Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756318AbZFPJQ6 (ORCPT ); Tue, 16 Jun 2009 05:16:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754950AbZFPJQt (ORCPT ); Tue, 16 Jun 2009 05:16:49 -0400 Received: from zelda.netsplit.com ([87.194.19.211]:42706 "EHLO zelda.netsplit.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754210AbZFPJQs (ORCPT ); Tue, 16 Jun 2009 05:16:48 -0400 From: Scott James Remnant Date: Mon, 15 Jun 2009 13:03:08 +0100 Subject: [PATCH] proc connector: add event for process becoming session leader To: linux-kernel@vger.kernel.org Message-Id: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4304 Lines: 126 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. Signed-off-by: Scott James Remnant --- drivers/connector/cn_proc.c | 25 +++++++++++++++++++++++++ include/linux/cn_proc.h | 10 ++++++++++ kernel/exit.c | 4 +++- 3 files changed, 38 insertions(+), 1 deletions(-) diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c index c5afc98..7d48cd9 100644 --- a/drivers/connector/cn_proc.c +++ b/drivers/connector/cn_proc.c @@ -139,6 +139,31 @@ void proc_id_connector(struct task_struct *task, int which_id) 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 --git a/include/linux/cn_proc.h b/include/linux/cn_proc.h index b8125b2..47dac5e 100644 --- a/include/linux/cn_proc.h +++ b/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(struct task_struct *task, 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 --git a/kernel/exit.c b/kernel/exit.c index b6c90b5..5162589 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -360,8 +360,10 @@ 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); -- 1.6.0.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/