what are the reasons why the wpa_cli command would timeout whilst communicating with the wpa_supplicant control socket in a systemd service?

Question

I'm running the wpa_cli command inside of a python program to check the wifi status. The normal command to check the utility can communicate with the supplicant process is:

/sbin/wpa_cli -iwlext ping

This works fine when I run my program by hand, or test the command above manually.

When I start the process from systemd the command above when run from within the process times-out with

'PING' command timed out.

I'm trying to diagnose why it cannot communicate to the main process via the control socket.

• The process can call the wpa_cli command (I can run and see the output of wpa_cli -v)
• The process can see the iface control socket in /var/run/wpa_supplicant/wlext ( I can run ls -la etc)

Answer 1

The systemd unit for the python process has

PrivateTmp=true

To somewhat segregate processes.

Setting this to false allows the cli to build a client socket in /tmp for the main process socket to link to.