Automatically launch your application

You've just developed a state of the art application and want it to be launched each time you boot your APF ? Then this small tutorial is for you !

System startup

First, a small remainder: when you start your board, here is how all things are started:

1. U-Boot initializes the processor, vital peripherals and then load Linux image from Flash,
2. U-Boot starts Linux image by passing it some parameters, the bootargs,
3. Linux starts, mounts its rootfs and launches /sbin/init,
4. init process checks its /etc/inittab config file and executes the instructions it contains,
5. this config file generally asks init to launch /etc/init.d/rcS at some point,
6. /etc/init.d/rcS look at all scripts in /etc/init.d/ directory which start with a S, and executes them in ascending order

Adding your own application in the ssystem start process

• creates a shell script in /etc/init.d/:

 # touch /etc/init.d/S99app
 # chmod a+x /etc/init.d/S99app

• edit it

 # vi /etc/init.d/S99app

• put in it the following content (replace /usr/bin/your_app with your application name & path):

#!/bin/sh

# Loading the modules needed by my app:
modprobe xxxxx
 
# Launching my app:
/usr/bin/your_app &          # <-- Don't forget the "&" otherwise other system stuff won't start until you leave your app !!!

exit 0

• save your changes and !! Test it !!

# /etc/init.d/S99app

• That's it ! You can now reboot:

# sync
# reboot

Links

• How to customize your boot Logo