2
2
mirror of https://github.com/octoleo/restic.git synced 2024-11-05 21:07:52 +00:00

debug: check packs not in index, implement repair

This commit is contained in:
Alexander Neumann 2018-09-29 14:16:01 +02:00 committed by Michael Eischer
parent d6f78163d4
commit 086993bae1

View File

@ -8,10 +8,14 @@ import (
"fmt"
"io"
"os"
"runtime"
"sort"
"time"
"github.com/spf13/cobra"
"golang.org/x/sync/errgroup"
"github.com/restic/restic/internal/crypto"
"github.com/restic/restic/internal/errors"
"github.com/restic/restic/internal/pack"
"github.com/restic/restic/internal/repository"
@ -41,10 +45,13 @@ Exit status is 0 if the command was successful, and non-zero if there was any er
},
}
var tryRepair bool
func init() {
cmdRoot.AddCommand(cmdDebug)
cmdDebug.AddCommand(cmdDebugDump)
cmdDebug.AddCommand(cmdDebugExamine)
cmdDebugExamine.Flags().BoolVar(&tryRepair, "try-repair", false, "try to repair broken blobs with single bit flips")
}
func prettyPrintJSON(wr io.Writer, item interface{}) error {
@ -178,7 +185,87 @@ var cmdDebugExamine = &cobra.Command{
},
}
func loadBlobs(ctx context.Context, repo restic.Repository, pack string, list []restic.PackedBlob) error {
func tryRepairWithBitflip(ctx context.Context, key *crypto.Key, input []byte) {
fmt.Printf(" trying to repair blob with single bit flip\n")
ch := make(chan int)
var wg errgroup.Group
done := make(chan struct{})
fmt.Printf(" spinning up %d worker functions\n", runtime.NumCPU())
for i := 0; i < runtime.NumCPU(); i++ {
wg.Go(func() error {
// make a local copy of the buffer
buf := make([]byte, len(input))
copy(buf, input)
for {
select {
case <-done:
return nil
case i := <-ch:
for j := 0; j < 7; j++ {
// flip bit
buf[i] ^= (1 << uint(j))
nonce, plaintext := buf[:key.NonceSize()], buf[key.NonceSize():]
plaintext, err := key.Open(plaintext[:0], nonce, plaintext, nil)
if err == nil {
fmt.Printf("\n")
fmt.Printf(" blob could be repaired by flipping bit %v in byte %v\n", j, i)
fmt.Printf(" hash is %v\n", restic.Hash(plaintext))
close(done)
return nil
}
// flip bit back
buf[i] ^= (1 << uint(j))
}
}
}
})
}
start := time.Now()
info := time.Now()
outer:
for i := range input {
select {
case ch <- i:
case <-done:
fmt.Printf(" done after %v\n", time.Since(start))
break outer
}
if time.Since(info) > time.Second {
secs := time.Since(start).Seconds()
gps := float64(i) / secs
remaining := len(input) - i
eta := time.Duration(float64(remaining)/gps) * time.Second
fmt.Printf("\r%d byte of %d done (%.2f%%), %.2f guesses per second, ETA %v",
i, len(input), float32(i)/float32(len(input)),
gps, eta)
info = time.Now()
}
}
var found bool
select {
case <-done:
found = true
default:
close(done)
}
wg.Wait()
if !found {
fmt.Printf("\n blob could not be repaired by single bit flip\n")
}
}
func loadBlobs(ctx context.Context, repo restic.Repository, pack string, list []restic.Blob) error {
be := repo.Backend()
for _, blob := range list {
fmt.Printf(" loading blob %v at %v (length %v)\n", blob.ID, blob.Offset, blob.Length)
@ -202,15 +289,18 @@ func loadBlobs(ctx context.Context, repo restic.Repository, pack string, list []
key := repo.Key()
nonce, buf := buf[:key.NonceSize()], buf[key.NonceSize():]
buf, err = key.Open(buf[:0], nonce, buf, nil)
nonce, plaintext := buf[:key.NonceSize()], buf[key.NonceSize():]
plaintext, err = key.Open(plaintext[:0], nonce, plaintext, nil)
if err != nil {
fmt.Fprintf(os.Stderr, "error decrypting blob: %v\n", err)
if tryRepair {
tryRepairWithBitflip(ctx, key, buf)
}
continue
}
id := restic.Hash(buf)
fmt.Printf(" successfully decrypted blob (length %v), hash is %v\n", len(buf), id)
id := restic.Hash(plaintext)
fmt.Printf(" successfully decrypted blob (length %v), hash is %v\n", len(plaintext), id)
if !id.Equal(blob.ID) {
fmt.Printf(" IDs do not match, want %v, got %v\n", blob.ID, id)
} else {
@ -240,6 +330,7 @@ func runDebugExamine(gopts GlobalOptions, args []string) error {
return err
}
blobsLoaded := false
for _, name := range args {
fmt.Printf("examine %v\n", name)
id, err := restic.ParseID(name)
@ -257,6 +348,8 @@ func runDebugExamine(gopts GlobalOptions, args []string) error {
}
fmt.Printf(" file size is %v\n", fi.Size)
fmt.Printf(" ========================================\n")
fmt.Printf(" looking for info in the indexes\n")
// examine all data the indexes have for the pack file
for _, idx := range repo.Index().(*repository.MasterIndex).All() {
@ -267,7 +360,6 @@ func runDebugExamine(gopts GlobalOptions, args []string) error {
blobs := idx.ListPack(id)
if len(blobs) == 0 {
fmt.Printf(" index %v does not contain the file\n", idxIDs)
continue
}
@ -300,13 +392,23 @@ func runDebugExamine(gopts GlobalOptions, args []string) error {
fmt.Printf(" file sizes match\n")
}
err = loadBlobs(gopts.ctx, repo, name, blobs)
// convert list of blobs to []restic.Blob
var list []restic.Blob
for _, b := range blobs {
list = append(list, b.Blob)
}
err = loadBlobs(gopts.ctx, repo, name, list)
if err != nil {
fmt.Fprintf(os.Stderr, "error: %v\n", err)
} else {
blobsLoaded = true
}
}
// inspect the pack file itself
fmt.Printf(" ========================================\n")
fmt.Printf(" inspect the pack itself\n")
blobs, _, err := pack.List(repo.Key(), restic.ReaderAt(gopts.ctx, repo.Backend(), h), fi.Size)
if err != nil {
fmt.Fprintf(os.Stderr, "error for pack %v: %v\n", id.Str(), err)
@ -339,6 +441,13 @@ func runDebugExamine(gopts GlobalOptions, args []string) error {
} else {
fmt.Printf(" file sizes match\n")
}
if !blobsLoaded {
err = loadBlobs(gopts.ctx, repo, name, blobs)
if err != nil {
fmt.Fprintf(os.Stderr, "error: %v\n", err)
}
}
}
return nil
}