[systemd-devel] nsapwned container terminal background color

[arnaud gaboury]

On Mon, Mar 20, 2017 at 5:12 AM Zbigniew Jędrzejewski-Szmek <
zbyszek at in.waw.pl> wrote:

> On Sun, Mar 19, 2017 at 09:30:05PM +0000, Zbigniew Jędrzejewski-Szmek
> wrote:
> > On Sun, Mar 19, 2017 at 04:37:53PM +0000, arnaud gaboury wrote:
> > > I am trying with no success to have one background terminal color for
> the
> > > host and another one for the container.
> > >
> > > Some settings:
> > > - on host:
> > > window manager : i3
> > > terminal : urxvt-256
> > >
> > > -on container:
> > > no X, it is a server.
> > >
> > > Until now, I have tried to write a wrapper script to urxvt on host.
> This
> > > script is to test value of $HOST or $TERM, then fire urxvt with
> background
> > > color as option. This does not work.
> > >
> > > I have to figure out  that when i log my container, I am first on an
> urxvt
> > > terminal which become, once I am logged as user on container, a xterm.
> > > I am totally lost where to write instruction as the terminal color
> > > background: on host or container? and what app shall be tested to set
> the
> > > environment and decide the bg color (agetty?) ?
> >
> > Are you starting the container manually using systemd-nspawn in a
> terminal
> > emulator window?


Not really. The container is started at machine boot with
systemd-nspawn at container.service. Then, in one urxvt terminal, I log into
the container with :
# machinectl login container

I have not yet tested your solution, but will do it today and come back
wtih the result.

Thank you


> If yes, then the following works (tested with gnome-terminal,
> > but I think urxvt supports the same sequences):
> >
> > [Unit]
> > DefaultDependencies=no
> > Conflicts=shutdown.target
> >
> > [Service]
> > StandardOutput=tty
> > ExecStart=/usr/bin/printf '\033]11;darkgreen\007'
> > ExecStop=/usr/bin/printf '\033]11;black\007'
> > Type=oneshot
> > RemainAfterExit=true
> >
> > [Install]
> > WantedBy=basic.target
> >
> > (It would be nicer to undo the setting and return to whatever the old
> > background was, but I don't know how to do this.)
> I figured it out, although it's a bit ugly ;)
>
> ==> /etc/systemd/system/bgcolor.service <==
> [Unit]
> DefaultDependencies=no
> Conflicts=shutdown.target
> Description=Set terminal background
>
> [Service]
> StandardInput=tty
> StandardOutput=tty
> ExecStart=/usr/local/bin/bgcolor.sh start /run/bgcolor.txt teal
> ExecStop=/usr/local/bin/bgcolor.sh stop /run/bgcolor.txt
> Type=oneshot
> RemainAfterExit=true
>
> [Install]
> WantedBy=sysinit.target
>
> ==> /usr/local/bin/bgcolor.sh <==
> #!/bin/sh -e
>
> file="$2"
> field=11      # background
>
> if [ "$1" == "start" ]; then
>     color="$3"
>
>     oldstty=$(stty -g)
>     stty raw -echo min 0
>     #          OSC   Ps  ;Pt ST
>     printf "\033]${field};?\033\\"
>     IFS=';' read -t1 -r -d '\' answer
>     echo "$answer" | sed 's/^.*\;//;s/[^rgb:0-9a-f/]//g' >"$file"
>     stty "$oldstty"
>
>     printf "\033]${field};${color}\007"
> elif [ "$1" == "stop" ]; then
>     color=$(cat "$file")
>     printf "\033]${field};${color}\007"
> fi
>
> This will set the background to teal during early boot, storing the
> original color in the specified file, and reset it back during
> shutdown. It seems to interfere with the systemd console output
> (newlines get messed up), and sometimes the restoration does not
> work. I suspect that both issues are caused by interference of
> systemd printing to the console concurrently with the script. Most
> likely putting a verify&retry loop around the query for original
> color would fix the second issue.
>
> Zbyszek
>
>
>
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