From ba4d05f9ddf188dd08dd98b1d9a54343c6f1bf50 Mon Sep 17 00:00:00 2001
From: Campbell Jones <git@serebit.com>
Date: Fri, 12 Apr 2024 18:48:39 -0400
Subject: [PATCH] Short-circuit if missing data in event listeners

Instead of segfaulting, of course
---
 src/foreign_toplevel.cpp      | 26 +++++++++++++-
 src/input/cursor.cpp          | 66 +++++++++++++++++++++++++++++++++++
 src/input/keyboard.cpp        |  9 +++--
 src/input/seat.cpp            | 30 ++++++++++++++++
 src/output.cpp                |  6 ++++
 src/server.cpp                | 39 +++++++++++++++++++--
 src/surface/layer.cpp         | 10 ++++++
 src/surface/popup.cpp         |  9 +++++
 src/surface/xdg_view.cpp      |  6 ++++
 src/surface/xwayland_view.cpp | 11 ++++++
 src/xwayland.cpp              |  5 +++
 11 files changed, 212 insertions(+), 5 deletions(-)

diff --git a/src/foreign_toplevel.cpp b/src/foreign_toplevel.cpp
index baa2ddfb4..0dd215b27 100644
--- a/src/foreign_toplevel.cpp
+++ b/src/foreign_toplevel.cpp
@@ -1,10 +1,19 @@
 #include "foreign_toplevel.hpp"
-
 #include "output.hpp"
+
 #include "server.hpp"
 #include "surface/view.hpp"
 
+#include "wlr-wrap-start.hpp"
+#include <wlr/util/log.h>
+#include "wlr-wrap-end.hpp"
+
 static void foreign_toplevel_handle_request_maximize_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_foreign_toplevel_handle_v1.events.request_maximize");
+		return;
+	}
+
 	const ForeignToplevelHandle& handle = magpie_container_of(listener, handle, request_activate);
 	const auto& event = *static_cast<wlr_foreign_toplevel_handle_v1_maximized_event*>(data);
 
@@ -13,6 +22,11 @@ static void foreign_toplevel_handle_request_maximize_notify(wl_listener* listene
 }
 
 static void foreign_toplevel_handle_request_fullscreen_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_foreign_toplevel_handle_v1.events.request_fullscreen");
+		return;
+	}
+
 	const ForeignToplevelHandle& handle = magpie_container_of(listener, handle, request_activate);
 	const auto& event = *static_cast<wlr_foreign_toplevel_handle_v1_maximized_event*>(data);
 
@@ -21,6 +35,11 @@ static void foreign_toplevel_handle_request_fullscreen_notify(wl_listener* liste
 }
 
 static void foreign_toplevel_handle_request_minimize_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_foreign_toplevel_handle_v1.events.request_minimize");
+		return;
+	}
+
 	const ForeignToplevelHandle& handle = magpie_container_of(listener, handle, request_activate);
 	const auto& event = *static_cast<wlr_foreign_toplevel_handle_v1_minimized_event*>(data);
 
@@ -41,6 +60,11 @@ static void foreign_toplevel_handle_request_close_notify(wl_listener* listener,
 }
 
 static void foreign_toplevel_handle_set_rectangle_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_foreign_toplevel_handle_v1.events.set_rectangle");
+		return;
+	}
+
 	const ForeignToplevelHandle& handle = magpie_container_of(listener, handle, set_rectangle);
 	const auto& event = *static_cast<wlr_foreign_toplevel_handle_v1_set_rectangle_event*>(data);
 
diff --git a/src/input/cursor.cpp b/src/input/cursor.cpp
index 8b3cd0102..0e4be5233 100644
--- a/src/input/cursor.cpp
+++ b/src/input/cursor.cpp
@@ -18,6 +18,7 @@
 #include <wlr/types/wlr_seat.h>
 #include <wlr/types/wlr_xcursor_manager.h>
 #include <wlr/util/edges.h>
+#include <wlr/util/log.h>
 #include "wlr-wrap-end.hpp"
 
 void Cursor::process_resize(const uint32_t time) const {
@@ -93,6 +94,11 @@ void Cursor::process_move(const uint32_t time) {
 /* This event is forwarded by the cursor when a pointer emits an axis event,
  * for example when you move the scroll wheel. */
 static void cursor_axis_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.cursor_axis");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, axis);
 	const auto* event = static_cast<wlr_pointer_axis_event*>(data);
 
@@ -119,6 +125,11 @@ static void cursor_frame_notify(wl_listener* listener, void*) {
  * so we have to warp the mouse there. There is also some hardware which
  * emits these events. */
 static void cursor_motion_absolute_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.motion_absolute");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, motion_absolute);
 	const auto* event = static_cast<wlr_pointer_motion_absolute_event*>(data);
 
@@ -142,6 +153,11 @@ static void cursor_motion_absolute_notify(wl_listener* listener, void* data) {
 
 /* This event is forwarded by the cursor when a pointer emits a button event. */
 static void cursor_button_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.button");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, button);
 	const auto* event = static_cast<wlr_pointer_button_event*>(data);
 
@@ -170,6 +186,11 @@ static void cursor_button_notify(wl_listener* listener, void* data) {
 /* This event is forwarded by the cursor when a pointer emits a _relative_
  * pointer motion event (i.e. a delta) */
 static void cursor_motion_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.motion");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, motion);
 	const auto* event = static_cast<wlr_pointer_motion_event*>(data);
 
@@ -189,6 +210,11 @@ static void cursor_motion_notify(wl_listener* listener, void* data) {
 }
 
 static void gesture_pinch_begin_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.pinch_begin");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, gesture_pinch_begin);
 	const auto* event = static_cast<wlr_pointer_pinch_begin_event*>(data);
 
@@ -196,6 +222,11 @@ static void gesture_pinch_begin_notify(wl_listener* listener, void* data) {
 }
 
 static void gesture_pinch_update_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.pinch_update");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, gesture_pinch_update);
 	const auto* event = static_cast<wlr_pointer_pinch_update_event*>(data);
 
@@ -204,6 +235,11 @@ static void gesture_pinch_update_notify(wl_listener* listener, void* data) {
 }
 
 static void gesture_pinch_end_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.pinch_end");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, gesture_pinch_end);
 	const auto* event = static_cast<wlr_pointer_pinch_end_event*>(data);
 
@@ -211,6 +247,11 @@ static void gesture_pinch_end_notify(wl_listener* listener, void* data) {
 }
 
 static void gesture_swipe_begin_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.swipe_begin");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, gesture_swipe_begin);
 	const auto* event = static_cast<wlr_pointer_swipe_begin_event*>(data);
 
@@ -218,6 +259,11 @@ static void gesture_swipe_begin_notify(wl_listener* listener, void* data) {
 }
 
 static void gesture_swipe_update_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.swipe_update");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, gesture_swipe_update);
 	const auto* event = static_cast<wlr_pointer_swipe_update_event*>(data);
 
@@ -225,6 +271,11 @@ static void gesture_swipe_update_notify(wl_listener* listener, void* data) {
 }
 
 static void gesture_swipe_end_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.swipe_end");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, gesture_swipe_end);
 	const auto* event = static_cast<wlr_pointer_swipe_end_event*>(data);
 
@@ -232,6 +283,11 @@ static void gesture_swipe_end_notify(wl_listener* listener, void* data) {
 }
 
 static void gesture_hold_begin_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.hold_begin");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, gesture_hold_begin);
 	const auto* event = static_cast<wlr_pointer_hold_begin_event*>(data);
 
@@ -239,6 +295,11 @@ static void gesture_hold_begin_notify(wl_listener* listener, void* data) {
 }
 
 static void gesture_hold_end_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.hold_end");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, gesture_hold_end);
 	const auto* event = static_cast<wlr_pointer_hold_end_event*>(data);
 
@@ -246,6 +307,11 @@ static void gesture_hold_end_notify(wl_listener* listener, void* data) {
 }
 
 static void request_set_shape_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_cursor.events.set_shape");
+		return;
+	}
+
 	Cursor& cursor = magpie_container_of(listener, cursor, request_set_shape);
 	const auto* event = static_cast<wlr_cursor_shape_manager_v1_request_set_shape_event*>(data);
 
diff --git a/src/input/keyboard.cpp b/src/input/keyboard.cpp
index a7dc0535d..d446e882c 100644
--- a/src/input/keyboard.cpp
+++ b/src/input/keyboard.cpp
@@ -12,6 +12,7 @@
 #include <wlr/backend/session.h>
 #include <wlr/types/wlr_idle_notify_v1.h>
 #include <wlr/types/wlr_seat.h>
+#include <wlr/util/log.h>
 #include "wlr-wrap-end.hpp"
 
 /* This event is raised by the keyboard base wlr_input_device to signal
@@ -61,11 +62,15 @@ static bool handle_compositor_keybinding(const Keyboard& keyboard, const uint32_
 
 /* This event is raised when a key is pressed or released. */
 static void keyboard_handle_key(wl_listener* listener, void* data) {
-	const Keyboard& keyboard = magpie_container_of(listener, keyboard, key);
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_keyboard.events.key");
+		return;
+	}
 
+	const Keyboard& keyboard = magpie_container_of(listener, keyboard, key);
 	const auto* event = static_cast<wlr_keyboard_key_event*>(data);
-	wlr_seat* seat = keyboard.seat.wlr;
 
+	wlr_seat* seat = keyboard.seat.wlr;
 	wlr_idle_notifier_v1_notify_activity(keyboard.seat.server.idle_notifier, seat);
 
 	/* Translate libinput keycode -> xkbcommon */
diff --git a/src/input/seat.cpp b/src/input/seat.cpp
index 63737ef7c..17d575ffe 100644
--- a/src/input/seat.cpp
+++ b/src/input/seat.cpp
@@ -19,6 +19,11 @@
 #include "wlr-wrap-end.hpp"
 
 static void new_input_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_seat.events.new_input");
+		return;
+	}
+
 	Seat& seat = magpie_container_of(listener, seat, new_input);
 	auto* device = static_cast<wlr_input_device*>(data);
 
@@ -26,6 +31,11 @@ static void new_input_notify(wl_listener* listener, void* data) {
 }
 
 static void new_virtual_pointer_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_seat.events.new_virtual_pointer");
+		return;
+	}
+
 	Seat& seat = magpie_container_of(listener, seat, new_virtual_pointer);
 	const auto* event = static_cast<wlr_virtual_pointer_v1_new_pointer_event*>(data);
 
@@ -33,6 +43,11 @@ static void new_virtual_pointer_notify(wl_listener* listener, void* data) {
 }
 
 static void new_virtual_keyboard_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_seat.events.new_virtual_keyboard");
+		return;
+	}
+
 	Seat& seat = magpie_container_of(listener, seat, new_virtual_keyboard);
 	auto* keyboard = static_cast<wlr_virtual_keyboard_v1*>(data);
 
@@ -40,6 +55,11 @@ static void new_virtual_keyboard_notify(wl_listener* listener, void* data) {
 }
 
 static void new_pointer_constraint_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_seat.events.new_pointer_constraint");
+		return;
+	}
+
 	Seat& seat = magpie_container_of(listener, seat, new_pointer_constraint);
 	auto* wlr_constraint = static_cast<wlr_pointer_constraint_v1*>(data);
 
@@ -51,6 +71,11 @@ static void new_pointer_constraint_notify(wl_listener* listener, void* data) {
 }
 
 static void request_cursor_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_seat.events.request_cursor");
+		return;
+	}
+
 	const Seat& seat = magpie_container_of(listener, seat, request_cursor);
 	const auto* event = static_cast<wlr_seat_pointer_request_set_cursor_event*>(data);
 
@@ -70,6 +95,11 @@ static void request_cursor_notify(wl_listener* listener, void* data) {
  * ignore such requests if they so choose, but in magpie we always honor
  */
 static void request_set_selection_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_seat.events.request_set_selection");
+		return;
+	}
+
 	const Seat& seat = magpie_container_of(listener, seat, request_set_selection);
 	const auto* event = static_cast<wlr_seat_request_set_selection_event*>(data);
 
diff --git a/src/output.cpp b/src/output.cpp
index fbb8e4982..7fb982f3d 100644
--- a/src/output.cpp
+++ b/src/output.cpp
@@ -10,11 +10,17 @@
 #include <wlr-wrap-start.hpp>
 #include <wlr/types/wlr_layer_shell_v1.h>
 #include <wlr/types/wlr_output_layout.h>
+#include <wlr/util/log.h>
 #include <wlr-wrap-end.hpp>
 
 /* This function is called every time an output is ready to display a frame,
  * generally at the output's refresh rate (e.g. 60Hz). */
 static void output_request_state_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_output.events.request_state");
+		return;
+	}
+
 	Output& output = magpie_container_of(listener, output, request_state);
 	const auto* event = static_cast<wlr_output_event_request_state*>(data);
 
diff --git a/src/server.cpp b/src/server.cpp
index 10b5bb3c4..5011a64a2 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -120,6 +120,11 @@ Surface* Server::surface_at(const double lx, const double ly, wlr_surface** wlr,
 /* This event is raised by the backend when a new output (aka a display or
  * monitor) becomes available. */
 static void new_output_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_backend.events.new_output");
+		return;
+	}
+
 	Server& server = magpie_container_of(listener, server, backend_new_output);
 	auto* new_output = static_cast<wlr_output*>(data);
 
@@ -164,6 +169,11 @@ static void new_output_notify(wl_listener* listener, void* data) {
 }
 
 static void output_power_manager_set_mode_notify(wl_listener*, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_output_power_manager.events.set_mode");
+		return;
+	}
+
 	const auto& event = *static_cast<wlr_output_power_v1_set_mode_event*>(data);
 
 	if (event.mode == ZWLR_OUTPUT_POWER_V1_MODE_ON) {
@@ -181,6 +191,11 @@ static void output_power_manager_set_mode_notify(wl_listener*, void* data) {
 /* This event is raised when wlr_xdg_shell receives a new xdg surface from a
  * client, either a toplevel (application window) or popup. */
 static void new_xdg_surface_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_xdg_shell.events.new_surface");
+		return;
+	}
+
 	Server& server = magpie_container_of(listener, server, xdg_shell_new_xdg_surface);
 	const auto& xdg_surface = *static_cast<wlr_xdg_surface*>(data);
 
@@ -193,6 +208,11 @@ static void new_xdg_surface_notify(wl_listener* listener, void* data) {
 }
 
 static void new_layer_surface_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_layer_shell_v1.events.new_surface");
+		return;
+	}
+
 	Server& server = magpie_container_of(listener, server, layer_shell_new_layer_surface);
 	auto& layer_surface = *static_cast<wlr_layer_surface_v1*>(data);
 
@@ -209,6 +229,11 @@ static void new_layer_surface_notify(wl_listener* listener, void* data) {
 }
 
 static void request_activation_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_xdg_activation_v1.events.request_activation");
+		return;
+	}
+
 	Server& server = magpie_container_of(listener, server, activation_request_activation);
 	const auto* event = static_cast<wlr_xdg_activation_v1_request_activate_event*>(data);
 
@@ -223,7 +248,12 @@ static void request_activation_notify(wl_listener* listener, void* data) {
 	}
 }
 
-static void drm_lease_notify(wl_listener* listener, void* data) {
+static void drm_lease_request_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_drm_lease_manager_v1.events.drm_lease_request");
+		return;
+	}
+
 	Server& server = magpie_container_of(listener, server, drm_lease_request);
 	auto* request = static_cast<wlr_drm_lease_request_v1*>(data);
 
@@ -269,6 +299,11 @@ void output_layout_change_notify(wl_listener* listener, void*) {
 }
 
 void output_manager_apply_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_output_manager_v1.events.apply");
+		return;
+	}
+
 	Server& server = magpie_container_of(listener, server, output_manager_apply);
 	auto& config = *static_cast<wlr_output_configuration_v1*>(data);
 
@@ -446,7 +481,7 @@ Server::Server() : listeners(*this) {
 
 	drm_manager = wlr_drm_lease_v1_manager_create(display, backend);
 	if (drm_manager != nullptr) {
-		listeners.drm_lease_request.notify = drm_lease_notify;
+		listeners.drm_lease_request.notify = drm_lease_request_notify;
 		wl_signal_add(&drm_manager->events.request, &listeners.drm_lease_request);
 	}
 
diff --git a/src/surface/layer.cpp b/src/surface/layer.cpp
index d93b666eb..b8c65c283 100644
--- a/src/surface/layer.cpp
+++ b/src/surface/layer.cpp
@@ -95,6 +95,11 @@ static void wlr_layer_surface_v1_commit_notify(wl_listener* listener, void*) {
 }
 
 static void wlr_layer_surface_v1_new_popup_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_layer_surface_v1.events.new_popup");
+		return;
+	}
+
 	Layer& layer = magpie_container_of(listener, layer, new_popup);
 	const auto* surface = static_cast<Surface*>(layer.layer_surface.surface->data);
 
@@ -102,6 +107,11 @@ static void wlr_layer_surface_v1_new_popup_notify(wl_listener* listener, void* d
 }
 
 static void wlr_layer_surface_v1_new_subsurface_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_layer_surface_v1.events.new_subsurface");
+		return;
+	}
+
 	Layer& layer = magpie_container_of(listener, layer, new_subsurface);
 	auto& subsurface = *static_cast<wlr_subsurface*>(data);
 
diff --git a/src/surface/popup.cpp b/src/surface/popup.cpp
index fce26eaca..289e76ee8 100644
--- a/src/surface/popup.cpp
+++ b/src/surface/popup.cpp
@@ -7,6 +7,10 @@
 
 #include <utility>
 
+#include "wlr-wrap-start.hpp"
+#include <wlr/util/log.h>
+#include "wlr-wrap-end.hpp"
+
 static void popup_map_notify(wl_listener* listener, void*) {
 	Popup& popup = magpie_container_of(listener, popup, map);
 
@@ -31,6 +35,11 @@ static void popup_destroy_notify(wl_listener* listener, void*) {
 }
 
 static void popup_new_popup_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_layer_surface_v1.events.new_popup");
+		return;
+	}
+
 	const Popup& popup = magpie_container_of(listener, popup, new_popup);
 
 	new Popup(popup, *static_cast<wlr_xdg_popup*>(data));
diff --git a/src/surface/xdg_view.cpp b/src/surface/xdg_view.cpp
index 37986fff9..47058d9dd 100644
--- a/src/surface/xdg_view.cpp
+++ b/src/surface/xdg_view.cpp
@@ -9,6 +9,7 @@
 
 #include "wlr-wrap-start.hpp"
 #include <wlr/types/wlr_cursor.h>
+#include <wlr/util/log.h>
 #include "wlr-wrap-end.hpp"
 
 /* Called when the surface is mapped, or ready to display on-screen. */
@@ -51,6 +52,11 @@ static void xdg_toplevel_request_move_notify(wl_listener* listener, void*) {
  * provided serial against a list of button press serials sent to this
  * client, to prevent the client from requesting this whenever they want. */
 static void xdg_toplevel_request_resize_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_xdg_toplevel.events.request_resize");
+		return;
+	}
+
 	XdgView& view = magpie_container_of(listener, view, request_resize);
 	const auto* event = static_cast<wlr_xdg_toplevel_resize_event*>(data);
 
diff --git a/src/surface/xwayland_view.cpp b/src/surface/xwayland_view.cpp
index 992a394a5..72e410b2d 100644
--- a/src/surface/xwayland_view.cpp
+++ b/src/surface/xwayland_view.cpp
@@ -12,6 +12,7 @@
 
 #include "wlr-wrap-start.hpp"
 #include <wlr/types/wlr_seat.h>
+#include <wlr/util/log.h>
 #include "wlr-wrap-end.hpp"
 
 /* Called when the surface is mapped, or ready to display on-screen. */
@@ -53,6 +54,11 @@ static void xwayland_surface_destroy_notify(wl_listener* listener, void*) {
 }
 
 static void xwayland_surface_request_configure_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_xwayland_surface.events.request_configure");
+		return;
+	}
+
 	XWaylandView& view = magpie_container_of(listener, view, request_configure);
 	const auto& event = *static_cast<wlr_xwayland_surface_configure_event*>(data);
 
@@ -89,6 +95,11 @@ static void xwayland_surface_request_move_notify(wl_listener* listener, void*) {
  * provided serial against a list of button press serials sent to this
  * client, to prevent the client from requesting this whenever they want. */
 static void xwayland_surface_request_resize_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_xwayland_surface.events.request_resize");
+		return;
+	}
+
 	XWaylandView& view = magpie_container_of(listener, view, request_resize);
 	const auto* event = static_cast<wlr_xwayland_resize_event*>(data);
 
diff --git a/src/xwayland.cpp b/src/xwayland.cpp
index 24d100fb1..e26bb5e87 100644
--- a/src/xwayland.cpp
+++ b/src/xwayland.cpp
@@ -57,6 +57,11 @@ static void ready_notify(wl_listener* listener, void*) {
 }
 
 static void new_surface_notify(wl_listener* listener, void* data) {
+	if (data == nullptr) {
+		wlr_log(WLR_ERROR, "No data passed to wlr_xwayland.events.new_surface");
+		return;
+	}
+
 	XWayland& xwayland = magpie_container_of(listener, xwayland, new_surface);
 	auto& xwayland_surface = *static_cast<wlr_xwayland_surface*>(data);