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=-6.7 required=3.0 tests=DKIM_ADSP_ALL,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 3A041C282DE for ; Wed, 5 Jun 2019 08:39:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1403D208CA for ; Wed, 5 Jun 2019 08:39:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=cs.msu.ru header.i=@cs.msu.ru header.b="h4Eh3owQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726826AbfFEIjG (ORCPT ); Wed, 5 Jun 2019 04:39:06 -0400 Received: from mx.cs.msu.ru ([188.44.42.42]:50334 "EHLO mail.cs.msu.ru" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726554AbfFEIjF (ORCPT ); Wed, 5 Jun 2019 04:39:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=cs.msu.ru; s=dkim; h=Subject:Content-Transfer-Encoding:Content-Type:MIME-Version: Message-Id:Date:Cc:To:From:Sender:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: In-Reply-To:References:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=Px/uehKk6pJuFy+aIZjSZmKKKoFS+/3im61p33sMu30=; b=h4Eh3owQAMheBMo2vdna3mYbww qUnB4wwLd8cv78+2tpdWfund7vMNdBm1qqzs4C7LgiIOF4XGRCnHfOwCHFlFgqmJLAbTM9ORocQV0 /OaVYWxMK+Djp/E64u4Ii+zHz6jJ9ctvLz1YwG1J7gTSrJmgoCpCnQtayeKhp+aSAzTYZwx6svqyK r/GjocoDVzlqzBN0JFAQ1/o7TzsLBuuxSj59bmV56qy9yT6qMXo2vIh/5vk5aKe6EMwnxWji+Fddg DJWim0OQuzdJA6HUDI+61tlrbkjRPbDlznPeC+y9OgGa1KQ0RY5NE4NWqyvJV4Kl8cTv4z/EmeIiV EfLOKeGw==; Received: from [37.204.119.143] (port=55354 helo=localhost.localdomain) by mail.cs.msu.ru with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.92 (FreeBSD)) (envelope-from ) id 1hYR9H-0008s7-ME; Wed, 05 Jun 2019 11:19:57 +0300 From: Arseny Maslennikov To: Greg Kroah-Hartman , Jiri Slaby , Ingo Molnar , Peter Zijlstra , linux-kernel@vger.kernel.org Cc: "Vladimir D . Seleznev" , Arseny Maslennikov Date: Wed, 5 Jun 2019 11:18:59 +0300 Message-Id: <20190605081906.28938-1-ar@cs.msu.ru> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 37.204.119.143 X-SA-Exim-Mail-From: ar@cs.msu.ru Subject: [PATCH 0/7] TTY Keyboard Status Request X-SA-Exim-Version: 4.2 X-SA-Exim-Scanned: No (on mail.cs.msu.ru); Unknown failure Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch series introduces TTY keyboard status request, a feature of the n_tty line discipline that reserves a character in struct termios (^T by default) and reacts to it by printing a short informational line to the terminal and sending a Unix signal to the tty's foreground process group. The processes may, in response to the signal, output a textual description of what they're doing. The feature has been present in a similar form at least in Free/Open/NetBSD; it would be nice to have something like this in Linux as well. There is an LKML thread[1] where users have previously expressed the rationale for this. The current implementation does not break existing kernel API in any way, since, fortunately, all the architectures supported by the kernel happen to have at least 1 free byte in the termios control character array. The series should cleanly apply to tty-next. To thoroughly test these, one might need at least a patched stty among other tools, so I've brought up a simple initrd generator[2] which can be used to create a lightweight environment to boot up in a VM and to fiddle with. [1] https://lore.kernel.org/lkml/1415200663.3247743.187387481.75CE9317@webmail.messagingengine.com/ [2] https://github.com/porrided/tty-kb-status-userspace Arseny Maslennikov (7): signal.h: Define SIGINFO on all architectures tty: termios: Reserve space for VSTATUS in .c_cc n_tty: Send SIGINFO to fg pgrp on status request character linux/signal.h: Ignore SIGINFO by default in new tasks tty: Add NOKERNINFO lflag to termios n_tty: ->ops->write: Cut core logic out to a separate function n_tty: Provide an informational line on VSTATUS receipt arch/alpha/include/asm/termios.h | 4 +- arch/alpha/include/uapi/asm/termbits.h | 2 + arch/arm/include/uapi/asm/signal.h | 1 + arch/h8300/include/uapi/asm/signal.h | 1 + arch/ia64/include/asm/termios.h | 4 +- arch/ia64/include/uapi/asm/signal.h | 1 + arch/ia64/include/uapi/asm/termbits.h | 2 + arch/m68k/include/uapi/asm/signal.h | 1 + arch/mips/include/asm/termios.h | 4 +- arch/mips/include/uapi/asm/signal.h | 1 + arch/mips/include/uapi/asm/termbits.h | 2 + arch/parisc/include/asm/termios.h | 4 +- arch/parisc/include/uapi/asm/signal.h | 1 + arch/parisc/include/uapi/asm/termbits.h | 2 + arch/powerpc/include/asm/termios.h | 4 +- arch/powerpc/include/uapi/asm/signal.h | 1 + arch/powerpc/include/uapi/asm/termbits.h | 2 + arch/s390/include/asm/termios.h | 4 +- arch/s390/include/uapi/asm/signal.h | 1 + arch/sparc/include/asm/termios.h | 4 +- arch/sparc/include/uapi/asm/signal.h | 2 + arch/sparc/include/uapi/asm/termbits.h | 2 + arch/x86/include/uapi/asm/signal.h | 1 + arch/xtensa/include/uapi/asm/signal.h | 1 + arch/xtensa/include/uapi/asm/termbits.h | 2 + drivers/tty/Makefile | 3 +- drivers/tty/n_tty.c | 69 ++++- drivers/tty/n_tty_status.c | 363 +++++++++++++++++++++++ include/asm-generic/termios.h | 4 +- include/linux/signal.h | 5 +- include/linux/tty.h | 7 +- include/uapi/asm-generic/signal.h | 1 + include/uapi/asm-generic/termbits.h | 2 + 33 files changed, 475 insertions(+), 33 deletions(-) create mode 100644 drivers/tty/n_tty_status.c -- 2.20.1