restic/tree.go

402 lines
8.9 KiB
Go

package restic
import (
"encoding/json"
"errors"
"fmt"
"os"
"os/user"
"sort"
"strconv"
"strings"
"syscall"
"time"
"github.com/juju/arrar"
"github.com/restic/restic/backend"
)
type Tree []*Node
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"`
Tree *Tree `json:"-"`
path string
}
var (
ErrNodeNotFound = errors.New("named node not found")
ErrNodeAlreadyInTree = errors.New("node already present")
)
type Blob struct {
ID backend.ID `json:"id,omitempty"`
Size uint64 `json:"size,omitempty"`
Storage backend.ID `json:"sid,omitempty"` // encrypted ID
StorageSize uint64 `json:"ssize,omitempty"` // encrypted Size
}
type Blobs []Blob
func (n Node) String() string {
switch n.Type {
case "file":
return fmt.Sprintf("%s %5d %5d %6d %s %s",
n.Mode, n.UID, n.GID, n.Size, n.ModTime, n.Name)
case "dir":
return fmt.Sprintf("%s %5d %5d %6d %s %s",
n.Mode|os.ModeDir, n.UID, n.GID, n.Size, n.ModTime, n.Name)
}
return fmt.Sprintf("<Node(%s) %s>", n.Type, n.Name)
}
func (t Tree) String() string {
s := []string{}
for _, n := range t {
s = append(s, n.String())
}
return strings.Join(s, "\n")
}
func LoadTree(ch *ContentHandler, id backend.ID) (Tree, error) {
if id == nil {
return nil, nil
}
tree := Tree{}
err := ch.LoadJSON(backend.Tree, id, &tree)
if err != nil {
return nil, err
}
return tree, nil
}
// PopulateFrom copies subtrees and content from other when it hasn't changed.
func (t Tree) PopulateFrom(other Tree) error {
for _, node := range t {
// only copy entries for files
if node.Type != "file" {
continue
}
// find entry in other tree
oldNode, err := other.Find(node.Name)
// if the node could not be found, proceed to the next
if err == ErrNodeNotFound {
continue
}
// compare content
if node.SameContent(oldNode) {
// copy Content
node.Content = oldNode.Content
}
}
return nil
}
func (t *Tree) Insert(node *Node) error {
pos, _, err := t.find(node.Name)
if err == nil {
// already present
return ErrNodeAlreadyInTree
}
// insert blob
// https://code.google.com/p/go-wiki/wiki/bliceTricks
*t = append(*t, &Node{})
copy((*t)[pos+1:], (*t)[pos:])
(*t)[pos] = node
return nil
}
func (t Tree) find(name string) (int, *Node, error) {
pos := sort.Search(len(t), func(i int) bool {
return t[i].Name >= name
})
if pos < len(t) && t[pos].Name == name {
return pos, t[pos], nil
}
return pos, nil, ErrNodeNotFound
}
func (t Tree) Find(name string) (*Node, error) {
_, node, err := t.find(name)
return node, err
}
func (node *Node) fill_extra(path string, fi os.FileInfo) (err error) {
stat, ok := fi.Sys().(*syscall.Stat_t)
if !ok {
return
}
node.ChangeTime = time.Unix(stat.Ctim.Unix())
node.AccessTime = time.Unix(stat.Atim.Unix())
node.UID = stat.Uid
node.GID = stat.Gid
if u, nil := user.LookupId(strconv.Itoa(int(stat.Uid))); err == nil {
node.User = u.Username
}
// TODO: implement getgrnam() or use https://github.com/kless/osutil
// if g, nil := user.LookupId(strconv.Itoa(int(stat.Uid))); err == nil {
// node.User = u.Username
// }
node.Inode = stat.Ino
switch node.Type {
case "file":
node.Size = uint64(stat.Size)
node.Links = stat.Nlink
case "dir":
// nothing to do
case "symlink":
node.LinkTarget, err = os.Readlink(path)
case "dev":
node.Device = stat.Rdev
case "chardev":
node.Device = stat.Rdev
case "fifo":
// nothing to do
case "socket":
// nothing to do
default:
panic(fmt.Sprintf("invalid node type %q", node.Type))
}
return err
}
func NodeFromFileInfo(path string, fi os.FileInfo) (*Node, error) {
node := GetNode()
node.path = path
node.Name = fi.Name()
node.Mode = fi.Mode() & os.ModePerm
node.ModTime = fi.ModTime()
switch fi.Mode() & (os.ModeType | os.ModeCharDevice) {
case 0:
node.Type = "file"
case os.ModeDir:
node.Type = "dir"
case os.ModeSymlink:
node.Type = "symlink"
case os.ModeDevice | os.ModeCharDevice:
node.Type = "chardev"
case os.ModeDevice:
node.Type = "dev"
case os.ModeNamedPipe:
node.Type = "fifo"
case os.ModeSocket:
node.Type = "socket"
}
err := node.fill_extra(path, fi)
return node, err
}
func (node *Node) CreateAt(ch *ContentHandler, path string) error {
switch node.Type {
case "dir":
err := os.Mkdir(path, node.Mode)
if err != nil {
return arrar.Annotate(err, "Mkdir")
}
err = os.Lchown(path, int(node.UID), int(node.GID))
if err != nil {
return arrar.Annotate(err, "Lchown")
}
var utimes = []syscall.Timespec{
syscall.NsecToTimespec(node.AccessTime.UnixNano()),
syscall.NsecToTimespec(node.ModTime.UnixNano()),
}
err = syscall.UtimesNano(path, utimes)
if err != nil {
return arrar.Annotate(err, "Utimesnano")
}
case "file":
// TODO: handle hard links
f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY, 0600)
defer f.Close()
if err != nil {
return arrar.Annotate(err, "OpenFile")
}
for _, blobid := range node.Content {
buf, err := ch.Load(backend.Data, blobid)
if err != nil {
return arrar.Annotate(err, "Load")
}
_, err = f.Write(buf)
if err != nil {
return arrar.Annotate(err, "Write")
}
}
f.Close()
err = os.Lchown(path, int(node.UID), int(node.GID))
if err != nil {
return arrar.Annotate(err, "Lchown")
}
var utimes = []syscall.Timespec{
syscall.NsecToTimespec(node.AccessTime.UnixNano()),
syscall.NsecToTimespec(node.ModTime.UnixNano()),
}
err = syscall.UtimesNano(path, utimes)
if err != nil {
return arrar.Annotate(err, "Utimesnano")
}
case "symlink":
err := os.Symlink(node.LinkTarget, path)
if err != nil {
return arrar.Annotate(err, "Symlink")
}
err = os.Lchown(path, int(node.UID), int(node.GID))
if err != nil {
return arrar.Annotate(err, "Lchown")
}
f, err := os.OpenFile(path, O_PATH|syscall.O_NOFOLLOW, 0600)
defer f.Close()
if err != nil {
return arrar.Annotate(err, "OpenFile")
}
// TODO: Get Futimes() working on older Linux kernels (fails with 3.2.0)
// var utimes = []syscall.Timeval{
// syscall.NsecToTimeval(node.AccessTime.UnixNano()),
// syscall.NsecToTimeval(node.ModTime.UnixNano()),
// }
// err = syscall.Futimes(int(f.Fd()), utimes)
// if err != nil {
// return arrar.Annotate(err, "Futimes")
// }
return nil
case "dev":
err := syscall.Mknod(path, syscall.S_IFBLK|0600, int(node.Device))
if err != nil {
return arrar.Annotate(err, "Mknod")
}
case "chardev":
err := syscall.Mknod(path, syscall.S_IFCHR|0600, int(node.Device))
if err != nil {
return arrar.Annotate(err, "Mknod")
}
case "fifo":
err := syscall.Mkfifo(path, 0600)
if err != nil {
return arrar.Annotate(err, "Mkfifo")
}
case "socket":
// nothing to do, we do not restore sockets
default:
return fmt.Errorf("filetype %q not implemented!\n", node.Type)
}
err := os.Chmod(path, node.Mode)
if err != nil {
return arrar.Annotate(err, "Chmod")
}
err = os.Chown(path, int(node.UID), int(node.GID))
if err != nil {
return arrar.Annotate(err, "Chown")
}
err = os.Chtimes(path, node.AccessTime, node.ModTime)
if err != nil {
return arrar.Annotate(err, "Chtimes")
}
return nil
}
func (node Node) SameContent(olderNode *Node) bool {
// if this node has a type other than "file", treat as if content has changed
if node.Type != "file" {
return false
}
// if the name or type has changed, this is surely something different
if node.Name != olderNode.Name || node.Type != olderNode.Type {
return false
}
// if timestamps or inodes differ, content has changed
if node.ModTime != olderNode.ModTime ||
node.ChangeTime != olderNode.ChangeTime ||
node.Inode != olderNode.Inode {
return false
}
// otherwise the node is assumed to have the same content
return true
}
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
var nj *nodeJSON = (*nodeJSON)(node)
err := json.Unmarshal(data, nj)
if err != nil {
return err
}
nj.Name, err = strconv.Unquote(`"` + nj.Name + `"`)
return err
}
func (b Blob) Free() {
if b.ID != nil {
b.ID.Free()
}
if b.Storage != nil {
b.Storage.Free()
}
}