This Python module contains some simple helper functions for calling fcntl.ioctl().
import ctypes import os import ioctl import ioctl.linux RNDGETENTCNT = ioctl.linux.IOR('R', 0x00, ctypes.c_int) rndgetentcnt = ioctl.ioctl_fn_ptr_r(RNDGETENTCNT, ctypes.c_int) fd = os.open('/dev/random', os.O_RDONLY) entropy_avail = rndgetentcnt(fd) print('entropy_avail:', entropy_avail)