package main

import "syscall"

func diskUsage(path string) float64 {
	var stat syscall.Statfs_t
	if err := syscall.Statfs(path, &stat); err != nil {
		return 0
	}
	total := stat.Blocks * uint64(stat.Bsize)
	free := stat.Bavail * uint64(stat.Bsize)
	if total == 0 {
		return 0
	}
	return float64(total-free) / float64(total)
}