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Rmdir: handle creating and removing unreadable directories
This patch also splits off Mkdir and Rmdir into its own file. Fixes issue #8, thanks to @diseq for the bug report.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,151 @@ | ||
| package pathfs_frontend | ||
|
|
||
| import ( | ||
| "os" | ||
| "path/filepath" | ||
| "syscall" | ||
| "fmt" | ||
|
|
||
| "github.com/hanwen/go-fuse/fuse" | ||
| "github.com/rfjakob/gocryptfs/cryptfs" | ||
| ) | ||
|
|
||
| func (fs *FS) Mkdir(relPath string, mode uint32, context *fuse.Context) (code fuse.Status) { | ||
| if fs.isFiltered(relPath) { | ||
| return fuse.EPERM | ||
| } | ||
| encPath, err := fs.getBackingPath(relPath) | ||
| if err != nil { | ||
| return fuse.ToStatus(err) | ||
| } | ||
| if !fs.args.DirIV { | ||
| return fuse.ToStatus(os.Mkdir(encPath, os.FileMode(mode))) | ||
| } | ||
|
|
||
| // We need write and execute permissions to create gocryptfs.diriv | ||
| origMode := mode | ||
| mode = mode | 0300 | ||
|
|
||
| // The new directory may take the place of an older one that is still in the cache | ||
| fs.CryptFS.DirIVCacheEnc.Clear() | ||
| // Create directory | ||
| fs.dirIVLock.Lock() | ||
| defer fs.dirIVLock.Unlock() | ||
| err = os.Mkdir(encPath, os.FileMode(mode)) | ||
| if err != nil { | ||
| return fuse.ToStatus(err) | ||
| } | ||
| // Create gocryptfs.diriv inside | ||
| err = cryptfs.WriteDirIV(encPath) | ||
| if err != nil { | ||
| // This should not happen | ||
| cryptfs.Warn.Printf("Mkdir: WriteDirIV failed: %v\n", err) | ||
| err2 := syscall.Rmdir(encPath) | ||
| if err2 != nil { | ||
| cryptfs.Warn.Printf("Mkdir: Rmdir rollback failed: %v\n", err2) | ||
| } | ||
| return fuse.ToStatus(err) | ||
| } | ||
|
|
||
| // Set permissions back to what the user wanted | ||
| if origMode != mode { | ||
| err = os.Chmod(encPath, os.FileMode(origMode)) | ||
| if err != nil { | ||
| cryptfs.Warn.Printf("Mkdir: Chmod failed: %v\n", err) | ||
| } | ||
| } | ||
|
|
||
| return fuse.OK | ||
| } | ||
|
|
||
| func (fs *FS) Rmdir(name string, context *fuse.Context) (code fuse.Status) { | ||
| encPath, err := fs.getBackingPath(name) | ||
| if err != nil { | ||
| return fuse.ToStatus(err) | ||
| } | ||
| if !fs.args.DirIV { | ||
| return fuse.ToStatus(syscall.Rmdir(encPath)) | ||
| } | ||
|
|
||
| // If the directory is not empty besides gocryptfs.diriv, do not even | ||
| // attempt the dance around gocryptfs.diriv. | ||
| fd, err := os.Open(encPath) | ||
| if perr, ok := err.(*os.PathError); ok && perr.Err == syscall.EACCES { | ||
| // We need permission to read and modify the directory | ||
| cryptfs.Debug.Printf("Rmdir: handling EACCESS\n") | ||
| fi, err2 := os.Stat(encPath) | ||
| if err2 != nil { | ||
| cryptfs.Debug.Printf("Rmdir: Stat: %v\n", err2) | ||
| return fuse.ToStatus(err2) | ||
| } | ||
| origMode := fi.Mode() | ||
| newMode := origMode | 0700 | ||
| err2 = os.Chmod(encPath, newMode) | ||
| if err2 != nil { | ||
| cryptfs.Debug.Printf("Rmdir: Chmod failed: %v\n", err2) | ||
| return fuse.ToStatus(err) | ||
| } | ||
| defer func () { | ||
| if code != fuse.OK { | ||
| // Undo the chmod if removing the directory failed | ||
| err3 := os.Chmod(encPath, origMode) | ||
| if err3 != nil { | ||
| cryptfs.Warn.Printf("Rmdir: Chmod rollback failed: %v\n", err2) | ||
| } | ||
| } | ||
| }() | ||
| // Retry open | ||
| fd, err = os.Open(encPath) | ||
| } | ||
| if err != nil { | ||
| cryptfs.Debug.Printf("Rmdir: Open: %v\n", err) | ||
| return fuse.ToStatus(err) | ||
| } | ||
| list, err := fd.Readdirnames(10) | ||
| fd.Close() | ||
| if err != nil { | ||
| cryptfs.Debug.Printf("Rmdir: Readdirnames: %v\n", err) | ||
| return fuse.ToStatus(err) | ||
| } | ||
| if len(list) > 1 { | ||
| return fuse.ToStatus(syscall.ENOTEMPTY) | ||
| } else if len(list) == 0 { | ||
| cryptfs.Warn.Printf("Rmdir: gocryptfs.diriv missing, allowing deletion\n") | ||
| return fuse.ToStatus(syscall.Rmdir(encPath)) | ||
| } | ||
|
|
||
| // Move "gocryptfs.diriv" to the parent dir as "gocryptfs.diriv.rmdir.XYZ" | ||
| dirivPath := filepath.Join(encPath, cryptfs.DIRIV_FILENAME) | ||
| parentDir := filepath.Dir(encPath) | ||
| tmpName := fmt.Sprintf("gocryptfs.diriv.rmdir.%d", cryptfs.RandUint64()) | ||
| tmpDirivPath := filepath.Join(parentDir, tmpName) | ||
| cryptfs.Debug.Printf("Rmdir: Renaming %s to %s\n", cryptfs.DIRIV_FILENAME, tmpDirivPath) | ||
| // The directory is in an inconsistent state between rename and rmdir. Protect against | ||
| // concurrent readers. | ||
| fs.dirIVLock.Lock() | ||
| defer fs.dirIVLock.Unlock() | ||
| err = os.Rename(dirivPath, tmpDirivPath) | ||
| if err != nil { | ||
| cryptfs.Warn.Printf("Rmdir: Renaming %s to %s failed: %v\n", cryptfs.DIRIV_FILENAME, tmpDirivPath, err) | ||
| return fuse.ToStatus(err) | ||
| } | ||
| // Actual Rmdir | ||
| err = syscall.Rmdir(encPath) | ||
| if err != nil { | ||
| // This can happen if another file in the directory was created in the | ||
| // meantime, undo the rename | ||
| err2 := os.Rename(tmpDirivPath, dirivPath) | ||
| if err2 != nil { | ||
| cryptfs.Warn.Printf("Rmdir: Rename rollback failed: %v\n", err2) | ||
| } | ||
| return fuse.ToStatus(err) | ||
| } | ||
| // Delete "gocryptfs.diriv.rmdir.INODENUMBER" | ||
| err = syscall.Unlink(tmpDirivPath) | ||
| if err != nil { | ||
| cryptfs.Warn.Printf("Rmdir: Could not clean up %s: %v\n", tmpName, err) | ||
| } | ||
| // The now-deleted directory may have been in the DirIV cache. Clear it. | ||
| fs.CryptFS.DirIVCacheEnc.Clear() | ||
| return fuse.OK | ||
| } |