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uinput.c

/*
 *  User level driver support for input subsystem
 *
 * Heavily based on evdev.c by Vojtech Pavlik
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
 *
 * Changes/Revisions:
 *    0.3   09/04/2006 (Anssi Hannula <anssi.hannula@gmail.com>)
 *          - updated ff support for the changes in kernel interface
 *          - added MODULE_VERSION
 *    0.2   16/10/2004 (Micah Dowty <micah@navi.cx>)
 *          - added force feedback support
 *              - added UI_SET_PHYS
 *    0.1   20/06/2002
 *          - first public version
 */
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/uinput.h>

static int uinput_dev_event(struct input_dev *dev, unsigned int type, unsigned int code, int value)
{
      struct uinput_device    *udev = input_get_drvdata(dev);

      udev->buff[udev->head].type = type;
      udev->buff[udev->head].code = code;
      udev->buff[udev->head].value = value;
      do_gettimeofday(&udev->buff[udev->head].time);
      udev->head = (udev->head + 1) % UINPUT_BUFFER_SIZE;

      wake_up_interruptible(&udev->waitq);

      return 0;
}

static int uinput_request_alloc_id(struct uinput_device *udev, struct uinput_request *request)
{
      /* Atomically allocate an ID for the given request. Returns 0 on success. */
      int id;
      int err = -1;

      spin_lock(&udev->requests_lock);

      for (id = 0; id < UINPUT_NUM_REQUESTS; id++)
            if (!udev->requests[id]) {
                  request->id = id;
                  udev->requests[id] = request;
                  err = 0;
                  break;
            }

      spin_unlock(&udev->requests_lock);
      return err;
}

static struct uinput_request* uinput_request_find(struct uinput_device *udev, int id)
{
      /* Find an input request, by ID. Returns NULL if the ID isn't valid. */
      if (id >= UINPUT_NUM_REQUESTS || id < 0)
            return NULL;
      return udev->requests[id];
}

static inline int uinput_request_reserve_slot(struct uinput_device *udev, struct uinput_request *request)
{
      /* Allocate slot. If none are available right away, wait. */
      return wait_event_interruptible(udev->requests_waitq,
                              !uinput_request_alloc_id(udev, request));
}

static void uinput_request_done(struct uinput_device *udev, struct uinput_request *request)
{
      /* Mark slot as available */
      udev->requests[request->id] = NULL;
      wake_up(&udev->requests_waitq);

      complete(&request->done);
}

static int uinput_request_submit(struct input_dev *dev, struct uinput_request *request)
{
      /* Tell our userspace app about this new request by queueing an input event */
      uinput_dev_event(dev, EV_UINPUT, request->code, request->id);

      /* Wait for the request to complete */
      wait_for_completion(&request->done);
      return request->retval;
}

static void uinput_dev_set_gain(struct input_dev *dev, u16 gain)
{
      uinput_dev_event(dev, EV_FF, FF_GAIN, gain);
}

static void uinput_dev_set_autocenter(struct input_dev *dev, u16 magnitude)
{
      uinput_dev_event(dev, EV_FF, FF_AUTOCENTER, magnitude);
}

static int uinput_dev_playback(struct input_dev *dev, int effect_id, int value)
{
      return uinput_dev_event(dev, EV_FF, effect_id, value);
}

static int uinput_dev_upload_effect(struct input_dev *dev, struct ff_effect *effect, struct ff_effect *old)
{
      struct uinput_request request;
      int retval;

      request.id = -1;
      init_completion(&request.done);
      request.code = UI_FF_UPLOAD;
      request.u.upload.effect = effect;
      request.u.upload.old = old;

      retval = uinput_request_reserve_slot(input_get_drvdata(dev), &request);
      if (!retval)
            retval = uinput_request_submit(dev, &request);

      return retval;
}

static int uinput_dev_erase_effect(struct input_dev *dev, int effect_id)
{
      struct uinput_request request;
      int retval;

      if (!test_bit(EV_FF, dev->evbit))
            return -ENOSYS;

      request.id = -1;
      init_completion(&request.done);
      request.code = UI_FF_ERASE;
      request.u.effect_id = effect_id;

      retval = uinput_request_reserve_slot(input_get_drvdata(dev), &request);
      if (!retval)
            retval = uinput_request_submit(dev, &request);

      return retval;
}

static void uinput_destroy_device(struct uinput_device *udev)
{
      const char *name, *phys;

      if (udev->dev) {
            name = udev->dev->name;
            phys = udev->dev->phys;
            if (udev->state == UIST_CREATED)
                  input_unregister_device(udev->dev);
            else
                  input_free_device(udev->dev);
            kfree(name);
            kfree(phys);
            udev->dev = NULL;
      }

      udev->state = UIST_NEW_DEVICE;
}

static int uinput_create_device(struct uinput_device *udev)
{
      struct input_dev *dev = udev->dev;
      int error;

      if (udev->state != UIST_SETUP_COMPLETE) {
            printk(KERN_DEBUG "%s: write device info first\n", UINPUT_NAME);
            return -EINVAL;
      }

      if (udev->ff_effects_max) {
            error = input_ff_create(dev, udev->ff_effects_max);
            if (error)
                  goto fail1;

            dev->ff->upload = uinput_dev_upload_effect;
            dev->ff->erase = uinput_dev_erase_effect;
            dev->ff->playback = uinput_dev_playback;
            dev->ff->set_gain = uinput_dev_set_gain;
            dev->ff->set_autocenter = uinput_dev_set_autocenter;
      }

      error = input_register_device(udev->dev);
      if (error)
            goto fail2;

      udev->state = UIST_CREATED;

      return 0;

 fail2:     input_ff_destroy(dev);
 fail1: uinput_destroy_device(udev);
      return error;
}

static int uinput_open(struct inode *inode, struct file *file)
{
      struct uinput_device *newdev;

      newdev = kzalloc(sizeof(struct uinput_device), GFP_KERNEL);
      if (!newdev)
            return -ENOMEM;

      mutex_init(&newdev->mutex);
      spin_lock_init(&newdev->requests_lock);
      init_waitqueue_head(&newdev->requests_waitq);
      init_waitqueue_head(&newdev->waitq);
      newdev->state = UIST_NEW_DEVICE;

      file->private_data = newdev;

      return 0;
}

static int uinput_validate_absbits(struct input_dev *dev)
{
      unsigned int cnt;
      int retval = 0;

      for (cnt = 0; cnt < ABS_MAX + 1; cnt++) {
            if (!test_bit(cnt, dev->absbit))
                  continue;

            if ((dev->absmax[cnt] <= dev->absmin[cnt])) {
                  printk(KERN_DEBUG
                        "%s: invalid abs[%02x] min:%d max:%d\n",
                        UINPUT_NAME, cnt,
                        dev->absmin[cnt], dev->absmax[cnt]);
                  retval = -EINVAL;
                  break;
            }

            if (dev->absflat[cnt] > (dev->absmax[cnt] - dev->absmin[cnt])) {
                  printk(KERN_DEBUG
                        "%s: absflat[%02x] out of range: %d "
                        "(min:%d/max:%d)\n",
                        UINPUT_NAME, cnt, dev->absflat[cnt],
                        dev->absmin[cnt], dev->absmax[cnt]);
                  retval = -EINVAL;
                  break;
            }
      }
      return retval;
}

static int uinput_allocate_device(struct uinput_device *udev)
{
      udev->dev = input_allocate_device();
      if (!udev->dev)
            return -ENOMEM;

      udev->dev->event = uinput_dev_event;
      input_set_drvdata(udev->dev, udev);

      return 0;
}

static int uinput_setup_device(struct uinput_device *udev, const char __user *buffer, size_t count)
{
      struct uinput_user_dev  *user_dev;
      struct input_dev  *dev;
      char              *name;
      int               size;
      int               retval;

      if (count != sizeof(struct uinput_user_dev))
            return -EINVAL;

      if (!udev->dev) {
            retval = uinput_allocate_device(udev);
            if (retval)
                  return retval;
      }

      dev = udev->dev;

      user_dev = kmalloc(sizeof(struct uinput_user_dev), GFP_KERNEL);
      if (!user_dev)
            return -ENOMEM;

      if (copy_from_user(user_dev, buffer, sizeof(struct uinput_user_dev))) {
            retval = -EFAULT;
            goto exit;
      }

      udev->ff_effects_max = user_dev->ff_effects_max;

      size = strnlen(user_dev->name, UINPUT_MAX_NAME_SIZE) + 1;
      if (!size) {
            retval = -EINVAL;
            goto exit;
      }

      kfree(dev->name);
      dev->name = name = kmalloc(size, GFP_KERNEL);
      if (!name) {
            retval = -ENOMEM;
            goto exit;
      }
      strlcpy(name, user_dev->name, size);

      dev->id.bustype   = user_dev->id.bustype;
      dev->id.vendor    = user_dev->id.vendor;
      dev->id.product   = user_dev->id.product;
      dev->id.version   = user_dev->id.version;

      size = sizeof(int) * (ABS_MAX + 1);
      memcpy(dev->absmax, user_dev->absmax, size);
      memcpy(dev->absmin, user_dev->absmin, size);
      memcpy(dev->absfuzz, user_dev->absfuzz, size);
      memcpy(dev->absflat, user_dev->absflat, size);

      /* check if absmin/absmax/absfuzz/absflat are filled as
       * told in Documentation/input/input-programming.txt */
      if (test_bit(EV_ABS, dev->evbit)) {
            retval = uinput_validate_absbits(dev);
            if (retval < 0)
                  goto exit;
      }

      udev->state = UIST_SETUP_COMPLETE;
      retval = count;

 exit:
      kfree(user_dev);
      return retval;
}

static inline ssize_t uinput_inject_event(struct uinput_device *udev, const char __user *buffer, size_t count)
{
      struct input_event ev;

      if (count != sizeof(struct input_event))
            return -EINVAL;

      if (copy_from_user(&ev, buffer, sizeof(struct input_event)))
            return -EFAULT;

      input_event(udev->dev, ev.type, ev.code, ev.value);

      return sizeof(struct input_event);
}

static ssize_t uinput_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
      struct uinput_device *udev = file->private_data;
      int retval;

      retval = mutex_lock_interruptible(&udev->mutex);
      if (retval)
            return retval;

      retval = udev->state == UIST_CREATED ?
                  uinput_inject_event(udev, buffer, count) :
                  uinput_setup_device(udev, buffer, count);

      mutex_unlock(&udev->mutex);

      return retval;
}

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 + sizeof(struct input_event) <= count) {
            if (copy_to_user(buffer + retval, &udev->buff[udev->tail], sizeof(struct input_event))) {
                  retval = -EFAULT;
                  goto out;
            }
            udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE;
            retval += sizeof(struct input_event);
      }

 out:
      mutex_unlock(&udev->mutex);

      return retval;
}

static unsigned int uinput_poll(struct file *file, poll_table *wait)
{
      struct uinput_device *udev = file->private_data;

      poll_wait(file, &udev->waitq, wait);

      if (udev->head != udev->tail)
            return POLLIN | POLLRDNORM;

      return 0;
}

static int uinput_release(struct inode *inode, struct file *file)
{
      struct uinput_device *udev = file->private_data;

      uinput_destroy_device(udev);
      kfree(udev);

      return 0;
}

#define uinput_set_bit(_arg, _bit, _max)        \
({                                        \
      int __ret = 0;                            \
      if (udev->state == UIST_CREATED)          \
            __ret =  -EINVAL;             \
      else if ((_arg) > (_max))                 \
            __ret = -EINVAL;              \
      else set_bit((_arg), udev->dev->_bit);          \
      __ret;                                    \
})

static long uinput_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
      int               retval;
      struct uinput_device    *udev;
      void __user             *p = (void __user *)arg;
      struct uinput_ff_upload ff_up;
      struct uinput_ff_erase  ff_erase;
      struct uinput_request   *req;
      int                     length;
      char              *phys;

      udev = file->private_data;

      retval = mutex_lock_interruptible(&udev->mutex);
      if (retval)
            return retval;

      if (!udev->dev) {
            retval = uinput_allocate_device(udev);
            if (retval)
                  goto out;
      }

      switch (cmd) {
            case UI_DEV_CREATE:
                  retval = uinput_create_device(udev);
                  break;

            case UI_DEV_DESTROY:
                  uinput_destroy_device(udev);
                  break;

            case UI_SET_EVBIT:
                  retval = uinput_set_bit(arg, evbit, EV_MAX);
                  break;

            case UI_SET_KEYBIT:
                  retval = uinput_set_bit(arg, keybit, KEY_MAX);
                  break;

            case UI_SET_RELBIT:
                  retval = uinput_set_bit(arg, relbit, REL_MAX);
                  break;

            case UI_SET_ABSBIT:
                  retval = uinput_set_bit(arg, absbit, ABS_MAX);
                  break;

            case UI_SET_MSCBIT:
                  retval = uinput_set_bit(arg, mscbit, MSC_MAX);
                  break;

            case UI_SET_LEDBIT:
                  retval = uinput_set_bit(arg, ledbit, LED_MAX);
                  break;

            case UI_SET_SNDBIT:
                  retval = uinput_set_bit(arg, sndbit, SND_MAX);
                  break;

            case UI_SET_FFBIT:
                  retval = uinput_set_bit(arg, ffbit, FF_MAX);
                  break;

            case UI_SET_SWBIT:
                  retval = uinput_set_bit(arg, swbit, SW_MAX);
                  break;

            case UI_SET_PHYS:
                  if (udev->state == UIST_CREATED) {
                        retval = -EINVAL;
                        goto out;
                  }
                  length = strnlen_user(p, 1024);
                  if (length <= 0) {
                        retval = -EFAULT;
                        break;
                  }
                  kfree(udev->dev->phys);
                  udev->dev->phys = phys = kmalloc(length, GFP_KERNEL);
                  if (!phys) {
                        retval = -ENOMEM;
                        break;
                  }
                  if (copy_from_user(phys, p, length)) {
                        udev->dev->phys = NULL;
                        kfree(phys);
                        retval = -EFAULT;
                        break;
                  }
                  phys[length - 1] = '\0';
                  break;

            case UI_BEGIN_FF_UPLOAD:
                  if (copy_from_user(&ff_up, p, sizeof(ff_up))) {
                        retval = -EFAULT;
                        break;
                  }
                  req = uinput_request_find(udev, ff_up.request_id);
                  if (!(req && req->code == UI_FF_UPLOAD && req->u.upload.effect)) {
                        retval = -EINVAL;
                        break;
                  }
                  ff_up.retval = 0;
                  memcpy(&ff_up.effect, req->u.upload.effect, sizeof(struct ff_effect));
                  if (req->u.upload.old)
                        memcpy(&ff_up.old, req->u.upload.old, sizeof(struct ff_effect));
                  else
                        memset(&ff_up.old, 0, sizeof(struct ff_effect));

                  if (copy_to_user(p, &ff_up, sizeof(ff_up))) {
                        retval = -EFAULT;
                        break;
                  }
                  break;

            case UI_BEGIN_FF_ERASE:
                  if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
                        retval = -EFAULT;
                        break;
                  }
                  req = uinput_request_find(udev, ff_erase.request_id);
                  if (!(req && req->code == UI_FF_ERASE)) {
                        retval = -EINVAL;
                        break;
                  }
                  ff_erase.retval = 0;
                  ff_erase.effect_id = req->u.effect_id;
                  if (copy_to_user(p, &ff_erase, sizeof(ff_erase))) {
                        retval = -EFAULT;
                        break;
                  }
                  break;

            case UI_END_FF_UPLOAD:
                  if (copy_from_user(&ff_up, p, sizeof(ff_up))) {
                        retval = -EFAULT;
                        break;
                  }
                  req = uinput_request_find(udev, ff_up.request_id);
                  if (!(req && req->code == UI_FF_UPLOAD && req->u.upload.effect)) {
                        retval = -EINVAL;
                        break;
                  }
                  req->retval = ff_up.retval;
                  uinput_request_done(udev, req);
                  break;

            case UI_END_FF_ERASE:
                  if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
                        retval = -EFAULT;
                        break;
                  }
                  req = uinput_request_find(udev, ff_erase.request_id);
                  if (!(req && req->code == UI_FF_ERASE)) {
                        retval = -EINVAL;
                        break;
                  }
                  req->retval = ff_erase.retval;
                  uinput_request_done(udev, req);
                  break;

            default:
                  retval = -EINVAL;
      }

 out:
      mutex_unlock(&udev->mutex);
      return retval;
}

static const struct file_operations uinput_fops = {
      .owner            = THIS_MODULE,
      .open       = uinput_open,
      .release    = uinput_release,
      .read       = uinput_read,
      .write            = uinput_write,
      .poll       = uinput_poll,
      .unlocked_ioctl   = uinput_ioctl,
};

static struct miscdevice uinput_misc = {
      .fops       = &uinput_fops,
      .minor            = UINPUT_MINOR,
      .name       = UINPUT_NAME,
};

static int __init uinput_init(void)
{
      return misc_register(&uinput_misc);
}

static void __exit uinput_exit(void)
{
      misc_deregister(&uinput_misc);
}

MODULE_AUTHOR("Aristeu Sergio Rozanski Filho");
MODULE_DESCRIPTION("User level driver support for input subsystem");
MODULE_LICENSE("GPL");
MODULE_VERSION("0.3");

module_init(uinput_init);
module_exit(uinput_exit);


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