kmscon: remove broken vt_eloop concept

We tried to avoid running unused code during shutdown by moving VT
handling into a separate eloop and run it exclusively. However, with
delayed VT switching, we need to run other event-handlers to make the VT
switch work. Therefore, run all of this during shutdown and remove the
vt_eloop event-loop.

This means that we might create new seats, displays, etc. during shutdown.
This is valid and doesn't harm kmscon, but we want to avoid doing stuff
that is undone few miliseconds later. Therefore, we set a "exiting" flag
and check that before initiating most of the big handlers.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

diff --git a/src/kmscon_main.c b/src/kmscon_main.c
index fb4233d..06186a4 100644 (file)
--- a/src/kmscon_main.c
+++ b/src/kmscon_main.c
@@ -66,9 +66,9 @@ struct app_seat {
 struct kmscon_app {
        struct conf_ctx *conf_ctx;
        struct kmscon_conf_t *conf;
+       bool exiting;
 
        struct ev_eloop *eloop;
-       struct ev_eloop *vt_eloop;
        unsigned int vt_exit_count;
 
        struct uterm_vt_master *vtm;
@@ -107,9 +107,13 @@ static int app_seat_event(struct kmscon_seat *s, unsigned int event,
                        log_debug("deactivating VT on exit, %d to go",
                                  app->vt_exit_count - 1);
                        if (!--app->vt_exit_count)
-                               ev_eloop_exit(app->vt_eloop);
+                               ev_eloop_exit(app->eloop);
                }
                break;
+       case KMSCON_SEAT_WAKE_UP:
+               if (app->exiting)
+                       return -EBUSY;
+               break;
        case KMSCON_SEAT_HUP:
                kmscon_seat_free(seat->seat);
                seat->seat = NULL;
@@ -152,6 +156,9 @@ static int app_seat_new(struct kmscon_app *app, const char *sname,
        unsigned int i, types;
        bool found;
 
+       if (app->exiting)
+               return -EBUSY;
+
        found = false;
        if (kmscon_conf_is_all_seats(app->conf)) {
                found = true;
@@ -241,7 +248,8 @@ static void app_seat_video_event(struct uterm_video *video,
 
        switch (ev->action) {
        case UTERM_NEW:
-               kmscon_seat_add_display(vid->seat->seat, ev->display);
+               if (!vid->seat->app->exiting)
+                       kmscon_seat_add_display(vid->seat->seat, ev->display);
                break;
        case UTERM_GONE:
                kmscon_seat_remove_display(vid->seat->seat, ev->display);
@@ -304,6 +312,9 @@ static int app_seat_add_video(struct app_seat *seat,
        unsigned int mode;
        struct app_video *vid;
 
+       if (seat->app->exiting)
+               return -EBUSY;
+
        if (app_seat_gpu_is_ignored(seat, type,
                                    flags & UTERM_MONITOR_DRM_BACKED,
                                    flags & UTERM_MONITOR_PRIMARY,
@@ -497,7 +508,6 @@ static void destroy_app(struct kmscon_app *app)
 {
        uterm_monitor_unref(app->mon);
        uterm_vt_master_unref(app->vtm);
-       ev_eloop_rm_eloop(app->vt_eloop);
        ev_eloop_unregister_signal_cb(app->eloop, SIGPIPE, app_sig_ignore,
                                      app);
        ev_eloop_unregister_signal_cb(app->eloop, SIGINT, app_sig_generic,
@@ -540,13 +550,7 @@ static int setup_app(struct kmscon_app *app)
                goto err_app;
        }
 
-       ret = ev_eloop_new_eloop(app->eloop, &app->vt_eloop);
-       if (ret) {
-               log_error("cannot create VT eloop object: %d", ret);
-               goto err_app;
-       }
-
-       ret = uterm_vt_master_new(&app->vtm, app->vt_eloop);
+       ret = uterm_vt_master_new(&app->vtm, app->eloop);
        if (ret) {
                log_error("cannot create VT master: %d", ret);
                goto err_app;
@@ -611,6 +615,8 @@ int main(int argc, char **argv)
                ev_eloop_run(app.eloop, -1);
        }
 
+       app.exiting = true;
+
        if (app.conf->switchvt) {
                /* The VT subsystem needs to acknowledge the VT-leave so if it
                 * returns -EINPROGRESS we need to wait for the VT-leave SIGUSR2
@@ -618,16 +624,13 @@ int main(int argc, char **argv)
                 * which is used by the VT system only. Therefore, waiting on
                 * this eloop allows us to safely wait 50ms for the SIGUSR2 to
                 * arrive.
-                * We use a timeout of 100ms to avoid haning on exit.
-                * We could also wait on app.eloop but this would allow other
-                * subsystems to continue receiving events and this is not what
-                * we want. */
+                * We use a timeout of 100ms to avoid hanging on exit. */
                log_debug("deactivating VTs during shutdown");
                ret = uterm_vt_master_deactivate_all(app.vtm);
                if (ret > 0) {
                        log_debug("waiting for %d VTs to deactivate", ret);
                        app.vt_exit_count = ret;
-                       ev_eloop_run(app.vt_eloop, 50);
+                       ev_eloop_run(app.eloop, 50);
                }
        }