Hi Markus On Fri, Feb 17, 2023 at 1:49 PM Markus Armbruster <arm...@redhat.com> wrote: > > marcandre.lur...@redhat.com writes: > > > From: Marc-André Lureau <marcandre.lur...@redhat.com> > > > > A process with enough capabilities can duplicate a socket to QEMU. > > Modify 'getfd' to import it and add it to the monitor fd list, so it can > > be later used by other commands. > > > > Note that we actually store the SOCKET in the FD list, appropriate care > > must now be taken to use the correct socket functions (similar approach > > is taken by our io/ code and in glib, this is internal and shouldn't > > affect the QEMU/QMP users) > > > > Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com> > > --- > > qapi/misc.json | 16 ++++++++-- > > monitor/fds.c | 79 ++++++++++++++++++++++++++++++++++++---------- > > monitor/hmp-cmds.c | 6 +++- > > 3 files changed, 81 insertions(+), 20 deletions(-) > > > > diff --git a/qapi/misc.json b/qapi/misc.json > > index 27ef5a2b20..cd36d8befb 100644 > > --- a/qapi/misc.json > > +++ b/qapi/misc.json > > @@ -249,10 +249,18 @@ > > ## > > # @getfd: > > # > > -# Receive a file descriptor via SCM rights and assign it a name > > +# On UNIX, receive a file descriptor via SCM rights and assign it a name. > > +# > > +# On Windows, (where ancillary socket fd-passing isn't an option yet), add > > a > > +# socket that was duplicated to QEMU process with WSADuplicateSocketW() via > > +# WSASocket() & WSAPROTOCOL_INFOW structure and assign it a name. A SOCKET > > is > > +# considered as a kind of "file descriptor" in QMP context, for historical > > +# reasons and simplicity. QEMU takes care to use socket functions > > appropriately. > > The Windows part explains things in terms of the C socket API. Less > than ideal for the QEMU QMP Reference Manual, isn't it? I don't know > nearly enough about this stuff to suggest concrete improvements...
We don't have to, after all we don't explain how to use sendmsg/cmsg stuff to pass FDs. I will drop the part about "A SOCKET is considered as a kind of "file descriptor" in QMP context", after we get "[PATCH 0/4] win32: do not mix SOCKET and fd space" (https://patchew.org/QEMU/20230212204942.1905959-1-marcandre.lur...@redhat.com/) merged. > > What does this command do under Windows before this patch? Fail always? Without ancillary data support on Windows, you can't make it work. > > Wrap your lines a bit earlier, please. > > > # > > # @fdname: file descriptor name > > # > > +# @wsa-info: a WSAPROTOCOL_INFOW structure (encoded in base64). Since 8.0. > > +# > > No way around passing a binary blob? WSAPROTOCOL_INFOW is a fairly big structure, with private/reserved fields, it contains another structure (WSAPROTOCOLCHAIN), has fixed-length arrays, GUID, and utf16 string. QAPI'fying that structure back and forth would be tedious and error-prone. Better to treat it as an opaque blob imho. > > > # Returns: Nothing on success > > # > > # Since: 0.14 > > @@ -270,7 +278,11 @@ > > # <- { "return": {} } > > # > > ## > > -{ 'command': 'getfd', 'data': {'fdname': 'str'} } > > +{ 'command': 'getfd', 'data': { > > + 'fdname': 'str', > > + '*wsa-info': {'type': 'str', 'if': 'CONFIG_WIN32'} > > + } > > +} > > What happens when QEMU runs on a Windows host and the client doesn't > pass @wsa-info? It attempts to get the fd from the last recv, but it will fail on Windows, this is not available. -- Marc-André Lureau
