Wayland socket is missing when Systemd enabled

[xuangeyouneihan]

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Describe the issue
When Systemd on my subsystem started working by accident, I found that all my GUI apps can only be opened via X11. Then I found that there was no wayland-0 in /run/user/1000. I do not know why the socket was gone, but it seems to be related to Systemd. Though I wrote a script as an alternative workaround, the problem has not been really solved. Wayland socket exists in Ubuntu WSL with Systemd running, so it does not seem to be an issue of WSL.

To Reproduce
Just try to make Systemd work

Expected behavior
Wayland socket exists, and GUI apps can use it.

Screenshots
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Enviroment:

• Windows build number: 10.0.22631.3296
• Security Software: Windows Defender
• WSL version 1/2: WSL2
• ArchWSL version: 24.3.11.0
• ArchWSL Installer type zip/appx/other clean/update: scoop/zip
• Launcher version: 23072600

Additional context

1. To make Systemd work, first I tried to add something to %USERPROFILE%\.wslconfig according to #356 to disable cgroups v1, but it did not work. Then I found another article and modified .wslconfig according to it, and it worked. I renamed .wslconfig to .wslconfig1 without modifying it to enable cgroups v1, and Systemd was also working somehow. But when I tried to rename .wslconfig1 back without modifying it to disable cgroups v1, backup the origional ext4.vhdx, unregister ArchWSL, and then re-install it with a new ext4.vhdx, Systemd did not work. So I actually have no idea about how to make Systemd work.
2. Eventually, inspired by a post, I wrote a script, which links everything in /mnt/wslg to /run/user/$UID at startup, as an alternative workaround. Copy the content below and paste it to /etc/systemd/system/user-runtime-dir@.service.d/link.conf to "solve" the problem:

   [Service]
   ExecStart = sh -c "ln -fs /mnt/wslg/runtime-dir/* /run/user/"%i
   

[xuangeyouneihan]

@9numbernine9

Does wayland-0 exist in /run/user/$UID with version 22.10.16.0? I found that wayland-0 is missing in version 24.3.11.0 when Systemd accidentally enabled, see [this issue]

No, it doesn't.

So Wayland does not work, right? If it works, what is $XDG_RUNTIME_DIR?

[viruscamp]

The root cause is Arch mounts /tmp and /run/user/1000 as tmpfs after startup, make the existing /tmp/.X11-unit/X0 and /run/user/1000/wayland-0 unavailable.

Disable tmp.mount is one useful solution, but I recommend:

$ cat /etc/tmpfiles.d/wslg.conf
# See tmpfiles.d(5) for details
# link WSLg display files after system started

# Type Path              Mode UID  GID  Age Argument
L+     /tmp/.X11-unix/X0 -    -    -    -   /mnt/wslg/.X11-unix/X0

I have no idea how to disable mounting /run/user/1000 as tmpfs, so I recommend:

$ cat ~/.config/user-tmpfiles.d/wslg.conf
# Type Path              Mode UID  GID  Age Argument
L+     %t/wayland-0      -    -    -    -   /mnt/wslg/runtime-dir/wayland-0
L+     %t/wayland-0.lock -    -    -    -   /mnt/wslg/runtime-dir/wayland-0.lock
L+     %t/pulse/native   -    -    -    -   /mnt/wslg/runtime-dir/pulse/native
L+     %t/pulse/pid      -    -    -    -   /mnt/wslg/runtime-dir/pulse/pid
L+     %t/dbus-1         -    -    -    -   /mnt/wslg/runtime-dir/dbus-1

$ systemctl --user enable systemd-tmpfiles-setup.service systemd-tmpfiles-clean.timer

[xuangeyouneihan]

The root cause is Arch mounts /tmp and /run/user/1000 as tmpfs after startup, make the existing /tmp/.X11-unit/X0 and /run/user/1000/wayland-0 unavailable.

Disable tmp.mount is one useful solution, but I recommend:

$ cat /etc/tmpfiles.d/wslg.conf
# See tmpfiles.d(5) for details
# link WSLg display files after system started

# Type Path              Mode UID  GID  Age Argument
L+     /tmp/.X11-unix/X0 -    -    -    -   /mnt/wslg/.X11-unix/X0

I have no idea how to disable mounting /run/user/1000 as tmpfs, so I recommend:

$ cat ~/.config/user-tmpfiles.d/wslg.conf
# Type Path              Mode UID  GID  Age Argument
L+     %t/wayland-0      -    -    -    -   /mnt/wslg/runtime-dir/wayland-0
L+     %t/wayland-0.lock -    -    -    -   /mnt/wslg/runtime-dir/wayland-0.lock
L+     %t/pulse/native   -    -    -    -   /mnt/wslg/runtime-dir/pulse/native
L+     %t/pulse/pid      -    -    -    -   /mnt/wslg/runtime-dir/pulse/pid
L+     %t/dbus-1         -    -    -    -   /mnt/wslg/runtime-dir/dbus-1

$ systemctl --user enable systemd-tmpfiles-setup.service systemd-tmpfiles-clean.timer

Does %t refer to $XDG_RUNTIME_DIR? Also, I tried to add L+ /run/user/1000/wayland-0 - - - - /mnt/wslg/runtime-dir/wayland-0 to /etc/tmpfiles.d/wslg.conf, but it did not work, why?

Add: I added the content that links files in /mnt/wslg/runtime-dir to /etc/tmpfile.d/wslg.conf, but it did not work. Must I add the content to ~/.config/user-tmpfile.d/wslg.conf? If so, I think my workaround might be better, since it works globally, not just for one user.

[viruscamp]

1. system-tmpfiles.d and user-tmpfiles.d are different services, you cannot write conf in one file

• /usr/lib/systemd/system/systemd-tmpfiles-setup.service
• /usr/lib/systemd/user/systemd-tmpfiles-setup.service

2. Writing /run/user/1000/wayland-0 to /etc/tmpfiles.d/ is useless

• file owner and group are wrong
• /run/user/1000/ will be remounted as tmpfs later, clear the file

3. The only global conf location for user-tmpfiles.d is /usr/share/user-tmpfiles.d/*.conf
   but user systemd-tmpfiles-setup is not enabled by default in arch, you have to enable it for each user.

4. this user service may work globally for each user(incomplete and untested):

$ cat /etc/systemd/user/wslg-user-runtime-dir.service
[Service]
ExecStart = sh -c "ln -fs /mnt/wslg/runtime-dir/* "%t

[xuangeyouneihan]

1. system-tmpfiles.d and user-tmpfiles.d are different services, you cannot write conf in one file

   • /usr/lib/systemd/system/systemd-tmpfiles-setup.service

   • /usr/lib/systemd/user/systemd-tmpfiles-setup.service

   2. Writing /run/user/1000/wayland-0 to /etc/tmpfiles.d/ is useless

   • file owner and group are wrong

   • /run/user/1000/ will be remounted as tmpfs later, clear the file

   3. The only global conf location for user-tmpfiles.d is /usr/share/user-tmpfiles.d/*.conf
      but user systemd-tmpfiles-setup is not enabled by default in arch, you have to enable it for each user.

   4. this user service may work globally for each user(incomplete and untested):

$ cat /etc/systemd/user/wslg-user-runtime-dir.service
[Service]
ExecStart = sh -c "ln -fs /mnt/wslg/runtime-dir/* /run/user/"%i

Well, I think 4 should work, because my link.conf is completely same with your wslg-user-runtime-dir.service, and I'm using it.

[viruscamp]

We'd better use %t as XDG_RUNTIME_DIR

$ cat /etc/systemd/user/wslg-user-runtime-dir.service
[Service]
ExecStart = sh -c "ln -fs /mnt/wslg/runtime-dir/* "%t

[xuangeyouneihan]

We'd better use %t as XDG_RUNTIME_DIR

$ cat /etc/systemd/user/wslg-user-runtime-dir.service
[Service]
ExecStart = sh -c "ln -fs /mnt/wslg/runtime-dir/* "%t

I've tried this, but it did not work in my link.conf. Maybe I need to export "ln -fs /mnt/wslg/runtime-dir/* "%t to a file to find out why it didn't work

[xuangeyouneihan]

We'd better use %t as XDG_RUNTIME_DIR

$ cat /etc/systemd/user/wslg-user-runtime-dir.service
[Service]
ExecStart = sh -c "ln -fs /mnt/wslg/runtime-dir/* "%t

I've tried this, but it did not work in my link.conf. Maybe I need to export "ln -fs /mnt/wslg/runtime-dir/* "%t to a file to find out why it didn't work

Well, I added sh -c "echo "%t" > /home/[username]/aaa.txt" in my link.conf, and found that %t is /run.

As for your systemd-tmpfiles-setup.service, I could not even start it. When I inputed sudo systemctl start /etc/systemd/user/wslg-user-runtime-dir.service in my terminal, it told me "Failed to start etc-systemd-user-wslg\x2duser\x2druntime\x2ddir.service.mount: Unit etc-systemd-user-wslg\x2duser\x2druntime\x2ddir.service.mount not found."; when I typed sudo systemctl start wslg-user-runtime-dir.service, it said "Failed to start wslg-user-runtime-dir.service: Unit wslg-user-runtime-dir.service not found." Please tell me how to start it. Thanks 😂

[viruscamp]

I guess that your /etc/systemd/system/user-runtime-dir@.service.d/link.conf is part of user init process, not a standalone user service.

User's XDG_RUNTIME_DIR is not done , when sh -c "ln -fs /mnt/wslg/runtime-dir/* "%t executed.

[xuangeyouneihan]

Maybe. BTW, do you know how to start your wslg-user-runtime-dir.service?

[viruscamp]

$ cat /etc/systemd/user/wslg-runtime-dir.service
[Service]
Type=oneshot
ExecStart=sh -c "ln -fs /mnt/wslg/runtime-dir/* "%t

[Install]
WantedBy=default.target

$ sudo systemctl --global enable wslg-runtime-dir
Created symlink /etc/systemd/user/default.target.wants/wslg-runtime-dir.service → /etc/systemd/user/wslg-runtime-dir.service.

[xuangeyouneihan]

It works! Thank you so much!