Windows: Updates Windows Vendoring

Updates windows dependent libraries for vendoing.

vendor/github.com/Microsoft/hcsshim/ext4/tar2ext4/vhdfooter.go

@@ -0,0 +1,76 @@
+package tar2ext4
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/binary"
+)
+
+// Constants for the VHD footer
+const (
+	cookieMagic            = "conectix"
+	featureMask            = 0x2
+	fileFormatVersionMagic = 0x00010000
+	fixedDataOffset        = -1
+	creatorVersionMagic    = 0x000a0000
+	diskTypeFixed          = 2
+)
+
+type vhdFooter struct {
+	Cookie             [8]byte
+	Features           uint32
+	FileFormatVersion  uint32
+	DataOffset         int64
+	TimeStamp          uint32
+	CreatorApplication [4]byte
+	CreatorVersion     uint32
+	CreatorHostOS      [4]byte
+	OriginalSize       int64
+	CurrentSize        int64
+	DiskGeometry       uint32
+	DiskType           uint32
+	Checksum           uint32
+	UniqueID           [16]uint8
+	SavedState         uint8
+	Reserved           [427]uint8
+}
+
+func makeFixedVHDFooter(size int64) *vhdFooter {
+	footer := &vhdFooter{
+		Features:          featureMask,
+		FileFormatVersion: fileFormatVersionMagic,
+		DataOffset:        fixedDataOffset,
+		CreatorVersion:    creatorVersionMagic,
+		OriginalSize:      size,
+		CurrentSize:       size,
+		DiskType:          diskTypeFixed,
+		UniqueID:          generateUUID(),
+	}
+	copy(footer.Cookie[:], cookieMagic)
+	footer.Checksum = calculateCheckSum(footer)
+	return footer
+}
+
+func calculateCheckSum(footer *vhdFooter) uint32 {
+	oldchk := footer.Checksum
+	footer.Checksum = 0
+
+	buf := &bytes.Buffer{}
+	binary.Write(buf, binary.BigEndian, footer)
+
+	var chk uint32
+	bufBytes := buf.Bytes()
+	for i := 0; i < len(bufBytes); i++ {
+		chk += uint32(bufBytes[i])
+	}
+	footer.Checksum = oldchk
+	return uint32(^chk)
+}
+
+func generateUUID() [16]byte {
+	res := [16]byte{}
+	if _, err := rand.Read(res[:]); err != nil {
+		panic(err)
+	}
+	return res
+}