Re: [PATCH] detour TTY driver - now ttyprintk

From: Kay Sievers
Date: Wed Aug 25 2010 - 03:40:42 EST


On Wed, Aug 25, 2010 at 01:12, Greg KH <gregkh@xxxxxxx> wrote:
> On Wed, Aug 25, 2010 at 12:22:21AM +0100, Alan Cox wrote:
>> > No, it does cover that. ÂYou should be able to do that with a simple
>> > console redirection to /dev/kmsg ÂWhat happened when you tried to do
>> > that?
>>
>> stty: standard input: Inappropriate ioctl for device
>
> Kay, how does systemd handle the kmsg console redirection?

Systemd does not steal the console, this is done by plymouth, in the
same way blogd can do that. It uses a pty and rewrites the messages.

Systemd does pass syslog to the kernel buffer during early boot. Init
provides /dev/log. With systemd, the started services usually don't
get the console connected, but use syslog anyway or the stdout/err
gets redirected to syslog.

With systemd the console is not too useful because we start everything
in parallel. If all the services would put out stuff there like sysv
did, it would look like a real mess.

Kay
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