Re: [libvirt] [PATCH 1/4] Make avahi startup more robust.

21 Apr 2010


      On 04/21/2010 10:03 AM, Chris Lalancette wrote:
...
If the hostname of the current virtualization machine
could not be resolved, then libvirtd would fail to
start.  However, for disconnected operation (on a laptop,
for instance) the hostname may very legitimately not
be resolvable.  This patch makes it so that if we can't
resolve the hostname, avahi doesn't fail, it just uses
a less useful MDNS string.
ACK on the concept, but fix the corner-case memory leak before pushing.
...
if (!mdns_name) {
-            char groupname[64], *localhost, *tmp;
+            char *groupname, *localhost, *tmp;
             /* Extract the host part of the potentially FQDN */
             localhost = virGetHostname(NULL);
Here, localhost can be allocated...
...
if (localhost == NULL)
+                ret = virAsprintf(&groupname, "Virtualization Host");
+            else {
+                if ((tmp = strchr(localhost, '.')))
+                    *tmp = '\0';
+                ret = virAsprintf(&groupname, "Virtualization Host %s",
+                                  localhost);
then groupname fails...
...
+            }
+            if (ret < 0) {
+                virReportOOMError();
                 goto cleanup;
...and we leak localhost.
...
-
-            if ((tmp = strchr(localhost, '.')))
-                *tmp = '\0';
-            snprintf(groupname, sizeof(groupname)-1, "Virtualization Host %s", localhost);
-            groupname[sizeof(groupname)-1] = '\0';
+            }
             group = libvirtd_mdns_add_group(server->mdns, groupname);
             VIR_FREE(localhost);
+            VIR_FREE(groupname);
But on success, there is no leak.

-- 
Eric Blake   eblake@redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org