convert: Crash fixing while using camera

Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

zbar/convert.c

@@ -1125,32 +1125,36 @@ int _zbar_best_format(uint32_t src, uint32_t *dst, const uint32_t *dsts)
 
 int zbar_negotiate_format(zbar_video_t *vdo, zbar_window_t *win)
 {
+    static const uint32_t y800[2] = { fourcc('Y','8','0','0'), 0 };
     errinfo_t *errdst;
     const uint32_t *srcs, *dsts;
     unsigned min_cost = -1;
     uint32_t min_fmt  = 0;
     const uint32_t *fmt;
 
-    if (!vdo && !win)
+    if (!vdo)
 	return (0);
 
-    (void)window_lock(win);
+    if (win)
+	(void)window_lock(win);
 
     errdst = &vdo->err;
     if (verify_format_sort()) {
-	(void)window_unlock(win);
+	if (win)
+	    (void)window_unlock(win);
 	return (err_capture(errdst, SEV_FATAL, ZBAR_ERR_INTERNAL, __func__,
 			    "image format list is not sorted!?"));
     }
 
-    if (!vdo->format || !win->formats) {
-	(void)window_unlock(win);
+    if (!vdo->formats || (win && !win->formats)) {
+	if (win)
+	    (void)window_unlock(win);
 	return (err_capture(errdst, SEV_ERROR, ZBAR_ERR_UNSUPPORTED, __func__,
 			    "no input or output formats available"));
     }
 
     srcs = vdo->formats;
-    dsts = win->formats;
+    dsts = (win) ? win->formats : y800;
 
     for (fmt = _zbar_formats; *fmt; fmt++) {
 	/* only consider formats supported by video device */
@@ -1180,7 +1184,7 @@ int zbar_negotiate_format(zbar_video_t *vdo, zbar_window_t *win)
 	vdo->emu_formats = NULL;
 
 	srcs = vdo->formats;
-	dsts = win->formats;
+	dsts = (win) ? win->formats : y800;
 
 	/*
         * Use the same cost algorithm to select emulated formats.
@@ -1212,7 +1216,8 @@ int zbar_negotiate_format(zbar_video_t *vdo, zbar_window_t *win)
 	}
     }
 
-    (void)window_unlock(win);
+    if (win)
+	(void)window_unlock(win);
 
     if (!min_fmt)
 	return (err_capture(errdst, SEV_ERROR, ZBAR_ERR_UNSUPPORTED, __func__,