[PATCH wayland 8/9] client: Replace the singleton zombie with bespoke zombies
Derek Foreman
derekf at osg.samsung.com
Fri Apr 7 20:27:54 UTC 2017
Using the singleton zombie object doesn't allow us to posthumously retain
object interface information, which makes it difficult to properly inter
future events destined for the recently deceased proxy.
Notably, this makes it impossible for zombie proxy destined file
descriptors to be properly consumed.
Instead of having a singleton zombie object, we add a new wl_map flag
(valid only on the client side where zombies roam - the existing
"legacy" flag was only ever used on the server side) to indicate that a
map entry is now a zombie.
We still have to refcount and potentially free the proxy immediately or
we're left with situations where it can be leaked forever. If we clean
up on delete_id, for example, a forced disconnect will result in a leaked
proxy (breaking much of the test suite).
So, since we must free the zombied proxy immediately, we store just the
interface for it in its previous map location, so signature information
can be retained for zombie-destined events.
Signed-off-by: Derek Foreman <derekf at osg.samsung.com>
---
src/connection.c | 20 +++++++++++++++++++-
src/wayland-client.c | 10 ++++++----
src/wayland-private.h | 12 ++++++++----
src/wayland-util.c | 22 ++++++++++++++++++++--
4 files changed, 53 insertions(+), 11 deletions(-)
diff --git a/src/connection.c b/src/connection.c
index f2ebe06..84f5d79 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -809,6 +809,24 @@ wl_connection_demarshal(struct wl_connection *connection,
return NULL;
}
+bool
+wl_object_is_zombie(struct wl_map *map, uint32_t id)
+{
+ uint32_t flags;
+
+ if (map->side == WL_MAP_SERVER_SIDE)
+ return false;
+
+ if (id >= WL_SERVER_ID_START)
+ return false;
+
+ flags = wl_map_lookup_flags(map, id);
+ if (flags & WL_MAP_ENTRY_ZOMBIE)
+ return true;
+
+ return false;
+}
+
int
wl_closure_lookup_objects(struct wl_closure *closure, struct wl_map *objects)
{
@@ -830,7 +848,7 @@ wl_closure_lookup_objects(struct wl_closure *closure, struct wl_map *objects)
closure->args[i].o = NULL;
object = wl_map_lookup(objects, id);
- if (object == WL_ZOMBIE_OBJECT) {
+ if (wl_object_is_zombie(objects, id)) {
/* references object we've already
* destroyed client side */
object = NULL;
diff --git a/src/wayland-client.c b/src/wayland-client.c
index 7243d3d..2cd713d 100644
--- a/src/wayland-client.c
+++ b/src/wayland-client.c
@@ -408,8 +408,10 @@ proxy_destroy(struct wl_proxy *proxy)
if (proxy->flags & WL_PROXY_FLAG_ID_DELETED)
wl_map_remove(&proxy->display->objects, proxy->object.id);
else if (proxy->object.id < WL_SERVER_ID_START)
- wl_map_insert_at(&proxy->display->objects, 0,
- proxy->object.id, WL_ZOMBIE_OBJECT);
+ wl_map_insert_at(&proxy->display->objects,
+ WL_MAP_ENTRY_ZOMBIE,
+ proxy->object.id,
+ (void *)proxy->object.interface);
else
wl_map_insert_at(&proxy->display->objects, 0,
proxy->object.id, NULL);
@@ -837,7 +839,7 @@ display_handle_delete_id(void *data, struct wl_display *display, uint32_t id)
if (!proxy)
wl_log("error: received delete_id for unknown id (%u)\n", id);
- if (proxy && proxy != WL_ZOMBIE_OBJECT)
+ if (proxy && !wl_object_is_zombie(&display->objects, id))
proxy->flags |= WL_PROXY_FLAG_ID_DELETED;
else
wl_map_remove(&display->objects, id);
@@ -1228,7 +1230,7 @@ queue_event(struct wl_display *display, int len)
return 0;
proxy = wl_map_lookup(&display->objects, id);
- if (!proxy || proxy == WL_ZOMBIE_OBJECT) {
+ if (!proxy || wl_object_is_zombie(&display->objects, id)) {
wl_connection_consume(display->connection, size);
return size;
}
diff --git a/src/wayland-private.h b/src/wayland-private.h
index d906a6f..2acd2d4 100644
--- a/src/wayland-private.h
+++ b/src/wayland-private.h
@@ -57,9 +57,6 @@ struct wl_object {
uint32_t id;
};
-extern struct wl_object global_zombie_object;
-#define WL_ZOMBIE_OBJECT ((void*)&global_zombie_object)
-
int
wl_interface_equal(const struct wl_interface *iface1,
const struct wl_interface *iface2);
@@ -69,7 +66,8 @@ wl_interface_equal(const struct wl_interface *iface1,
* flags. If more flags are ever added, the implementation of wl_map will have
* to change to allow for new flags */
enum wl_map_entry_flags {
- WL_MAP_ENTRY_LEGACY = (1 << 0)
+ WL_MAP_ENTRY_LEGACY = (1 << 0), /* Server side only */
+ WL_MAP_ENTRY_ZOMBIE = (1 << 0) /* Client side only */
};
struct wl_map {
@@ -107,6 +105,9 @@ uint32_t
wl_map_lookup_flags(struct wl_map *map, uint32_t i);
void
+wl_map_set_flags(struct wl_map *map, uint32_t i, uint32_t flags);
+
+void
wl_map_for_each(struct wl_map *map, wl_iterator_func_t func, void *data);
struct wl_connection *
@@ -189,6 +190,9 @@ wl_connection_demarshal(struct wl_connection *connection,
struct wl_map *objects,
const struct wl_message *message);
+bool
+wl_object_is_zombie(struct wl_map *map, uint32_t id);
+
int
wl_closure_lookup_objects(struct wl_closure *closure, struct wl_map *objects);
diff --git a/src/wayland-util.c b/src/wayland-util.c
index cab7fc5..71abb2e 100644
--- a/src/wayland-util.c
+++ b/src/wayland-util.c
@@ -153,8 +153,6 @@ wl_array_copy(struct wl_array *array, struct wl_array *source)
/** \cond */
-struct wl_object global_zombie_object;
-
int
wl_interface_equal(const struct wl_interface *a, const struct wl_interface *b)
{
@@ -360,6 +358,26 @@ wl_map_lookup_flags(struct wl_map *map, uint32_t i)
return 0;
}
+void
+wl_map_set_flags(struct wl_map *map, uint32_t i, uint32_t flags)
+{
+ union map_entry *start;
+ uint32_t count;
+ struct wl_array *entries;
+
+ if (i < WL_SERVER_ID_START) {
+ entries = &map->client_entries;
+ } else {
+ entries = &map->server_entries;
+ i -= WL_SERVER_ID_START;
+ }
+
+ start = entries->data;
+ count = entries->size / sizeof *start;
+ if (i < count && !map_entry_is_free(start[i]))
+ start[i].next |= (flags & 0x1) << 1;
+}
+
static enum wl_iterator_result
for_each_helper(struct wl_array *entries, wl_iterator_func_t func, void *data)
{
--
2.11.0
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