[launchd-dev] Loading LaunchAgents for users in postinstall

[Per Olofsson]

When an installer package contains a LaunchAgent we typically try to load it into any current user sessions, to avoid requiring a logout or restart. Through trial and error we've arrived at using launchctl bsexec with chroot in a loop like this:

if [[ "$3" == "/" ]]; then
    # Load agent for all logged in users.
    for pid_uid in $(ps -axo pid,uid,args | grep -i "[l]oginwindow.app" | awk '{print $1 "," $2}'); do
        pid=$(echo $pid_uid | cut -d, -f1)
        uid=$(echo $pid_uid | cut -d, -f2)
        if [[ "$uid" -ne 0 ]]; then
            launchctl bsexec "$pid" chroot -u "$uid" / launchctl unload "$AGENT"
            launchctl bsexec "$pid" chroot -u "$uid" / launchctl load "$AGENT"
        fi
    done
fi

It's not perfect but it got the job done, but it looks like it breaks in the 10.11 betas if SIP is enabled (launchctl exits with code 5). Is there a better/proper/supported way of loading LaunchAgents for users in a background script running as root?

-- 
Per Olofsson, IT-service, University of Gothenburg