CODEWITHSUNDEEP
linuxubuntulinux-device-driverudevhotplugging
Mr OpenCV
Mr OpenCV

Reputation: 51

udev rule doesnt trigger GUI application

I am able to get this udev rule in 99-monitor-hotplug.rules to trigger:

ACTION=="change", SUBSYSTEM=="drm", ENV{HOTPLUG}=="1", 
RUN+="/usr/local/bin/monitor-hotplug.sh"

But I cannot seem to get it to trigger an OpenCV GUI application in the monitor-hotplug.sh script.

I understand fundamentally the udev rule runs as root but no matter what syntax I try I cannot get it to run properly at the user level for running the application (the actual script to run the application works fine).

I have tried in RUN this format: 

su - your_X_user_here -c 'export DISPLAY=:0; bash -c "/path/to/script.sh"'

with script:

#!/bin/bash
#sleep 5
date >> /var/log/opencvlog.log
cd ~/Downloads
./displayimage /home/<username>/Pictures/picture.png 
>/var/log/application.log 
2>&1

Another attempt:

Adding in 99-monitor-hotplug.rules to the current syntax:

ACTION=="change", SUBSYSTEM=="drm", ENV{DISPLAY}=":0", 
ENV{XAUTHORITY}="/home/<username>/.Xauthority" ENV{HOTPLUG}=="1", 
RUN+="/usr/local/bin/monitor-hotplug.sh"

then in the actual script:

export DISPLAY=:0
export XAUTHORITY=/home/<username>/.Xauthority
cd ~/Downloads
date 
./displayimage /home/<username>/Pictures/picture.png

None of this is working, any thoughts on how to get this to work?

Thanks

Upvotes: 1

Views: 852

Answers (1)

Antonio Ospite
Antonio Ospite

Reputation: 171

When using display managers like gdm the current X authority file might not be in the user home directory, but in runtime directories like /run or /var/run.

You may try something like:

USER=<username>
export XAUTHORITY=$(find /var/run/gdm3/ -type f -path "*${USER}*" 2> /dev/null)

Newer gdm versions seem to put the file in a more generic location:

export XAUTHORITY=$(find /run/user/$(id -u "$USER")/ -name Xauthority 2> /dev/null)

I used this technique to call xrandr to adjust the screen resolution from a udev rule:
https://git.ao2.it/libam7xxx.git/blob/HEAD:/contrib/am7xxx-autodisplay.sh

Upvotes: 0

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