From 29726e6816e47adb199f2c84fbb4365e98bbeb6c Mon Sep 17 00:00:00 2001 From: Simon Ser Date: Mon, 3 Feb 2020 16:39:27 +0100 Subject: [PATCH] util: add wlr_output_destroy_safe This adds a generic helper to destory transient globals. See [1]. This patch depends on [2] and [3]. [1]: https://gitlab.freedesktop.org/wayland/wayland/issues/10 [2]: https://gitlab.freedesktop.org/wayland/wayland/merge_requests/28 [3]: https://gitlab.freedesktop.org/wayland/wayland/merge_requests/30 --- include/util/global.h | 15 +++++++++++++++ util/global.c | 43 +++++++++++++++++++++++++++++++++++++++++++ util/meson.build | 1 + wlroots.syms | 1 + 4 files changed, 60 insertions(+) create mode 100644 include/util/global.h create mode 100644 util/global.c diff --git a/include/util/global.h b/include/util/global.h new file mode 100644 index 00000000..ea0fda83 --- /dev/null +++ b/include/util/global.h @@ -0,0 +1,15 @@ +#ifndef UTIL_GLOBAL_H +#define UTIL_GLOBAL_H + +#include + +/** + * Destroy a transient global. + * + * Globals that are created and destroyed on the fly need special handling to + * prevent race conditions with wl_registry. Use this function to destroy them. + */ +void wlr_global_destroy_safe(struct wl_global *global, + struct wl_display *display); + +#endif diff --git a/util/global.c b/util/global.c new file mode 100644 index 00000000..a0d84ed3 --- /dev/null +++ b/util/global.c @@ -0,0 +1,43 @@ +#include +#include "util/global.h" + +struct destroy_global_data { + struct wl_global *global; + struct wl_event_source *event_source; +}; + +static int destroy_global(void *_data) { + struct destroy_global_data *data = _data; + wl_global_destroy(data->global); + wl_event_source_remove(data->event_source); + free(data); + return 0; +} + +void wlr_global_destroy_safe(struct wl_global *global, + struct wl_display *display) { + // Don't destroy the global immediately. If the global has been created + // recently, clients might try to bind to it after we've destroyed it. + // Instead, remove the global so that clients stop seeing it and wait an + // arbitrary amount of time before destroying the global as a workaround. + // See: https://gitlab.freedesktop.org/wayland/wayland/issues/10 + + wl_global_remove(global); + wl_global_set_user_data(global, NULL); // safety net + + struct wl_event_loop *event_loop = wl_display_get_event_loop(display); + struct destroy_global_data *data = calloc(1, sizeof(*data)); + if (data == NULL) { + wl_global_destroy(global); + return; + } + data->global = global; + data->event_source = + wl_event_loop_add_timer(event_loop, destroy_global, data); + if (data->event_source == NULL) { + free(data); + wl_global_destroy(global); + return; + } + wl_event_source_timer_update(data->event_source, 5000); +} diff --git a/util/meson.build b/util/meson.build index c6614275..8bdd7a74 100644 --- a/util/meson.build +++ b/util/meson.build @@ -1,5 +1,6 @@ wlr_files += files( 'array.c', + 'global.c', 'log.c', 'region.c', 'shm.c', diff --git a/wlroots.syms b/wlroots.syms index 3176f874..167046ed 100644 --- a/wlroots.syms +++ b/wlroots.syms @@ -6,5 +6,6 @@ _wlr_strip_path; local: wlr_signal_emit_safe; + wlr_global_destroy_safe; *; };