C++ destroy_hrtimer_on_stack函数代码示例

long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
{
	struct hrtimer_sleeper t;
	struct timespec __user  *rmtp;
	int ret = 0;

	hrtimer_init_on_stack(&t.timer, restart->nanosleep.index,
				HRTIMER_MODE_ABS);
	hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);

	if (do_nanosleep(&t, HRTIMER_MODE_ABS))
		goto out;

	rmtp = restart->nanosleep.rmtp;
	if (rmtp) {
		ret = update_rmtp(&t.timer, rmtp);
		if (ret <= 0)
			goto out;
	}

	/* The other values in restart are already filled in */
	ret = -ERESTART_RESTARTBLOCK;
out:
	destroy_hrtimer_on_stack(&t.timer);
	return ret;
}

long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
		       const enum hrtimer_mode mode, const clockid_t clockid)
{
	struct restart_block *restart;
	struct hrtimer_sleeper t;
	int ret = 0;

	hrtimer_init_on_stack(&t.timer, clockid, mode);
	t.timer.expires = timespec_to_ktime(*rqtp);
	if (do_nanosleep(&t, mode))
		goto out;

	/* Absolute timers do not update the rmtp value and restart: */
	if (mode == HRTIMER_MODE_ABS) {
		ret = -ERESTARTNOHAND;
		goto out;
	}

	if (rmtp) {
		ret = update_rmtp(&t.timer, rmtp);
		if (ret <= 0)
			goto out;
	}

	restart = &current_thread_info()->restart_block;
	restart->fn = hrtimer_nanosleep_restart;
	restart->nanosleep.index = t.timer.base->index;
	restart->nanosleep.rmtp = rmtp;
	restart->nanosleep.expires = t.timer.expires.tv64;

	ret = -ERESTART_RESTARTBLOCK;
out:
	destroy_hrtimer_on_stack(&t.timer);
	return ret;
}

static long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
{
	struct hrtimer_sleeper t;
	int ret;

	hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid,
				HRTIMER_MODE_ABS);
	hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);

	ret = do_nanosleep(&t, HRTIMER_MODE_ABS);
	destroy_hrtimer_on_stack(&t.timer);
	return ret;
}

int sched_wait_interval(int flags, const struct timespec __user * rqtp, struct timespec __user * rmtp) {
    struct hrtimer_sleeper t;
    enum hrtimer_mode mode = flags & TIMER_ABSTIME ?
                             HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
    int ret = 0;

    hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, mode);
    hrtimer_set_expires(&t.timer, timespec_to_ktime(*rqtp));
    hrtimer_init_sleeper(&t, current);

    do {
        set_current_state(TASK_INTERRUPTIBLE);
        hrtimer_start_expires(&t.timer, mode);
        if (!hrtimer_active(&t.timer))
            t.task = NULL;

        if (likely(t.task)) {
            t.task->dl.flags |= DL_NEW;
            schedule();
        }
        hrtimer_cancel(&t.timer);
        mode = HRTIMER_MODE_ABS;
    } while (t.task && !signal_pending(current));
    __set_current_state(TASK_RUNNING);

    if (t.task == NULL)
        goto out;

    if (mode == HRTIMER_MODE_ABS) {
        ret = -ERESTARTNOHAND;
        goto out;
    }

    if (rmtp) {
        ktime_t rmt;
        struct timespec rmt_ts;
        rmt = hrtimer_expires_remaining(&t.timer);
        if (rmt.tv64 > 0)
            goto out;
        rmt_ts = ktime_to_timespec(rmt);
        if (!timespec_valid(&rmt_ts))
            goto out;
        *rmtp = rmt_ts;
    }
out:
    destroy_hrtimer_on_stack(&t.timer);
    return ret;
}

/**
 * schedule_hrtimeout_range_clock - sleep until timeout
 * @expires:	timeout value (ktime_t)
 * @delta:	slack in expires timeout (ktime_t)
 * @mode:	timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
 * @clock:	timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
 */
int __sched
schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta,
			       const enum hrtimer_mode mode, int clock)
{
	struct hrtimer_sleeper t;

	/*
	 * Optimize when a zero timeout value is given. It does not
	 * matter whether this is an absolute or a relative time.
	 */
	if (expires && !expires->tv64) {
		__set_current_state(TASK_RUNNING);
		return 0;
	}

	/*
	 * A NULL parameter means "infinite"
	 */
	if (!expires) {
		schedule();
		__set_current_state(TASK_RUNNING);
		return -EINTR;
	}

	hrtimer_init_on_stack(&t.timer, clock, mode);
	hrtimer_set_expires_range_ns(&t.timer, *expires, delta);

	hrtimer_init_sleeper(&t, current);

	hrtimer_start_expires(&t.timer, mode);
	if (!hrtimer_active(&t.timer))
		t.task = NULL;

	if (likely(t.task))
		schedule();

	hrtimer_cancel(&t.timer);
	destroy_hrtimer_on_stack(&t.timer);

	__set_current_state(TASK_RUNNING);

	return !t.task ? 0 : -EINTR;
}

long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
		       const enum hrtimer_mode mode, const clockid_t clockid)
{
	struct restart_block *restart;
	struct hrtimer_sleeper t;
	int ret = 0;
	unsigned long slack;

	slack = current->timer_slack_ns;
	if (rt_task(current))
		slack = 0;

	hrtimer_init_on_stack(&t.timer, clockid, mode);
	hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
	if (do_nanosleep(&t, mode))
		goto out;

	/* Absolute timers do not update the rmtp value and restart: */
	if (mode == HRTIMER_MODE_ABS) {
		ret = -ERESTARTNOHAND;
		goto out;
	}

	if (rmtp) {
		ret = update_rmtp(&t.timer, rmtp);
		if (ret <= 0)
			goto out;
	}

	restart = &current_thread_info()->restart_block;
	restart->fn = hrtimer_nanosleep_restart;
	restart->nanosleep.clockid = t.timer.base->clockid;
	restart->nanosleep.rmtp = rmtp;
	restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);

	ret = -ERESTART_RESTARTBLOCK;
out:
	destroy_hrtimer_on_stack(&t.timer);
	return ret;
}

//.........这里部分代码省略.........
	ret = -EWOULDBLOCK;
	if (unlikely(uval != val)) {
		queue_unlock(&q, hb);
		goto out_put_key;
	}

	/* Only actually queue if *uaddr contained val.  */
	queue_me(&q, hb);

	/*
	 * There might have been scheduling since the queue_me(), as we
	 * cannot hold a spinlock across the get_user() in case it
	 * faults, and we cannot just set TASK_INTERRUPTIBLE state when
	 * queueing ourselves into the futex hash.  This code thus has to
	 * rely on the futex_wake() code removing us from hash when it
	 * wakes us up.
	 */

	/* add_wait_queue is the barrier after __set_current_state. */
	__set_current_state(TASK_INTERRUPTIBLE);
	add_wait_queue(&q.waiter, &wait);
	/*
	 * !plist_node_empty() is safe here without any lock.
	 * q.lock_ptr != 0 is not safe, because of ordering against wakeup.
	 */
	if (likely(!plist_node_empty(&q.list))) {
		if (!abs_time)
			schedule();
		else {
			hrtimer_init_on_stack(&t.timer,
					      clockrt ? CLOCK_REALTIME :
					      CLOCK_MONOTONIC,
					      HRTIMER_MODE_ABS);
			hrtimer_init_sleeper(&t, current);
			hrtimer_set_expires_range_ns(&t.timer, *abs_time,
						     current->timer_slack_ns);

			hrtimer_start_expires(&t.timer, HRTIMER_MODE_ABS);
			if (!hrtimer_active(&t.timer))
				t.task = NULL;

			/*
			 * the timer could have already expired, in which
			 * case current would be flagged for rescheduling.
			 * Don't bother calling schedule.
			 */
			if (likely(t.task))
				schedule();

			hrtimer_cancel(&t.timer);

			/* Flag if a timeout occured */
			rem = (t.task == NULL);

			destroy_hrtimer_on_stack(&t.timer);
		}
	}
	__set_current_state(TASK_RUNNING);

	/*
	 * NOTE: we don't remove ourselves from the waitqueue because
	 * we are the only user of it.
	 */

	/* If we were woken (and unqueued), we succeeded, whatever. */
	ret = 0;
	if (!unqueue_me(&q))
		goto out_put_key;
	ret = -ETIMEDOUT;
	if (rem)
		goto out_put_key;

	/*
	 * We expect signal_pending(current), but another thread may
	 * have handled it for us already.
	 */
	ret = -ERESTARTSYS;
	if (!abs_time)
		goto out_put_key;

	restart = &current_thread_info()->restart_block;
	restart->fn = CVE_2014_0205_linux2_6_30_2_futex_wait_restart;
	restart->futex.uaddr = (u32 *)uaddr;
	restart->futex.val = val;
	restart->futex.time = abs_time->tv64;
	restart->futex.bitset = bitset;
	restart->futex.flags = 0;

	if (fshared)
		restart->futex.flags |= FLAGS_SHARED;
	if (clockrt)
		restart->futex.flags |= FLAGS_CLOCKRT;

	ret = -ERESTART_RESTARTBLOCK;

out_put_key:
	put_futex_key(fshared, &q.key);
out:
	return ret;
}