Scripts launched from udev do not have DISPLAY access anymore?

user_754174 0
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I have a script that runs from udev when I plug in my external drive. It always worked. But after upgrading from Linux 3.8/Xorg 1.12/Mint 14 (Ubuntu 12.10 compatible) to Linux 3.11/Xorg 1.14/Mint 16 (Ubuntu 13.10 compatible), it doesn't work anymore.

The script still runs, but none of the commands that require the display work. I figured that out by quitting the udev daemon and manually run udevd --debug for verbose output (more below).

This script used to work in Mint 14/12.10:

export DISPLAY=:0
UUID=$1
DEV=$2

notify-send -t 700 "mounting $DEV ($UUID)"
gnome-terminal -t "Backing up home..." -x rsync long line of data
zenity --warning --text="Done."

But not anymore in Mint 16/13.10. In case you are wondering about possible solutions, I gradually added stuff and now it looks like this:

export DISPLAY=:0.0

xhost +local:
xhost +si:localuser:root
xhost +

DISPLAY=:0.0
export DISPLAY=:0.0
UUID=$1
DEV=$2

notify-send -t 700 "mounting $DEV ($UUID)"
gnome-terminal -t "Backing up home..." -x rsync long line of data
zenity --warning --text="Done." --display=:0.0

But it still doesn't work. udevd --debug still shows this:

'(err) 'No protocol specified'
'(err) ''
'(err) '** (gnome-terminal:24171): WARNING **: Could not open X display'
'(err) 'No protocol specified'
'(err) 'Failed to parse arguments: Cannot open display: '
'(err) 'No protocol specified'
'(err) ''
'(err) '** (zenity:24173): WARNING **: Could not open X display'
'(err) 'No protocol specified'
'(err) ''
'(err) '(zenity:24173): Gtk-WARNING **: cannot open display: :0.0'
'(err) 'No protocol specified'

Note that any bash logic works. Echoing test vars to >>/tmp/test.log works. It's just accessing the display that does not work anymore.

This is driving me crazy. What is the correct way to achieve this now?

Update 2013-12-20

So, in the previous Ubuntu, X commands would automatically find it's way to the current X using user.

Now, I seem to need these two things every time:

  • On the X using user:
    • xhost +si:localuser:root
  • On the root/udev side:
    • Copy X using users' ~/.Xauthority file to /root

This 'feels' like a step back in time. This only works scripted when I log in as the same user everytime, so I can copy the .Xauthority file from that users' home when the script executes.

What 'trick' did the old Ubuntu use to have this done auto'magic'ally?

linux-mint udev xorg ubuntu linux
6 Answers

I had to use this in Kali Linux 2016 to get it to work:

#!/bin/bash
set -x
xhost local:root
export DISPLAY=:0.0
su root -c 'zenity --notification --text="I am a notification!"'
user_3785060

If calling the script directly from udev doesn't work, why not start a systemd service which calls that script?

Here's my solution:

First is the udev rule that runs media-storage-unplugged.service when a device (or partition) that has ID_PART_ENTRY_UUID is unplugged

/etc/udev/rules.d/storage-unplugged.rules:

ACTION=="remove", KERNEL=="sd[a-z][0-9]", ENV{ID_PART_ENTRY_UUID}=="replace-with-your-uuid", SYMLINK+="storage", RUN+="/usr/bin/systemctl --no-block start media-storage-unplugged.service"

/etc/systemd/system/media-storage-unplugged.service: (service file)

[Unit]
Description=Triggered when storage is unplugged

[Service]
Type=oneshot
ExecStart=/usr/local/bin/storage_unplugged

[Install]
WantedBy=multi-user.target

/usr/local/bin/storage_unplugged (get creative here)

#!/bin/bash
notify-send-to-user "storage unplugged"
exit 0

/usr/local/bin/notify-send-to-user

#!/bin/bash

function ns() {
    #Detect the name of the display in use
    local display=":$(ls /tmp/.X11-unix/* | sed 's#/tmp/.X11-unix/X##' | head -n 1)"

    #Detect the user using such display (NOTE: Didn't work on Arch linux since the "who" command doesn't show which display the user is using)
    #local user=$(who | grep '('$display')' | awk '{print $1}' | head -n 1)
    #Statically assign user:
    local user="user" # Replace with your user

    #Detect the id of the user
    local uid=$(id -u $user)

    sudo -u $user DISPLAY=$display DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$uid/bus notify-send "$@"
}

ns "$@"

Adapt this method to your needs :)

user_134801650
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