From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34603) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLcvK-00074L-QI for qemu-devel@nongnu.org; Wed, 23 May 2018 19:12:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fLcvH-0004PN-L9 for qemu-devel@nongnu.org; Wed, 23 May 2018 19:12:02 -0400 Received: from mga11.intel.com ([192.55.52.93]:36350) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fLcvH-0004O8-Ax for qemu-devel@nongnu.org; Wed, 23 May 2018 19:11:59 -0400 Date: Thu, 24 May 2018 07:12:15 +0800 From: Tiwei Bie Message-ID: <20180523231215.GA15604@debian> References: <20180412151232.17506-1-tiwei.bie@intel.com> <20180412151232.17506-4-tiwei.bie@intel.com> <20180524002447-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20180524002447-mutt-send-email-mst@kernel.org> Subject: Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 3/6] vhost-user: support receiving file descriptors in slave_read List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: jasowang@redhat.com, alex.williamson@redhat.com, pbonzini@redhat.com, stefanha@redhat.com, qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org, cunming.liang@intel.com, dan.daly@intel.com, jianfeng.tan@intel.com, zhihong.wang@intel.com, xiao.w.wang@intel.com On Thu, May 24, 2018 at 12:25:23AM +0300, Michael S. Tsirkin wrote: > On Thu, Apr 12, 2018 at 11:12:29PM +0800, Tiwei Bie wrote: > > Signed-off-by: Tiwei Bie > > > Thinking about it, I think we should add a protocol > feature for this. This way remote can find out whether > it's safe to send this data to us. Okay, I can add a protocol feature for this. Do you think it's OK to keep this patch as is (this patch just extends slave_read() to support receiving file descriptors) and introduce the new protocol feature in a new patch to allow backends to send file descriptors? Best regards, Tiwei Bie > > > --- > > hw/virtio/vhost-user.c | 41 ++++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 40 insertions(+), 1 deletion(-) > > > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c > > index 91edd95453..9cea2c8c51 100644 > > --- a/hw/virtio/vhost-user.c > > +++ b/hw/virtio/vhost-user.c > > @@ -854,14 +854,44 @@ static void slave_read(void *opaque) > > VhostUserHeader hdr = { 0, }; > > VhostUserPayload payload = { 0, }; > > int size, ret = 0; > > + struct iovec iov; > > + struct msghdr msgh; > > + int fd = -1; > > + char control[CMSG_SPACE(sizeof(fd))]; > > + struct cmsghdr *cmsg; > > + size_t fdsize; > > + > > + memset(&msgh, 0, sizeof(msgh)); > > + msgh.msg_iov = &iov; > > + msgh.msg_iovlen = 1; > > + msgh.msg_control = control; > > + msgh.msg_controllen = sizeof(control); > > > > /* Read header */ > > - size = read(u->slave_fd, &hdr, VHOST_USER_HDR_SIZE); > > + iov.iov_base = &hdr; > > + iov.iov_len = VHOST_USER_HDR_SIZE; > > + > > + size = recvmsg(u->slave_fd, &msgh, 0); > > if (size != VHOST_USER_HDR_SIZE) { > > error_report("Failed to read from slave."); > > goto err; > > } > > > > + if (msgh.msg_flags & MSG_CTRUNC) { > > + error_report("Truncated message."); > > + goto err; > > + } > > + > > + for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg != NULL; > > + cmsg = CMSG_NXTHDR(&msgh, cmsg)) { > > + if (cmsg->cmsg_level == SOL_SOCKET && > > + cmsg->cmsg_type == SCM_RIGHTS) { > > + fdsize = cmsg->cmsg_len - CMSG_LEN(0); > > + memcpy(&fd, CMSG_DATA(cmsg), fdsize); > > + break; > > + } > > + } > > + > > if (hdr.size > VHOST_USER_PAYLOAD_SIZE) { > > error_report("Failed to read msg header." > > " Size %d exceeds the maximum %zu.", hdr.size, > > @@ -885,9 +915,15 @@ static void slave_read(void *opaque) > > break; > > default: > > error_report("Received unexpected msg type."); > > + if (fd != -1) { > > + close(fd); > > + } > > ret = -EINVAL; > > } > > > > + /* Message handlers need to make sure that fd will be consumed. */ > > + fd = -1; > > + > > /* > > * REPLY_ACK feature handling. Other reply types has to be managed > > * directly in their request handlers. > > @@ -920,6 +956,9 @@ err: > > qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL); > > close(u->slave_fd); > > u->slave_fd = -1; > > + if (fd != -1) { > > + close(fd); > > + } > > return; > > } > > > > -- > > 2.11.0 > > --------------------------------------------------------------------- > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org >