[libvirt] [PATCH] xen_hypervisor.c: avoid NULL deref for NULL domain argument

[Jim Meyering]

When "domain" is NULL, don't deref NULL.  Instead, just return -1,
as in many other functions in this file, and as this function did
up until a month ago.

An alternative (taken 3 times in this file) is to do this:

        virXenErrorFunc (NULL, VIR_ERR_INTERNAL_ERROR, __FUNCTION__,
                         "domain or conn is NULL", 0);
        return -1;

I could go either way.


>From 177556167775b806a29bcb1af7ba4294d1909912 Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering at redhat.com>
Date: Tue, 26 Jan 2010 20:17:07 +0100
Subject: [PATCH] xen_hypervisor.c: avoid NULL deref for NULL domain argument

* src/xen/xen_hypervisor.c (xenHypervisorGetVcpus): Don't attempt
to diagnose an unlikely NULL-domain or NULL-domain->conn error.
---
 src/xen/xen_hypervisor.c |    7 ++-----
 1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/src/xen/xen_hypervisor.c b/src/xen/xen_hypervisor.c
index 6d8accc..0257be2 100644
--- a/src/xen/xen_hypervisor.c
+++ b/src/xen/xen_hypervisor.c
@@ -1,7 +1,7 @@
 /*
  * xen_internal.c: direct access to Xen hypervisor level
  *
- * Copyright (C) 2005, 2006, 2007, 2008, 2009 Red Hat, Inc.
+ * Copyright (C) 2005-2010 Red Hat, Inc.
  *
  * See COPYING.LIB for the License of this software
  *
@@ -3475,11 +3475,8 @@ xenHypervisorGetVcpus(virDomainPtr domain, virVcpuInfoPtr info, int maxinfo,
     virVcpuInfoPtr ipt;
     int nbinfo, i;

-    if (domain == NULL || domain->conn == NULL) {
-        virXenErrorFunc (domain->conn, VIR_ERR_INVALID_ARG, __FUNCTION__,
-                        "invalid argument", 0);
+    if (domain == NULL || domain->conn == NULL)
         return -1;
-    }

     priv = (xenUnifiedPrivatePtr) domain->conn->privateData;
     if (priv->handle < 0 || (domain->id < 0) ||
--
1.7.0.rc0.140.gfbe7