libsystemd-bus: add lightweight object vtable implementation for exposing objects on the bus

This adds a lightweight scheme how to define interfaces in static fixed
arrays which then can be easily registered on a bus connection. This
makes it much easier to write bus services.

This automatically handles implementation of the Properties,
ObjectManager, and Introspection bus interfaces.

1 files changed, 1815 insertions, 158 deletions

diff --git a/src/libsystemd-bus/sd-bus.c b/src/libsystemd-bus/sd-bus.c
index db0880f21c..b1dcd8dc62 100644
--- a/src/libsystemd-bus/sd-bus.c
+++ b/src/libsystemd-bus/sd-bus.c
@@ -42,6 +42,8 @@
 #include "bus-socket.h"
 #include "bus-kernel.h"
 #include "bus-control.h"
+#include "bus-introspect.h"
+#include "bus-signature.h"
 
 static int bus_poll(sd_bus *bus, bool need_more, uint64_t timeout_usec);
 
@@ -57,9 +59,46 @@ static void bus_close_fds(sd_bus *b) {
         b->input_fd = b->output_fd = -1;
 }
 
+static void bus_node_destroy(sd_bus *b, struct node *n) {
+        struct node_callback *c;
+        struct node_vtable *v;
+        struct node_enumerator *e;
+
+        assert(b);
+
+        if (!n)
+                return;
+
+        while (n->child)
+                bus_node_destroy(b, n->child);
+
+        while ((c = n->callbacks)) {
+                LIST_REMOVE(struct node_callback, callbacks, n->callbacks, c);
+                free(c);
+        }
+
+        while ((v = n->vtables)) {
+                LIST_REMOVE(struct node_vtable, vtables, n->vtables, v);
+                free(v->interface);
+                free(v);
+        }
+
+        while ((e = n->enumerators)) {
+                LIST_REMOVE(struct node_enumerator, enumerators, n->enumerators, e);
+                free(e);
+        }
+
+        if (n->parent)
+                LIST_REMOVE(struct node, siblings, n->parent->child, n);
+
+        assert_se(hashmap_remove(b->nodes, n->path) == n);
+        free(n->path);
+        free(n);
+}
+
 static void bus_free(sd_bus *b) {
         struct filter_callback *f;
-        struct object_callback *c;
+        struct node *n;
         unsigned i;
 
         assert(b);
@@ -97,14 +136,16 @@ static void bus_free(sd_bus *b) {
                 free(f);
         }
 
-        while ((c = hashmap_steal_first(b->object_callbacks))) {
-                free(c->path);
-                free(c);
-        }
-
-        hashmap_free(b->object_callbacks);
         bus_match_free(&b->match_callbacks);
 
+        hashmap_free_free(b->vtable_methods);
+        hashmap_free_free(b->vtable_properties);
+
+        while ((n = hashmap_first(b->nodes)))
+                bus_node_destroy(b, n);
+
+        hashmap_free(b->nodes);
+
         bus_kernel_flush_memfd(b);
 
         assert_se(pthread_mutex_destroy(&b->memfd_cache_mutex) == 0);
@@ -1818,13 +1859,10 @@ static int process_builtin(sd_bus *bus, sd_bus_message *m) {
 
                 r = sd_bus_message_append(reply, "s", sd_id128_to_string(id, sid));
         } else {
-                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
-
-                sd_bus_error_set(&error,
-                                 "org.freedesktop.DBus.Error.UnknownMethod",
+                r = sd_bus_message_new_method_errorf(
+                                bus, m, &reply,
+                                "org.freedesktop.DBus.Error.UnknownMethod",
                                  "Unknown method '%s' on interface '%s'.", m->member, m->interface);
-
-                r = sd_bus_message_new_method_error(bus, m, &error, &reply);
         }
 
         if (r < 0)
@@ -1837,90 +1875,446 @@ static int process_builtin(sd_bus *bus, sd_bus_message *m) {
         return 1;
 }
 
-static int process_object(sd_bus *bus, sd_bus_message *m) {
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
-        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
-        struct object_callback *c;
+static int node_vtable_get_userdata(
+                sd_bus *bus,
+                const char *path,
+                struct node_vtable *c,
+                void **userdata) {
+
+        void *u;
+        int r;
+
+        assert(bus);
+        assert(path);
+        assert(c);
+        assert(userdata);
+
+        u = c->userdata;
+        if (c->find) {
+                r = c->find(bus, path, c->interface, &u, u);
+                if (r <= 0)
+                        return r;
+        }
+
+        *userdata = u;
+        return 1;
+}
+
+static void *vtable_property_convert_userdata(const sd_bus_vtable *p, void *u) {
+        assert(p);
+
+        return (uint8_t*) u + p->property.offset;
+}
+
+static int vtable_property_get_userdata(
+                sd_bus *bus,
+                const char *path,
+                struct vtable_member *p,
+                void **userdata) {
+
+        void *u;
+        int r;
+
+        assert(bus);
+        assert(path);
+        assert(p);
+        assert(userdata);
+
+        r = node_vtable_get_userdata(bus, path, p->parent, &u);
+        if (r <= 0)
+                return r;
+
+        *userdata = vtable_property_convert_userdata(p->vtable, u);
+        return 1;
+}
+
+static int add_enumerated_to_set(sd_bus *bus, const char *prefix, struct node_enumerator *first, Set *s) {
+        struct node_enumerator *c;
+        int r;
+
+        assert(bus);
+        assert(prefix);
+        assert(s);
+
+        LIST_FOREACH(enumerators, c, first) {
+                char **children = NULL, **k;
+
+                r = c->callback(bus, prefix, &children, c->userdata);
+                if (r < 0)
+                        return r;
+
+                STRV_FOREACH(k, children) {
+                        if (r < 0) {
+                                free(*k);
+                                continue;
+                        }
+
+                        if (!object_path_is_valid(*k) && object_path_startswith(*k, prefix)) {
+                                free(*k);
+                                r = -EINVAL;
+                                continue;
+                        }
+
+                        r = set_consume(s, *k);
+                }
+
+                free(children);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static int add_subtree_to_set(sd_bus *bus, const char *prefix, struct node *n, Set *s) {
+        struct node *i;
+        int r;
+
+        assert(bus);
+        assert(prefix);
+        assert(n);
+        assert(s);
+
+        r = add_enumerated_to_set(bus, prefix, n->enumerators, s);
+        if (r < 0)
+                return r;
+
+        LIST_FOREACH(siblings, i, n->child) {
+                char *t;
+
+                t = strdup(i->path);
+                if (!t)
+                        return -ENOMEM;
+
+                r = set_consume(s, t);
+                if (r < 0 && r != -EEXIST)
+                        return r;
+
+                r = add_subtree_to_set(bus, prefix, i, s);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static int get_child_nodes(sd_bus *bus, const char *prefix, struct node *n, Set **_s) {
+        Set *s = NULL;
+        int r;
+
+        assert(bus);
+        assert(n);
+        assert(_s);
+
+        s = set_new(string_hash_func, string_compare_func);
+        if (!s)
+                return -ENOMEM;
+
+        r = add_subtree_to_set(bus, prefix, n, s);
+        if (r < 0) {
+                set_free_free(s);
+                return r;
+        }
+
+        *_s = s;
+        return 0;
+}
+
+static int node_callbacks_run(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct node_callback *first,
+                bool require_fallback,
+                bool *found_object) {
+
+        struct node_callback *c;
         int r;
-        bool found = false;
-        size_t pl;
 
         assert(bus);
         assert(m);
+        assert(found_object);
 
-        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+        LIST_FOREACH(callbacks, c, first) {
+                if (require_fallback && !c->is_fallback)
+                        continue;
+
+                *found_object = true;
+
+                if (c->last_iteration == bus->iteration_counter)
+                        continue;
+
+                r = sd_bus_message_rewind(m, true);
+                if (r < 0)
+                        return r;
+
+                r = c->callback(bus, m, c->userdata);
+                if (r != 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static int method_callbacks_run(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct vtable_member *c,
+                bool require_fallback,
+                bool *found_object) {
+
+        const char *signature;
+        void *u;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(c);
+        assert(found_object);
+
+        if (require_fallback && !c->parent->is_fallback)
                 return 0;
 
-        if (hashmap_isempty(bus->object_callbacks))
+        r = node_vtable_get_userdata(bus, m->path, c->parent, &u);
+        if (r <= 0)
+                return r;
+
+        *found_object = true;
+
+        r = sd_bus_message_rewind(m, true);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_get_signature(m, true, &signature);
+        if (r < 0)
+                return r;
+
+        if (!streq(c->vtable->method.signature, signature)) {
+                r = sd_bus_reply_method_errorf(bus, m,
+                                               "org.freedesktop.DBus.Error.InvalidArgs",
+                                               "Invalid arguments '%s' to call %s:%s, expecting '%s'.",
+                                               signature, c->interface, c->member, c->vtable->method.signature);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        return c->vtable->method.handler(bus, m, u);
+}
+
+static int property_get_set_callbacks_run(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct vtable_member *c,
+                bool require_fallback,
+                bool is_get,
+                bool *found_object) {
+
+        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        void *u;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(found_object);
+
+        if (require_fallback && !c->parent->is_fallback)
                 return 0;
 
-        pl = strlen(m->path);
+        r = vtable_property_get_userdata(bus, m->path, c, &u);
+        if (r <= 0)
+                return r;
 
-        do {
-                char p[pl+1];
+        *found_object = true;
 
-                bus->object_callbacks_modified = false;
+        r = sd_bus_message_new_method_return(bus, m, &reply);
+        if (r < 0)
+                return r;
 
-                c = hashmap_get(bus->object_callbacks, m->path);
-                if (c && c->last_iteration != bus->iteration_counter) {
+        c->last_iteration = bus->iteration_counter;
 
-                        c->last_iteration = bus->iteration_counter;
+        if (is_get) {
+                r = sd_bus_message_open_container(reply, 'v', c->vtable->property.signature);
+                if (r < 0)
+                        return r;
 
-                        r = sd_bus_message_rewind(m, true);
+                if (c->vtable->property.get) {
+                        r = c->vtable->property.get(bus, m->path, c->interface, c->member, reply, &error, u);
                         if (r < 0)
                                 return r;
+                } else
+                        assert_not_reached("automatic properties not supported yet");
 
-                        r = c->callback(bus, m, c->userdata);
-                        if (r != 0)
+                if (sd_bus_error_is_set(&error)) {
+                        r = sd_bus_reply_method_error(bus, m, &error);
+                        if (r < 0)
                                 return r;
 
-                        found = true;
+                        return 1;
                 }
 
-                /* Look for fallback prefixes */
-                strcpy(p, m->path);
-                for (;;) {
-                        char *e;
+                r = sd_bus_message_close_container(reply);
+                if (r < 0)
+                        return r;
 
-                        if (bus->object_callbacks_modified)
-                                break;
+        } else {
+                if (c->vtable->type != _SD_BUS_VTABLE_WRITABLE_PROPERTY)
+                        sd_bus_error_setf(&error, "org.freedesktop.DBus.Error.PropertyReadOnly", "Property '%s' is not writable.", c->member);
+                else  {
+                        r = sd_bus_message_enter_container(m, 'v', c->vtable->property.signature);
+                        if (r < 0)
+                                return r;
 
-                        e = strrchr(p, '/');
-                        if (e == p || !e)
-                                break;
+                        if (c->vtable->property.set) {
+                                r = c->vtable->property.set(bus, m->path, c->interface, c->member, m, &error, u);
+                                if (r < 0)
+                                        return r;
+                        } else
+                                assert_not_reached("automatic properties not supported yet");
+                }
 
-                        *e = 0;
+                if (sd_bus_error_is_set(&error)) {
+                        r = sd_bus_reply_method_error(bus, m, &error);
+                        if (r < 0)
+                                return r;
 
-                        c = hashmap_get(bus->object_callbacks, p);
-                        if (c && c->last_iteration != bus->iteration_counter && c->is_fallback) {
+                        return 1;
+                }
 
-                                c->last_iteration = bus->iteration_counter;
+                r = sd_bus_message_exit_container(m);
+                if (r < 0)
+                        return r;
+        }
 
-                                r = sd_bus_message_rewind(m, true);
-                                if (r < 0)
-                                        return r;
+        r = sd_bus_send(bus, reply, NULL);
+        if (r < 0)
+                return r;
 
-                                r = c->callback(bus, m, c->userdata);
-                                if (r != 0)
-                                        return r;
+        return 1;
+}
 
-                                found = true;
-                        }
-                }
+static int vtable_append_all_properties(
+                sd_bus *bus,
+                sd_bus_message *reply,
+                const char *path,
+                struct node_vtable *c,
+                void *userdata,
+                sd_bus_error *error) {
 
-        } while (bus->object_callbacks_modified);
+        const sd_bus_vtable *v;
+        int r;
 
-        /* We found some handlers but none wanted to take this, then
-         * return this -- with one exception, we can handle
-         * introspection minimally ourselves */
-        if (!found || sd_bus_message_is_method_call(m, "org.freedesktop.DBus.Introspectable", "Introspect"))
-                return 0;
+        assert(bus);
+        assert(reply);
+        assert(c);
+
+        for (v = c->vtable+1; v->type != _SD_BUS_VTABLE_END; v++) {
+                if (v->type != _SD_BUS_VTABLE_PROPERTY && v->type != _SD_BUS_VTABLE_WRITABLE_PROPERTY)
+                        continue;
+
+                r = sd_bus_message_open_container(reply, 'e', "sv");
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_append(reply, "s", c->interface);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_open_container(reply, 'v', v->property.signature);
+                if (r < 0)
+                        return r;
+
+                r = v->property.get(bus, path, c->interface, v->property.member, reply, error, vtable_property_convert_userdata(v, userdata));
+                if (r < 0)
+                        return r;
+
+                if (sd_bus_error_is_set(error))
+                        return 0;
+
+                r = sd_bus_message_close_container(reply);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_close_container(reply);
+                if (r < 0)
+                        return r;
+        }
 
-        sd_bus_error_set(&error,
-                         "org.freedesktop.DBus.Error.UnknownMethod",
-                         "Unknown method '%s' or interface '%s'.", m->member, m->interface);
+        return 1;
+}
+
+static int property_get_all_callbacks_run(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct node_vtable *first,
+                bool require_fallback,
+                const char *iface,
+                bool *found_object) {
+
+        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+        struct node_vtable *c;
+        bool found_interface = false;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(found_object);
 
-        r = sd_bus_message_new_method_error(bus, m, &error, &reply);
+        r = sd_bus_message_new_method_return(bus, m, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(reply, 'a', "{sv}");
+        if (r < 0)
+                return r;
+
+        LIST_FOREACH(vtables, c, first) {
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+                void *u;
+
+                if (require_fallback && !c->is_fallback)
+                        continue;
+
+                r = node_vtable_get_userdata(bus, m->path, c, &u);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                *found_object = true;
+
+                if (iface && !streq(c->interface, iface))
+                        continue;
+                found_interface = true;
+
+                c->last_iteration = bus->iteration_counter;
+
+                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(bus, m, &error);
+                        if (r < 0)
+                                return r;
+
+                        return 1;
+                }
+        }
+
+        if (!found_interface) {
+                r = sd_bus_reply_method_errorf(
+                                bus, m,
+                                "org.freedesktop.DBus.Error.UnknownInterface",
+                                "Unknown interface '%s'.", iface);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        r = sd_bus_message_close_container(reply);
         if (r < 0)
                 return r;
 
@@ -1931,84 +2325,359 @@ static int process_object(sd_bus *bus, sd_bus_message *m) {
         return 1;
 }
 
-static int process_introspect(sd_bus *bus, sd_bus_message *m) {
+static bool bus_node_with_object_manager(sd_bus *bus, struct node *n) {
+        assert(bus);
+
+        if (n->object_manager)
+                return true;
+
+        if (n->parent)
+                return bus_node_with_object_manager(bus, n->parent);
+
+        return false;
+}
+
+static bool bus_node_exists(sd_bus *bus, struct node *n, const char *path, bool require_fallback) {
+        struct node_vtable *c;
+        struct node_callback *k;
+
+        assert(bus);
+        assert(n);
+
+        if (n->child)
+                return true;
+
+        LIST_FOREACH(callbacks, k, n->callbacks) {
+                if (require_fallback && !k->is_fallback)
+                        continue;
+
+                return true;
+        }
+
+        LIST_FOREACH(vtables, c, n->vtables) {
+
+                if (require_fallback && !c->is_fallback)
+                        continue;
+
+                return true;
+        }
+
+        return !require_fallback && (n->enumerators || n->object_manager);
+
+}
+
+static int process_introspect(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct node *n,
+                bool require_fallback,
+                bool *found_object) {
+
         _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
-        _cleanup_free_ char *introspection = NULL;
         _cleanup_set_free_free_ Set *s = NULL;
-        _cleanup_fclose_ FILE *f = NULL;
-        struct object_callback *c;
-        Iterator i;
-        size_t size = 0;
-        char *node;
+        struct introspect intro;
+        struct node_vtable *c;
+        bool empty;
         int r;
 
         assert(bus);
         assert(m);
+        assert(n);
+        assert(found_object);
 
-        if (!sd_bus_message_is_method_call(m, "org.freedesktop.DBus.Introspectable", "Introspect"))
-                return 0;
+        r = get_child_nodes(bus, m->path, n, &s);
+        if (r < 0)
+                return r;
 
-        if (!m->path)
-                return 0;
+        r = introspect_begin(&intro);
+        if (r < 0)
+                return r;
 
-        s = set_new(string_hash_func, string_compare_func);
-        if (!s)
-                return -ENOMEM;
+        r = introspect_write_default_interfaces(&intro, bus_node_with_object_manager(bus, n));
+        if (r < 0)
+                return r;
 
-        HASHMAP_FOREACH(c, bus->object_callbacks, i) {
-                const char *e;
-                char *a, *p;
+        empty = set_isempty(s);
 
-                if (streq(c->path, "/"))
+        LIST_FOREACH(vtables, c, n->vtables) {
+                void *u;
+
+                if (require_fallback && !c->is_fallback)
                         continue;
 
-                if (streq(m->path, "/"))
-                        e = c->path;
-                else {
-                        e = startswith(c->path, m->path);
-                        if (!e || *e != '/')
-                                continue;
-                }
+                r = node_vtable_get_userdata(bus, m->path, c, &u);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
 
-                a = strdup(e+1);
-                if (!a)
-                        return -ENOMEM;
+                empty = false;
 
-                p = strchr(a, '/');
-                if (p)
-                        *p = 0;
+                r = introspect_write_interface(&intro, c->interface, c->vtable);
+                if (r < 0)
+                        goto finish;
+        }
 
-                r = set_consume(s, a);
-                if (r < 0 && r != -EEXIST)
+        if (empty) {
+                /* Nothing?, let's see if we exist at all, and if not
+                 * refuse to do anything */
+                r = bus_node_exists(bus, n, m->path, require_fallback);
+                if (r < 0)
                         return r;
+
+                if (r == 0)
+                        goto finish;
         }
 
-        f = open_memstream(&introspection, &size);
-        if (!f)
-                return -ENOMEM;
+        *found_object = true;
+
+        r = introspect_write_child_nodes(&intro, s, m->path);
+        if (r < 0)
+                goto finish;
+
+        r = introspect_finish(&intro, bus, m, &reply);
+        if (r < 0)
+                goto finish;
+
+        r = sd_bus_send(bus, reply, NULL);
+        if (r < 0)
+                goto finish;
+
+        r = 1;
+
+finish:
+        introspect_free(&intro);
+        return r;
+}
+
+static int object_manager_serialize_vtable(
+                sd_bus *bus,
+                sd_bus_message *reply,
+                const char *path,
+                struct node_vtable *c,
+                sd_bus_error *error) {
+
+        void *u;
+        int r;
+
+        assert(bus);
+        assert(reply);
+        assert(path);
+        assert(c);
+        assert(error);
+
+        r = node_vtable_get_userdata(bus, path, c, &u);
+        if (r <= 0)
+                return r;
+
+        r = sd_bus_message_open_container(reply, 'e', "sa{sv}");
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(reply, "s", c->interface);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(reply, 'a', "{sv}");
+        if (r < 0)
+                return r;
+
+        r = vtable_append_all_properties(bus, reply, path, c, u, error);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_close_container(reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_close_container(reply);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static int object_manager_serialize_path(
+                sd_bus *bus,
+                sd_bus_message *reply,
+                const char *path,
+                bool require_fallback,
+                sd_bus_error *error) {
+
+        struct node_vtable *i;
+        struct node *n;
+        int r;
+
+        assert(bus);
+        assert(reply);
+        assert(path);
+        assert(error);
+
+        n = hashmap_get(bus->nodes, path);
+        if (!n)
+                return 0;
+
+        r = sd_bus_message_open_container(reply, 'e', "oa{sa{sv}}");
+        if (r < 0)
+                return r;
 
-        fputs(SD_BUS_INTROSPECT_DOCTYPE, f);
-        fputs("<node>\n", f);
-        fputs(SD_BUS_INTROSPECT_INTERFACE_PEER, f);
-        fputs(SD_BUS_INTROSPECT_INTERFACE_INTROSPECTABLE, f);
+        r = sd_bus_message_append(reply, "o", path);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(reply, 'a', "{sa{sv}}");
+        if (r < 0)
+                return r;
 
-        while ((node = set_steal_first(s))) {
-                fprintf(f, " <node name=\"%s\"/>\n", node);
-                free(node);
+        LIST_FOREACH(vtables, i, n->vtables) {
+
+                if (require_fallback && !i->is_fallback)
+                        continue;
+
+                r = object_manager_serialize_vtable(bus, reply, path, i, error);
+                if (r < 0)
+                        return r;
+                if (sd_bus_error_is_set(error))
+                        return 0;
         }
 
-        fputs("</node>\n", f);
+        r = sd_bus_message_close_container(reply);
+        if (r < 0)
+                return r;
 
-        fflush(f);
+        r = sd_bus_message_close_container(reply);
+        if (r < 0)
+                return r;
 
-        if (ferror(f))
-                return -ENOMEM;
+        return 1;
+}
+
+static int object_manager_serialize_path_and_fallbacks(
+                sd_bus *bus,
+                sd_bus_message *reply,
+                const char *path,
+                sd_bus_error *error) {
+
+        size_t pl;
+        int r;
+
+        assert(bus);
+        assert(reply);
+        assert(path);
+        assert(error);
+
+        /* First, add all vtables registered for this path */
+        r = object_manager_serialize_path(bus, reply, path, false, error);
+        if (r < 0)
+                return r;
+        if (sd_bus_error_is_set(error))
+                return 0;
+
+        /* Second, add fallback vtables registered for any of the prefixes */
+        pl = strlen(path);
+        if (pl > 1) {
+                char p[pl + 1];
+                strcpy(p, path);
+
+                for (;;) {
+                        char *e;
+
+                        e = strrchr(p, '/');
+                        if (e == p || !e)
+                                break;
+
+                        *e = 0;
+
+                        r = object_manager_serialize_path(bus, reply, p, true, error);
+                        if (r < 0)
+                                return r;
+
+                        if (sd_bus_error_is_set(error))
+                                return 0;
+                }
+        }
+
+        return 0;
+}
+
+static int process_get_managed_objects(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct node *n,
+                bool require_fallback,
+                bool *found_object) {
+
+        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+        _cleanup_set_free_free_ Set *s = NULL;
+        bool empty;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(n);
+        assert(found_object);
+
+        if (!bus_node_with_object_manager(bus, n))
+                return 0;
+
+        r = get_child_nodes(bus, m->path, n, &s);
+        if (r < 0)
+                return r;
 
         r = sd_bus_message_new_method_return(bus, m, &reply);
         if (r < 0)
                 return r;
 
-        r = sd_bus_message_append(reply, "s", introspection);
+        r = sd_bus_message_open_container(reply, 'a', "{oa{sa{sv}}}");
+        if (r < 0)
+                return r;
+
+        empty = set_isempty(s);
+        if (empty) {
+                struct node_vtable *c;
+
+                /* Hmm, so we have no children? Then let's check
+                 * whether we exist at all, i.e. whether at least one
+                 * vtable exists. */
+
+                LIST_FOREACH(vtables, c, n->vtables) {
+
+                        if (require_fallback && !c->is_fallback)
+                                continue;
+
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                continue;
+
+                        empty = false;
+                        break;
+                }
+
+                if (empty)
+                        return 0;
+        } else {
+                Iterator i;
+                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(bus, m, &error);
+                                if (r < 0)
+                                        return r;
+
+                                return 1;
+                        }
+                }
+        }
+
+        r = sd_bus_message_close_container(reply);
         if (r < 0)
                 return r;
 
@@ -2019,6 +2688,182 @@ static int process_introspect(sd_bus *bus, sd_bus_message *m) {
         return 1;
 }
 
+static int object_find_and_run(sd_bus *bus, sd_bus_message *m, const char *p, bool require_fallback, bool *found_object) {
+        struct node *n;
+        struct vtable_member vtable_key, *v;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(p);
+        assert(found_object);
+
+        n = hashmap_get(bus->nodes, p);
+        if (!n)
+                return 0;
+
+        /* First, try object callbacks */
+        r = node_callbacks_run(bus, m, n->callbacks, require_fallback, found_object);
+        if (r != 0)
+                return r;
+
+        if (!m->interface || !m->member)
+                return 0;
+
+        /* Then, look for a known method */
+        vtable_key.path = (char*) p;
+        vtable_key.interface = m->interface;
+        vtable_key.member = m->member;
+
+        v = hashmap_get(bus->vtable_methods, &vtable_key);
+        if (v) {
+                r = method_callbacks_run(bus, m, v, require_fallback, found_object);
+                if (r != 0)
+                        return r;
+        }
+
+        /* Then, look for a known property */
+        if (streq(m->interface, "org.freedesktop.DBus.Properties")) {
+                bool get = false;
+
+                get = streq(m->member, "Get");
+
+                if (get || streq(m->member, "Set")) {
+
+                        r = sd_bus_message_rewind(m, true);
+                        if (r < 0)
+                                return r;
+
+                        vtable_key.path = (char*) p;
+
+                        r = sd_bus_message_read(m, "ss", &vtable_key.interface, &vtable_key.member);
+                        if (r < 0)
+                                return r;
+
+                        v = hashmap_get(bus->vtable_properties, &vtable_key);
+                        if (v) {
+                                r = property_get_set_callbacks_run(bus, m, v, require_fallback, get, found_object);
+                                if (r != 0)
+                                        return r;
+                        }
+
+                } else if (streq(m->member, "GetAll")) {
+                        const char *iface;
+
+                        r = sd_bus_message_rewind(m, true);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_read(m, "s", &iface);
+                        if (r < 0)
+                                return r;
+
+                        if (iface[0] == 0)
+                                iface = NULL;
+
+                        r = property_get_all_callbacks_run(bus, m, n->vtables, require_fallback, iface, found_object);
+                        if (r != 0)
+                                return r;
+                }
+
+        } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus.Introspectable", "Introspect")) {
+
+                r = process_introspect(bus, m, n, require_fallback, found_object);
+                if (r != 0)
+                        return r;
+
+        } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus.ObjectManager", "GetManagedObjects")) {
+
+                r = process_get_managed_objects(bus, m, n, require_fallback, found_object);
+                if (r != 0)
+                        return r;
+        }
+
+        if (!*found_object) {
+                r = bus_node_exists(bus, n, m->path, require_fallback);
+                if (r < 0)
+                        return r;
+
+                if (r > 0)
+                        *found_object = true;
+        }
+
+        return 0;
+}
+
+static int process_object(sd_bus *bus, sd_bus_message *m) {
+        int r;
+        size_t pl;
+        bool found_object = false;
+
+        assert(bus);
+        assert(m);
+
+        if (m->header->type != SD_BUS_MESSAGE_TYPE_METHOD_CALL)
+                return 0;
+
+        if (!m->path)
+                return 0;
+
+        if (hashmap_isempty(bus->nodes))
+                return 0;
+
+        pl = strlen(m->path);
+        do {
+                char p[pl+1];
+
+                bus->nodes_modified = false;
+
+                r = object_find_and_run(bus, m, m->path, false, &found_object);
+                if (r != 0)
+                        return r;
+
+                /* Look for fallback prefixes */
+                strcpy(p, m->path);
+                for (;;) {
+                        char *e;
+
+                        if (streq(p, "/"))
+                                break;
+
+                        if (bus->nodes_modified)
+                                break;
+
+                        e = strrchr(p, '/');
+                        assert(e);
+                        if (e == p)
+                                *(e+1) = 0;
+                        else
+                                *e = 0;
+
+                        r = object_find_and_run(bus, m, p, true, &found_object);
+                        if (r != 0)
+                                return r;
+                }
+
+        } while (bus->nodes_modified);
+
+        if (!found_object)
+                return 0;
+
+        if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus.Properties", "Get") ||
+            sd_bus_message_is_method_call(m, "org.freedesktop.DBus.Properties", "Set"))
+                r = sd_bus_reply_method_errorf(
+                                bus, m,
+                                "org.freedesktop.DBus.Error.UnknownProperty",
+                                "Unknown property or interface.");
+        else
+                r = sd_bus_reply_method_errorf(
+                                bus, m,
+                                "org.freedesktop.DBus.Error.UnknownMethod",
+                                "Unknown method '%s' or interface '%s'.", m->member, m->interface);
+
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
 static int process_message(sd_bus *bus, sd_bus_message *m) {
         int r;
 
@@ -2047,11 +2892,7 @@ static int process_message(sd_bus *bus, sd_bus_message *m) {
         if (r != 0)
                 return r;
 
-        r = process_object(bus, m);
-        if (r != 0)
-                return r;
-
-        return process_introspect(bus, m);
+        return process_object(bus, m);
 }
 
 static int process_running(sd_bus *bus, sd_bus_message **ret) {
@@ -2090,16 +2931,11 @@ static int process_running(sd_bus *bus, sd_bus_message **ret) {
         }
 
         if (m->header->type == SD_BUS_MESSAGE_TYPE_METHOD_CALL) {
-                _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
-                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
-
-                sd_bus_error_set(&error, "org.freedesktop.DBus.Error.UnknownObject", "Unknown object '%s'.", m->path);
-
-                r = sd_bus_message_new_method_error(bus, m, &error, &reply);
-                if (r < 0)
-                        return r;
 
-                r = sd_bus_send(bus, reply, NULL);
+                r = sd_bus_reply_method_errorf(
+                                bus, m,
+                                "org.freedesktop.DBus.Error.UnknownObject",
+                                "Unknown object '%s'.", m->path);
                 if (r < 0)
                         return r;
         }
@@ -2305,52 +3141,128 @@ int sd_bus_remove_filter(sd_bus *bus, sd_bus_message_handler_t callback, void *u
         return 0;
 }
 
+static struct node *bus_node_allocate(sd_bus *bus, const char *path) {
+        struct node *n, *parent;
+        const char *e;
+        char *s, *p;
+        int r;
+
+        assert(bus);
+        assert(path);
+        assert(path[0] == '/');
+
+        n = hashmap_get(bus->nodes, path);
+        if (n)
+                return n;
+
+        r = hashmap_ensure_allocated(&bus->nodes, string_hash_func, string_compare_func);
+        if (r < 0)
+                return NULL;
+
+        s = strdup(path);
+        if (!s)
+                return NULL;
+
+        if (streq(path, "/"))
+                parent = NULL;
+        else {
+                e = strrchr(path, '/');
+                assert(e);
+
+                p = strndupa(path, MAX(1, path - e));
+
+                parent = bus_node_allocate(bus, p);
+                if (!parent) {
+                        free(s);
+                        return NULL;
+                }
+        }
+
+        n = new0(struct node, 1);
+        if (!n)
+                return NULL;
+
+        n->parent = parent;
+        n->path = s;
+
+        r = hashmap_put(bus->nodes, s, n);
+        if (r < 0) {
+                free(s);
+                free(n);
+                return NULL;
+        }
+
+        if (parent)
+                LIST_PREPEND(struct node, siblings, parent->child, n);
+
+        return n;
+}
+
+static void bus_node_gc(sd_bus *b, struct node *n) {
+        assert(b);
+
+        if (!n)
+                return;
+
+        if (n->child ||
+            n->callbacks ||
+            n->vtables ||
+            n->enumerators ||
+            n->object_manager)
+                return;
+
+        assert(hashmap_remove(b->nodes, n->path) == n);
+
+        if (n->parent)
+                LIST_REMOVE(struct node, siblings, n->parent->child, n);
+
+        free(n->path);
+        bus_node_gc(b, n->parent);
+        free(n);
+}
+
 static int bus_add_object(
-                sd_bus *bus,
+                sd_bus *b,
                 bool fallback,
                 const char *path,
                 sd_bus_message_handler_t callback,
                 void *userdata) {
 
-        struct object_callback *c;
+        struct node_callback *c;
+        struct node *n;
         int r;
 
-        if (!bus)
+        if (!b)
                 return -EINVAL;
-        if (!path)
+        if (!object_path_is_valid(path))
                 return -EINVAL;
         if (!callback)
                 return -EINVAL;
-        if (bus_pid_changed(bus))
+        if (bus_pid_changed(b))
                 return -ECHILD;
 
-        r = hashmap_ensure_allocated(&bus->object_callbacks, string_hash_func, string_compare_func);
-        if (r < 0)
-                return r;
-
-        c = new0(struct object_callback, 1);
-        if (!c)
+        n = bus_node_allocate(b, path);
+        if (!n)
                 return -ENOMEM;
 
-        c->path = strdup(path);
-        if (!c->path) {
-                free(c);
-                return -ENOMEM;
+        c = new0(struct node_callback, 1);
+        if (!c) {
+                r = -ENOMEM;
+                goto fail;
         }
 
+        c->node = n;
         c->callback = callback;
         c->userdata = userdata;
         c->is_fallback = fallback;
 
-        bus->object_callbacks_modified = true;
-        r = hashmap_put(bus->object_callbacks, c->path, c);
-        if (r < 0) {
-                free(c->path);
-                free(c);
-                return r;
-        }
-
+        LIST_PREPEND(struct node_callback, callbacks, n->callbacks, c);
         return 0;
+
+fail:
+        free(c);
+        bus_node_gc(b, n);
+        return r;
 }
 
 static int bus_remove_object(
@@ -2360,30 +3272,33 @@ static int bus_remove_object(
                 sd_bus_message_handler_t callback,
                 void *userdata) {
 
-        struct object_callback *c;
+        struct node_callback *c;
+        struct node *n;
 
         if (!bus)
                 return -EINVAL;
-        if (!path)
+        if (!object_path_is_valid(path))
                 return -EINVAL;
         if (!callback)
                 return -EINVAL;
         if (bus_pid_changed(bus))
                 return -ECHILD;
 
-        c = hashmap_get(bus->object_callbacks, path);
-        if (!c)
+        n = hashmap_get(bus->nodes, path);
+        if (!n)
                 return 0;
 
-        if (c->callback != callback || c->userdata != userdata || c->is_fallback != fallback)
+        LIST_FOREACH(callbacks, c, n->callbacks)
+                if (c->callback == callback && c->userdata == userdata && c->is_fallback == fallback)
+                        break;
+        if (!c)
                 return 0;
 
-        bus->object_callbacks_modified = true;
-        assert_se(c == hashmap_remove(bus->object_callbacks, c->path));
-
-        free(c->path);
+        LIST_REMOVE(struct node_callback, callbacks, n->callbacks, c);
         free(c);
 
+        bus_node_gc(bus, n);
+
         return 1;
 }
 
@@ -2605,6 +3520,40 @@ int sd_bus_reply_method_error(
         return sd_bus_send(bus, m, NULL);
 }
 
+int sd_bus_reply_method_errorf(
+                sd_bus *bus,
+                sd_bus_message *call,
+                const char *name,
+                const char *format,
+                ...) {
+
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        char *n, *m;
+        va_list ap;
+        int r;
+
+        n = strdup(name);
+        if (!n)
+                return -ENOMEM;
+
+        if (format) {
+                va_start(ap, format);
+                r = vasprintf(&m, format, ap);
+                va_end(ap);
+
+                if (r < 0) {
+                        free(n);
+                        return -ENOMEM;
+                }
+        }
+
+        error.name = n;
+        error.message = m;
+        error.need_free = true;
+
+        return sd_bus_reply_method_error(bus, call, &error);
+}
+
 bool bus_pid_changed(sd_bus *bus) {
         assert(bus);
 
@@ -2613,3 +3562,711 @@ bool bus_pid_changed(sd_bus *bus) {
 
         return bus->original_pid != getpid();
 }
+
+static void free_node_vtable(sd_bus *bus, struct node_vtable *w) {
+        assert(bus);
+
+        if (!w)
+                return;
+
+        if (w->interface && w->node && w->vtable) {
+                const sd_bus_vtable *v;
+
+                for (v = w->vtable; v->type != _SD_BUS_VTABLE_END; w++) {
+                        struct vtable_member *x = NULL;
+
+                        switch (v->type) {
+
+                        case _SD_BUS_VTABLE_METHOD: {
+                                struct vtable_member key;
+
+                                key.path = w->node->path;
+                                key.interface = w->interface;
+                                key.member = v->method.member;
+
+                                x = hashmap_remove(bus->vtable_methods, &key);
+                                break;
+                        }
+
+                        case _SD_BUS_VTABLE_PROPERTY:
+                        case _SD_BUS_VTABLE_WRITABLE_PROPERTY: {
+                                struct vtable_member key;
+
+                                key.path = w->node->path;
+                                key.interface = w->interface;
+                                key.member = v->property.member;
+                                x = hashmap_remove(bus->vtable_properties, &key);
+                                break;
+                        }}
+
+                        free(x);
+                }
+        }
+
+        free(w->interface);
+        free(w);
+}
+
+static unsigned vtable_member_hash_func(const void *a) {
+        const struct vtable_member *m = a;
+
+        return
+                string_hash_func(m->path) ^
+                string_hash_func(m->interface) ^
+                string_hash_func(m->member);
+}
+
+static int vtable_member_compare_func(const void *a, const void *b) {
+        const struct vtable_member *x = a, *y = b;
+        int r;
+
+        r = strcmp(x->path, y->path);
+        if (r != 0)
+                return r;
+
+        r = strcmp(x->interface, y->interface);
+        if (r != 0)
+                return r;
+
+        return strcmp(x->member, y->member);
+}
+
+static int add_object_vtable_internal(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const sd_bus_vtable *vtable,
+                bool fallback,
+                sd_bus_object_find_t find,
+                void *userdata) {
+
+        struct node_vtable *c, *i;
+        const sd_bus_vtable *v;
+        struct node *n;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!object_path_is_valid(path))
+                return -EINVAL;
+        if (!interface_name_is_valid(interface))
+                return -EINVAL;
+        if (!vtable || vtable[0].type != _SD_BUS_VTABLE_START || vtable[0].start.element_size != sizeof(struct sd_bus_vtable))
+                return -EINVAL;
+        if (bus_pid_changed(bus))
+                return -ECHILD;
+
+        r = hashmap_ensure_allocated(&bus->vtable_methods, vtable_member_hash_func, vtable_member_compare_func);
+        if (r < 0)
+                return r;
+
+        r = hashmap_ensure_allocated(&bus->vtable_properties, vtable_member_hash_func, vtable_member_compare_func);
+        if (r < 0)
+                return r;
+
+        n = bus_node_allocate(bus, path);
+        if (!n)
+                return -ENOMEM;
+
+        LIST_FOREACH(vtables, i, n->vtables) {
+                if (streq(i->interface, interface)) {
+                        r = -EEXIST;
+                        goto fail;
+                }
+
+                if (i->is_fallback != fallback) {
+                        r = -EPROTOTYPE;
+                        goto fail;
+                }
+        }
+
+        c = new0(struct node_vtable, 1);
+        if (!c) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        c->node = n;
+        c->is_fallback = fallback;
+        c->vtable = vtable;
+        c->userdata = userdata;
+        c->find = find;
+
+        c->interface = strdup(interface);
+        if (!c->interface) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        for (v = c->vtable+1; v->type != _SD_BUS_VTABLE_END; v++) {
+
+                switch (v->type) {
+
+                case _SD_BUS_VTABLE_METHOD: {
+                        struct vtable_member *m;
+
+                        if (!member_name_is_valid(v->method.member) ||
+                            !signature_is_valid(v->method.signature, false) ||
+                            !signature_is_valid(v->method.result, false) ||
+                            !v->method.handler ||
+                            v->flags & (SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE|SD_BUS_VTABLE_PROPERTY_INVALIDATE_ONLY)) {
+                                r = -EINVAL;
+                                goto fail;
+                        }
+
+                        m = new0(struct vtable_member, 1);
+                        if (!m) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+
+                        m->parent = c;
+                        m->path = n->path;
+                        m->interface = c->interface;
+                        m->member = v->method.member;
+                        m->vtable = v;
+
+                        r = hashmap_put(bus->vtable_methods, m, m);
+                        if (r < 0) {
+                                free(m);
+                                goto fail;
+                        }
+
+                        break;
+                }
+
+                case _SD_BUS_VTABLE_PROPERTY:
+                case _SD_BUS_VTABLE_WRITABLE_PROPERTY: {
+                        struct vtable_member *m;
+
+                        if (!member_name_is_valid(v->property.member) ||
+                            !signature_is_single(v->property.signature, false) ||
+                            v->flags & SD_BUS_VTABLE_METHOD_NO_REPLY ||
+                            (v->flags & SD_BUS_VTABLE_PROPERTY_INVALIDATE_ONLY && !(v->flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE))) {
+                                r = -EINVAL;
+                                goto fail;
+                        }
+
+
+                        m = new0(struct vtable_member, 1);
+                        if (!m) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+
+                        m->parent = c;
+                        m->path = n->path;
+                        m->interface = c->interface;
+                        m->member = v->property.member;
+                        m->vtable = v;
+
+                        r = hashmap_put(bus->vtable_properties, m, m);
+                        if (r < 0) {
+                                free(m);
+                                goto fail;
+                        }
+
+                        break;
+                }
+
+                case _SD_BUS_VTABLE_SIGNAL:
+
+                        if (!member_name_is_valid(v->signal.member) ||
+                            !signature_is_single(v->signal.signature, false)) {
+                                r = -EINVAL;
+                                goto fail;
+                        }
+
+                        break;
+
+                default:
+                        r = -EINVAL;
+                        goto fail;
+                }
+        }
+
+        LIST_PREPEND(struct node_vtable, vtables, n->vtables, c);
+        return 0;
+
+fail:
+        if (c)
+                free_node_vtable(bus, c);
+
+        bus_node_gc(bus, n);
+        return 0;
+}
+
+static int remove_object_vtable_internal(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                bool fallback) {
+
+        struct node_vtable *c;
+        struct node *n;
+
+        if (!bus)
+                return -EINVAL;
+        if (!object_path_is_valid(path))
+                return -EINVAL;
+        if (!interface_name_is_valid(interface))
+                return -EINVAL;
+        if (bus_pid_changed(bus))
+                return -ECHILD;
+
+        n = hashmap_get(bus->nodes, path);
+        if (!n)
+                return 0;
+
+        LIST_FOREACH(vtables, c, n->vtables)
+                if (streq(c->interface, interface) && c->is_fallback == fallback)
+                        break;
+
+        if (!c)
+                return 0;
+
+        LIST_REMOVE(struct node_vtable, vtables, n->vtables, c);
+
+        free_node_vtable(bus, c);
+        return 1;
+}
+
+int sd_bus_add_object_vtable(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const sd_bus_vtable *vtable,
+                void *userdata) {
+
+        return add_object_vtable_internal(bus, path, interface, vtable, false, NULL, userdata);
+}
+
+int sd_bus_remove_object_vtable(
+                sd_bus *bus,
+                const char *path,
+                const char *interface) {
+
+        return remove_object_vtable_internal(bus, path, interface, false);
+}
+
+int sd_bus_add_fallback_vtable(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const sd_bus_vtable *vtable,
+                sd_bus_object_find_t find,
+                void *userdata) {
+
+        return add_object_vtable_internal(bus, path, interface, vtable, true, find, userdata);
+}
+
+int sd_bus_remove_fallback_vtable(
+                sd_bus *bus,
+                const char *path,
+                const char *interface) {
+
+        return remove_object_vtable_internal(bus, path, interface, true);
+}
+
+int sd_bus_add_node_enumerator(
+                sd_bus *bus,
+                const char *path,
+                sd_bus_node_enumerator_t callback,
+                void *userdata) {
+
+        struct node_enumerator *c;
+        struct node *n;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!object_path_is_valid(path))
+                return -EINVAL;
+        if (!callback)
+                return -EINVAL;
+        if (bus_pid_changed(bus))
+                return -ECHILD;
+
+        n = bus_node_allocate(bus, path);
+        if (!n)
+                return -ENOMEM;
+
+        c = new0(struct node_enumerator, 1);
+        if (!c) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        c->node = n;
+        c->callback = callback;
+        c->userdata = userdata;
+
+        LIST_PREPEND(struct node_enumerator, enumerators, n->enumerators, c);
+        return 0;
+
+fail:
+        free(c);
+        bus_node_gc(bus, n);
+        return r;
+}
+
+int sd_bus_remove_node_enumerator(
+                sd_bus *bus,
+                const char *path,
+                sd_bus_node_enumerator_t callback,
+                void *userdata) {
+
+        struct node_enumerator *c;
+        struct node *n;
+
+        if (!bus)
+                return -EINVAL;
+        if (!object_path_is_valid(path))
+                return -EINVAL;
+        if (!callback)
+                return -EINVAL;
+        if (bus_pid_changed(bus))
+                return -ECHILD;
+
+        n = hashmap_get(bus->nodes, path);
+        if (!n)
+                return 0;
+
+        LIST_FOREACH(enumerators, c, n->enumerators)
+                if (c->callback == callback && c->userdata == userdata)
+                        break;
+
+        if (!c)
+                return 0;
+
+        LIST_REMOVE(struct node_enumerator, enumerators, n->enumerators, c);
+        free(c);
+
+        bus_node_gc(bus, n);
+
+        return 1;
+}
+
+static int emit_properties_changed_on_interface(
+                sd_bus *bus,
+                const char *prefix,
+                const char *path,
+                const char *interface,
+                bool require_fallback,
+                char **names) {
+
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        bool has_invalidating = false;
+        struct vtable_member key;
+        struct node_vtable *c;
+        struct node *n;
+        char **property;
+        void *u;
+        int r;
+
+        assert(bus);
+        assert(path);
+        assert(interface);
+
+        n = hashmap_get(bus->nodes, prefix);
+        if (!n)
+                return 0;
+
+        LIST_FOREACH(vtables, c, n->vtables) {
+                if (require_fallback && !c->is_fallback)
+                        continue;
+
+                if (streq(c->interface, interface))
+                        break;
+
+                r = node_vtable_get_userdata(bus, path, c, &u);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        break;
+        }
+
+        if (!c)
+                return 0;
+
+        r = sd_bus_message_new_signal(bus, path, "org.freedesktop.DBus", "PropertiesChanged", &m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "s", interface);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(m, 'a', "{sv}");
+        if (r < 0)
+                return r;
+
+        key.path = prefix;
+        key.interface = interface;
+
+        STRV_FOREACH(property, names) {
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+                struct vtable_member *v;
+
+                key.member = *property;
+                v = hashmap_get(bus->vtable_properties, &key);
+                if (!v)
+                        return -ENOENT;
+
+                assert(c == v->parent);
+
+                if (!(v->vtable->flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE))
+                        return -EDOM;
+                if (v->vtable->flags & SD_BUS_VTABLE_PROPERTY_INVALIDATE_ONLY) {
+                        has_invalidating = true;
+                        continue;
+                }
+
+                r = sd_bus_message_open_container(m, 'e', "sv");
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_append(m, "s", *n);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_open_container(m, 'v', v->vtable->property.signature);
+                if (r < 0)
+                        return r;
+
+                r = v->vtable->property.get(bus, m->path, interface, *property, m, &error, u);
+                if (r < 0)
+                        return r;
+
+                if (sd_bus_error_is_set(&error))
+                        return bus_error_to_errno(&error);
+
+                r = sd_bus_message_close_container(m);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_close_container(m);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_bus_message_close_container(m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(m, 'a', "s");
+        if (r < 0)
+                return r;
+
+        if (has_invalidating) {
+                STRV_FOREACH(property, names) {
+                        struct vtable_member *v;
+
+                        key.member = *property;
+                        assert_se(v = hashmap_get(bus->vtable_properties, &key));
+                        assert(c == v->parent);
+
+                        if (!(v->vtable->flags & SD_BUS_VTABLE_PROPERTY_INVALIDATE_ONLY))
+                                continue;
+
+                        r = sd_bus_message_append(m, "s", *property);
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        r = sd_bus_message_close_container(m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send(bus, m, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+int sd_bus_emit_properties_changed_strv(sd_bus *bus, const char *path, const char *interface, char **names) {
+        size_t pl;
+        int r;
+
+        if (!bus)
+                return -EINVAL;
+        if (!object_path_is_valid(path))
+                return -EINVAL;
+        if (!interface_name_is_valid(interface))
+                return -EINVAL;
+
+        r = emit_properties_changed_on_interface(bus, path, path, interface, false, names);
+        if (r != 0)
+                return r;
+
+        pl = strlen(path);
+        if (pl > 1 ) {
+                char p[pl+1];
+
+                strcpy(p, path);
+                for (;;) {
+                        char *e;
+
+                        if (streq(p, "/"))
+                                break;
+
+                        e = strrchr(p, '/');
+                        assert(e);
+                        if (e == p)
+                                *(e+1) = 0;
+                        else
+                                *e = 0;
+
+                        r = emit_properties_changed_on_interface(bus, p, path, interface, true, names);
+                        if (r != 0)
+                                return r;
+                }
+        }
+
+        return -ENOENT;
+}
+
+int sd_bus_emit_properties_changed(sd_bus *bus, const char *path, const char *interface, const char *name, ...)  {
+        _cleanup_strv_free_ char **names = NULL;
+        va_list ap;
+
+        va_start(ap, name);
+        names = strv_new_ap(name, ap);
+        va_end(ap);
+
+        if (!names)
+                return -ENOMEM;
+
+        return sd_bus_emit_properties_changed_strv(bus, path, interface, names);
+}
+
+int sd_bus_emit_interfaces_added(sd_bus *bus, const char *path, const char *interfaces, ...) {
+        return -ENOSYS;
+}
+
+int sd_bus_emit_interfaces_removed(sd_bus *bus, const char *path, const char *interfaces, ...) {
+        return -ENOSYS;
+}
+
+int sd_bus_get_property(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_error *error,
+                sd_bus_message **reply,
+                const char *type) {
+
+        sd_bus_message *rep = NULL;
+        int r;
+
+        if (interface && !interface_name_is_valid(interface))
+                return -EINVAL;
+        if (!member_name_is_valid(member))
+                return -EINVAL;
+        if (!signature_is_single(type, false))
+                return -EINVAL;
+        if (!reply)
+                return -EINVAL;
+
+        r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &rep, "ss", strempty(interface), member);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_enter_container(rep, 'v', type);
+        if (r < 0) {
+                sd_bus_message_unref(rep);
+                return r;
+        }
+
+        *reply = rep;
+        return 0;
+}
+
+int sd_bus_set_property(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_error *error,
+                const char *type, ...) {
+
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        va_list ap;
+        int r;
+
+        if (interface && !interface_name_is_valid(interface))
+                return -EINVAL;
+        if (!member_name_is_valid(member))
+                return -EINVAL;
+        if (!signature_is_single(type, false))
+                return -EINVAL;
+
+        r = sd_bus_message_new_method_call(bus, destination, path, "org.freedesktop.DBus.Properties", "Set", &m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "ss", strempty(interface), member);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(m, 'v', type);
+        if (r < 0)
+                return r;
+
+        va_start(ap, type);
+        r = bus_message_append_ap(m, type, ap);
+        va_end(ap);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_close_container(m);
+        if (r < 0)
+                return r;
+
+        return sd_bus_send_with_reply_and_block(bus, m, 0, error, NULL);
+}
+
+int sd_bus_add_object_manager(sd_bus *bus, const char *path) {
+        struct node *n;
+
+        if (!bus)
+                return -EINVAL;
+        if (!object_path_is_valid(path))
+                return -EINVAL;
+        if (bus_pid_changed(bus))
+                return -ECHILD;
+
+        n = bus_node_allocate(bus, path);
+        if (!n)
+                return -ENOMEM;
+
+        n->object_manager = true;
+        return 0;
+}
+
+int sd_bus_remove_object_manager(sd_bus *bus, const char *path) {
+        struct node *n;
+
+        if (!bus)
+                return -EINVAL;
+        if (!object_path_is_valid(path))
+                return -EINVAL;
+        if (bus_pid_changed(bus))
+                return -ECHILD;
+
+        n = hashmap_get(bus->nodes, path);
+        if (!n)
+                return 0;
+
+        if (!n->object_manager)
+                return 0;
+
+        n->object_manager = false;
+        bus_node_gc(bus, n);
+        return 1;
+}