From patchwork Thu Aug 6 23:05:47 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 30891 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@bilbo.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from ozlabs.org (ozlabs.org [203.10.76.45]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.ozlabs.org", Issuer "CA Cert Signing Authority" (verified OK)) by bilbo.ozlabs.org (Postfix) with ESMTPS id 6D8A1B6F20 for ; Fri, 7 Aug 2009 09:07:36 +1000 (EST) Received: by ozlabs.org (Postfix) id 6278CDDDB6; Fri, 7 Aug 2009 09:07:36 +1000 (EST) Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id B3F01DDDA2 for ; Fri, 7 Aug 2009 09:07:35 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756870AbZHFXGr (ORCPT ); Thu, 6 Aug 2009 19:06:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756869AbZHFXGr (ORCPT ); Thu, 6 Aug 2009 19:06:47 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:59456 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756867AbZHFXGq (ORCPT ); Thu, 6 Aug 2009 19:06:46 -0400 Received: from imap1.linux-foundation.org (imap1.linux-foundation.org [140.211.169.55]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id n76N5mY9016712 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 6 Aug 2009 16:05:49 -0700 Received: from localhost.localdomain (localhost [127.0.0.1]) by imap1.linux-foundation.org (8.13.5.20060308/8.13.5/Debian-3ubuntu1.1) with ESMTP id n76N5lZj005259; Thu, 6 Aug 2009 16:05:47 -0700 Message-Id: <200908062305.n76N5lZj005259@imap1.linux-foundation.org> Subject: [patch 1/1] proc connector: add event for process becoming session leader To: davem@davemloft.net Cc: netdev@vger.kernel.org, akpm@linux-foundation.org, scott@ubuntu.com, johnpol@2ka.mipt.ru, matthltc@us.ibm.com, oleg@tv-sign.ru From: akpm@linux-foundation.org Date: Thu, 06 Aug 2009 16:05:47 -0700 X-Spam-Status: No, hits=-3.511 required=5 tests=AWL, BAYES_00, OSDL_HEADER_SUBJECT_BRACKETED X-Spam-Checker-Version: SpamAssassin 3.2.4-osdl_revision__1.47__ X-MIMEDefang-Filter: lf$Revision: 1.188 $ X-Scanned-By: MIMEDefang 2.63 on 140.211.169.13 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Scott James Remnant The act of a process becoming a session leader is a useful signal to a supervising init daemon such as Upstart. While a daemon will normally do this as part of the process of becoming a daemon, it is rare for its children to do so. When the children do, it is nearly always a sign that the child should be considered detached from the parent and not supervised along with it. The poster-child example is OpenSSH; the per-login children call setsid() so that they may control the pty connected to them. If the primary daemon dies or is restarted, we do not want to consider the per-login children and want to respawn the primary daemon without killing the children. This patch adds a new PROC_SID_EVENT and associated structure to the proc_event event_data union, it arranges for this to be emitted when the special PIDTYPE_SID pid is set. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Scott James Remnant Acked-by: Matt Helsley Cc: Oleg Nesterov Cc: Evgeniy Polyakov Cc: "David S. Miller" Signed-off-by: Andrew Morton Acked-by: David S. Miller --- drivers/connector/cn_proc.c | 25 +++++++++++++++++++++++++ include/linux/cn_proc.h | 10 ++++++++++ kernel/exit.c | 4 +++- 3 files changed, 38 insertions(+), 1 deletion(-) diff -puN drivers/connector/cn_proc.c~proc-connector-add-event-for-process-becoming-session-leader drivers/connector/cn_proc.c --- a/drivers/connector/cn_proc.c~proc-connector-add-event-for-process-becoming-session-leader +++ a/drivers/connector/cn_proc.c @@ -139,6 +139,31 @@ void proc_id_connector(struct task_struc cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL); } +void proc_sid_connector(struct task_struct *task) +{ + struct cn_msg *msg; + struct proc_event *ev; + struct timespec ts; + __u8 buffer[CN_PROC_MSG_SIZE]; + + if (atomic_read(&proc_event_num_listeners) < 1) + return; + + msg = (struct cn_msg *)buffer; + ev = (struct proc_event *)msg->data; + get_seq(&msg->seq, &ev->cpu); + ktime_get_ts(&ts); /* get high res monotonic timestamp */ + put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns); + ev->what = PROC_EVENT_SID; + ev->event_data.sid.process_pid = task->pid; + ev->event_data.sid.process_tgid = task->tgid; + + memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id)); + msg->ack = 0; /* not used */ + msg->len = sizeof(*ev); + cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL); +} + void proc_exit_connector(struct task_struct *task) { struct cn_msg *msg; diff -puN include/linux/cn_proc.h~proc-connector-add-event-for-process-becoming-session-leader include/linux/cn_proc.h --- a/include/linux/cn_proc.h~proc-connector-add-event-for-process-becoming-session-leader +++ a/include/linux/cn_proc.h @@ -52,6 +52,7 @@ struct proc_event { PROC_EVENT_EXEC = 0x00000002, PROC_EVENT_UID = 0x00000004, PROC_EVENT_GID = 0x00000040, + PROC_EVENT_SID = 0x00000080, /* "next" should be 0x00000400 */ /* "last" is the last process event: exit */ PROC_EVENT_EXIT = 0x80000000 @@ -89,6 +90,11 @@ struct proc_event { } e; } id; + struct sid_proc_event { + __kernel_pid_t process_pid; + __kernel_pid_t process_tgid; + } sid; + struct exit_proc_event { __kernel_pid_t process_pid; __kernel_pid_t process_tgid; @@ -102,6 +108,7 @@ struct proc_event { void proc_fork_connector(struct task_struct *task); void proc_exec_connector(struct task_struct *task); void proc_id_connector(struct task_struct *task, int which_id); +void proc_sid_connector(struct task_struct *task); void proc_exit_connector(struct task_struct *task); #else static inline void proc_fork_connector(struct task_struct *task) @@ -114,6 +121,9 @@ static inline void proc_id_connector(str int which_id) {} +static inline void proc_sid_connector(struct task_struct *task) +{} + static inline void proc_exit_connector(struct task_struct *task) {} #endif /* CONFIG_PROC_EVENTS */ diff -puN kernel/exit.c~proc-connector-add-event-for-process-becoming-session-leader kernel/exit.c --- a/kernel/exit.c~proc-connector-add-event-for-process-becoming-session-leader +++ a/kernel/exit.c @@ -359,8 +359,10 @@ void __set_special_pids(struct pid *pid) { struct task_struct *curr = current->group_leader; - if (task_session(curr) != pid) + if (task_session(curr) != pid) { change_pid(curr, PIDTYPE_SID, pid); + proc_sid_connector(curr); + } if (task_pgrp(curr) != pid) change_pid(curr, PIDTYPE_PGID, pid);