restic/internal/backend/local/local.go

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package local
import (
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"context"
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"io"
"os"
"path/filepath"
"syscall"
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"github.com/restic/restic/internal/errors"
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"github.com/restic/restic/internal/restic"
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"github.com/restic/restic/internal/backend"
"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/fs"
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)
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// Local is a backend in a local directory.
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type Local struct {
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Config
backend.Layout
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}
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// ensure statically that *Local implements restic.Backend.
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var _ restic.Backend = &Local{}
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const defaultLayout = "default"
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// Open opens the local backend as specified by config.
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func Open(cfg Config) (*Local, error) {
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debug.Log("open local backend at %v (layout %q)", cfg.Path, cfg.Layout)
l, err := backend.ParseLayout(&backend.LocalFilesystem{}, cfg.Layout, defaultLayout, cfg.Path)
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if err != nil {
return nil, err
}
return &Local{Config: cfg, Layout: l}, nil
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}
// Create creates all the necessary files and directories for a new local
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// backend at dir. Afterwards a new config blob should be created.
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func Create(cfg Config) (*Local, error) {
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debug.Log("create local backend at %v (layout %q)", cfg.Path, cfg.Layout)
l, err := backend.ParseLayout(&backend.LocalFilesystem{}, cfg.Layout, defaultLayout, cfg.Path)
if err != nil {
return nil, err
}
be := &Local{
Config: cfg,
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Layout: l,
}
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// test if config file already exists
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_, err = fs.Lstat(be.Filename(restic.Handle{Type: restic.ConfigFile}))
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if err == nil {
return nil, errors.New("config file already exists")
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}
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// create paths for data and refs
for _, d := range be.Paths() {
err := fs.MkdirAll(d, backend.Modes.Dir)
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if err != nil {
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return nil, errors.Wrap(err, "MkdirAll")
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}
}
return be, nil
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}
// Location returns this backend's location (the directory name).
func (b *Local) Location() string {
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return b.Path
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}
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// IsNotExist returns true if the error is caused by a non existing file.
func (b *Local) IsNotExist(err error) bool {
return os.IsNotExist(errors.Cause(err))
}
// Save stores data in the backend at the handle.
func (b *Local) Save(ctx context.Context, h restic.Handle, rd restic.RewindReader) error {
debug.Log("Save %v", h)
if err := h.Valid(); err != nil {
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return err
}
filename := b.Filename(h)
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// create new file
f, err := fs.OpenFile(filename, os.O_CREATE|os.O_EXCL|os.O_WRONLY, backend.Modes.File)
if b.IsNotExist(err) {
debug.Log("error %v: creating dir", err)
// error is caused by a missing directory, try to create it
mkdirErr := os.MkdirAll(filepath.Dir(filename), backend.Modes.Dir)
if mkdirErr != nil {
debug.Log("error creating dir %v: %v", filepath.Dir(filename), mkdirErr)
} else {
// try again
f, err = fs.OpenFile(filename, os.O_CREATE|os.O_EXCL|os.O_WRONLY, backend.Modes.File)
}
}
if err != nil {
return errors.Wrap(err, "OpenFile")
}
// save data, then sync
_, err = io.Copy(f, rd)
if err != nil {
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_ = f.Close()
return errors.Wrap(err, "Write")
}
if err = f.Sync(); err != nil {
pathErr, ok := err.(*os.PathError)
isNotSupported := ok && pathErr.Op == "sync" && pathErr.Err == syscall.ENOTSUP
// ignore error if filesystem does not support the sync operation
if !isNotSupported {
_ = f.Close()
return errors.Wrap(err, "Sync")
}
}
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err = f.Close()
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if err != nil {
return errors.Wrap(err, "Close")
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}
return setNewFileMode(filename, backend.Modes.File)
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}
// 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) {
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debug.Log("Load %v, length %v, offset %v", h, length, offset)
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if err := h.Valid(); err != nil {
return nil, err
}
if offset < 0 {
return nil, errors.New("offset is negative")
}
f, err := fs.Open(b.Filename(h))
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if err != nil {
return nil, err
}
if offset > 0 {
_, err = f.Seek(offset, 0)
if err != nil {
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_ = f.Close()
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return nil, err
}
}
if length > 0 {
return backend.LimitReadCloser(f, int64(length)), nil
}
return f, nil
}
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// Stat returns information about a blob.
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func (b *Local) Stat(ctx context.Context, h restic.Handle) (restic.FileInfo, error) {
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debug.Log("Stat %v", h)
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if err := h.Valid(); err != nil {
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return restic.FileInfo{}, err
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}
fi, err := fs.Stat(b.Filename(h))
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if err != nil {
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return restic.FileInfo{}, errors.Wrap(err, "Stat")
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}
return restic.FileInfo{Size: fi.Size(), Name: h.Name}, nil
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}
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// Test returns true if a blob of the given type and name exists in the backend.
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func (b *Local) Test(ctx context.Context, h restic.Handle) (bool, error) {
debug.Log("Test %v", h)
_, err := fs.Stat(b.Filename(h))
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if err != nil {
if os.IsNotExist(errors.Cause(err)) {
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return false, nil
}
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return false, errors.Wrap(err, "Stat")
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}
return true, nil
}
// Remove removes the blob with the given name and type.
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func (b *Local) Remove(ctx context.Context, h restic.Handle) error {
debug.Log("Remove %v", h)
fn := b.Filename(h)
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// reset read-only flag
err := fs.Chmod(fn, 0666)
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if err != nil {
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return errors.Wrap(err, "Chmod")
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}
return fs.Remove(fn)
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}
func isFile(fi os.FileInfo) bool {
return fi.Mode()&(os.ModeType|os.ModeCharDevice) == 0
}
// 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) error {
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debug.Log("List %v", t)
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basedir, subdirs := b.Basedir(t)
err := fs.Walk(basedir, func(path string, fi os.FileInfo, err error) error {
debug.Log("walk on %v\n", path)
if err != nil {
return err
}
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if path == basedir {
return nil
}
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if !isFile(fi) {
return nil
}
if fi.IsDir() && !subdirs {
return filepath.SkipDir
}
debug.Log("send %v\n", filepath.Base(path))
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rfi := restic.FileInfo{
Name: filepath.Base(path),
Size: fi.Size(),
}
if ctx.Err() != nil {
return ctx.Err()
}
err = fn(rfi)
if err != nil {
return err
}
return ctx.Err()
})
if b.IsNotExist(err) {
debug.Log("ignoring non-existing directory")
return nil
}
return err
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}
// Delete removes the repository and all files.
func (b *Local) Delete(ctx context.Context) error {
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debug.Log("Delete()")
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return fs.RemoveAll(b.Path)
}
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// Close closes all open files.
func (b *Local) Close() error {
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debug.Log("Close()")
// this does not need to do anything, all open files are closed within the
// same function.
return nil
}