This flag was added in db6aedab92 with the justification that locale
environment variables should be preserved by the user session. However,
the companion patch to drop the UnsetEnvironment= directive blocking
these variables was never merged, so the intended change was never
effected.
While the patch was ineffective toward its stated goal, the "-p" option
does have material negative consequences for the user session in
systemd — environment variables to support the use of
credentials and memory pressure directives, such as
$CREDENTIALS_DIRECTORY and $MEMORY_PRESSURE_WATCH, which are now
directly used by agetty and login, get leaked into the user session
potentially breaking applications that rely on these values.
E.g. systemd-ask-password fails from the tty when $CREDENTIALS_DIRECTORY
has been leaked from agetty, because it expects to be able to access
credentials in $CREDENTIALS_DIRECTORY.
This effectively reverts db6aedab92.
References: db6aedab92 (units: Tell login to preserve environment (#6023), 2017-05-24)
Let's always rely on our own TTY reset logic and tty disallocation/clear
screen logic, thus always pass --noclear and --noreset.
Also, bring the list of baud rates to try into sync for console-getty
and serial-getty (the former might or might not be connected to rs232,
we can't know, hence assume the worst, and copy what
serial-getty@.service does)
In it's latest release, agetty will support reading the agetty.autologin
and login.noauth credentials, so let's make sure we import those in our
getty units so they're available to agetty to read.
If the tty arg is set to "-", agetty uses the stdin fd as the tty.
Let's pass the tty this way so that we keep an fd open to the tty
at all times. If all fd's to a tty are closed, the kernel might
reset the tty which we want to avoid.
We don't need two (and half) templating systems anymore, yay!
I'm keeping the changes minimal, to make the diff manageable. Some enhancements
due to a better templating system might be possible in the future.
For handling of '## ' — see the next commit.
