From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756558Ab1DAPmW (ORCPT ); Fri, 1 Apr 2011 11:42:22 -0400 Received: from cpoproxy1-pub.bluehost.com ([69.89.21.11]:53995 "HELO outbound-mail-01.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750777Ab1DAPmU (ORCPT ); Fri, 1 Apr 2011 11:42:20 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=default; d=xenotime.net; h=Received:Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References:Organization:X-Mailer:Mime-Version:Content-Type:Content-Transfer-Encoding:X-Identified-User; b=t5ytFk8/XEy9/d0aBE9jDWnS/NL3dWkemJskivlt6JoqVTYf5i3EifjJwZZCDuqp8UdM13uSfPy+orzlSIqU6jxnQc7XK2JTrhCvy0+r2f4zi2QR29LxH8YcXtm77Kcs; Date: Fri, 1 Apr 2011 08:42:18 -0700 From: Randy Dunlap To: Jeremy Jackson Cc: Dmitry Torokhov , linux-kernel@vger.kernel.org Subject: Re: signal to PID 1 from serial console like KeyboardRequest or CAD Message-Id: <20110401084218.d803b38d.rdunlap@xenotime.net> In-Reply-To: <4D95F1B0.9060304@coplanar.net> References: <4D8CD3D4.90900@coplanar.net> <20110331125706.9159a13d.rdunlap@xenotime.net> <20110401053757.GA9866@core.coreip.homeip.net> <4D95F1B0.9060304@coplanar.net> Organization: YPO4 X-Mailer: Sylpheed 2.7.1 (GTK+ 2.16.6; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Identified-User: {1807:box742.bluehost.com:xenotime:xenotime.net} {sentby:smtp auth 50.53.38.135 authed with rdunlap@xenotime.net} Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 01 Apr 2011 11:39:28 -0400 Jeremy Jackson wrote: > On 04/01/2011 01:37 AM, Dmitry Torokhov wrote: > > On Thu, Mar 31, 2011 at 12:57:06PM -0700, Randy Dunlap wrote: > >> On Fri, 25 Mar 2011 13:41:40 -0400 Jeremy Jackson wrote: > >> > >>> Hi, > >>> > >>> Sent to linux-console with no reply for over a week... > >>> > >>> I ran into a problem recently on a Linux server with a remote serial > >>> console. /sbin/init (actually Upstart) was in a state where nothing > >>> (useful) was running. I had to power cycle the machine to get back to > >>> the boot prompt. This has the side-effect of triggering raid rebuilds. > >>> > >>> It would be nice to have what Ctrl-Alt-Del does at the VGA console with > >>> PS/2 or USB keyboard. This sends a SIGINT to PID 1, and most distros > >>> have this set to do "shutdown -r now" which attempts a clean reboot. > >> > >> so C_A_D works at console via PS/2 or USB keyboard, but not on a remote > >> serial console? Could it be an issue with whatever remote/serial software > >> you are using? > > > > I believe it is simply a matter of console keymap and assigning "boot" > > value to the desired combination. > > The VGA console/keyboard isn't an issue here, C_A_D works great. The > problem is, that functionality isn't available when using *serial* console. That's why I asked whether it could be an issue with the serial interface software. E.g., minicom handles/processes certain keystrokes, other apps do things differently, etc... > >>> Once upon a time there was KeyboardRequest, which would send a SIGWINCH > >>> to PID 1 (when pressing Alt-UP_arrow?). I don't see any sign of this > >>> feature in Linux 2.6.32 though. > >> > >> I couldn't find it in 2.4.37 either. > >> > >> Can 'loadkeys' help you any? > >> > >>> Looking at the Sysrq handlers in the kernel I don't see any keystrokes > >>> that send SIGINT to PID 1 either. > >>> > >>> So, I'm wondering if it makes sense to add a Sysrq key to send a signal > >>> to PID1 ? > >> > >> Dmitry, any ideas? > > > > We have SysRq bindings to unmount filesystems and reboot, isn't that > > enough? > > Reboot isn't clean... it doesn't signal MD-raid to "unmount" does it? > SysRq powerOff does cleanly shutdown md-raid, but who will drive to the > datacenter to press the power button to turn it back on? > > I guess there are two ways to achieve clean (md-raid) reboot when using > serial console... a new SysRq to reboot "clean", or a new SysRq to > signal init. Looking at ctrlaltdel(8), perhaps it could just one SysRq, > and let userspace (/sbin/init) configure it as needed. > > > -- > Coplanar Networks > http://www.coplanar.net > (519)489-4903 > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ --- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code ***