Got a good tips from OpenBSD.newbies mailing list. How to lock the machine after suspend. Ok, normally, if I didn't xlock my X session and put the machine under suspend mode (eg: close the lid), my session will be restored when the machine wakes. My session is exposed. So here's how to automatically lock the session when the machine goes into suspend mode.
1) Create a suspend file inside /etc/apm.
In my machine, there's no /etc/apm folder. So I need to create it first. Then create a suspend file inside it.
$ doas mkdir /etc/apm
$ doas vi /etc/apm/suspend
----- /etc/apm/suspend starts -----
pkill -USR1 xidle
----- /etc/apm/suspend ends -----
Then I need to make this suspend executable.
$ doas chmod 744 /etc/apm/suspend
2) Get xidle running on start.
I edited my
.xsession file and add this text:
----- ~/.xsession starts -----
----- ~/.xsession ends -----
Then I run the xidle program.
$ xidle &
So basically when I close my machine's lid, suspend will trigger xidle to lock the machine. Nice stuff.