From owner-freebsd-current@FreeBSD.ORG Sat Jan 10 08:08:36 2009 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 65B4B106566C for ; Sat, 10 Jan 2009 08:08:36 +0000 (UTC) (envelope-from heliocentric@gmail.com) Received: from yx-out-2324.google.com (yx-out-2324.google.com [74.125.44.29]) by mx1.freebsd.org (Postfix) with ESMTP id 1B0818FC1C for ; Sat, 10 Jan 2009 08:08:35 +0000 (UTC) (envelope-from heliocentric@gmail.com) Received: by yx-out-2324.google.com with SMTP id 8so4109289yxb.13 for ; Sat, 10 Jan 2009 00:08:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:sender :to:subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references :x-google-sender-auth; bh=TPM52Jl79eCOiyvf8CJBoiaxhd9aK6oIKWYyAsFEgHI=; b=bMfzXLNLIkH3+fTryYEMt/NxvDC7wHEmpuS8qJ61fQ2YMDOwGN5gp62N8Hb4J3786z PwGXMvueobuL0zaDVK761KpfCjHQto61pjnHMOIPP/lUY/HzuBmNIEfJuEm/QQUmhIc2 RqOF89RN1LmRfKPkvEQlTMJTZSFi+NF8N5XCQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references:x-google-sender-auth; b=mLQKF2Bq4OYpIEU1TBSmw958W1Zgq4Z6oq2jNoileewv6g/OTmRnAq2u/0ozV23GPF BPr0FZEBwxeGHnPN59kkEzDrg1an3Vux2FVI1d8QUngeRPUFkEi6GwtV5bLy6c6UCK0V /iEVW0rpJenb5gH2DvoTlcvkWIIyQ3hv/73uU= Received: by 10.90.68.20 with SMTP id q20mr12583692aga.75.1231573291413; Fri, 09 Jan 2009 23:41:31 -0800 (PST) Received: by 10.90.36.7 with HTTP; Fri, 9 Jan 2009 23:41:31 -0800 (PST) Message-ID: Date: Sat, 10 Jan 2009 02:41:31 -0500 From: "Dylan Cochran" Sender: heliocentric@gmail.com To: "Tim Kientzle" In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <4965927D.1060507@freebsd.org> X-Google-Sender-Auth: f4e0b8e47f27dc73 Cc: freebsd-current@freebsd.org Subject: Re: Extattr portability? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 10 Jan 2009 08:08:36 -0000 On Fri, Jan 9, 2009 at 10:27 AM, Robert Watson wrote: > On Wed, 7 Jan 2009, Tim Kientzle wrote: > >> I'm trying to complete the extended attribute support in libarchive. >> There are a handful of odd issues that arise which I think I could resolve >> if I knew of good use cases. >> >> Anyone here actually use extended attributes? (Note that ACLs are handled >> separately.) What software? What information do you store there? >> >> If you could benefit from being able to move extended attributes between >> FreeBSD and other systems, I'm especially interested. > > Most (all) of the use of extended attributes that I'm aware of on FreeBSD > relates to security extensions, be it ACLs, MAC labels (almost always in the > system namespace) for various policies, etc. Mac OS X is now using extended > attributes in quite a few more ways, however, so you may want to investigate > a bit on that side. Most uses I'm aware of aren't intended to be portable. Another is BeOS/Haiku, which used attributes heavily. I have been waiting for this work for a while. What I don't really mind is whether it is portable, what I really care about is full retention of the user namespace. No silent truncating of an attribute because of perceived need for a size restriction, assuming the contents are only ASCII, etc. If setextattr can set it on a file, tar should be able to retain it as is, and extract it so getextattr later is identical. If that can be done using an already defined extended attribute format, great! If it can't, I can live with an incompatible tar format. That's my 2 cents on the matter, I use extended attributes now for storing cached mime-type, and sha256/md5 for checksum purposes. I have plans sometime in the future to create a patch for ROX-Filer to check for thumbnail and icon attributes, and use them instead of the current cache scheme. Being able to tar up the directory, and then extract it and keep the thumbnail/icon as expected, would greatly improve user experience, in my opinion.