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=-6.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 5A345C433EF for ; Tue, 14 Sep 2021 20:38:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 336676108F for ; Tue, 14 Sep 2021 20:38:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233416AbhINUjv (ORCPT ); Tue, 14 Sep 2021 16:39:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:45382 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233426AbhINUjs (ORCPT ); Tue, 14 Sep 2021 16:39:48 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8FFA560FED; Tue, 14 Sep 2021 20:38:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631651910; bh=GwJPjD/GwPL/DwGjqr1yZKsemUFxl/JzTMaSJkQLQ4o=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=udVS1LWhWGEmrVCAlNg1T51i1QJ9fV7/V9+31rOEYM+TFo7bqzgQSJKftSiSnGquJ bc7NkOA+RtugoEiW1JBRdCB6bugT99bspx1JipUa0A0HCeb+mpfXBcFKt4ZPtMakcM n4tjSGw8E+RcZm5PzEYzsPJOsQMukpryPkkZyQBgchaWH9VgOt6ohWyiPbuKAIpkVC ydz5F3bPI+lmiM73kKXqJ1lLMdoRIiFuT6Wk6EHcp4EqXgQJVE0pf/Fn2iCWZNQ7Oy wfB/+pD0+rdJEyOIsk2e2ApXCtmvrzUmfwW0VIEI0be6Zp54b559VoNWjbYhRZtOyX VqawGvTHrYXZQ== Date: Tue, 14 Sep 2021 15:38:29 -0500 From: Bjorn Helgaas To: Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= Cc: Bjorn Helgaas , Lorenzo Pieralisi , Kishon Vijay Abraham I , linux-pci@vger.kernel.org Subject: Re: [PATCH v2 1/4] PCI/sysfs: Move to kstrtobool() to handle user input Message-ID: <20210914203829.GA1454594@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210706010622.3058968-1-kw@linux.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Tue, Jul 06, 2021 at 01:06:19AM +0000, Krzysztof Wilczyński wrote: > A common use case for many PCI sysfs objects is to either enable some > functionality or trigger an action following a write to a given > attribute where the value is written would be simply either "1" or "0" > synonymous with either disabling or enabling something. > > Parsing and validation of the input values are currently done using the > kstrtoul() function to convert anything in the string buffer into an > integer value - anything non-zero would be accepted as "enable" and zero > simply as "disable". > > For a while now, the kernel offers another function called kstrtobool() > which was created to parse common user inputs into a boolean value, so > that a range of values such as "y", "n", "1", "0", "on" and "off" > handled in a case-insensitive manner would yield a boolean true or false > result accordingly after the input string has been parsed. > > Thus, move to kstrtobool() over kstrtoul() as it's a better fit for > parsing user input, and it also implicitly offers a range check as only > a finite amount of possible input values will be considered as valid. If I understand correctly, a user could enable things by writing "5" today, and if we switch to kstrbool(), that will no longer work. I'm sure everything is *documented* such that one should write "1" or other sensible values. But I'm not sure there's benefit in adding new restrictions. Bjorn