[vdr] OSD "ERROR: attempt to open OSD while it is already open!"

[Nicolas Huillard <nhuillard@ghs.fr>]

Hi,

When using femon to change channel to a encrypted one, with no CA 
available, VDR tries to show the "Channel unavailable" message, while 
the OSD is still tied to femon... crash...

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 16384 (LWP 30703)]
0x080cfd40 in cSkinSTTNGDisplayMessage::cSkinSTTNGDisplayMessage ()
(gdb) bt
#0  0x080cfd40 in cSkinSTTNGDisplayMessage::cSkinSTTNGDisplayMessage ()
#1  0x080d02a2 in cSkinSTTNG::DisplayMessage ()
#2  0x080c9c96 in cSkins::Message ()
#3  0x080883dd in cDevice::SwitchChannel ()
#4  0x0807e281 in cChannels::SwitchTo ()
#5  0x408aff40 in cFemonOsd::ProcessKey () from 
/usr/lib/vdr/plugins/libvdr-femon.so.1.3.12
#6  0x080ddd76 in main ()
(gdb)

I traces it back to 
cSkinSTTNGDisplayMessage::cSkinSTTNGDisplayMessage(void) in "skinsttng.c" :

    854   osd = cOsdProvider::NewOsd(Setup.OSDLeft, Setup.OSDTop + 
Setup.OSDHeight - y1);
    855   tArea Areas[] = { { x0, y0, x7 - 1, y1 - 1, 2 } };
    856   osd->SetAreas(Areas, sizeof(Areas) / sizeof(tArea));

Since cOsdProvider::NewOsd() can return NULL, osd->anything shouldn't be 
called without testing.
I simply cannot decide how to handle the case, since we are in the 
constructor cSkinSTTNGDisplayMessage::cSkinSTTNGDisplayMessage and many 
methods after that will try to use the osd property, and crash... The 
cSkinSTTNGDisplayMessage should simply abort it's construction, but I 
don't know how to write it in C++...

--
NH