restic/node.go

428 lines
9.0 KiB
Go

package restic
import (
"encoding/json"
"fmt"
"os"
"os/user"
"strconv"
"sync"
"syscall"
"time"
"github.com/juju/errors"
"github.com/restic/restic/backend"
"github.com/restic/restic/debug"
"github.com/restic/restic/pack"
"github.com/restic/restic/repository"
)
// Node is a file, directory or other item in a backup.
type Node struct {
Name string `json:"name"`
Type string `json:"type"`
Mode os.FileMode `json:"mode,omitempty"`
ModTime time.Time `json:"mtime,omitempty"`
AccessTime time.Time `json:"atime,omitempty"`
ChangeTime time.Time `json:"ctime,omitempty"`
UID uint32 `json:"uid"`
GID uint32 `json:"gid"`
User string `json:"user,omitempty"`
Group string `json:"group,omitempty"`
Inode uint64 `json:"inode,omitempty"`
Size uint64 `json:"size,omitempty"`
Links uint64 `json:"links,omitempty"`
LinkTarget string `json:"linktarget,omitempty"`
Device uint64 `json:"device,omitempty"`
Content []backend.ID `json:"content"`
Subtree backend.ID `json:"subtree,omitempty"`
Error string `json:"error,omitempty"`
tree *Tree
path string
err error
blobs repository.Blobs
}
func (node Node) String() string {
switch node.Type {
case "file":
return fmt.Sprintf("%s %5d %5d %6d %s %s",
node.Mode, node.UID, node.GID, node.Size, node.ModTime, node.Name)
case "dir":
return fmt.Sprintf("%s %5d %5d %6d %s %s",
node.Mode|os.ModeDir, node.UID, node.GID, node.Size, node.ModTime, node.Name)
}
return fmt.Sprintf("<Node(%s) %s>", node.Type, node.Name)
}
func (node Node) Tree() *Tree {
return node.tree
}
// NodeFromFileInfo returns a new node from the given path and FileInfo.
func NodeFromFileInfo(path string, fi os.FileInfo) (*Node, error) {
node := &Node{
path: path,
Name: fi.Name(),
Mode: fi.Mode() & (os.ModePerm | os.ModeType),
ModTime: fi.ModTime(),
}
node.Type = nodeTypeFromFileInfo(fi)
if node.Type == "file" {
node.Size = uint64(fi.Size())
}
err := node.fillExtra(path, fi)
return node, err
}
func nodeTypeFromFileInfo(fi os.FileInfo) string {
switch fi.Mode() & (os.ModeType | os.ModeCharDevice) {
case 0:
return "file"
case os.ModeDir:
return "dir"
case os.ModeSymlink:
return "symlink"
case os.ModeDevice | os.ModeCharDevice:
return "chardev"
case os.ModeDevice:
return "dev"
case os.ModeNamedPipe:
return "fifo"
case os.ModeSocket:
return "socket"
}
return ""
}
// CreateAt creates the node at the given path and restores all the meta data.
func (node *Node) CreateAt(path string, repo *repository.Repo) error {
switch node.Type {
case "dir":
if err := node.createDirAt(path); err != nil {
return errors.Annotate(err, "createDirAt")
}
case "file":
if err := node.createFileAt(path, repo); err != nil {
return errors.Annotate(err, "createFileAt")
}
case "symlink":
if err := node.createSymlinkAt(path); err != nil {
return errors.Annotate(err, "createSymlinkAt")
}
case "dev":
if err := node.createDevAt(path); err != nil {
return errors.Annotate(err, "createDevAt")
}
case "chardev":
if err := node.createCharDevAt(path); err != nil {
return errors.Annotate(err, "createCharDevAt")
}
case "fifo":
if err := node.createFifoAt(path); err != nil {
return errors.Annotate(err, "createFifoAt")
}
case "socket":
return nil
default:
return fmt.Errorf("filetype %q not implemented!\n", node.Type)
}
return node.restoreMetadata(path)
}
func (node Node) restoreMetadata(path string) error {
var err error
err = os.Lchown(path, int(node.UID), int(node.GID))
if err != nil {
return errors.Annotate(err, "Lchown")
}
if node.Type == "symlink" {
return nil
}
err = os.Chmod(path, node.Mode)
if err != nil {
return errors.Annotate(err, "Chmod")
}
var utimes = []syscall.Timespec{
syscall.NsecToTimespec(node.AccessTime.UnixNano()),
syscall.NsecToTimespec(node.ModTime.UnixNano()),
}
err = syscall.UtimesNano(path, utimes)
if err != nil {
return errors.Annotate(err, "UtimesNano")
}
return nil
}
func (node Node) createDirAt(path string) error {
err := os.Mkdir(path, node.Mode)
if err != nil {
return errors.Annotate(err, "Mkdir")
}
return nil
}
func (node Node) createFileAt(path string, repo *repository.Repo) error {
f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY, 0600)
defer f.Close()
if err != nil {
return errors.Annotate(err, "OpenFile")
}
for _, id := range node.Content {
buf, err := repo.LoadBlob(pack.Data, id)
if err != nil {
return errors.Annotate(err, "Load")
}
_, err = f.Write(buf)
if err != nil {
return errors.Annotate(err, "Write")
}
}
return nil
}
func (node Node) createSymlinkAt(path string) error {
err := os.Symlink(node.LinkTarget, path)
if err != nil {
return errors.Annotate(err, "Symlink")
}
return nil
}
func (node *Node) createDevAt(path string) error {
return syscall.Mknod(path, syscall.S_IFBLK|0600, int(node.Device))
}
func (node *Node) createCharDevAt(path string) error {
return syscall.Mknod(path, syscall.S_IFCHR|0600, int(node.Device))
}
func (node *Node) createFifoAt(path string) error {
return syscall.Mkfifo(path, 0600)
}
func (node Node) MarshalJSON() ([]byte, error) {
type nodeJSON Node
nj := nodeJSON(node)
name := strconv.Quote(node.Name)
nj.Name = name[1 : len(name)-1]
return json.Marshal(nj)
}
func (node *Node) UnmarshalJSON(data []byte) error {
type nodeJSON Node
nj := (*nodeJSON)(node)
err := json.Unmarshal(data, nj)
if err != nil {
return err
}
nj.Name, err = strconv.Unquote(`"` + nj.Name + `"`)
return err
}
func (node Node) Equals(other Node) bool {
if node.Name != other.Name {
return false
}
if node.Type != other.Type {
return false
}
if node.Mode != other.Mode {
return false
}
if node.ModTime != other.ModTime {
return false
}
if node.AccessTime != other.AccessTime {
return false
}
if node.ChangeTime != other.ChangeTime {
return false
}
if node.UID != other.UID {
return false
}
if node.GID != other.GID {
return false
}
if node.User != other.User {
return false
}
if node.Group != other.Group {
return false
}
if node.Inode != other.Inode {
return false
}
if node.Size != other.Size {
return false
}
if node.Links != other.Links {
return false
}
if node.LinkTarget != other.LinkTarget {
return false
}
if node.Device != other.Device {
return false
}
if !node.sameContent(other) {
return false
}
if !node.Subtree.Equal(other.Subtree) {
return false
}
if node.Error != other.Error {
return false
}
return true
}
func (node Node) sameContent(other Node) bool {
if node.Content == nil {
return other.Content == nil
}
if other.Content == nil {
return false
}
if len(node.Content) != len(other.Content) {
return false
}
for i := 0; i < len(node.Content); i++ {
if !node.Content[i].Equal(other.Content[i]) {
return false
}
}
return true
}
func (node *Node) isNewer(path string, fi os.FileInfo) bool {
if node.Type != "file" {
debug.Log("node.isNewer", "node %v is newer: not file", path)
return true
}
tpe := nodeTypeFromFileInfo(fi)
if node.Name != fi.Name() || node.Type != tpe {
debug.Log("node.isNewer", "node %v is newer: name or type changed", path)
return true
}
extendedStat := fi.Sys().(*syscall.Stat_t)
inode := extendedStat.Ino
size := uint64(extendedStat.Size)
if node.ModTime != fi.ModTime() ||
node.ChangeTime != changeTime(extendedStat) ||
node.Inode != uint64(inode) ||
node.Size != size {
debug.Log("node.isNewer", "node %v is newer: timestamp, size or inode changed", path)
return true
}
debug.Log("node.isNewer", "node %v is not newer", path)
return false
}
func (node *Node) fillUser(stat *syscall.Stat_t) error {
node.UID = stat.Uid
node.GID = stat.Gid
username, err := lookupUsername(strconv.Itoa(int(stat.Uid)))
if err != nil {
return errors.Annotate(err, "fillUser")
}
node.User = username
return nil
}
var (
uidLookupCache = make(map[string]string)
uidLookupCacheMutex = sync.RWMutex{}
)
func lookupUsername(uid string) (string, error) {
uidLookupCacheMutex.RLock()
value, ok := uidLookupCache[uid]
uidLookupCacheMutex.RUnlock()
if ok {
return value, nil
}
u, err := user.LookupId(uid)
if err != nil {
return "", err
}
uidLookupCacheMutex.Lock()
uidLookupCache[uid] = u.Username
uidLookupCacheMutex.Unlock()
return u.Username, nil
}
func (node *Node) fillExtra(path string, fi os.FileInfo) error {
stat, ok := fi.Sys().(*syscall.Stat_t)
if !ok {
return nil
}
node.Inode = uint64(stat.Ino)
node.fillTimes(stat)
var err error
if err = node.fillUser(stat); err != nil {
return errors.Annotate(err, "fillExtra")
}
switch node.Type {
case "file":
node.Size = uint64(stat.Size)
node.Links = uint64(stat.Nlink)
case "dir":
case "symlink":
node.LinkTarget, err = os.Readlink(path)
case "dev":
node.Device = uint64(stat.Rdev)
case "chardev":
node.Device = uint64(stat.Rdev)
case "fifo":
case "socket":
default:
err = fmt.Errorf("invalid node type %q", node.Type)
}
return err
}