Start daemon on bash check script started by launchd

Question

Quick question for you, related to launchd, actually on MacOS (Mojave). I'm using an LLDP daemon (lldpd, available here --> https://lldpd.github.io/)

I would like to remove the plist created by this package (/Library/LaunchDaemons/im.bernat.lldpd.plist), and replace it with another I did :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
     <key>Label</key>
     <string>XXX_LLDP_check</string>
     <key>UserName</key>
     <string>root</string>
     <key>ProgramArguments</key>
     <array>
          <string>/opt/xxx/lldp_check.sh</string>
     </array>
     <key>WatchPaths</key>
     <array>
           <string>/etc/resolv.conf</string>
           <string>/Library/Preferences/SystemConfiguration/NetworkInterfaces.plist</string>
     </array>
</dict>
</plist>

What I do here is I watch /etc/resolv.conf and /Library/Preferences/SystemConfiguration/NetworkInterfaces.plist to be able to start my /opt/xxx/lldp_check.sh script whenever there's a change on network interfaces status.

Then this script will do some checks (DNS resolution, ping, etc), to be sure I'm connected to my corporate network before starting the lldpd daemon.

#!/bin/bash

sleep 5

ethernet_if=`networksetup -listallhardwareports | awk '/Ethernet/{getline;print}' | awk 'NR==1 {print $2}'`
ethernet_status=`ifconfig $ethernet_if | grep status | awk '{print $2}'`

if [ "$ethernet_status" = "active" ]
then
    echo "ETHERNET WIRED LINK IS UP" >> /tmp/test.log

    # some checks here (removed for sharing)
    if ping -c 1 1.1.1.1 &> /dev/null
    then
        echo "ON CORPORTATE NETWORK. STARTING LLDPD" >> /tmp/test.log
        /usr/local/sbin/lldpd &
        echo "LLDP started" >> /tmp/test.log
        # adding a sleep to see if it is started 
        sleep 10
    else
        echo "NOT ON CORPORATE NETWORK" >> /tmp/test.log
        killall lldpd
        echo "LLDP killed" >> /tmp/test.log
    fi
else
    echo "ETHERNET WIRED LINK DOWN" >> /tmp/test.log
    killall lldpd
    echo "LLDP killed" >> /tmp/test.log
fi

Unfortunately, thanks to the "sleep 10", I'm able to see that lldpd is started for 10 seconds, but is then killed when this check script terminated.

I also tried to use "launchctl load /Library/LaunchDaemons/im.bernat.lldpd.plist" but with no success.

I also tried adding a "nohup" before the "/usr/local/sbin/lldpd &" but it does not makes it better. If I start the /opt/xxx/lldp_check.sh manually (with root rights), lldpd is started properly.

Do you have an idea ?

Answer 1

Finally found the solution :

• keep "disown" the started lldpd process in the bash script
• add the "abandonprocessgroup" parameter to "True" on the plist file (AbandonProcessGroup)