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tracehook: death

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This moves the ptrace logic in task death (exit_notify) into tracehook.h
inlines.  Some code is rearranged slightly to make things nicer.  There is
no change, only cleanup.

There is one hook called with the tasklist_lock write-locked, as ptrace
needs.  There is also a new hook called after exit_state changes and
without locks.  This is a better place for tracing work to be in the
future, since it doesn't delay the whole system with locking.

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 fa00b80b3c
commit 2b2a1ff64a
4 changed files with 69 additions and 21 deletions
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52
include/linux/tracehook.h
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@@ -471,4 +471,56 @@ static inline int tracehook_notify_jctl(int notify, int why)
return notify || (current->ptrace & PT_PTRACED);
}
/**
* tracehook_notify_death - task is dead, ready to notify parent
* @task: @current task now exiting
* @death_cookie: value to pass to tracehook_report_death()
* @group_dead: nonzero if this was the last thread in the group to die
*
* Return the signal number to send our parent with do_notify_parent(), or
* zero to send no signal and leave a zombie, or -1 to self-reap right now.
*
* Called with write_lock_irq(&tasklist_lock) held.
*/
static inline int tracehook_notify_death(struct task_struct *task,
void **death_cookie, int group_dead)
{
if (task->exit_signal == -1)
return task->ptrace ? SIGCHLD : -1;
/*
* If something other than our normal parent is ptracing us, then
* send it a SIGCHLD instead of honoring exit_signal. exit_signal
* only has special meaning to our real parent.
*/
if (thread_group_empty(task) && !ptrace_reparented(task))
return task->exit_signal;
return task->ptrace ? SIGCHLD : 0;
}
/**
* tracehook_report_death - task is dead and ready to be reaped
* @task: @current task now exiting
* @signal: signal number sent to parent, or 0 or -1
* @death_cookie: value passed back from tracehook_notify_death()
* @group_dead: nonzero if this was the last thread in the group to die
*
* Thread has just become a zombie or is about to self-reap. If positive,
* @signal is the signal number just sent to the parent (usually %SIGCHLD).
* If @signal is -1, this thread will self-reap. If @signal is 0, this is
* a delayed_group_leader() zombie. The @death_cookie was passed back by
* tracehook_notify_death().
*
* If normal reaping is not inhibited, @task->exit_state might be changing
* in parallel.
*
* Called without locks.
*/
static inline void tracehook_report_death(struct task_struct *task,
int signal, void *death_cookie,
int group_dead)
{
}
#endif /* <linux/tracehook.h> */