[Qemu-stable] [PATCH 04/12] block: Check create_opts before image creation

[Max Reitz]

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: address@hidden
Signed-off-by: Max Reitz <address@hidden>
---
 block.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/block.c b/block.c
index b31fb67..1e4a72f 100644
--- a/block.c
+++ b/block.c
@@ -5560,6 +5560,18 @@ 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);
 
-- 
1.9.3