From a6aa89122d2fa5e811a72200773068c13bfffea2 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 3 Dec 2013 19:55:51 +0100
Subject: [PATCH] bus: don't make use of the private bus socket if kdbus is
 available

---
 src/core/dbus.c               |  4 +++
 src/core/manager.c            |  2 +-
 src/libsystemd-bus/bus-util.c | 67 ++++++++++++++++++++++++++++-------
 3 files changed, 59 insertions(+), 14 deletions(-)

diff --git a/src/core/dbus.c b/src/core/dbus.c
index cab7628ad..25d83a694 100644
--- a/src/core/dbus.c
+++ b/src/core/dbus.c
@@ -938,6 +938,10 @@ static int bus_init_private(Manager *m) {
         if (m->private_listen_fd >= 0)
                 return 0;
 
+        /* We don't need the private socket if we have kdbus */
+        if (m->kdbus_fd >= 0)
+                return 0;
+
         if (m->running_as == SYSTEMD_SYSTEM) {
 
                 /* We want the private bus only when running as init */
diff --git a/src/core/manager.c b/src/core/manager.c
index 19493861e..0a3e840de 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -428,7 +428,7 @@ static int manager_setup_kdbus(Manager *m) {
                 return m->kdbus_fd;
         }
 
-        log_info("Successfully set up kdbus on %s", p);
+        log_debug("Successfully set up kdbus on %s", p);
 #endif
 
         return 0;
diff --git a/src/libsystemd-bus/bus-util.c b/src/libsystemd-bus/bus-util.c
index 1945f4799..0a3f6b85f 100644
--- a/src/libsystemd-bus/bus-util.c
+++ b/src/libsystemd-bus/bus-util.c
@@ -439,21 +439,43 @@ int bus_open_system_systemd(sd_bus **_bus) {
         if (geteuid() != 0)
                 return sd_bus_open_system(_bus);
 
-        /* If we are root, then let's talk directly to the system
-         * instance, instead of going via the bus */
+        /* If we are root and kdbus is not available, then let's talk
+         * directly to the system instance, instead of going via the
+         * bus */
 
+#ifdef ENABLE_KDBUS
         r = sd_bus_new(&bus);
         if (r < 0)
                 return r;
 
-        r = sd_bus_set_address(bus, "unix:path=/run/systemd/private");
+        r = sd_bus_set_address(bus, "kernel:path=/dev/kdbus/0-system/bus");
         if (r < 0)
                 return r;
 
+        bus->bus_client = true;
+
         r = sd_bus_start(bus);
+        if (r >= 0) {
+                *_bus = bus;
+                bus = NULL;
+                return 0;
+        }
+
+        bus = sd_bus_unref(bus);
+#endif
+
+        r = sd_bus_new(&bus);
         if (r < 0)
                 return r;
 
+        r = sd_bus_set_address(bus, "unix:path=/run/systemd/private");
+        if (r < 0)
+                return r;
+
+        r = sd_bus_start(bus);
+        if (r < 0)
+                return sd_bus_open_system(_bus);
+
         r = bus_check_peercred(bus);
         if (r < 0)
                 return r;
@@ -466,34 +488,53 @@ int bus_open_system_systemd(sd_bus **_bus) {
 
 int bus_open_user_systemd(sd_bus **_bus) {
         _cleanup_bus_unref_ sd_bus *bus = NULL;
-        _cleanup_free_ char *p = NULL;
+        _cleanup_free_ char *ee = NULL;
         const char *e;
         int r;
 
-        /* If we are supposed to talk to the instance, try via
-         * XDG_RUNTIME_DIR first, then fallback to normal bus
-         * access */
+        /* Try via kdbus first, and then directly */
 
         assert(_bus);
 
+#ifdef ENABLE_KDBUS
+        r = sd_bus_new(&bus);
+        if (r < 0)
+                return r;
+
+        if (asprintf(&bus->address, "kernel:path=/dev/kdbus/%lu-user/bus", (unsigned long) getuid()) < 0)
+                return -ENOMEM;
+
+        bus->bus_client = true;
+
+        r = sd_bus_start(bus);
+        if (r >= 0) {
+                *_bus = bus;
+                bus = NULL;
+                return 0;
+        }
+
+        bus = sd_bus_unref(bus);
+#endif
+
         e = secure_getenv("XDG_RUNTIME_DIR");
         if (!e)
-                return sd_bus_open_user(_bus);
+                return sd_bus_open_system(_bus);
 
-        if (asprintf(&p, "unix:path=%s/systemd/private", e) < 0)
+        ee = bus_address_escape(e);
+        if (!ee)
                 return -ENOMEM;
 
         r = sd_bus_new(&bus);
         if (r < 0)
                 return r;
 
-        r = sd_bus_set_address(bus, p);
-        if (r < 0)
-                return r;
+        bus->address = strjoin("unix:path=", ee, "/systemd/private", NULL);
+        if (!bus->address)
+                return -ENOMEM;
 
         r = sd_bus_start(bus);
         if (r < 0)
-                return r;
+                return sd_bus_open_system(_bus);
 
         r = bus_check_peercred(bus);
         if (r < 0)
-- 
2.30.2