[libvirt] [libvirt-glib][PATCH v3 1/2] gobject: Introduce gvir_connection_get_hypervisor_name
Michal Privoznik
mprivozn at redhat.com
Wed Sep 12 16:53:11 UTC 2012
On 12.09.2012 17:54, Christophe Fergeau wrote:
> On Wed, Sep 12, 2012 at 05:32:00PM +0200, Michal Privoznik wrote:
>> which is basically a wrapper for virConnectGetType().
>> ---
>>
>> The list is sad as it hasn't delivered previous version.
>>
>> examples/conn-test.c | 12 +++++++
>> libvirt-gobject/libvirt-gobject-connection.c | 45 ++++++++++++++++++++++++++
>> libvirt-gobject/libvirt-gobject-connection.h | 3 ++
>> libvirt-gobject/libvirt-gobject.sym | 5 +++
>> 4 files changed, 65 insertions(+), 0 deletions(-)
>>
>> diff --git a/examples/conn-test.c b/examples/conn-test.c
>> index 8c70997..b90d2b0 100644
>> --- a/examples/conn-test.c
>> +++ b/examples/conn-test.c
>> @@ -31,11 +31,23 @@ do_connection_open(GObject *source,
>> {
>> GVirConnection *conn = GVIR_CONNECTION(source);
>> GError *err = NULL;
>> + gchar *hv_name = NULL;
>>
>> if (!gvir_connection_open_finish(conn, res, &err)) {
>> g_error("%s", err->message);
>> + goto cleanup;
>
> g_error() calls abort(), so this goto cleanup; is not really useful
>
>> }
>> g_print("Connected to libvirt\n");
>> +
>> + if (!(hv_name = gvir_connection_get_hypervisor_name(conn, &err))) {
>> + g_error("%s", err->message);
>> + goto cleanup;
>> + }
>> +
>> + g_print("Hypervisor name: %s\n", hv_name);
>> +
>> +cleanup:
>> + g_free(hv_name);
>> g_object_unref(conn);
>> }
>>
>> diff --git a/libvirt-gobject/libvirt-gobject-connection.c b/libvirt-gobject/libvirt-gobject-connection.c
>> index d826905..75bf041 100644
>> --- a/libvirt-gobject/libvirt-gobject-connection.c
>> +++ b/libvirt-gobject/libvirt-gobject-connection.c
>> @@ -1025,6 +1025,51 @@ const gchar *gvir_connection_get_uri(GVirConnection *conn)
>> return conn->priv->uri;
>> }
>>
>> +/**
>> + * gvir_connection_get_hypervisor_name:
>> + * @conn: a #GVirConnection
>> + * @err: return location for any #GError
>> + *
>> + * Get name of current hypervisor used.
>> + *
>> + * Return value: new string that should be freed when no longer needed,
>> + * or NULL upon error.
>> + */
>> +gchar *
>> +gvir_connection_get_hypervisor_name(GVirConnection *conn,
>> + GError **err)
>> +{
>> + GVirConnectionPrivate *priv;
>> + gchar *ret = NULL;
>> + const char *type;
>> +
>> + g_return_val_if_fail(GVIR_IS_CONNECTION(conn), NULL);
>> + g_return_val_if_fail(err == NULL || *err == NULL, NULL);
>> +
>> + priv = conn->priv;
>> + /* Stop another thread closing the connection just at the minute */
>> + virConnectRef(priv->conn);
>
> I'm not sure what this achieves? Another thread could close priv->conn
> right before this call, so why ref it just now? Do calls to
> virConnectGetType need to be protected with a ref?
I though it would be nice to have a reference counter increased through
this API so other thread don't close it right in the middle.
But now as I am rethinking this again - it is already done on libvirt level.
IOW in a racy situation it just make this API more probable to fetch
result. It depends if the last virConnectClose() is scheduled before of
after virConnectRef().
So yeah, I should have dropped it. Fixed on my local branch now.
Michal
>
>
>> + if (!priv->conn) {
>> + g_set_error_literal(err, GVIR_CONNECTION_ERROR, 0,
>> + "Connection is not open");
>
> opened
>
> Christophe
>
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