Wayland on OpenBSD

Introduction

These are my notes from experimenting with building Wayland bits on OpenBSD during g2k23 in Tallinn… Thanks to the OpenBSD foundation for organizing this event.

This is still far from a complete running system as there are many issues on the road, but it’s a good start and it shows that it’s definatly not impossible to get Wayland running on OpenBSD.

Updated to reflect that all of this in now a work in progress set of ports

Disclaimers

I don’t know much about Wayland internals, I’m discovering that on the way, so some stuff here may look naive or totally wrong to experimented Wayland developers…
I’m not discussing here on why Wayland ? You may find some answers in this paper I wrote in 2017 (in french).
The build instructions below will probably break your system. Use a separate machine for this

General ideas

I’m using the wlroots library and will focus on compositors (sway, tinywl+…) and applications that use it
- Gnome (GTK+) based or Qt-based application will wait until someone else builds Wayland support for those toolkits on OpenBSD
The output path is more or less ready with the DRI and Mesa porting efforts (mostly jsg and kettenis)
- jsg’s github fork of mesa is being used to build it using meson. This may not be needed, but I haven’t checked
“Seat” management is going to be minimal, as OpenBSD doesn’t support this:
- seatd and libseat provide support for non-systemd based systems. A basic port to OpenBSD/wscons is needed.
Input is more complex to get working since Wayland applications expect Linux input model with udev, evdev and libinput.
- udev is used to probe available device and handle hot-plugging on Linux. OpenBSD doesn’t have it and the current state of hotplugd(8) doesn’t make it possible to really emulate udev. There is a libudev-openbsd port already that can be used.
- evdev is the input event layer of the Linux kernel, similar to wscons_events in OpenBSD. It’s mostly hidden by libinput, but event name translation need the libevdev library for some reason.
- libinput is the library that permits reading evdev events from the Linux kernel and handling many of the higher level interpretation of the events (getting the keyboard mapping, mouse gestures or multi-touch)… It also handles device configuration. mpi did a simple libinput port back in 2015, and rsadowski improved it a bit in 2022. More work is needed.

All this works on top of existing Xenocara and ports.

Available ports

All needed ports are available on this repository.
This can be cloned into mystuff to build and install the packages over and existing ports tree.

cd /usr/ports
git clone https://gitlab.tetaneutral.net/mherrb/wl-ports.git mystuff
cd mystuff/wayland/sway
make install

sysutils/seatd

The original project in on Source Hut

The OpenBSD port is very minimal but enough for now. TODO: make it more complete WRT VT switching, using fbtab and some sort of session management.

devel/libinput-openbsd

This is the version from mpi@, patched@ by radowski, plus extra udev code from me.
I’ve now added proper events translation (for mouse buttons and keyboard) so that the input works in a usable way in Wayland.

sysutils/libevdev-openbsd

This is a stripped-down version of libevdev, providing just the few functions to handle name to symbol conversions that are used by most Wayland applications.

sysutils/libdisplay-info and graphics/libliftoff

Those two small helper libraries build of of the box on OpenBSD. I’ve made ports for them in my xenoports tree, or they can be built from gitlab:

wayland/xwayland

It’s a straightforward port of the upstream release.

wayland/wlroots

A version of wlroots that has been patched for OpenBSD. The wscons backend code can dropped for now. I’m not sure if it will ever be possible to have Wayland applications running without libinput (but that’s the goal of this backend).

wayland/havoc

Havoc is the simplest terminal emulator application for Wayland that I could find and that builds on OpenBSD with minimal changes.

wayland/sway

Sway is a tiled Wayland compositor, compatible with i3, ported to OpenBSD

swayimg

TODO : port

An image viewer for Wayland that builds on OpenBSD without patches \o/

git clone https://github.com/artemsen/swayimg.git
cd swayimg 
meson setup build
ninja -C build
doas -C build ninja install

Default cursor theme

Wayland doesn’t provide cursors by itself. So one needs to install the gnome-icon-theme package or any other package providing a default theme.
Because of the cursor path mentionned above, link /usr/local/share/icons to ~/.icons for now to get cursors.

Note: swaybar used to segfault if it’s missing a cursor, it should be fixed in the current port

Fonts

Wayland is using fontconfig. So it can use any fonts installed via pkg_add swaybar expects the terminus font to be available.

Running Wayland

One needs to set a number of environment variables. The following script (runwl) helps:

#! /bin/ksh
export XDG_RUNTIME_DIR=/tmp 
export WAYLAND_DISPLAY=wayland-0
exec $*

Start seatd

This gives the /var/run/seatd.sock to my user, so that the applications will be run as my uid, not root.
```
 doas seatd -u $(whoami) -l debug
```

Start sway:

 export XDG_RUNTIME_DIR=/tmp 
 export WLR_DRM_DEVICES=/dev/dri/card0
 sway

start an application (here havoc)
```
 runwl havoc
```

X Applications

Sway starts Xwayland automatically if an application needs X

It can also be started manually, but not in rootless mode (this is a Wayland security feature). X applications work in the Xwaylan in windowed mode, but OpenGL X applications crash (probably because of mismatched Mesa versions in my builds FIXME

More work to do

Gtk applications

Simple patches allows to build gtk+3 and gtk+4 with wayland support enabled. gtk3-demo works, built against the patched version.

Note that both emacs and mozilla-firefox work, but still use Xwayland. The ports need some plist and lib-depends patches once wayland support is enabled in gtk+3/4.

So far gtk4-demos fails to start, it still tries to connect to an X serer and segfault. FIXME

Qt applications

Qt 5 and 6 are normally built with Wayland support. I tried keepassxc(1) (Qt5) which could’nt connect to the compositor. qt6/qtbase doesn’t build on my system from some reason. FIXME

<uchar.h> and char32_t

A number of Wayland applications use UTF-32 internally and require support for the above that it not (yet) available on OpenBSD. TODO: one implementation exists in DragonFlyBSD.
Thay would probably unlock foot and others.

swaylock

To get a screen locker, swaylock needs to be tought about BSD auth to replace PAM.

Pledge and Unveil

None of the above currenty implement pledge() or unveil() support, nor any other from of sandboxing afaict. This could be looked at at some point.

Known issues

Sway sometimes crashes on startup because of a use after free error happening somewhere in fontconfig.
Sway will crash the kernel during startup from time to time. I don’t know if it’s a problem specific to the dri driver for the Intel iris (12th gen) GPU in my test laptop or a general bug. TODO: test on a machine with a serial console to get a backtrace if possible.

Last modified: 2023-07-16T19:21:00