--- a/prosodyctl	Wed Oct 24 17:04:17 2018 +0200
+++ b/prosodyctl	Wed Oct 24 17:13:49 2018 +0200
@@ -867,7 +867,10 @@
 	end
 	assert(input:close());
 	assert(output:close());
-	if owner and group then
+	if not prosody.installed then
+		-- FIXME this is possibly specific to GNU chown
+		os.execute(("chown -c --reference=%s %s"):format(sh_esc(cert_basedir), sh_esc(to)));
+	elseif owner and group then
 		local ok = os.execute(("chown %s:%s %s"):format(sh_esc(owner), sh_esc(group), sh_esc(to)));
 		assert(ok == true or ok == 0, "Failed to change ownership of "..to);
 	end