Logo Search packages:      
Sourcecode: linux version File versions  Download package

hidraw.c

/*
 * HID raw devices, giving access to raw HID events.
 *
 * In comparison to hiddev, this device does not process the
 * hid events at all (no parsing, no lookups). This lets applications
 * to work on raw hid events as they want to, and avoids a need to
 * use a transport-specific userspace libhid/libusb libraries.
 *
 *  Copyright (c) 2007 Jiri Kosina
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <linux/fs.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/cdev.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/major.h>
#include <linux/hid.h>
#include <linux/mutex.h>

#include <linux/hidraw.h>

static int hidraw_major;
static struct cdev hidraw_cdev;
static struct class *hidraw_class;
static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
static DEFINE_SPINLOCK(minors_lock);

static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
      struct hidraw_list *list = file->private_data;
      int ret = 0, len;
      char *report;
      DECLARE_WAITQUEUE(wait, current);

      while (ret == 0) {

            mutex_lock(&list->read_mutex);

            if (list->head == list->tail) {
                  add_wait_queue(&list->hidraw->wait, &wait);
                  set_current_state(TASK_INTERRUPTIBLE);

                  while (list->head == list->tail) {
                        if (file->f_flags & O_NONBLOCK) {
                              ret = -EAGAIN;
                              break;
                        }
                        if (signal_pending(current)) {
                              ret = -ERESTARTSYS;
                              break;
                        }
                        if (!list->hidraw->exist) {
                              ret = -EIO;
                              break;
                        }

                        /* allow O_NONBLOCK to work well from other threads */
                        mutex_unlock(&list->read_mutex);
                        schedule();
                        mutex_lock(&list->read_mutex);
                        set_current_state(TASK_INTERRUPTIBLE);
                  }

                  set_current_state(TASK_RUNNING);
                  remove_wait_queue(&list->hidraw->wait, &wait);
            }

            if (ret)
                  goto out;

            report = list->buffer[list->tail].value;
            len = list->buffer[list->tail].len > count ?
                  count : list->buffer[list->tail].len;

            if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
                  ret = -EFAULT;
                  goto out;
            }
            ret += len;

            kfree(list->buffer[list->tail].value);
            list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
      }
out:
      mutex_unlock(&list->read_mutex);
      return ret;
}

/* the first byte is expected to be a report number */
static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
      unsigned int minor = iminor(file->f_path.dentry->d_inode);
      struct hid_device *dev = hidraw_table[minor]->hid;
      __u8 *buf;
      int ret = 0;

      if (!dev->hid_output_raw_report)
            return -ENODEV;

      if (count > HID_MIN_BUFFER_SIZE) {
            printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
                        task_pid_nr(current));
            return -EINVAL;
      }

      if (count < 2) {
            printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
                        task_pid_nr(current));
            return -EINVAL;
      }

      buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
      if (!buf)
            return -ENOMEM;

      if (copy_from_user(buf, buffer, count)) {
            ret = -EFAULT;
            goto out;
      }

      ret = dev->hid_output_raw_report(dev, buf, count);
out:
      kfree(buf);
      return ret;
}

static unsigned int hidraw_poll(struct file *file, poll_table *wait)
{
      struct hidraw_list *list = file->private_data;

      poll_wait(file, &list->hidraw->wait, wait);
      if (list->head != list->tail)
            return POLLIN | POLLRDNORM;
      if (!list->hidraw->exist)
            return POLLERR | POLLHUP;
      return 0;
}

static int hidraw_open(struct inode *inode, struct file *file)
{
      unsigned int minor = iminor(inode);
      struct hidraw *dev;
      struct hidraw_list *list;
      int err = 0;

      if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
            err = -ENOMEM;
            goto out;
      }

      spin_lock(&minors_lock);
      if (!hidraw_table[minor]) {
            printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
                        minor);
            kfree(list);
            err = -ENODEV;
            goto out_unlock;
      }

      list->hidraw = hidraw_table[minor];
      mutex_init(&list->read_mutex);
      list_add_tail(&list->node, &hidraw_table[minor]->list);
      file->private_data = list;

      dev = hidraw_table[minor];
      if (!dev->open++)
            dev->hid->hid_open(dev->hid);

out_unlock:
      spin_unlock(&minors_lock);
out:
      return err;

}

static int hidraw_release(struct inode * inode, struct file * file)
{
      unsigned int minor = iminor(inode);
      struct hidraw *dev;
      struct hidraw_list *list = file->private_data;

      if (!hidraw_table[minor]) {
            printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
                        minor);
            return -ENODEV;
      }

      list_del(&list->node);
      dev = hidraw_table[minor];
      if (!dev->open--) {
            if (list->hidraw->exist)
                  dev->hid->hid_close(dev->hid);
            else
                  kfree(list->hidraw);
      }

      return 0;
}

static int hidraw_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
      unsigned int minor = iminor(inode);
      struct hidraw *dev = hidraw_table[minor];
      void __user *user_arg = (void __user*) arg;

      switch (cmd) {
            case HIDIOCGRDESCSIZE:
                  if (put_user(dev->hid->rsize, (int __user *)arg))
                        return -EFAULT;
                  return 0;

            case HIDIOCGRDESC:
                  {
                        __u32 len;

                        if (get_user(len, (int __user *)arg))
                              return -EFAULT;

                        if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
                              return -EINVAL;

                        if (copy_to_user(user_arg + offsetof(
                                                struct hidraw_report_descriptor,
                                                value[0]),
                                          dev->hid->rdesc,
                                          min(dev->hid->rsize, len)))
                                    return -EFAULT;
                        return 0;
                  }
            case HIDIOCGRAWINFO:
                  {
                        struct hidraw_devinfo dinfo;

                        dinfo.bustype = dev->hid->bus;
                        dinfo.vendor = dev->hid->vendor;
                        dinfo.product = dev->hid->product;
                        if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
                              return -EFAULT;

                        return 0;
                  }
            default:
                  printk(KERN_EMERG "hidraw: unsupported ioctl() %x\n",
                              cmd);
      }
      return -EINVAL;
}

static const struct file_operations hidraw_ops = {
      .owner =        THIS_MODULE,
      .read =         hidraw_read,
      .write =        hidraw_write,
      .poll =         hidraw_poll,
      .open =         hidraw_open,
      .release =      hidraw_release,
      .ioctl =        hidraw_ioctl,
};

void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
{
      struct hidraw *dev = hid->hidraw;
      struct hidraw_list *list;

      list_for_each_entry(list, &dev->list, node) {
            list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
            list->buffer[list->head].len = len;
            list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
            kill_fasync(&list->fasync, SIGIO, POLL_IN);
      }

      wake_up_interruptible(&dev->wait);
}
EXPORT_SYMBOL_GPL(hidraw_report_event);

int hidraw_connect(struct hid_device *hid)
{
      int minor, result;
      struct hidraw *dev;

      /* TODO currently we accept any HID device. This should later
       * probably be fixed to accept only those devices which provide
       * non-input applications
       */

      dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
      if (!dev)
            return -ENOMEM;

      result = -EINVAL;

      spin_lock(&minors_lock);

      for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
            if (hidraw_table[minor])
                  continue;
            hidraw_table[minor] = dev;
            result = 0;
            break;
      }

      spin_unlock(&minors_lock);

      if (result) {
            kfree(dev);
            goto out;
      }

      dev->dev = device_create(hidraw_class, NULL, MKDEV(hidraw_major, minor),
                        "%s%d", "hidraw", minor);

      if (IS_ERR(dev->dev)) {
            spin_lock(&minors_lock);
            hidraw_table[minor] = NULL;
            spin_unlock(&minors_lock);
            result = PTR_ERR(dev->dev);
            kfree(dev);
            goto out;
      }

      init_waitqueue_head(&dev->wait);
      INIT_LIST_HEAD(&dev->list);

      dev->hid = hid;
      dev->minor = minor;

      dev->exist = 1;
      hid->hidraw = dev;

out:
      return result;

}
EXPORT_SYMBOL_GPL(hidraw_connect);

void hidraw_disconnect(struct hid_device *hid)
{
      struct hidraw *hidraw = hid->hidraw;

      hidraw->exist = 0;

      spin_lock(&minors_lock);
      hidraw_table[hidraw->minor] = NULL;
      spin_unlock(&minors_lock);

      device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));

      if (hidraw->open) {
            hid->hid_close(hid);
            wake_up_interruptible(&hidraw->wait);
      } else {
            kfree(hidraw);
      }
}
EXPORT_SYMBOL_GPL(hidraw_disconnect);

int __init hidraw_init(void)
{
      int result;
      dev_t dev_id;

      result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
                  HIDRAW_MAX_DEVICES, "hidraw");

      hidraw_major = MAJOR(dev_id);

      if (result < 0) {
            printk(KERN_WARNING "hidraw: can't get major number\n");
            result = 0;
            goto out;
      }

      hidraw_class = class_create(THIS_MODULE, "hidraw");
      if (IS_ERR(hidraw_class)) {
            result = PTR_ERR(hidraw_class);
            unregister_chrdev(hidraw_major, "hidraw");
            goto out;
      }

        cdev_init(&hidraw_cdev, &hidraw_ops);
        cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
out:
      return result;
}

void __exit hidraw_exit(void)
{
      dev_t dev_id = MKDEV(hidraw_major, 0);

      cdev_del(&hidraw_cdev);
      class_destroy(hidraw_class);
      unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);

}

Generated by  Doxygen 1.6.0   Back to index