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shellinfinite-loopopenwrt

Init infinite loop on bootup (shell/Openwrt)

I've been trying to generate and infinite loop in OpenWRT, and I've succeeded:

#!/bin/sh /etc/rc.common
while [ true ] 
do  
    # Code to run
    sleep 15
done

This code works as a charm if I execute it as ./script. However, I want this to start on its own when I turn on my router. I've placed the script in /etc/init.dand enabled it with chmod +x script.

Regardless, the program doesn't start running at all. My guess is that I shouldn't execute this script on boot up but have a script that calls this other script. I haven't been able to work this out.

Any help would be appreciated.

Solution

  • As I have messed with init scripts of OpenWRT in my previous projects. I would like contribute to Rich Alloway's answer (for the ones who will likely to drop here from google search). His answer only covers for "traditional SysV style init scripts" as it is mentioned in the page that he gave link Init Scripts.

    There is new process management daemon, Procd that you might find in your OpenWRT version. Sadly documentation of it has not been completed yet; Procd Init Scripts.

    There are minor differences like they have pointed out in their documentation :

    • procd expects services to run in the foreground,
    • Different shebang,
    • line: #!/bin/sh /etc/rc.common Explicitly use procd USE_PROCD=1
    • start_service() instead of start()

    A simple init script for procd would look like :

    #!/bin/sh /etc/rc.common

# it is run order of your script, make it high to not mess up with other init scripts
START=100 

USE_PROCD=1

start_service() {
  procd_open_instance
  procd_set_param command /target/to/your/useless/command -some -useless -shit -here 
}

    I have posted some blog post about it while ago that might help.