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authorLennart Poettering <lennart@poettering.net>2013-10-14 21:58:06 +0200
committerLennart Poettering <lennart@poettering.net>2013-10-14 21:58:06 +0200
commit68313d3dfa2082dae8a06643d639e0200afc19fc (patch)
tree6deaaeef1ebd1ac04ac9a70fba5f644fdbbabc45 /src/libsystemd-bus
parent8ce2afd6347dcf01e33fe1ff257e2b0fffa8edfe (diff)
bus: properly handle if new objects are installed in the node tree while we are dispatching to one
Diffstat (limited to 'src/libsystemd-bus')
-rw-r--r--src/libsystemd-bus/bus-objects.c190
-rw-r--r--src/libsystemd-bus/test-bus-objects.c8
2 files changed, 155 insertions, 43 deletions
diff --git a/src/libsystemd-bus/bus-objects.c b/src/libsystemd-bus/bus-objects.c
index 9142fab37a..4091490c5e 100644
--- a/src/libsystemd-bus/bus-objects.c
+++ b/src/libsystemd-bus/bus-objects.c
@@ -77,6 +77,8 @@ static int vtable_property_get_userdata(
r = node_vtable_get_userdata(bus, path, p->parent, &u);
if (r <= 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
*userdata = vtable_property_convert_userdata(p->vtable, u);
return 1;
@@ -98,6 +100,9 @@ static int add_enumerated_to_set(
LIST_FOREACH(enumerators, c, first) {
char **children = NULL, **k;
+ if (bus->nodes_modified)
+ return 0;
+
r = c->callback(bus, prefix, &children, c->userdata);
if (r < 0)
return r;
@@ -142,6 +147,8 @@ static int add_subtree_to_set(
r = add_enumerated_to_set(bus, prefix, n->enumerators, s);
if (r < 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
LIST_FOREACH(siblings, i, n->child) {
char *t;
@@ -157,6 +164,8 @@ static int add_subtree_to_set(
r = add_subtree_to_set(bus, prefix, i, s);
if (r < 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
}
return 0;
@@ -205,6 +214,9 @@ static int node_callbacks_run(
assert(found_object);
LIST_FOREACH(callbacks, c, first) {
+ if (bus->nodes_modified)
+ return 0;
+
if (require_fallback && !c->is_fallback)
continue;
@@ -213,6 +225,8 @@ static int node_callbacks_run(
if (c->last_iteration == bus->iteration_counter)
continue;
+ c->last_iteration = bus->iteration_counter;
+
r = sd_bus_message_rewind(m, true);
if (r < 0)
return r;
@@ -247,9 +261,16 @@ static int method_callbacks_run(
r = node_vtable_get_userdata(bus, m->path, c->parent, &u);
if (r <= 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
*found_object = true;
+ if (c->last_iteration == bus->iteration_counter)
+ return 0;
+
+ c->last_iteration = bus->iteration_counter;
+
r = sd_bus_message_rewind(m, true);
if (r < 0)
return r;
@@ -412,6 +433,8 @@ static int property_get_set_callbacks_run(
r = vtable_property_get_userdata(bus, m->path, c, &u);
if (r <= 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
*found_object = true;
@@ -419,9 +442,14 @@ static int property_get_set_callbacks_run(
if (r < 0)
return r;
- c->last_iteration = bus->iteration_counter;
-
if (is_get) {
+ /* Note that we do not protect against reexecution
+ * here (using the last_iteration check, see below),
+ * should the node tree have changed and we got called
+ * again. We assume that property Get() calls are
+ * ultimately without side-effects or if they aren't
+ * then at least idempotent. */
+
r = sd_bus_message_open_container(reply, 'v', c->vtable->x.property.signature);
if (r < 0)
return r;
@@ -438,6 +466,9 @@ static int property_get_set_callbacks_run(
return 1;
}
+ if (bus->nodes_modified)
+ return 0;
+
r = sd_bus_message_close_container(reply);
if (r < 0)
return r;
@@ -446,6 +477,15 @@ static int property_get_set_callbacks_run(
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 {
+ /* Avoid that we call the set routine more
+ * than once if the processing of this message
+ * got restarted because the node tree
+ * changed. */
+ if (c->last_iteration == bus->iteration_counter)
+ return 0;
+
+ c->last_iteration = bus->iteration_counter;
+
r = sd_bus_message_enter_container(m, 'v', c->vtable->x.property.signature);
if (r < 0)
return r;
@@ -463,6 +503,9 @@ static int property_get_set_callbacks_run(
return 1;
}
+ if (bus->nodes_modified)
+ return 0;
+
r = sd_bus_message_exit_container(m);
if (r < 0)
return r;
@@ -510,9 +553,10 @@ static int vtable_append_all_properties(
r = invoke_property_get(bus, v, path, c->interface, v->x.property.member, reply, error, vtable_property_convert_userdata(v, userdata));
if (r < 0)
return r;
-
if (sd_bus_error_is_set(error))
return 0;
+ if (bus->nodes_modified)
+ return 0;
r = sd_bus_message_close_container(reply);
if (r < 0)
@@ -561,6 +605,8 @@ static int property_get_all_callbacks_run(
r = node_vtable_get_userdata(bus, m->path, c, &u);
if (r < 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
if (r == 0)
continue;
@@ -570,8 +616,6 @@ static int property_get_all_callbacks_run(
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;
@@ -583,6 +627,8 @@ static int property_get_all_callbacks_run(
return 1;
}
+ if (bus->nodes_modified)
+ return 0;
}
if (!found_interface) {
@@ -650,6 +696,8 @@ static bool bus_node_exists(
if (node_vtable_get_userdata(bus, path, c, NULL) > 0)
return true;
+ if (bus->nodes_modified)
+ return false;
}
return !require_fallback && (n->enumerators || n->object_manager);
@@ -677,6 +725,8 @@ static int process_introspect(
r = get_child_nodes(bus, m->path, n, &s);
if (r < 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
r = introspect_begin(&intro);
if (r < 0)
@@ -695,6 +745,8 @@ static int process_introspect(
r = node_vtable_get_userdata(bus, m->path, c, NULL);
if (r < 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
if (r == 0)
continue;
@@ -711,7 +763,8 @@ static int process_introspect(
r = bus_node_exists(bus, n, m->path, require_fallback);
if (r < 0)
return r;
-
+ if (bus->nodes_modified)
+ return 0;
if (r == 0)
goto finish;
}
@@ -768,6 +821,8 @@ static int object_manager_serialize_vtable(
r = vtable_append_all_properties(bus, reply, path, c, userdata, error);
if (r < 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
r = sd_bus_message_close_container(reply);
if (r < 0)
@@ -812,6 +867,8 @@ static int object_manager_serialize_path(
r = node_vtable_get_userdata(bus, path, i, &u);
if (r < 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
if (r == 0)
continue;
@@ -836,6 +893,8 @@ static int object_manager_serialize_path(
return r;
if (sd_bus_error_is_set(error))
return 0;
+ if (bus->nodes_modified)
+ return 0;
}
if (found_something) {
@@ -871,6 +930,8 @@ static int object_manager_serialize_path_and_fallbacks(
return r;
if (sd_bus_error_is_set(error))
return 0;
+ if (bus->nodes_modified)
+ return 0;
/* Second, add fallback vtables registered for any of the prefixes */
prefix = alloca(strlen(path) + 1);
@@ -878,9 +939,10 @@ 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;
}
return 0;
@@ -909,6 +971,8 @@ static int process_get_managed_objects(
r = get_child_nodes(bus, m->path, n, &s);
if (r < 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
r = sd_bus_message_new_method_return(bus, m, &reply);
if (r < 0)
@@ -960,6 +1024,9 @@ static int process_get_managed_objects(
return 1;
}
+
+ if (bus->nodes_modified)
+ return 0;
}
}
@@ -998,6 +1065,8 @@ static int object_find_and_run(
r = node_callbacks_run(bus, m, n->callbacks, require_fallback, found_object);
if (r != 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
if (!m->interface || !m->member)
return 0;
@@ -1012,6 +1081,8 @@ static int object_find_and_run(
r = method_callbacks_run(bus, m, v, require_fallback, found_object);
if (r != 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
}
/* Then, look for a known property */
@@ -1071,11 +1142,13 @@ static int object_find_and_run(
return r;
}
+ if (bus->nodes_modified)
+ return 0;
+
if (!*found_object) {
r = bus_node_exists(bus, n, m->path, require_fallback);
if (r < 0)
return r;
-
if (r > 0)
*found_object = true;
}
@@ -1256,6 +1329,8 @@ static int bus_add_object(
c->is_fallback = fallback;
LIST_PREPEND(callbacks, n->callbacks, c);
+ bus->nodes_modified = true;
+
return 0;
fail:
@@ -1293,6 +1368,7 @@ static int bus_remove_object(
free(c);
bus_node_gc(bus, n);
+ bus->nodes_modified = true;
return 1;
}
@@ -1547,6 +1623,8 @@ static int add_object_vtable_internal(
}
LIST_PREPEND(vtables, n->vtables, c);
+ bus->nodes_modified = true;
+
return 0;
fail:
@@ -1587,6 +1665,8 @@ static int remove_object_vtable_internal(
free_node_vtable(bus, c);
bus_node_gc(bus, n);
+ bus->nodes_modified = true;
+
return 1;
}
@@ -1657,6 +1737,9 @@ int sd_bus_add_node_enumerator(
c->userdata = userdata;
LIST_PREPEND(enumerators, n->enumerators, c);
+
+ bus->nodes_modified = true;
+
return 0;
fail:
@@ -1695,6 +1778,8 @@ int sd_bus_remove_node_enumerator(
bus_node_gc(bus, n);
+ bus->nodes_modified = true;
+
return 1;
}
@@ -1738,6 +1823,8 @@ static int emit_properties_changed_on_interface(
r = node_vtable_get_userdata(bus, path, c, &u);
if (r <= 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
r = sd_bus_message_new_signal(bus, path, "org.freedesktop.DBus.Properties", "PropertiesChanged", &m);
if (r < 0)
@@ -1788,9 +1875,10 @@ static int emit_properties_changed_on_interface(
r = invoke_property_get(bus, v->vtable, m->path, interface, *property, m, &error, vtable_property_convert_userdata(v->vtable, u));
if (r < 0)
return r;
-
if (sd_bus_error_is_set(&error))
return bus_error_to_errno(&error);
+ if (bus->nodes_modified)
+ return 0;
r = sd_bus_message_close_container(m);
if (r < 0)
@@ -1856,16 +1944,25 @@ int sd_bus_emit_properties_changed_strv(
if (strv_isempty(names))
return 0;
- r = emit_properties_changed_on_interface(bus, path, path, interface, false, names);
- if (r != 0)
- return r;
+ do {
+ bus->nodes_modified = false;
- prefix = alloca(strlen(path) + 1);
- OBJECT_PATH_FOREACH_PREFIX(prefix, path) {
- r = emit_properties_changed_on_interface(bus, prefix, path, interface, true, names);
+ r = emit_properties_changed_on_interface(bus, path, path, interface, false, names);
if (r != 0)
return r;
- }
+ if (bus->nodes_modified)
+ continue;
+
+ prefix = alloca(strlen(path) + 1);
+ OBJECT_PATH_FOREACH_PREFIX(prefix, path) {
+ r = emit_properties_changed_on_interface(bus, prefix, path, interface, true, names);
+ if (r != 0)
+ return r;
+ if (bus->nodes_modified)
+ break;
+ }
+
+ } while (bus->nodes_modified);
return -ENOENT;
}
@@ -1936,6 +2033,8 @@ static int interfaces_added_append_one_prefix(
r = node_vtable_get_userdata(bus, path, c, &u);
if (r <= 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
r = sd_bus_message_append_basic(m, 's', interface);
if (r < 0)
@@ -1948,9 +2047,10 @@ static int interfaces_added_append_one_prefix(
r = vtable_append_all_properties(bus, m,path, c, u, &error);
if (r < 0)
return r;
-
if (sd_bus_error_is_set(&error))
return bus_error_to_errno(&error);
+ if (bus->nodes_modified)
+ return 0;
r = sd_bus_message_close_container(m);
if (r < 0)
@@ -1976,12 +2076,16 @@ static int interfaces_added_append_one(
r = interfaces_added_append_one_prefix(bus, m, path, path, interface, false);
if (r != 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
prefix = alloca(strlen(path) + 1);
OBJECT_PATH_FOREACH_PREFIX(prefix, path) {
r = interfaces_added_append_one_prefix(bus, m, prefix, path, interface, true);
if (r != 0)
return r;
+ if (bus->nodes_modified)
+ return 0;
}
return -ENOENT;
@@ -2002,37 +2106,51 @@ int sd_bus_emit_interfaces_added_strv(sd_bus *bus, const char *path, char **inte
if (strv_isempty(interfaces))
return 0;
- r = sd_bus_message_new_signal(bus, path, "org.freedesktop.DBus.ObjectManager", "InterfacesAdded", &m);
- if (r < 0)
- return r;
-
- r = sd_bus_message_append_basic(m, 'o', path);
- if (r < 0)
- return r;
+ do {
+ bus->nodes_modified = false;
- r = sd_bus_message_open_container(m, 'a', "{sa{sv}}");
- if (r < 0)
- return r;
+ if (m)
+ m = sd_bus_message_unref(m);
- STRV_FOREACH(i, interfaces) {
- assert_return(interface_name_is_valid(*i), -EINVAL);
+ r = sd_bus_message_new_signal(bus, path, "org.freedesktop.DBus.ObjectManager", "InterfacesAdded", &m);
+ if (r < 0)
+ return r;
- r = sd_bus_message_open_container(m, 'e', "sa{sv}");
+ r = sd_bus_message_append_basic(m, 'o', path);
if (r < 0)
return r;
- r = interfaces_added_append_one(bus, m, path, *i);
+ r = sd_bus_message_open_container(m, 'a', "{sa{sv}}");
if (r < 0)
return r;
+ STRV_FOREACH(i, interfaces) {
+ assert_return(interface_name_is_valid(*i), -EINVAL);
+
+ r = sd_bus_message_open_container(m, 'e', "sa{sv}");
+ if (r < 0)
+ return r;
+
+ r = interfaces_added_append_one(bus, m, path, *i);
+ if (r < 0)
+ return r;
+
+ if (bus->nodes_modified)
+ break;
+
+ r = sd_bus_message_close_container(m);
+ if (r < 0)
+ return r;
+ }
+
+ if (bus->nodes_modified)
+ continue;
+
r = sd_bus_message_close_container(m);
if (r < 0)
return r;
- }
- r = sd_bus_message_close_container(m);
- if (r < 0)
- return r;
+ } while (bus->nodes_modified);
return sd_bus_send(bus, m, NULL);
}
@@ -2114,6 +2232,7 @@ int sd_bus_add_object_manager(sd_bus *bus, const char *path) {
return -ENOMEM;
n->object_manager = true;
+ bus->nodes_modified = true;
return 0;
}
@@ -2132,6 +2251,7 @@ int sd_bus_remove_object_manager(sd_bus *bus, const char *path) {
return 0;
n->object_manager = false;
+ bus->nodes_modified = true;
bus_node_gc(bus, n);
return 1;
diff --git a/src/libsystemd-bus/test-bus-objects.c b/src/libsystemd-bus/test-bus-objects.c
index 2757f6932a..543063f361 100644
--- a/src/libsystemd-bus/test-bus-objects.c
+++ b/src/libsystemd-bus/test-bus-objects.c
@@ -34,14 +34,6 @@
#include "bus-internal.h"
#include "bus-message.h"
-/* Test:
- *
- * Add in:
- *
- * node hierarchy updates during dispatching
- *
- */
-
struct context {
int fds[2];
bool quit;