Re: [ptxdist] console_name for systemd based systems

[Michael Olbrich <m.olbrich@pengutronix.de>]

Hi,

On Wed, Mar 28, 2012 at 11:09:55AM +0200, Alexander Dahl wrote:
> moving along with systemd integration I came across an issue where I'm
> not sure how to integrate this nicely into ptxdist. Let me explain how
> this works for busysbox init at the moment:
> 
> There's PTXCONF_CONSOLE_NAME in platformconfig. For our project it has
> the value /dev/ttyS0 because the target has no graphics system but just
> a serial console. For busybox this is put to /etc/inittab around line 41
> of rules/initmethod-bbinit.make:
> 
>  40     @$(call install_replace, initmethod-bbinit, /etc/inittab, \
>  41         @CONSOLE@, $(PTXCONF_CONSOLE_NAME))
> 
> The resulting line in /etc/inittab:
> 
>  console::respawn:/sbin/getty -L 115200 /dev/ttyS0 vt100
> 
> Now systemd has no inittab anymore. There are two services for getty:
> 
>  # ls /lib/systemd/system/*tty*
>  /lib/systemd/system/getty@.service  
>  /lib/systemd/system/serial-getty@.service
> 
> The first one is used for /dev/tty*, the second for /dev/ttyS* or any
> other serial console (/dev/ttyUSB0 would be possible as well). These are
> activated by setting a symlink at the appropriate place, a quick 'n
> dirty solution ignoring PTXCONF_CONSOLE_NAME looks like this:
> 
>  255     # FIXME there's $(PTXCONF_CONSOLE_NAME) in platformconfig.
> Would be
>  256     #       nice to get this by some magic
>  257     @$(call install_link, myrootfs, \
>  258         /lib/systemd/system/serial-getty@.service, \
>  259        
> /etc/systemd/system/getty.target.wants/serial-getty@ttyS0.service)
> 
> For integrating this into ptxdist, especially in
> rules/initmethod-systemd.*, there would be some magic needed guessing
> which service to pick based on which device is configured in
> PTXCONF_CONSOLE_NAME. Any ideas on this?

I've never needed that with systemd. By default systemd will add such a
dependency for the tty the kernel uses for it's output. So if you boot with
"console=/dev/ttyS0" in the kernel commandline you should get a getty on
ttyS0.

Michael

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