+static int manager_vt_switch(sd_event_source *src, const struct signalfd_siginfo *si, void *data) {
+ Manager *m = data;
+ Session *active, *iter;
+
+ /*
+ * We got a VT-switch signal and we have to acknowledge it immediately.
+ * Preferably, we'd just use m->seat0->active->vtfd, but unfortunately,
+ * old user-space might run multiple sessions on a single VT, *sigh*.
+ * Therefore, we have to iterate all sessions and find one with a vtfd
+ * on the requested VT.
+ * As only VTs with active controllers have VT_PROCESS set, our current
+ * notion of the active VT might be wrong (for instance if the switch
+ * happens while we setup VT_PROCESS). Therefore, read the current VT
+ * first and then use s->active->vtnr as reference. Note that this is
+ * not racy, as no further VT-switch can happen as long as we're in
+ * synchronous VT_PROCESS mode.
+ */
+
+ assert(m->seat0);
+ seat_read_active_vt(m->seat0);
+
+ active = m->seat0->active;
+ if (!active || active->vtnr < 1) {
+ log_warning("Received VT_PROCESS signal without a registered session on that VT.");
+ return 0;
+ }
+
+ if (active->vtfd >= 0) {
+ ioctl(active->vtfd, VT_RELDISP, 1);
+ } else {
+ LIST_FOREACH(sessions_by_seat, iter, m->seat0->sessions) {
+ if (iter->vtnr == active->vtnr && iter->vtfd >= 0) {
+ ioctl(iter->vtfd, VT_RELDISP, 1);
+ break;
+ }
+ }
+ }
+
+ return 0;
+}
+