Re: [PATCH v4 08/11] qmp: add 'get-win32-socket'

[Marc-André Lureau]

Hi

On Mon, Mar 6, 2023 at 7:49 PM Markus Armbruster <armbru@redhat.com> wrote:
>
> marcandre.lureau@redhat.com writes:
>
> > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> >
> > A process with enough capabilities can duplicate a socket to QEMU. Add a
> > QMP command to import it and add it to the monitor fd list, so it can be
> > later used by other commands.
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >  qapi/misc.json | 30 ++++++++++++++++++++
> >  monitor/fds.c  | 76 +++++++++++++++++++++++++++++++++++++++-----------
> >  2 files changed, 90 insertions(+), 16 deletions(-)
> >
> > diff --git a/qapi/misc.json b/qapi/misc.json
> > index f0217cfba0..031c94050c 100644
> > --- a/qapi/misc.json
> > +++ b/qapi/misc.json
> > @@ -275,6 +275,36 @@
> >  ##
> >  { 'command': 'getfd', 'data': {'fdname': 'str'} }
> >
> > +##
> > +# @get-win32-socket:
> > +#
> > +# Add a socket that was duplicated to QEMU process with 
> > WSADuplicateSocketW()
> > +# via WSASocket() & WSAPROTOCOL_INFOW structure and assign it a name (the 
> > SOCKET
> > +# is associated with a CRT file descriptor)
>
> Long line.
>

Ok.. see related .editorconfig patch to make everyone's life easier.

> > +#
> > +# @info: the WSAPROTOCOL_INFOW structure (encoded in base64)
> > +#
> > +# @fdname: file descriptor name
> > +#
> > +# Returns: Nothing on success
> > +#
> > +# Since: 8.0
> > +#
> > +# Notes: If @fdname already exists, the file descriptor assigned to
> > +#        it will be closed and replaced by the received file
> > +#        descriptor.
> > +#
> > +#        The 'closefd' command can be used to explicitly close the
> > +#        file descriptor when it is no longer needed.
> > +#
> > +# Example:
> > +#
> > +# -> { "execute": "get-win32-socket", "arguments": { "info": "abcd123..", 
> > fdname": "skclient" } }
> > +# <- { "return": {} }
> > +#
> > +##
> > +{ 'command': 'get-win32-socket', 'data': {'info': 'str', 'fdname': 'str'}, 
> > 'if': 'CONFIG_WIN32' }
> > +
> >  ##
> >  # @closefd:
> >  #
> > diff --git a/monitor/fds.c b/monitor/fds.c
> > index 7daf1064e1..9ed4197358 100644
> > --- a/monitor/fds.c
> > +++ b/monitor/fds.c
> > @@ -61,46 +61,55 @@ struct MonFdset {
> >  static QemuMutex mon_fdsets_lock;
> >  static QLIST_HEAD(, MonFdset) mon_fdsets;
> >
> > -void qmp_getfd(const char *fdname, Error **errp)
> > +static bool monitor_add_fd(Monitor *mon, int fd, const char *fdname, Error 
> > **errp)
> >  {
> > -    Monitor *cur_mon = monitor_cur();
> >      mon_fd_t *monfd;
> > -    int fd, tmp_fd;
> > -
> > -    fd = qemu_chr_fe_get_msgfd(&cur_mon->chr);
> > -    if (fd == -1) {
> > -        error_setg(errp, "No file descriptor supplied via SCM_RIGHTS");
> > -        return;
> > -    }
> >
> >      if (qemu_isdigit(fdname[0])) {
> >          close(fd);
> >          error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "fdname",
> >                     "a name not starting with a digit");
> > -        return;
> > +        return false;
> >      }
> >
> >      /* See close() call below. */
> > -    qemu_mutex_lock(&cur_mon->mon_lock);
> > -    QLIST_FOREACH(monfd, &cur_mon->fds, next) {
> > +    qemu_mutex_lock(&mon->mon_lock);
> > +    QLIST_FOREACH(monfd, &mon->fds, next) {
> > +        int tmp_fd;
> > +
> >          if (strcmp(monfd->name, fdname) != 0) {
> >              continue;
> >          }
> >
> >          tmp_fd = monfd->fd;
> >          monfd->fd = fd;
> > -        qemu_mutex_unlock(&cur_mon->mon_lock);
> > +        qemu_mutex_unlock(&mon->mon_lock);
> >          /* Make sure close() is outside critical section */
> >          close(tmp_fd);
> > -        return;
> > +        return true;
> >      }
>
> Have you considered factoring out the loop searching ->fds?

Not really, it doesn't look trivial at first sight because they do
different things.

>
> >
> >      monfd = g_new0(mon_fd_t, 1);
> >      monfd->name = g_strdup(fdname);
> >      monfd->fd = fd;
> >
> > -    QLIST_INSERT_HEAD(&cur_mon->fds, monfd, next);
> > -    qemu_mutex_unlock(&cur_mon->mon_lock);
> > +    QLIST_INSERT_HEAD(&mon->fds, monfd, next);
> > +    qemu_mutex_unlock(&mon->mon_lock);
> > +    return true;
> > +}
> > +
> > +void qmp_getfd(const char *fdname, Error **errp)
> > +{
> > +    Monitor *cur_mon = monitor_cur();
> > +    int fd;
> > +
> > +    fd = qemu_chr_fe_get_msgfd(&cur_mon->chr);
> > +    if (fd == -1) {
> > +        error_setg(errp, "No file descriptor supplied via SCM_RIGHTS");
> > +        return;
> > +    }
> > +
> > +    monitor_add_fd(cur_mon, fd, fdname, errp);
> >  }
> >
> >  void qmp_closefd(const char *fdname, Error **errp)
> > @@ -214,6 +223,41 @@ error:
> >      return NULL;
> >  }
>
> With the doc comment tidied up:
> Acked-by: Markus Armbruster <armbru@redhat.com>
>
> The remainder is greek to me :)

ok, thanks

>
> >
> > +#ifdef WIN32
> > +void qmp_get_win32_socket(const char *infos, const char *fdname, Error 
> > **errp)
> > +{
> > +    g_autofree WSAPROTOCOL_INFOW *info = NULL;
> > +    gsize len;
> > +    SOCKET sk;
> > +    int fd;
> > +
> > +    info = (void *)g_base64_decode(infos, &len);
> > +    if (len != sizeof(*info)) {
> > +        error_setg(errp, "Invalid WSAPROTOCOL_INFOW value");
> > +        return;
> > +    }
> > +
> > +    sk = WSASocketW(FROM_PROTOCOL_INFO,
> > +                    FROM_PROTOCOL_INFO,
> > +                    FROM_PROTOCOL_INFO,
> > +                    info, 0, 0);
> > +    if (sk == INVALID_SOCKET) {
> > +        error_setg_win32(errp, WSAGetLastError(), "Couldn't import 
> > socket");
> > +        return;
> > +    }
> > +
> > +    fd = _open_osfhandle(sk, _O_BINARY);
> > +    if (fd < 0) {
> > +        error_setg_errno(errp, errno, "Failed to associate a FD with the 
> > SOCKET");
> > +        closesocket(sk);
> > +        return;
> > +    }
> > +
> > +    monitor_add_fd(monitor_cur(), fd, fdname, errp);
> > +}
> > +#endif
> > +
> > +
> >  void qmp_remove_fd(int64_t fdset_id, bool has_fd, int64_t fd, Error **errp)
> >  {
> >      MonFdset *mon_fdset;
>
>


-- 
Marc-André Lureau