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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/slab.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/input.h>
20 #include <linux/major.h>
21 #include <linux/device.h>
22 #include <linux/wakelock.h>
23 #include "input-compat.h"
24 
25 struct evdev {
26 	int exist;
27 	int open;
28 	int minor;
29 	char name[16];
30 	struct input_handle handle;
31 	wait_queue_head_t wait;
32 	struct evdev_client *grab;
33 	struct list_head client_list;
34 	spinlock_t client_lock; /* protects client_list */
35 	struct mutex mutex;
36 	struct device dev;
37 };
38 
39 struct evdev_client {
40 	struct input_event buffer[EVDEV_BUFFER_SIZE];
41 	int head;
42 	int tail;
43 	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
44 	struct fasync_struct *fasync;
45 	struct evdev *evdev;
46 	struct list_head node;
47 	struct wake_lock wake_lock;
48 	char name[28];
49 };
50 
51 static struct evdev *evdev_table[EVDEV_MINORS];
52 static DEFINE_MUTEX(evdev_table_mutex);
53 
evdev_pass_event(struct evdev_client * client,struct input_event * event)54 static void evdev_pass_event(struct evdev_client *client,
55 			     struct input_event *event)
56 {
57 	/*
58 	 * Interrupts are disabled, just acquire the lock
59 	 */
60 	spin_lock(&client->buffer_lock);
61 	wake_lock_timeout(&client->wake_lock, 5 * HZ);
62 	client->buffer[client->head++] = *event;
63 	client->head &= EVDEV_BUFFER_SIZE - 1;
64 	spin_unlock(&client->buffer_lock);
65 
66 	kill_fasync(&client->fasync, SIGIO, POLL_IN);
67 }
68 
69 /*
70  * Pass incoming event to all connected clients.
71  */
evdev_event(struct input_handle * handle,unsigned int type,unsigned int code,int value)72 static void evdev_event(struct input_handle *handle,
73 			unsigned int type, unsigned int code, int value)
74 {
75 	struct evdev *evdev = handle->private;
76 	struct evdev_client *client;
77 	struct input_event event;
78 	struct timespec ts;
79 
80 	ktime_get_ts(&ts);
81 	event.time.tv_sec = ts.tv_sec;
82 	event.time.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
83 	event.type = type;
84 	event.code = code;
85 	event.value = value;
86 
87 	rcu_read_lock();
88 
89 	client = rcu_dereference(evdev->grab);
90 	if (client)
91 		evdev_pass_event(client, &event);
92 	else
93 		list_for_each_entry_rcu(client, &evdev->client_list, node)
94 			evdev_pass_event(client, &event);
95 
96 	rcu_read_unlock();
97 
98 	wake_up_interruptible(&evdev->wait);
99 }
100 
evdev_fasync(int fd,struct file * file,int on)101 static int evdev_fasync(int fd, struct file *file, int on)
102 {
103 	struct evdev_client *client = file->private_data;
104 	int retval;
105 
106 	retval = fasync_helper(fd, file, on, &client->fasync);
107 
108 	return retval < 0 ? retval : 0;
109 }
110 
evdev_flush(struct file * file,fl_owner_t id)111 static int evdev_flush(struct file *file, fl_owner_t id)
112 {
113 	struct evdev_client *client = file->private_data;
114 	struct evdev *evdev = client->evdev;
115 	int retval;
116 
117 	retval = mutex_lock_interruptible(&evdev->mutex);
118 	if (retval)
119 		return retval;
120 
121 	if (!evdev->exist)
122 		retval = -ENODEV;
123 	else
124 		retval = input_flush_device(&evdev->handle, file);
125 
126 	mutex_unlock(&evdev->mutex);
127 	return retval;
128 }
129 
evdev_free(struct device * dev)130 static void evdev_free(struct device *dev)
131 {
132 	struct evdev *evdev = container_of(dev, struct evdev, dev);
133 
134 	input_put_device(evdev->handle.dev);
135 	kfree(evdev);
136 }
137 
138 /*
139  * Grabs an event device (along with underlying input device).
140  * This function is called with evdev->mutex taken.
141  */
evdev_grab(struct evdev * evdev,struct evdev_client * client)142 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
143 {
144 	int error;
145 
146 	if (evdev->grab)
147 		return -EBUSY;
148 
149 	error = input_grab_device(&evdev->handle);
150 	if (error)
151 		return error;
152 
153 	rcu_assign_pointer(evdev->grab, client);
154 	synchronize_rcu();
155 
156 	return 0;
157 }
158 
evdev_ungrab(struct evdev * evdev,struct evdev_client * client)159 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
160 {
161 	if (evdev->grab != client)
162 		return  -EINVAL;
163 
164 	rcu_assign_pointer(evdev->grab, NULL);
165 	synchronize_rcu();
166 	input_release_device(&evdev->handle);
167 
168 	return 0;
169 }
170 
evdev_attach_client(struct evdev * evdev,struct evdev_client * client)171 static void evdev_attach_client(struct evdev *evdev,
172 				struct evdev_client *client)
173 {
174 	spin_lock(&evdev->client_lock);
175 	list_add_tail_rcu(&client->node, &evdev->client_list);
176 	spin_unlock(&evdev->client_lock);
177 	synchronize_rcu();
178 }
179 
evdev_detach_client(struct evdev * evdev,struct evdev_client * client)180 static void evdev_detach_client(struct evdev *evdev,
181 				struct evdev_client *client)
182 {
183 	spin_lock(&evdev->client_lock);
184 	list_del_rcu(&client->node);
185 	spin_unlock(&evdev->client_lock);
186 	synchronize_rcu();
187 }
188 
evdev_open_device(struct evdev * evdev)189 static int evdev_open_device(struct evdev *evdev)
190 {
191 	int retval;
192 
193 	retval = mutex_lock_interruptible(&evdev->mutex);
194 	if (retval)
195 		return retval;
196 
197 	if (!evdev->exist)
198 		retval = -ENODEV;
199 	else if (!evdev->open++) {
200 		retval = input_open_device(&evdev->handle);
201 		if (retval)
202 			evdev->open--;
203 	}
204 
205 	mutex_unlock(&evdev->mutex);
206 	return retval;
207 }
208 
evdev_close_device(struct evdev * evdev)209 static void evdev_close_device(struct evdev *evdev)
210 {
211 	mutex_lock(&evdev->mutex);
212 
213 	if (evdev->exist && !--evdev->open)
214 		input_close_device(&evdev->handle);
215 
216 	mutex_unlock(&evdev->mutex);
217 }
218 
219 /*
220  * Wake up users waiting for IO so they can disconnect from
221  * dead device.
222  */
evdev_hangup(struct evdev * evdev)223 static void evdev_hangup(struct evdev *evdev)
224 {
225 	struct evdev_client *client;
226 
227 	spin_lock(&evdev->client_lock);
228 	list_for_each_entry(client, &evdev->client_list, node)
229 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
230 	spin_unlock(&evdev->client_lock);
231 
232 	wake_up_interruptible(&evdev->wait);
233 }
234 
evdev_release(struct inode * inode,struct file * file)235 static int evdev_release(struct inode *inode, struct file *file)
236 {
237 	struct evdev_client *client = file->private_data;
238 	struct evdev *evdev = client->evdev;
239 
240 	mutex_lock(&evdev->mutex);
241 	if (evdev->grab == client)
242 		evdev_ungrab(evdev, client);
243 	mutex_unlock(&evdev->mutex);
244 
245 	evdev_detach_client(evdev, client);
246 	wake_lock_destroy(&client->wake_lock);
247 	kfree(client);
248 
249 	evdev_close_device(evdev);
250 	put_device(&evdev->dev);
251 
252 	return 0;
253 }
254 
evdev_open(struct inode * inode,struct file * file)255 static int evdev_open(struct inode *inode, struct file *file)
256 {
257 	struct evdev *evdev;
258 	struct evdev_client *client;
259 	int i = iminor(inode) - EVDEV_MINOR_BASE;
260 	int error;
261 
262 	if (i >= EVDEV_MINORS)
263 		return -ENODEV;
264 
265 	error = mutex_lock_interruptible(&evdev_table_mutex);
266 	if (error)
267 		return error;
268 	evdev = evdev_table[i];
269 	if (evdev)
270 		get_device(&evdev->dev);
271 	mutex_unlock(&evdev_table_mutex);
272 
273 	if (!evdev)
274 		return -ENODEV;
275 
276 	client = kzalloc(sizeof(struct evdev_client), GFP_KERNEL);
277 	if (!client) {
278 		error = -ENOMEM;
279 		goto err_put_evdev;
280 	}
281 
282 	spin_lock_init(&client->buffer_lock);
283 	snprintf(client->name, sizeof(client->name), "%s-%d", evdev->name,
284 			task_tgid_vnr(current));
285 	wake_lock_init(&client->wake_lock, WAKE_LOCK_SUSPEND, client->name);
286 	client->evdev = evdev;
287 	evdev_attach_client(evdev, client);
288 
289 	error = evdev_open_device(evdev);
290 	if (error)
291 		goto err_free_client;
292 
293 	file->private_data = client;
294 	return 0;
295 
296  err_free_client:
297 	evdev_detach_client(evdev, client);
298 	kfree(client);
299  err_put_evdev:
300 	put_device(&evdev->dev);
301 	return error;
302 }
303 
evdev_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)304 static ssize_t evdev_write(struct file *file, const char __user *buffer,
305 			   size_t count, loff_t *ppos)
306 {
307 	struct evdev_client *client = file->private_data;
308 	struct evdev *evdev = client->evdev;
309 	struct input_event event;
310 	int retval;
311 
312 	retval = mutex_lock_interruptible(&evdev->mutex);
313 	if (retval)
314 		return retval;
315 
316 	if (!evdev->exist) {
317 		retval = -ENODEV;
318 		goto out;
319 	}
320 
321 	while (retval < count) {
322 
323 		if (input_event_from_user(buffer + retval, &event)) {
324 			retval = -EFAULT;
325 			goto out;
326 		}
327 
328 		input_inject_event(&evdev->handle,
329 				   event.type, event.code, event.value);
330 		retval += input_event_size();
331 	}
332 
333  out:
334 	mutex_unlock(&evdev->mutex);
335 	return retval;
336 }
337 
evdev_fetch_next_event(struct evdev_client * client,struct input_event * event)338 static int evdev_fetch_next_event(struct evdev_client *client,
339 				  struct input_event *event)
340 {
341 	int have_event;
342 
343 	spin_lock_irq(&client->buffer_lock);
344 
345 	have_event = client->head != client->tail;
346 	if (have_event) {
347 		*event = client->buffer[client->tail++];
348 		client->tail &= EVDEV_BUFFER_SIZE - 1;
349 		if (client->head == client->tail)
350 			wake_unlock(&client->wake_lock);
351 	}
352 
353 	spin_unlock_irq(&client->buffer_lock);
354 
355 	return have_event;
356 }
357 
evdev_read(struct file * file,char __user * buffer,size_t count,loff_t * ppos)358 static ssize_t evdev_read(struct file *file, char __user *buffer,
359 			  size_t count, loff_t *ppos)
360 {
361 	struct evdev_client *client = file->private_data;
362 	struct evdev *evdev = client->evdev;
363 	struct input_event event;
364 	int retval;
365 
366 	if (count < input_event_size())
367 		return -EINVAL;
368 
369 	if (client->head == client->tail && evdev->exist &&
370 	    (file->f_flags & O_NONBLOCK))
371 		return -EAGAIN;
372 
373 	retval = wait_event_interruptible(evdev->wait,
374 		client->head != client->tail || !evdev->exist);
375 	if (retval)
376 		return retval;
377 
378 	if (!evdev->exist)
379 		return -ENODEV;
380 
381 	while (retval + input_event_size() <= count &&
382 	       evdev_fetch_next_event(client, &event)) {
383 
384 		if (input_event_to_user(buffer + retval, &event))
385 			return -EFAULT;
386 
387 		retval += input_event_size();
388 	}
389 
390 	return retval;
391 }
392 
393 /* No kernel lock - fine */
evdev_poll(struct file * file,poll_table * wait)394 static unsigned int evdev_poll(struct file *file, poll_table *wait)
395 {
396 	struct evdev_client *client = file->private_data;
397 	struct evdev *evdev = client->evdev;
398 
399 	poll_wait(file, &evdev->wait, wait);
400 	return ((client->head == client->tail) ? 0 : (POLLIN | POLLRDNORM)) |
401 		(evdev->exist ? 0 : (POLLHUP | POLLERR));
402 }
403 
404 #ifdef CONFIG_COMPAT
405 
406 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
407 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
408 
409 #ifdef __BIG_ENDIAN
bits_to_user(unsigned long * bits,unsigned int maxbit,unsigned int maxlen,void __user * p,int compat)410 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
411 			unsigned int maxlen, void __user *p, int compat)
412 {
413 	int len, i;
414 
415 	if (compat) {
416 		len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
417 		if (len > maxlen)
418 			len = maxlen;
419 
420 		for (i = 0; i < len / sizeof(compat_long_t); i++)
421 			if (copy_to_user((compat_long_t __user *) p + i,
422 					 (compat_long_t *) bits +
423 						i + 1 - ((i % 2) << 1),
424 					 sizeof(compat_long_t)))
425 				return -EFAULT;
426 	} else {
427 		len = BITS_TO_LONGS(maxbit) * sizeof(long);
428 		if (len > maxlen)
429 			len = maxlen;
430 
431 		if (copy_to_user(p, bits, len))
432 			return -EFAULT;
433 	}
434 
435 	return len;
436 }
437 #else
bits_to_user(unsigned long * bits,unsigned int maxbit,unsigned int maxlen,void __user * p,int compat)438 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
439 			unsigned int maxlen, void __user *p, int compat)
440 {
441 	int len = compat ?
442 			BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
443 			BITS_TO_LONGS(maxbit) * sizeof(long);
444 
445 	if (len > maxlen)
446 		len = maxlen;
447 
448 	return copy_to_user(p, bits, len) ? -EFAULT : len;
449 }
450 #endif /* __BIG_ENDIAN */
451 
452 #else
453 
bits_to_user(unsigned long * bits,unsigned int maxbit,unsigned int maxlen,void __user * p,int compat)454 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
455 			unsigned int maxlen, void __user *p, int compat)
456 {
457 	int len = BITS_TO_LONGS(maxbit) * sizeof(long);
458 
459 	if (len > maxlen)
460 		len = maxlen;
461 
462 	return copy_to_user(p, bits, len) ? -EFAULT : len;
463 }
464 
465 #endif /* CONFIG_COMPAT */
466 
str_to_user(const char * str,unsigned int maxlen,void __user * p)467 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
468 {
469 	int len;
470 
471 	if (!str)
472 		return -ENOENT;
473 
474 	len = strlen(str) + 1;
475 	if (len > maxlen)
476 		len = maxlen;
477 
478 	return copy_to_user(p, str, len) ? -EFAULT : len;
479 }
480 
481 #define OLD_KEY_MAX	0x1ff
handle_eviocgbit(struct input_dev * dev,unsigned int cmd,void __user * p,int compat_mode)482 static int handle_eviocgbit(struct input_dev *dev, unsigned int cmd, void __user *p, int compat_mode)
483 {
484 	static unsigned long keymax_warn_time;
485 	unsigned long *bits;
486 	int len;
487 
488 	switch (_IOC_NR(cmd) & EV_MAX) {
489 
490 	case      0: bits = dev->evbit;  len = EV_MAX;  break;
491 	case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
492 	case EV_REL: bits = dev->relbit; len = REL_MAX; break;
493 	case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
494 	case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
495 	case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
496 	case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
497 	case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
498 	case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
499 	default: return -EINVAL;
500 	}
501 
502 	/*
503 	 * Work around bugs in userspace programs that like to do
504 	 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
505 	 * should be in bytes, not in bits.
506 	 */
507 	if ((_IOC_NR(cmd) & EV_MAX) == EV_KEY && _IOC_SIZE(cmd) == OLD_KEY_MAX) {
508 		len = OLD_KEY_MAX;
509 		if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
510 			printk(KERN_WARNING
511 				"evdev.c(EVIOCGBIT): Suspicious buffer size %u, "
512 				"limiting output to %zu bytes. See "
513 				"http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
514 				OLD_KEY_MAX,
515 				BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
516 	}
517 
518 	return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
519 }
520 #undef OLD_KEY_MAX
521 
evdev_do_ioctl(struct file * file,unsigned int cmd,void __user * p,int compat_mode)522 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
523 			   void __user *p, int compat_mode)
524 {
525 	struct evdev_client *client = file->private_data;
526 	struct evdev *evdev = client->evdev;
527 	struct input_dev *dev = evdev->handle.dev;
528 	struct input_absinfo abs;
529 	struct ff_effect effect;
530 	int __user *ip = (int __user *)p;
531 	int i, t, u, v;
532 	int error;
533 
534 	switch (cmd) {
535 
536 	case EVIOCGVERSION:
537 		return put_user(EV_VERSION, ip);
538 
539 	case EVIOCGID:
540 		if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
541 			return -EFAULT;
542 		return 0;
543 
544 	case EVIOCGREP:
545 		if (!test_bit(EV_REP, dev->evbit))
546 			return -ENOSYS;
547 		if (put_user(dev->rep[REP_DELAY], ip))
548 			return -EFAULT;
549 		if (put_user(dev->rep[REP_PERIOD], ip + 1))
550 			return -EFAULT;
551 		return 0;
552 
553 	case EVIOCSREP:
554 		if (!test_bit(EV_REP, dev->evbit))
555 			return -ENOSYS;
556 		if (get_user(u, ip))
557 			return -EFAULT;
558 		if (get_user(v, ip + 1))
559 			return -EFAULT;
560 
561 		input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
562 		input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
563 
564 		return 0;
565 
566 	case EVIOCGKEYCODE:
567 		if (get_user(t, ip))
568 			return -EFAULT;
569 
570 		error = input_get_keycode(dev, t, &v);
571 		if (error)
572 			return error;
573 
574 		if (put_user(v, ip + 1))
575 			return -EFAULT;
576 
577 		return 0;
578 
579 	case EVIOCSKEYCODE:
580 		if (get_user(t, ip) || get_user(v, ip + 1))
581 			return -EFAULT;
582 
583 		return input_set_keycode(dev, t, v);
584 
585 	case EVIOCRMFF:
586 		return input_ff_erase(dev, (int)(unsigned long) p, file);
587 
588 	case EVIOCGEFFECTS:
589 		i = test_bit(EV_FF, dev->evbit) ?
590 				dev->ff->max_effects : 0;
591 		if (put_user(i, ip))
592 			return -EFAULT;
593 		return 0;
594 
595 	case EVIOCGRAB:
596 		if (p)
597 			return evdev_grab(evdev, client);
598 		else
599 			return evdev_ungrab(evdev, client);
600 
601 	default:
602 
603 		if (_IOC_TYPE(cmd) != 'E')
604 			return -EINVAL;
605 
606 		if (_IOC_DIR(cmd) == _IOC_READ) {
607 
608 			if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
609 				return handle_eviocgbit(dev, cmd, p, compat_mode);
610 
611 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))
612 				return bits_to_user(dev->key, KEY_MAX, _IOC_SIZE(cmd),
613 						    p, compat_mode);
614 
615 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGLED(0)))
616 				return bits_to_user(dev->led, LED_MAX, _IOC_SIZE(cmd),
617 						    p, compat_mode);
618 
619 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSND(0)))
620 				return bits_to_user(dev->snd, SND_MAX, _IOC_SIZE(cmd),
621 						    p, compat_mode);
622 
623 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSW(0)))
624 				return bits_to_user(dev->sw, SW_MAX, _IOC_SIZE(cmd),
625 						    p, compat_mode);
626 
627 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGNAME(0)))
628 				return str_to_user(dev->name, _IOC_SIZE(cmd), p);
629 
630 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGPHYS(0)))
631 				return str_to_user(dev->phys, _IOC_SIZE(cmd), p);
632 
633 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCGUNIQ(0)))
634 				return str_to_user(dev->uniq, _IOC_SIZE(cmd), p);
635 
636 			if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
637 
638 				t = _IOC_NR(cmd) & ABS_MAX;
639 
640 				abs.value = dev->abs[t];
641 				abs.minimum = dev->absmin[t];
642 				abs.maximum = dev->absmax[t];
643 				abs.fuzz = dev->absfuzz[t];
644 				abs.flat = dev->absflat[t];
645 
646 				if (copy_to_user(p, &abs, sizeof(struct input_absinfo)))
647 					return -EFAULT;
648 
649 				return 0;
650 			}
651 
652 		}
653 
654 		if (_IOC_DIR(cmd) == _IOC_WRITE) {
655 
656 			if (_IOC_NR(cmd) == _IOC_NR(EVIOCSFF)) {
657 
658 				if (input_ff_effect_from_user(p, _IOC_SIZE(cmd), &effect))
659 					return -EFAULT;
660 
661 				error = input_ff_upload(dev, &effect, file);
662 
663 				if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
664 					return -EFAULT;
665 
666 				return error;
667 			}
668 
669 			if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
670 
671 				t = _IOC_NR(cmd) & ABS_MAX;
672 
673 				if (copy_from_user(&abs, p,
674 						sizeof(struct input_absinfo)))
675 					return -EFAULT;
676 
677 				/*
678 				 * Take event lock to ensure that we are not
679 				 * changing device parameters in the middle
680 				 * of event.
681 				 */
682 				spin_lock_irq(&dev->event_lock);
683 
684 				dev->abs[t] = abs.value;
685 				dev->absmin[t] = abs.minimum;
686 				dev->absmax[t] = abs.maximum;
687 				dev->absfuzz[t] = abs.fuzz;
688 				dev->absflat[t] = abs.flat;
689 
690 				spin_unlock_irq(&dev->event_lock);
691 
692 				return 0;
693 			}
694 		}
695 	}
696 	return -EINVAL;
697 }
698 
evdev_ioctl_handler(struct file * file,unsigned int cmd,void __user * p,int compat_mode)699 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
700 				void __user *p, int compat_mode)
701 {
702 	struct evdev_client *client = file->private_data;
703 	struct evdev *evdev = client->evdev;
704 	int retval;
705 
706 	retval = mutex_lock_interruptible(&evdev->mutex);
707 	if (retval)
708 		return retval;
709 
710 	if (!evdev->exist) {
711 		retval = -ENODEV;
712 		goto out;
713 	}
714 
715 	retval = evdev_do_ioctl(file, cmd, p, compat_mode);
716 
717  out:
718 	mutex_unlock(&evdev->mutex);
719 	return retval;
720 }
721 
evdev_ioctl(struct file * file,unsigned int cmd,unsigned long arg)722 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
723 {
724 	return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
725 }
726 
727 #ifdef CONFIG_COMPAT
evdev_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)728 static long evdev_ioctl_compat(struct file *file,
729 				unsigned int cmd, unsigned long arg)
730 {
731 	return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
732 }
733 #endif
734 
735 static const struct file_operations evdev_fops = {
736 	.owner		= THIS_MODULE,
737 	.read		= evdev_read,
738 	.write		= evdev_write,
739 	.poll		= evdev_poll,
740 	.open		= evdev_open,
741 	.release	= evdev_release,
742 	.unlocked_ioctl	= evdev_ioctl,
743 #ifdef CONFIG_COMPAT
744 	.compat_ioctl	= evdev_ioctl_compat,
745 #endif
746 	.fasync		= evdev_fasync,
747 	.flush		= evdev_flush
748 };
749 
evdev_install_chrdev(struct evdev * evdev)750 static int evdev_install_chrdev(struct evdev *evdev)
751 {
752 	/*
753 	 * No need to do any locking here as calls to connect and
754 	 * disconnect are serialized by the input core
755 	 */
756 	evdev_table[evdev->minor] = evdev;
757 	return 0;
758 }
759 
evdev_remove_chrdev(struct evdev * evdev)760 static void evdev_remove_chrdev(struct evdev *evdev)
761 {
762 	/*
763 	 * Lock evdev table to prevent race with evdev_open()
764 	 */
765 	mutex_lock(&evdev_table_mutex);
766 	evdev_table[evdev->minor] = NULL;
767 	mutex_unlock(&evdev_table_mutex);
768 }
769 
770 /*
771  * Mark device non-existent. This disables writes, ioctls and
772  * prevents new users from opening the device. Already posted
773  * blocking reads will stay, however new ones will fail.
774  */
evdev_mark_dead(struct evdev * evdev)775 static void evdev_mark_dead(struct evdev *evdev)
776 {
777 	mutex_lock(&evdev->mutex);
778 	evdev->exist = 0;
779 	mutex_unlock(&evdev->mutex);
780 }
781 
evdev_cleanup(struct evdev * evdev)782 static void evdev_cleanup(struct evdev *evdev)
783 {
784 	struct input_handle *handle = &evdev->handle;
785 
786 	evdev_mark_dead(evdev);
787 	evdev_hangup(evdev);
788 	evdev_remove_chrdev(evdev);
789 
790 	/* evdev is marked dead so no one else accesses evdev->open */
791 	if (evdev->open) {
792 		input_flush_device(handle, NULL);
793 		input_close_device(handle);
794 	}
795 }
796 
797 /*
798  * Create new evdev device. Note that input core serializes calls
799  * to connect and disconnect so we don't need to lock evdev_table here.
800  */
evdev_connect(struct input_handler * handler,struct input_dev * dev,const struct input_device_id * id)801 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
802 			 const struct input_device_id *id)
803 {
804 	struct evdev *evdev;
805 	int minor;
806 	int error;
807 
808 	for (minor = 0; minor < EVDEV_MINORS; minor++)
809 		if (!evdev_table[minor])
810 			break;
811 
812 	if (minor == EVDEV_MINORS) {
813 		printk(KERN_ERR "evdev: no more free evdev devices\n");
814 		return -ENFILE;
815 	}
816 
817 	evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
818 	if (!evdev)
819 		return -ENOMEM;
820 
821 	INIT_LIST_HEAD(&evdev->client_list);
822 	spin_lock_init(&evdev->client_lock);
823 	mutex_init(&evdev->mutex);
824 	init_waitqueue_head(&evdev->wait);
825 
826 	snprintf(evdev->name, sizeof(evdev->name), "event%d", minor);
827 	evdev->exist = 1;
828 	evdev->minor = minor;
829 
830 	evdev->handle.dev = input_get_device(dev);
831 	evdev->handle.name = evdev->name;
832 	evdev->handle.handler = handler;
833 	evdev->handle.private = evdev;
834 
835 	dev_set_name(&evdev->dev, evdev->name);
836 	evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
837 	evdev->dev.class = &input_class;
838 	evdev->dev.parent = &dev->dev;
839 	evdev->dev.release = evdev_free;
840 	device_initialize(&evdev->dev);
841 
842 	error = input_register_handle(&evdev->handle);
843 	if (error)
844 		goto err_free_evdev;
845 
846 	error = evdev_install_chrdev(evdev);
847 	if (error)
848 		goto err_unregister_handle;
849 
850 	error = device_add(&evdev->dev);
851 	if (error)
852 		goto err_cleanup_evdev;
853 
854 	return 0;
855 
856  err_cleanup_evdev:
857 	evdev_cleanup(evdev);
858  err_unregister_handle:
859 	input_unregister_handle(&evdev->handle);
860  err_free_evdev:
861 	put_device(&evdev->dev);
862 	return error;
863 }
864 
evdev_disconnect(struct input_handle * handle)865 static void evdev_disconnect(struct input_handle *handle)
866 {
867 	struct evdev *evdev = handle->private;
868 
869 	device_del(&evdev->dev);
870 	evdev_cleanup(evdev);
871 	input_unregister_handle(handle);
872 	put_device(&evdev->dev);
873 }
874 
875 static const struct input_device_id evdev_ids[] = {
876 	{ .driver_info = 1 },	/* Matches all devices */
877 	{ },			/* Terminating zero entry */
878 };
879 
880 MODULE_DEVICE_TABLE(input, evdev_ids);
881 
882 static struct input_handler evdev_handler = {
883 	.event		= evdev_event,
884 	.connect	= evdev_connect,
885 	.disconnect	= evdev_disconnect,
886 	.fops		= &evdev_fops,
887 	.minor		= EVDEV_MINOR_BASE,
888 	.name		= "evdev",
889 	.id_table	= evdev_ids,
890 };
891 
evdev_init(void)892 static int __init evdev_init(void)
893 {
894 	return input_register_handler(&evdev_handler);
895 }
896 
evdev_exit(void)897 static void __exit evdev_exit(void)
898 {
899 	input_unregister_handler(&evdev_handler);
900 }
901 
902 module_init(evdev_init);
903 module_exit(evdev_exit);
904 
905 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
906 MODULE_DESCRIPTION("Input driver event char devices");
907 MODULE_LICENSE("GPL");
908