From patchwork Thu Mar 31 14:57:10 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 8713991 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id EFACE9F39A for ; Thu, 31 Mar 2016 14:57:21 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8239920279 for ; Thu, 31 Mar 2016 14:57:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F94520272 for ; Thu, 31 Mar 2016 14:57:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757317AbcCaO5N (ORCPT ); Thu, 31 Mar 2016 10:57:13 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:55106 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757292AbcCaO5L (ORCPT ); Thu, 31 Mar 2016 10:57:11 -0400 Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 7235C8EE341; Thu, 31 Mar 2016 07:57:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1459436231; bh=1SAEo3jS76iOLyN/66BRRqdAIaPpKxITk6WxYgOfKzY=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=oDYras3Opx1ZqiamPoFlVHJH1i9xVcj0ITJ8VZqaf0ZpJbRQoFo3F2bBNIiAvIygD +kNpAvvpml+pazv8CDXfOR9mMNbkSjyFViK+AYrUQlc6U62AEqQSzRwGWEEUNSQ/ca jC82ZHQjQyOl0E4EUPg68ox+JeeJqKYQevf/QbUs= Received: from bedivere.hansenpartnership.com ([127.0.0.1]) by localhost (bedivere.hansenpartnership.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id oVVVHwgYoKn6; Thu, 31 Mar 2016 07:57:11 -0700 (PDT) Received: from [10.0.6.30] (unknown [64.55.107.3]) by bedivere.hansenpartnership.com (Postfix) with ESMTPSA id 15C508EE0CD; Thu, 31 Mar 2016 07:57:11 -0700 (PDT) Message-ID: <1459436230.2958.24.camel@HansenPartnership.com> Subject: [Patch v3 3/3] binfmt_misc: add F option description to documentation From: James Bottomley To: containers@lists.linux-foundation.org, linux-fsdevel Cc: Al Viro , Jan Kara Date: Thu, 31 Mar 2016 07:57:10 -0700 In-Reply-To: <1459436046.2958.21.camel@HansenPartnership.com> References: <1459436046.2958.21.camel@HansenPartnership.com> X-Mailer: Evolution 3.16.5 Mime-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-7.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Signed-off-by: James Bottomley --- Documentation/binfmt_misc.txt | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/binfmt_misc.txt b/Documentation/binfmt_misc.txt index 6b1de70..ec83bbc 100644 --- a/Documentation/binfmt_misc.txt +++ b/Documentation/binfmt_misc.txt @@ -66,6 +66,13 @@ Here is what the fields mean: This feature should be used with care as the interpreter will run with root permissions when a setuid binary owned by root is run with binfmt_misc. + 'F' - fix binary. The usual behaviour of binfmt_misc is to spawn the + binary lazily when the misc format file is invoked. However, + this doesn't work very well in the face of mount namespaces and + changeroots, so the F mode opens the binary as soon as the + emulation is installed and uses the opened image to spawn the + emulator, meaning it is always available once installed, + regardless of how the environment changes. There are some restrictions: