From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932150Ab1DAPjp (ORCPT ); Fri, 1 Apr 2011 11:39:45 -0400 Received: from ns2.coplanar.net ([199.27.182.4]:37144 "EHLO titan.coplanar.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755508Ab1DAPjo (ORCPT ); Fri, 1 Apr 2011 11:39:44 -0400 Message-ID: <4D95F1B0.9060304@coplanar.net> Date: Fri, 01 Apr 2011 11:39:28 -0400 From: Jeremy Jackson Organization: Coplanar Networks User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.14) Gecko/20110223 Thunderbird/3.1.8 MIME-Version: 1.0 To: Dmitry Torokhov CC: Randy Dunlap , linux-kernel@vger.kernel.org Subject: Re: signal to PID 1 from serial console like KeyboardRequest or CAD References: <4D8CD3D4.90900@coplanar.net> <20110331125706.9159a13d.rdunlap@xenotime.net> <20110401053757.GA9866@core.coreip.homeip.net> In-Reply-To: <20110401053757.GA9866@core.coreip.homeip.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.3.4 (titan.coplanar.net [199.27.182.2]); Fri, 01 Apr 2011 11:39:40 -0400 (EDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. >>> 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