xref: /openbmc/linux/drivers/input/evdev.c (revision 1fa6ac37)
1 /*
2  * Event char devices, giving access to raw input device events.
3  *
4  * Copyright (c) 1999-2002 Vojtech Pavlik
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License version 2 as published by
8  * the Free Software Foundation.
9  */
10 
11 #define EVDEV_MINOR_BASE	64
12 #define EVDEV_MINORS		32
13 #define EVDEV_BUFFER_SIZE	64
14 
15 #include <linux/poll.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/input.h>
21 #include <linux/major.h>
22 #include <linux/device.h>
23 #include "input-compat.h"
24 
25 struct evdev {
26 	int exist;
27 	int open;
28 	int minor;
29 	struct input_handle handle;
30 	wait_queue_head_t wait;
31 	struct evdev_client *grab;
32 	struct list_head client_list;
33 	spinlock_t client_lock; /* protects client_list */
34 	struct mutex mutex;
35 	struct device dev;
36 };
37 
38 struct evdev_client {
39 	struct input_event buffer[EVDEV_BUFFER_SIZE];
40 	int head;
41 	int tail;
42 	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
43 	struct fasync_struct *fasync;
44 	struct evdev *evdev;
45 	struct list_head node;
46 };
47 
48 static struct evdev *evdev_table[EVDEV_MINORS];
49 static DEFINE_MUTEX(evdev_table_mutex);
50 
51 static void evdev_pass_event(struct evdev_client *client,
52 			     struct input_event *event)
53 {
54 	/*
55 	 * Interrupts are disabled, just acquire the lock
56 	 */
57 	spin_lock(&client->buffer_lock);
58 	client->buffer[client->head++] = *event;
59 	client->head &= EVDEV_BUFFER_SIZE - 1;
60 	spin_unlock(&client->buffer_lock);
61 
62 	if (event->type == EV_SYN)
63 		kill_fasync(&client->fasync, SIGIO, POLL_IN);
64 }
65 
66 /*
67  * Pass incoming event to all connected clients.
68  */
69 static void evdev_event(struct input_handle *handle,
70 			unsigned int type, unsigned int code, int value)
71 {
72 	struct evdev *evdev = handle->private;
73 	struct evdev_client *client;
74 	struct input_event event;
75 
76 	do_gettimeofday(&event.time);
77 	event.type = type;
78 	event.code = code;
79 	event.value = value;
80 
81 	rcu_read_lock();
82 
83 	client = rcu_dereference(evdev->grab);
84 	if (client)
85 		evdev_pass_event(client, &event);
86 	else
87 		list_for_each_entry_rcu(client, &evdev->client_list, node)
88 			evdev_pass_event(client, &event);
89 
90 	rcu_read_unlock();
91 
92 	wake_up_interruptible(&evdev->wait);
93 }
94 
95 static int evdev_fasync(int fd, struct file *file, int on)
96 {
97 	struct evdev_client *client = file->private_data;
98 
99 	return fasync_helper(fd, file, on, &client->fasync);
100 }
101 
102 static int evdev_flush(struct file *file, fl_owner_t id)
103 {
104 	struct evdev_client *client = file->private_data;
105 	struct evdev *evdev = client->evdev;
106 	int retval;
107 
108 	retval = mutex_lock_interruptible(&evdev->mutex);
109 	if (retval)
110 		return retval;
111 
112 	if (!evdev->exist)
113 		retval = -ENODEV;
114 	else
115 		retval = input_flush_device(&evdev->handle, file);
116 
117 	mutex_unlock(&evdev->mutex);
118 	return retval;
119 }
120 
121 static void evdev_free(struct device *dev)
122 {
123 	struct evdev *evdev = container_of(dev, struct evdev, dev);
124 
125 	input_put_device(evdev->handle.dev);
126 	kfree(evdev);
127 }
128 
129 /*
130  * Grabs an event device (along with underlying input device).
131  * This function is called with evdev->mutex taken.
132  */
133 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
134 {
135 	int error;
136 
137 	if (evdev->grab)
138 		return -EBUSY;
139 
140 	error = input_grab_device(&evdev->handle);
141 	if (error)
142 		return error;
143 
144 	rcu_assign_pointer(evdev->grab, client);
145 	synchronize_rcu();
146 
147 	return 0;
148 }
149 
150 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
151 {
152 	if (evdev->grab != client)
153 		return  -EINVAL;
154 
155 	rcu_assign_pointer(evdev->grab, NULL);
156 	synchronize_rcu();
157 	input_release_device(&evdev->handle);
158 
159 	return 0;
160 }
161 
162 static void evdev_attach_client(struct evdev *evdev,
163 				struct evdev_client *client)
164 {
165 	spin_lock(&evdev->client_lock);
166 	list_add_tail_rcu(&client->node, &evdev->client_list);
167 	spin_unlock(&evdev->client_lock);
168 	synchronize_rcu();
169 }
170 
171 static void evdev_detach_client(struct evdev *evdev,
172 				struct evdev_client *client)
173 {
174 	spin_lock(&evdev->client_lock);
175 	list_del_rcu(&client->node);
176 	spin_unlock(&evdev->client_lock);
177 	synchronize_rcu();
178 }
179 
180 static int evdev_open_device(struct evdev *evdev)
181 {
182 	int retval;
183 
184 	retval = mutex_lock_interruptible(&evdev->mutex);
185 	if (retval)
186 		return retval;
187 
188 	if (!evdev->exist)
189 		retval = -ENODEV;
190 	else if (!evdev->open++) {
191 		retval = input_open_device(&evdev->handle);
192 		if (retval)
193 			evdev->open--;
194 	}
195 
196 	mutex_unlock(&evdev->mutex);
197 	return retval;
198 }
199 
200 static void evdev_close_device(struct evdev *evdev)
201 {
202 	mutex_lock(&evdev->mutex);
203 
204 	if (evdev->exist && !--evdev->open)
205 		input_close_device(&evdev->handle);
206 
207 	mutex_unlock(&evdev->mutex);
208 }
209 
210 /*
211  * Wake up users waiting for IO so they can disconnect from
212  * dead device.
213  */
214 static void evdev_hangup(struct evdev *evdev)
215 {
216 	struct evdev_client *client;
217 
218 	spin_lock(&evdev->client_lock);
219 	list_for_each_entry(client, &evdev->client_list, node)
220 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
221 	spin_unlock(&evdev->client_lock);
222 
223 	wake_up_interruptible(&evdev->wait);
224 }
225 
226 static int evdev_release(struct inode *inode, struct file *file)
227 {
228 	struct evdev_client *client = file->private_data;
229 	struct evdev *evdev = client->evdev;
230 
231 	mutex_lock(&evdev->mutex);
232 	if (evdev->grab == client)
233 		evdev_ungrab(evdev, client);
234 	mutex_unlock(&evdev->mutex);
235 
236 	evdev_detach_client(evdev, client);
237 	kfree(client);
238 
239 	evdev_close_device(evdev);
240 	put_device(&evdev->dev);
241 
242 	return 0;
243 }
244 
245 static int evdev_open(struct inode *inode, struct file *file)
246 {
247 	struct evdev *evdev;
248 	struct evdev_client *client;
249 	int i = iminor(inode) - EVDEV_MINOR_BASE;
250 	int error;
251 
252 	if (i >= EVDEV_MINORS)
253 		return -ENODEV;
254 
255 	error = mutex_lock_interruptible(&evdev_table_mutex);
256 	if (error)
257 		return error;
258 	evdev = evdev_table[i];
259 	if (evdev)
260 		get_device(&evdev->dev);
261 	mutex_unlock(&evdev_table_mutex);
262 
263 	if (!evdev)
264 		return -ENODEV;
265 
266 	client = kzalloc(sizeof(struct evdev_client), GFP_KERNEL);
267 	if (!client) {
268 		error = -ENOMEM;
269 		goto err_put_evdev;
270 	}
271 
272 	spin_lock_init(&client->buffer_lock);
273 	client->evdev = evdev;
274 	evdev_attach_client(evdev, client);
275 
276 	error = evdev_open_device(evdev);
277 	if (error)
278 		goto err_free_client;
279 
280 	file->private_data = client;
281 	nonseekable_open(inode, file);
282 
283 	return 0;
284 
285  err_free_client:
286 	evdev_detach_client(evdev, client);
287 	kfree(client);
288  err_put_evdev:
289 	put_device(&evdev->dev);
290 	return error;
291 }
292 
293 static ssize_t evdev_write(struct file *file, const char __user *buffer,
294 			   size_t count, loff_t *ppos)
295 {
296 	struct evdev_client *client = file->private_data;
297 	struct evdev *evdev = client->evdev;
298 	struct input_event event;
299 	int retval;
300 
301 	retval = mutex_lock_interruptible(&evdev->mutex);
302 	if (retval)
303 		return retval;
304 
305 	if (!evdev->exist) {
306 		retval = -ENODEV;
307 		goto out;
308 	}
309 
310 	while (retval < count) {
311 
312 		if (input_event_from_user(buffer + retval, &event)) {
313 			retval = -EFAULT;
314 			goto out;
315 		}
316 
317 		input_inject_event(&evdev->handle,
318 				   event.type, event.code, event.value);
319 		retval += input_event_size();
320 	}
321 
322  out:
323 	mutex_unlock(&evdev->mutex);
324 	return retval;
325 }
326 
327 static int evdev_fetch_next_event(struct evdev_client *client,
328 				  struct input_event *event)
329 {
330 	int have_event;
331 
332 	spin_lock_irq(&client->buffer_lock);
333 
334 	have_event = client->head != client->tail;
335 	if (have_event) {
336 		*event = client->buffer[client->tail++];
337 		client->tail &= EVDEV_BUFFER_SIZE - 1;
338 	}
339 
340 	spin_unlock_irq(&client->buffer_lock);
341 
342 	return have_event;
343 }
344 
345 static ssize_t evdev_read(struct file *file, char __user *buffer,
346 			  size_t count, loff_t *ppos)
347 {
348 	struct evdev_client *client = file->private_data;
349 	struct evdev *evdev = client->evdev;
350 	struct input_event event;
351 	int retval;
352 
353 	if (count < input_event_size())
354 		return -EINVAL;
355 
356 	if (client->head == client->tail && evdev->exist &&
357 	    (file->f_flags & O_NONBLOCK))
358 		return -EAGAIN;
359 
360 	retval = wait_event_interruptible(evdev->wait,
361 		client->head != client->tail || !evdev->exist);
362 	if (retval)
363 		return retval;
364 
365 	if (!evdev->exist)
366 		return -ENODEV;
367 
368 	while (retval + input_event_size() <= count &&
369 	       evdev_fetch_next_event(client, &event)) {
370 
371 		if (input_event_to_user(buffer + retval, &event))
372 			return -EFAULT;
373 
374 		retval += input_event_size();
375 	}
376 
377 	return retval;
378 }
379 
380 /* No kernel lock - fine */
381 static unsigned int evdev_poll(struct file *file, poll_table *wait)
382 {
383 	struct evdev_client *client = file->private_data;
384 	struct evdev *evdev = client->evdev;
385 
386 	poll_wait(file, &evdev->wait, wait);
387 	return ((client->head == client->tail) ? 0 : (POLLIN | POLLRDNORM)) |
388 		(evdev->exist ? 0 : (POLLHUP | POLLERR));
389 }
390 
391 #ifdef CONFIG_COMPAT
392 
393 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
394 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
395 
396 #ifdef __BIG_ENDIAN
397 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
398 			unsigned int maxlen, void __user *p, int compat)
399 {
400 	int len, i;
401 
402 	if (compat) {
403 		len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
404 		if (len > maxlen)
405 			len = maxlen;
406 
407 		for (i = 0; i < len / sizeof(compat_long_t); i++)
408 			if (copy_to_user((compat_long_t __user *) p + i,
409 					 (compat_long_t *) bits +
410 						i + 1 - ((i % 2) << 1),
411 					 sizeof(compat_long_t)))
412 				return -EFAULT;
413 	} else {
414 		len = BITS_TO_LONGS(maxbit) * sizeof(long);
415 		if (len > maxlen)
416 			len = maxlen;
417 
418 		if (copy_to_user(p, bits, len))
419 			return -EFAULT;
420 	}
421 
422 	return len;
423 }
424 #else
425 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
426 			unsigned int maxlen, void __user *p, int compat)
427 {
428 	int len = compat ?
429 			BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
430 			BITS_TO_LONGS(maxbit) * sizeof(long);
431 
432 	if (len > maxlen)
433 		len = maxlen;
434 
435 	return copy_to_user(p, bits, len) ? -EFAULT : len;
436 }
437 #endif /* __BIG_ENDIAN */
438 
439 #else
440 
441 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
442 			unsigned int maxlen, void __user *p, int compat)
443 {
444 	int len = BITS_TO_LONGS(maxbit) * sizeof(long);
445 
446 	if (len > maxlen)
447 		len = maxlen;
448 
449 	return copy_to_user(p, bits, len) ? -EFAULT : len;
450 }
451 
452 #endif /* CONFIG_COMPAT */
453 
454 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
455 {
456 	int len;
457 
458 	if (!str)
459 		return -ENOENT;
460 
461 	len = strlen(str) + 1;
462 	if (len > maxlen)
463 		len = maxlen;
464 
465 	return copy_to_user(p, str, len) ? -EFAULT : len;
466 }
467 
468 #define OLD_KEY_MAX	0x1ff
469 static int handle_eviocgbit(struct input_dev *dev, unsigned int cmd, void __user *p, int compat_mode)
470 {
471 	static unsigned long keymax_warn_time;
472 	unsigned long *bits;
473 	int len;
474 
475 	switch (_IOC_NR(cmd) & EV_MAX) {
476 
477 	case      0: bits = dev->evbit;  len = EV_MAX;  break;
478 	case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
479 	case EV_REL: bits = dev->relbit; len = REL_MAX; break;
480 	case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
481 	case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
482 	case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
483 	case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
484 	case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
485 	case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
486 	default: return -EINVAL;
487 	}
488 
489 	/*
490 	 * Work around bugs in userspace programs that like to do
491 	 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
492 	 * should be in bytes, not in bits.
493 	 */
494 	if ((_IOC_NR(cmd) & EV_MAX) == EV_KEY && _IOC_SIZE(cmd) == OLD_KEY_MAX) {
495 		len = OLD_KEY_MAX;
496 		if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
497 			printk(KERN_WARNING
498 				"evdev.c(EVIOCGBIT): Suspicious buffer size %u, "
499 				"limiting output to %zu bytes. See "
500 				"http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
501 				OLD_KEY_MAX,
502 				BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
503 	}
504 
505 	return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
506 }
507 #undef OLD_KEY_MAX
508 
509 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
510 			   void __user *p, int compat_mode)
511 {
512 	struct evdev_client *client = file->private_data;
513 	struct evdev *evdev = client->evdev;
514 	struct input_dev *dev = evdev->handle.dev;
515 	struct input_absinfo abs;
516 	struct ff_effect effect;
517 	int __user *ip = (int __user *)p;
518 	unsigned int i, t, u, v;
519 	int error;
520 
521 	switch (cmd) {
522 
523 	case EVIOCGVERSION:
524 		return put_user(EV_VERSION, ip);
525 
526 	case EVIOCGID:
527 		if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
528 			return -EFAULT;
529 		return 0;
530 
531 	case EVIOCGREP:
532 		if (!test_bit(EV_REP, dev->evbit))
533 			return -ENOSYS;
534 		if (put_user(dev->rep[REP_DELAY], ip))
535 			return -EFAULT;
536 		if (put_user(dev->rep[REP_PERIOD], ip + 1))
537 			return -EFAULT;
538 		return 0;
539 
540 	case EVIOCSREP:
541 		if (!test_bit(EV_REP, dev->evbit))
542 			return -ENOSYS;
543 		if (get_user(u, ip))
544 			return -EFAULT;
545 		if (get_user(v, ip + 1))
546 			return -EFAULT;
547 
548 		input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
549 		input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
550 
551 		return 0;
552 
553 	case EVIOCGKEYCODE:
554 		if (get_user(t, ip))
555 			return -EFAULT;
556 
557 		error = input_get_keycode(dev, t, &v);
558 		if (error)
559 			return error;
560 
561 		if (put_user(v, ip + 1))
562 			return -EFAULT;
563 
564 		return 0;
565 
566 	case EVIOCSKEYCODE:
567 		if (get_user(t, ip) || get_user(v, ip + 1))
568 			return -EFAULT;
569 
570 		return input_set_keycode(dev, t, v);
571 
572 	case EVIOCRMFF:
573 		return input_ff_erase(dev, (int)(unsigned long) p, file);
574 
575 	case EVIOCGEFFECTS:
576 		i = test_bit(EV_FF, dev->evbit) ?
577 				dev->ff->max_effects : 0;
578 		if (put_user(i, ip))
579 			return -EFAULT;
580 		return 0;
581 
582 	case EVIOCGRAB:
583 		if (p)
584 			return evdev_grab(evdev, client);
585 		else
586 			return evdev_ungrab(evdev, client);
587 
588 	default:
589 
590 		if (_IOC_TYPE(cmd) != 'E')
591 			return -EINVAL;
592 
593 		if (_IOC_DIR(cmd) == _IOC_READ) {
594 
595 			if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
596 				return handle_eviocgbit(dev, cmd, p, compat_mode);
597 
598 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))
599 				return bits_to_user(dev->key, KEY_MAX, _IOC_SIZE(cmd),
600 						    p, compat_mode);
601 
602 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGLED(0)))
603 				return bits_to_user(dev->led, LED_MAX, _IOC_SIZE(cmd),
604 						    p, compat_mode);
605 
606 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSND(0)))
607 				return bits_to_user(dev->snd, SND_MAX, _IOC_SIZE(cmd),
608 						    p, compat_mode);
609 
610 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSW(0)))
611 				return bits_to_user(dev->sw, SW_MAX, _IOC_SIZE(cmd),
612 						    p, compat_mode);
613 
614 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGNAME(0)))
615 				return str_to_user(dev->name, _IOC_SIZE(cmd), p);
616 
617 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGPHYS(0)))
618 				return str_to_user(dev->phys, _IOC_SIZE(cmd), p);
619 
620 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGUNIQ(0)))
621 				return str_to_user(dev->uniq, _IOC_SIZE(cmd), p);
622 
623 			if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
624 
625 				t = _IOC_NR(cmd) & ABS_MAX;
626 
627 				abs.value = dev->abs[t];
628 				abs.minimum = dev->absmin[t];
629 				abs.maximum = dev->absmax[t];
630 				abs.fuzz = dev->absfuzz[t];
631 				abs.flat = dev->absflat[t];
632 				abs.resolution = dev->absres[t];
633 
634 				if (copy_to_user(p, &abs, min_t(size_t,
635 								_IOC_SIZE(cmd),
636 								sizeof(struct input_absinfo))))
637 					return -EFAULT;
638 
639 				return 0;
640 			}
641 
642 		}
643 
644 		if (_IOC_DIR(cmd) == _IOC_WRITE) {
645 
646 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCSFF)) {
647 
648 				if (input_ff_effect_from_user(p, _IOC_SIZE(cmd), &effect))
649 					return -EFAULT;
650 
651 				error = input_ff_upload(dev, &effect, file);
652 
653 				if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
654 					return -EFAULT;
655 
656 				return error;
657 			}
658 
659 			if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
660 
661 				t = _IOC_NR(cmd) & ABS_MAX;
662 
663 				if (copy_from_user(&abs, p, min_t(size_t,
664 								  _IOC_SIZE(cmd),
665 								  sizeof(struct input_absinfo))))
666 					return -EFAULT;
667 
668 				/*
669 				 * Take event lock to ensure that we are not
670 				 * changing device parameters in the middle
671 				 * of event.
672 				 */
673 				spin_lock_irq(&dev->event_lock);
674 
675 				dev->abs[t] = abs.value;
676 				dev->absmin[t] = abs.minimum;
677 				dev->absmax[t] = abs.maximum;
678 				dev->absfuzz[t] = abs.fuzz;
679 				dev->absflat[t] = abs.flat;
680 				dev->absres[t] = _IOC_SIZE(cmd) < sizeof(struct input_absinfo) ?
681 							0 : abs.resolution;
682 
683 				spin_unlock_irq(&dev->event_lock);
684 
685 				return 0;
686 			}
687 		}
688 	}
689 	return -EINVAL;
690 }
691 
692 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
693 				void __user *p, int compat_mode)
694 {
695 	struct evdev_client *client = file->private_data;
696 	struct evdev *evdev = client->evdev;
697 	int retval;
698 
699 	retval = mutex_lock_interruptible(&evdev->mutex);
700 	if (retval)
701 		return retval;
702 
703 	if (!evdev->exist) {
704 		retval = -ENODEV;
705 		goto out;
706 	}
707 
708 	retval = evdev_do_ioctl(file, cmd, p, compat_mode);
709 
710  out:
711 	mutex_unlock(&evdev->mutex);
712 	return retval;
713 }
714 
715 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
716 {
717 	return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
718 }
719 
720 #ifdef CONFIG_COMPAT
721 static long evdev_ioctl_compat(struct file *file,
722 				unsigned int cmd, unsigned long arg)
723 {
724 	return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
725 }
726 #endif
727 
728 static const struct file_operations evdev_fops = {
729 	.owner		= THIS_MODULE,
730 	.read		= evdev_read,
731 	.write		= evdev_write,
732 	.poll		= evdev_poll,
733 	.open		= evdev_open,
734 	.release	= evdev_release,
735 	.unlocked_ioctl	= evdev_ioctl,
736 #ifdef CONFIG_COMPAT
737 	.compat_ioctl	= evdev_ioctl_compat,
738 #endif
739 	.fasync		= evdev_fasync,
740 	.flush		= evdev_flush
741 };
742 
743 static int evdev_install_chrdev(struct evdev *evdev)
744 {
745 	/*
746 	 * No need to do any locking here as calls to connect and
747 	 * disconnect are serialized by the input core
748 	 */
749 	evdev_table[evdev->minor] = evdev;
750 	return 0;
751 }
752 
753 static void evdev_remove_chrdev(struct evdev *evdev)
754 {
755 	/*
756 	 * Lock evdev table to prevent race with evdev_open()
757 	 */
758 	mutex_lock(&evdev_table_mutex);
759 	evdev_table[evdev->minor] = NULL;
760 	mutex_unlock(&evdev_table_mutex);
761 }
762 
763 /*
764  * Mark device non-existent. This disables writes, ioctls and
765  * prevents new users from opening the device. Already posted
766  * blocking reads will stay, however new ones will fail.
767  */
768 static void evdev_mark_dead(struct evdev *evdev)
769 {
770 	mutex_lock(&evdev->mutex);
771 	evdev->exist = 0;
772 	mutex_unlock(&evdev->mutex);
773 }
774 
775 static void evdev_cleanup(struct evdev *evdev)
776 {
777 	struct input_handle *handle = &evdev->handle;
778 
779 	evdev_mark_dead(evdev);
780 	evdev_hangup(evdev);
781 	evdev_remove_chrdev(evdev);
782 
783 	/* evdev is marked dead so no one else accesses evdev->open */
784 	if (evdev->open) {
785 		input_flush_device(handle, NULL);
786 		input_close_device(handle);
787 	}
788 }
789 
790 /*
791  * Create new evdev device. Note that input core serializes calls
792  * to connect and disconnect so we don't need to lock evdev_table here.
793  */
794 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
795 			 const struct input_device_id *id)
796 {
797 	struct evdev *evdev;
798 	int minor;
799 	int error;
800 
801 	for (minor = 0; minor < EVDEV_MINORS; minor++)
802 		if (!evdev_table[minor])
803 			break;
804 
805 	if (minor == EVDEV_MINORS) {
806 		printk(KERN_ERR "evdev: no more free evdev devices\n");
807 		return -ENFILE;
808 	}
809 
810 	evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
811 	if (!evdev)
812 		return -ENOMEM;
813 
814 	INIT_LIST_HEAD(&evdev->client_list);
815 	spin_lock_init(&evdev->client_lock);
816 	mutex_init(&evdev->mutex);
817 	init_waitqueue_head(&evdev->wait);
818 
819 	dev_set_name(&evdev->dev, "event%d", minor);
820 	evdev->exist = 1;
821 	evdev->minor = minor;
822 
823 	evdev->handle.dev = input_get_device(dev);
824 	evdev->handle.name = dev_name(&evdev->dev);
825 	evdev->handle.handler = handler;
826 	evdev->handle.private = evdev;
827 
828 	evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
829 	evdev->dev.class = &input_class;
830 	evdev->dev.parent = &dev->dev;
831 	evdev->dev.release = evdev_free;
832 	device_initialize(&evdev->dev);
833 
834 	error = input_register_handle(&evdev->handle);
835 	if (error)
836 		goto err_free_evdev;
837 
838 	error = evdev_install_chrdev(evdev);
839 	if (error)
840 		goto err_unregister_handle;
841 
842 	error = device_add(&evdev->dev);
843 	if (error)
844 		goto err_cleanup_evdev;
845 
846 	return 0;
847 
848  err_cleanup_evdev:
849 	evdev_cleanup(evdev);
850  err_unregister_handle:
851 	input_unregister_handle(&evdev->handle);
852  err_free_evdev:
853 	put_device(&evdev->dev);
854 	return error;
855 }
856 
857 static void evdev_disconnect(struct input_handle *handle)
858 {
859 	struct evdev *evdev = handle->private;
860 
861 	device_del(&evdev->dev);
862 	evdev_cleanup(evdev);
863 	input_unregister_handle(handle);
864 	put_device(&evdev->dev);
865 }
866 
867 static const struct input_device_id evdev_ids[] = {
868 	{ .driver_info = 1 },	/* Matches all devices */
869 	{ },			/* Terminating zero entry */
870 };
871 
872 MODULE_DEVICE_TABLE(input, evdev_ids);
873 
874 static struct input_handler evdev_handler = {
875 	.event		= evdev_event,
876 	.connect	= evdev_connect,
877 	.disconnect	= evdev_disconnect,
878 	.fops		= &evdev_fops,
879 	.minor		= EVDEV_MINOR_BASE,
880 	.name		= "evdev",
881 	.id_table	= evdev_ids,
882 };
883 
884 static int __init evdev_init(void)
885 {
886 	return input_register_handler(&evdev_handler);
887 }
888 
889 static void __exit evdev_exit(void)
890 {
891 	input_unregister_handler(&evdev_handler);
892 }
893 
894 module_init(evdev_init);
895 module_exit(evdev_exit);
896 
897 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
898 MODULE_DESCRIPTION("Input driver event char devices");
899 MODULE_LICENSE("GPL");
900