Function pipe_fops_write

components/drivers/ipc/pipe.c:284–342

static ssize_t pipe_fops_write(struct dfs_file *fd, const void *buf, size_t count, off_t *pos)
#else
static ssize_t pipe_fops_write(struct dfs_file *fd, const void *buf, size_t count)
#endif
{
    int len;
    rt_pipe_t *pipe;
    int wakeup = 0;
    int ret = 0;
    uint8_t *pbuf;

    pipe = (rt_pipe_t *)fd->vnode->data;

    if (count == 0)
    {
        return 0;
    }

    pbuf = (uint8_t*)buf;
    rt_mutex_take(&pipe->lock, -1);

    while (1)
    {
        len = rt_ringbuffer_put(pipe->fifo, pbuf, count - ret);
        ret +=  len;
        pbuf += len;
        wakeup = 1;

        if (ret == count)
        {
            break;
        }
        else
        {
            if (fd->flags & O_NONBLOCK)
            {
                if (ret == 0)
                {
                    ret = -EAGAIN;
                }

                break;
            }
        }

        rt_mutex_release(&pipe->lock);
        rt_wqueue_wakeup(&pipe->reader_queue, (void*)POLLIN);
        /* pipe full, waiting on suspended write list */
        if (rt_wqueue_wait_interruptible(&pipe->writer_queue, 0, -1) == -RT_EINTR)
            return -EINTR;
        rt_mutex_take(&pipe->lock, -1);
    }
    rt_mutex_release(&pipe->lock);

    if (wakeup)
    {
        rt_wqueue_wakeup(&pipe->reader_queue, (void*)POLLIN);
    }

    return ret;