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Linux/AM4376: After enabling silent console application get terminated or crashed

Dhananjay Patil
Expert 1210 points
Part Number: AM4376


Tool/software: Linux

Hell All,

We used AM4376 with TI Linux SDK.

We successfully silent the u-boot / kernel messages by enabling silent console option in u-boot and defining silent=1.

We successfully login using telnet on board. 

After login when i execute ps -e | grep myapplication we don't get any output.

I repeat same step after some time but get same result. Application was running before enabling silent console.

I run my application as systemd service.It is defined as follow:

[Unit]
Description=Initmyapplication

[Service]
ExecStart=/usr/bin/myapplication &
StandardOutput=tty

Please guide me to solve this issue.

Regards,

Dhananjay Patil

  • 0
    TI__Guru 55345 points

    Hello Dhananjay,

    Does your application tries to print something on the console? If so disable these prints. Please, also remove the StandardOutput=tty from your Initmyapplication.service file and use the systemctl status myapplication.service and journalctl command to check the application's status.

    Best regards,
    Kemal

  • 0 in reply to Kemal R. Shakir
    TI__Guru 55345 points

    Hello Dhananjay,

    Were the prints in your application caused the termination? What did you see in the journalctl and systemctl status myapplication.service logs?

    Best regards,
    Kemal

  • 0 in reply to Kemal R. Shakir
    Expert 1210 points
    Hi Kemal,
    Yes prints in my application causing the termination.
    This prints are debug prints of application.
    Debug prints should be available when I login through telnet port.
    For above requirement what should i define StandardOutput in service?

    I get following output of systemctl status myapplication.service

    Loaded: loaded (/lib/systemd/system/myapplication.service; static; vendor preset: enabled)
    Active: failed (Result: exit-code) since Fri 2019-01-18 18:38:11 IST; 36min ago
    Process: 791 ExecStart=/usr/bin/myapplication & (code=exited, status=209/STDOUT)
    Main PID: 791 (code=exited, status=209/STDOUT)

    Jan 18 18:38:11 SFT systemd[1]: Started Initmyapplication.
    Jan 18 18:38:11 SFT systemd[1]: myapplication.service: Main process exited, code=exited, status=209/STDOUT
    Jan 18 18:38:11 SFT systemd[1]: myapplication.service: Unit entered failed state.
    Jan 18 18:38:11 SFT systemd[1]: myapplication.service: Failed with result 'exit-code'.



    Regards,
    Dhananjay Patil
  • 0 in reply to Dhananjay Patil
    TI__Guru 55345 points

    You can change the StandardOutput=tty to StandardOutput=journal and use journalctl -u myapplication.service command later to check the debug messages of your application.

  • 0 in reply to Kemal R. Shakir
    Expert 1210 points
    Hi Kemal,

    Thank you for your help.
    journalctl -u myapplication.service gives debug messages
    I assume that after mentioning StandardOutput=journal, all debug messages will stored in file.Correct me if i am wrong.
    Could we redirect our STDOUT to telnet so that when we login using telnet it will print debug messages ?

    Regards,
    Dhananjay Patil
  • 0 in reply to Dhananjay Patil
    TI__Guru 55345 points

    Yes. You can run your application with ExecStart=/bin/sh -c '/usr/bin/myapplication 2>&1 >> /etc/issue.net' and these debug messages will appear when you login using telnet.

  • 0 in reply to Kemal R. Shakir
    Expert 1210 points
    Hi Kemal,
    Thanks for your reply.
    I run application with ExecStart=/bin/sh -c '/usr/bin/myapplication 2>&1 >> /etc/issue.net'.
    What should be StandardOutput for above change?
    I remove 'StandardOutput' option from service.
    Following are my observation:
    1. All log are saved in /etc/issue.net
    2.When I reboot the board it display old data

    Application print debug messages by using printf.
    When I kill my application and after sometime run my application( by giving /usr/bin/myapplication &) then i observe my output of printfs(used for debugging) .

    Is it due to i run my application as service?

    Regards,
    Dhananjay Patil
  • 0 in reply to Dhananjay Patil
    TI__Guru 55345 points

    Yes. All the observations you saw are expected. Use this command line instead ExecStart=/bin/sh -c '/usr/bin/myapplication 2>&1 > /etc/issue.net' if you do not want to see the old data.

  • 0 in reply to Kemal R. Shakir
    Expert 1210 points
    Hi kemal ,
    Thanks for quick reply.
    I have following questions.
    Is there any other way i can display my printf without storing the logs to specific file using telnet?We have limited amount of memory.
    How to start application during boot time without running as service ? So that printf output willbe available.

    Regards,
    Dhananjay Patil
  • 0 in reply to Dhananjay Patil
    TI__Guru 55345 points

    Please, close this thread by clicking on "This resolved my issue" button and create a new thread for your new question.