Function to allow access to host devices from a container

container_devices

function permit_device_control() {
  local devices_mount_info=$(cat /proc/self/cgroup | grep devices)
  local devices_subsytems=$(echo $devices_mount_info | cut -d: -f2)
  local devices_subdir=$(echo $devices_mount_info | cut -d: -f3)

  if [ ! -e /tmp/devices-cgroup ]; then
    mkdir /tmp/devices-cgroup
    mount -t cgroup -o $devices_subsytems none /tmp/devices-cgroup
  fi

  echo a > /tmp/devices-cgroup${devices_subdir}/devices.allow || true
  umount /tmp/devices-cgroup || true
}