diff options
| -rw-r--r-- | pathfs_frontend/fs.go | 62 |
1 files changed, 59 insertions, 3 deletions
diff --git a/pathfs_frontend/fs.go b/pathfs_frontend/fs.go index 3d6d79c..9c809df 100644 --- a/pathfs_frontend/fs.go +++ b/pathfs_frontend/fs.go @@ -1,6 +1,8 @@ package pathfs_frontend import ( + "fmt" + "sync" "syscall" "io/ioutil" "os" @@ -17,6 +19,7 @@ type FS struct { *cryptfs.CryptFS pathfs.FileSystem // loopbackFileSystem, see go-fuse/fuse/pathfs/loopback.go backing string // Backing directory + dirivLock sync.RWMutex // Global lock that is taken if any "gocryptfs.diriv" file is modified } // Encrypted FUSE overlay filesystem @@ -182,10 +185,11 @@ func (fs *FS) Mkdir(relPath string, mode uint32, context *fuse.Context) (code fu // 0444 permissions: the file is not secret but should not be written to err = ioutil.WriteFile(dirivPath, diriv, 0444) if err != nil { + // This should not happen cryptfs.Warn.Printf("Creating %s in dir %s failed: %v\n", cryptfs.DIRIV_FILENAME, encPath, err) err2 := syscall.Rmdir(encPath) if err2 != nil { - cryptfs.Warn.Printf("Removing broken directory failed: %v\n", err2) + cryptfs.Warn.Printf("Mkdir: Rollback failed: %v\n", err2) } return fuse.ToStatus(err) } @@ -199,13 +203,65 @@ func (fs *FS) Unlink(name string, context *fuse.Context) (code fuse.Status) { cName := fs.EncryptPath(name) code = fs.FileSystem.Unlink(cName, context) if code != fuse.OK { - cryptfs.Warn.Printf("Unlink failed on %s [%s], code=%s\n", name, cName, code.String()) + cryptfs.Debug.Printf("Unlink failed on %s [%s], code=%s\n", name, cName, code.String()) } return code } func (fs *FS) Rmdir(name string, context *fuse.Context) (code fuse.Status) { - return fs.FileSystem.Rmdir(fs.EncryptPath(name), context) + encPath := fs.GetPath(name) + + // If the directory is not empty besides gocryptfs.diriv, do not even + // attempt the dance around gocryptfs.diriv. + fd, err := os.Open(encPath) + if err != nil { + return fuse.ToStatus(err) + } + defer fd.Close() + list, err := fd.Readdirnames(10) + if err != nil { + return fuse.ToStatus(err) + } + if len(list) > 1 { + return fuse.ToStatus(syscall.ENOTEMPTY) + } + + // Move "gocryptfs.diriv" to the parent dir under name "gocryptfs.diriv.rmdir.INODENUMBER" + var st syscall.Stat_t + err = syscall.Fstat(int(fd.Fd()), &st) + if err != nil { + return fuse.ToStatus(err) + } + dirivPath := filepath.Join(encPath, cryptfs.DIRIV_FILENAME) + parentDir := filepath.Dir(encPath) + tmpName := fmt.Sprintf("gocryptfs.diriv.rmdir.%d", st.Ino) + tmpDirivPath := filepath.Join(parentDir, tmpName) + cryptfs.Debug.Printf("Rmdir: Renaming %s to %s\n", cryptfs.DIRIV_FILENAME, tmpDirivPath) + fs.dirivLock.Lock() // directory will be in an inconsistent state after the rename + 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: 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) + } + + return fuse.OK } func (fs *FS) Symlink(pointedTo string, linkName string, context *fuse.Context) (code fuse.Status) { |