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Commit fa00b80b authored by Roland McGrath's avatar Roland McGrath Committed by Linus Torvalds
Browse files

tracehook: job control 



This defines the tracehook_notify_jctl() hook to formalize the ptrace
effects on the job control notifications.  There is no change, only
cleanup.

Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7bcf6a2c

include/linux/tracehook.h

+20 −0
Original line number Diff line number Diff line
@@ -451,4 +451,24 @@ static inline int tracehook_get_signal(struct task_struct *task, 
	return 0;

}



/**

 * tracehook_notify_jctl - report about job control stop/continue

 * @notify:		nonzero if this is the last thread in the group to stop

 * @why:		%CLD_STOPPED or %CLD_CONTINUED

 *

 * This is called when we might call do_notify_parent_cldstop().

 * It's called when about to stop for job control; we are already in

 * %TASK_STOPPED state, about to call schedule().  It's also called when

 * a delayed %CLD_STOPPED or %CLD_CONTINUED report is ready to be made.

 *

 * Return nonzero to generate a %SIGCHLD with @why, which is

 * normal if @notify is nonzero.

 *

 * Called with no locks held.

 */

static inline int tracehook_notify_jctl(int notify, int why)

{

	return notify || (current->ptrace & PT_PTRACED);

}



#endif	/* <linux/tracehook.h> */

kernel/signal.c

+5 −5
Original line number Diff line number Diff line
@@ -596,9 +596,6 @@ static int check_kill_permission(int sig, struct siginfo *info, 
	return security_task_kill(t, info, sig, 0);

}



/* forward decl */

static void do_notify_parent_cldstop(struct task_struct *tsk, int why);



/*

 * Handle magic process-wide effects of stop/continue signals. Unlike

 * the signal actions, these happen immediately at signal-generation
@@ -1605,7 +1602,7 @@ finish_stop(int stop_count) 
	 * a group stop in progress and we are the last to stop,

	 * report to the parent.  When ptraced, every thread reports itself.

	 */

	if (stop_count == 0 || (current->ptrace & PT_PTRACED)) {

	if (tracehook_notify_jctl(stop_count == 0, CLD_STOPPED)) {

		read_lock(&tasklist_lock);

		do_notify_parent_cldstop(current, CLD_STOPPED);

		read_unlock(&tasklist_lock);
@@ -1741,6 +1738,9 @@ relock: 
		signal->flags &= ~SIGNAL_CLD_MASK;

		spin_unlock_irq(&sighand->siglock);



		if (unlikely(!tracehook_notify_jctl(1, why)))

			goto relock;



		read_lock(&tasklist_lock);

		do_notify_parent_cldstop(current->group_leader, why);

		read_unlock(&tasklist_lock);
@@ -1906,7 +1906,7 @@ void exit_signals(struct task_struct *tsk) 
out:

	spin_unlock_irq(&tsk->sighand->siglock);



	if (unlikely(group_stop)) {

	if (unlikely(group_stop) && tracehook_notify_jctl(1, CLD_STOPPED)) {

		read_lock(&tasklist_lock);

		do_notify_parent_cldstop(tsk, CLD_STOPPED);

		read_unlock(&tasklist_lock);