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tracehook: job control

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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: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Roland McGrath
2008-07-25 19:45:54 -07:00
committed by Linus Torvalds
parent 7bcf6a2ca5
commit fa00b80b3c
2 changed files with 25 additions and 5 deletions
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20
include/linux/tracehook.h
View File

@@ -451,4 +451,24 @@ static inline int tracehook_get_signal(struct task_struct *task,
return 0; 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> */ #endif /* <linux/tracehook.h> */

10
kernel/signal.c
View File

@@ -596,9 +596,6 @@ static int check_kill_permission(int sig, struct siginfo *info,
return security_task_kill(t, info, sig, 0); 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 * Handle magic process-wide effects of stop/continue signals. Unlike
* the signal actions, these happen immediately at signal-generation * 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, * a group stop in progress and we are the last to stop,
* report to the parent. When ptraced, every thread reports itself. * 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); read_lock(&tasklist_lock);
do_notify_parent_cldstop(current, CLD_STOPPED); do_notify_parent_cldstop(current, CLD_STOPPED);
read_unlock(&tasklist_lock); read_unlock(&tasklist_lock);
@@ -1741,6 +1738,9 @@ relock:
signal->flags &= ~SIGNAL_CLD_MASK; signal->flags &= ~SIGNAL_CLD_MASK;
spin_unlock_irq(&sighand->siglock); spin_unlock_irq(&sighand->siglock);
if (unlikely(!tracehook_notify_jctl(1, why)))
goto relock;
read_lock(&tasklist_lock); read_lock(&tasklist_lock);
do_notify_parent_cldstop(current->group_leader, why); do_notify_parent_cldstop(current->group_leader, why);
read_unlock(&tasklist_lock); read_unlock(&tasklist_lock);
@@ -1906,7 +1906,7 @@ void exit_signals(struct task_struct *tsk)
out: out:
spin_unlock_irq(&tsk->sighand->siglock); spin_unlock_irq(&tsk->sighand->siglock);
if (unlikely(group_stop)) { if (unlikely(group_stop) && tracehook_notify_jctl(1, CLD_STOPPED)) {
read_lock(&tasklist_lock); read_lock(&tasklist_lock);
do_notify_parent_cldstop(tsk, CLD_STOPPED); do_notify_parent_cldstop(tsk, CLD_STOPPED);
read_unlock(&tasklist_lock); read_unlock(&tasklist_lock);