Bare with me here as I am rather new to Linux systems.

I have a Phidgets Debian SBC4 running Stretch 9.x without a GUI interface, it's just the tty terminal.

I also have a program.exe that I have written in C# and run with mono. This program takes stdin input using Console.ReadKey() within a loop and then outputting messages via Console.Writeline(). Depending on what you input, the program toggles some LED lights on/off. Nothing fancy. On program start it just turns all lights on so you can visually see the program is running.

I am able to log into my SBC with root and do mono program.exe and everything works perfectly well. I am able to type input into the console/terminal and then get messages back and the LEDs toggle as expected. No Problem. Now I need this to auto start on boot.

My thinking was, on boot, log in automatically as root and then launch the mono program.exe. To do this I followed the advice in;

Automatically Login on Debian 9.2.1 Command Line

And the result was on boot it logs in as root automatically. All good. Now to launch the program.

I have tried using crontab -e and @reboot mono /blahblah/program.exe and this does indeed launch the program but it appears to launch in the background. So I can see the LEDs light up as expected but there is no relation between the tty terminal and the program. Whatever I type into the terminal does not get read by Console.ReadKey(). Likewise, no messages come back to the terminal.

I have also tried creating a service via systemd and using systemctl start/status etc. and this works on reboot but only for a second or two, then it stops. It prints messages to the console as expected so I think this would also allow input from the console.

But when checking systemctl status it shows loaded was success but active "inactive" and code=killed, signal=HUP

After a bunch of Googling I think this is related to my main program loop and Linux basically saying "I can't execute anything else due to this loop so ima kill it".

How can I get this program to run on boot without it being killed? I don't think I can change the code to remove the loop as it is vital to checking what was inputted and then switching the LEDs on/off

I have tried different combinations of settings in the service file under [Unit] and [Service] but nothing seems to help.

Any advice please would be appreciated.

Edit, I moved away from the service approach and tried adding a .sh script to the /etc/profile.d/myscript.sh and then in that script adding;

exec /usr/bin/mono /path/to/my/program.exe

And now when rebooting it logs in as root and runs the program and it works perfectly. Problem is though, now I can't kill the program as CTRL+C does not work. I added a way to exit my program in the C# code by just typing "exit" into the console but soon as the program ends Debian just logs back in as root and re-launches the program again.

I can do CTRL+ALT+F6 to open tty6 but logging in as root just launches the program again so I am unable to edit the program to make any changes should I wish to.

Is there a way to login without running the profile script?

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.