Bug#836580: systemd: systemctl status pipes through less with escape sequences not applied

[Josh Triplett]

On Mon, Sep 26, 2016 at 10:27:40PM +0200, Martin Steigerwald wrote:
> Am Montag, 26. September 2016, 13:08:07 CEST schrieb Josh Triplett:
> > On Mon, Sep 26, 2016 at 12:10:34PM +0200, Martin Steigerwald wrote:
> > > Am Sonntag, 4. September 2016, 14:47:50 CEST schrieb Josh Triplett:
> > > > On Sun, 04 Sep 2016 10:59:07 +0200 Martin Steigerwald
> > > > <Martin at Lichtvoll.de>
> > > 
> > > wrote:
> > > > > Package: systemd
> > > > > Version: 231-5
> > > > > Severity: minor
> > > > > 
> > > > > Dear Martin, dear Michael, dear Systemd maintainers,
> > > > > 
> > > > > systemctl status for a long time just printed the status directly onto
> > > > > the
> > > > > terminal (Konsole in my case). But since also quite a while it uses
> > > > > less
> > > > > on
> > > > > my system, even tough the output is not larger than one page.
> > > > > 
> > > > > Also the color escape sequences are not executed by less, leavinge me
> > > > > with
> > > > > something like:
> > > > > 
> > > > > ^[[0;1;32m●^[[0m atopacct.service - Atop process accounting daemon
> > > > > 
> > > > >    Loaded: loaded (/lib/systemd/system/atopacct.service; enabled;
> > > > >    vendor
> > > > >    preset: enabled) Active: ^[[0;1;32mactive (running)^[[0m since So
> > > > >    2016-09-04 10:48:07 CEST; 1s ago>
> > > > >    
> > > > >      Docs: man:atopacctd(8)
> > > > >   
> > > > >   Process: 5032 ExecStart=/usr/sbin/atopacctd (code=exited,
> > > > >   status=0/SUCCESS)
> > > > >  
> > > > >  Main PID: 5034 (atopacctd)
> > > > >  
> > > > >     Tasks: 1 (limit: 4915)
> > > > >    
> > > > >    CGroup: /system.slice/atopacct.service
> > > > >    
> > > > >            └─5034 /usr/sbin/atopacctd
> > > > > 
> > > > > Sep 04 10:48:07 merkaba systemd[1]: Starting Atop process accounting
> > > > > daemon... Sep 04 10:48:07 merkaba systemd[1]: atopacct.service: PID
> > > > > file
> > > > > /run/atopacctd.pid not readable (yet?) after start: No such file or
> > > > > directory Sep 04 10:48:07 merkaba atopacctd[5034]: Version: 2.2-3 -
> > > > > 2015/06/25 11:07:21 […] Sep 04 10:48:07 merkaba systemd[1]: Started
> > > > > Atop process accounting daemon. Sep 04 10:48:07 merkaba
> > > > > atopacctd[5034]:
> > > > > ^[[0;1;39mreactivate process accounting^[[0m
> > > > 
> > > > Works fine here with systemd 231-5: "systemctl status" uses less, but it
> > > > interprets color escape sequences, and exits if the output fits entirely
> > > > on the screen.  Can you provide your environment (output of "env"), and
> > > > in particular the values of $LESS and $PAGER?  And can you check if this
> > > > occurs in another terminal, such as xterm?
> > > 
> > > Thanks for your answer Josh. I missed it first seems it was sortet more
> > > downwards due to old date:
> > > 
> > > 
> > > merkaba:~> systemctl status
> > > merkaba:~> echo $LESS
> > > 
> > >  -w
> > > 
> > > merkaba:~> echo $PAGER
> > > 
> > > I do not know who has put that "-w" into LESS variable.
> > > 
> > > But removing it doesn´t help:
> > > 
> > > merkaba:~> unset LESS
> > > merkaba:~> systemctl status
> > > ^[[0;1;31m●^[[0m merkaba
> > > 
> > >     State: ^[[0;1;31mdegraded^[[0m
> > >     
> > >      Jobs: 0 queued
> > >    
> > >    Failed: 2 units
> > >    
> > >     Since: So 2016-09-25 00:35:01 CEST; 1 day 11h ago
> > >    
> > >    CGroup: /
> > > 
> > > Same in xterm.
> > > 
> > > merkaba:~> apt-show-versions | egrep "^less|^systemd:" | grep amd64
> > > less:amd64/sid 481-2.1 uptodate
> > > systemd:amd64/sid 231-7 uptodate
> > 
> > What happens if you explicitly export LESS=R ?  Does that help?
> 
> No.
> 
> > Try running the following in your terminal:
> > 
> > /usr/bin/printf '\e[0;1;31mRED\e[0m'
> > 
> > Does the word "RED" show up in red?
> 
> Yes.
> 
> > Also try this:
> > 
> > /usr/bin/printf '\e[2J'
> > 
> > Does that clear your screen?
> 
> Yes.
> 
> Okay, I think I found something:
> 
> martin at merkaba:~> echo $SHELL
> /usr/bin/zsh
> martin at merkaba:~> systemctl status
> 
> ^[[0;1;31m●^[[0m merkaba
>     State: ^[[0;1;31mdegraded^[[0m
>      Jobs: 0 queued
>    Failed: 2 units
> 
> But:
> 
> 
> martin at merkaba:~> bash
> martin at merkaba:~ -> systemctl status
> 
> ● merkaba
>     State: degraded
>      Jobs: 0 queued
>    Failed: 2 units
> 
> The red dot and degraded are in red.
> 
> 
> So seems some interaction with Z-Shell, that leads to broken escape sequences.
> 
> I use zsh 5.2-5.

Ah, interesting.  Perhaps zsh puts the terminal into an unexpected mode
somehow?

Can you run zsh with whatever options cause it to ignore all your shell
configuration and startup files?  Does that fix the problem?

If the *default* configuration of zsh causes this bug, I'd suggest
reassigning this bug to zsh.

- Josh Triplett