* [QUERY] User-Mode Linux and /dev/tty*
@ 2013-07-16 15:54 Ramkumar Ramachandra
2013-07-16 15:59 ` Richard Weinberger
0 siblings, 1 reply; 6+ messages in thread
From: Ramkumar Ramachandra @ 2013-07-16 15:54 UTC (permalink / raw)
To: LKML; +Cc: Jeff Dike, Richard Weinberger, Al Viro
Hi,
So, I was trying to boot User-Mode Linux with a modern rootfs with
systemd on it, and found that it wouldn't present me a prompt. I dug
further, and found out that getty is not able to open /dev/tty1; I
then tried the console-getty.service (which uses /dev/console), and it
worked. The reason it doesn't work out of the box is that systemd is
not able to figure out whether or not a virtual console subsystem is
present: /dev/tty0 is present for some reason (although I'm not sure
it's a virtual console), and this confuses systemd.
So, my question is: does um Linux have a virtual console subsystem?
If so, then why doesn't it seem to work? If not, why does /dev/tty0
exist?
Thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [QUERY] User-Mode Linux and /dev/tty*
2013-07-16 15:54 [QUERY] User-Mode Linux and /dev/tty* Ramkumar Ramachandra
@ 2013-07-16 15:59 ` Richard Weinberger
2013-07-16 16:03 ` Ramkumar Ramachandra
0 siblings, 1 reply; 6+ messages in thread
From: Richard Weinberger @ 2013-07-16 15:59 UTC (permalink / raw)
To: Ramkumar Ramachandra; +Cc: LKML, Jeff Dike, Al Viro
Hi!
Am 16.07.2013 17:54, schrieb Ramkumar Ramachandra:
> Hi,
>
> So, I was trying to boot User-Mode Linux with a modern rootfs with
> systemd on it, and found that it wouldn't present me a prompt. I dug
> further, and found out that getty is not able to open /dev/tty1; I
> then tried the console-getty.service (which uses /dev/console), and it
> worked. The reason it doesn't work out of the box is that systemd is
> not able to figure out whether or not a virtual console subsystem is
> present: /dev/tty0 is present for some reason (although I'm not sure
> it's a virtual console), and this confuses systemd.
>
> So, my question is: does um Linux have a virtual console subsystem?
> If so, then why doesn't it seem to work? If not, why does /dev/tty0
> exist?
UML does not have CONFIG_VT.
But recent systemd versions can deal with that.
Thanks,
//richard
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [QUERY] User-Mode Linux and /dev/tty*
2013-07-16 15:59 ` Richard Weinberger
@ 2013-07-16 16:03 ` Ramkumar Ramachandra
2013-07-16 16:10 ` Richard Weinberger
0 siblings, 1 reply; 6+ messages in thread
From: Ramkumar Ramachandra @ 2013-07-16 16:03 UTC (permalink / raw)
To: Richard Weinberger; +Cc: LKML, Jeff Dike, Al Viro
Richard Weinberger wrote:
> UML does not have CONFIG_VT.
Not sure what this means.
> But recent systemd versions can deal with that.
Nope, running systemd HEAD. I only recently figured out how to detect
that um Linux is running [1].
[1]: https://github.com/systemd/systemd/commit/7080ea16
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [QUERY] User-Mode Linux and /dev/tty*
2013-07-16 16:03 ` Ramkumar Ramachandra
@ 2013-07-16 16:10 ` Richard Weinberger
2013-07-16 16:26 ` Ramkumar Ramachandra
0 siblings, 1 reply; 6+ messages in thread
From: Richard Weinberger @ 2013-07-16 16:10 UTC (permalink / raw)
To: Ramkumar Ramachandra; +Cc: LKML, Jeff Dike, Al Viro
Am 16.07.2013 18:03, schrieb Ramkumar Ramachandra:
> Richard Weinberger wrote:
>> UML does not have CONFIG_VT.
>
> Not sure what this means.
UML does not have virtual consoles.
>> But recent systemd versions can deal with that.
>
> Nope, running systemd HEAD. I only recently figured out how to detect
> that um Linux is running [1].
>
> [1]: https://github.com/systemd/systemd/commit/7080ea16
>
I'm not running HEAD, but opensuse 12.3 (with systemd) works on UML.
Thanks,
//richard
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [QUERY] User-Mode Linux and /dev/tty*
2013-07-16 16:10 ` Richard Weinberger
@ 2013-07-16 16:26 ` Ramkumar Ramachandra
2013-07-16 16:34 ` Richard Weinberger
0 siblings, 1 reply; 6+ messages in thread
From: Ramkumar Ramachandra @ 2013-07-16 16:26 UTC (permalink / raw)
To: Richard Weinberger; +Cc: LKML, Jeff Dike, Al Viro
Richard Weinberger wrote:
> UML does not have virtual consoles.
Then why do I see this on my UML box?
# ls /dev/tty* | wc -l
113
Why is it creating unusable devices? Is drivers/tty.c responsible for
this? What is it exactly?
> I'm not running HEAD, but opensuse 12.3 (with systemd) works on UML.
Also, what's with all the
xterm_open : run_helper failed, errno = 2
messages? (I installed xterm, but it wasn't very enlightening)
How is drivers/xterm.c supposed to work? And what is mconsole?
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [QUERY] User-Mode Linux and /dev/tty*
2013-07-16 16:26 ` Ramkumar Ramachandra
@ 2013-07-16 16:34 ` Richard Weinberger
0 siblings, 0 replies; 6+ messages in thread
From: Richard Weinberger @ 2013-07-16 16:34 UTC (permalink / raw)
To: Ramkumar Ramachandra; +Cc: LKML, Jeff Dike, Al Viro
Am 16.07.2013 18:26, schrieb Ramkumar Ramachandra:
> Richard Weinberger wrote:
>> UML does not have virtual consoles.
>
> Then why do I see this on my UML box?
>
> # ls /dev/tty* | wc -l
> 113
>
> Why is it creating unusable devices? Is drivers/tty.c responsible for
> this? What is it exactly?
This is not UML specific.
Are you using devtmpfs?
>> I'm not running HEAD, but opensuse 12.3 (with systemd) works on UML.
>
> Also, what's with all the
>
> xterm_open : run_helper failed, errno = 2
2 is ENOENT.
Do you have uml-utils installed?
> messages? (I installed xterm, but it wasn't very enlightening)
> How is drivers/xterm.c supposed to work? And what is mconsole?
the xterm drivers opens a xterm on the host side using port-helper.
Mconsole is the management console.
Please read the documentation.
Thanks,
//richard
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-07-16 16:34 UTC | newest]
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2013-07-16 15:54 [QUERY] User-Mode Linux and /dev/tty* Ramkumar Ramachandra
2013-07-16 15:59 ` Richard Weinberger
2013-07-16 16:03 ` Ramkumar Ramachandra
2013-07-16 16:10 ` Richard Weinberger
2013-07-16 16:26 ` Ramkumar Ramachandra
2013-07-16 16:34 ` Richard Weinberger
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