linux-kernel - Re: signal to PID 1 from serial console like KeyboardRequest or CAD

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20110331125706.9159a13d.rdunlap@xenotime.net>
Date:	Thu, 31 Mar 2011 12:57:06 -0700
From:	Randy Dunlap <rdunlap@...otime.net>
To:	Jeremy Jackson <jerj@...lanar.net>
Cc:	linux-kernel@...r.kernel.org,
	Dmitry Torokhov <dmitry.torokhov@...il.com>
Subject: Re: signal to PID 1 from serial console like KeyboardRequest or CAD

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?

> 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?


---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/