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evdev.c

/*
 * Event char devices, giving access to raw input device events.
 *
 * Copyright (c) 1999-2002 Vojtech Pavlik
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#define EVDEV_MINOR_BASE      64
#define EVDEV_MINORS          32
#define EVDEV_BUFFER_SIZE     64

#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/major.h>
#include <linux/device.h>
#include <linux/compat.h>

struct evdev {
      int exist;
      int open;
      int minor;
      char name[16];
      struct input_handle handle;
      wait_queue_head_t wait;
      struct evdev_client *grab;
      struct list_head client_list;
      spinlock_t client_lock; /* protects client_list */
      struct mutex mutex;
      struct device dev;
};

struct evdev_client {
      struct input_event buffer[EVDEV_BUFFER_SIZE];
      int head;
      int tail;
      spinlock_t buffer_lock; /* protects access to buffer, head and tail */
      struct fasync_struct *fasync;
      struct evdev *evdev;
      struct list_head node;
};

static struct evdev *evdev_table[EVDEV_MINORS];
static DEFINE_MUTEX(evdev_table_mutex);

static void evdev_pass_event(struct evdev_client *client,
                       struct input_event *event)
{
      /*
       * Interrupts are disabled, just acquire the lock
       */
      spin_lock(&client->buffer_lock);
      client->buffer[client->head++] = *event;
      client->head &= EVDEV_BUFFER_SIZE - 1;
      spin_unlock(&client->buffer_lock);

      kill_fasync(&client->fasync, SIGIO, POLL_IN);
}

/*
 * Pass incoming event to all connected clients.
 */
static void evdev_event(struct input_handle *handle,
                  unsigned int type, unsigned int code, int value)
{
      struct evdev *evdev = handle->private;
      struct evdev_client *client;
      struct input_event event;

      do_gettimeofday(&event.time);
      event.type = type;
      event.code = code;
      event.value = value;

      rcu_read_lock();

      client = rcu_dereference(evdev->grab);
      if (client)
            evdev_pass_event(client, &event);
      else
            list_for_each_entry_rcu(client, &evdev->client_list, node)
                  evdev_pass_event(client, &event);

      rcu_read_unlock();

      wake_up_interruptible(&evdev->wait);
}

static int evdev_fasync(int fd, struct file *file, int on)
{
      struct evdev_client *client = file->private_data;
      int retval;

      retval = fasync_helper(fd, file, on, &client->fasync);

      return retval < 0 ? retval : 0;
}

static int evdev_flush(struct file *file, fl_owner_t id)
{
      struct evdev_client *client = file->private_data;
      struct evdev *evdev = client->evdev;
      int retval;

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

      if (!evdev->exist)
            retval = -ENODEV;
      else
            retval = input_flush_device(&evdev->handle, file);

      mutex_unlock(&evdev->mutex);
      return retval;
}

static void evdev_free(struct device *dev)
{
      struct evdev *evdev = container_of(dev, struct evdev, dev);

      kfree(evdev);
}

/*
 * Grabs an event device (along with underlying input device).
 * This function is called with evdev->mutex taken.
 */
static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
{
      int error;

      if (evdev->grab)
            return -EBUSY;

      error = input_grab_device(&evdev->handle);
      if (error)
            return error;

      rcu_assign_pointer(evdev->grab, client);
      synchronize_rcu();

      return 0;
}

static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
{
      if (evdev->grab != client)
            return  -EINVAL;

      rcu_assign_pointer(evdev->grab, NULL);
      synchronize_rcu();
      input_release_device(&evdev->handle);

      return 0;
}

static void evdev_attach_client(struct evdev *evdev,
                        struct evdev_client *client)
{
      spin_lock(&evdev->client_lock);
      list_add_tail_rcu(&client->node, &evdev->client_list);
      spin_unlock(&evdev->client_lock);
      synchronize_rcu();
}

static void evdev_detach_client(struct evdev *evdev,
                        struct evdev_client *client)
{
      spin_lock(&evdev->client_lock);
      list_del_rcu(&client->node);
      spin_unlock(&evdev->client_lock);
      synchronize_rcu();
}

static int evdev_open_device(struct evdev *evdev)
{
      int retval;

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

      if (!evdev->exist)
            retval = -ENODEV;
      else if (!evdev->open++) {
            retval = input_open_device(&evdev->handle);
            if (retval)
                  evdev->open--;
      }

      mutex_unlock(&evdev->mutex);
      return retval;
}

static void evdev_close_device(struct evdev *evdev)
{
      mutex_lock(&evdev->mutex);

      if (evdev->exist && !--evdev->open)
            input_close_device(&evdev->handle);

      mutex_unlock(&evdev->mutex);
}

/*
 * Wake up users waiting for IO so they can disconnect from
 * dead device.
 */
static void evdev_hangup(struct evdev *evdev)
{
      struct evdev_client *client;

      spin_lock(&evdev->client_lock);
      list_for_each_entry(client, &evdev->client_list, node)
            kill_fasync(&client->fasync, SIGIO, POLL_HUP);
      spin_unlock(&evdev->client_lock);

      wake_up_interruptible(&evdev->wait);
}

static int evdev_release(struct inode *inode, struct file *file)
{
      struct evdev_client *client = file->private_data;
      struct evdev *evdev = client->evdev;

      mutex_lock(&evdev->mutex);
      if (evdev->grab == client)
            evdev_ungrab(evdev, client);
      mutex_unlock(&evdev->mutex);

      evdev_fasync(-1, file, 0);
      evdev_detach_client(evdev, client);
      kfree(client);

      evdev_close_device(evdev);
      put_device(&evdev->dev);

      return 0;
}

static int evdev_open(struct inode *inode, struct file *file)
{
      struct evdev *evdev;
      struct evdev_client *client;
      int i = iminor(inode) - EVDEV_MINOR_BASE;
      int error;

      if (i >= EVDEV_MINORS)
            return -ENODEV;

      error = mutex_lock_interruptible(&evdev_table_mutex);
      if (error)
            return error;
      evdev = evdev_table[i];
      if (evdev)
            get_device(&evdev->dev);
      mutex_unlock(&evdev_table_mutex);

      if (!evdev)
            return -ENODEV;

      client = kzalloc(sizeof(struct evdev_client), GFP_KERNEL);
      if (!client) {
            error = -ENOMEM;
            goto err_put_evdev;
      }

      spin_lock_init(&client->buffer_lock);
      client->evdev = evdev;
      evdev_attach_client(evdev, client);

      error = evdev_open_device(evdev);
      if (error)
            goto err_free_client;

      file->private_data = client;
      return 0;

 err_free_client:
      evdev_detach_client(evdev, client);
      kfree(client);
 err_put_evdev:
      put_device(&evdev->dev);
      return error;
}

#ifdef CONFIG_COMPAT

struct input_event_compat {
      struct compat_timeval time;
      __u16 type;
      __u16 code;
      __s32 value;
};

/* Note to the author of this code: did it ever occur to
   you why the ifdefs are needed? Think about it again. -AK */
#ifdef CONFIG_X86_64
#  define COMPAT_TEST is_compat_task()
#elif defined(CONFIG_IA64)
#  define COMPAT_TEST IS_IA32_PROCESS(task_pt_regs(current))
#elif defined(CONFIG_S390)
#  define COMPAT_TEST test_thread_flag(TIF_31BIT)
#elif defined(CONFIG_MIPS)
#  define COMPAT_TEST test_thread_flag(TIF_32BIT_ADDR)
#else
#  define COMPAT_TEST test_thread_flag(TIF_32BIT)
#endif

static inline size_t evdev_event_size(void)
{
      return COMPAT_TEST ?
            sizeof(struct input_event_compat) : sizeof(struct input_event);
}

static int evdev_event_from_user(const char __user *buffer,
                         struct input_event *event)
{
      if (COMPAT_TEST) {
            struct input_event_compat compat_event;

            if (copy_from_user(&compat_event, buffer,
                           sizeof(struct input_event_compat)))
                  return -EFAULT;

            event->time.tv_sec = compat_event.time.tv_sec;
            event->time.tv_usec = compat_event.time.tv_usec;
            event->type = compat_event.type;
            event->code = compat_event.code;
            event->value = compat_event.value;

      } else {
            if (copy_from_user(event, buffer, sizeof(struct input_event)))
                  return -EFAULT;
      }

      return 0;
}

static int evdev_event_to_user(char __user *buffer,
                        const struct input_event *event)
{
      if (COMPAT_TEST) {
            struct input_event_compat compat_event;

            compat_event.time.tv_sec = event->time.tv_sec;
            compat_event.time.tv_usec = event->time.tv_usec;
            compat_event.type = event->type;
            compat_event.code = event->code;
            compat_event.value = event->value;

            if (copy_to_user(buffer, &compat_event,
                         sizeof(struct input_event_compat)))
                  return -EFAULT;

      } else {
            if (copy_to_user(buffer, event, sizeof(struct input_event)))
                  return -EFAULT;
      }

      return 0;
}

#else

static inline size_t evdev_event_size(void)
{
      return sizeof(struct input_event);
}

static int evdev_event_from_user(const char __user *buffer,
                         struct input_event *event)
{
      if (copy_from_user(event, buffer, sizeof(struct input_event)))
            return -EFAULT;

      return 0;
}

static int evdev_event_to_user(char __user *buffer,
                        const struct input_event *event)
{
      if (copy_to_user(buffer, event, sizeof(struct input_event)))
            return -EFAULT;

      return 0;
}

#endif /* CONFIG_COMPAT */

static ssize_t evdev_write(struct file *file, const char __user *buffer,
                     size_t count, loff_t *ppos)
{
      struct evdev_client *client = file->private_data;
      struct evdev *evdev = client->evdev;
      struct input_event event;
      int retval;

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

      if (!evdev->exist) {
            retval = -ENODEV;
            goto out;
      }

      while (retval < count) {

            if (evdev_event_from_user(buffer + retval, &event)) {
                  retval = -EFAULT;
                  goto out;
            }

            input_inject_event(&evdev->handle,
                           event.type, event.code, event.value);
            retval += evdev_event_size();
      }

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

static int evdev_fetch_next_event(struct evdev_client *client,
                          struct input_event *event)
{
      int have_event;

      spin_lock_irq(&client->buffer_lock);

      have_event = client->head != client->tail;
      if (have_event) {
            *event = client->buffer[client->tail++];
            client->tail &= EVDEV_BUFFER_SIZE - 1;
      }

      spin_unlock_irq(&client->buffer_lock);

      return have_event;
}

static ssize_t evdev_read(struct file *file, char __user *buffer,
                    size_t count, loff_t *ppos)
{
      struct evdev_client *client = file->private_data;
      struct evdev *evdev = client->evdev;
      struct input_event event;
      int retval;

      if (count < evdev_event_size())
            return -EINVAL;

      if (client->head == client->tail && evdev->exist &&
          (file->f_flags & O_NONBLOCK))
            return -EAGAIN;

      retval = wait_event_interruptible(evdev->wait,
            client->head != client->tail || !evdev->exist);
      if (retval)
            return retval;

      if (!evdev->exist)
            return -ENODEV;

      while (retval + evdev_event_size() <= count &&
             evdev_fetch_next_event(client, &event)) {

            if (evdev_event_to_user(buffer + retval, &event))
                  return -EFAULT;

            retval += evdev_event_size();
      }

      return retval;
}

/* No kernel lock - fine */
static unsigned int evdev_poll(struct file *file, poll_table *wait)
{
      struct evdev_client *client = file->private_data;
      struct evdev *evdev = client->evdev;

      poll_wait(file, &evdev->wait, wait);
      return ((client->head == client->tail) ? 0 : (POLLIN | POLLRDNORM)) |
            (evdev->exist ? 0 : (POLLHUP | POLLERR));
}

#ifdef CONFIG_COMPAT

#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
#define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)

#ifdef __BIG_ENDIAN
static int bits_to_user(unsigned long *bits, unsigned int maxbit,
                  unsigned int maxlen, void __user *p, int compat)
{
      int len, i;

      if (compat) {
            len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
            if (len > maxlen)
                  len = maxlen;

            for (i = 0; i < len / sizeof(compat_long_t); i++)
                  if (copy_to_user((compat_long_t __user *) p + i,
                               (compat_long_t *) bits +
                                    i + 1 - ((i % 2) << 1),
                               sizeof(compat_long_t)))
                        return -EFAULT;
      } else {
            len = BITS_TO_LONGS(maxbit) * sizeof(long);
            if (len > maxlen)
                  len = maxlen;

            if (copy_to_user(p, bits, len))
                  return -EFAULT;
      }

      return len;
}
#else
static int bits_to_user(unsigned long *bits, unsigned int maxbit,
                  unsigned int maxlen, void __user *p, int compat)
{
      int len = compat ?
                  BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
                  BITS_TO_LONGS(maxbit) * sizeof(long);

      if (len > maxlen)
            len = maxlen;

      return copy_to_user(p, bits, len) ? -EFAULT : len;
}
#endif /* __BIG_ENDIAN */

#else

static int bits_to_user(unsigned long *bits, unsigned int maxbit,
                  unsigned int maxlen, void __user *p, int compat)
{
      int len = BITS_TO_LONGS(maxbit) * sizeof(long);

      if (len > maxlen)
            len = maxlen;

      return copy_to_user(p, bits, len) ? -EFAULT : len;
}

#endif /* CONFIG_COMPAT */

static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
{
      int len;

      if (!str)
            return -ENOENT;

      len = strlen(str) + 1;
      if (len > maxlen)
            len = maxlen;

      return copy_to_user(p, str, len) ? -EFAULT : len;
}

static long evdev_do_ioctl(struct file *file, unsigned int cmd,
                     void __user *p, int compat_mode)
{
      struct evdev_client *client = file->private_data;
      struct evdev *evdev = client->evdev;
      struct input_dev *dev = evdev->handle.dev;
      struct input_absinfo abs;
      struct ff_effect effect;
      int __user *ip = (int __user *)p;
      int i, t, u, v;
      int error;

      switch (cmd) {

      case EVIOCGVERSION:
            return put_user(EV_VERSION, ip);

      case EVIOCGID:
            if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
                  return -EFAULT;
            return 0;

      case EVIOCGREP:
            if (!test_bit(EV_REP, dev->evbit))
                  return -ENOSYS;
            if (put_user(dev->rep[REP_DELAY], ip))
                  return -EFAULT;
            if (put_user(dev->rep[REP_PERIOD], ip + 1))
                  return -EFAULT;
            return 0;

      case EVIOCSREP:
            if (!test_bit(EV_REP, dev->evbit))
                  return -ENOSYS;
            if (get_user(u, ip))
                  return -EFAULT;
            if (get_user(v, ip + 1))
                  return -EFAULT;

            input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
            input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);

            return 0;

      case EVIOCGKEYCODE:
            if (get_user(t, ip))
                  return -EFAULT;

            error = dev->getkeycode(dev, t, &v);
            if (error)
                  return error;

            if (put_user(v, ip + 1))
                  return -EFAULT;

            return 0;

      case EVIOCSKEYCODE:
            if (get_user(t, ip) || get_user(v, ip + 1))
                  return -EFAULT;

            return dev->setkeycode(dev, t, v);

      case EVIOCSFF:
            if (copy_from_user(&effect, p, sizeof(effect)))
                  return -EFAULT;

            error = input_ff_upload(dev, &effect, file);

            if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
                  return -EFAULT;

            return error;

      case EVIOCRMFF:
            return input_ff_erase(dev, (int)(unsigned long) p, file);

      case EVIOCGEFFECTS:
            i = test_bit(EV_FF, dev->evbit) ?
                        dev->ff->max_effects : 0;
            if (put_user(i, ip))
                  return -EFAULT;
            return 0;

      case EVIOCGRAB:
            if (p)
                  return evdev_grab(evdev, client);
            else
                  return evdev_ungrab(evdev, client);

      default:

            if (_IOC_TYPE(cmd) != 'E')
                  return -EINVAL;

            if (_IOC_DIR(cmd) == _IOC_READ) {

                  if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) {

                        unsigned long *bits;
                        int len;

                        switch (_IOC_NR(cmd) & EV_MAX) {

                        case      0: bits = dev->evbit;  len = EV_MAX;  break;
                        case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
                        case EV_REL: bits = dev->relbit; len = REL_MAX; break;
                        case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
                        case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
                        case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
                        case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
                        case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
                        case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
                        default: return -EINVAL;
                  }
                        return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
                  }

                  if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))
                        return bits_to_user(dev->key, KEY_MAX, _IOC_SIZE(cmd),
                                        p, compat_mode);

                  if (_IOC_NR(cmd) == _IOC_NR(EVIOCGLED(0)))
                        return bits_to_user(dev->led, LED_MAX, _IOC_SIZE(cmd),
                                        p, compat_mode);

                  if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSND(0)))
                        return bits_to_user(dev->snd, SND_MAX, _IOC_SIZE(cmd),
                                        p, compat_mode);

                  if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSW(0)))
                        return bits_to_user(dev->sw, SW_MAX, _IOC_SIZE(cmd),
                                        p, compat_mode);

                  if (_IOC_NR(cmd) == _IOC_NR(EVIOCGNAME(0)))
                        return str_to_user(dev->name, _IOC_SIZE(cmd), p);

                  if (_IOC_NR(cmd) == _IOC_NR(EVIOCGPHYS(0)))
                        return str_to_user(dev->phys, _IOC_SIZE(cmd), p);

                  if (_IOC_NR(cmd) == _IOC_NR(EVIOCGUNIQ(0)))
                        return str_to_user(dev->uniq, _IOC_SIZE(cmd), p);

                  if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {

                        t = _IOC_NR(cmd) & ABS_MAX;

                        abs.value = dev->abs[t];
                        abs.minimum = dev->absmin[t];
                        abs.maximum = dev->absmax[t];
                        abs.fuzz = dev->absfuzz[t];
                        abs.flat = dev->absflat[t];

                        if (copy_to_user(p, &abs, sizeof(struct input_absinfo)))
                              return -EFAULT;

                        return 0;
                  }

            }

            if (_IOC_DIR(cmd) == _IOC_WRITE) {

                  if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {

                        t = _IOC_NR(cmd) & ABS_MAX;

                        if (copy_from_user(&abs, p,
                                    sizeof(struct input_absinfo)))
                              return -EFAULT;

                        /*
                         * Take event lock to ensure that we are not
                         * changing device parameters in the middle
                         * of event.
                         */
                        spin_lock_irq(&dev->event_lock);

                        dev->abs[t] = abs.value;
                        dev->absmin[t] = abs.minimum;
                        dev->absmax[t] = abs.maximum;
                        dev->absfuzz[t] = abs.fuzz;
                        dev->absflat[t] = abs.flat;

                        spin_unlock_irq(&dev->event_lock);

                        return 0;
                  }
            }
      }
      return -EINVAL;
}

static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
                        void __user *p, int compat_mode)
{
      struct evdev_client *client = file->private_data;
      struct evdev *evdev = client->evdev;
      int retval;

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

      if (!evdev->exist) {
            retval = -ENODEV;
            goto out;
      }

      retval = evdev_do_ioctl(file, cmd, p, compat_mode);

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

static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
      return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
}

#ifdef CONFIG_COMPAT
static long evdev_ioctl_compat(struct file *file,
                        unsigned int cmd, unsigned long arg)
{
      return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
}
#endif

static const struct file_operations evdev_fops = {
      .owner            = THIS_MODULE,
      .read       = evdev_read,
      .write            = evdev_write,
      .poll       = evdev_poll,
      .open       = evdev_open,
      .release    = evdev_release,
      .unlocked_ioctl   = evdev_ioctl,
#ifdef CONFIG_COMPAT
      .compat_ioctl     = evdev_ioctl_compat,
#endif
      .fasync           = evdev_fasync,
      .flush            = evdev_flush
};

static int evdev_install_chrdev(struct evdev *evdev)
{
      /*
       * No need to do any locking here as calls to connect and
       * disconnect are serialized by the input core
       */
      evdev_table[evdev->minor] = evdev;
      return 0;
}

static void evdev_remove_chrdev(struct evdev *evdev)
{
      /*
       * Lock evdev table to prevent race with evdev_open()
       */
      mutex_lock(&evdev_table_mutex);
      evdev_table[evdev->minor] = NULL;
      mutex_unlock(&evdev_table_mutex);
}

/*
 * Mark device non-existent. This disables writes, ioctls and
 * prevents new users from opening the device. Already posted
 * blocking reads will stay, however new ones will fail.
 */
static void evdev_mark_dead(struct evdev *evdev)
{
      mutex_lock(&evdev->mutex);
      evdev->exist = 0;
      mutex_unlock(&evdev->mutex);
}

static void evdev_cleanup(struct evdev *evdev)
{
      struct input_handle *handle = &evdev->handle;

      evdev_mark_dead(evdev);
      evdev_hangup(evdev);
      evdev_remove_chrdev(evdev);

      /* evdev is marked dead so no one else accesses evdev->open */
      if (evdev->open) {
            input_flush_device(handle, NULL);
            input_close_device(handle);
      }
}

/*
 * Create new evdev device. Note that input core serializes calls
 * to connect and disconnect so we don't need to lock evdev_table here.
 */
static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
                   const struct input_device_id *id)
{
      struct evdev *evdev;
      int minor;
      int error;

      for (minor = 0; minor < EVDEV_MINORS; minor++)
            if (!evdev_table[minor])
                  break;

      if (minor == EVDEV_MINORS) {
            printk(KERN_ERR "evdev: no more free evdev devices\n");
            return -ENFILE;
      }

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

      INIT_LIST_HEAD(&evdev->client_list);
      spin_lock_init(&evdev->client_lock);
      mutex_init(&evdev->mutex);
      init_waitqueue_head(&evdev->wait);

      snprintf(evdev->name, sizeof(evdev->name), "event%d", minor);
      evdev->exist = 1;
      evdev->minor = minor;

      evdev->handle.dev = dev;
      evdev->handle.name = evdev->name;
      evdev->handle.handler = handler;
      evdev->handle.private = evdev;

      strlcpy(evdev->dev.bus_id, evdev->name, sizeof(evdev->dev.bus_id));
      evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
      evdev->dev.class = &input_class;
      evdev->dev.parent = &dev->dev;
      evdev->dev.release = evdev_free;
      device_initialize(&evdev->dev);

      error = input_register_handle(&evdev->handle);
      if (error)
            goto err_free_evdev;

      error = evdev_install_chrdev(evdev);
      if (error)
            goto err_unregister_handle;

      error = device_add(&evdev->dev);
      if (error)
            goto err_cleanup_evdev;

      return 0;

 err_cleanup_evdev:
      evdev_cleanup(evdev);
 err_unregister_handle:
      input_unregister_handle(&evdev->handle);
 err_free_evdev:
      put_device(&evdev->dev);
      return error;
}

static void evdev_disconnect(struct input_handle *handle)
{
      struct evdev *evdev = handle->private;

      device_del(&evdev->dev);
      evdev_cleanup(evdev);
      input_unregister_handle(handle);
      put_device(&evdev->dev);
}

static const struct input_device_id evdev_ids[] = {
      { .driver_info = 1 },   /* Matches all devices */
      { },              /* Terminating zero entry */
};

MODULE_DEVICE_TABLE(input, evdev_ids);

static struct input_handler evdev_handler = {
      .event            = evdev_event,
      .connect    = evdev_connect,
      .disconnect = evdev_disconnect,
      .fops       = &evdev_fops,
      .minor            = EVDEV_MINOR_BASE,
      .name       = "evdev",
      .id_table   = evdev_ids,
};

static int __init evdev_init(void)
{
      return input_register_handler(&evdev_handler);
}

static void __exit evdev_exit(void)
{
      input_unregister_handler(&evdev_handler);
}

module_init(evdev_init);
module_exit(evdev_exit);

MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("Input driver event char devices");
MODULE_LICENSE("GPL");

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