Prevent Ubuntu from shutdown before background automatic updates complete

Molly-Guard is a program for exactly this purpose; it requires you do a small amount of setup, and have /usr/sbin before /sbin in your $PATH.

Otherwise, according to this the exact details are highly dependent on the GUI / DE's implementation. Since we know your friend is using Xubuntu, this narrows it, but without recompiling Xfce with this support built-in (which would create further issues) it seems very hard.

According to my bountiful research, you can theoretically just replace /sbin/shutdown with a script that checks if an apt job is up and executes sudo shutdown -c or sudo init 2 to cancel a running shutdown and wait for it to exit, but I'm not sure how robust this is.

According to this, you could just make it hard for the user to shutdown, instead of hooking a script.

Finally, as outlined here, you could install unattended-upgrades over whatever system you're using for autoupdates now, and make sure it exits before shutdown as detailed in this answer.

There are many options, all of which are varying levels of unreliable, but I think the best one, which solves what I think is, to some extent, an underlying X / Y Problem at play here, is this:

Use `crontab` to make his computer run `dpkg --configure -a` on every boot.

@LovesTha: For your purpose, I recommend unattended-upgrades, or perhaps Molly-Guard.

Introduction

The script bellow uses interrupt-driven polling for specific messages from dbus, and whenever it sees request for shutdown/reboot , it will test whether or not a package manager such as dpkg or apt are running. If they are running, the shutdown request will be cancelled.

Set up

Since you have mentioned that your friend doesn't want to touch command line, you will either need to ssh into his machine, or come over and install this manually.

Manual setup

mkdir $HOME/bin
Copy the script source, save into file named preventShutdown.sh
The script must be executable. Use chmod +x $HOME/bin/preventShutdown.sh to do that
Add a script to list of routines to be ran on login to Unity/Gnome using Startup Applications app or by manually placing a .desktop file into $HOME/.config/autostart

Alternative Setup

sudo apt-get install git
cd /opt
sudo git clone https://github.com/SergKolo/sergrep.git
sudo chmod +x /opt/sergrep/*

Add the script as a startup application.

Script Source

#! /bin/bash

##########################
# AUTHOR: Serg Kolo 
# Date: Saturday, December 26th, 2015
# Description: Script to notify user and prevent 
#   shutdown or reboot
#   if any update or package manager
#   are running. 
# TESTED ON: 14.04.3 LTS, Trusty Tahr
# WRITTEN FOR: http://askubuntu.com/q/702156/295286
# VERSION: 2, removed xdotool, using dbus method
#          changed to C-style of organizing code
#########################

# Copyright (c) 2015 Serg Kolo
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal in 
# the Software without restriction, including without limitation the rights to use,
# copy, modify, merge, publish, distribute, sublicense, and/or sell copies of 
# the Software, and to permit persons to whom the Software is furnished to do so, 
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all 
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

# Uncomment the line bellow if needed for debugging
# set -x
###########################
# VARIABLES
###########################

DISPLAY=:0 # has to be set since we are using notify-send


###########################
# MAIN
###########################
#
#    Basic idea : This runs dbus-monitor which waits for
# "RebootRequested" memberf from com.canonical.Unity.Session ,
# which apprears only when the user clicks the shutdown option 
# from the Unity's top right drop down box. Why RebootRequested ?
# Because this message is guaranteed to pop up once user presses
# the shutdown button.
#   The while loop with read command does the big job.
# dbus-monitor sends initial message , so we want to filter only
# The output that contains the string we need, hence the case...esac
# structure employed here. Once we get the proper message.
# we check whether update-manager or package managers are running
# If there is one instance, then call CancelAction method
# and send notification to the user.
#   Both dbus-monitor and while loop run continuously. This
# can be launcher as script in `/etc/rc.local` or `/etc/rc2.d`
# or preferably (!) in `/etc/xdg/autostart/` . 
#   Here is sample /etc/xdg/autostart/preventShutdown.desktop file
# 
# [Desktop Entry]
# Type=Application
# Name=Prevent-Update
# Exec=/home/$USER/bin/preventShutdown.sh
# OnlyShowIn=GNOME;Unity;
# Terminal=false
# 
# Remember to make this file  as well as script be root-owned with 
# chmod +x /path/to/Script.
# It is preferred to store the script in user's personal $HOME/bin
# folder.
# Make sure to edit $HOME/.profile file to include that into $PATH
# variable

interupt()
{
 qdbus com.canonical.Unity /com/canonical/Unity/Session com.canonical.Unity.Session.CancelAction
 notify-send "<<< UPDATE IN PROGRESS; DO NOT SHUT DOWN>>>"
 wall <<< "<<< UPDATE IN PROGRESS; DO NOT SHUT DOWN>>>"
}

main()
{
 dbus-monitor --profile "interface='com.canonical.Unity.Session',type=signal" |
 while read -r line;
 do
  case "$line" in
   *RebootRequested*)
       pgrep update-manager || pgrep apt-get || pgrep dpkg
    if [ $? -eq 0 ]; then
           interupt
        fi
     ;;
   esac
 done
}

main

To quote Einstein:
```
Only two things are infinite, the universe and human stupidity, 
and I'm not sure about the former.
```
so there is no 100% warranty against human stupidity, but you can make it harder for not-Einsteins to break things by:
Activating automatic updates on shut down.
Explain that computers are not hammers, nor nails but fragile, intelligent pieces of equipment that need two kinds of food: electricity and updates.

Alternatively,

Stop automatic updates altogether and start by visiting your friend more often and install the updates for him/her yourself.
Ask for beers or a nice meal to "tune" the computer

_{Alternatively:}
_{• use Remmina to keep stuff running smoothly}

Prevent Ubuntu from shutdown before background automatic updates complete

Use `crontab` to make his computer run `dpkg --configure -a` on every boot.

Introduction

Set up

Manual setup

Alternative Setup

Script Source

Alternatively,

Tags:

Shutdown

Upgrade

Dpkg

Apt

Package Management

Related

Recent Posts

Prevent Ubuntu from shutdown before background automatic updates complete

Use crontab to make his computer run dpkg --configure -a on every boot.

Introduction

Set up

Manual setup

Alternative Setup

Script Source

Alternatively,

Tags:

Shutdown

Upgrade

Dpkg

Apt

Package Management

Related

Use `crontab` to make his computer run `dpkg --configure -a` on every boot.