Comment 18 for bug 677516

Well, my /usr/share/unattended-upgrades script looks like this now:
...
    # run
    start_time = time.time()
    while True:
 subprocess.call(["/bin/plymouth","message", "--text", "unattended-upgrades were here"])
...

I don't see the message every time I shut down the machine, but it's likely because this line is executed before Plymouth is up. I'll use the lock file test you provided and try again.

I started testing this because I saw similar problem on a machine connected to the internet via proxy which silently refused most connections, including Ubuntu repositories. The machine just kept showing the splash and didn't shut down for a long time. But the lock file should be present in this case, so I blamed Plymouth.

I wonder why non-SUID script didn't work for me in the beginning. I tested in on this and on my plymouth-greeter script, both of them didn't work without SUID.