Can't echo to console from dracut module

I have a custom dracut module installed as a pre-mount hook (for Fedora 
18).  This shell script needs to echo some messages to the console, but 
I'm having no luck making that happen.  I've tried:
echo foo
echo foo > /dev/console
echo foo > /dev/kmsg
. /lib/dracut-lib.sh
info foo
. /lib/dracut-lib.sh
export DRACUT_QUIET="no"
/bin/plymouth --hide-splash
info foo

At various times, I've tried booting with rd.info=1, but my final solution 
needs to not require that.  All of these things work as expected from the 
emergency_shell (reached by passing rd.break on the cmd-line).  I've 
looked at that function and haven't seen what I'm missing.  I'm starting 
to suspect the shell works because of the special setup in the 
dracut-emergency.service systemd unit, but haven't yet tried retooling 
things so that my hook scripts becomes not much more than a 'systemctl 
start mycustom.service', which in turn minics dracut-emergency.service but 
instead of a user shell, calls another shell script with the bulk of 
what's presenty in my hook script.

Is there a simpler way or anybody know what I'm doing wrong or need to do 
differently?  Given that I'm doing this all in a LiveOS image, my 
turn-around time for testing is rather slow and tedious.
--
John Florian

[Brian C. Lane]

On Fri, Mar 08, 2013 at 02:55:40PM -0500, John.Florian(a)dart.biz wrote:
>  I have a custom dracut module installed as a pre-mount hook (for
> Fedora 
>  18).  This shell script needs to echo some messages to the console, but 
>  I'm having no luck making that happen.  I've tried: 
This is similar to what we ran into with checkisomd5, now that systemctl
is being used by dracut you need to setup a service with access to the
console in order for anything to be output (or input).

The service file for that looks like this:

[Unit]
Description=Media check on %f
DefaultDependencies=no
Before=shutdown.target

[Service]
Type=oneshot
RemainAfterExit=no
ExecStart=/bin/checkisomd5 --verbose %f
StandardInput=tty-force
StandardOutput=inherit
StandardError=inherit
TimeoutSec=0

You can look at commits 040f3883 and 5204d1d3 in dracut to see how it is
setup.

-- 
Brian C. Lane | Anaconda Team | IRC: bcl #anaconda | Port Orchard, WA (PST8PDT)

>  From: "Brian C. Lane" <bcl(a)redhat.com&gt;
>  
>  On Fri, Mar 08, 2013 at 02:55:40PM -0500, John.Florian(a)dart.biz wrote:
>  > I have a custom dracut module installed as a pre-mount hook (for  
Fedora 
>  > 18).  This shell script needs to echo some messages to the
> console,  
but 
>  > I'm having no luck making that happen.  I've tried:
>  
>  This is similar to what we ran into with checkisomd5, now that systemctl
>  is being used by dracut you need to setup a service with access to the
>  console in order for anything to be output (or input).
>  
>  The service file for that looks like this:
>  
>  [Unit]
>  Description=Media check on %f
>  DefaultDependencies=no
>  Before=shutdown.target
>  
>  [Service]
>  Type=oneshot
>  RemainAfterExit=no
>  ExecStart=/bin/checkisomd5 --verbose %f
>  StandardInput=tty-force
>  StandardOutput=inherit
>  StandardError=inherit
>  TimeoutSec=0
>  
>  You can look at commits 040f3883 and 5204d1d3 in dracut to see how it is
>  setup.
>  
>  -- 
>  Brian C. Lane | Anaconda Team | IRC: bcl #anaconda | Port Orchard, 
>  WA (PST8PDT) 

Thanks for that Brian!  I had pretty much came to that conclusion before 
calling it a day on Friday, but it's very helpful to know that the effort 
to go that route won't be wasted.

--
John Florian

>  From: John.Florian(a)dart.biz
>  
>  > From: "Brian C. Lane" <bcl(a)redhat.com&gt; 
>  > 
>  > On Fri, Mar 08, 2013 at 02:55:40PM -0500, John.Florian(a)dart.biz wrote:
>  > > I have a custom dracut module installed as a pre-mount hook (for  
Fedora

>  > > 18).  This shell script needs to echo some messages to the
> console,  
but 
>  > > I'm having no luck making that happen.  I've
> tried:
>  > 
>  > This is similar to what we ran into with checkisomd5, now that  
systemctl
>  > is being used by dracut you need to setup a service with access
> to the
>  > console in order for anything to be output (or input).
>  > 
>  > The service file for that looks like this:
>  > 
>  > [Unit]
>  > Description=Media check on %f
>  > DefaultDependencies=no
>  > Before=shutdown.target
>  > 
>  > [Service]
>  > Type=oneshot
>  > RemainAfterExit=no
>  > ExecStart=/bin/checkisomd5 --verbose %f
>  > StandardInput=tty-force
>  > StandardOutput=inherit
>  > StandardError=inherit
>  > TimeoutSec=0
>  > 
>  > You can look at commits 040f3883 and 5204d1d3 in dracut to see how it  
is
>  > setup.
>  > 
>  > -- 
>  > Brian C. Lane | Anaconda Team | IRC: bcl #anaconda | Port Orchard, 
>  > WA (PST8PDT)
>  
>  
>  Thanks for that Brian!  I had pretty much came to that conclusion 
>  before calling it a day on Friday, but it's very helpful to know 
>  that the effort to go that route won't be wasted. 
>  
>  --
>  John Florian  

I just wanted to drop another note and thank you to mention that I got it 
working.  I had been mimicking how the dracut-emergency.service worked, 
but the media-check service made an even better example by being even more 
trivial.  So, thanks again!


--
John Florian

Fwd: Can't echo to console from dracut module

[Jins Nazir]

---------- Forwarded message ----------
From: "Brian C. Lane" <bcl(a)redhat.com&gt;
Date: Mon, 11 Mar 2013 06:37:41 -0700
Subject: Re: [Fedora-livecd-list] Can't echo to console from dracut module
To: livecd(a)lists.fedoraproject.org

On Fri, Mar 08, 2013 at 02:55:40PM -0500, John.Florian(a)dart.biz wrote:
>  I have a custom dracut module installed as a pre-mount hook (for
> Fedora
>  18).  This shell script needs to echo some messages to the console, but
>  I'm having no luck making that happen.  I've tried: 
This is similar to what we ran into with checkisomd5, now that systemctl
is being used by dracut you need to setup a service with access to the
console in order for anything to be output (or input).

The service file for that looks like this:

[Unit]
Description=Media check on %f
DefaultDependencies=no
Before=shutdown.target

[Service]
Type=oneshot
RemainAfterExit=no
ExecStart=/bin/checkisomd5 --verbose %f
StandardInput=tty-force
StandardOutput=inherit
StandardError=inherit
TimeoutSec=0

You can look at commits 040f3883 and 5204d1d3 in dracut to see how it is
setup.

-- 
Brian C. Lane | Anaconda Team | IRC: bcl #anaconda | Port Orchard, WA (PST8PDT)