Arch Linux

Mobiusstrip

Member

Registered: 2015-08-15

Posts: 2

X 11 $DISPLAY not set as root

I'm having a few issues setting up my system because the $DISPLAY variable is not set as root:

- I wrote a script to cycle my wallpaper using feh. It works correctly as the logged-in user. I can only force it to work for root by manually setting "DISPLAY=:0".

- I set that script to run as a cronjob on the user level via cronie. However, when it runs, it gives me the same errors I get when I run it as root. To verify this I edited cronie service file ( /usr/lib/systemd/system/cronie.service ) to execute /usr/bin/kill -n -s (where -s logs output to the systemlog). Every time the cron job comes in I get this output:

Aug 15 01:30:01 mobius crond[2936]: pam_unix(crond:session): session opened for user user by (uid=0)
Aug 15 01:30:01 mobius CROND[2937]: (user) CMD (/usr/local/bin/wallpaper)
Aug 15 01:30:01 mobius CROND[2936]: (user) CMDOUT (feh ERROR: Can't open X display. It *is* running, yeah?)
Aug 15 01:30:01 mobius CROND[2936]: pam_unix(crond:session): session closed for user user

- I can't properly set redshift as a systemd service without access to the display. (I tried such a service as a normal user, but it wouldn't launch on startx even with "WantedBy=graphical.target". I prefer running it as a systemd service to having "exec redshift [options]" in my .xinitrc.) I am not sure if this is related to a bad systemd service file or root not having access to $DISPLAY.

I tried the 2nd posted solution in the above link, which didn't work (probably because my Xauthority iis unrelated to Display being unset). The first solution had no effect and I do not understand why. I've read a number of solution threads where the answer is to put "export DISPLAY=:0" in the bashrc -- I consider this hackish and it wouldn't solve some of my problems anyways. Most of the other solutions I found involved downloading a nvidia package -- I am not sure if I need one since I already have the intel graphics drivers, and I wouldn't understand why this solved my problem if it were to.

What is the best solution(s) to my problems? Am I missing some magic setting that makes everything work?

Thanks for any help.

Scimmia

Fellow

Registered: 2012-09-01

Posts: 11,605

Re: X 11 $DISPLAY not set as root

You've obviously read https://wiki.archlinux.org/index.php/Ru … ps_as_root, so what specifically have you tried?

Know that systemd services run in a sanitized environment, so they're a special case.

Last edited by Scimmia (2015-08-15 06:04:30)

Mobiusstrip

Member

Registered: 2015-08-15

Posts: 2

Re: X 11 $DISPLAY not set as root

For what it's worth, my service script for redshift has this line:

Environment="DISPLAY=:0"

Does not redshift from being able to find the display.

Currently I've tried:

- Editing /etc/pam.d/su[-1] per the linked arch page

- Exporting user .Xauthority per linked page. No effect.

- "xhost +" run from both user and root. Not permanent. Cronjobs and services still failed.

- "export DISPLAY=:0" in my bashrc. Hackish. Cronjobs and systemd services still failed.

- Changing systemd script to local user service. ( ~.config/systemd/user). Systemd script works but not on boot.

- Moving cronjob to root account. Did not work. Did not expect it to since it fails as normal user with X server permissions.

- Copying /etc/X11/xinitrc to ~/.xinitrc, restoring defaults

I also tinkered around to make sure I had the right intel drivers (xf68-intel and xf86-intel-graphics) for my machine (HP with an i5 core). I've installed and uninstalled a few different desktop managers but have not lost any X server dependencies. All of my X files are in the correct locations.

I would not be surprised if the best solution is putting something in my .xinitrc. But through all the pages I've found none have suggested anything like this.