package main

import (
	"fmt"
	"unsafe"

	"golang.org/x/sys/unix"
)

const (
	RNDGETENTCNT int = 0x80045200
)

func main() {
	var (
		fd  int
		err error
	)

	if fd, err = unix.Open("/dev/random", unix.O_RDONLY, 0); err != nil {
		fmt.Printf("Error: %v\n", err)
	}
	defer unix.Close(fd)

	var (
		ent int
	)
	_, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(fd), uintptr(RNDGETENTCNT), uintptr(unsafe.Pointer(&ent)))
	if errno != 0 {
		fmt.Printf("Error: %v\n", errno)
	}

	fmt.Printf("Available Entropy: %v\n", ent)
}