Access Linux ethercat CoE interface as a normal (not sudo) user

Question

I need to read/write the ethercat CoE interface as a normal (not sudo) user. Is there a command to do this at Linux? Or perhaps a systemd configuration that would work just like how udev rules work for making USB devices accessible for read/write without sudo access?

Thank you.

Answer 1

You can change the capability of the executable that accesses Ethercat port with setcap command.

$ sudo setcap cap_net_raw+ep /path/to/executable

Then, you can run the executable as a normal user.

To register this command for a startup script, such as in Ubuntu, create the following systemd service file. $ sudo vim /etc/systemd/system/setcatp.service

File content should be like as below

[Unit]
Description=Set capabilities on executable that accesses Ethercat port
After=network.target

[Service]
Type=oneshot
ExecStart=/sbin/setcap cap_net_raw+ep /home/ubuntu/agv_ws/build/servo_controller/servo_controller/servo_controller
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

Next, set up the systemd

$ sudo systemctl daemon-reload
$ sudo systemctl enable setcap.service
$ sudo systemctl start setcap.service
$ sudo systemctl status setcap.service