Re: [PATCH 05/15] python/qmp: add send_fd_scm directly to QEMUMonitorProtocol

[Hanna Reitz]

On 17.09.21 07:40, John Snow wrote:
> It turns out you can do this directly from Python ... and because of
> this, you don't need to worry about setting the inheritability of the
> fds or spawning another process.
>
> Doing this is helpful because it allows QEMUMonitorProtocol to keep its
> file descriptor and socket object as private implementation details.
>
> *that* is helpful in turn because it allows me to write a compatible,
>   alternative implementation.

Bit of a weird indentation here.

> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>   python/qemu/machine/machine.py | 44 +++++++---------------------------
>   python/qemu/qmp/__init__.py    | 21 +++++++---------
>   2 files changed, 18 insertions(+), 47 deletions(-)
>
> diff --git a/python/qemu/machine/machine.py b/python/qemu/machine/machine.py
> index ae945ca3c9..1c6532a3d6 100644
> --- a/python/qemu/machine/machine.py
> +++ b/python/qemu/machine/machine.py
> @@ -213,48 +213,22 @@ def add_fd(self: _T, fd: int, fdset: int,
>       def send_fd_scm(self, fd: Optional[int] = None,
>                       file_path: Optional[str] = None) -> int:

[...]

>           if file_path is not None:
>               assert fd is None
> -            fd_param.append(file_path)
> +            with open(file_path, "rb") as passfile:
> +                fd = passfile.fileno()
> +                self._qmp.send_fd_scm(fd)

Seems a bit strange to send an fd that is then immediately closed, but 
that’s what socket_scm_helper did, and so it looks like the fd is 
effectively duplicated.  OK then.

Reviewed-by: Hanna Reitz <hreitz@redhat.com>