Re: [Qemu-devel] [Bug 1626972] Re: [PATCH] util: secure memfd_create fallback mechanism

[Rafael David Tinoco]

Yes, definitely. Check this:

/**
 * @qemu_chr_fe_set_msgfds:
 *
 * For backends capable of fd passing, set an array of fds to be passed with
 * the next send operation.
 * A subsequent call to this function before calling a write function will
 * result in overwriting the fd array with the new value without being send.
 * Upon writing the message the fd array is freed.
 *
 * Returns: -1 if fd passing isn't supported.
 */
int qemu_chr_fe_set_msgfds(CharDriverState *s, int *fds, int num);

----

So, at least for vhost_dev_log_resize, this "interface" is being implemented:

vhost_user_set_log_base -> VhostUserMsg = VHOST_USER_SET_LOG_BASE

vhost_user_write(with the VHOST_USER_GET_LOG_BASE message):

- configures the file descriptors(... , fds, fd_num)
  qemu_chr_fe_set_msgfds

- writes them down the char driver
  qemu_chr_fe_write_all

> On Oct 03, 2016, at 15:46, Rafael David Tinoco <address@hidden> wrote:
> 
>> So you're saying that the file descriptor here is actually getting
>> passed to a different process for it to use ?