From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39520) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vnqsp-000813-8R for qemu-devel@nongnu.org; Tue, 03 Dec 2013 09:23:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vnqsg-00080W-8U for qemu-devel@nongnu.org; Tue, 03 Dec 2013 09:23:27 -0500 Received: from e23smtp09.au.ibm.com ([202.81.31.142]:50858) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vnqsf-0007vd-IB for qemu-devel@nongnu.org; Tue, 03 Dec 2013 09:23:18 -0500 Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 4 Dec 2013 00:23:14 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 92E463578050 for ; Wed, 4 Dec 2013 01:23:12 +1100 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id rB3E59Gx4915652 for ; Wed, 4 Dec 2013 01:05:09 +1100 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id rB3ENB5o011146 for ; Wed, 4 Dec 2013 01:23:12 +1100 Message-ID: <529DE94C.4070808@linux.vnet.ibm.com> Date: Tue, 03 Dec 2013 22:23:08 +0800 From: Lei Li MIME-Version: 1.0 References: <1385975957-22941-1-git-send-email-lilei@linux.vnet.ibm.com> <1385975957-22941-7-git-send-email-lilei@linux.vnet.ibm.com> <20131202093341.GA1980@redhat.com> <529DBE4C.8060205@linux.vnet.ibm.com> <529DC602.6000702@redhat.com> In-Reply-To: <529DC602.6000702@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 06/17] migration-local: add send_pipefd() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: "aarcange@redhat.com >> Andrea Arcangeli" , quintela@redhat.com, qemu-devel@nongnu.org, mrhines@linux.vnet.ibm.com, aliguori@amazon.com, lagarcia@br.ibm.com, rcj@linux.vnet.ibm.com On 12/03/2013 07:52 PM, Paolo Bonzini wrote: > Il 03/12/2013 12:19, Lei Li ha scritto: >> On 12/02/2013 05:33 PM, Daniel P. Berrange wrote: >>> On Mon, Dec 02, 2013 at 05:19:06PM +0800, Lei Li wrote: >>>> This patch adds send_pipefd() to pass the pipe file descriptor >>>> to destination process. >>>> >>>> Signed-off-by: Lei Li >>>> --- >>>> migration-local.c | 46 >>>> ++++++++++++++++++++++++++++++++++++++++++++++ >>>> 1 files changed, 46 insertions(+), 0 deletions(-) >>>> >>>> diff --git a/migration-local.c b/migration-local.c >>>> index 929ed60..f479530 100644 >>>> --- a/migration-local.c >>>> +++ b/migration-local.c >>>> @@ -167,3 +167,49 @@ fail: >>>> g_free(s); >>>> return NULL; >>>> } >>>> + >>>> + >>>> +/* >>>> + * Pass a pipe file descriptor to another process. >>>> + * >>>> + * Return negative value If pipefd < 0. Return 0 on >>>> + * success. >>>> + * >>>> + */ >>>> +static int send_pipefd(int sockfd, int pipefd) >>>> +{ >>>> + struct msghdr msg; >>>> + struct iovec iov[1]; >>>> + ssize_t ret; >>>> + char req[1] = { 0x01 }; >>>> + >>>> + union { >>>> + struct cmsghdr cm; >>>> + char control[CMSG_SPACE(sizeof(int))]; >>>> + } control_un; >>>> + struct cmsghdr *cmptr; >>>> + >>>> + msg.msg_control = control_un.control; >>>> + msg.msg_controllen = sizeof(control_un.control); >>>> + >>>> + cmptr = CMSG_FIRSTHDR(&msg); >>>> + cmptr->cmsg_len = CMSG_LEN(sizeof(int)); >>>> + cmptr->cmsg_level = SOL_SOCKET; >>>> + cmptr->cmsg_type = SCM_RIGHTS; >>>> + *((int *) CMSG_DATA(cmptr)) = pipefd; >>>> + >>>> + msg.msg_name = NULL; >>>> + msg.msg_namelen = 0; >>>> + >>>> + iov[0].iov_base = req; >>>> + iov[0].iov_len = sizeof(req); >>>> + msg.msg_iov = iov; >>>> + msg.msg_iovlen = 1; >>>> + >>>> + ret = sendmsg(sockfd, &msg, 0); >>>> + if (ret <= 0) { >>>> + DPRINTF("sendmsg error: %s\n", strerror(errno)); >>>> + } >>>> + >>>> + return ret; >>>> +} >>> Just a reminder about my comments from previous posting. This is >>> introducing a 3rd private function for sending FDs. The existing >>> code should be refactored into qemu-socket.{c,h} and shared. >> Hi Daniel, >> >> Yes, I remembered your suggestion. As my reply in the previous version, >> I'll make this refactoring in a separate thread. There are some differences >> between these private functions (like data type and length of bytes >> transmitted), may need a little time to get the common method settle down, >> and would be better to do some test to make sure there is no impact on >> them. > You would have to implement it in such a way that the buffer is > specified in the function, for example: > > ssize_t qemu_send_with_fd(int sockfd, int passed_fd, const void *buf, > size_t len); > ssize_t qemu_recv_with_fd(int sockfd, int *passed_fd, void *buf, > size_t len); > > The functions can go in util/ (I think not in qemu-socket.c, a new file > is preferrable). > > I don't think it's particularly important, but it's definitely welcome. Hi Paolo, Thanks for your specified suggestion! As it needs to test the related code (tap/bridge & Proxy FS & flipping migration), I will work on it after back from my vacation next week. :-) > > Paolo > -- Lei