               restic.NodeTypeFile,
 		ExtendedAttributes: attrs,
 	}
-	rtest.OK(t, nodeRestoreExtendedAttributes(node, file))
+	rtest.OK(t, nodeRestoreExtendedAttributes(node, file, func(_ string) bool { return true } /*restore all xattrs*/))
 
 	nodeActual := &restic.Node{
 		Type: restic.NodeTypeFile,

internal/restorer/restorer.go

@@ -31,6 +31,8 @@ type Restorer struct {
 	// SelectFilter determines whether the item is selectedForRestore or whether a childMayBeSelected.
 	// selectedForRestore must not depend on isDir as `removeUnexpectedFiles` always passes false to isDir.
 	SelectFilter func(item string, isDir bool) (selectedForRestore bool, childMayBeSelected bool)
+
+	XattrSelectFilter func(xattrName string) (xattrSelectedForRestore bool)
 }
 
 var restorerAbortOnAllErrors = func(_ string, err error) error { return err }
@@ -288,7 +290,7 @@ func (res *Restorer) restoreNodeMetadataTo(node *restic.Node, target, location s
 		return nil
 	}
 	debug.Log("restoreNodeMetadata %v %v %v", node.Name, target, location)
-	err := fs.NodeRestoreMetadata(node, target, res.Warn)
+	err := fs.NodeRestoreMetadata(node, target, res.Warn, res.XattrSelectFilter)
 	if err != nil {
 		debug.Log("node.RestoreMetadata(%s) error %v", target, err)
 	}