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Merge pull request #4379 from chenxiaolong/symlink_xattrs

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Add support for extended attributes on symlinks
This commit is contained in:
Michael Eischer 2023-07-08 16:56:51 +00:00 committed by GitHub
commit 4d43509423
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GPG key ID: 4AEE18F83AFDEB23
10 changed files with 165 additions and 70 deletions
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8
changelog/unreleased/issue-4375 Normal file
View file

@ -0,0 +1,8 @@
Enhancement: Add support for extended attributes on symlinks
Restic now supports extended attributes on symlinks when backing up,
restoring, or FUSE-mounting snapshots. This includes, for example, the
`security.selinux` xattr on Linux distributions that use SELinux.
https://github.com/restic/restic/issues/4375
https://github.com/restic/restic/pull/4379

13
internal/fuse/dir.go
View file

@ -222,19 +222,10 @@ func (d *dir) Lookup(ctx context.Context, name string) (fs.Node, error) {
}
func (d *dir) Listxattr(_ context.Context, req *fuse.ListxattrRequest, resp *fuse.ListxattrResponse) error {
debug.Log("Listxattr(%v, %v)", d.node.Name, req.Size)
for _, attr := range d.node.ExtendedAttributes {
resp.Append(attr.Name)
}
nodeToXattrList(d.node, req, resp)
return nil
}
func (d *dir) Getxattr(_ context.Context, req *fuse.GetxattrRequest, resp *fuse.GetxattrResponse) error {
debug.Log("Getxattr(%v, %v, %v)", d.node.Name, req.Name, req.Size)
attrval := d.node.GetExtendedAttribute(req.Name)
if attrval != nil {
resp.Xattr = attrval
return nil
}
return fuse.ErrNoXattr
return nodeGetXattr(d.node, req, resp)
}

13
internal/fuse/file.go
View file

@ -167,19 +167,10 @@ func (f *openFile) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.R
}
func (f *file) Listxattr(_ context.Context, req *fuse.ListxattrRequest, resp *fuse.ListxattrResponse) error {
debug.Log("Listxattr(%v, %v)", f.node.Name, req.Size)
for _, attr := range f.node.ExtendedAttributes {
resp.Append(attr.Name)
}
nodeToXattrList(f.node, req, resp)
return nil
}
func (f *file) Getxattr(_ context.Context, req *fuse.GetxattrRequest, resp *fuse.GetxattrResponse) error {
debug.Log("Getxattr(%v, %v, %v)", f.node.Name, req.Name, req.Size)
attrval := f.node.GetExtendedAttribute(req.Name)
if attrval != nil {
resp.Xattr = attrval
return nil
}
return fuse.ErrNoXattr
return nodeGetXattr(f.node, req, resp)
}

25
internal/fuse/fuse_test.go
View file

@ -271,6 +271,31 @@ func TestInodeFromNode(t *testing.T) {
rtest.Assert(t, inoA != inoAbb, "inode(a/b/b) = inode(a)")
}
func TestLink(t *testing.T) {
node := &restic.Node{Name: "foo.txt", Type: "symlink", Links: 1, LinkTarget: "dst", ExtendedAttributes: []restic.ExtendedAttribute{
{Name: "foo", Value: []byte("bar")},
}}
lnk, err := newLink(&Root{}, 42, node)
rtest.OK(t, err)
target, err := lnk.Readlink(context.TODO(), nil)
rtest.OK(t, err)
rtest.Equals(t, node.LinkTarget, target)
exp := &fuse.ListxattrResponse{}
exp.Append("foo")
resp := &fuse.ListxattrResponse{}
rtest.OK(t, lnk.Listxattr(context.TODO(), &fuse.ListxattrRequest{}, resp))
rtest.Equals(t, exp.Xattr, resp.Xattr)
getResp := &fuse.GetxattrResponse{}
rtest.OK(t, lnk.Getxattr(context.TODO(), &fuse.GetxattrRequest{Name: "foo"}, getResp))
rtest.Equals(t, node.ExtendedAttributes[0].Value, getResp.Xattr)
err = lnk.Getxattr(context.TODO(), &fuse.GetxattrRequest{Name: "invalid"}, nil)
rtest.Assert(t, err != nil, "missing error on reading invalid xattr")
}
var sink uint64
func BenchmarkInode(b *testing.B) {

9
internal/fuse/link.go
View file

@ -46,3 +46,12 @@ func (l *link) Attr(_ context.Context, a *fuse.Attr) error {
return nil
}
func (l *link) Listxattr(_ context.Context, req *fuse.ListxattrRequest, resp *fuse.ListxattrResponse) error {
nodeToXattrList(l.node, req, resp)
return nil
}
func (l *link) Getxattr(_ context.Context, req *fuse.GetxattrRequest, resp *fuse.GetxattrResponse) error {
return nodeGetXattr(l.node, req, resp)
}

24
internal/fuse/xattr.go Normal file
View file

@ -0,0 +1,24 @@
package fuse
import (
"github.com/anacrolix/fuse"
"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/restic"
)
func nodeToXattrList(node *restic.Node, req *fuse.ListxattrRequest, resp *fuse.ListxattrResponse) {
debug.Log("Listxattr(%v, %v)", node.Name, req.Size)
for _, attr := range node.ExtendedAttributes {
resp.Append(attr.Name)
}
}
func nodeGetXattr(node *restic.Node, req *fuse.GetxattrRequest, resp *fuse.GetxattrResponse) error {
debug.Log("Getxattr(%v, %v, %v)", node.Name, req.Name, req.Size)
attrval := node.GetExtendedAttribute(req.Name)
if attrval != nil {
resp.Xattr = attrval
return nil
}
return fuse.ErrNoXattr
}

4
internal/restic/node.go
View file

@ -609,10 +609,6 @@ func (node *Node) fillExtra(path string, fi os.FileInfo) error {
}
func (node *Node) fillExtendedAttributes(path string) error {
if node.Type == "symlink" {
return nil
}
xattrs, err := Listxattr(path)
debug.Log("fillExtendedAttributes(%v) %v %v", path, xattrs, err)
if err != nil {

64
internal/restic/node_test.go
View file

@ -4,6 +4,7 @@ import (
"context"
"os"
"path/filepath"
"reflect"
"runtime"
"testing"
"time"
@ -163,22 +164,57 @@ var nodeTests = []restic.Node{
AccessTime: parseTime("2005-05-14 21:07:04.222"),
ChangeTime: parseTime("2005-05-14 21:07:05.333"),
},
{
Name: "testXattrFile",
Type: "file",
Content: restic.IDs{},
UID: uint32(os.Getuid()),
GID: uint32(os.Getgid()),
Mode: 0604,
ModTime: parseTime("2005-05-14 21:07:03.111"),
AccessTime: parseTime("2005-05-14 21:07:04.222"),
ChangeTime: parseTime("2005-05-14 21:07:05.333"),
ExtendedAttributes: []restic.ExtendedAttribute{
{"user.foo", []byte("bar")},
},
},
{
Name: "testXattrDir",
Type: "dir",
Subtree: nil,
UID: uint32(os.Getuid()),
GID: uint32(os.Getgid()),
Mode: 0750 | os.ModeDir,
ModTime: parseTime("2005-05-14 21:07:03.111"),
AccessTime: parseTime("2005-05-14 21:07:04.222"),
ChangeTime: parseTime("2005-05-14 21:07:05.333"),
ExtendedAttributes: []restic.ExtendedAttribute{
{"user.foo", []byte("bar")},
},
},
}
func TestNodeRestoreAt(t *testing.T) {
tempdir, err := os.MkdirTemp(rtest.TestTempDir, "restic-test-")
rtest.OK(t, err)
defer func() {
if rtest.TestCleanupTempDirs {
rtest.RemoveAll(t, tempdir)
} else {
t.Logf("leaving tempdir at %v", tempdir)
}
}()
tempdir := t.TempDir()
for _, test := range nodeTests {
nodePath := filepath.Join(tempdir, test.Name)
t.Run("", func(t *testing.T) {
var nodePath string
if test.ExtendedAttributes != nil {
if runtime.GOOS == "windows" {
// restic does not support xattrs on windows
return
}
// tempdir might be backed by a filesystem that does not support
// extended attributes
nodePath = test.Name
defer func() {
_ = os.Remove(nodePath)
}()
} else {
nodePath = filepath.Join(tempdir, test.Name)
}
rtest.OK(t, test.CreateAt(context.TODO(), nodePath, nil))
rtest.OK(t, test.RestoreMetadata(nodePath))
@ -215,6 +251,12 @@ func TestNodeRestoreAt(t *testing.T) {
AssertFsTimeEqual(t, "AccessTime", test.Type, test.AccessTime, n2.AccessTime)
AssertFsTimeEqual(t, "ModTime", test.Type, test.ModTime, n2.ModTime)
if len(n2.ExtendedAttributes) == 0 {
n2.ExtendedAttributes = nil
}
rtest.Assert(t, reflect.DeepEqual(test.ExtendedAttributes, n2.ExtendedAttributes),
"%v: xattrs don't match (%v != %v)", test.Name, test.ExtendedAttributes, n2.ExtendedAttributes)
})
}
}

13
internal/restic/node_unix_test.go
View file

@ -5,10 +5,13 @@ package restic
import (
"os"
"path/filepath"
"runtime"
"syscall"
"testing"
"time"
rtest "github.com/restic/restic/internal/test"
)
func stat(t testing.TB, filename string) (fi os.FileInfo, ok bool) {
@ -25,6 +28,7 @@ func stat(t testing.TB, filename string) (fi os.FileInfo, ok bool) {
}
func checkFile(t testing.TB, stat *syscall.Stat_t, node *Node) {
t.Helper()
if uint32(node.Mode.Perm()) != uint32(stat.Mode&0777) {
t.Errorf("Mode does not match, want %v, got %v", stat.Mode&0777, node.Mode)
}
@ -37,7 +41,7 @@ func checkFile(t testing.TB, stat *syscall.Stat_t, node *Node) {
t.Errorf("Dev does not match, want %v, got %v", stat.Dev, node.DeviceID)
}
if node.Size != uint64(stat.Size) {
if node.Size != uint64(stat.Size) && node.Type != "symlink" {
t.Errorf("Size does not match, want %v, got %v", stat.Size, node.Size)
}
@ -83,6 +87,10 @@ func checkDevice(t testing.TB, stat *syscall.Stat_t, node *Node) {
}
func TestNodeFromFileInfo(t *testing.T) {
tmp := t.TempDir()
symlink := filepath.Join(tmp, "symlink")
rtest.OK(t, os.Symlink("target", symlink))
type Test struct {
filename string
canSkip bool
@ -90,6 +98,7 @@ func TestNodeFromFileInfo(t *testing.T) {
var tests = []Test{
{"node_test.go", false},
{"/dev/sda", true},
{symlink, false},
}
// on darwin, users are not permitted to list the extended attributes of
@ -125,7 +134,7 @@ func TestNodeFromFileInfo(t *testing.T) {
}
switch node.Type {
case "file":
case "file", "symlink":
checkFile(t, s, node)
case "dev", "chardev":
checkFile(t, s, node)

6
internal/restic/node_xattr.go
View file

@ -13,20 +13,20 @@ import (
// Getxattr retrieves extended attribute data associated with path.
func Getxattr(path, name string) ([]byte, error) {
b, err := xattr.Get(path, name)
b, err := xattr.LGet(path, name)
return b, handleXattrErr(err)
}
// Listxattr retrieves a list of names of extended attributes associated with the
// given path in the file system.
func Listxattr(path string) ([]string, error) {
l, err := xattr.List(path)
l, err := xattr.LList(path)
return l, handleXattrErr(err)
}
// Setxattr associates name and data together as an attribute of path.
func Setxattr(path, name string, data []byte) error {
return handleXattrErr(xattr.Set(path, name, data))
return handleXattrErr(xattr.LSet(path, name, data))
}
func handleXattrErr(err error) error {