dump: Extract tar code to internal/dump

internal/dump/acl.go

@@ -0,0 +1,120 @@
+package dump
+
+// Adapted from https://github.com/maxymania/go-system/blob/master/posix_acl/posix_acl.go
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+)
+
+const (
+	aclUserOwner  = 0x0001
+	aclUser       = 0x0002
+	aclGroupOwner = 0x0004
+	aclGroup      = 0x0008
+	aclMask       = 0x0010
+	aclOthers     = 0x0020
+)
+
+type aclSID uint64
+
+type aclElem struct {
+	Tag  uint16
+	Perm uint16
+	ID   uint32
+}
+
+type acl struct {
+	Version uint32
+	List    []aclElement
+}
+
+type aclElement struct {
+	aclSID
+	Perm uint16
+}
+
+func (a aclSID) getType() int {
+	return int(a >> 32)
+}
+func (a aclSID) getID() uint32 {
+	return uint32(a & 0xffffffff)
+}
+func (a aclSID) String() string {
+	switch a >> 32 {
+	case aclUserOwner:
+		return "user::"
+	case aclUser:
+		return fmt.Sprintf("user:%v:", a.getID())
+	case aclGroupOwner:
+		return "group::"
+	case aclGroup:
+		return fmt.Sprintf("group:%v:", a.getID())
+	case aclMask:
+		return "mask::"
+	case aclOthers:
+		return "other::"
+	}
+	return "?:"
+}
+
+func (a aclElement) String() string {
+	str := ""
+	if (a.Perm & 4) != 0 {
+		str += "r"
+	} else {
+		str += "-"
+	}
+	if (a.Perm & 2) != 0 {
+		str += "w"
+	} else {
+		str += "-"
+	}
+	if (a.Perm & 1) != 0 {
+		str += "x"
+	} else {
+		str += "-"
+	}
+	return fmt.Sprintf("%v%v", a.aclSID, str)
+}
+
+func (a *acl) decode(xattr []byte) {
+	var elem aclElement
+	ae := new(aclElem)
+	nr := bytes.NewReader(xattr)
+	e := binary.Read(nr, binary.LittleEndian, &a.Version)
+	if e != nil {
+		a.Version = 0
+		return
+	}
+	if len(a.List) > 0 {
+		a.List = a.List[:0]
+	}
+	for binary.Read(nr, binary.LittleEndian, ae) == nil {
+		elem.aclSID = (aclSID(ae.Tag) << 32) | aclSID(ae.ID)
+		elem.Perm = ae.Perm
+		a.List = append(a.List, elem)
+	}
+}
+
+func (a *acl) encode() []byte {
+	buf := new(bytes.Buffer)
+	ae := new(aclElem)
+	binary.Write(buf, binary.LittleEndian, &a.Version)
+	for _, elem := range a.List {
+		ae.Tag = uint16(elem.getType())
+		ae.Perm = elem.Perm
+		ae.ID = elem.getID()
+		binary.Write(buf, binary.LittleEndian, ae)
+	}
+	return buf.Bytes()
+}
+
+func (a *acl) String() string {
+	var finalacl string
+	for _, acl := range a.List {
+		finalacl += acl.String() + "\n"
+	}
+	return finalacl
+}

internal/dump/acl_test.go

@@ -0,0 +1,96 @@
+package dump
+
+import (
+	"reflect"
+	"testing"
+)
+
+func Test_acl_decode(t *testing.T) {
+	type args struct {
+		xattr []byte
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			name: "decode string",
+			args: args{
+				xattr: []byte{2, 0, 0, 0, 1, 0, 6, 0, 255, 255, 255, 255, 2, 0, 7, 0, 0, 0, 0, 0, 2, 0, 7, 0, 254, 255, 0, 0, 4, 0, 7, 0, 255, 255, 255, 255, 16, 0, 7, 0, 255, 255, 255, 255, 32, 0, 4, 0, 255, 255, 255, 255},
+			},
+			want: "user::rw-\nuser:0:rwx\nuser:65534:rwx\ngroup::rwx\nmask::rwx\nother::r--\n",
+		},
+		{
+			name: "decode fail",
+			args: args{
+				xattr: []byte("abctest"),
+			},
+			want: "",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			a := &acl{}
+			a.decode(tt.args.xattr)
+			if tt.want != a.String() {
+				t.Errorf("acl.decode() = %v, want: %v", a.String(), tt.want)
+			}
+		})
+	}
+}
+
+func Test_acl_encode(t *testing.T) {
+	tests := []struct {
+		name string
+		want []byte
+		args []aclElement
+	}{
+		{
+			name: "encode values",
+			want: []byte{2, 0, 0, 0, 1, 0, 6, 0, 255, 255, 255, 255, 2, 0, 7, 0, 0, 0, 0, 0, 2, 0, 7, 0, 254, 255, 0, 0, 4, 0, 7, 0, 255, 255, 255, 255, 16, 0, 7, 0, 255, 255, 255, 255, 32, 0, 4, 0, 255, 255, 255, 255},
+			args: []aclElement{
+				{
+					aclSID: 8589934591,
+					Perm:   6,
+				},
+				{
+					aclSID: 8589934592,
+					Perm:   7,
+				},
+				{
+					aclSID: 8590000126,
+					Perm:   7,
+				},
+				{
+					aclSID: 21474836479,
+					Perm:   7,
+				},
+				{
+					aclSID: 73014444031,
+					Perm:   7,
+				},
+				{
+					aclSID: 141733920767,
+					Perm:   4,
+				},
+			},
+		},
+		{
+			name: "encode fail",
+			want: []byte{2, 0, 0, 0},
+			args: []aclElement{},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			a := &acl{
+				Version: 2,
+				List:    tt.args,
+			}
+			if got := a.encode(); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("acl.encode() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

internal/dump/tar.go

@@ -0,0 +1,158 @@
+package dump
+
+import (
+	"archive/tar"
+	"context"
+	"io"
+	"path"
+	"strings"
+
+	"github.com/restic/restic/internal/errors"
+	"github.com/restic/restic/internal/restic"
+	"github.com/restic/restic/internal/walker"
+)
+
+// WriteTar will write the contents of the given tree, encoded as a tar to the given destination.
+// It will loop over all nodes in the tree and dump them recursively.
+func WriteTar(ctx context.Context, repo restic.Repository, tree *restic.Tree, rootPath string, dst io.Writer) error {
+	tw := tar.NewWriter(dst)
+
+	for _, rootNode := range tree.Nodes {
+		rootNode.Path = rootPath
+		err := tarTree(ctx, repo, rootNode, rootPath, tw)
+		if err != nil {
+			_ = tw.Close()
+			return err
+		}
+	}
+	return tw.Close()
+}
+
+func tarTree(ctx context.Context, repo restic.Repository, rootNode *restic.Node, rootPath string, tw *tar.Writer) error {
+	rootNode.Path = path.Join(rootNode.Path, rootNode.Name)
+	rootPath = rootNode.Path
+
+	if err := tarNode(ctx, tw, rootNode, repo); err != nil {
+		return err
+	}
+
+	// If this is no directory we are finished
+	if !IsDir(rootNode) {
+		return nil
+	}
+
+	err := walker.Walk(ctx, repo, *rootNode.Subtree, nil, func(_ restic.ID, nodepath string, node *restic.Node, err error) (bool, error) {
+		if err != nil {
+			return false, err
+		}
+		if node == nil {
+			return false, nil
+		}
+
+		node.Path = path.Join(rootPath, nodepath)
+
+		if IsFile(node) || IsLink(node) || IsDir(node) {
+			err := tarNode(ctx, tw, node, repo)
+			if err != nil {
+				return false, err
+			}
+		}
+
+		return false, nil
+	})
+
+	return err
+}
+
+func tarNode(ctx context.Context, tw *tar.Writer, node *restic.Node, repo restic.Repository) error {
+	header := &tar.Header{
+		Name:       node.Path,
+		Size:       int64(node.Size),
+		Mode:       int64(node.Mode),
+		Uid:        int(node.UID),
+		Gid:        int(node.GID),
+		ModTime:    node.ModTime,
+		AccessTime: node.AccessTime,
+		ChangeTime: node.ChangeTime,
+		PAXRecords: parseXattrs(node.ExtendedAttributes),
+	}
+
+	if IsLink(node) {
+		header.Typeflag = tar.TypeSymlink
+		header.Linkname = node.LinkTarget
+	}
+
+	if IsDir(node) {
+		header.Typeflag = tar.TypeDir
+	}
+
+	err := tw.WriteHeader(header)
+
+	if err != nil {
+		return errors.Wrap(err, "TarHeader ")
+	}
+
+	return GetNodeData(ctx, tw, repo, node)
+}
+
+func parseXattrs(xattrs []restic.ExtendedAttribute) map[string]string {
+	tmpMap := make(map[string]string)
+
+	for _, attr := range xattrs {
+		attrString := string(attr.Value)
+
+		if strings.HasPrefix(attr.Name, "system.posix_acl_") {
+			na := acl{}
+			na.decode(attr.Value)
+
+			if na.String() != "" {
+				if strings.Contains(attr.Name, "system.posix_acl_access") {
+					tmpMap["SCHILY.acl.access"] = na.String()
+				} else if strings.Contains(attr.Name, "system.posix_acl_default") {
+					tmpMap["SCHILY.acl.default"] = na.String()
+				}
+			}
+
+		} else {
+			tmpMap["SCHILY.xattr."+attr.Name] = attrString
+		}
+	}
+
+	return tmpMap
+}
+
+// GetNodeData will write the contents of the node to the given output
+func GetNodeData(ctx context.Context, output io.Writer, repo restic.Repository, node *restic.Node) error {
+	var (
+		buf []byte
+		err error
+	)
+	for _, id := range node.Content {
+		buf, err = repo.LoadBlob(ctx, restic.DataBlob, id, buf)
+		if err != nil {
+			return err
+		}
+
+		_, err = output.Write(buf)
+		if err != nil {
+			return errors.Wrap(err, "Write")
+		}
+
+	}
+	return nil
+}
+
+// IsDir checks if the given node is a directory
+func IsDir(node *restic.Node) bool {
+	return node.Type == "dir"
+}
+
+// IsLink checks if the given node as a link
+func IsLink(node *restic.Node) bool {
+	return node.Type == "symlink"
+}
+
+// IsFile checks if the given node is a file
+func IsFile(node *restic.Node) bool {
+	return node.Type == "file"
+}