chardev: report the handshake error

This can help to debug connection issues.

Related to:
https://bugzilla.redhat.com/show_bug.cgi?id=2196182

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20230510072531.3937189-1-marcandre.lureau@redhat.com>

chardev/char-socket.c

@@ -742,8 +742,12 @@ static void tcp_chr_websock_handshake(QIOTask *task, gpointer user_data)
 {
     Chardev *chr = user_data;
     SocketChardev *s = user_data;
+    Error *err = NULL;
 
-    if (qio_task_propagate_error(task, NULL)) {
+    if (qio_task_propagate_error(task, &err)) {
+        error_reportf_err(err,
+                          "websock handshake of character device %s failed: ",
+                          chr->label);
         tcp_chr_disconnect(chr);
     } else {
         if (s->do_telnetopt) {
@@ -778,8 +782,12 @@ static void tcp_chr_tls_handshake(QIOTask *task,
 {
     Chardev *chr = user_data;
     SocketChardev *s = user_data;
+    Error *err = NULL;
 
-    if (qio_task_propagate_error(task, NULL)) {
+    if (qio_task_propagate_error(task, &err)) {
+        error_reportf_err(err,
+                          "TLS handshake of character device %s failed: ",
+                          chr->label);
         tcp_chr_disconnect(chr);
     } else {
         if (s->is_websock) {