From: Roland McGrath <roland@redhat.com>
All extant uses of `notify_parent' are for ptrace stops, unless it is used
by external modules that I have not seen. This patch tightens up some of
the signal code by making notify_parent only work for the stopped case.
That means that do_notify_parent is exclusively used for the dead case and
doesn't need to check for the stopped case. The only outward effect of
this is to make ptrace stops (i.e. notify_parent calls) obey the
SA_NOCLDSTOP behavior instead of incorrectly checking SA_NOCLDWAIT. I'm
sure no ptrace user actually sets SA_NOCLDSTOP, so it won't be noticed in
reality at all.
Also, no modules now need notify_parent(), so remove its export.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/kernel/signal.c | 59 +++++++++++++++++++-----------------------------
1 files changed, 24 insertions(+), 35 deletions(-)
diff -puN kernel/signal.c~notify_parent-cleanup kernel/signal.c
--- 25/kernel/signal.c~notify_parent-cleanup Thu Aug 19 14:28:38 2004
+++ 25-akpm/kernel/signal.c Thu Aug 19 14:29:02 2004
@@ -1441,19 +1441,22 @@ static void __wake_up_parent(struct task
}
/*
- * Let a parent know about a status change of a child.
+ * Let a parent know about the death of a child.
+ * For a stopped/continued status change, use do_notify_parent_cldstop instead.
*/
void do_notify_parent(struct task_struct *tsk, int sig)
{
struct siginfo info;
unsigned long flags;
- int why, status;
struct sighand_struct *psig;
if (sig == -1)
BUG();
+ /* do_notify_parent_cldstop should have been called instead. */
+ BUG_ON(tsk->state == TASK_STOPPED);
+
BUG_ON(tsk->group_leader != tsk && tsk->group_leader->state != TASK_ZOMBIE && !tsk->ptrace);
BUG_ON(tsk->group_leader == tsk && !thread_group_empty(tsk) && !tsk->ptrace);
@@ -1467,34 +1470,19 @@ void do_notify_parent(struct task_struct
info.si_stime = tsk->stime;
k_getrusage(tsk, RUSAGE_BOTH, &info.si_rusage);
- status = tsk->exit_code & 0x7f;
- why = SI_KERNEL; /* shouldn't happen */
- switch (tsk->state) {
- case TASK_STOPPED:
- /* FIXME -- can we deduce CLD_TRAPPED or CLD_CONTINUED? */
- if (tsk->ptrace & PT_PTRACED)
- why = CLD_TRAPPED;
- else
- why = CLD_STOPPED;
- break;
-
- default:
- if (tsk->exit_code & 0x80)
- why = CLD_DUMPED;
- else if (tsk->exit_code & 0x7f)
- why = CLD_KILLED;
- else {
- why = CLD_EXITED;
- status = tsk->exit_code >> 8;
- }
- break;
+ info.si_status = tsk->exit_code & 0x7f;
+ if (tsk->exit_code & 0x80)
+ info.si_code = CLD_DUMPED;
+ else if (tsk->exit_code & 0x7f)
+ info.si_code = CLD_KILLED;
+ else {
+ info.si_code = CLD_EXITED;
+ info.si_status = tsk->exit_code >> 8;
}
- info.si_code = why;
- info.si_status = status;
psig = tsk->parent->sighand;
spin_lock_irqsave(&psig->siglock, flags);
- if (sig == SIGCHLD && tsk->state != TASK_STOPPED &&
+ if (sig == SIGCHLD &&
(psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
(psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
/*
@@ -1525,19 +1513,19 @@ void do_notify_parent(struct task_struct
/*
* We need the tasklist lock because it's the only
- * thing that protects out "parent" pointer.
+ * thing that protects our "parent" pointer.
*
- * exit.c calls "do_notify_parent()" directly, because
- * it already has the tasklist lock.
+ * This entrypoint was once used in other ways, but now it is
+ * only ever called as "notify_parent(current, SIGCHLD)" after
+ * entering TASK_STOPPED state.
*/
void
notify_parent(struct task_struct *tsk, int sig)
{
- if (sig != -1) {
- read_lock(&tasklist_lock);
- do_notify_parent(tsk, sig);
- read_unlock(&tasklist_lock);
- }
+ BUG_ON(sig != SIGCHLD);
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(tsk, tsk->parent);
+ read_unlock(&tasklist_lock);
}
static void
@@ -1562,6 +1550,8 @@ do_notify_parent_cldstop(struct task_str
if (info.si_status == 0) {
info.si_status = SIGCONT;
info.si_code = CLD_CONTINUED;
+ } else if (tsk->ptrace & PT_PTRACED) {
+ info.si_code = CLD_TRAPPED;
} else {
info.si_code = CLD_STOPPED;
}
@@ -1929,7 +1919,6 @@ EXPORT_SYMBOL(kill_proc);
EXPORT_SYMBOL(kill_proc_info);
EXPORT_SYMBOL(kill_sl);
EXPORT_SYMBOL(kill_sl_info);
-EXPORT_SYMBOL(notify_parent);
EXPORT_SYMBOL(send_sig);
EXPORT_SYMBOL(send_sig_info);
EXPORT_SYMBOL(send_group_sig_info);
_