Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 57 insertions, 0 deletions

diff --git a/util/dbus.c b/util/dbus.c
new file mode 100644
index 000000000..9099dc5b4
--- /dev/null
+++ b/util/dbus.c
@@ -0,0 +1,57 @@
+/*
+ * Helpers for using D-Bus
+ *
+ * Copyright (C) 2019 Red Hat, Inc.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/dbus.h"
+#include "qemu/error-report.h"
+#include "qapi/error.h"
+
+/*
+ * qemu_dbus_get_queued_owners() - return the list of queued unique names
+ * @connection: A GDBusConnection
+ * @name: a service name
+ *
+ * Return: a GStrv of unique names, or NULL on failure.
+ */
+GStrv
+qemu_dbus_get_queued_owners(GDBusConnection *connection, const char *name,
+                            Error **errp)
+{
+    g_autoptr(GDBusProxy) proxy = NULL;
+    g_autoptr(GVariant) result = NULL;
+    g_autoptr(GVariant) child = NULL;
+    g_autoptr(GError) err = NULL;
+
+    proxy = g_dbus_proxy_new_sync(connection, G_DBUS_PROXY_FLAGS_NONE, NULL,
+                                  "org.freedesktop.DBus",
+                                  "/org/freedesktop/DBus",
+                                  "org.freedesktop.DBus",
+                                  NULL, &err);
+    if (!proxy) {
+        error_setg(errp, "Failed to create DBus proxy: %s", err->message);
+        return NULL;
+    }
+
+    result = g_dbus_proxy_call_sync(proxy, "ListQueuedOwners",
+                                    g_variant_new("(s)", name),
+                                    G_DBUS_CALL_FLAGS_NO_AUTO_START,
+                                    -1, NULL, &err);
+    if (!result) {
+        if (g_error_matches(err,
+                            G_DBUS_ERROR,
+                            G_DBUS_ERROR_NAME_HAS_NO_OWNER)) {
+            return g_new0(char *, 1);
+        }
+        error_setg(errp, "Failed to call ListQueuedOwners: %s", err->message);
+        return NULL;
+    }
+
+    child = g_variant_get_child_value(result, 0);
+    return g_variant_dup_strv(child, NULL);
+}