From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D8A0CC433E0 for ; Tue, 4 Aug 2020 16:25:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C68302070A for ; Tue, 4 Aug 2020 16:25:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729973AbgHDQZU (ORCPT ); Tue, 4 Aug 2020 12:25:20 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:34168 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729877AbgHDQYK (ORCPT ); Tue, 4 Aug 2020 12:24:10 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: andrzej.p) with ESMTPSA id 971BB2950F5 From: Andrzej Pietrasiewicz To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , Jiri Slaby , Dmitry Torokhov , Andrzej Pietrasiewicz , linux-input@vger.kernel.org, kernel@collabora.com Subject: [PATCH 0/2] Add configurable handler to execute a compound action Date: Tue, 4 Aug 2020 18:24:00 +0200 Message-Id: <20200804162402.2087-1-andrzej.p@collabora.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Patch 2/2 adds a configurable handler to execute a compound action. Userland might want to execute e.g. 'w' (show blocked tasks), followed by 's' (sync), followed by 1000 ms delay and then followed by 'c' (crash) upon a single magic SysRq. Or one might want to execute the famous "Raising Elephants Is So Utterly Boring" action. This patch adds a configurable handler, triggered with 'C', for this exact purpose. The user specifies the composition of the compound action using syntax similar to getopt, where each letter corresponds to an individual action and a colon followed by a number corresponds to a delay of that many milliseconds, e.g.: ws:1000c or r:100eis:1000ub An example of userspace that wants to perform a compound action is Chrome OS, where SysRq-X (pressed for the second time within a certain time period from the first time) causes showing the locked tasks, syncing, waiting a 1000 ms delay and crashing the system. Since all the slots in the sysrq_key_table[] are already taken or reserved, patch 1/2 extends it to cover also capital letter versions. Andrzej Pietrasiewicz (2): tty/sysrq: Extend the sysrq_key_table to cover capital letters tty/sysrq: Add configurable handler to execute a compound action Documentation/admin-guide/sysrq.rst | 11 +++ drivers/tty/sysrq.c | 128 +++++++++++++++++++++++++++- include/linux/sysrq.h | 1 + 3 files changed, 138 insertions(+), 2 deletions(-) base-commit: bcf876870b95592b52519ed4aafcf9d95999bc9c -- 2.17.1