From owner-freebsd-hackers@FreeBSD.ORG Wed Aug 10 21:38:39 2005 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6635816A41F for ; Wed, 10 Aug 2005 21:38:39 +0000 (GMT) (envelope-from jhb@FreeBSD.org) Received: from mv.twc.weather.com (mv.twc.weather.com [65.212.71.225]) by mx1.FreeBSD.org (Postfix) with ESMTP id F2E5D43D55 for ; Wed, 10 Aug 2005 21:38:38 +0000 (GMT) (envelope-from jhb@FreeBSD.org) Received: from [10.50.40.201] (Not Verified[65.202.103.25]) by mv.twc.weather.com with NetIQ MailMarshal (v6, 0, 3, 8) id ; Wed, 10 Aug 2005 17:53:28 -0400 From: John Baldwin To: freebsd-hackers@freebsd.org Date: Wed, 10 Aug 2005 17:37:35 -0400 User-Agent: KMail/1.8 References: <42FA63A3.4040802@mail.pnpi.spb.ru> <200508101640.28555.jhb@FreeBSD.org> <42FA6D78.4020306@mail.pnpi.spb.ru> In-Reply-To: <42FA6D78.4020306@mail.pnpi.spb.ru> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508101737.36542.jhb@FreeBSD.org> Cc: Sergey Uvarov Subject: Re: preferable way to control kernel module X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Aug 2005 21:38:39 -0000 On Wednesday 10 August 2005 05:11 pm, Sergey Uvarov wrote: > John Baldwin wrote: > > On Wednesday 10 August 2005 04:29 pm, Sergey Uvarov wrote: > >>Hello hackers, > >> > >>I'm writing a kernel module for my own needs. AFAIK the following > >>methods could be used: > >> > >>1) allocate not used system call with help of SYSCALL_MODULE macro > >> > >>2) allocate proprieatry oid via SYSCTL_OID(OID_AUTO) and write an > >>appropriate sysctl handler(s) > >> > >>3) add a file in /dev and use ioctl(2) call > >> > >>What is a preferable way to control my module? > > > > It depends on what you want to do really. I've used sysctl's for simple > > debug modules where I write to the sysctl to have it perform a desired > > action. > > I need to pass some configuration parameters to my module and retrieve a > status back. Interface is quite similar to ptrace(2) syscall. I don't > need to pass large amount of data. If it's a single integer or some such, I'd say use sysctl. If it's a structure, I'd go the ioctl(2) route. Creating /dev entries isn't all that hard. In your case you'd just need open/close/ioctl in a cdevsw, then use make_dev() during MOD_LOAD and destroy_dev() during MOD_UNLOAD. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org