From 44eb1adda98f6733264c0e8fbc569656c6ff2de0 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sat, 5 Sep 2015 19:43:29 +0200 Subject: sd-bus: make introspection data non-recursive Currently, our introspection data looks like this: ... ... ... (ordered alphabetically for better visibility) This is grossly incorrect. The spec says that we're allowed to return non-directed children, however, it does not allow us to return data recursively in multiple parents. If we return "org", then we must not return anything else that starts with "org/". It is unclear, whether we can include child-nodes as a tree. Moreover, it is usually not what the caller wants. Hence, this patch changes sd-bus to never return introspection data recursively. Instead, only a single child-layer is returned. This patch relies on enumerators to never return hierarchies. If someone registers an enumerator via sd_bus_add_enumerator, they better register sub-enumerators if they support *TRUE* hierarchies. Each enumerator is treated as a single layer and not filtered. Enumerators are still allowed to return nested data. However, that data is still required to be a single hierarchy. For instance, returning "/org/foo" and "/com/bar" is fine, but including "/com" or "/org" in that dataset is not. This should be the default for enumerators and I see no reason to filter in sd-bus. Moreover, filtering that data-set would require to sort the strv by path and then do prefix-filtering. This is O(n log n), which would be fine, but still better to avoid. Fixes #664. --- src/libsystemd/sd-bus/bus-objects.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) (limited to 'src/libsystemd/sd-bus/bus-objects.c') diff --git a/src/libsystemd/sd-bus/bus-objects.c b/src/libsystemd/sd-bus/bus-objects.c index 0593aa658a..1d061cb9cf 100644 --- a/src/libsystemd/sd-bus/bus-objects.c +++ b/src/libsystemd/sd-bus/bus-objects.c @@ -169,11 +169,18 @@ static int add_enumerated_to_set( return 0; } +enum { + /* if set, add_subtree() works recursively */ + CHILDREN_RECURSIVE = (1U << 1), + /* if set, add_subtree() scans object-manager hierarchies recursively */ + CHILDREN_SUBHIERARCHIES = (1U << 0), +}; + static int add_subtree_to_set( sd_bus *bus, const char *prefix, struct node *n, - bool skip_subhierarchies, + unsigned int flags, Set *s, sd_bus_error *error) { @@ -205,8 +212,9 @@ static int add_subtree_to_set( if (r < 0 && r != -EEXIST) return r; - if (!skip_subhierarchies || !i->object_managers) { - r = add_subtree_to_set(bus, prefix, i, skip_subhierarchies, s, error); + if ((flags & CHILDREN_RECURSIVE) && + ((flags & CHILDREN_SUBHIERARCHIES) || !i->object_managers)) { + r = add_subtree_to_set(bus, prefix, i, flags, s, error); if (r < 0) return r; if (bus->nodes_modified) @@ -221,7 +229,7 @@ static int get_child_nodes( sd_bus *bus, const char *prefix, struct node *n, - bool skip_subhierarchies, + unsigned int flags, Set **_s, sd_bus_error *error) { @@ -237,7 +245,7 @@ static int get_child_nodes( if (!s) return -ENOMEM; - r = add_subtree_to_set(bus, prefix, n, skip_subhierarchies, s, error); + r = add_subtree_to_set(bus, prefix, n, flags, s, error); if (r < 0) { set_free_free(s); return r; @@ -907,7 +915,7 @@ static int process_introspect( assert(n); assert(found_object); - r = get_child_nodes(bus, m->path, n, false, &s, &error); + r = get_child_nodes(bus, m->path, n, 0, &s, &error); if (r < 0) return bus_maybe_reply_error(m, r, &error); if (bus->nodes_modified) @@ -1173,7 +1181,7 @@ static int process_get_managed_objects( if (require_fallback || !n->object_managers) return 0; - r = get_child_nodes(bus, m->path, n, true, &s, &error); + r = get_child_nodes(bus, m->path, n, CHILDREN_RECURSIVE, &s, &error); if (r < 0) return r; if (bus->nodes_modified) -- cgit v1.2.3