DBus: introduce virDBusIsServiceEnabled

This patch introduces virDBusIsServiceEnabled, we can use
this method to get if the service is supported.

In one case, if org.freedesktop.machine1 is unavailable on
host, we should skip creating machine through systemd.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>

diff --git a/src/util/virdbus.c b/src/util/virdbus.c
index 62c31bea810e64caa990c58d2911e35b2cca53f8..a2c4b4e42deb537ca343d01192bab1eee11f5d0d 100644 (file)
--- a/src/util/virdbus.c
+++ b/src/util/virdbus.c
@@ -1207,6 +1207,61 @@ int virDBusMessageRead(DBusMessage *msg,
     return ret;
 }
 
+/**
+ * virDBusIsServiceEnabled:
+ * @name: service name
+ *
+ * Retruns 0 if service is available, -1 on fatal error, or -2 if service is not available
+ */
+int virDBusIsServiceEnabled(const char *name)
+{
+    DBusConnection *conn;
+    DBusMessage *reply = NULL;
+    DBusMessageIter iter, sub;
+    int ret = -1;
+
+    if (!virDBusHasSystemBus())
+        return -2;
+
+    conn = virDBusGetSystemBus();
+
+    if (virDBusCallMethod(conn,
+                          &reply,
+                          "org.freedesktop.DBus",
+                          "/org/freedesktop/DBus",
+                          "org.freedesktop.DBus",
+                          "ListActivatableNames",
+                          DBUS_TYPE_INVALID) < 0)
+        return ret;
+
+    if (!dbus_message_iter_init(reply, &iter) ||
+        dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_ARRAY) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Reply message incorrect"));
+        goto cleanup;
+    }
+
+    ret = -2;
+    dbus_message_iter_recurse(&iter, &sub);
+    while (dbus_message_iter_get_arg_type(&sub) == DBUS_TYPE_STRING) {
+        const char *service = NULL;
+
+        dbus_message_iter_get_basic(&sub, &service);
+        dbus_message_iter_next(&sub);
+
+        if (STREQ(service, name)) {
+            ret = 0;
+            break;
+        }
+    }
+
+    VIR_DEBUG("Service %s is %s", name, ret ? "unavailable" : "available");
+
+ cleanup:
+    dbus_message_unref(reply);
+    return ret;
+}
+
 
 #else /* ! WITH_DBUS */
 DBusConnection *virDBusGetSystemBus(void)
@@ -1271,4 +1326,10 @@ int virDBusMessageDecode(DBusMessage* msg ATTRIBUTE_UNUSED,
     return -1;
 }
 
+int virDBusIsServiceEnabled(const char *name ATTRIBUTE_UNUSED)
+{
+    VIR_DEBUG("DBus support not compiled into this binary");
+    return -2;
+}
+
 #endif /* ! WITH_DBUS */

diff --git a/src/util/virdbus.h b/src/util/virdbus.h
index a5aab568f65fe4e113fe863d6ac6bb9c94f00ca9..194a01abbad7d9f3fd5d40ec57084fc258e167cf 100644 (file)
--- a/src/util/virdbus.h
+++ b/src/util/virdbus.h
@@ -45,4 +45,5 @@ int virDBusCallMethod(DBusConnection *conn,
 int virDBusMessageRead(DBusMessage *msg,
                        const char *types, ...);
 
+int virDBusIsServiceEnabled(const char *name);
 #endif /* __VIR_DBUS_H__ */

diff --git a/src/util/virsystemd.c b/src/util/virsystemd.c
index 3e69ef66790fd8de00e80f67556645463e3d6975..7674cc6cf9eb35f2d417f25c61c66b1d7ba66882 100644 (file)
--- a/src/util/virsystemd.c
+++ b/src/util/virsystemd.c
@@ -138,18 +138,20 @@ int virSystemdCreateMachine(const char *name,
                             bool iscontainer,
                             const char *partition)
 {
-    int ret = -1;
+    int ret;
     DBusConnection *conn;
     char *machinename = NULL;
     char *creatorname = NULL;
     char *username = NULL;
     char *slicename = NULL;
 
-    if (!virDBusHasSystemBus())
-        return -2;
+    ret = virDBusIsServiceEnabled("org.freedesktop.machine1");
+    if (ret < 0)
+        return ret;
 
     conn = virDBusGetSystemBus();
 
+    ret = -1;
     if (privileged) {
         if (virAsprintf(&machinename, "%s-%s", drivername, name) < 0)
             goto cleanup;
@@ -228,15 +230,8 @@ int virSystemdCreateMachine(const char *name,
                           (unsigned int)pidleader,
                           rootdir ? rootdir : "",
                           1, "Slice", "s",
-                          slicename) < 0) {
-        virErrorPtr err = virGetLastError();
-        if (err->code == VIR_ERR_DBUS_SERVICE &&
-            STREQ(err->str2, "org.freedesktop.DBus.Error.ServiceUnknown")) {
-            virResetLastError();
-            ret = -2;
-        }
+                          slicename) < 0)
         goto cleanup;
-    }
 
     ret = 0;