X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fsignal.c;h=6c0958e52ea7bdac212353c2b42bbd59e702ce45;hb=de08341a0ef747d607542af3ae441b286f503e35;hp=8423867f7d8f0c3b1eb8be57657a55d0c0a1612f;hpb=021e1ae3d85a76ce962a300c96813f04ae50c87c;p=linux-2.6

diff --git a/kernel/signal.c b/kernel/signal.c
index 8423867f7d..6c0958e52e 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -231,6 +231,40 @@ void flush_signals(struct task_struct *t)
 	spin_unlock_irqrestore(&t->sighand->siglock, flags);
 }
 
+static void __flush_itimer_signals(struct sigpending *pending)
+{
+	sigset_t signal, retain;
+	struct sigqueue *q, *n;
+
+	signal = pending->signal;
+	sigemptyset(&retain);
+
+	list_for_each_entry_safe(q, n, &pending->list, list) {
+		int sig = q->info.si_signo;
+
+		if (likely(q->info.si_code != SI_TIMER)) {
+			sigaddset(&retain, sig);
+		} else {
+			sigdelset(&signal, sig);
+			list_del_init(&q->list);
+			__sigqueue_free(q);
+		}
+	}
+
+	sigorsets(&pending->signal, &signal, &retain);
+}
+
+void flush_itimer_signals(void)
+{
+	struct task_struct *tsk = current;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tsk->sighand->siglock, flags);
+	__flush_itimer_signals(&tsk->pending);
+	__flush_itimer_signals(&tsk->signal->shared_pending);
+	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+}
+
 void ignore_signals(struct task_struct *t)
 {
 	int i;
@@ -533,6 +567,7 @@ static int rm_from_queue(unsigned long mask, struct sigpending *s)
 static int check_kill_permission(int sig, struct siginfo *info,
 				 struct task_struct *t)
 {
+	struct pid *sid;
 	int error;
 
 	if (!valid_signal(sig))
@@ -545,11 +580,22 @@ static int check_kill_permission(int sig, struct siginfo *info,
 	if (error)
 		return error;
 
-	if (((sig != SIGCONT) || (task_session_nr(current) != task_session_nr(t)))
-	    && (current->euid ^ t->suid) && (current->euid ^ t->uid)
-	    && (current->uid ^ t->suid) && (current->uid ^ t->uid)
-	    && !capable(CAP_KILL))
-		return -EPERM;
+	if ((current->euid ^ t->suid) && (current->euid ^ t->uid) &&
+	    (current->uid  ^ t->suid) && (current->uid  ^ t->uid) &&
+	    !capable(CAP_KILL)) {
+		switch (sig) {
+		case SIGCONT:
+			sid = task_session(t);
+			/*
+			 * We don't return the error if sid == NULL. The
+			 * task was unhashed, the caller must notice this.
+			 */
+			if (!sid || sid == task_session(current))
+				break;
+		default:
+			return -EPERM;
+		}
+	}
 
 	return security_task_kill(t, info, sig, 0);
 }
@@ -716,7 +762,8 @@ static void complete_signal(int sig, struct task_struct *p, int group)
 	 * Found a killable thread.  If the signal will be fatal,
 	 * then start taking the whole group down immediately.
 	 */
-	if (sig_fatal(p, sig) && !(signal->flags & SIGNAL_GROUP_EXIT) &&
+	if (sig_fatal(p, sig) &&
+	    !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
 	    !sigismember(&t->real_blocked, sig) &&
 	    (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {
 		/*
@@ -772,13 +819,6 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
 	 */
 	if (legacy_queue(pending, sig))
 		return 0;
-
-	/*
-	 * Deliver the signal to listening signalfds. This must be called
-	 * with the sighand lock held.
-	 */
-	signalfd_notify(t, sig);
-
 	/*
 	 * fast-pathed signals for kernel-internal things like SIGSTOP
 	 * or SIGKILL.
@@ -828,6 +868,7 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
 	}
 
 out_set:
+	signalfd_notify(t, sig);
 	sigaddset(&pending->signal, sig);
 	complete_signal(sig, t, group);
 	return 0;
@@ -885,7 +926,8 @@ specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
  * since we do not want to have a signal handler that was blocked
  * be invoked when user space had explicitly blocked it.
  *
- * We don't want to have recursive SIGSEGV's etc, for example.
+ * We don't want to have recursive SIGSEGV's etc, for example,
+ * that is why we also clear SIGNAL_UNKILLABLE.
  */
 int
 force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
@@ -905,6 +947,8 @@ force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
 			recalc_sigpending_and_wake(t);
 		}
 	}
+	if (action->sa.sa_handler == SIG_DFL)
+		t->signal->flags &= ~SIGNAL_UNKILLABLE;
 	ret = specific_send_sig_info(sig, info, t);
 	spin_unlock_irqrestore(&t->sighand->siglock, flags);
 
@@ -1230,17 +1274,22 @@ void sigqueue_free(struct sigqueue *q)
 
 	BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
 	/*
-	 * If the signal is still pending remove it from the
-	 * pending queue. We must hold ->siglock while testing
-	 * q->list to serialize with collect_signal().
+	 * We must hold ->siglock while testing q->list
+	 * to serialize with collect_signal() or with
+	 * __exit_signal()->flush_sigqueue().
 	 */
 	spin_lock_irqsave(lock, flags);
+	q->flags &= ~SIGQUEUE_PREALLOC;
+	/*
+	 * If it is queued it will be freed when dequeued,
+	 * like the "regular" sigqueue.
+	 */
 	if (!list_empty(&q->list))
-		list_del_init(&q->list);
+		q = NULL;
 	spin_unlock_irqrestore(lock, flags);
 
-	q->flags &= ~SIGQUEUE_PREALLOC;
-	__sigqueue_free(q);
+	if (q)
+		__sigqueue_free(q);
 }
 
 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
@@ -1609,7 +1658,8 @@ static int do_signal_stop(int signr)
 	} else {
 		struct task_struct *t;
 
-		if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
+		if (unlikely((sig->flags & (SIGNAL_STOP_DEQUEUED | SIGNAL_UNKILLABLE))
+					 != SIGNAL_STOP_DEQUEUED) ||
 		    unlikely(signal_group_exit(sig)))
 			return 0;
 		/*
@@ -1755,7 +1805,8 @@ relock:
 		/*
 		 * Global init gets no signals it doesn't want.
 		 */
-		if (is_global_init(current))
+		if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
+		    !signal_group_exit(signal))
 			continue;
 
 		if (sig_kernel_stop(signr)) {
@@ -2529,7 +2580,7 @@ asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
 
 	current->state = TASK_INTERRUPTIBLE;
 	schedule();
-	set_thread_flag(TIF_RESTORE_SIGMASK);
+	set_restore_sigmask();
 	return -ERESTARTNOHAND;
 }
 #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */