One of the interesting undocumented features of android is the inclusion of the ioctl command line utility in toolbox.
ioctl.c - Source code modified to compile under Ubuntu.
Without having to compile code for different architectures, you can generate ioctl's on any Android Linux platform.
This opens the door to lower-level kernel access from within apps.
The android ioctl app
This app includes a list of common ioctls (with their hex codes) for easy prototyping.
While this app can work with non-rooted devices, most device special files require superuser permissions.