diff --git a/backend/local/lchmod.go b/backend/local/lchmod.go new file mode 100644 index 000000000..823718dfe --- /dev/null +++ b/backend/local/lchmod.go @@ -0,0 +1,16 @@ +//go:build windows || plan9 || js || linux + +package local + +import "os" + +const haveLChmod = false + +// lChmod changes the mode of the named file to mode. If the file is a symbolic +// link, it changes the link, not the target. If there is an error, +// it will be of type *PathError. +func lChmod(name string, mode os.FileMode) error { + // Can't do this safely on this OS - chmoding a symlink always + // changes the destination. + return nil +} diff --git a/backend/local/lchmod_unix.go b/backend/local/lchmod_unix.go new file mode 100644 index 000000000..f1fdc4745 --- /dev/null +++ b/backend/local/lchmod_unix.go @@ -0,0 +1,41 @@ +//go:build !windows && !plan9 && !js && !linux + +package local + +import ( + "os" + "syscall" + + "golang.org/x/sys/unix" +) + +const haveLChmod = true + +// syscallMode returns the syscall-specific mode bits from Go's portable mode bits. +// +// Borrowed from the syscall source since it isn't public. +func syscallMode(i os.FileMode) (o uint32) { + o |= uint32(i.Perm()) + if i&os.ModeSetuid != 0 { + o |= syscall.S_ISUID + } + if i&os.ModeSetgid != 0 { + o |= syscall.S_ISGID + } + if i&os.ModeSticky != 0 { + o |= syscall.S_ISVTX + } + return o +} + +// lChmod changes the mode of the named file to mode. If the file is a symbolic +// link, it changes the link, not the target. If there is an error, +// it will be of type *PathError. +func lChmod(name string, mode os.FileMode) error { + // NB linux does not support AT_SYMLINK_NOFOLLOW as a parameter to fchmodat + // and returns ENOTSUP if you try, so we don't support this on linux + if e := unix.Fchmodat(unix.AT_FDCWD, name, syscallMode(mode), unix.AT_SYMLINK_NOFOLLOW); e != nil { + return &os.PathError{Op: "lChmod", Path: name, Err: e} + } + return nil +} diff --git a/backend/local/lchtimes.go b/backend/local/lchtimes.go index c8f03ef46..fcabdcc34 100644 --- a/backend/local/lchtimes.go +++ b/backend/local/lchtimes.go @@ -1,4 +1,4 @@ -//go:build windows || plan9 || js +//go:build plan9 || js package local diff --git a/backend/local/lchtimes_windows.go b/backend/local/lchtimes_windows.go new file mode 100644 index 000000000..a6dec9a12 --- /dev/null +++ b/backend/local/lchtimes_windows.go @@ -0,0 +1,19 @@ +//go:build windows + +package local + +import ( + "time" +) + +const haveLChtimes = true + +// lChtimes changes the access and modification times of the named +// link, similar to the Unix utime() or utimes() functions. +// +// The underlying filesystem may truncate or round the values to a +// less precise time unit. +// If there is an error, it will be of type *PathError. +func lChtimes(name string, atime time.Time, mtime time.Time) error { + return setTimes(name, atime, mtime, time.Time{}, true) +} diff --git a/backend/local/local_internal_test.go b/backend/local/local_internal_test.go index ea0fdc765..b3b9b8ba1 100644 --- a/backend/local/local_internal_test.go +++ b/backend/local/local_internal_test.go @@ -268,22 +268,66 @@ func TestMetadata(t *testing.T) { r := fstest.NewRun(t) const filePath = "metafile.txt" when := time.Now() - const dayLength = len("2001-01-01") - whenRFC := when.Format(time.RFC3339Nano) r.WriteFile(filePath, "metadata file contents", when) f := r.Flocal.(*Fs) + // Set fs into "-l" / "--links" mode + f.opt.TranslateSymlinks = true + + // Write a symlink to the file + symlinkPath := "metafile-link.txt" + osSymlinkPath := filepath.Join(f.root, symlinkPath) + symlinkPath += linkSuffix + require.NoError(t, os.Symlink(filePath, osSymlinkPath)) + symlinkModTime := fstest.Time("2002-02-03T04:05:10.123123123Z") + require.NoError(t, lChtimes(osSymlinkPath, symlinkModTime, symlinkModTime)) + // Get the object obj, err := f.NewObject(ctx, filePath) require.NoError(t, err) o := obj.(*Object) + // Get the symlink object + symlinkObj, err := f.NewObject(ctx, symlinkPath) + require.NoError(t, err) + symlinkO := symlinkObj.(*Object) + + // Record metadata for o + oMeta, err := o.Metadata(ctx) + require.NoError(t, err) + + // Test symlink first to check it doesn't mess up file + t.Run("Symlink", func(t *testing.T) { + testMetadata(t, r, symlinkO, symlinkModTime) + }) + + // Read it again + oMetaNew, err := o.Metadata(ctx) + require.NoError(t, err) + + // Check that operating on the symlink didn't change the file it was pointing to + // See: https://github.com/rclone/rclone/security/advisories/GHSA-hrxh-9w67-g4cv + assert.Equal(t, oMeta, oMetaNew, "metadata setting on symlink messed up file") + + // Now run the same tests on the file + t.Run("File", func(t *testing.T) { + testMetadata(t, r, o, when) + }) +} + +func testMetadata(t *testing.T, r *fstest.Run, o *Object, when time.Time) { + ctx := context.Background() + whenRFC := when.Format(time.RFC3339Nano) + const dayLength = len("2001-01-01") + + f := r.Flocal.(*Fs) features := f.Features() - var hasXID, hasAtime, hasBtime bool + var hasXID, hasAtime, hasBtime, canSetXattrOnLinks bool switch runtime.GOOS { case "darwin", "freebsd", "netbsd", "linux": hasXID, hasAtime, hasBtime = true, true, true + canSetXattrOnLinks = runtime.GOOS != "linux" case "openbsd", "solaris": hasXID, hasAtime = true, true case "windows": @@ -306,6 +350,10 @@ func TestMetadata(t *testing.T) { require.NoError(t, err) assert.Nil(t, m) + if !canSetXattrOnLinks && o.translatedLink { + t.Skip("Skip remainder of test as can't set xattr on symlinks on this OS") + } + inM := fs.Metadata{ "potato": "chips", "cabbage": "soup", @@ -320,18 +368,21 @@ func TestMetadata(t *testing.T) { }) checkTime := func(m fs.Metadata, key string, when time.Time) { + t.Helper() mt, ok := o.parseMetadataTime(m, key) assert.True(t, ok) dt := mt.Sub(when) precision := time.Second - assert.True(t, dt >= -precision && dt <= precision, fmt.Sprintf("%s: dt %v outside +/- precision %v", key, dt, precision)) + assert.True(t, dt >= -precision && dt <= precision, fmt.Sprintf("%s: dt %v outside +/- precision %v want %v got %v", key, dt, precision, mt, when)) } checkInt := func(m fs.Metadata, key string, base int) int { + t.Helper() value, ok := o.parseMetadataInt(m, key, base) assert.True(t, ok) return value } + t.Run("Read", func(t *testing.T) { m, err := o.Metadata(ctx) require.NoError(t, err) @@ -341,13 +392,12 @@ func TestMetadata(t *testing.T) { checkInt(m, "mode", 8) checkTime(m, "mtime", when) - assert.Equal(t, len(whenRFC), len(m["mtime"])) assert.Equal(t, whenRFC[:dayLength], m["mtime"][:dayLength]) - if hasAtime { + if hasAtime && !o.translatedLink { // symlinks generally don't record atime checkTime(m, "atime", when) } - if hasBtime { + if hasBtime && !o.translatedLink { // symlinks generally don't record btime checkTime(m, "btime", when) } if hasXID { @@ -371,6 +421,10 @@ func TestMetadata(t *testing.T) { "mode": "0767", "potato": "wedges", } + if !canSetXattrOnLinks && o.translatedLink { + // Don't change xattr if not supported on symlinks + delete(newM, "potato") + } err := o.writeMetadata(newM) require.NoError(t, err) @@ -380,7 +434,11 @@ func TestMetadata(t *testing.T) { mode := checkInt(m, "mode", 8) if runtime.GOOS != "windows" { - assert.Equal(t, 0767, mode&0777, fmt.Sprintf("mode wrong - expecting 0767 got 0%o", mode&0777)) + expectedMode := 0767 + if o.translatedLink && runtime.GOOS == "linux" { + expectedMode = 0777 // perms of symlinks always read as 0777 on linux + } + assert.Equal(t, expectedMode, mode&0777, fmt.Sprintf("mode wrong - expecting 0%o got 0%o", expectedMode, mode&0777)) } checkTime(m, "mtime", newMtime) @@ -390,7 +448,7 @@ func TestMetadata(t *testing.T) { if haveSetBTime { checkTime(m, "btime", newBtime) } - if xattrSupported { + if xattrSupported && (canSetXattrOnLinks || !o.translatedLink) { assert.Equal(t, "wedges", m["potato"]) } }) diff --git a/backend/local/metadata.go b/backend/local/metadata.go index 7ab69af30..75b195e64 100644 --- a/backend/local/metadata.go +++ b/backend/local/metadata.go @@ -105,7 +105,11 @@ func (o *Object) writeMetadataToFile(m fs.Metadata) (outErr error) { } if haveSetBTime { if btimeOK { - err = setBTime(o.path, btime) + if o.translatedLink { + err = lsetBTime(o.path, btime) + } else { + err = setBTime(o.path, btime) + } if err != nil { outErr = fmt.Errorf("failed to set birth (creation) time: %w", err) } @@ -121,7 +125,11 @@ func (o *Object) writeMetadataToFile(m fs.Metadata) (outErr error) { if runtime.GOOS == "windows" || runtime.GOOS == "plan9" { fs.Debugf(o, "Ignoring request to set ownership %o.%o on this OS", gid, uid) } else { - err = os.Chown(o.path, uid, gid) + if o.translatedLink { + err = os.Lchown(o.path, uid, gid) + } else { + err = os.Chown(o.path, uid, gid) + } if err != nil { outErr = fmt.Errorf("failed to change ownership: %w", err) } @@ -132,7 +140,16 @@ func (o *Object) writeMetadataToFile(m fs.Metadata) (outErr error) { if mode >= 0 { umode := uint(mode) if umode <= math.MaxUint32 { - err = os.Chmod(o.path, os.FileMode(umode)) + if o.translatedLink { + if haveLChmod { + err = lChmod(o.path, os.FileMode(umode)) + } else { + fs.Debugf(o, "Unable to set mode %v on a symlink on this OS", os.FileMode(umode)) + err = nil + } + } else { + err = os.Chmod(o.path, os.FileMode(umode)) + } if err != nil { outErr = fmt.Errorf("failed to change permissions: %w", err) } diff --git a/backend/local/setbtime.go b/backend/local/setbtime.go index 5c946348f..bb37b1735 100644 --- a/backend/local/setbtime.go +++ b/backend/local/setbtime.go @@ -13,3 +13,9 @@ func setBTime(name string, btime time.Time) error { // Does nothing return nil } + +// lsetBTime changes the birth time of the link passed in +func lsetBTime(name string, btime time.Time) error { + // Does nothing + return nil +} diff --git a/backend/local/setbtime_windows.go b/backend/local/setbtime_windows.go index 510a4da6a..8ae499826 100644 --- a/backend/local/setbtime_windows.go +++ b/backend/local/setbtime_windows.go @@ -9,15 +9,20 @@ import ( const haveSetBTime = true -// setBTime sets the birth time of the file passed in -func setBTime(name string, btime time.Time) (err error) { +// setTimes sets any of atime, mtime or btime +// if link is set it sets a link rather than the target +func setTimes(name string, atime, mtime, btime time.Time, link bool) (err error) { pathp, err := syscall.UTF16PtrFromString(name) if err != nil { return err } + fileFlag := uint32(syscall.FILE_FLAG_BACKUP_SEMANTICS) + if link { + fileFlag |= syscall.FILE_FLAG_OPEN_REPARSE_POINT + } h, err := syscall.CreateFile(pathp, syscall.FILE_WRITE_ATTRIBUTES, syscall.FILE_SHARE_WRITE, nil, - syscall.OPEN_EXISTING, syscall.FILE_FLAG_BACKUP_SEMANTICS, 0) + syscall.OPEN_EXISTING, fileFlag, 0) if err != nil { return err } @@ -27,6 +32,28 @@ func setBTime(name string, btime time.Time) (err error) { err = closeErr } }() - bFileTime := syscall.NsecToFiletime(btime.UnixNano()) - return syscall.SetFileTime(h, &bFileTime, nil, nil) + var patime, pmtime, pbtime *syscall.Filetime + if !atime.IsZero() { + t := syscall.NsecToFiletime(atime.UnixNano()) + patime = &t + } + if !mtime.IsZero() { + t := syscall.NsecToFiletime(mtime.UnixNano()) + pmtime = &t + } + if !btime.IsZero() { + t := syscall.NsecToFiletime(btime.UnixNano()) + pbtime = &t + } + return syscall.SetFileTime(h, pbtime, patime, pmtime) +} + +// setBTime sets the birth time of the file passed in +func setBTime(name string, btime time.Time) (err error) { + return setTimes(name, time.Time{}, time.Time{}, btime, false) +} + +// lsetBTime changes the birth time of the link passed in +func lsetBTime(name string, btime time.Time) error { + return setTimes(name, time.Time{}, time.Time{}, btime, true) }