Kernel module providing devctl notifications for jails.
Build devctl_jail.ko with make and load the kernel module as root using kldload ./devctl_jail.ko.
If you want, you can install it by running make install as root.
This kernel module ships with an example devd.conf and syslogd.conf which add some logging functionality.
Install them and restart devd and syslogd:
cp syslogd.conf /usr/local/etc/syslog.d/jail.conf
touch /var/log/jail
systemctl restart syslogd
cp devd.conf /usr/local/etc/devd/jail.conf
service restart devd
This will give you some logging that looks like this:
May 20 20:50:05 blackbox jail[50581]: Jail JID=1 created
May 20 20:50:08 blackbox jail[50592]: Process PID=50591 attached to Jail JID=1
May 20 20:50:54 blackbox jail[50626]: Jail JID=1 removed
If you are writing a jail manager however, you might be interested in getting the notifications yourself.
You can just connect to the SOCK_SEQPACKET socket at /var/run/devd.seqpacket.pipe to receive raw
notifications multiplexed by devd.