Re: [PATCH for-9.1 v2 01/11] libvhost-user: set msg.msg_control to NULL when it is empty

[Eric Blake]

On Tue, Mar 26, 2024 at 02:39:26PM +0100, Stefano Garzarella wrote:
> On some OS (e.g. macOS) sendmsg() returns -1 (errno EINVAL) if
> the `struct msghdr` has the field `msg_controllen` set to 0, but
> `msg_control` is not NULL.
> 
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>  subprojects/libvhost-user/libvhost-user.c | 1 +
>  1 file changed, 1 insertion(+)

Reviewed-by: Eric Blake <eblake@redhat.com>

> 
> diff --git a/subprojects/libvhost-user/libvhost-user.c 
> b/subprojects/libvhost-user/libvhost-user.c
> index a879149fef..22bea0c775 100644
> --- a/subprojects/libvhost-user/libvhost-user.c
> +++ b/subprojects/libvhost-user/libvhost-user.c
> @@ -632,6 +632,7 @@ vu_message_write(VuDev *dev, int conn_fd, VhostUserMsg 
> *vmsg)
>          memcpy(CMSG_DATA(cmsg), vmsg->fds, fdsize);
>      } else {
>          msg.msg_controllen = 0;
> +        msg.msg_control = NULL;
>      }
>  
>      do {
> -- 
> 2.44.0
> 

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.
Virtualization:  qemu.org | libguestfs.org