Workaround for broken network tray applet

I'll post about this problem here, and solution, as it eluded me for some days. It has also hit other users of EasyOS in the past...

What happens is you bootup, there is an ethernet or wifi connection to the Internet, that you see in a notify window that pops up at top-right of screen. Yet, the network tray icon remains showing disconnected.

That's the problem. What happens is the binary-executable daemon /usr/local/pup_event/pup_event_frontend_d is started by /root/.xinitrd when Xorg has started, and that daemon waits for network events, and updates, amount other things, /tmp/pup_event_backend/network_ ...but the daemon misses the network event.

Here is the source code for pup_event_frontend_d:

https://github.com/bkauler/woofq/blob/main/easyos/source/gcc/pup_event_frontend_d.c

...God, did I write that!!! I wrote it in 2019, and it is now like trying to read a foreign language.

Anyway, got the gist of it. The daemon will detect a network is "up" and write the interface, for example "wlan0", to /tmp/pup_event_backend/network_

The network tray applet reads /tmp/pup_event_backend/network_ and will display network connected if there is something in that 'network_' file.

However, sometimes it is empty. This can occur when /usr/bin/NetworkManager, which is started by /etc/init.d/rc.networkmanager (or in the latest Easy Excalibur, /etc/init.d/network-manager) makes a network connection before pup_event_frontend_d has started. So the latter misses out on detecting a network change.

...at least, that's what seems to be happening. Doesn't explain why I never had this problem before (though others have reported it).

The source code for the network-manager-applet can be found here:

http://distro.ibiblio.org/easyos/source/alphabetical/n/

...I'm using this one, with patch, not the .deb one available from the Debian repository.

I was scratching my head for a few days, trying to recall how it all hangs together. Back in 2019-2020, I did have some code to trigger pup_event_frontend_d, let it know that a network status has changed, in case it missed it. But that code is currently not being used...

You can find this not-used code at the bottom of /usr/sbin/delayedrun, and also in /usr/local/pup_event/netchg

Now, conducting an experiment...

I emptied /tmp/pup_event_backend/network_, made it a zero-size file, and yes, the network tray applet immediately showed as disconnected. Then did this in a terminal:

# ip link set lo down
# ip link set lo up

...nup. Tried this:

# echo change > /sys/class/net/wlan0/uevent

No joy either. So, what is happening in pup_event_frontend_d? I thought it would detect those changes. Tried a couple of other things, didn't trigger the daemon either. Hmmm...

OK, will cheat. In the delayedrun script, at the bottom, detect if /tmp/pup_event_backend/network_ is empty, if so, run 'getlocalip' to find out which network interface is connected to the Internet, then just directly write it, say "wlan0", to /tmp/pup_event_backend/network_

...yes, network tray applet now working.

I'll put in that workaround, into /usr/sbin/delayedrun, this:

if [ -e /tmp/pup_event_backend/network_ ];then
 if [ ! -s /tmp/pup_event_backend/network_ ];then
  xIF="$(getlocalip | grep '^[we][lt]' | cut -f 1 -d ':' | head -n 1)"
  if [ -n "${xIF}" ];then
   echo -n "${xIF}" > /tmp/pup_event_backend/network_
  fi
 fi
fi

But really should study that pup_event_frontend_d daemon C code, try and figure out why it isn't triggering.

EDIT:
Proper fix, see next blog post:

https://bkhome.org/news/202507/proper-fix-for-network-tray-applet.html   

Tags: easy