**Related issue:** Resolves#31633.
Main change is stop relying on `who` command output to get the value of
the DISPLAY variable on X11 sessions (old distributions), and instead
search the value of the `DISPLAY` variable in processes that are owned
by the target user.
- [X] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
## Testing
- [x] QA'd all new/changed functionality manually
## fleetd/orbit/Fleet Desktop
- [x] Verified compatibility with the latest released version of Fleet
(see [Must
rule](https://github.com/fleetdm/fleet/blob/main/docs/Contributing/workflows/fleetd-development-and-release-strategy.md))
- [x] If the change applies to only one platform, confirmed that
`runtime.GOOS` is used as needed to isolate changes
- [x] Verified that fleetd runs on macOS, Linux and Windows
- [x] Verified auto-update works from the released version of component
to the new version (see [tools/tuf/test](../tools/tuf/test/README.md))
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Bug Fixes**
* Enhanced X11 session detection for improved support in multi-session
environments, providing more reliable display variable identification in
complex session configurations.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
For #19043.
See the versions and distributions tested during development on the QA
notes of #19043.
---
- [X] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
See [Changes
files](https://github.com/fleetdm/fleet/blob/main/docs/Contributing/Committing-Changes.md#changes-files)
for more information.
- [x] A detailed QA plan exists on the associated ticket (if it isn't
there, work with the product group's QA engineer to add it)
- [X] Manual QA for all new/changed functionality
- For Orbit and Fleet Desktop changes:
- [X] Orbit runs on macOS, Linux and Windows. Check if the orbit
feature/bugfix should only apply to one platform (`runtime.GOOS`).
- [X] Manual QA must be performed in the three main OSs, macOS, Windows
and Linux.
- [X] Auto-update manual QA, from released version of component to new
version (see [tools/tuf/test](../tools/tuf/test/README.md)).
#18925 (Should also fix #17660.)
Tests:
- Ubuntu 22.04.2
- Wayland
- Works with chrome ✅
- Doesn't work with Firefox. ❌
- Xorg
- Works with Chrome. ✅
- Works with Firefox. ✅
- Ubuntu 24.04
- Wayland
- Doesn't work with Chrome. ❌
- Doesn't work with Firefox. ❌
- Xorg (when using Xorg it defaults to `DISPLAY=:1`, and with the
changes in this PR it works):
- Works with Chrome. ✅
- Works with Firefox. ✅
---
How to change between Wayland and Xorg:
- Set `WaylandEnable=false` in `/etc/gdm3/custom.conf` and reboot.
---
How to determine what's running:
```sh
$ loginctl
SESSION UID USER SEAT TTY
2 1000 luk seat0 tty2
c2 1000 luk
$ loginctl show-session 2 -p Type
# will output
Type=wayland
or
Type=x11
```
---
- [X] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
See [Changes
files](https://fleetdm.com/docs/contributing/committing-changes#changes-files)
for more information.
- [X] Added/updated tests
- [X] Manual QA for all new/changed functionality
- For Orbit and Fleet Desktop changes:
- [X] Manual QA must be performed in the three main OSs, macOS, Windows
and Linux.
- [x] Auto-update manual QA, from released version of component to new
version (see [tools/tuf/test](../tools/tuf/test/README.md)).
