#devices #linux #emulation #userspace #fuse #input #evdev

southpaw

Allows userspace emulation of evdev character devices

1 unstable release

0.1.0 Sep 8, 2024

#370 in Unix APIs

Download history 111/week @ 2024-09-06 28/week @ 2024-09-13 18/week @ 2024-09-20 20/week @ 2024-09-27

177 downloads per month

MIT license

75KB
2K SLoC

Southpaw

tests docs

This is a crate that lets you emulate linux evdev character devices completely in userspace, using FUSE.

Why would I want to do that?

Linux has good support for emulating input devices, with uinput. However, it suffers from a few drawbacks:

  • It doesn't hew to any sort of namespacing, and the devices it emulates are global to the system. That makes it difficult to use inside containers.
  • Because of the above, it usually requires elevated privileges.

Because FUSE mounts can be used inside mount namespaces, southpaw lets you simulate input devices in rootless containers, without even needing root inside the container.

Features

The following ioctls are currently implemented:

Ioctl Support
EVIOCGVERSION
EVIOCGID
EVIOCGREP
EVIOCSREP
EVIOCGKEYCODE
EVIOCGKEYCODE_V2
EVIOCSKEYCODE
EVIOCSKEYCODE_V2
EVIOCGNAME
EVIOCGPHYS
EVIOCGUNIQ
EVIOCGPROP
EVIOCGMTSLOTS
EVIOCGKEY
EVIOCGLED
EVIOCGSND
EVIOCGSW
EVIOCGBIT
EVIOCGABS
EVIOCSABS
EVIOCSFF
EVIOCGRMFF
EVIOCGEFFECTS
EVIOCGRAB
EVIOCREVOKE
EVIOCGMASK
EVIOCSMASK
EVIOCSCLOCKID
EVIOCGVERSION
EVIOCGVERSION

Basic reading and publishing events is supported, both for blocking and non-blocking readers. Force feedback is not supported yet.

Dependencies

~7–19MB
~275K SLoC