[libvirt] [PATCH] Ensure nodeinfo struct is initialized to zero

[Daniel P. Berrange]

From: "Daniel P. Berrange" <berrange at redhat.com>

When linuxNodeInfoCPUPopulate() method triggered use of an
uninitialize value, since it did not initialize the 'sockets'
field in the virNodeInfoPtr struct:

==30020== Conditional jump or move depends on uninitialised value(s)
==30020==    at 0x5125DBD: linuxNodeInfoCPUPopulate (nodeinfo.c:513)
==30020==    by 0x51261A0: nodeGetInfo (nodeinfo.c:884)
==30020==    by 0x149B9B10: qemuCapsInit (qemu_capabilities.c:846)
==30020==    by 0x14A11B25: qemuCreateCapabilities (qemu_driver.c:424)
==30020==    by 0x14A12426: qemuStartup (qemu_driver.c:874)
==30020==    by 0x512A7AF: virStateInitialize (libvirt.c:822)
==30020==    by 0x40DE04: daemonRunStateInit (libvirtd.c:877)
==30020==    by 0x50ADCE5: virThreadHelper (virthreadpthread.c:161)
==30020==    by 0x328CA07D14: start_thread (pthread_create.c:308)
==30020==    by 0x328C6F246C: clone (clone.S:114)
(happened twice)

        if (socks > nodeinfo->sockets)    <--- here
            nodeinfo->sockets = socks;

Rather than doing this for each field, just make the caller memset
the entire struct to zero.

Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
---
 src/nodeinfo.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/src/nodeinfo.c b/src/nodeinfo.c
index 477104f..5b91a12 100644
--- a/src/nodeinfo.c
+++ b/src/nodeinfo.c
@@ -387,11 +387,6 @@ int linuxNodeInfoCPUPopulate(FILE *cpuinfo,
     char *sysfs_nodedir = NULL;
     char *sysfs_cpudir = NULL;
 
-    nodeinfo->cpus = 0;
-    nodeinfo->mhz = 0;
-    nodeinfo->cores = 0;
-    nodeinfo->nodes = 0;
-
     /* Start with parsing CPU clock speed from /proc/cpuinfo */
     while (fgets(line, sizeof(line), cpuinfo) != NULL) {
 # if defined(__x86_64__) || \
@@ -868,6 +863,8 @@ int nodeGetInfo(virConnectPtr conn ATTRIBUTE_UNUSED, virNodeInfoPtr nodeinfo)
 {
     virArch hostarch = virArchFromHost();
 
+    memset(nodeinfo, 0, sizeof(nodeinfo));
+
     if (virStrcpyStatic(nodeinfo->model, virArchToString(hostarch)) == NULL)
         return -1;
 
-- 
1.8.1