From owner-freebsd-hackers@FreeBSD.ORG Thu Apr 29 18:18:53 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3745C106566C for ; Thu, 29 Apr 2010 18:18:53 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 0743B8FC19 for ; Thu, 29 Apr 2010 18:18:53 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id AB8A446B03; Thu, 29 Apr 2010 14:18:52 -0400 (EDT) Received: from jhbbsd.localnet (smtp.hudson-trading.com [209.249.190.9]) by bigwig.baldwin.cx (Postfix) with ESMTPA id B5D6B8A021; Thu, 29 Apr 2010 14:18:51 -0400 (EDT) From: John Baldwin To: freebsd-hackers@freebsd.org Date: Thu, 29 Apr 2010 14:18:09 -0400 User-Agent: KMail/1.12.1 (FreeBSD/7.3-CBSD-20100217; KDE/4.3.1; amd64; ; ) References: In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <201004291418.09768.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Thu, 29 Apr 2010 14:18:51 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-2.6 required=4.2 tests=AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: =?utf-8?q?Luk=C3=A1=C5=A1?= Czerner Subject: Re: ioctl, copy string from user 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: Thu, 29 Apr 2010 18:18:53 -0000 On Thursday 29 April 2010 1:52:45 pm Luk=C3=A1=C5=A1 Czerner wrote: > Hi, >=20 > I know that there are plenty of examples in the kernel code, but I > just can not get it working, so maybe I am doing some stupid mistake > I am not aware of. Please give me a hint if you can. >=20 > What I want to do is simply call the ioctl from the userspace with > (char *) argument. Then, in kernel ioctl handling function copy the > string argument into the kernel space. I have tried it various ways, > everything without any success. >=20 > *** Userspace *** > char name[MAXLEN]; >=20 > strncpy(name, argv[1], MAXLEN); > fprintf(stdout,"Name: %s\n",name); >=20 > if (ioctl(fd, MYIOCTL, name)) { On BSD systems, ioctl() copies the data into the kernel for you ahead of ti= me. =20 What does the definition of MYIOCTL look like? > And the second question. I have commented that I can allocate buffer > dynamically, but I suppose that there will be some locks involved so > I think I can not just use M_WAITOK, am I right ? malloc() and free() acquire their own locks internally, you do not need to= =20 hold any locks to call them. =2D-=20 John Baldwin