a602e798b1
Just presenting an empty directory means that the user does not know that things went wrong unless he checks the syslog or tries to delete the directory. It would be nice to report the error even if only some files were invalid. However, go-fuse does not allow returning the valid directory entries AND an error.
291 lines
8.1 KiB
Go
291 lines
8.1 KiB
Go
package fusefrontend
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// Mkdir and Rmdir
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import (
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"fmt"
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"os"
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"path/filepath"
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"syscall"
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"github.com/hanwen/go-fuse/fuse"
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"github.com/rfjakob/gocryptfs/internal/configfile"
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"github.com/rfjakob/gocryptfs/internal/cryptocore"
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"github.com/rfjakob/gocryptfs/internal/nametransform"
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"github.com/rfjakob/gocryptfs/internal/toggledlog"
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)
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func (fs *FS) mkdirWithIv(cPath string, mode uint32) error {
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// Between the creation of the directory and the creation of gocryptfs.diriv
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// the directory is inconsistent. Take the lock to prevent other readers.
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fs.dirIVLock.Lock()
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// The new directory may take the place of an older one that is still in the cache
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fs.nameTransform.DirIVCache.Clear()
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defer fs.dirIVLock.Unlock()
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err := os.Mkdir(cPath, os.FileMode(mode))
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if err != nil {
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return err
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}
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// Create gocryptfs.diriv
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err = nametransform.WriteDirIV(cPath)
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if err != nil {
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err2 := syscall.Rmdir(cPath)
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if err2 != nil {
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toggledlog.Warn.Printf("mkdirWithIv: rollback failed: %v", err2)
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}
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}
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return err
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}
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func (fs *FS) Mkdir(newPath string, mode uint32, context *fuse.Context) (code fuse.Status) {
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if fs.isFiltered(newPath) {
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return fuse.EPERM
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}
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cPath, err := fs.getBackingPath(newPath)
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if err != nil {
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return fuse.ToStatus(err)
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}
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if !fs.args.DirIV {
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return fuse.ToStatus(os.Mkdir(cPath, os.FileMode(mode)))
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}
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// We need write and execute permissions to create gocryptfs.diriv
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origMode := mode
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mode = mode | 0300
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// Handle long file name
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cName := filepath.Base(cPath)
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if nametransform.IsLongContent(cName) {
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var dirfd *os.File
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dirfd, err = os.Open(filepath.Dir(cPath))
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if err != nil {
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return fuse.ToStatus(err)
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}
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defer dirfd.Close()
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// Create ".name"
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err = fs.nameTransform.WriteLongName(dirfd, cName, newPath)
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if err != nil {
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return fuse.ToStatus(err)
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}
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// Create directory
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err = fs.mkdirWithIv(cPath, mode)
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if err != nil {
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nametransform.DeleteLongName(dirfd, cName)
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return fuse.ToStatus(err)
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}
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} else {
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err = fs.mkdirWithIv(cPath, mode)
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if err != nil {
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return fuse.ToStatus(err)
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}
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}
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// Set permissions back to what the user wanted
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if origMode != mode {
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err = os.Chmod(cPath, os.FileMode(origMode))
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if err != nil {
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toggledlog.Warn.Printf("Mkdir: Chmod failed: %v", err)
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}
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}
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return fuse.OK
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}
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func (fs *FS) Rmdir(path string, context *fuse.Context) (code fuse.Status) {
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cPath, err := fs.getBackingPath(path)
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if err != nil {
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return fuse.ToStatus(err)
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}
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if !fs.args.DirIV {
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return fuse.ToStatus(syscall.Rmdir(cPath))
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}
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parentDir := filepath.Dir(cPath)
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parentDirFd, err := os.Open(parentDir)
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if err != nil {
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return fuse.ToStatus(err)
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}
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defer parentDirFd.Close()
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cName := filepath.Base(cPath)
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dirfdRaw, err := syscall.Openat(int(parentDirFd.Fd()), cName,
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syscall.O_RDONLY, 0)
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if err == syscall.EACCES {
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// We need permission to read and modify the directory
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toggledlog.Debug.Printf("Rmdir: handling EACCESS")
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// TODO use syscall.Fstatat once it is available in Go
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var fi os.FileInfo
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fi, err = os.Lstat(cPath)
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if err != nil {
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toggledlog.Debug.Printf("Rmdir: Stat: %v", err)
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return fuse.ToStatus(err)
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}
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origMode := fi.Mode()
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// TODO use syscall.Chmodat once it is available in Go
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err = os.Chmod(cPath, origMode|0700)
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if err != nil {
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toggledlog.Debug.Printf("Rmdir: Chmod failed: %v", err)
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return fuse.ToStatus(err)
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}
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// Retry open
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var st syscall.Stat_t
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syscall.Lstat(cPath, &st)
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dirfdRaw, err = syscall.Openat(int(parentDirFd.Fd()), cName,
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syscall.O_RDONLY, 0)
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// Undo the chmod if removing the directory failed
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defer func() {
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if code != fuse.OK {
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err := os.Chmod(cPath, origMode)
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if err != nil {
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toggledlog.Warn.Printf("Rmdir: Chmod rollback failed: %v", err)
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}
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}
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}()
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}
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if err != nil {
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toggledlog.Debug.Printf("Rmdir: Open: %v", err)
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return fuse.ToStatus(err)
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}
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dirfd := os.NewFile(uintptr(dirfdRaw), cName)
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defer dirfd.Close()
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children, err := dirfd.Readdirnames(10)
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if err != nil {
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toggledlog.Warn.Printf("Rmdir: Readdirnames: %v", err)
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return fuse.ToStatus(err)
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}
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// If the directory is not empty besides gocryptfs.diriv, do not even
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// attempt the dance around gocryptfs.diriv.
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if len(children) > 1 {
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return fuse.ToStatus(syscall.ENOTEMPTY)
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}
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// Move "gocryptfs.diriv" to the parent dir as "gocryptfs.diriv.rmdir.XYZ"
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tmpName := fmt.Sprintf("gocryptfs.diriv.rmdir.%d", cryptocore.RandUint64())
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toggledlog.Debug.Printf("Rmdir: Renaming %s to %s", nametransform.DirIVFilename, tmpName)
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// The directory is in an inconsistent state between rename and rmdir.
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// Protect against concurrent readers.
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fs.dirIVLock.Lock()
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defer fs.dirIVLock.Unlock()
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err = syscall.Renameat(int(dirfd.Fd()), nametransform.DirIVFilename,
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int(parentDirFd.Fd()), tmpName)
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if err != nil {
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toggledlog.Warn.Printf("Rmdir: Renaming %s to %s failed: %v",
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nametransform.DirIVFilename, tmpName, err)
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return fuse.ToStatus(err)
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}
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// Actual Rmdir
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// TODO Use syscall.Unlinkat with the AT_REMOVEDIR flag once it is available
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// in Go
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err = syscall.Rmdir(cPath)
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if err != nil {
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// This can happen if another file in the directory was created in the
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// meantime, undo the rename
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err2 := syscall.Renameat(int(parentDirFd.Fd()), tmpName,
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int(dirfd.Fd()), nametransform.DirIVFilename)
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if err != nil {
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toggledlog.Warn.Printf("Rmdir: Rename rollback failed: %v", err2)
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}
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return fuse.ToStatus(err)
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}
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// Delete "gocryptfs.diriv.rmdir.INODENUMBER"
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err = syscall.Unlinkat(int(parentDirFd.Fd()), tmpName)
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if err != nil {
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toggledlog.Warn.Printf("Rmdir: Could not clean up %s: %v", tmpName, err)
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}
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// Delete .name file
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if nametransform.IsLongContent(cName) {
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nametransform.DeleteLongName(parentDirFd, cName)
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}
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// The now-deleted directory may have been in the DirIV cache. Clear it.
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fs.nameTransform.DirIVCache.Clear()
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return fuse.OK
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}
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func (fs *FS) OpenDir(dirName string, context *fuse.Context) ([]fuse.DirEntry, fuse.Status) {
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toggledlog.Debug.Printf("OpenDir(%s)", dirName)
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cDirName, err := fs.encryptPath(dirName)
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if err != nil {
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return nil, fuse.ToStatus(err)
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}
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// Read ciphertext directory
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cipherEntries, status := fs.FileSystem.OpenDir(cDirName, context)
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if cipherEntries == nil {
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return nil, status
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}
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// Get DirIV (stays nil if DirIV if off)
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var cachedIV []byte
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var cDirAbsPath string
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if fs.args.DirIV {
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// Read the DirIV once and use it for all later name decryptions
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cDirAbsPath = filepath.Join(fs.args.Cipherdir, cDirName)
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cachedIV, err = nametransform.ReadDirIV(cDirAbsPath)
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if err != nil {
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return nil, fuse.ToStatus(err)
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}
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}
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// Decrypted directory entries
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var plain []fuse.DirEntry
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var errorCount int
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// Filter and decrypt filenames
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for i := range cipherEntries {
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cName := cipherEntries[i].Name
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if dirName == "" && cName == configfile.ConfDefaultName {
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// silently ignore "gocryptfs.conf" in the top level dir
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continue
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}
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if fs.args.DirIV && cName == nametransform.DirIVFilename {
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// silently ignore "gocryptfs.diriv" everywhere if dirIV is enabled
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continue
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}
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if fs.args.PlaintextNames {
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plain = append(plain, cipherEntries[i])
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continue
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}
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// Handle long file name
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isLong := nametransform.LongNameNone
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if fs.args.LongNames {
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isLong = nametransform.NameType(cName)
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}
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if isLong == nametransform.LongNameContent {
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cNameLong, err := nametransform.ReadLongName(filepath.Join(cDirAbsPath, cName))
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if err != nil {
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toggledlog.Warn.Printf("Skipping file %q in dir %q: Could not read .name: %v",
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cName, cDirName, err)
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errorCount++
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continue
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}
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cName = cNameLong
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} else if isLong == nametransform.LongNameFilename {
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// ignore "gocryptfs.longname.*.name"
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continue
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}
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name, err := fs.nameTransform.DecryptName(cName, cachedIV)
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if err != nil {
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toggledlog.Warn.Printf("Skipping invalid name %q in dir %q: %s",
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cName, cDirName, err)
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errorCount++
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continue
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}
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cipherEntries[i].Name = name
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plain = append(plain, cipherEntries[i])
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}
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if errorCount > 0 && len(plain) == 0 {
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// Don't let the user stare on an empty directory. Report that things went
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// wrong.
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toggledlog.Warn.Printf("All %d entries in directory %q were invalid, returning EIO",
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errorCount, cDirName)
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status = fuse.EIO
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}
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return plain, status
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}
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