/*
   * 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/smp_lock.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_list *grab;
  	struct list_head list;
  };
  
  struct evdev_list {
  	struct input_event buffer[EVDEV_BUFFER_SIZE];
  	int head;
  	int tail;
  	struct fasync_struct *fasync;
  	struct evdev *evdev;
  	struct list_head node;
  };
  
  static struct evdev *evdev_table[EVDEV_MINORS];
  
  static void evdev_event(struct input_handle *handle, unsigned int type, unsigned int code, int value)
  {
  	struct evdev *evdev = handle->private;
  	struct evdev_list *list;
  
  	if (evdev->grab) {
  		list = evdev->grab;
  
  		do_gettimeofday(&list->buffer[list->head].time);
  		list->buffer[list->head].type = type;
  		list->buffer[list->head].code = code;
  		list->buffer[list->head].value = value;
  		list->head = (list->head + 1) & (EVDEV_BUFFER_SIZE - 1);
  
  		kill_fasync(&list->fasync, SIGIO, POLL_IN);
  	} else
  		list_for_each_entry(list, &evdev->list, node) {
  
  			do_gettimeofday(&list->buffer[list->head].time);
  			list->buffer[list->head].type = type;
  			list->buffer[list->head].code = code;
  			list->buffer[list->head].value = value;
  			list->head = (list->head + 1) & (EVDEV_BUFFER_SIZE - 1);
  
  			kill_fasync(&list->fasync, SIGIO, POLL_IN);
  		}
  
  	wake_up_interruptible(&evdev->wait);
  }
  
  static int evdev_fasync(int fd, struct file *file, int on)
  {
  	int retval;
  	struct evdev_list *list = file->private_data;

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

  	return retval < 0 ? retval : 0;
  }

  static int evdev_flush(struct file *file, fl_owner_t id)

  {
  	struct evdev_list *list = file->private_data;

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

  	return input_flush_device(&list->evdev->handle, file);
  }
  
  static void evdev_free(struct evdev *evdev)
  {
  	evdev_table[evdev->minor] = NULL;
  	kfree(evdev);
  }
  
  static int evdev_release(struct inode * inode, struct file * file)
  {
  	struct evdev_list *list = file->private_data;
  
  	if (list->evdev->grab == list) {
  		input_release_device(&list->evdev->handle);
  		list->evdev->grab = NULL;
  	}
  
  	evdev_fasync(-1, file, 0);
  	list_del(&list->node);
  
  	if (!--list->evdev->open) {
  		if (list->evdev->exist)
  			input_close_device(&list->evdev->handle);
  		else
  			evdev_free(list->evdev);
  	}
  
  	kfree(list);
  	return 0;
  }
  
  static int evdev_open(struct inode * inode, struct file * file)
  {
  	struct evdev_list *list;
  	int i = iminor(inode) - EVDEV_MINOR_BASE;

  
  	if (i >= EVDEV_MINORS || !evdev_table[i] || !evdev_table[i]->exist)
  		return -ENODEV;

  	if (!(list = kzalloc(sizeof(struct evdev_list), GFP_KERNEL)))

  		return -ENOMEM;

  
  	list->evdev = evdev_table[i];
  	list_add_tail(&list->node, &evdev_table[i]->list);
  	file->private_data = list;
  
  	if (!list->evdev->open++)
  		if (list->evdev->exist)
  			input_open_device(&list->evdev->handle);
  
  	return 0;
  }

  #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 (current->thread.mflags & MF_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_list *list = file->private_data;
  	struct input_event event;
  	int retval = 0;

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

  	while (retval < count) {
  
  		if (evdev_event_from_user(buffer + retval, &event))
  			return -EFAULT;

  		input_inject_event(&list->evdev->handle, event.type, event.code, event.value);

  		retval += evdev_event_size();

  	}
  
  	return retval;
  }

  static ssize_t evdev_read(struct file * file, char __user * buffer, size_t count, loff_t *ppos)
  {
  	struct evdev_list *list = file->private_data;
  	int retval;

  	if (count < evdev_event_size())

  		return -EINVAL;
  
  	if (list->head == list->tail && list->evdev->exist && (file->f_flags & O_NONBLOCK))
  		return -EAGAIN;
  
  	retval = wait_event_interruptible(list->evdev->wait,
  		list->head != list->tail || (!list->evdev->exist));
  
  	if (retval)
  		return retval;
  
  	if (!list->evdev->exist)
  		return -ENODEV;

  	while (list->head != list->tail && retval + evdev_event_size() <= count) {
  
  		struct input_event *event = (struct input_event *) list->buffer + list->tail;
  
  		if (evdev_event_to_user(buffer + retval, event))
  			return -EFAULT;

  		list->tail = (list->tail + 1) & (EVDEV_BUFFER_SIZE - 1);

  		retval += evdev_event_size();

  	}
  
  	return retval;
  }
  
  /* No kernel lock - fine */
  static unsigned int evdev_poll(struct file *file, poll_table *wait)
  {
  	struct evdev_list *list = file->private_data;

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

  #ifdef CONFIG_COMPAT
  
  #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
  #define NBITS_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 = NBITS_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 = NBITS(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 ?
  			NBITS_COMPAT(maxbit) * sizeof(compat_long_t) :
  			NBITS(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 = NBITS(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_ioctl_handler(struct file *file, unsigned int cmd,
  				void __user *p, int compat_mode)

  {
  	struct evdev_list *list = file->private_data;
  	struct evdev *evdev = list->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;

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

  
  	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) {

  				if (evdev->grab)
  					return -EBUSY;
  				if (input_grab_device(&evdev->handle))
  					return -EBUSY;
  				evdev->grab = list;
  				return 0;
  			} else {
  				if (evdev->grab != list)
  					return -EINVAL;
  				input_release_device(&evdev->handle);
  				evdev->grab = NULL;
  				return 0;
  			}
  
  		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))) {
  
  					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))) {

  					int 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))) {

  					int t = _IOC_NR(cmd) & ABS_MAX;
  
  					if (copy_from_user(&abs, p, sizeof(struct input_absinfo)))
  						return -EFAULT;

  					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;

  					return 0;
  				}

  			}

  	}
  	return -EINVAL;
  }

  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_connect(struct input_handler *handler, struct input_dev *dev,
  			 const struct input_device_id *id)

  {
  	struct evdev *evdev;

  	struct class_device *cdev;

  	dev_t devt;

  	int minor;

  	int error;

  
  	for (minor = 0; minor < EVDEV_MINORS && evdev_table[minor]; minor++);
  	if (minor == EVDEV_MINORS) {
  		printk(KERN_ERR "evdev: no more free evdev devices
  ");

  		return -ENFILE;

  	}

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

  
  	INIT_LIST_HEAD(&evdev->list);
  	init_waitqueue_head(&evdev->wait);
  
  	evdev->exist = 1;
  	evdev->minor = minor;
  	evdev->handle.dev = dev;
  	evdev->handle.name = evdev->name;
  	evdev->handle.handler = handler;
  	evdev->handle.private = evdev;
  	sprintf(evdev->name, "event%d", minor);
  
  	evdev_table[minor] = evdev;

  	devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor),
  
  	cdev = class_device_create(&input_class, &dev->cdev, devt,
  				   dev->cdev.dev, evdev->name);
  	if (IS_ERR(cdev)) {
  		error = PTR_ERR(cdev);
  		goto err_free_evdev;
  	}

  
  	/* temporary symlink to keep userspace happy */

  	error = sysfs_create_link(&input_class.subsys.kset.kobj,
  				  &cdev->kobj, evdev->name);
  	if (error)
  		goto err_cdev_destroy;
  
  	error = input_register_handle(&evdev->handle);
  	if (error)
  		goto err_remove_link;

  	return 0;
  
   err_remove_link:
  	sysfs_remove_link(&input_class.subsys.kset.kobj, evdev->name);
   err_cdev_destroy:
  	class_device_destroy(&input_class, devt);
   err_free_evdev:
  	kfree(evdev);
  	evdev_table[minor] = NULL;
  	return error;

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

  	input_unregister_handle(handle);

  	sysfs_remove_link(&input_class.subsys.kset.kobj, evdev->name);

  	class_device_destroy(&input_class,

  			MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + evdev->minor));

  	evdev->exist = 0;
  
  	if (evdev->open) {

  		input_flush_device(handle, NULL);

  		input_close_device(handle);
  		wake_up_interruptible(&evdev->wait);
  		list_for_each_entry(list, &evdev->list, node)
  			kill_fasync(&list->fasync, SIGIO, POLL_HUP);
  	} else
  		evdev_free(evdev);
  }

  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");