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This page describes how to configure Linux to allow realtime processes for a user, or how to use setcap to grant specific permissions for an executable.

CDP Studio includes functionality for easily setting this up as explained in the App Manager documentation.

For cases where this can not be used, the documentation below explains how to set this up manually.

Using setcap

The recommended approach, if the operating system supports it and the user has the correct access rights, is to use setcap to grant permissions to an executable. The typical syntax is

setcap "cap_net_bind_service,cap_net_admin,cap_net_raw,cap_sys_boot,cap_sys_nice,cap_sys_time+ep" "/path/to/app_name"

Take care to only set the minimum amount of required options. For more information about setcap options, see the setcap capabilities man-page.

Editing limits.conf

Instead of setting permissions on the executable using setcap, it is possible to set up permissions for a user by editing /etc/security/limits.conf.

The example is assuming we want to set up a Raspberry Pi. Make sure that the Raspberry Pi is Paired.

• Log into the Raspberry Pi by right-clicking the Paired device in the Configure mode Deploy Configuration Devices table, and open a remote shell as described in Running Scripts and Commands on a Remote Device.
• Edit the file /etc/security/limits.conf using 'nano':

  sudo nano /etc/security/limits.conf

• Using the arrow-keys, move the cursor to the line before

  # End of file

• ... And copy and paste the following text:

  pi      -   rtprio      99
  pi      -   memlock     unlimited
  pi      -   nice       -20

• Press the Ctrl+x keys, and type 'y', then press Enter to exit the 'nano' editor.
• The target must be rebooted for the change to take effect. To reboot the target, type:

  sudo reboot

  This will stop all running processes, power off the target and power it back on.