Start a program after the n-th linux boot up

hhanff · 10-28-2008, 06:02 AM

Hello!

I developed a control program for an Imagenex 881A sonar head. As the whole system shall be deployed in the sea and run autonomously I would like to add the following functionality:

After the n-th boot-up of linux (e.g. after 5 boot-ups) not the standard contoll programm shall be started but a slightly modified version. The problem is that this shall only happen after the n-th boot-up.

How can I solve this problem? Cron does not seem to be very helpfull in my eyes. I was thinking of a shell script that saves the amount of boot-ups in a file and reads it after the n-th boot-up. Then after 5 boot-ups the modified version of my control program will be started.

Greetings,

Hendrik

odcheck · 10-28-2008, 06:12 AM

It must be something with lastlog, you're script must check this file and counts via the dates.

pinniped · 10-28-2008, 06:19 AM

Have a quick look at the shutdown/start scripts and see how 'fsck' does it. A file is updated on each shutdown.

hhanff · 10-28-2008, 07:27 AM

Quote:

Originally Posted by pinniped

Have a quick look at the shutdown/start scripts and see how 'fsck' does it. A file is updated on each shutdown.

That's how I did it:

Code:

#! /bin/bash
START_MOD_AT=3
#AMOUNT_OF_BOOTUPS=0
if test -e .ser_config
then
  echo "ser.config exists..."
  read AMOUNT_OF_BOOTUPS < .ser_config
  echo "Nr:" $AMOUNT_OF_BOOTUPS

  if test $AMOUNT_OF_BOOTUPS -eq $START_MOD_AT ; then
    expr $AMOUNT_OF_BOOTUPS + 1 > .ser_config
    read AMOUNT_OF_BOOTUPS < .ser_config
    echo "Nr: "$AMOUNT_OF_BOOTUPS
	echo "Start modified program here!"
  else
    expr $AMOUNT_OF_BOOTUPS + 1 > .ser_config
    read AMOUNT_OF_BOOTUPS < .ser_config
	echo "Nr: "$AMOUNT_OF_BOOTUPS
	echo "Increment 1..."
  fi
  
else
  touch .ser_config
  echo 1 > .ser_config
  echo "... .ser_config created"
fi

pinniped · 10-29-2008, 01:10 AM

Now you just have to modify your script to accept the start and stop arguments, just like every other service script in init.d. On start (link in rcS.d on Debian) you check the value, maybe run the program, and possibly set the value back to 0. On stop (rc0.d) you increment the value - but you have to do this at a time when the filesystem is still mounted r/w. At the moment your script is written so that everything happens at once (always incremented and checked), which is the wrong way to do it.