From: Michal Privoznik <mprivozn@redhat.com>
Date: Tue, 17 Apr 2018 15:52:03 +0000 (+0200)
Subject: virobject: Check if @parent is the first member in class
X-Git-Tag: v4.3.0-rc1~185
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=76ae74b1d16260c56b65a2764498b4601ada06e0;p=thirdparty%2Flibvirt.git

virobject: Check if @parent is the first member in class

Our virObject code relies heavily on the fact that the first
member of the class struct is type of virObject (or some
derivation of if). Let's check for that.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
---

diff --git a/src/util/virobject.h b/src/util/virobject.h
index ed1a117b09..77ebad1e8b 100644
--- a/src/util/virobject.h
+++ b/src/util/virobject.h
@@ -76,7 +76,8 @@ virClassPtr virClassForObjectRWLockable(void);
 # endif
 
 # define VIR_CLASS_NEW(name, prnt) \
-    (name##Class = virClassNew(prnt, #name, sizeof(name), name##Dispose))
+    verify_expr(offsetof(name, parent) == 0, \
+      (name##Class = virClassNew(prnt, #name, sizeof(name), name##Dispose)))
 
 virClassPtr
 virClassNew(virClassPtr parent,