block: Check create_opts before image creation

If a driver supports image creation, it needs to set the .create_opts field. We can use that to make sure .create_opts for both drivers involved is not NULL in bdrv_img_create(), which is important so that the create_opts pointer in that function is not NULL after the qemu_opts_append() calls and when going into qemu_opts_create(). Cc: [email protected] Signed-off-by: Max Reitz <[email protected]> Reviewed-by: Kevin Wolf <[email protected]> Signed-off-by: Kevin Wolf <[email protected]>
amazonsx · Dec 10, 2014 · c614972 · c614972
1 parent fd75280
commit c614972
Showing 1 changed file with 12 additions and 0 deletions.
diff --git a/block.c b/block.c
@@ -5569,6 +5569,18 @@ void bdrv_img_create(const char *filename, const char *fmt,
         return;
     }
 
+    if (!drv->create_opts) {
+        error_setg(errp, "Format driver '%s' does not support image creation",
+                   drv->format_name);
+        return;
+    }
+
+    if (!proto_drv->create_opts) {
+        error_setg(errp, "Protocol driver '%s' does not support image creation",
+                   proto_drv->format_name);
+        return;
+    }
+
     create_opts = qemu_opts_append(create_opts, drv->create_opts);
     create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);