From d6f1b16baf8106d709e3fac585a12789dcb6bd29 Mon Sep 17 00:00:00 2001
From: Pavel Březina <pbrezina@redhat.com>
Date: Jun 27 2016 14:34:58 +0000
Subject: SBUS: Add string helper macros


Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>

---

diff --git a/src/providers/data_provider/dp_target_hostid.c b/src/providers/data_provider/dp_target_hostid.c
index a47601f..93f9fda 100644
--- a/src/providers/data_provider/dp_target_hostid.c
+++ b/src/providers/data_provider/dp_target_hostid.c
@@ -46,7 +46,7 @@ errno_t dp_host_handler(struct sbus_request *sbus_req,
     }
 
     data->name = name;
-    data->alias = alias[0] == '\0' ? NULL : alias;
+    data->alias = SBUS_SET_STRING(alias);
 
     key = talloc_asprintf(data, "%s:%s", name,
                           (data->alias == NULL ? "(null)" : data->alias));
diff --git a/src/providers/data_provider/dp_target_subdomains.c b/src/providers/data_provider/dp_target_subdomains.c
index 85e37f0..e29a9b9 100644
--- a/src/providers/data_provider/dp_target_subdomains.c
+++ b/src/providers/data_provider/dp_target_subdomains.c
@@ -40,7 +40,7 @@ errno_t dp_subdomains_handler(struct sbus_request *sbus_req,
     }
 
     data->domain_hint = domain_hint;
-    key = domain_hint[0] == '\0' ? "<ALL>" : domain_hint;
+    key = SBUS_IS_STRING_EMPTY(domain_hint) ? "<ALL>" : domain_hint;
 
     dp_req_with_reply(dp_cli, NULL, "Subdomains", key, sbus_req,
                       DPT_SUBDOMAINS, DPM_DOMAINS_HANDLER, 0, data,
diff --git a/src/sbus/sssd_dbus.h b/src/sbus/sssd_dbus.h
index 170b16b..fe1c4a7 100644
--- a/src/sbus/sssd_dbus.h
+++ b/src/sbus/sssd_dbus.h
@@ -61,6 +61,12 @@ struct sbus_request;
  */
 #define SBUS_SUBTREE_SUFFIX "/*"
 
+/**
+ * It is not possible to send NULL over D-Bus. We can only test if it
+ * is empty or not.
+ */
+#define SBUS_IS_STRING_EMPTY(str) ((str) == NULL || (str)[0] == '\0')
+#define SBUS_SET_STRING(str) (SBUS_IS_STRING_EMPTY(str) ? NULL : (str))
 
 
 typedef int (*sbus_msg_handler_fn)(struct sbus_request *dbus_req,