mirror of
https://github.com/restic/restic.git
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484 lines
17 KiB
Go
484 lines
17 KiB
Go
package fs
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import (
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"encoding/json"
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"fmt"
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"path/filepath"
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"reflect"
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"strings"
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"sync"
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"syscall"
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"unsafe"
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"github.com/restic/restic/internal/debug"
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"github.com/restic/restic/internal/errors"
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"github.com/restic/restic/internal/restic"
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"golang.org/x/sys/windows"
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)
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var (
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modAdvapi32 = syscall.NewLazyDLL("advapi32.dll")
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procEncryptFile = modAdvapi32.NewProc("EncryptFileW")
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procDecryptFile = modAdvapi32.NewProc("DecryptFileW")
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// eaSupportedVolumesMap is a map of volumes to boolean values indicating if they support extended attributes.
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eaSupportedVolumesMap = sync.Map{}
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)
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const (
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extendedPathPrefix = `\\?\`
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uncPathPrefix = `\\?\UNC\`
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globalRootPrefix = `\\?\GLOBALROOT\`
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volumeGUIDPrefix = `\\?\Volume{`
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)
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// mknod is not supported on Windows.
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func mknod(_ string, _ uint32, _ uint64) (err error) {
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return errors.New("device nodes cannot be created on windows")
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}
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// Windows doesn't need lchown
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func lchown(_ string, _ int, _ int) (err error) {
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return nil
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}
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// utimesNano is like syscall.UtimesNano, except that it sets FILE_FLAG_OPEN_REPARSE_POINT.
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func utimesNano(path string, atime, mtime int64, _ restic.NodeType) error {
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// tweaked version of UtimesNano from go/src/syscall/syscall_windows.go
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pathp, e := syscall.UTF16PtrFromString(fixpath(path))
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if e != nil {
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return e
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}
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h, e := syscall.CreateFile(pathp,
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syscall.FILE_WRITE_ATTRIBUTES, syscall.FILE_SHARE_WRITE, nil, syscall.OPEN_EXISTING,
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syscall.FILE_FLAG_BACKUP_SEMANTICS|syscall.FILE_FLAG_OPEN_REPARSE_POINT, 0)
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if e != nil {
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return e
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}
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defer func() {
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err := syscall.Close(h)
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if err != nil {
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debug.Log("Error closing file handle for %s: %v\n", path, err)
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}
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}()
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a := syscall.NsecToFiletime(atime)
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w := syscall.NsecToFiletime(mtime)
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return syscall.SetFileTime(h, nil, &a, &w)
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}
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// restore extended attributes for windows
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func nodeRestoreExtendedAttributes(node *restic.Node, path string) (err error) {
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count := len(node.ExtendedAttributes)
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if count > 0 {
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eas := make([]extendedAttribute, count)
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for i, attr := range node.ExtendedAttributes {
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eas[i] = extendedAttribute{Name: attr.Name, Value: attr.Value}
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}
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if errExt := restoreExtendedAttributes(node.Type, path, eas); errExt != nil {
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return errExt
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}
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}
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return nil
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}
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// fill extended attributes in the node. This also includes the Generic attributes for windows.
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func nodeFillExtendedAttributes(node *restic.Node, path string, _ bool) (err error) {
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var fileHandle windows.Handle
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if fileHandle, err = openHandleForEA(node.Type, path, false); fileHandle == 0 {
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return nil
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}
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if err != nil {
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return errors.Errorf("get EA failed while opening file handle for path %v, with: %v", path, err)
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}
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defer closeFileHandle(fileHandle, path) // Replaced inline defer with named function call
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//Get the windows Extended Attributes using the file handle
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var extAtts []extendedAttribute
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extAtts, err = fgetEA(fileHandle)
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debug.Log("fillExtendedAttributes(%v) %v", path, extAtts)
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if err != nil {
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return errors.Errorf("get EA failed for path %v, with: %v", path, err)
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}
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if len(extAtts) == 0 {
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return nil
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}
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//Fill the ExtendedAttributes in the node using the name/value pairs in the windows EA
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for _, attr := range extAtts {
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extendedAttr := restic.ExtendedAttribute{
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Name: attr.Name,
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Value: attr.Value,
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}
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node.ExtendedAttributes = append(node.ExtendedAttributes, extendedAttr)
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}
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return nil
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}
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// closeFileHandle safely closes a file handle and logs any errors.
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func closeFileHandle(fileHandle windows.Handle, path string) {
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err := windows.CloseHandle(fileHandle)
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if err != nil {
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debug.Log("Error closing file handle for %s: %v\n", path, err)
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}
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}
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// restoreExtendedAttributes handles restore of the Windows Extended Attributes to the specified path.
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// The Windows API requires setting of all the Extended Attributes in one call.
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func restoreExtendedAttributes(nodeType restic.NodeType, path string, eas []extendedAttribute) (err error) {
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var fileHandle windows.Handle
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if fileHandle, err = openHandleForEA(nodeType, path, true); fileHandle == 0 {
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return nil
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}
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if err != nil {
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return errors.Errorf("set EA failed while opening file handle for path %v, with: %v", path, err)
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}
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defer closeFileHandle(fileHandle, path) // Replaced inline defer with named function call
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// clear old unexpected xattrs by setting them to an empty value
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oldEAs, err := fgetEA(fileHandle)
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if err != nil {
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return err
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}
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for _, oldEA := range oldEAs {
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found := false
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for _, ea := range eas {
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if strings.EqualFold(ea.Name, oldEA.Name) {
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found = true
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break
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}
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}
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if !found {
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eas = append(eas, extendedAttribute{Name: oldEA.Name, Value: nil})
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}
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}
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if err = fsetEA(fileHandle, eas); err != nil {
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return errors.Errorf("set EA failed for path %v, with: %v", path, err)
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}
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return nil
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}
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// restoreGenericAttributes restores generic attributes for Windows
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func nodeRestoreGenericAttributes(node *restic.Node, path string, warn func(msg string)) (err error) {
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if len(node.GenericAttributes) == 0 {
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return nil
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}
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var errs []error
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windowsAttributes, unknownAttribs, err := genericAttributesToWindowsAttrs(node.GenericAttributes)
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if err != nil {
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return fmt.Errorf("error parsing generic attribute for: %s : %v", path, err)
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}
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if windowsAttributes.CreationTime != nil {
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if err := restoreCreationTime(path, windowsAttributes.CreationTime); err != nil {
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errs = append(errs, fmt.Errorf("error restoring creation time for: %s : %v", path, err))
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}
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}
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if windowsAttributes.FileAttributes != nil {
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if err := restoreFileAttributes(path, windowsAttributes.FileAttributes); err != nil {
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errs = append(errs, fmt.Errorf("error restoring file attributes for: %s : %v", path, err))
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}
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}
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if windowsAttributes.SecurityDescriptor != nil {
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if err := setSecurityDescriptor(path, windowsAttributes.SecurityDescriptor); err != nil {
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errs = append(errs, fmt.Errorf("error restoring security descriptor for: %s : %v", path, err))
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}
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}
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restic.HandleUnknownGenericAttributesFound(unknownAttribs, warn)
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return errors.Join(errs...)
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}
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// genericAttributesToWindowsAttrs converts the generic attributes map to a WindowsAttributes and also returns a string of unknown attributes that it could not convert.
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func genericAttributesToWindowsAttrs(attrs map[restic.GenericAttributeType]json.RawMessage) (windowsAttributes restic.WindowsAttributes, unknownAttribs []restic.GenericAttributeType, err error) {
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waValue := reflect.ValueOf(&windowsAttributes).Elem()
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unknownAttribs, err = restic.GenericAttributesToOSAttrs(attrs, reflect.TypeOf(windowsAttributes), &waValue, "windows")
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return windowsAttributes, unknownAttribs, err
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}
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// restoreCreationTime gets the creation time from the data and sets it to the file/folder at
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// the specified path.
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func restoreCreationTime(path string, creationTime *syscall.Filetime) (err error) {
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pathPointer, err := syscall.UTF16PtrFromString(fixpath(path))
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if err != nil {
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return err
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}
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handle, err := syscall.CreateFile(pathPointer,
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syscall.FILE_WRITE_ATTRIBUTES, syscall.FILE_SHARE_WRITE, nil,
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syscall.OPEN_EXISTING, syscall.FILE_FLAG_BACKUP_SEMANTICS, 0)
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if err != nil {
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return err
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}
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defer func() {
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if err := syscall.Close(handle); err != nil {
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debug.Log("Error closing file handle for %s: %v\n", path, err)
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}
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}()
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return syscall.SetFileTime(handle, creationTime, nil, nil)
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}
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// restoreFileAttributes gets the File Attributes from the data and sets them to the file/folder
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// at the specified path.
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func restoreFileAttributes(path string, fileAttributes *uint32) (err error) {
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pathPointer, err := syscall.UTF16PtrFromString(fixpath(path))
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if err != nil {
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return err
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}
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err = fixEncryptionAttribute(path, fileAttributes, pathPointer)
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if err != nil {
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debug.Log("Could not change encryption attribute for path: %s: %v", path, err)
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}
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return syscall.SetFileAttributes(pathPointer, *fileAttributes)
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}
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// fixEncryptionAttribute checks if a file needs to be marked encrypted and is not already encrypted, it sets
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// the FILE_ATTRIBUTE_ENCRYPTED. Conversely, if the file needs to be marked unencrypted and it is already
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// marked encrypted, it removes the FILE_ATTRIBUTE_ENCRYPTED.
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func fixEncryptionAttribute(path string, attrs *uint32, pathPointer *uint16) (err error) {
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if *attrs&windows.FILE_ATTRIBUTE_ENCRYPTED != 0 {
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// File should be encrypted.
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err = encryptFile(pathPointer)
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if err != nil {
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if IsAccessDenied(err) || errors.Is(err, windows.ERROR_FILE_READ_ONLY) {
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// If existing file already has readonly or system flag, encrypt file call fails.
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// The readonly and system flags will be set again at the end of this func if they are needed.
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err = ResetPermissions(path)
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if err != nil {
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return fmt.Errorf("failed to encrypt file: failed to reset permissions: %s : %v", path, err)
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}
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err = clearSystem(path)
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if err != nil {
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return fmt.Errorf("failed to encrypt file: failed to clear system flag: %s : %v", path, err)
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}
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err = encryptFile(pathPointer)
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if err != nil {
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return fmt.Errorf("failed retry to encrypt file: %s : %v", path, err)
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}
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} else {
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return fmt.Errorf("failed to encrypt file: %s : %v", path, err)
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}
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}
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} else {
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existingAttrs, err := windows.GetFileAttributes(pathPointer)
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if err != nil {
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return fmt.Errorf("failed to get file attributes for existing file: %s : %v", path, err)
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}
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if existingAttrs&windows.FILE_ATTRIBUTE_ENCRYPTED != 0 {
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// File should not be encrypted, but its already encrypted. Decrypt it.
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err = decryptFile(pathPointer)
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if err != nil {
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if IsAccessDenied(err) || errors.Is(err, windows.ERROR_FILE_READ_ONLY) {
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// If existing file already has readonly or system flag, decrypt file call fails.
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// The readonly and system flags will be set again after this func if they are needed.
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err = ResetPermissions(path)
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if err != nil {
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return fmt.Errorf("failed to encrypt file: failed to reset permissions: %s : %v", path, err)
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}
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err = clearSystem(path)
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if err != nil {
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return fmt.Errorf("failed to decrypt file: failed to clear system flag: %s : %v", path, err)
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}
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err = decryptFile(pathPointer)
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if err != nil {
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return fmt.Errorf("failed retry to decrypt file: %s : %v", path, err)
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}
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} else {
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return fmt.Errorf("failed to decrypt file: %s : %v", path, err)
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}
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}
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}
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}
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return err
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}
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// encryptFile set the encrypted flag on the file.
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func encryptFile(pathPointer *uint16) error {
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// Call EncryptFile function
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ret, _, err := procEncryptFile.Call(uintptr(unsafe.Pointer(pathPointer)))
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if ret == 0 {
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return err
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}
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return nil
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}
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// decryptFile removes the encrypted flag from the file.
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func decryptFile(pathPointer *uint16) error {
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// Call DecryptFile function
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ret, _, err := procDecryptFile.Call(uintptr(unsafe.Pointer(pathPointer)))
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if ret == 0 {
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return err
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}
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return nil
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}
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// nodeFillGenericAttributes fills in the generic attributes for windows like File Attributes,
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// Created time and Security Descriptors.
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// It also checks if the volume supports extended attributes and stores the result in a map
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// so that it does not have to be checked again for subsequent calls for paths in the same volume.
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func nodeFillGenericAttributes(node *restic.Node, path string, stat *ExtendedFileInfo) (allowExtended bool, err error) {
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if strings.Contains(filepath.Base(path), ":") {
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// Do not process for Alternate Data Streams in Windows
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// Also do not allow processing of extended attributes for ADS.
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return false, nil
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}
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isVolume, err := isVolumePath(path)
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if err != nil {
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return false, err
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}
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if isVolume {
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// Do not process file attributes, created time and sd for windows root volume paths
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// Security descriptors are not supported for root volume paths.
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// Though file attributes and created time are supported for root volume paths,
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// we ignore them and we do not want to replace them during every restore.
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allowExtended, err = checkAndStoreEASupport(path)
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if err != nil {
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return false, err
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}
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return allowExtended, err
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}
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var sd *[]byte
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if node.Type == restic.NodeTypeFile || node.Type == restic.NodeTypeDir {
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// Check EA support and get security descriptor for file/dir only
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allowExtended, err = checkAndStoreEASupport(path)
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if err != nil {
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return false, err
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}
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if sd, err = getSecurityDescriptor(path); err != nil {
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return allowExtended, err
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}
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}
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winFI := stat.Sys().(*syscall.Win32FileAttributeData)
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// Add Windows attributes
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node.GenericAttributes, err = restic.WindowsAttrsToGenericAttributes(restic.WindowsAttributes{
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CreationTime: &winFI.CreationTime,
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FileAttributes: &winFI.FileAttributes,
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SecurityDescriptor: sd,
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})
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return allowExtended, err
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}
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// checkAndStoreEASupport checks if the volume of the path supports extended attributes and stores the result in a map
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// If the result is already in the map, it returns the result from the map.
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func checkAndStoreEASupport(path string) (isEASupportedVolume bool, err error) {
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var volumeName string
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volumeName, err = prepareVolumeName(path)
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if err != nil {
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return false, err
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}
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if volumeName != "" {
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// First check if the manually prepared volume name is already in the map
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eaSupportedValue, exists := eaSupportedVolumesMap.Load(volumeName)
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if exists {
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// Cache hit, immediately return the cached value
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return eaSupportedValue.(bool), nil
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}
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// If not found, check if EA is supported with manually prepared volume name
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isEASupportedVolume, err = pathSupportsExtendedAttributes(volumeName + `\`)
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// If the prepared volume name is not valid, we will fetch the actual volume name next.
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if err != nil && !errors.Is(err, windows.DNS_ERROR_INVALID_NAME) {
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debug.Log("Error checking if extended attributes are supported for prepared volume name %s: %v", volumeName, err)
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// There can be multiple errors like path does not exist, bad network path, etc.
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// We just gracefully disallow extended attributes for cases.
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return false, nil
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}
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}
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// If an entry is not found, get the actual volume name
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volumeNameActual, err := getVolumePathName(path)
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if err != nil {
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debug.Log("Error getting actual volume name %s for path %s: %v", volumeName, path, err)
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// There can be multiple errors like path does not exist, bad network path, etc.
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// We just gracefully disallow extended attributes for cases.
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return false, nil
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}
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if volumeNameActual != volumeName {
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// If the actual volume name is different, check cache for the actual volume name
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eaSupportedValue, exists := eaSupportedVolumesMap.Load(volumeNameActual)
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if exists {
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// Cache hit, immediately return the cached value
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return eaSupportedValue.(bool), nil
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}
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// If the actual volume name is different and is not in the map, again check if the new volume supports extended attributes with the actual volume name
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isEASupportedVolume, err = pathSupportsExtendedAttributes(volumeNameActual + `\`)
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// Debug log for cases where the prepared volume name is not valid
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if err != nil {
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debug.Log("Error checking if extended attributes are supported for actual volume name %s: %v", volumeNameActual, err)
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// There can be multiple errors like path does not exist, bad network path, etc.
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// We just gracefully disallow extended attributes for cases.
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return false, nil
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} else {
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debug.Log("Checking extended attributes. Prepared volume name: %s, actual volume name: %s, isEASupportedVolume: %v, err: %v", volumeName, volumeNameActual, isEASupportedVolume, err)
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}
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}
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if volumeNameActual != "" {
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eaSupportedVolumesMap.Store(volumeNameActual, isEASupportedVolume)
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}
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return isEASupportedVolume, err
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}
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// getVolumePathName returns the volume path name for the given path.
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func getVolumePathName(path string) (volumeName string, err error) {
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utf16Path, err := windows.UTF16PtrFromString(path)
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if err != nil {
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return "", err
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}
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// Get the volume path (e.g., "D:")
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var volumePath [windows.MAX_PATH + 1]uint16
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err = windows.GetVolumePathName(utf16Path, &volumePath[0], windows.MAX_PATH+1)
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if err != nil {
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return "", err
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}
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// Trim any trailing backslashes
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volumeName = strings.TrimRight(windows.UTF16ToString(volumePath[:]), "\\")
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return volumeName, nil
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}
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// isVolumePath returns whether a path refers to a volume
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func isVolumePath(path string) (bool, error) {
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volName, err := prepareVolumeName(path)
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if err != nil {
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return false, err
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}
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cleanPath := filepath.Clean(path)
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cleanVolume := filepath.Clean(volName + `\`)
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return cleanPath == cleanVolume, nil
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}
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// prepareVolumeName prepares the volume name for different cases in Windows
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func prepareVolumeName(path string) (volumeName string, err error) {
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// Check if it's an extended length path
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if strings.HasPrefix(path, globalRootPrefix) {
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// Extract the VSS snapshot volume name eg. `\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopyXX`
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if parts := strings.SplitN(path, `\`, 7); len(parts) >= 6 {
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volumeName = strings.Join(parts[:6], `\`)
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} else {
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volumeName = filepath.VolumeName(path)
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}
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} else {
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if !strings.HasPrefix(path, volumeGUIDPrefix) { // Handle volume GUID path
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if strings.HasPrefix(path, uncPathPrefix) {
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// Convert \\?\UNC\ extended path to standard path to get the volume name correctly
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path = `\\` + path[len(uncPathPrefix):]
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} else if strings.HasPrefix(path, extendedPathPrefix) {
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//Extended length path prefix needs to be trimmed to get the volume name correctly
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path = path[len(extendedPathPrefix):]
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} else {
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// Use the absolute path
|
|
path, err = filepath.Abs(path)
|
|
if err != nil {
|
|
return "", fmt.Errorf("failed to get absolute path: %w", err)
|
|
}
|
|
}
|
|
}
|
|
volumeName = filepath.VolumeName(path)
|
|
}
|
|
return volumeName, nil
|
|
}
|