From 5a037827f61a2e78f3863bc5a08f1535882d7f6a Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 11 Oct 2013 05:20:24 +0200
Subject: [PATCH] bus: allow specifying NULL as type string when we want to
 construct messages with no payload

---
 src/libsystemd-bus/sd-bus.c | 45 ++++++++++++++++++++++---------------
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/src/libsystemd-bus/sd-bus.c b/src/libsystemd-bus/sd-bus.c
index 342af4d1d..542b5e8c4 100644
--- a/src/libsystemd-bus/sd-bus.c
+++ b/src/libsystemd-bus/sd-bus.c
@@ -3398,7 +3398,6 @@ int sd_bus_emit_signal(
                 const char *types, ...) {
 
         _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
-        va_list ap;
         int r;
 
         if (!bus)
@@ -3412,11 +3411,15 @@ int sd_bus_emit_signal(
         if (r < 0)
                 return r;
 
-        va_start(ap, types);
-        r = bus_message_append_ap(m, types, ap);
-        va_end(ap);
-        if (r < 0)
-                return r;
+        if (!isempty(types)) {
+                va_list ap;
+
+                va_start(ap, types);
+                r = bus_message_append_ap(m, types, ap);
+                va_end(ap);
+                if (r < 0)
+                        return r;
+        }
 
         return sd_bus_send(bus, m, NULL);
 }
@@ -3432,7 +3435,6 @@ int sd_bus_call_method(
                 const char *types, ...) {
 
         _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
-        va_list ap;
         int r;
 
         if (!bus)
@@ -3447,11 +3449,15 @@ int sd_bus_call_method(
         if (r < 0)
                 return r;
 
-        va_start(ap, types);
-        r = bus_message_append_ap(m, types, ap);
-        va_end(ap);
-        if (r < 0)
-                return r;
+        if (!isempty(types)) {
+                va_list ap;
+
+                va_start(ap, types);
+                r = bus_message_append_ap(m, types, ap);
+                va_end(ap);
+                if (r < 0)
+                        return r;
+        }
 
         return sd_bus_send_with_reply_and_block(bus, m, 0, error, reply);
 }
@@ -3462,7 +3468,6 @@ int sd_bus_reply_method_return(
                 const char *types, ...) {
 
         _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
-        va_list ap;
         int r;
 
         if (!bus)
@@ -3485,11 +3490,15 @@ int sd_bus_reply_method_return(
         if (r < 0)
                 return r;
 
-        va_start(ap, types);
-        r = bus_message_append_ap(m, types, ap);
-        va_end(ap);
-        if (r < 0)
-                return r;
+        if (!isempty(types)) {
+                va_list ap;
+
+                va_start(ap, types);
+                r = bus_message_append_ap(m, types, ap);
+                va_end(ap);
+                if (r < 0)
+                        return r;
+        }
 
         return sd_bus_send(bus, m, NULL);
 }
-- 
2.30.2