Re: Boot normally, but give me a root shell

[Richard W.M. Jones]

On Fri, Oct 07, 2016 at 09:19:55AM +0200, Ahmad Samir wrote:
> On 6 October 2016 at 23:55, Richard W.M. Jones  wrote:
> > Is there a way to get Fedora to boot into a root shell, without
> > requiring a password?
> >
> > NOTE: I'm not interested in "emergency" shells and this is not for
> > recovering a system.
> >
> > I want the (specialized, non-networked) system to boot as normal, all
> > the way to multi-user.target, and then drop me to a root shell.
> >
> > Rich.
>
> This seems to work with multi-user.target set as the default target:
> # cd /etc/systemd/system/
> # cp /usr/lib/systemd/system/getty@.service [e-mail]
> # sed -i -e 's!ExecStart=-/sbin/agetty!ExecStart=-/sbin/agetty
> --autologin root!' [e-mail]
> # systemctl enable --force [e-mail]

Thanks.

I came up with a slightly different answer, which also works.  I'm
just documenting it here for reference.

I copied debug-shell.service from systemd to
/etc/systemd/system/root-shell.service.  I modified the file as below
because I wanted to start a root shell on /dev/console, and I also
wanted the target to be multi-user.target.

I then enabled the service as usual:

# systemctl enable root-shell

On boot, it starts a root shell with no login required.

Rich.

----------------------------------------------------------------------
#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

[Unit]
Description=Root shell
Documentation=man:sushell(8)
DefaultDependencies=no
IgnoreOnIsolate=yes

[Service]
Environment=TERM=linux
ExecStart=/sbin/sushell
Restart=always
RestartSec=0
StandardInput=tty
TTYPath=/dev/console
TTYReset=yes
TTYVHangup=yes
KillMode=process
IgnoreSIGPIPE=no
# bash ignores SIGTERM
KillSignal=SIGHUP

# Unset locale for the console getty since the console has problems
# displaying some internationalized messages.
Environment=LANG= LANGUAGE= LC_CTYPE= LC_NUMERIC= LC_TIME= LC_COLLATE= LC_MONETARY= LC_MESSAGES= LC_PAPER= LC_NAME= LC_ADDRESS= LC_TELEPHONE= LC_MEASUREMENT= LC_IDENTIFICATION=

[Install]
WantedBy=multi-user.target