package local import ( "context" "hash" "io" "io/ioutil" "os" "path/filepath" "syscall" "github.com/restic/restic/internal/errors" "github.com/restic/restic/internal/restic" "github.com/restic/restic/internal/backend" "github.com/restic/restic/internal/debug" "github.com/restic/restic/internal/fs" "github.com/cenkalti/backoff/v4" ) // Local is a backend in a local directory. type Local struct { Config sem *backend.Semaphore backend.Layout backend.Modes } // ensure statically that *Local implements restic.Backend. var _ restic.Backend = &Local{} const defaultLayout = "default" func open(ctx context.Context, cfg Config) (*Local, error) { l, err := backend.ParseLayout(ctx, &backend.LocalFilesystem{}, cfg.Layout, defaultLayout, cfg.Path) if err != nil { return nil, err } sem, err := backend.NewSemaphore(cfg.Connections) if err != nil { return nil, err } fi, err := fs.Stat(l.Filename(restic.Handle{Type: restic.ConfigFile})) m := backend.DeriveModesFromFileInfo(fi, err) debug.Log("using (%03O file, %03O dir) permissions", m.File, m.Dir) return &Local{ Config: cfg, Layout: l, sem: sem, Modes: m, }, nil } // Open opens the local backend as specified by config. func Open(ctx context.Context, cfg Config) (*Local, error) { debug.Log("open local backend at %v (layout %q)", cfg.Path, cfg.Layout) return open(ctx, cfg) } // Create creates all the necessary files and directories for a new local // backend at dir. Afterwards a new config blob should be created. func Create(ctx context.Context, cfg Config) (*Local, error) { debug.Log("create local backend at %v (layout %q)", cfg.Path, cfg.Layout) be, err := open(ctx, cfg) if err != nil { return nil, err } // test if config file already exists _, err = fs.Lstat(be.Filename(restic.Handle{Type: restic.ConfigFile})) if err == nil { return nil, errors.New("config file already exists") } // create paths for data and refs for _, d := range be.Paths() { err := fs.MkdirAll(d, be.Modes.Dir) if err != nil { return nil, errors.WithStack(err) } } return be, nil } func (b *Local) Connections() uint { return b.Config.Connections } // Location returns this backend's location (the directory name). func (b *Local) Location() string { return b.Path } // Hasher may return a hash function for calculating a content hash for the backend func (b *Local) Hasher() hash.Hash { return nil } // HasAtomicReplace returns whether Save() can atomically replace files func (b *Local) HasAtomicReplace() bool { return true } // IsNotExist returns true if the error is caused by a non existing file. func (b *Local) IsNotExist(err error) bool { return errors.Is(err, os.ErrNotExist) } // Save stores data in the backend at the handle. func (b *Local) Save(ctx context.Context, h restic.Handle, rd restic.RewindReader) (err error) { debug.Log("Save %v", h) if err := h.Valid(); err != nil { return backoff.Permanent(err) } finalname := b.Filename(h) dir := filepath.Dir(finalname) defer func() { // Mark non-retriable errors as such if errors.Is(err, syscall.ENOSPC) || os.IsPermission(err) { err = backoff.Permanent(err) } }() b.sem.GetToken() defer b.sem.ReleaseToken() // Create new file with a temporary name. tmpname := filepath.Base(finalname) + "-tmp-" f, err := tempFile(dir, tmpname) if b.IsNotExist(err) { debug.Log("error %v: creating dir", err) // error is caused by a missing directory, try to create it mkdirErr := fs.MkdirAll(dir, b.Modes.Dir) if mkdirErr != nil { debug.Log("error creating dir %v: %v", dir, mkdirErr) } else { // try again f, err = tempFile(dir, tmpname) } } if err != nil { return errors.WithStack(err) } defer func(f *os.File) { if err != nil { _ = f.Close() // Double Close is harmless. // Remove after Rename is harmless: we embed the final name in the // temporary's name and no other goroutine will get the same data to // Save, so the temporary name should never be reused by another // goroutine. _ = fs.Remove(f.Name()) } }(f) // save data, then sync wbytes, err := io.Copy(f, rd) if err != nil { return errors.WithStack(err) } // sanity check if wbytes != rd.Length() { return errors.Errorf("wrote %d bytes instead of the expected %d bytes", wbytes, rd.Length()) } // Ignore error if filesystem does not support fsync. err = f.Sync() syncNotSup := errors.Is(err, syscall.ENOTSUP) if err != nil && !syncNotSup { return errors.WithStack(err) } // Close, then rename. Windows doesn't like the reverse order. if err = f.Close(); err != nil { return errors.WithStack(err) } if err = os.Rename(f.Name(), finalname); err != nil { return errors.WithStack(err) } // Now sync the directory to commit the Rename. if !syncNotSup { err = fsyncDir(dir) if err != nil { return errors.WithStack(err) } } // try to mark file as read-only to avoid accidential modifications // ignore if the operation fails as some filesystems don't allow the chmod call // e.g. exfat and network file systems with certain mount options err = setFileReadonly(finalname, b.Modes.File) if err != nil && !os.IsPermission(err) { return errors.WithStack(err) } return nil } var tempFile = ioutil.TempFile // Overridden by test. // Load runs fn with a reader that yields the contents of the file at h at the // given offset. func (b *Local) Load(ctx context.Context, h restic.Handle, length int, offset int64, fn func(rd io.Reader) error) error { return backend.DefaultLoad(ctx, h, length, offset, b.openReader, fn) } func (b *Local) openReader(ctx context.Context, h restic.Handle, length int, offset int64) (io.ReadCloser, error) { debug.Log("Load %v, length %v, offset %v", h, length, offset) if err := h.Valid(); err != nil { return nil, backoff.Permanent(err) } if offset < 0 { return nil, errors.New("offset is negative") } b.sem.GetToken() f, err := fs.Open(b.Filename(h)) if err != nil { b.sem.ReleaseToken() return nil, err } if offset > 0 { _, err = f.Seek(offset, 0) if err != nil { b.sem.ReleaseToken() _ = f.Close() return nil, err } } r := b.sem.ReleaseTokenOnClose(f, nil) if length > 0 { return backend.LimitReadCloser(r, int64(length)), nil } return r, nil } // Stat returns information about a blob. func (b *Local) Stat(ctx context.Context, h restic.Handle) (restic.FileInfo, error) { debug.Log("Stat %v", h) if err := h.Valid(); err != nil { return restic.FileInfo{}, backoff.Permanent(err) } b.sem.GetToken() defer b.sem.ReleaseToken() fi, err := fs.Stat(b.Filename(h)) if err != nil { return restic.FileInfo{}, errors.WithStack(err) } return restic.FileInfo{Size: fi.Size(), Name: h.Name}, nil } // Test returns true if a blob of the given type and name exists in the backend. func (b *Local) Test(ctx context.Context, h restic.Handle) (bool, error) { debug.Log("Test %v", h) b.sem.GetToken() defer b.sem.ReleaseToken() _, err := fs.Stat(b.Filename(h)) if err != nil { if b.IsNotExist(err) { return false, nil } return false, errors.WithStack(err) } return true, nil } // Remove removes the blob with the given name and type. func (b *Local) Remove(ctx context.Context, h restic.Handle) error { debug.Log("Remove %v", h) fn := b.Filename(h) b.sem.GetToken() defer b.sem.ReleaseToken() // reset read-only flag err := fs.Chmod(fn, 0666) if err != nil && !os.IsPermission(err) { return errors.WithStack(err) } return fs.Remove(fn) } // List runs fn for each file in the backend which has the type t. When an // error occurs (or fn returns an error), List stops and returns it. func (b *Local) List(ctx context.Context, t restic.FileType, fn func(restic.FileInfo) error) (err error) { debug.Log("List %v", t) basedir, subdirs := b.Basedir(t) if subdirs { err = visitDirs(ctx, basedir, fn) } else { err = visitFiles(ctx, basedir, fn, false) } if b.IsNotExist(err) { debug.Log("ignoring non-existing directory") return nil } return err } // The following two functions are like filepath.Walk, but visit only one or // two levels of directory structure (including dir itself as the first level). // Also, visitDirs assumes it sees a directory full of directories, while // visitFiles wants a directory full or regular files. func visitDirs(ctx context.Context, dir string, fn func(restic.FileInfo) error) error { d, err := fs.Open(dir) if err != nil { return err } sub, err := d.Readdirnames(-1) if err != nil { // ignore subsequent errors _ = d.Close() return err } err = d.Close() if err != nil { return err } for _, f := range sub { err = visitFiles(ctx, filepath.Join(dir, f), fn, true) if err != nil { return err } } return ctx.Err() } func visitFiles(ctx context.Context, dir string, fn func(restic.FileInfo) error, ignoreNotADirectory bool) error { d, err := fs.Open(dir) if err != nil { return err } if ignoreNotADirectory { fi, err := d.Stat() if err != nil || !fi.IsDir() { // ignore subsequent errors _ = d.Close() return err } } sub, err := d.Readdir(-1) if err != nil { // ignore subsequent errors _ = d.Close() return err } err = d.Close() if err != nil { return err } for _, fi := range sub { select { case <-ctx.Done(): return ctx.Err() default: } err := fn(restic.FileInfo{ Name: fi.Name(), Size: fi.Size(), }) if err != nil { return err } } return nil } // Delete removes the repository and all files. func (b *Local) Delete(ctx context.Context) error { debug.Log("Delete()") return fs.RemoveAll(b.Path) } // Close closes all open files. func (b *Local) Close() error { debug.Log("Close()") // this does not need to do anything, all open files are closed within the // same function. return nil }