evdev: export event device properties through sysctl interface
A big security advantage of Wayland is not allowing applications to read
input devices all the time. Having /dev/input/* accessible to the user
account subverts this advantage.
libudev-devd was opening the evdev devices to detect their types (mouse,
keyboard, touchpad, etc). This don't work if /dev/input/* is inaccessible.
With the kernel exposing this information as sysctls (kern.evdev.input.*),
we can work w/o /dev/input/* access, preserving the Wayland security model.
Submitted by: Greg V <greg@unrelenting.technology>
Reviewed by: wulf, imp
Differential Revision: https://reviews.freebsd.org/D18694
9991baca94