On Wed, Nov 30, 2011 at 02:51:06PM +0100, Christophe Fergeau wrote:
> This method starts by looking up a domain in priv->domains, and later,
> depending on the kind of event that occurred, it may remove this
> domain from priv->domains. While the individual operations (lookup,
> removal) are protected by priv->lock, there is no guarantee that the
> looked up domain and even priv->domains will stay unchanged when
> priv->lock isn't held.
>
> In particular, gvir_connection_close will destroy priv->domains which
> will unreference all the domains it contains (potentially destroying
> them too), and gvir_connection_fetch_domains will change priv->domains
> value.
>
> To avoid these issues, this commit takes a reference on priv->domains
> so that it doesn't get away behind our back, and it takes a reference
> on the looked up domain too to ensure it stays alive for the duration
> of domain_event_cb run.
> ---
> libvirt-gobject/libvirt-gobject-connection.c | 17 +++++++++++------
> 1 files changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/libvirt-gobject/libvirt-gobject-connection.c b/libvirt-gobject/libvirt-gobject-connection.c
> index 59b828d..786a026 100644
> --- a/libvirt-gobject/libvirt-gobject-connection.c
> +++ b/libvirt-gobject/libvirt-gobject-connection.c
> @@ -257,6 +257,7 @@ static int domain_event_cb(virConnectPtr conn G_GNUC_UNUSED,
> void *opaque)
> {
> gchar uuid[VIR_UUID_STRING_BUFLEN];
> + GHashTable *doms;
> GVirConnection *gconn = opaque;
> GVirDomain *gdom;
> GVirConnectionPrivate *priv = gconn->priv;
> @@ -269,14 +270,18 @@ static int domain_event_cb(virConnectPtr conn G_GNUC_UNUSED,
> g_debug("%s: %s event:%d, detail:%d", G_STRFUNC, uuid, event, detail);
>
> g_mutex_lock(priv->lock);
> - gdom = g_hash_table_lookup(priv->domains, uuid);
> + doms = g_hash_table_ref(priv->domains);
> + gdom = g_hash_table_lookup(doms, uuid);
> + if (gdom != NULL)
> + g_object_ref(G_OBJECT(gdom));
> g_mutex_unlock(priv->lock);
>
> if (gdom == NULL) {
> gdom = GVIR_DOMAIN(g_object_new(GVIR_TYPE_DOMAIN, "handle", dom, NULL));
>
> g_mutex_lock(priv->lock);
> - g_hash_table_insert(priv->domains, (gpointer)gvir_domain_get_uuid(gdom), gdom);
> + g_hash_table_insert(doms, (gpointer)gvir_domain_get_uuid(gdom),
> + g_object_ref(G_OBJECT(gdom)));
> g_mutex_unlock(priv->lock);
> }
>
> @@ -293,11 +298,10 @@ static int domain_event_cb(virConnectPtr conn G_GNUC_UNUSED,
> case VIR_DOMAIN_EVENT_UNDEFINED:
> if (detail == VIR_DOMAIN_EVENT_UNDEFINED_REMOVED) {
> g_mutex_lock(priv->lock);
> - g_hash_table_steal(priv->domains, uuid);
> + g_hash_table_remove(doms, uuid);
> g_mutex_unlock(priv->lock);
>
> g_signal_emit(gconn, signals[VIR_DOMAIN_REMOVED], 0, gdom);
> - g_object_unref(gdom);
> } else
> g_warn_if_reached();
> break;
> @@ -365,11 +369,10 @@ static int domain_event_cb(virConnectPtr conn G_GNUC_UNUSED,
>
> if (virDomainIsPersistent(dom) != 1) {
> g_mutex_lock(priv->lock);
> - g_hash_table_steal(priv->domains, uuid);
> + g_hash_table_remove(doms, uuid);
> g_mutex_unlock(priv->lock);
>
> g_signal_emit(gconn, signals[VIR_DOMAIN_REMOVED], 0, gdom);
> - g_object_unref(gdom);
> }
> break;
>
> @@ -377,6 +380,8 @@ static int domain_event_cb(virConnectPtr conn G_GNUC_UNUSED,
> g_warn_if_reached();
> }
>
> + g_object_unref(G_OBJECT(gdom));
> + g_hash_table_unref(doms);
> return 0;
> }
ACK
Daniel
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