Add torrent-verify, simple exe that logs matching pieces from a torrent file and...

diff --git a/cmd/torrent-verify/main.go b/cmd/torrent-verify/main.go
new file mode 100644 (file)
index 0000000..7259f0e
--- /dev/null
+++ b/cmd/torrent-verify/main.go
@@ -0,0 +1,75 @@
+package main
+
+import (
+       "bitbucket.org/anacrolix/go.torrent"
+       "bytes"
+       "crypto/sha1"
+       "flag"
+       metainfo "github.com/nsf/libtorgo/torrent"
+       "io"
+       "launchpad.net/gommap"
+       "log"
+       "os"
+       "path/filepath"
+)
+
+var (
+       filePath = flag.String("torrent", "/path/to/the.torrent", "path of the torrent file")
+       dirPath  = flag.String("path", "/torrent/data", "path of the torrent data")
+)
+
+func init() {
+       flag.Parse()
+}
+
+func main() {
+       metaInfo, err := metainfo.LoadFromFile(*filePath)
+       if err != nil {
+               log.Fatal(err)
+       }
+       devZero, err := os.Open("/dev/zero")
+       if err != nil {
+               log.Print(err)
+       }
+       defer devZero.Close()
+       var mmapSpan torrent.MmapSpan
+       for _, file := range metaInfo.Files {
+               filename := filepath.Join(append([]string{*dirPath, metaInfo.Name}, file.Path...)...)
+               osFile, err := os.Open(filename)
+               mmapFd := osFile.Fd()
+               if err != nil {
+                       if pe, ok := err.(*os.PathError); ok && pe.Err.Error() == "no such file or directory" {
+                               mmapFd = devZero.Fd()
+                       } else {
+                               log.Fatal(err)
+                       }
+               }
+               goMMap, err := gommap.MapRegion(mmapFd, 0, file.Length, gommap.PROT_READ, gommap.MAP_PRIVATE)
+               if err != nil {
+                       log.Fatal(err)
+               }
+               if int64(len(goMMap)) != file.Length {
+                       log.Printf("file mmap has wrong size: %#v", filename)
+               }
+               osFile.Close()
+               mmapSpan = append(mmapSpan, torrent.Mmap{goMMap})
+       }
+       log.Println(len(metaInfo.Files))
+       log.Println(mmapSpan.Size())
+       log.Println(len(metaInfo.Pieces))
+       for piece := int64(0); ; piece++ {
+               expectedHash := metaInfo.Pieces[sha1.Size*piece : sha1.Size*(piece+1)]
+               if len(expectedHash) == 0 {
+                       break
+               }
+               hash := sha1.New()
+               n, err := io.Copy(hash, io.NewSectionReader(mmapSpan, piece*metaInfo.PieceLength, metaInfo.PieceLength))
+               if n != metaInfo.PieceLength {
+                       panic("oh no")
+               }
+               if err != nil {
+                       log.Fatal(err)
+               }
+               log.Println(piece, bytes.Equal(hash.Sum(nil), expectedHash))
+       }
+}