Fixes#3230. The static `bus` global was only ever checked for
non-NULL, not for whether the underlying connection was still alive.
If ibus disconnected (daemon restart, stale socket) or the initial
connect attempt failed, `bus` was left set to a dead/freed connection,
so every later call to xrdp_input_unicode_init() took the "already
initialized" fast path and operated on it.
- Null out bus/g_engine in the "disconnected" signal handler instead
of leaving them dangling after g_object_unref().
- Check ibus_bus_is_connected() before trusting a cached bus, and
tear down + reconnect if it's stale.
- Unref and clear bus on a failed connect attempt instead of leaving
it set.
- Guard the unrefs in xrdp_input_unicode_destroy() now that bus/
g_engine can legitimately already be NULL.
Liyi Meng
38c8db8293