mobile-nixos/boot/init/tasks/udev.rb

# Runs udev daemon
class Tasks::UDev < SingletonTask
  def initialize()
    add_dependency(:Target, :Environment)
    add_dependency(:Mount, "/dev")
    add_dependency(:Mount, "/proc")
    add_dependency(:Mount, "/run")
    add_dependency(:Mount, "/sys")

    # Make the Devices target depend on this task.
    # It is preferred to depend on the specific device rather than this target.
    Targets[:Devices].add_dependency(:Task, self)
  end

  def udevadm(*args)
    System.run("udevadm", *args)
  end

  def run()
    udevd
    udevadm("trigger", "--action=add")
    udevadm("settle")
  end

  def udevd()
    *args = []
    args << "--debug" if debug?
    System.run("systemd-udevd", "--daemon", *args)
  end

  # TODO: Allow configuring its debug state
  def debug?
    false
  end

  # TODO: teardown
  #         udevadm control --exit
end