src/debug.c: reset last_view

Before this patch following would cause a use-after-free:
- calling the Debug action when there was at least one view around
- closing that view
- calling the Debug action again

Also add a label for the layer popup tree.

diff --git a/src/debug.c b/src/debug.c
index 83754a3d913c3c974fcc9bd542ab68b01a4b7ca4..2af52ca3c4104b2ace8545019e297942d2900094 100644 (file)
--- a/src/debug.c
+++ b/src/debug.c
@@ -14,6 +14,8 @@
 #define IGNORE_MENU true
 #define LEFT_COL_SPACE 35
 
+static struct view *last_view;
+
 static const char *
 get_node_type(struct wlr_scene_node *node)
 {
@@ -67,8 +69,7 @@ get_view_part(struct view *view, struct wlr_scene_node *node)
 }
 
 static const char *
-get_special(struct server *server, struct wlr_scene_node *node,
-       struct view **last_view)
+get_special(struct server *server, struct wlr_scene_node *node)
 {
        if (node == &server->scene->tree.node) {
                return "server->scene";
@@ -92,6 +93,9 @@ get_special(struct server *server, struct wlr_scene_node *node,
                        if (node == &output->osd_tree->node) {
                                return "output->osd_tree";
                        }
+                       if (node == &output->layer_popup_tree->node) {
+                               return "output->popup_tree";
+                       }
                        for (int i = 0; i < 4; i++) {
                                if (node == &output->layer_tree[i]->node) {
                                        return get_layer_name(i);
@@ -107,12 +111,12 @@ get_special(struct server *server, struct wlr_scene_node *node,
        struct wlr_scene_tree *grand_parent =
                node->parent ? node->parent->node.parent : NULL;
        if (grand_parent == server->view_tree) {
-               *last_view = node_view_from_node(node);
+               last_view = node_view_from_node(node);
        }
        if (node->parent == server->view_tree_always_on_top) {
-               *last_view = node_view_from_node(node);
+               last_view = node_view_from_node(node);
        }
-       const char *view_part = get_view_part(*last_view, node);
+       const char *view_part = get_view_part(last_view, node);
        if (view_part) {
                return view_part;
        }
@@ -138,8 +142,7 @@ static void
 dump_tree(struct server *server, struct wlr_scene_node *node,
        int pos, int x, int y)
 {
-       static struct view *view;
-       const char *type = get_special(server, node, &view);
+       const char *type = get_special(server, node);
 
        if (pos) {
                printf("%*c+-- ", pos, ' ');
@@ -158,8 +161,8 @@ dump_tree(struct server *server, struct wlr_scene_node *node,
        printf("%s %*c %4d  %4d  [%p]\n", type, padding, ' ', x, y, node);
 
        if ((IGNORE_MENU && node == &server->menu_tree->node)
-                       || (IGNORE_SSD && view
-                       && ssd_debug_is_root_node(view->ssd, node))) {
+                       || (IGNORE_SSD && last_view
+                       && ssd_debug_is_root_node(last_view->ssd, node))) {
                printf("%*c%s\n", pos + 4 + INDENT_SIZE, ' ', "<skipping children>");
                return;
        }
@@ -180,4 +183,10 @@ debug_dump_scene(struct server *server)
        printf("\n");
        dump_tree(server, &server->scene->tree.node, 0, 0, 0);
        printf("\n");
+
+       /*
+        * Reset last_view so we don't access a
+        * potentially free'd pointer on the next call
+        */
+       last_view = NULL;
 }