cmd/torrent-verify/main.go

   1 package main
   2
   3 import (
   4         "bytes"
   5         "crypto/sha1"
   6         "flag"
   7         "fmt"
   8         "log"
   9         "os"
  10         "path/filepath"
  11
  12         "launchpad.net/gommap"
  13
  14         "github.com/anacrolix/torrent/metainfo"
  15         "github.com/anacrolix/torrent/mmap_span"
  16 )
  17
  18 var (
  19         filePath = flag.String("torrent", "/path/to/the.torrent", "path of the torrent file")
  20         dirPath  = flag.String("path", "/torrent/data", "path of the torrent data")
  21 )
  22
  23 func init() {
  24         flag.Parse()
  25 }
  26
  27 func main() {
  28         metaInfo, err := metainfo.LoadFromFile(*filePath)
  29         if err != nil {
  30                 log.Fatal(err)
  31         }
  32         devZero, err := os.Open("/dev/zero")
  33         if err != nil {
  34                 log.Print(err)
  35         }
  36         defer devZero.Close()
  37         var mMapSpan *mmap_span.MMapSpan
  38         for _, file := range metaInfo.Info.Files {
  39                 filename := filepath.Join(append([]string{*dirPath, metaInfo.Info.Name}, file.Path...)...)
  40                 osFile, err := os.Open(filename)
  41                 mmapFd := osFile.Fd()
  42                 if err != nil {
  43                         if pe, ok := err.(*os.PathError); ok && pe.Err.Error() == "no such file or directory" {
  44                                 mmapFd = devZero.Fd()
  45                         } else {
  46                                 log.Fatal(err)
  47                         }
  48                 }
  49                 goMMap, err := gommap.MapRegion(mmapFd, 0, file.Length, gommap.PROT_READ, gommap.MAP_PRIVATE)
  50                 if err != nil {
  51                         log.Fatal(err)
  52                 }
  53                 if int64(len(goMMap)) != file.Length {
  54                         log.Printf("file mmap has wrong size: %#v", filename)
  55                 }
  56                 osFile.Close()
  57                 mMapSpan.Append(goMMap)
  58         }
  59         log.Println(len(metaInfo.Info.Files))
  60         log.Println(mMapSpan.Size())
  61         log.Println(len(metaInfo.Info.Pieces))
  62         for piece := 0; piece < (len(metaInfo.Info.Pieces)+sha1.Size-1)/sha1.Size; piece++ {
  63                 expectedHash := metaInfo.Info.Pieces[sha1.Size*piece : sha1.Size*(piece+1)]
  64                 if len(expectedHash) == 0 {
  65                         break
  66                 }
  67                 hash := sha1.New()
  68                 _, err := mMapSpan.WriteSectionTo(hash, int64(piece)*metaInfo.Info.PieceLength, metaInfo.Info.PieceLength)
  69                 if err != nil {
  70                         log.Fatal(err)
  71                 }
  72                 fmt.Println(piece, bytes.Equal(hash.Sum(nil), expectedHash))
  73         }
  74 }