Ensure remote daemon unions are always non-zero length

If the remote daemon args/ret unions ever become zero length
(due to a build / Makefile bug) then bad stuff happens at
runtime. Add a compile time assertion to check for this kind
of problem

* daemon/remote.h: Ensure non-zero length unions

diff --git a/daemon/remote.h b/daemon/remote.h
index fd8d3814a87142a315aa04a6e85961293f1ca851..1eb83865cb8da8e1ab4093104238be2c81e0eb09 100644 (file)
--- a/daemon/remote.h
+++ b/daemon/remote.h
@@ -30,18 +30,22 @@
 typedef union {
 # include "remote_dispatch_args.h"
 } dispatch_args;
+verify(sizeof(dispatch_args) > 0);
 
 typedef union {
 # include "remote_dispatch_ret.h"
 } dispatch_ret;
+verify(sizeof(dispatch_ret) > 0);
 
 typedef union {
 # include "qemu_dispatch_args.h"
 } qemu_dispatch_args;
+verify(sizeof(qemu_dispatch_args) > 0);
 
 typedef union {
 # include "qemu_dispatch_ret.h"
 } qemu_dispatch_ret;
+verify(sizeof(qemu_dispatch_ret) > 0);