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Re: [Qemu-devel] [PATCH v3 3/6] vhost-user: support receiving file descr
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v3 3/6] vhost-user: support receiving file descriptors in slave_read |
Date: |
Thu, 24 May 2018 00:25:23 +0300 |
On Thu, Apr 12, 2018 at 11:12:29PM +0800, Tiwei Bie wrote:
> Signed-off-by: Tiwei Bie <address@hidden>
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.
> ---
> 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
- Re: [Qemu-devel] [PATCH v3 3/6] vhost-user: support receiving file descriptors in slave_read,
Michael S. Tsirkin <=