Allow reboot loops initiated using systemd to be - user - interrupted

[Sylvain Pineau]

Reboot stress tests on snappy systems are using a systemd user unit to trigger the plainbox session auto resume.

Similar to a server session, on snappy there's no user session started when plainbox resumes itself hence no way to interact with the tester to interrupt the stress iterations.

It would be nice to have a fsck-like prompt/countdown to allow the user to break the loop.

Such prompt could be managed by plainbox session assistant restart method.

The service unit will have to open a different tty, for example tty2:

[Unit]
Description=Plainbox interactive
<email address hidden>
X-Snappy=yes

[Service]
Type=oneshot
User=admin
ExecStart=/bin/bash -c 'chvt 2; echo -n "How old are you? "; read'
StandardInput=tty
TTYPath=/dev/tty2
TTYReset=yes
TTYVHangup=yes

[Install]
WantedBy=multi-user.target