func main() {
flag.Parse()
if flag.NArg() != 1 {
fmt.Printf("Usage: xray FILE\n")
os.Exit(1)
}
f := flag.Arg(0)
fd, err := os.Open(f)
if err != nil {
errExit(err)
}
headerBytes := make([]byte, contentenc.HeaderLen)
n, err := fd.ReadAt(headerBytes, 0)
if err == io.EOF && n == 0 {
fmt.Println("empty file")
os.Exit(0)
} else if err == io.EOF {
fmt.Printf("incomplete file header: read %d bytes, want %d\n", n, contentenc.HeaderLen)
os.Exit(1)
} else if err != nil {
errExit(err)
}
header, err := contentenc.ParseHeader(headerBytes)
if err != nil {
errExit(err)
}
prettyPrintHeader(header)
var i int64
for i = 0; ; i++ {
blockLen := int64(blockSize)
off := contentenc.HeaderLen + i*blockSize
iv := make([]byte, ivLen)
_, err := fd.ReadAt(iv, off)
if err == io.EOF {
break
} else if err != nil {
errExit(err)
}
tag := make([]byte, cryptocore.AuthTagLen)
_, err = fd.ReadAt(tag, off+blockSize-cryptocore.AuthTagLen)
if err == io.EOF {
fi, err2 := fd.Stat()
if err2 != nil {
errExit(err2)
}
_, err2 = fd.ReadAt(tag, fi.Size()-cryptocore.AuthTagLen)
if err2 != nil {
errExit(err2)
}
blockLen = (fi.Size() - contentenc.HeaderLen) % blockSize
} else if err != nil {
errExit(err)
}
fmt.Printf("Block %2d: IV: %s, Tag: %s, Offset: %5d Len: %d\n",
i, hex.EncodeToString(iv), hex.EncodeToString(tag), off, blockLen)
}
}
// readFileID loads the file header from disk and extracts the file ID.
// Returns io.EOF if the file is empty.
func (f *file) readFileID() ([]byte, error) {
buf := make([]byte, contentenc.HeaderLen)
_, err := f.fd.ReadAt(buf, 0)
if err != nil {
return nil, err
}
h, err := contentenc.ParseHeader(buf)
if err != nil {
return nil, err
}
return h.ID, nil
}