[Spice-devel] [phodav PATCH 4/4] spice-webdavd: Automount shared folder on Windows

[Victor Toso]

Hey,

On Thu, Sep 17, 2015 at 02:29:21PM +0200, Lukas Venhoda wrote:
> Hi
> 
> On Thu, Sep 17, 2015 at 12:23 PM, Marc-André Lureau <
> marcandre.lureau at gmail.com> wrote:
> 
> > Hi
> >
> > On Thu, Aug 27, 2015 at 6:25 PM, Lukas Venhoda <lvenhoda at redhat.com>
> > wrote:
> > > Try to connect to shared folder automatically on Windows.
> > >
> > > On each loop of run_service(), spawn a thread, that waits for 5 seconds.
> > > If read_thread() returns, it means, that sharing is not yet connected,
> > > and the map_drive thread is cancelled, and joined back to main thread.
> > >
> > > If the map_drive thread is NOT cancelled, it enumerates free drive
> > > letters, and maps shared folder to highest possible (from Z: to A:).
> > >
> > > If all drive letters are already assigned, stop the service.
> >
> > Could you explain in the commit message why you need the thread ?
> >
>
> How about this commit message?
>
> "Try to connect to shared folder automatically on Windows.
>
> When client is connected, and sharing is enabled, map_drive is called.
> It enumerates free drive letters, and maps shared folder to highest
> possible,
> from (Z:) to (A:). If all drive letters are already assigned, stops the
> service.
>
> map_drive needs to be called only after, the read_thread blocks.
> If it is called before, the mapping fails.
>
> In order to call it only after read_thread blocks, we spawn a thread,
> that waits for 5 seconds, before actually calling map_drive.
> If read_thread() returns, it means, that sharing is not yet connected,
> and the map_drive thread is cancelled.
>
> We spawn this thread on each loop of run_service(), and join it back
> into main_thread, after main loop ends."
>

I would also include that this patch resolves
https://bugs.freedesktop.org/show_bug.cgi?id=90477

- toso
>
> >
> > How do you prevent from having multiple drive pointing to the spice folder?
> >
> >
> Currently, I don't.
> 
> Only way to connect multiple drives, is if you restart the service,
> because the drives will disconnect, after restarting guest.
> 
> I will add a disconnect function to the quit function in the service,
> so that if uou disable, or restart teh service, the drive will be unmapped
> 
> 
> >
> > > ---
> > > Changes since RFC:
> > >  - Calling WNetAddConnection2() blindly was slow and caause many threads
> > to spawn.
> > >     - Now only call it once, when it is sure, that it will connect.
> > >  - Now connects to a * drive, instead of always Z:
> > >  - Thread is now spawned and joined every time run_service() is called.
> > > ---
> > >  Makefile.am           |  4 +++
> > >  spice/spice-webdavd.c | 76
> > +++++++++++++++++++++++++++++++++++++++++++++++++++
> > >  2 files changed, 80 insertions(+)
> > >
> > > diff --git a/Makefile.am b/Makefile.am
> > > index 485417b..df9a73e 100644
> > > --- a/Makefile.am
> > > +++ b/Makefile.am
> > > @@ -87,6 +87,10 @@ spice_webdavd_LDADD =                \
> > >         $(PIE_LDFLAGS)          \
> > >         $(NULL)
> > >
> > > +if OS_WIN32
> > > +spice_webdavd_LDADD += -lnetapi32 -lmpr
> > > +endif
> > > +
> > >  deps.txt:
> > >         $(AM_V_GEN)rpm -qa | grep $(host_os) | sort | unix2dos > $@
> > >
> > > diff --git a/spice/spice-webdavd.c b/spice/spice-webdavd.c
> > > index f9c5cf1..3940f1c 100644
> > > --- a/spice/spice-webdavd.c
> > > +++ b/spice/spice-webdavd.c
> > > @@ -737,11 +737,81 @@ open_mux_path (const char *path)
> > >    mux_queue = output_queue_new (G_OUTPUT_STREAM (mux_ostream));
> > >  }
> > >
> > > +#ifdef G_OS_WIN32
> > > +static gchar
> > > +get_free_drive_letter(void)
> > > +{
> > > +  const guint32 max_mask = 1 << 25;
> > > +  guint32 drives;
> > > +  guint32 mask;
> > > +  gint i;
> > > +
> > > +  drives = GetLogicalDrives ();
> > > +
> > > +  for (i = 0; i < 26; i++)
> > > +    {
> > > +      mask = max_mask >> i;
> > > +      if ((drives & mask) == 0)
> > > +        return 'Z' - i;
> > > +    }
> > > +
> > > +  return 0;
> > > +}
> > > +
> > > +static gpointer
> > > +map_drive(gpointer user_data)
> > > +{
> > > +  GCancellable * cancel_map = user_data;
> > > +  gchar drive_letter;
> > > +  gchar local_name[3];
> > > +  gchar remote_name[] = "http://localhost:9843/";
> > > +  NETRESOURCE net_resource;
> > > +  guint32 retval;
> > > +  gint i;
> > > +
> > > +  for (i = 0; i < 5; ++i)
> > > +    {
> > > +      if (g_cancellable_is_cancelled (cancel_map))
> > > +        return NULL;
> > > +      else
> > > +        g_usleep (G_USEC_PER_SEC);
> > > +    }
> >
> > It looks like this would fail if the guest is started without client
> > connected (or not sharing folder).
> >
> 
> I'm not sure I follow.
> This is supposed to return NULL precisely, if the client is not connected,
> or not sharing folder. Windows webdavd will loop and call run_service(),
> until sharing is enabled, which will then NOT cancel this function,
> and we map the drive.
> 
> 
> >
> > > +
> > > +  if ((drive_letter = get_free_drive_letter ()) == 0)
> > > +      g_error ("all drive letters already assigned.");
> > > +
> > > +  local_name[0] = drive_letter;
> > > +  local_name[1] = ':';
> > > +  local_name[2] = 0;
> > > +
> > > +  net_resource.dwType = RESOURCETYPE_DISK;
> > > +  net_resource.lpLocalName = local_name;
> > > +  net_resource.lpRemoteName = remote_name;
> > > +  net_resource.lpProvider = NULL;
> > > +
> > > +  retval = WNetAddConnection2 (&net_resource, NULL, NULL,
> > CONNECT_TEMPORARY);
> > > +
> > > +  if (retval == NO_ERROR)
> > > +    g_debug ("map_drive ok");
> > > +  else if (retval == ERROR_ALREADY_ASSIGNED)
> > > +    g_debug ("map_drive already asigned");
> > > +  else
> > > +    g_error ("map_drive error %d", retval);
> > > +
> > > +  return NULL;
> > > +}
> > > +#endif
> > > +
> > >  static void
> > >  run_service (void)
> > >  {
> > >    g_debug ("Run service");
> > >
> > > +#ifdef G_OS_WIN32
> > > +  GCancellable * cancel_map = g_cancellable_new ();
> > > +  GThread * map_drive_thread = g_thread_new ("map-drive-thread",
> > map_drive, cancel_map);
> > > +#endif
> > > +
> > >    g_socket_service_start (socket_service);
> > >
> > >    cancel = g_cancellable_new ();
> > > @@ -775,6 +845,12 @@ run_service (void)
> > >    g_main_loop_run (loop);
> > >    g_main_loop_unref (loop);
> > >
> > > +#ifdef G_OS_WIN32
> > > +  g_cancellable_cancel (cancel_map);
> > > +  g_thread_join(map_drive_thread);
> > > +  g_print ("map-drive-thread joined\n");
> > > +#endif
> > > +
> > >    g_cancellable_cancel (cancel);
> > >
> > >    g_clear_object (&mux_istream);
> > > --
> > > 2.4.3
> > >
> > > _______________________________________________
> > > Spice-devel mailing list
> > > Spice-devel at lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/spice-devel
> >
> >
> >
> > --
> > Marc-André Lureau
> >
> 
> Lukas Venhoda

> _______________________________________________
> Spice-devel mailing list
> Spice-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/spice-devel