- r = sd_bus_call_method(
- m->bus,
- "org.freedesktop.systemd1",
- "/org/freedesktop/systemd1",
- "org.freedesktop.systemd1.Manager",
- "Subscribe",
- &error,
- NULL, NULL);
- if (r < 0) {
- log_error("Failed to enable subscription: %s", bus_error_message(&error, r));
- return r;
- }
+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.
+ */