From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753010Ab2LXIOc (ORCPT ); Mon, 24 Dec 2012 03:14:32 -0500 Received: from mailhub.sw.ru ([195.214.232.25]:19831 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752951Ab2LXIOa (ORCPT ); Mon, 24 Dec 2012 03:14:30 -0500 From: Andrey Vagin To: linux-kernel@vger.kernel.org Cc: criu@openvz.org, linux-fsdevel@vger.kernel.org, Andrey Vagin , Serge Hallyn , Oleg Nesterov , Andrew Morton , "Eric W. Biederman" , Al Viro , Pavel Emelyanov , Cyrill Gorcunov Subject: =?UTF-8?q?=5BPATCH=200/4=5D=20signalfd=3A=20a=20kernel=20interface=20for=20dumping/restoring=20pending=20signals?= Date: Mon, 24 Dec 2012 12:13:23 +0400 Message-Id: <1356336807-5517-1-git-send-email-avagin@openvz.org> X-Mailer: git-send-email 1.7.11.7 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The idea is simple. We need to get the siginfo for each signal on dump, and then return it back on restore. The first problem is that the kernel doesn’t report complete siginfo-s in user-space. In a signal handler the kernel strips SI_CODE from siginfo. When a siginfo is received from signalfd, it has a different format with fixed sizes of fields. The interface of signalfd was extended. If a signalfd is created with the flag SFD_RAW, it returns siginfo in a raw format. We need to choose a queue, so two flags SFD_GROUP and SFD_PRIVATE were added. rt_sigqueueinfo looks suitable for restoring signals, but it can’t send siginfo with a positive si_code, because these codes are reserved for the kernel. In the real world each person has right to do anything with himself, so I think a process should able to send any siginfo to itself. Cc: Serge Hallyn Cc: Oleg Nesterov Cc: Andrew Morton Cc: "Eric W. Biederman" Cc: Al Viro Cc: Pavel Emelyanov CC: Cyrill Gorcunov -- 1.7.11.7