diff --git a/src/networkd.c b/src/networkd.c
index 96ca082b5..7b4ed196e 100644
--- a/src/networkd.c
+++ b/src/networkd.c
@@ -42,11 +42,11 @@ _netplan_sysfs_get_mac_by_ifname(const char* ifname, const char* rootdir)
 {
     g_autofree gchar* content = NULL;
     g_autofree gchar* sysfs_path = NULL;
-    sysfs_path = g_build_path(G_DIR_SEPARATOR_S, rootdir ?: G_DIR_SEPARATOR_S,
+    sysfs_path = g_build_path(G_DIR_SEPARATOR_S, !!rootdir ? rootdir : G_DIR_SEPARATOR_S,
                               "sys", "class", "net", ifname, "address", NULL);
 
     if (!g_file_get_contents (sysfs_path, &content, NULL, NULL)) {
-        g_debug("%s: Cannot read file contents.", __FUNCTION__);
+        g_debug("%s: Cannot read file contents.", __func__);
         return NULL;
     }
 
@@ -63,12 +63,12 @@ _netplan_sysfs_get_driver_by_ifname(const char* ifname, const char* rootdir)
 {
     g_autofree gchar* link = NULL;
     g_autofree gchar* sysfs_path = NULL;
-    sysfs_path = g_build_path(G_DIR_SEPARATOR_S, rootdir ?: G_DIR_SEPARATOR_S,
+    sysfs_path = g_build_path(G_DIR_SEPARATOR_S, !!rootdir ? rootdir : G_DIR_SEPARATOR_S,
                               "sys", "class", "net", ifname, "device", "driver", NULL);
 
     link = g_file_read_link(sysfs_path, NULL);
     if (!link) {
-        g_debug("%s: Cannot read symlink of %s.", __FUNCTION__, sysfs_path);
+        g_debug("%s: Cannot read symlink of %s.", __func__, sysfs_path);
         return NULL;
     }
 
@@ -394,7 +394,8 @@ write_regdom(const NetplanNetDefinition* def, const char* rootdir, GError** erro
 {
     g_assert(def->regulatory_domain);
     g_autofree gchar* id_escaped = NULL;
-    g_autofree char* link = g_strjoin(NULL, rootdir ?: "", "/run/systemd/system/network.target.wants/netplan-regdom.service", NULL);
+    g_autofree char* link = g_strjoin(NULL, !!rootdir ? rootdir : "",
+                                      "/run/systemd/system/network.target.wants/netplan-regdom.service", NULL);
     g_autofree char* path = g_strjoin(NULL, "/run/systemd/system/netplan-regdom.service", NULL);
 
     GString* s = g_string_new("[Unit]\n");
@@ -1489,7 +1490,8 @@ _netplan_netdef_write_networkd(
     }
 
     if (def->type == NETPLAN_DEF_TYPE_WIFI || def->has_auth) {
-        g_autofree char* link = g_strjoin(NULL, rootdir ?: "", "/run/systemd/system/systemd-networkd.service.wants/netplan-wpa-", escaped_netdef_id, ".service", NULL);
+        g_autofree char* link = g_strjoin(NULL, !!rootdir ? rootdir : "",
+                                          "/run/systemd/system/systemd-networkd.service.wants/netplan-wpa-", escaped_netdef_id, ".service", NULL);
         g_autofree char* slink = g_strjoin(NULL, "/run/systemd/system/netplan-wpa-", escaped_netdef_id, ".service", NULL);
         if (def->type == NETPLAN_DEF_TYPE_WIFI && def->has_match) {
             g_set_error(error, NETPLAN_BACKEND_ERROR, NETPLAN_ERROR_UNSUPPORTED, "ERROR: %s: networkd backend does not support wifi with match:, only by interface name\n", def->id);