connector: add parent pid and tgid to coredump and exit events

The intention is to get notified of process failures as soon
as possible, before a possible core dumping (which could be very long)
(e.g. in some process-manager). Coredump and exit process events
are perfect for such use cases (see 2b5faa4c553f "connector: Added
coredumping event to the process connector").

The problem is that for now the process-manager cannot know the parent
of a dying process using connectors. This could be useful if the
process-manager should monitor for failures only children of certain
parents, so we could filter the coredump and exit events by parent
process and/or thread ID.

Add parent pid and tgid to coredump and exit process connectors event
data.

Signed-off-by: Stefan Strogin <sstrogin@cisco.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/connector/cn_proc.c

@@ -262,6 +262,8 @@ void proc_coredump_connector(struct task_struct *task)
 	ev->what = PROC_EVENT_COREDUMP;
 	ev->event_data.coredump.process_pid = task->pid;
 	ev->event_data.coredump.process_tgid = task->tgid;
+	ev->event_data.coredump.parent_pid = task->real_parent->pid;
+	ev->event_data.coredump.parent_tgid = task->real_parent->tgid;
 
 	memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 	msg->ack = 0; /* not used */
@@ -288,6 +290,8 @@ void proc_exit_connector(struct task_struct *task)
 	ev->event_data.exit.process_tgid = task->tgid;
 	ev->event_data.exit.exit_code = task->exit_code;
 	ev->event_data.exit.exit_signal = task->exit_signal;
+	ev->event_data.exit.parent_pid = task->real_parent->pid;
+	ev->event_data.exit.parent_tgid = task->real_parent->tgid;
 
 	memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 	msg->ack = 0; /* not used */

include/uapi/linux/cn_proc.h

@@ -116,12 +116,16 @@ struct proc_event {
 		struct coredump_proc_event {
 			__kernel_pid_t process_pid;
 			__kernel_pid_t process_tgid;
+			__kernel_pid_t parent_pid;
+			__kernel_pid_t parent_tgid;
 		} coredump;
 
 		struct exit_proc_event {
 			__kernel_pid_t process_pid;
 			__kernel_pid_t process_tgid;
 			__u32 exit_code, exit_signal;
+			__kernel_pid_t parent_pid;
+			__kernel_pid_t parent_tgid;
 		} exit;
 
 	} event_data;