From patchwork Wed Mar 27 09:10:46 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 231617 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id D4D8B2C007C for ; Wed, 27 Mar 2013 20:14:33 +1100 (EST) Received: from localhost ([::1]:39879 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UKmRD-0003zG-Tc for incoming@patchwork.ozlabs.org; Wed, 27 Mar 2013 05:14:31 -0400 Received: from eggs.gnu.org ([208.118.235.92]:54996) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UKmQ4-0002nm-JT for qemu-devel@nongnu.org; Wed, 27 Mar 2013 05:13:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UKmNo-0001VO-R1 for qemu-devel@nongnu.org; Wed, 27 Mar 2013 05:11:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:64919) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UKmNo-0001VH-Gi for qemu-devel@nongnu.org; Wed, 27 Mar 2013 05:11:00 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r2R9At6o012067 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 27 Mar 2013 05:10:55 -0400 Received: from localhost (dhcp-64-106.muc.redhat.com [10.32.64.106]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r2R9AsaM022621; Wed, 27 Mar 2013 05:10:55 -0400 From: Stefan Hajnoczi To: Date: Wed, 27 Mar 2013 10:10:46 +0100 Message-Id: <1364375446-24180-5-git-send-email-stefanha@redhat.com> In-Reply-To: <1364375446-24180-1-git-send-email-stefanha@redhat.com> References: <1364375446-24180-1-git-send-email-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Anthony Liguori , Juan Quintela , mprivozn@redhat.com, coreyb@linux.vnet.ibm.com, david.pravec@nethost.cz, Luiz Capitulino , Stefan Hajnoczi Subject: [Qemu-devel] [PATCH v2 4/4] chardev: clear O_NONBLOCK on SCM_RIGHTS file descriptors X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org When we receive a file descriptor over a UNIX domain socket the O_NONBLOCK flag is preserved. Clear the O_NONBLOCK flag and rely on QEMU file descriptor users like migration, SPICE, VNC, block layer, and others to set non-blocking only when necessary. This change ensures we don't accidentally expose O_NONBLOCK in the QMP API. QMP clients should not need to get the non-blocking state "correct". A recent real-world example was when libvirt passed a non-blocking TCP socket for migration where we expected a blocking socket. The source QEMU produced a corrupted migration stream since its code did not cope with non-blocking sockets. Signed-off-by: Stefan Hajnoczi --- qemu-char.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/qemu-char.c b/qemu-char.c index 500a582..091f2dc 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -2434,6 +2434,9 @@ static void unix_process_msgfd(CharDriverState *chr, struct msghdr *msg) if (fd < 0) continue; + /* O_NONBLOCK is preserved across SCM_RIGHTS so reset it */ + qemu_set_block(fd); + #ifndef MSG_CMSG_CLOEXEC qemu_set_cloexec(fd); #endif