chardev: tcp: postpone TLS work until machine done

TLS handshake may create background GSource tasks, while we won't know
the correct GMainContext until the whole chardev (including frontend)
inited.  Let's postpone the initial TLS handshake until machine done.

For dynamically created tcp chardev, we don't postpone that by checking
the init_machine_done variable.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
[peterx: add missing include line, do unit test]
Signed-off-by: NPeter Xu <peterx@redhat.com>
Message-Id: <20180308140714.28906-1-peterx@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

chardev/char-socket.c

@@ -32,6 +32,7 @@
 #include "qapi/error.h"
 #include "qapi/clone-visitor.h"
 #include "qapi/qapi-visit-sockets.h"
+#include "sysemu/sysemu.h"
 
 #include "chardev/char-io.h"
 
@@ -722,6 +723,11 @@ static void tcp_chr_tls_init(Chardev *chr)
     Error *err = NULL;
     gchar *name;
 
+    if (!machine_init_done) {
+        /* This will be postponed to machine_done notifier */
+        return;
+    }
+
     if (s->is_listen) {
         tioc = qio_channel_tls_new_server(
             s->ioc, s->tls_creds,
@@ -1162,6 +1168,10 @@ static int tcp_chr_machine_done_hook(Chardev *chr)
         tcp_chr_connect_async(chr);
     }
 
+    if (s->ioc && s->tls_creds) {
+        tcp_chr_tls_init(chr);
+    }
+
     return 0;
 }