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

Lukas Venhoda lvenhoda at redhat.com
Thu Sep 17 05:29:21 PDT 2015


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."


>
> 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
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