Auto Update Script

As of version 0.912 the ubermix has a network auto update script installed by default - prior versions include it as part of the default simple updates files (see about the default simple updates files on the key). This script offers the capability to apply updates to a any number of devices whenever they connect to the network. The functionality of the auto update script is quite simple and effective, as follows: when a network connection is established, the device retrieves another script file from a web server (any web server will do) and executes it. In that script, you can pull down and install files and updates and apply them to all of your devices. The script makes maintaining devices quite easy, so we would recommend configuring it for installations of any size, even if you don't know for sure that you will use it.

The default auto update script is in the user's home folder and is called ".network-autostart". Linux hides all files that begin with a ".", so you won't see it in any of the file browsing tools. The script doesn't do anything out of the box - it is essentially disabled. To edit it, open a terminal by pressing "ctrl-alt-t" and type "gedit .network-autostart". Your file will look something like the following:

#!/bin/bash
logger -p user.info "Network Autostart Script Starting"
if [ "`/sbin/ifconfig | grep -v lo | grep Link -A1 | grep inet `" ]; then
        logger -p user.info "An interface is up"
#       if [ -z `pgrep pidgin` ]; then
#               logger -p user.info "Loading Pidgin"
#               pidgin &
#       fi
#       sudo wget http://mirror.saugus.k12.ca.us/une1104/update.sh -O /root/update.sh
#       sudo chmod +x /root/update.sh
#       sudo /root/update.sh
fi

Note that lines that start with a hash mark (#) are disabled. Toward the top of the file are some examples of starting programs when an interface comes up. Near the end there is a line that begins with "wget", which contains the web address for the script file. Change this address to point to one of your web servers and remove the hash marks from the start of the the "wget" line and the two lines after it. You don't have to actually have a script on your web server to make this change, the script won't do anything if it can't download one.

Save the changes, and your device will be ready to self-update. Below is a sample script to install on the web server (for the devices to download):

#!/bin/bash

# Variables Section
#
# Set the WEBSERVER to the url location of the we server storing your updates.
# DO NOT use a trailing slash

WEBSERVER="http://webserver.yourdistrict.k12.ca.us/ubermix-updates"
REBOOT=false

# Functions Section
#
# Contains functions used by the script to handle updates. Do not delete.

standardInstall()
{
  # Performs a standard download and install of a file. Extracts any .tar.gz
  # file, making the assumption that the archive was prepared to be installed
  # from the root (/). Automatically installs any .deb using dpkg.
  # All files to download must have an accompanying md5 checksum file with
  # the same name+.md5 on the web server. To create this file, simply change
  # to the file's directory on the web server and do:
  #
  #	md5sum [filename] >[filename.md5]
  #
  # Function expects either 2 or 3 parameters in the following order:
  # 	1. name of file
  #	2. name of checkfile
  #	3. (optional) destination directory
  #
  # There can be no spaces in any parameter that are not escaped with a \
  # The purpose of the checkfile is to simply create a file in /root/ that
  # is used as a flag to indicate that the update has been installed (so that
  # already installed files don't get reinstalled every time. 
  #
  # Function returns 0 on successful install, 1 for errors or already installed

  FILE=$1
  CKFILE=$2
  RESULT=0
  DESTDIR="/root/"
  if [ -n $3 ]; then
  	if [ -d $3 ]; then
		DESTDIR=$3
	fi
  fi
  if [ ! -e "/root/.$CKFILE" ]; then
	wget "$WEBSERVER/$FILE" -O "$DESTDIR/$FILE"
	wget "$WEBSERVER/$FILE.md5" -O "/root/$FILE.md5"
	if [ -s "$DESTDIR/$FILE" ]; then
		if [ "$(md5sum $DESTDIR/$FILE | cut -d\  -f1)" = "$(cat /root/$FILE.md5 | cut -d\  -f1)" ]; then
			if `echo $1 | grep -q tar.gz`; then
				tar -xzvf $DESTDIR/$FILE -C / >>/tmp/update.log
				rm -f $DESTDIR/$FILE
			fi
			if `echo $1 | grep -q tgz`; then
				tar -xzvf $DESTDIR/$FILE -C / >>/tmp/update.log
				rm -f $DESTDIR/$FILE
			fi
			if `echo $1 | grep -q .deb`; then
				dpkg -i $DESTDIR/$FILE  >>/tmp/update.log
			fi
			touch /root/.$CKFILE
			echo "$CKFILE update applied" >>/tmp/update.log
			rm -f /root/$FILE.md5
	  	else
	    		RESULT=1
	  	fi
	else
	  RESULT=1
	fi
  else
  	RESULT=1
  fi
  return $RESULT
}


# Main Updates Section.
#
# Add your updates here. See notes for standardInstall function above for
# details on how to use it


#Example
#standardInstall showid.tar.gz showid_update



if $REBOOT; then 
	xmessage "An important update has occured. Your netbook is restarting." & >>/tmp/update.log
	sleep 5
	reboot
fi

This script automates much of the update process. Read the comments in the script for details.