static ssize_t uinput_events_to_user(struct uinput_device *udev,
char __user *buffer, size_t count)
{
struct input_event event;
size_t read = 0;
while (read + input_event_size() <= count &&
uinput_fetch_next_event(udev, &event)) {
if (input_event_to_user(buffer + read, &event))
return -EFAULT;
read += input_event_size();
}
return read;
}
static ssize_t uinput_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
struct uinput_device *udev = file->private_data;
int retval = 0;
if (udev->state != UIST_CREATED)
return -ENODEV;
if (udev->head == udev->tail && (file->f_flags & O_NONBLOCK))
return -EAGAIN;
retval = wait_event_interruptible(udev->waitq,
udev->head != udev->tail || udev->state != UIST_CREATED);
if (retval)
return retval;
retval = mutex_lock_interruptible(&udev->mutex);
if (retval)
return retval;
if (udev->state != UIST_CREATED) {
retval = -ENODEV;
goto out;
}
while (udev->head != udev->tail && retval + input_event_size() <= count) {
if (input_event_to_user(buffer + retval, &udev->buff[udev->tail])) {
retval = -EFAULT;
goto out;
}
udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE;
retval += input_event_size();
}
out:
mutex_unlock(&udev->mutex);
return retval;
}