bus: also add error parameter to object find and enumerator callbacks

Just in order to bring things inline with the method and property
callbacks.

14 files changed, 138 insertions, 140 deletions

diff --git a/TODO b/TODO
index 6805fd6d1f..8acc879667 100644
--- a/TODO
+++ b/TODO
@@ -43,6 +43,8 @@ CGroup Rework Completion:
 
 Features:
 
+* bus: translate all EIO, EINVAL, .. errors into dbus error 1:1 and back.
+
 * add API to clone sd_bus_message objects
 
 * sd-bus: synthesized messages should get serial number (uint32_t) -1
diff --git a/src/core/dbus.c b/src/core/dbus.c
index 1cb4d0fa7d..d130e0974e 100644
--- a/src/core/dbus.c
+++ b/src/core/dbus.c
@@ -272,7 +272,7 @@ static int selinux_filter(sd_bus *bus, sd_bus_message *message, void *userdata,
         return 0;
 }
 
-static int bus_job_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata) {
+static int bus_job_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
         Manager *m = userdata;
         Job *j;
         int r;
@@ -291,7 +291,7 @@ static int bus_job_find(sd_bus *bus, const char *path, const char *interface, vo
         return 1;
 }
 
-static Unit *find_unit(Manager *m, sd_bus *bus, const char *path) {
+static int find_unit(Manager *m, sd_bus *bus, const char *path, Unit **unit, sd_bus_error *error) {
         Unit *u;
         int r;
 
@@ -305,25 +305,28 @@ static Unit *find_unit(Manager *m, sd_bus *bus, const char *path) {
 
                 message = sd_bus_get_current(bus);
                 if (!message)
-                        return NULL;
+                        return 0;
 
                 r = sd_bus_get_owner_pid(bus, sd_bus_message_get_sender(message), &pid);
                 if (r < 0)
-                        return NULL;
+                        return 0;
 
                 u = manager_get_unit_by_pid(m, pid);
         } else {
-                r = manager_load_unit_from_dbus_path(m, path, NULL, &u);
+                r = manager_load_unit_from_dbus_path(m, path, error, &u);
                 if (r < 0)
-                        return NULL;
+                        return 0;
         }
 
-        return u;
+        if (!u)
+                return 0;
+
+        *unit = u;
+        return 1;
 }
 
-static int bus_unit_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata) {
+static int bus_unit_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
         Manager *m = userdata;
-        Unit *u;
 
         assert(bus);
         assert(path);
@@ -331,17 +334,13 @@ static int bus_unit_find(sd_bus *bus, const char *path, const char *interface, v
         assert(found);
         assert(m);
 
-        u = find_unit(m, bus, path);
-        if (!u)
-                return 0;
-
-        *found = u;
-        return 1;
+        return find_unit(m, bus, path, (Unit**) found, error);
 }
 
-static int bus_unit_interface_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata) {
+static int bus_unit_interface_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
         Manager *m = userdata;
         Unit *u;
+        int r;
 
         assert(bus);
         assert(path);
@@ -349,9 +348,9 @@ static int bus_unit_interface_find(sd_bus *bus, const char *path, const char *in
         assert(found);
         assert(m);
 
-        u = find_unit(m, bus, path);
-        if (!u)
-                return 0;
+        r = find_unit(m, bus, path, &u, error);
+        if (r <= 0)
+                return r;
 
         if (!streq_ptr(interface, UNIT_VTABLE(u)->bus_interface))
                 return 0;
@@ -360,9 +359,10 @@ static int bus_unit_interface_find(sd_bus *bus, const char *path, const char *in
         return 1;
 }
 
-static int bus_unit_cgroup_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata) {
+static int bus_unit_cgroup_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
         Manager *m = userdata;
         Unit *u;
+        int r;
 
         assert(bus);
         assert(path);
@@ -370,9 +370,9 @@ static int bus_unit_cgroup_find(sd_bus *bus, const char *path, const char *inter
         assert(found);
         assert(m);
 
-        u = find_unit(m, bus, path);
-        if (!u)
-                return 0;
+        r = find_unit(m, bus, path, &u, error);
+        if (r <= 0)
+                return r;
 
         if (!streq_ptr(interface, UNIT_VTABLE(u)->bus_interface))
                 return 0;
@@ -384,10 +384,11 @@ static int bus_unit_cgroup_find(sd_bus *bus, const char *path, const char *inter
         return 1;
 }
 
-static int bus_cgroup_context_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata) {
+static int bus_cgroup_context_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
         Manager *m = userdata;
         CGroupContext *c;
         Unit *u;
+        int r;
 
         assert(bus);
         assert(path);
@@ -395,9 +396,9 @@ static int bus_cgroup_context_find(sd_bus *bus, const char *path, const char *in
         assert(found);
         assert(m);
 
-        u = find_unit(m, bus, path);
-        if (!u)
-                return 0;
+        r = find_unit(m, bus, path, &u, error);
+        if (r <= 0)
+                return r;
 
         if (!streq_ptr(interface, UNIT_VTABLE(u)->bus_interface))
                 return 0;
@@ -410,10 +411,11 @@ static int bus_cgroup_context_find(sd_bus *bus, const char *path, const char *in
         return 1;
 }
 
-static int bus_exec_context_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata) {
+static int bus_exec_context_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
         Manager *m = userdata;
         ExecContext *c;
         Unit *u;
+        int r;
 
         assert(bus);
         assert(path);
@@ -421,9 +423,9 @@ static int bus_exec_context_find(sd_bus *bus, const char *path, const char *inte
         assert(found);
         assert(m);
 
-        u = find_unit(m, bus, path);
-        if (!u)
-                return 0;
+        r = find_unit(m, bus, path, &u, error);
+        if (r <= 0)
+                return r;
 
         if (!streq_ptr(interface, UNIT_VTABLE(u)->bus_interface))
                 return 0;
@@ -436,10 +438,11 @@ static int bus_exec_context_find(sd_bus *bus, const char *path, const char *inte
         return 1;
 }
 
-static int bus_kill_context_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata) {
+static int bus_kill_context_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
         Manager *m = userdata;
         KillContext *c;
         Unit *u;
+        int r;
 
         assert(bus);
         assert(path);
@@ -447,9 +450,9 @@ static int bus_kill_context_find(sd_bus *bus, const char *path, const char *inte
         assert(found);
         assert(m);
 
-        u = find_unit(m, bus, path);
-        if (!u)
-                return 0;
+        r = find_unit(m, bus, path, &u, error);
+        if (r <= 0)
+                return r;
 
         if (!streq_ptr(interface, UNIT_VTABLE(u)->bus_interface))
                 return 0;
@@ -462,7 +465,7 @@ static int bus_kill_context_find(sd_bus *bus, const char *path, const char *inte
         return 1;
 }
 
-static int bus_job_enumerate(sd_bus *bus, const char *path, char ***nodes, void *userdata) {
+static int bus_job_enumerate(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error) {
         _cleanup_free_ char **l = NULL;
         Manager *m = userdata;
         unsigned k = 0;
@@ -489,7 +492,7 @@ static int bus_job_enumerate(sd_bus *bus, const char *path, char ***nodes, void
         return k;
 }
 
-static int bus_unit_enumerate(sd_bus *bus, const char *path, char ***nodes, void *userdata) {
+static int bus_unit_enumerate(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error) {
         _cleanup_free_ char **l = NULL;
         Manager *m = userdata;
         unsigned k = 0;
diff --git a/src/libsystemd-bus/bus-objects.c b/src/libsystemd-bus/bus-objects.c
index 06be5ed7d8..7c8a774e73 100644
--- a/src/libsystemd-bus/bus-objects.c
+++ b/src/libsystemd-bus/bus-objects.c
@@ -33,7 +33,8 @@ static int node_vtable_get_userdata(
                 sd_bus *bus,
                 const char *path,
                 struct node_vtable *c,
-                void **userdata) {
+                void **userdata,
+                sd_bus_error *error) {
 
         void *u;
         int r;
@@ -44,8 +45,12 @@ static int node_vtable_get_userdata(
 
         u = c->userdata;
         if (c->find) {
-                r = c->find(bus, path, c->interface, &u, u);
-                if (r <= 0)
+                r = c->find(bus, path, c->interface, u, &u, error);
+                if (r < 0)
+                        return r;
+                if (sd_bus_error_is_set(error))
+                        return sd_bus_error_get_errno(error);
+                if (r == 0)
                         return r;
         }
 
@@ -65,7 +70,8 @@ static int vtable_property_get_userdata(
                 sd_bus *bus,
                 const char *path,
                 struct vtable_member *p,
-                void **userdata) {
+                void **userdata,
+                sd_bus_error *error) {
 
         void *u;
         int r;
@@ -75,7 +81,7 @@ static int vtable_property_get_userdata(
         assert(p);
         assert(userdata);
 
-        r = node_vtable_get_userdata(bus, path, p->parent, &u);
+        r = node_vtable_get_userdata(bus, path, p->parent, &u, error);
         if (r <= 0)
                 return r;
         if (bus->nodes_modified)
@@ -89,7 +95,8 @@ static int add_enumerated_to_set(
                 sd_bus *bus,
                 const char *prefix,
                 struct node_enumerator *first,
-                Set *s) {
+                Set *s,
+                sd_bus_error *error) {
 
         struct node_enumerator *c;
         int r;
@@ -104,9 +111,11 @@ static int add_enumerated_to_set(
                 if (bus->nodes_modified)
                         return 0;
 
-                r = c->callback(bus, prefix, &children, c->userdata);
+                r = c->callback(bus, prefix, c->userdata, &children, error);
                 if (r < 0)
                         return r;
+                if (sd_bus_error_is_set(error))
+                        return sd_bus_error_get_errno(error);
 
                 STRV_FOREACH(k, children) {
                         if (r < 0) {
@@ -140,7 +149,8 @@ static int add_subtree_to_set(
                 sd_bus *bus,
                 const char *prefix,
                 struct node *n,
-                Set *s) {
+                Set *s,
+                sd_bus_error *error) {
 
         struct node *i;
         int r;
@@ -150,7 +160,7 @@ static int add_subtree_to_set(
         assert(n);
         assert(s);
 
-        r = add_enumerated_to_set(bus, prefix, n->enumerators, s);
+        r = add_enumerated_to_set(bus, prefix, n->enumerators, s, error);
         if (r < 0)
                 return r;
         if (bus->nodes_modified)
@@ -170,7 +180,7 @@ static int add_subtree_to_set(
                 if (r < 0 && r != -EEXIST)
                         return r;
 
-                r = add_subtree_to_set(bus, prefix, i, s);
+                r = add_subtree_to_set(bus, prefix, i, s, error);
                 if (r < 0)
                         return r;
                 if (bus->nodes_modified)
@@ -184,7 +194,8 @@ static int get_child_nodes(
                 sd_bus *bus,
                 const char *prefix,
                 struct node *n,
-                Set **_s) {
+                Set **_s,
+                sd_bus_error *error) {
 
         Set *s = NULL;
         int r;
@@ -198,7 +209,7 @@ static int get_child_nodes(
         if (!s)
                 return -ENOMEM;
 
-        r = add_subtree_to_set(bus, prefix, n, s);
+        r = add_subtree_to_set(bus, prefix, n, s, error);
         if (r < 0) {
                 set_free_free(s);
                 return r;
@@ -258,6 +269,7 @@ static int method_callbacks_run(
                 bool require_fallback,
                 bool *found_object) {
 
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         const char *signature;
         void *u;
         int r;
@@ -270,9 +282,9 @@ static int method_callbacks_run(
         if (require_fallback && !c->parent->is_fallback)
                 return 0;
 
-        r = node_vtable_get_userdata(bus, m->path, c->parent, &u);
+        r = node_vtable_get_userdata(bus, m->path, c->parent, &u, &error);
         if (r <= 0)
-                return r;
+                return bus_maybe_reply_error(m, r, &error);
         if (bus->nodes_modified)
                 return 0;
 
@@ -291,20 +303,16 @@ static int method_callbacks_run(
         if (!signature)
                 return -EINVAL;
 
-        if (!streq(strempty(c->vtable->x.method.signature), signature)) {
+        if (!streq(strempty(c->vtable->x.method.signature), signature))
                 return sd_bus_reply_method_errorf(
                                 m,
                                 SD_BUS_ERROR_INVALID_ARGS,
                                 "Invalid arguments '%s' to call %s.%s(), expecting '%s'.",
                                 signature, c->interface, c->member, strempty(c->vtable->x.method.signature));
-        }
 
         if (c->vtable->x.method.handler) {
-                _cleanup_bus_error_free_ sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
-
-                r = c->vtable->x.method.handler(bus, m, u, &error_buffer);
-
-                return bus_maybe_reply_error(m, r, &error_buffer);
+                r = c->vtable->x.method.handler(bus, m, u, &error);
+                return bus_maybe_reply_error(m, r, &error);
         }
 
         /* If the method callback is NULL, make this a successful NOP */
@@ -326,6 +334,7 @@ static int invoke_property_get(
                 sd_bus_error *error) {
 
         const void *p;
+        int r;
 
         assert(bus);
         assert(v);
@@ -334,8 +343,14 @@ static int invoke_property_get(
         assert(property);
         assert(reply);
 
-        if (v->x.property.get)
-                return v->x.property.get(bus, path, interface, property, reply, userdata, error);
+        if (v->x.property.get) {
+                r = v->x.property.get(bus, path, interface, property, reply, userdata, error);
+                if (r < 0)
+                        return r;
+                if (sd_bus_error_is_set(error))
+                        return sd_bus_error_get_errno(error);
+                return r;
+        }
 
         /* Automatic handling if no callback is defined. */
 
@@ -384,8 +399,14 @@ static int invoke_property_set(
         assert(property);
         assert(value);
 
-        if (v->x.property.set)
-                return v->x.property.set(bus, path, interface, property, value, userdata, error);
+        if (v->x.property.set) {
+                r = v->x.property.set(bus, path, interface, property, value, userdata, error);
+                if (r < 0)
+                        return r;
+                if (sd_bus_error_is_set(error))
+                        return sd_bus_error_get_errno(error);
+                return r;
+        }
 
         /*  Automatic handling if no callback is defined. */
 
@@ -446,9 +467,9 @@ static int property_get_set_callbacks_run(
         if (require_fallback && !c->parent->is_fallback)
                 return 0;
 
-        r = vtable_property_get_userdata(bus, m->path, c, &u);
+        r = vtable_property_get_userdata(bus, m->path, c, &u, &error);
         if (r <= 0)
-                return r;
+                return bus_maybe_reply_error(m, r, &error);
         if (bus->nodes_modified)
                 return 0;
 
@@ -472,9 +493,7 @@ static int property_get_set_callbacks_run(
 
                 r = invoke_property_get(bus, c->vtable, m->path, c->interface, c->member, reply, u, &error);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(m, r, &error);
-                if (sd_bus_error_is_set(&error))
-                        return sd_bus_reply_method_error(m, &error);
+                        return bus_maybe_reply_error(m, r, &error);
 
                 if (bus->nodes_modified)
                         return 0;
@@ -501,9 +520,7 @@ static int property_get_set_callbacks_run(
 
                 r = invoke_property_set(bus, c->vtable, m->path, c->interface, c->member, m, u, &error);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(m, r, &error);
-                if (sd_bus_error_is_set(&error))
-                        return sd_bus_reply_method_error(m, &error);
+                        return bus_maybe_reply_error(m, r, &error);
 
                 if (bus->nodes_modified)
                         return 0;
@@ -553,12 +570,8 @@ static int vtable_append_all_properties(
                         return r;
 
                 r = invoke_property_get(bus, v, path, c->interface, v->x.property.member, reply, vtable_property_convert_userdata(v, userdata), error);
-                if (sd_bus_error_is_set(error))
-                        return 0;
-                if (r < 0) {
-                        sd_bus_error_set_errno(error, r);
-                        return 0;
-                }
+                if (r < 0)
+                        return r;
                 if (bus->nodes_modified)
                         return 0;
 
@@ -611,9 +624,9 @@ static int property_get_all_callbacks_run(
                 if (require_fallback && !c->is_fallback)
                         continue;
 
-                r = node_vtable_get_userdata(bus, m->path, c, &u);
+                r = node_vtable_get_userdata(bus, m->path, c, &u, &error);
                 if (r < 0)
-                        return r;
+                        return bus_maybe_reply_error(m, r, &error);
                 if (bus->nodes_modified)
                         return 0;
                 if (r == 0)
@@ -627,15 +640,7 @@ static int property_get_all_callbacks_run(
 
                 r = vtable_append_all_properties(bus, reply, m->path, c, u, &error);
                 if (r < 0)
-                        return r;
-
-                if (sd_bus_error_is_set(&error)) {
-                        r = sd_bus_reply_method_error(m, &error);
-                        if (r < 0)
-                                return r;
-
-                        return 1;
-                }
+                        return bus_maybe_reply_error(m, r, &error);
                 if (bus->nodes_modified)
                         return 0;
         }
@@ -699,11 +704,12 @@ static bool bus_node_exists(
         }
 
         LIST_FOREACH(vtables, c, n->vtables) {
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 
                 if (require_fallback && !c->is_fallback)
                         continue;
 
-                if (node_vtable_get_userdata(bus, path, c, NULL) > 0)
+                if (node_vtable_get_userdata(bus, path, c, NULL, &error) > 0)
                         return true;
                 if (bus->nodes_modified)
                         return false;
@@ -719,6 +725,7 @@ static int process_introspect(
                 bool require_fallback,
                 bool *found_object) {
 
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
         _cleanup_set_free_free_ Set *s = NULL;
         const char *previous_interface = NULL;
@@ -732,9 +739,9 @@ static int process_introspect(
         assert(n);
         assert(found_object);
 
-        r = get_child_nodes(bus, m->path, n, &s);
+        r = get_child_nodes(bus, m->path, n, &s, &error);
         if (r < 0)
-                return r;
+                return bus_maybe_reply_error(m, r, &error);
         if (bus->nodes_modified)
                 return 0;
 
@@ -752,11 +759,15 @@ static int process_introspect(
                 if (require_fallback && !c->is_fallback)
                         continue;
 
-                r = node_vtable_get_userdata(bus, m->path, c, NULL);
-                if (r < 0)
-                        return r;
-                if (bus->nodes_modified)
-                        return 0;
+                r = node_vtable_get_userdata(bus, m->path, c, NULL, &error);
+                if (r < 0) {
+                        r = bus_maybe_reply_error(m, r, &error);
+                        goto finish;
+                }
+                if (bus->nodes_modified) {
+                        r = 0;
+                        goto finish;
+                }
                 if (r == 0)
                         continue;
 
@@ -843,7 +854,7 @@ static int object_manager_serialize_path(
                 if (require_fallback && !i->is_fallback)
                         continue;
 
-                r = node_vtable_get_userdata(bus, path, i, &u);
+                r = node_vtable_get_userdata(bus, path, i, &u, error);
                 if (r < 0)
                         return r;
                 if (bus->nodes_modified)
@@ -902,8 +913,6 @@ static int object_manager_serialize_path(
                 r = vtable_append_all_properties(bus, reply, path, i, u, error);
                 if (r < 0)
                         return r;
-                if (sd_bus_error_is_set(error))
-                        return 0;
                 if (bus->nodes_modified)
                         return 0;
 
@@ -951,8 +960,6 @@ static int object_manager_serialize_path_and_fallbacks(
         r = object_manager_serialize_path(bus, reply, path, path, false, error);
         if (r < 0)
                 return r;
-        if (sd_bus_error_is_set(error))
-                return 0;
         if (bus->nodes_modified)
                 return 0;
 
@@ -962,8 +969,6 @@ static int object_manager_serialize_path_and_fallbacks(
                 r = object_manager_serialize_path(bus, reply, prefix, path, true, error);
                 if (r < 0)
                         return r;
-                if (sd_bus_error_is_set(error))
-                        return 0;
                 if (bus->nodes_modified)
                         return 0;
         }
@@ -978,6 +983,7 @@ static int process_get_managed_objects(
                 bool require_fallback,
                 bool *found_object) {
 
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
         _cleanup_set_free_free_ Set *s = NULL;
         bool empty;
@@ -991,7 +997,7 @@ static int process_get_managed_objects(
         if (!bus_node_with_object_manager(bus, n))
                 return 0;
 
-        r = get_child_nodes(bus, m->path, n, &s);
+        r = get_child_nodes(bus, m->path, n, &s, &error);
         if (r < 0)
                 return r;
         if (bus->nodes_modified)
@@ -1034,19 +1040,9 @@ static int process_get_managed_objects(
                 char *path;
 
                 SET_FOREACH(path, s, i) {
-                        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
-
                         r = object_manager_serialize_path_and_fallbacks(bus, reply, path, &error);
                         if (r < 0)
-                                return -ENOMEM;
-
-                        if (sd_bus_error_is_set(&error)) {
-                                r = sd_bus_reply_method_error(m, &error);
-                                if (r < 0)
-                                        return r;
-
-                                return 1;
-                        }
+                                return r;
 
                         if (bus->nodes_modified)
                                 return 0;
@@ -1851,6 +1847,7 @@ static int emit_properties_changed_on_interface(
                 bool require_fallback,
                 char **names) {
 
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
         bool has_invalidating = false, has_changing = false;
         struct vtable_member key = {};
@@ -1891,7 +1888,7 @@ static int emit_properties_changed_on_interface(
                 if (!streq(c->interface, interface))
                         continue;
 
-                r = node_vtable_get_userdata(bus, path, c, &u);
+                r = node_vtable_get_userdata(bus, path, c, &u, &error);
                 if (r < 0)
                         return r;
                 if (bus->nodes_modified)
@@ -1900,7 +1897,6 @@ static int emit_properties_changed_on_interface(
                         continue;
 
                 STRV_FOREACH(property, names) {
-                        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
                         struct vtable_member *v;
 
                         assert_return(member_name_is_valid(*property), -EINVAL);
@@ -1940,8 +1936,6 @@ static int emit_properties_changed_on_interface(
                         r = invoke_property_get(bus, v->vtable, m->path, interface, *property, m, vtable_property_convert_userdata(v->vtable, u), &error);
                         if (r < 0)
                                 return r;
-                        if (sd_bus_error_is_set(&error))
-                                return sd_bus_error_get_errno(&error);
                         if (bus->nodes_modified)
                                 return 0;
 
@@ -1974,7 +1968,7 @@ static int emit_properties_changed_on_interface(
                         if (!streq(c->interface, interface))
                                 continue;
 
-                        r = node_vtable_get_userdata(bus, path, c, &u);
+                        r = node_vtable_get_userdata(bus, path, c, &u, &error);
                         if (r < 0)
                                 return r;
                         if (bus->nodes_modified)
@@ -2106,7 +2100,7 @@ static int interfaces_added_append_one_prefix(
                 if (!streq(c->interface, interface))
                         continue;
 
-                r = node_vtable_get_userdata(bus, path, c, &u);
+                r = node_vtable_get_userdata(bus, path, c, &u, &error);
                 if (r < 0)
                         return r;
                 if (bus->nodes_modified)
diff --git a/src/libsystemd-bus/test-bus-objects.c b/src/libsystemd-bus/test-bus-objects.c
index 043aa90b3c..95278e36e3 100644
--- a/src/libsystemd-bus/test-bus-objects.c
+++ b/src/libsystemd-bus/test-bus-objects.c
@@ -182,7 +182,7 @@ static const sd_bus_vtable vtable2[] = {
         SD_BUS_VTABLE_END
 };
 
-static int enumerator_callback(sd_bus *b, const char *path, char ***nodes, void *userdata) {
+static int enumerator_callback(sd_bus *b, const char *path, void *userdata, char ***nodes, sd_bus_error *error) {
 
         if (object_path_startswith("/value", path))
                 assert_se(*nodes = strv_new("/value/a", "/value/b", "/value/c", NULL));
diff --git a/src/login/logind-seat-dbus.c b/src/login/logind-seat-dbus.c
index 488d007c7e..f274c0d639 100644
--- a/src/login/logind-seat-dbus.c
+++ b/src/login/logind-seat-dbus.c
@@ -254,7 +254,7 @@ const sd_bus_vtable seat_vtable[] = {
         SD_BUS_VTABLE_END
 };
 
-int seat_object_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata) {
+int seat_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
         Manager *m = userdata;
         Seat *seat;
         int r;
@@ -319,7 +319,7 @@ char *seat_bus_path(Seat *s) {
         return strappend("/org/freedesktop/login1/seat/", t);
 }
 
-int seat_node_enumerator(sd_bus *bus, const char *path, char ***nodes, void *userdata) {
+int seat_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error) {
         _cleanup_strv_free_ char **l = NULL;
         Manager *m = userdata;
         Seat *seat;
diff --git a/src/login/logind-seat.h b/src/login/logind-seat.h
index 0547dec072..80c6b8bd92 100644
--- a/src/login/logind-seat.h
+++ b/src/login/logind-seat.h
@@ -82,8 +82,8 @@ bool seat_name_is_valid(const char *name);
 
 extern const sd_bus_vtable seat_vtable[];
 
-int seat_node_enumerator(sd_bus *bus, const char *path, char ***nodes, void *userdata);
-int seat_object_find(sd_bus *bus, const char *path, const char *interface, void **found, void *seatdata);
+int seat_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error);
+int seat_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error);
 char *seat_bus_path(Seat *s);
 
 int seat_send_signal(Seat *s, bool new_seat);
diff --git a/src/login/logind-session-dbus.c b/src/login/logind-session-dbus.c
index d2e2364fc2..9f3217baf5 100644
--- a/src/login/logind-session-dbus.c
+++ b/src/login/logind-session-dbus.c
@@ -465,7 +465,7 @@ const sd_bus_vtable session_vtable[] = {
         SD_BUS_VTABLE_END
 };
 
-int session_object_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata) {
+int session_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
         Manager *m = userdata;
         Session *session;
         int r;
@@ -524,7 +524,7 @@ char *session_bus_path(Session *s) {
         return strappend("/org/freedesktop/login1/session/", t);
 }
 
-int session_node_enumerator(sd_bus *bus, const char *path, char ***nodes, void *userdata) {
+int session_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error) {
         _cleanup_strv_free_ char **l = NULL;
         Manager *m = userdata;
         Session *session;
diff --git a/src/login/logind-session.h b/src/login/logind-session.h
index bcbd4e5625..f7a9dbc249 100644
--- a/src/login/logind-session.h
+++ b/src/login/logind-session.h
@@ -139,8 +139,8 @@ int session_kill(Session *s, KillWho who, int signo);
 SessionState session_get_state(Session *u);
 
 extern const sd_bus_vtable session_vtable[];
-int session_node_enumerator(sd_bus *bus, const char *path, char ***nodes, void *userdata);
-int session_object_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata);
+int session_node_enumerator(sd_bus *bus, const char *path,void *userdata, char ***nodes, sd_bus_error *error);
+int session_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error);
 char *session_bus_path(Session *s);
 
 int session_send_signal(Session *s, bool new_session);
diff --git a/src/login/logind-user-dbus.c b/src/login/logind-user-dbus.c
index 3942fa9bec..6a77e33eea 100644
--- a/src/login/logind-user-dbus.c
+++ b/src/login/logind-user-dbus.c
@@ -235,7 +235,7 @@ const sd_bus_vtable user_vtable[] = {
         SD_BUS_VTABLE_END
 };
 
-int user_object_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata) {
+int user_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
         Manager *m = userdata;
         User *user;
         int r;
@@ -293,7 +293,7 @@ char *user_bus_path(User *u) {
         return s;
 }
 
-int user_node_enumerator(sd_bus *bus, const char *path, char ***nodes, void *userdata) {
+int user_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error) {
         _cleanup_strv_free_ char **l = NULL;
         Manager *m = userdata;
         User *user;
diff --git a/src/login/logind-user.h b/src/login/logind-user.h
index 8d396c681d..8d5f119e66 100644
--- a/src/login/logind-user.h
+++ b/src/login/logind-user.h
@@ -82,8 +82,8 @@ int user_kill(User *u, int signo);
 int user_check_linger_file(User *u);
 
 extern const sd_bus_vtable user_vtable[];
-int user_node_enumerator(sd_bus *bus, const char *path, char ***nodes, void *userdata);
-int user_object_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata);
+int user_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error);
+int user_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error);
 char *user_bus_path(User *s);
 
 int user_send_signal(User *u, bool new_user);
diff --git a/src/machine/machine-dbus.c b/src/machine/machine-dbus.c
index 2c7f3a798e..c6a794b5e8 100644
--- a/src/machine/machine-dbus.c
+++ b/src/machine/machine-dbus.c
@@ -142,7 +142,7 @@ const sd_bus_vtable machine_vtable[] = {
         SD_BUS_VTABLE_END
 };
 
-int machine_object_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata) {
+int machine_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
         Manager *m = userdata;
         Machine *machine;
         int r;
@@ -201,7 +201,7 @@ char *machine_bus_path(Machine *m) {
         return strappend("/org/freedesktop/machine1/machine/", e);
 }
 
-int machine_node_enumerator(sd_bus *bus, const char *path, char ***nodes, void *userdata) {
+int machine_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error) {
         _cleanup_strv_free_ char **l = NULL;
         Machine *machine = NULL;
         Manager *m = userdata;
diff --git a/src/machine/machine.h b/src/machine/machine.h
index 99ee25888e..62e4b2b340 100644
--- a/src/machine/machine.h
+++ b/src/machine/machine.h
@@ -93,7 +93,8 @@ MachineState machine_get_state(Machine *u);
 extern const sd_bus_vtable machine_vtable[];
 
 char *machine_bus_path(Machine *s);
-int machine_object_find(sd_bus *bus, const char *path, const char *interface, void **found, void *userdata);
+int machine_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error);
+int machine_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error);
 
 int machine_send_signal(Machine *m, bool new_machine);
 int machine_send_create_reply(Machine *m, sd_bus_error *error);
diff --git a/src/machine/machined.h b/src/machine/machined.h
index 0b074c4e8a..d4b581be7a 100644
--- a/src/machine/machined.h
+++ b/src/machine/machined.h
@@ -60,8 +60,6 @@ int manager_get_machine_by_pid(Manager *m, pid_t pid, Machine **machine);
 
 extern const sd_bus_vtable manager_vtable[];
 
-int machine_node_enumerator(sd_bus *bus, const char *path, char ***nodes, void *userdata);
-
 int match_reloading(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error);
 int match_unit_removed(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error);
 int match_properties_changed(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error);
diff --git a/src/systemd/sd-bus.h b/src/systemd/sd-bus.h
index 582720815a..8954e38791 100644
--- a/src/systemd/sd-bus.h
+++ b/src/systemd/sd-bus.h
@@ -49,8 +49,8 @@ typedef struct {
 typedef int (*sd_bus_message_handler_t)(sd_bus *bus, sd_bus_message *m, void *userdata, sd_bus_error *ret_error);
 typedef int (*sd_bus_property_get_t) (sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, void *userdata, sd_bus_error *ret_error);
 typedef int (*sd_bus_property_set_t) (sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *value, void *userdata, sd_bus_error *ret_error);
-typedef int (*sd_bus_object_find_t) (sd_bus *bus, const char *path, const char *interface, void **found, void *userdata);
-typedef int (*sd_bus_node_enumerator_t) (sd_bus *bus, const char *path, char ***nodes, void *userdata);
+typedef int (*sd_bus_object_find_t) (sd_bus *bus, const char *path, const char *interface, void *userdata, void **ret_found, sd_bus_error *ret_error);
+typedef int (*sd_bus_node_enumerator_t) (sd_bus *bus, const char *path, void *userdata, char ***ret_nodes, sd_bus_error *ret_error);
 
 #include "sd-bus-protocol.h"
 #include "sd-bus-vtable.h"