mirror of
https://github.com/restic/restic.git
synced 2024-12-23 08:16:36 +00:00
734 lines
21 KiB
Go
734 lines
21 KiB
Go
package restorer
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import (
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"context"
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"fmt"
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"io"
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"os"
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"path/filepath"
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"sync/atomic"
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"github.com/restic/restic/internal/debug"
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"github.com/restic/restic/internal/errors"
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"github.com/restic/restic/internal/fs"
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"github.com/restic/restic/internal/restic"
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restoreui "github.com/restic/restic/internal/ui/restore"
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"golang.org/x/sync/errgroup"
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)
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// Restorer is used to restore a snapshot to a directory.
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type Restorer struct {
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repo restic.Repository
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sn *restic.Snapshot
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opts Options
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fileList map[string]bool
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Error func(location string, err error) error
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Warn func(message string)
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// SelectFilter determines whether the item is selectedForRestore or whether a childMayBeSelected.
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// selectedForRestore must not depend on isDir as `removeUnexpectedFiles` always passes false to isDir.
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SelectFilter func(item string, isDir bool) (selectedForRestore bool, childMayBeSelected bool)
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}
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var restorerAbortOnAllErrors = func(_ string, err error) error { return err }
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type Options struct {
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DryRun bool
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Sparse bool
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Progress *restoreui.Progress
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Overwrite OverwriteBehavior
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Delete bool
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}
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type OverwriteBehavior int
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// Constants for different overwrite behavior
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const (
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OverwriteAlways OverwriteBehavior = iota
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// OverwriteIfChanged is like OverwriteAlways except that it skips restoring the content
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// of files with matching size&mtime. Metadata is always restored.
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OverwriteIfChanged
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OverwriteIfNewer
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OverwriteNever
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OverwriteInvalid
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)
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// Set implements the method needed for pflag command flag parsing.
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func (c *OverwriteBehavior) Set(s string) error {
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switch s {
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case "always":
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*c = OverwriteAlways
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case "if-changed":
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*c = OverwriteIfChanged
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case "if-newer":
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*c = OverwriteIfNewer
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case "never":
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*c = OverwriteNever
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default:
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*c = OverwriteInvalid
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return fmt.Errorf("invalid overwrite behavior %q, must be one of (always|if-newer|never)", s)
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}
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return nil
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}
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func (c *OverwriteBehavior) String() string {
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switch *c {
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case OverwriteAlways:
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return "always"
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case OverwriteIfChanged:
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return "if-changed"
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case OverwriteIfNewer:
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return "if-newer"
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case OverwriteNever:
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return "never"
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default:
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return "invalid"
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}
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}
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func (c *OverwriteBehavior) Type() string {
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return "behavior"
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}
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// NewRestorer creates a restorer preloaded with the content from the snapshot id.
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func NewRestorer(repo restic.Repository, sn *restic.Snapshot, opts Options) *Restorer {
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r := &Restorer{
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repo: repo,
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opts: opts,
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fileList: make(map[string]bool),
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Error: restorerAbortOnAllErrors,
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SelectFilter: func(string, bool) (bool, bool) { return true, true },
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sn: sn,
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}
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return r
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}
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type treeVisitor struct {
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enterDir func(node *restic.Node, target, location string) error
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visitNode func(node *restic.Node, target, location string) error
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// 'entries' contains all files the snapshot contains for this node. This also includes files
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// ignored by the SelectFilter.
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leaveDir func(node *restic.Node, target, location string, entries []string) error
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}
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func (res *Restorer) sanitizeError(location string, err error) error {
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switch err {
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case nil, context.Canceled, context.DeadlineExceeded:
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// Context errors are permanent.
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return err
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default:
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return res.Error(location, err)
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}
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}
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// traverseTree traverses a tree from the repo and calls treeVisitor.
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// target is the path in the file system, location within the snapshot.
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func (res *Restorer) traverseTree(ctx context.Context, target string, treeID restic.ID, visitor treeVisitor) error {
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location := string(filepath.Separator)
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if visitor.enterDir != nil {
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err := res.sanitizeError(location, visitor.enterDir(nil, target, location))
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if err != nil {
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return err
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}
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}
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childFilenames, hasRestored, err := res.traverseTreeInner(ctx, target, location, treeID, visitor)
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if err != nil {
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return err
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}
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if hasRestored && visitor.leaveDir != nil {
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err = res.sanitizeError(location, visitor.leaveDir(nil, target, location, childFilenames))
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}
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return err
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}
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func (res *Restorer) traverseTreeInner(ctx context.Context, target, location string, treeID restic.ID, visitor treeVisitor) (filenames []string, hasRestored bool, err error) {
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debug.Log("%v %v %v", target, location, treeID)
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tree, err := restic.LoadTree(ctx, res.repo, treeID)
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if err != nil {
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debug.Log("error loading tree %v: %v", treeID, err)
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return nil, hasRestored, res.sanitizeError(location, err)
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}
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if res.opts.Delete {
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filenames = make([]string, 0, len(tree.Nodes))
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}
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for i, node := range tree.Nodes {
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if ctx.Err() != nil {
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return nil, hasRestored, ctx.Err()
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}
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// allow GC of tree node
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tree.Nodes[i] = nil
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if res.opts.Delete {
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// just track all files included in the tree node to simplify the control flow.
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// tracking too many files does not matter except for a slightly elevated memory usage
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filenames = append(filenames, node.Name)
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}
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// ensure that the node name does not contain anything that refers to a
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// top-level directory.
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nodeName := filepath.Base(filepath.Join(string(filepath.Separator), node.Name))
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if nodeName != node.Name {
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debug.Log("node %q has invalid name %q", node.Name, nodeName)
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err := res.sanitizeError(location, errors.Errorf("invalid child node name %s", node.Name))
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if err != nil {
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return nil, hasRestored, err
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}
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// force disable deletion to prevent unexpected behavior
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res.opts.Delete = false
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continue
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}
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nodeTarget := filepath.Join(target, nodeName)
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nodeLocation := filepath.Join(location, nodeName)
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if target == nodeTarget || !fs.HasPathPrefix(target, nodeTarget) {
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debug.Log("target: %v %v", target, nodeTarget)
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debug.Log("node %q has invalid target path %q", node.Name, nodeTarget)
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err := res.sanitizeError(nodeLocation, errors.New("node has invalid path"))
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if err != nil {
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return nil, hasRestored, err
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}
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// force disable deletion to prevent unexpected behavior
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res.opts.Delete = false
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continue
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}
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// sockets cannot be restored
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if node.Type == "socket" {
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continue
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}
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selectedForRestore, childMayBeSelected := res.SelectFilter(nodeLocation, node.Type == "dir")
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debug.Log("SelectFilter returned %v %v for %q", selectedForRestore, childMayBeSelected, nodeLocation)
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if selectedForRestore {
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hasRestored = true
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}
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if node.Type == "dir" {
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if node.Subtree == nil {
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return nil, hasRestored, errors.Errorf("Dir without subtree in tree %v", treeID.Str())
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}
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if selectedForRestore && visitor.enterDir != nil {
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err = res.sanitizeError(nodeLocation, visitor.enterDir(node, nodeTarget, nodeLocation))
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if err != nil {
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return nil, hasRestored, err
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}
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}
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// keep track of restored child status
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// so metadata of the current directory are restored on leaveDir
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childHasRestored := false
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var childFilenames []string
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if childMayBeSelected {
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childFilenames, childHasRestored, err = res.traverseTreeInner(ctx, nodeTarget, nodeLocation, *node.Subtree, visitor)
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err = res.sanitizeError(nodeLocation, err)
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if err != nil {
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return nil, hasRestored, err
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}
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// inform the parent directory to restore parent metadata on leaveDir if needed
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if childHasRestored {
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hasRestored = true
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}
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}
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// metadata need to be restore when leaving the directory in both cases
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// selected for restore or any child of any subtree have been restored
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if (selectedForRestore || childHasRestored) && visitor.leaveDir != nil {
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err = res.sanitizeError(nodeLocation, visitor.leaveDir(node, nodeTarget, nodeLocation, childFilenames))
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if err != nil {
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return nil, hasRestored, err
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}
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}
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continue
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}
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if selectedForRestore {
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err = res.sanitizeError(nodeLocation, visitor.visitNode(node, nodeTarget, nodeLocation))
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if err != nil {
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return nil, hasRestored, err
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}
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}
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}
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return filenames, hasRestored, nil
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}
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func (res *Restorer) restoreNodeTo(ctx context.Context, node *restic.Node, target, location string) error {
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if !res.opts.DryRun {
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debug.Log("restoreNode %v %v %v", node.Name, target, location)
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if err := fs.Remove(target); err != nil && !errors.Is(err, os.ErrNotExist) {
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return errors.Wrap(err, "RemoveNode")
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}
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err := node.CreateAt(ctx, target, res.repo)
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if err != nil {
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debug.Log("node.CreateAt(%s) error %v", target, err)
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return err
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}
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}
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res.opts.Progress.AddProgress(location, restoreui.ActionFileRestored, 0, 0)
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return res.restoreNodeMetadataTo(node, target, location)
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}
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func (res *Restorer) restoreNodeMetadataTo(node *restic.Node, target, location string) error {
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if res.opts.DryRun {
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return nil
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}
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debug.Log("restoreNodeMetadata %v %v %v", node.Name, target, location)
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err := node.RestoreMetadata(target, res.Warn)
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if err != nil {
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debug.Log("node.RestoreMetadata(%s) error %v", target, err)
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}
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return err
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}
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func (res *Restorer) restoreHardlinkAt(node *restic.Node, target, path, location string) error {
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if !res.opts.DryRun {
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if err := fs.Remove(path); err != nil && !errors.Is(err, os.ErrNotExist) {
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return errors.Wrap(err, "RemoveCreateHardlink")
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}
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err := fs.Link(target, path)
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if err != nil {
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return errors.WithStack(err)
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}
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}
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res.opts.Progress.AddProgress(location, restoreui.ActionFileRestored, 0, 0)
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// TODO investigate if hardlinks have separate metadata on any supported system
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return res.restoreNodeMetadataTo(node, path, location)
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}
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func (res *Restorer) ensureDir(target string) error {
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if res.opts.DryRun {
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return nil
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}
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fi, err := fs.Lstat(target)
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if err != nil && !errors.Is(err, os.ErrNotExist) {
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return fmt.Errorf("failed to check for directory: %w", err)
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}
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if err == nil && !fi.IsDir() {
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// try to cleanup unexpected file
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if err := fs.Remove(target); err != nil {
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return fmt.Errorf("failed to remove stale item: %w", err)
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}
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}
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// create parent dir with default permissions
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// second pass #leaveDir restores dir metadata after visiting/restoring all children
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return fs.MkdirAll(target, 0700)
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}
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// RestoreTo creates the directories and files in the snapshot below dst.
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// Before an item is created, res.Filter is called.
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func (res *Restorer) RestoreTo(ctx context.Context, dst string) error {
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var err error
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if !filepath.IsAbs(dst) {
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dst, err = filepath.Abs(dst)
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if err != nil {
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return errors.Wrap(err, "Abs")
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}
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}
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if !res.opts.DryRun {
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// ensure that the target directory exists and is actually a directory
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// Using ensureDir is too aggressive here as it also removes unexpected files
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if err := fs.MkdirAll(dst, 0700); err != nil {
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return fmt.Errorf("cannot create target directory: %w", err)
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}
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}
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idx := NewHardlinkIndex[string]()
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filerestorer := newFileRestorer(dst, res.repo.LoadBlobsFromPack, res.repo.LookupBlob,
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res.repo.Connections(), res.opts.Sparse, res.opts.Delete, res.opts.Progress)
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filerestorer.Error = res.Error
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debug.Log("first pass for %q", dst)
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var buf []byte
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// first tree pass: create directories and collect all files to restore
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err = res.traverseTree(ctx, dst, *res.sn.Tree, treeVisitor{
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enterDir: func(_ *restic.Node, target, location string) error {
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debug.Log("first pass, enterDir: mkdir %q, leaveDir should restore metadata", location)
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if location != "/" {
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res.opts.Progress.AddFile(0)
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}
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return res.ensureDir(target)
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},
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visitNode: func(node *restic.Node, target, location string) error {
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debug.Log("first pass, visitNode: mkdir %q, leaveDir on second pass should restore metadata", location)
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if err := res.ensureDir(filepath.Dir(target)); err != nil {
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return err
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}
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if node.Type != "file" {
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res.opts.Progress.AddFile(0)
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return nil
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}
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if node.Links > 1 {
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if idx.Has(node.Inode, node.DeviceID) {
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// a hardlinked file does not increase the restore size
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res.opts.Progress.AddFile(0)
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return nil
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}
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idx.Add(node.Inode, node.DeviceID, location)
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}
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buf, err = res.withOverwriteCheck(ctx, node, target, location, false, buf, func(updateMetadataOnly bool, matches *fileState) error {
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if updateMetadataOnly {
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res.opts.Progress.AddSkippedFile(location, node.Size)
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} else {
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res.opts.Progress.AddFile(node.Size)
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if !res.opts.DryRun {
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filerestorer.addFile(location, node.Content, int64(node.Size), matches)
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} else {
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action := restoreui.ActionFileUpdated
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if matches == nil {
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action = restoreui.ActionFileRestored
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}
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// immediately mark as completed
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res.opts.Progress.AddProgress(location, action, node.Size, node.Size)
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}
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}
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res.trackFile(location, updateMetadataOnly)
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return nil
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})
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return err
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},
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})
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if err != nil {
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return err
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}
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if !res.opts.DryRun {
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err = filerestorer.restoreFiles(ctx)
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if err != nil {
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return err
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}
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}
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debug.Log("second pass for %q", dst)
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// second tree pass: restore special files and filesystem metadata
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err = res.traverseTree(ctx, dst, *res.sn.Tree, treeVisitor{
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visitNode: func(node *restic.Node, target, location string) error {
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debug.Log("second pass, visitNode: restore node %q", location)
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if node.Type != "file" {
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_, err := res.withOverwriteCheck(ctx, node, target, location, false, nil, func(_ bool, _ *fileState) error {
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return res.restoreNodeTo(ctx, node, target, location)
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})
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return err
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}
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if idx.Has(node.Inode, node.DeviceID) && idx.Value(node.Inode, node.DeviceID) != location {
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_, err := res.withOverwriteCheck(ctx, node, target, location, true, nil, func(_ bool, _ *fileState) error {
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return res.restoreHardlinkAt(node, filerestorer.targetPath(idx.Value(node.Inode, node.DeviceID)), target, location)
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})
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return err
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}
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if _, ok := res.hasRestoredFile(location); ok {
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return res.restoreNodeMetadataTo(node, target, location)
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}
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// don't touch skipped files
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return nil
|
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},
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leaveDir: func(node *restic.Node, target, location string, expectedFilenames []string) error {
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if res.opts.Delete {
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if err := res.removeUnexpectedFiles(target, location, expectedFilenames); err != nil {
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return err
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}
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}
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if node == nil {
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return nil
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}
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|
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err := res.restoreNodeMetadataTo(node, target, location)
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if err == nil {
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res.opts.Progress.AddProgress(location, restoreui.ActionDirRestored, 0, 0)
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}
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return err
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},
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})
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return err
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}
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func (res *Restorer) removeUnexpectedFiles(target, location string, expectedFilenames []string) error {
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if !res.opts.Delete {
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panic("internal error")
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}
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entries, err := fs.Readdirnames(fs.Local{}, target, fs.O_NOFOLLOW)
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if errors.Is(err, os.ErrNotExist) {
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return nil
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} else if err != nil {
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return err
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}
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keep := map[string]struct{}{}
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for _, name := range expectedFilenames {
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keep[toComparableFilename(name)] = struct{}{}
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}
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for _, entry := range entries {
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if _, ok := keep[toComparableFilename(entry)]; ok {
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continue
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}
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nodeTarget := filepath.Join(target, entry)
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nodeLocation := filepath.Join(location, entry)
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|
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if target == nodeTarget || !fs.HasPathPrefix(target, nodeTarget) {
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return fmt.Errorf("skipping deletion due to invalid filename: %v", entry)
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}
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|
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// TODO pass a proper value to the isDir parameter once this becomes relevant for the filters
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selectedForRestore, _ := res.SelectFilter(nodeLocation, false)
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// only delete files that were selected for restore
|
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if selectedForRestore {
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res.opts.Progress.ReportDeletedFile(nodeLocation)
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if !res.opts.DryRun {
|
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if err := fs.RemoveAll(nodeTarget); err != nil {
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return err
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}
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}
|
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}
|
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}
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return nil
|
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}
|
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|
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func (res *Restorer) trackFile(location string, metadataOnly bool) {
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res.fileList[location] = metadataOnly
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}
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func (res *Restorer) hasRestoredFile(location string) (metadataOnly bool, ok bool) {
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metadataOnly, ok = res.fileList[location]
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return metadataOnly, ok
|
|
}
|
|
|
|
func (res *Restorer) withOverwriteCheck(ctx context.Context, node *restic.Node, target, location string, isHardlink bool, buf []byte, cb func(updateMetadataOnly bool, matches *fileState) error) ([]byte, error) {
|
|
overwrite, err := shouldOverwrite(res.opts.Overwrite, node, target)
|
|
if err != nil {
|
|
return buf, err
|
|
} else if !overwrite {
|
|
size := node.Size
|
|
if isHardlink {
|
|
size = 0
|
|
}
|
|
res.opts.Progress.AddSkippedFile(location, size)
|
|
return buf, nil
|
|
}
|
|
|
|
var matches *fileState
|
|
updateMetadataOnly := false
|
|
if node.Type == "file" && !isHardlink {
|
|
// if a file fails to verify, then matches is nil which results in restoring from scratch
|
|
matches, buf, _ = res.verifyFile(ctx, target, node, false, res.opts.Overwrite == OverwriteIfChanged, buf)
|
|
// skip files that are already correct completely
|
|
updateMetadataOnly = !matches.NeedsRestore()
|
|
}
|
|
|
|
return buf, cb(updateMetadataOnly, matches)
|
|
}
|
|
|
|
func shouldOverwrite(overwrite OverwriteBehavior, node *restic.Node, destination string) (bool, error) {
|
|
if overwrite == OverwriteAlways || overwrite == OverwriteIfChanged {
|
|
return true, nil
|
|
}
|
|
|
|
fi, err := fs.Lstat(destination)
|
|
if err != nil {
|
|
if errors.Is(err, os.ErrNotExist) {
|
|
return true, nil
|
|
}
|
|
return false, err
|
|
}
|
|
|
|
if overwrite == OverwriteIfNewer {
|
|
// return if node is newer
|
|
return node.ModTime.After(fi.ModTime()), nil
|
|
} else if overwrite == OverwriteNever {
|
|
// file exists
|
|
return false, nil
|
|
}
|
|
panic("unknown overwrite behavior")
|
|
}
|
|
|
|
// Snapshot returns the snapshot this restorer is configured to use.
|
|
func (res *Restorer) Snapshot() *restic.Snapshot {
|
|
return res.sn
|
|
}
|
|
|
|
// Number of workers in VerifyFiles.
|
|
const nVerifyWorkers = 8
|
|
|
|
// VerifyFiles checks whether all regular files in the snapshot res.sn
|
|
// have been successfully written to dst. It stops when it encounters an
|
|
// error. It returns that error and the number of files it has successfully
|
|
// verified.
|
|
func (res *Restorer) VerifyFiles(ctx context.Context, dst string) (int, error) {
|
|
type mustCheck struct {
|
|
node *restic.Node
|
|
path string
|
|
}
|
|
|
|
var (
|
|
nchecked uint64
|
|
work = make(chan mustCheck, 2*nVerifyWorkers)
|
|
)
|
|
|
|
g, ctx := errgroup.WithContext(ctx)
|
|
|
|
// Traverse tree and send jobs to work.
|
|
g.Go(func() error {
|
|
defer close(work)
|
|
|
|
err := res.traverseTree(ctx, dst, *res.sn.Tree, treeVisitor{
|
|
visitNode: func(node *restic.Node, target, location string) error {
|
|
if node.Type != "file" {
|
|
return nil
|
|
}
|
|
if metadataOnly, ok := res.hasRestoredFile(location); !ok || metadataOnly {
|
|
return nil
|
|
}
|
|
select {
|
|
case <-ctx.Done():
|
|
return ctx.Err()
|
|
case work <- mustCheck{node, target}:
|
|
return nil
|
|
}
|
|
},
|
|
})
|
|
return err
|
|
})
|
|
|
|
for i := 0; i < nVerifyWorkers; i++ {
|
|
g.Go(func() (err error) {
|
|
var buf []byte
|
|
for job := range work {
|
|
_, buf, err = res.verifyFile(ctx, job.path, job.node, true, false, buf)
|
|
err = res.sanitizeError(job.path, err)
|
|
if err != nil || ctx.Err() != nil {
|
|
break
|
|
}
|
|
atomic.AddUint64(&nchecked, 1)
|
|
}
|
|
return err
|
|
})
|
|
}
|
|
|
|
return int(nchecked), g.Wait()
|
|
}
|
|
|
|
type fileState struct {
|
|
blobMatches []bool
|
|
sizeMatches bool
|
|
}
|
|
|
|
func (s *fileState) NeedsRestore() bool {
|
|
if s == nil {
|
|
return true
|
|
}
|
|
if !s.sizeMatches {
|
|
return true
|
|
}
|
|
for _, match := range s.blobMatches {
|
|
if !match {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
func (s *fileState) HasMatchingBlob(i int) bool {
|
|
if s == nil || s.blobMatches == nil {
|
|
return false
|
|
}
|
|
return i < len(s.blobMatches) && s.blobMatches[i]
|
|
}
|
|
|
|
// Verify that the file target has the contents of node.
|
|
//
|
|
// buf and the first return value are scratch space, passed around for reuse.
|
|
// Reusing buffers prevents the verifier goroutines allocating all of RAM and
|
|
// flushing the filesystem cache (at least on Linux).
|
|
func (res *Restorer) verifyFile(ctx context.Context, target string, node *restic.Node, failFast bool, trustMtime bool, buf []byte) (*fileState, []byte, error) {
|
|
f, err := fs.OpenFile(target, fs.O_RDONLY|fs.O_NOFOLLOW, 0)
|
|
if err != nil {
|
|
return nil, buf, err
|
|
}
|
|
defer func() {
|
|
_ = f.Close()
|
|
}()
|
|
|
|
fi, err := f.Stat()
|
|
sizeMatches := true
|
|
switch {
|
|
case err != nil:
|
|
return nil, buf, err
|
|
case !fi.Mode().IsRegular():
|
|
return nil, buf, errors.Errorf("Expected %s to be a regular file", target)
|
|
case int64(node.Size) != fi.Size():
|
|
if failFast {
|
|
return nil, buf, errors.Errorf("Invalid file size for %s: expected %d, got %d",
|
|
target, node.Size, fi.Size())
|
|
}
|
|
sizeMatches = false
|
|
}
|
|
|
|
if trustMtime && fi.ModTime().Equal(node.ModTime) && sizeMatches {
|
|
return &fileState{nil, sizeMatches}, buf, nil
|
|
}
|
|
|
|
matches := make([]bool, len(node.Content))
|
|
var offset int64
|
|
for i, blobID := range node.Content {
|
|
if ctx.Err() != nil {
|
|
return nil, buf, ctx.Err()
|
|
}
|
|
length, found := res.repo.LookupBlobSize(restic.DataBlob, blobID)
|
|
if !found {
|
|
return nil, buf, errors.Errorf("Unable to fetch blob %s", blobID)
|
|
}
|
|
|
|
if length > uint(cap(buf)) {
|
|
buf = make([]byte, 2*length)
|
|
}
|
|
buf = buf[:length]
|
|
|
|
_, err = f.ReadAt(buf, offset)
|
|
if err == io.EOF && !failFast {
|
|
sizeMatches = false
|
|
break
|
|
}
|
|
if err != nil {
|
|
return nil, buf, err
|
|
}
|
|
matches[i] = blobID.Equal(restic.Hash(buf))
|
|
if failFast && !matches[i] {
|
|
return nil, buf, errors.Errorf(
|
|
"Unexpected content in %s, starting at offset %d",
|
|
target, offset)
|
|
}
|
|
offset += int64(length)
|
|
}
|
|
|
|
return &fileState{matches, sizeMatches}, buf, nil
|
|
}
|