Merge pull request #2003 from emersion/fix-swaylock-hotplugging

Fix swaylock crashing when plugging/unplugging output

include/swaylock/swaylock.h

@@ -50,6 +50,7 @@ struct swaylock_surface {
 	cairo_surface_t *image;
 	struct swaylock_state *state;
 	struct wl_output *output;
+	uint32_t output_global_name;
 	struct zxdg_output_v1 *xdg_output;
 	struct wl_surface *surface;
 	struct zwlr_layer_surface_v1 *layer_surface;

swaylock/main.c

@@ -64,6 +64,52 @@ static void daemonize() {
 	}
 }
 
+static void destroy_surface(struct swaylock_surface *surface) {
+	wl_list_remove(&surface->link);
+	if (surface->layer_surface != NULL) {
+		zwlr_layer_surface_v1_destroy(surface->layer_surface);
+	}
+	if (surface->surface != NULL) {
+		wl_surface_destroy(surface->surface);
+	}
+	destroy_buffer(&surface->buffers[0]);
+	destroy_buffer(&surface->buffers[1]);
+	wl_output_destroy(surface->output);
+	free(surface);
+}
+
+static const struct zwlr_layer_surface_v1_listener layer_surface_listener;
+
+static cairo_surface_t *select_image(struct swaylock_state *state,
+		struct swaylock_surface *surface);
+
+static void create_layer_surface(struct swaylock_surface *surface) {
+	struct swaylock_state *state = surface->state;
+
+	surface->image = select_image(state, surface);
+
+	surface->surface = wl_compositor_create_surface(state->compositor);
+	assert(surface->surface);
+
+	surface->layer_surface = zwlr_layer_shell_v1_get_layer_surface(
+			state->layer_shell, surface->surface, surface->output,
+			ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY, "lockscreen");
+	assert(surface->layer_surface);
+
+	zwlr_layer_surface_v1_set_size(surface->layer_surface, 0, 0);
+	zwlr_layer_surface_v1_set_anchor(surface->layer_surface,
+			ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP |
+			ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT |
+			ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM |
+			ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT);
+	zwlr_layer_surface_v1_set_exclusive_zone(surface->layer_surface, -1);
+	zwlr_layer_surface_v1_set_keyboard_interactivity(
+			surface->layer_surface, true);
+	zwlr_layer_surface_v1_add_listener(surface->layer_surface,
+			&layer_surface_listener, surface);
+	wl_surface_commit(surface->surface);
+}
+
 static void layer_surface_configure(void *data,
 		struct zwlr_layer_surface_v1 *layer_surface,
 		uint32_t serial, uint32_t width, uint32_t height) {
@@ -77,9 +123,7 @@ static void layer_surface_configure(void *data,
 static void layer_surface_closed(void *data,
 		struct zwlr_layer_surface_v1 *layer_surface) {
 	struct swaylock_surface *surface = data;
-	zwlr_layer_surface_v1_destroy(surface->layer_surface);
+	destroy_surface(surface);
-	wl_surface_destroy(surface->surface);
-	surface->state->run_display = false;
 }
 
 static const struct zwlr_layer_surface_v1_listener layer_surface_listener = {
@@ -181,14 +225,27 @@ static void handle_global(void *data, struct wl_registry *registry,
 		surface->state = state;
 		surface->output = wl_registry_bind(registry, name,
 				&wl_output_interface, 3);
+		surface->output_global_name = name;
 		wl_output_add_listener(surface->output, &_wl_output_listener, surface);
 		wl_list_insert(&state->surfaces, &surface->link);
+
+		if (state->run_display) {
+			create_layer_surface(surface);
+			wl_display_roundtrip(state->display);
+		}
 	}
 }
 
 static void handle_global_remove(void *data, struct wl_registry *registry,
 		uint32_t name) {
-	// who cares
+	struct swaylock_state *state = data;
+	struct swaylock_surface *surface;
+	wl_list_for_each(surface, &state->surfaces, link) {
+		if (surface->output_global_name == name) {
+			destroy_surface(surface);
+			break;
+		}
+	}
 }
 
 static const struct wl_registry_listener registry_listener = {
@@ -276,7 +333,7 @@ int main(int argc, char **argv) {
 		{0, 0, 0, 0}
 	};
 
-	const char *usage =
+	const char usage[] =
 		"Usage: swaylock [options...]\n"
 		"\n"
 		"  -h, --help                     Show help message and quit.\n"
@@ -288,13 +345,13 @@ int main(int argc, char **argv) {
 		"  -u, --no-unlock-indicator      Disable the unlock indicator.\n"
 		"  -f, --daemonize                Detach from the controlling terminal.\n";
 
-	struct swaylock_args args = {
+	state.args = (struct swaylock_args){
 		.mode = BACKGROUND_MODE_SOLID_COLOR,
 		.color = 0xFFFFFFFF,
 		.show_indicator = true,
 	};
-	state.args = args;
 	wl_list_init(&state.images);
+
 	wlr_log_init(L_DEBUG, NULL);
 
 	int c;
@@ -369,6 +426,8 @@ int main(int argc, char **argv) {
 		return 0;
 	}
 
+	zwlr_input_inhibit_manager_v1_get_inhibitor(state.input_inhibit_manager);
+
 	if (state.zxdg_output_manager) {
 		struct swaylock_surface *surface;
 		wl_list_for_each(surface, &state.surfaces, link) {
@@ -385,33 +444,9 @@ int main(int argc, char **argv) {
 
 	struct swaylock_surface *surface;
 	wl_list_for_each(surface, &state.surfaces, link) {
-		surface->image = select_image(&state, surface);
+		create_layer_surface(surface);
-
-		surface->surface = wl_compositor_create_surface(state.compositor);
-		assert(surface->surface);
-
-		surface->layer_surface = zwlr_layer_shell_v1_get_layer_surface(
-				state.layer_shell, surface->surface, surface->output,
-				ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY, "lockscreen");
-		assert(surface->layer_surface);
-
-		zwlr_layer_surface_v1_set_size(surface->layer_surface, 0, 0);
-		zwlr_layer_surface_v1_set_anchor(surface->layer_surface,
-				ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP |
-				ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT |
-				ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM |
-				ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT);
-		zwlr_layer_surface_v1_set_exclusive_zone(surface->layer_surface, -1);
-		zwlr_layer_surface_v1_set_keyboard_interactivity(
-				surface->layer_surface, true);
-		zwlr_layer_surface_v1_add_listener(surface->layer_surface,
-				&layer_surface_listener, surface);
-		wl_surface_commit(surface->surface);
-		wl_display_roundtrip(state.display);
 	}
 
-	zwlr_input_inhibit_manager_v1_get_inhibitor(state.input_inhibit_manager);
-
 	state.run_display = true;
 	while (wl_display_dispatch(state.display) != -1 && state.run_display) {
 		// This space intentionally left blank

swaylock/render.c

@@ -17,6 +17,9 @@ void render_frame(struct swaylock_surface *surface) {
 
 	int buffer_width = surface->width * surface->scale;
 	int buffer_height = surface->height * surface->scale;
+	if (buffer_width == 0 || buffer_height == 0) {
+		return; // not yet configured
+	}
 
 	surface->current_buffer = get_next_buffer(state->shm,
 			surface->buffers, buffer_width, buffer_height);