// chance the file doesn't exist yet - keeps the number of tries in
// TempFile to a minimum.
//
//go:linkname runtime_rand runtime.rand
func runtime_rand() uint64

func nextRandom() string {
	return itoa.Uitoa(uint(uint32(runtime_rand())))
}

// CreateTemp creates a new temporary file in the directory dir,
// opens the file for reading and writing, and returns the resulting file.

	k := nm1.trailingZeroBits()
	q := nat(nil).shr(nm1, k)

	nm3 := nat(nil).sub(nm1, natTwo)
	rand := rand.New(rand.NewSource(int64(n[0])))

	var x, y, quotient nat
	nm3Len := nm3.bitLen()

NextRandom:
	for i := 0; i < reps; i++ {
		if i == reps-1 && force2 {
			x = x.set(natTwo)
		} else {
			x = x.random(rand, nm3, nm3Len)
			x = x.add(x, natTwo)
		}
		y = y.expNN(x, q, n, false)

	fdSem <- true
	defer func() { <-fdSem }()

	nextRandom := func() string {
		return strconv.Itoa(rand.Int())
	}

	dir, base := filepath.Split(filename)
	var (
		bakname string
		f       *os.File
	)
	for {
		bakname = filepath.Join(dir, base+"."+nextRandom())
		var err error
		f, err = os.OpenFile(bakname, os.O_RDWR|os.O_CREATE|os.O_EXCL, perm)