xref: /openbmc/linux/drivers/input/evdev.c (revision 4ba8b8ae)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Event char devices, giving access to raw input device events.
4  *
5  * Copyright (c) 1999-2002 Vojtech Pavlik
6  */
7 
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 
10 #define EVDEV_MINOR_BASE	64
11 #define EVDEV_MINORS		32
12 #define EVDEV_MIN_BUFFER_SIZE	64U
13 #define EVDEV_BUF_PACKETS	8
14 
15 #include <linux/poll.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/vmalloc.h>
19 #include <linux/mm.h>
20 #include <linux/module.h>
21 #include <linux/init.h>
22 #include <linux/input/mt.h>
23 #include <linux/major.h>
24 #include <linux/device.h>
25 #include <linux/cdev.h>
26 #include "input-compat.h"
27 
28 struct evdev {
29 	int open;
30 	struct input_handle handle;
31 	struct evdev_client __rcu *grab;
32 	struct list_head client_list;
33 	spinlock_t client_lock; /* protects client_list */
34 	struct mutex mutex;
35 	struct device dev;
36 	struct cdev cdev;
37 	bool exist;
38 };
39 
40 struct evdev_client {
41 	unsigned int head;
42 	unsigned int tail;
43 	unsigned int packet_head; /* [future] position of the first element of next packet */
44 	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
45 	wait_queue_head_t wait;
46 	struct fasync_struct *fasync;
47 	struct evdev *evdev;
48 	struct list_head node;
49 	enum input_clock_type clk_type;
50 	bool revoked;
51 	unsigned long *evmasks[EV_CNT];
52 	unsigned int bufsize;
53 	struct input_event buffer[];
54 };
55 
evdev_get_mask_cnt(unsigned int type)56 static size_t evdev_get_mask_cnt(unsigned int type)
57 {
58 	static const size_t counts[EV_CNT] = {
59 		/* EV_SYN==0 is EV_CNT, _not_ SYN_CNT, see EVIOCGBIT */
60 		[EV_SYN]	= EV_CNT,
61 		[EV_KEY]	= KEY_CNT,
62 		[EV_REL]	= REL_CNT,
63 		[EV_ABS]	= ABS_CNT,
64 		[EV_MSC]	= MSC_CNT,
65 		[EV_SW]		= SW_CNT,
66 		[EV_LED]	= LED_CNT,
67 		[EV_SND]	= SND_CNT,
68 		[EV_FF]		= FF_CNT,
69 	};
70 
71 	return (type < EV_CNT) ? counts[type] : 0;
72 }
73 
74 /* requires the buffer lock to be held */
__evdev_is_filtered(struct evdev_client * client,unsigned int type,unsigned int code)75 static bool __evdev_is_filtered(struct evdev_client *client,
76 				unsigned int type,
77 				unsigned int code)
78 {
79 	unsigned long *mask;
80 	size_t cnt;
81 
82 	/* EV_SYN and unknown codes are never filtered */
83 	if (type == EV_SYN || type >= EV_CNT)
84 		return false;
85 
86 	/* first test whether the type is filtered */
87 	mask = client->evmasks[0];
88 	if (mask && !test_bit(type, mask))
89 		return true;
90 
91 	/* unknown values are never filtered */
92 	cnt = evdev_get_mask_cnt(type);
93 	if (!cnt || code >= cnt)
94 		return false;
95 
96 	mask = client->evmasks[type];
97 	return mask && !test_bit(code, mask);
98 }
99 
100 /* flush queued events of type @type, caller must hold client->buffer_lock */
__evdev_flush_queue(struct evdev_client * client,unsigned int type)101 static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
102 {
103 	unsigned int i, head, num;
104 	unsigned int mask = client->bufsize - 1;
105 	bool is_report;
106 	struct input_event *ev;
107 
108 	BUG_ON(type == EV_SYN);
109 
110 	head = client->tail;
111 	client->packet_head = client->tail;
112 
113 	/* init to 1 so a leading SYN_REPORT will not be dropped */
114 	num = 1;
115 
116 	for (i = client->tail; i != client->head; i = (i + 1) & mask) {
117 		ev = &client->buffer[i];
118 		is_report = ev->type == EV_SYN && ev->code == SYN_REPORT;
119 
120 		if (ev->type == type) {
121 			/* drop matched entry */
122 			continue;
123 		} else if (is_report && !num) {
124 			/* drop empty SYN_REPORT groups */
125 			continue;
126 		} else if (head != i) {
127 			/* move entry to fill the gap */
128 			client->buffer[head] = *ev;
129 		}
130 
131 		num++;
132 		head = (head + 1) & mask;
133 
134 		if (is_report) {
135 			num = 0;
136 			client->packet_head = head;
137 		}
138 	}
139 
140 	client->head = head;
141 }
142 
__evdev_queue_syn_dropped(struct evdev_client * client)143 static void __evdev_queue_syn_dropped(struct evdev_client *client)
144 {
145 	ktime_t *ev_time = input_get_timestamp(client->evdev->handle.dev);
146 	struct timespec64 ts = ktime_to_timespec64(ev_time[client->clk_type]);
147 	struct input_event ev;
148 
149 	ev.input_event_sec = ts.tv_sec;
150 	ev.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
151 	ev.type = EV_SYN;
152 	ev.code = SYN_DROPPED;
153 	ev.value = 0;
154 
155 	client->buffer[client->head++] = ev;
156 	client->head &= client->bufsize - 1;
157 
158 	if (unlikely(client->head == client->tail)) {
159 		/* drop queue but keep our SYN_DROPPED event */
160 		client->tail = (client->head - 1) & (client->bufsize - 1);
161 		client->packet_head = client->tail;
162 	}
163 }
164 
evdev_queue_syn_dropped(struct evdev_client * client)165 static void evdev_queue_syn_dropped(struct evdev_client *client)
166 {
167 	unsigned long flags;
168 
169 	spin_lock_irqsave(&client->buffer_lock, flags);
170 	__evdev_queue_syn_dropped(client);
171 	spin_unlock_irqrestore(&client->buffer_lock, flags);
172 }
173 
evdev_set_clk_type(struct evdev_client * client,unsigned int clkid)174 static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid)
175 {
176 	unsigned long flags;
177 	enum input_clock_type clk_type;
178 
179 	switch (clkid) {
180 
181 	case CLOCK_REALTIME:
182 		clk_type = INPUT_CLK_REAL;
183 		break;
184 	case CLOCK_MONOTONIC:
185 		clk_type = INPUT_CLK_MONO;
186 		break;
187 	case CLOCK_BOOTTIME:
188 		clk_type = INPUT_CLK_BOOT;
189 		break;
190 	default:
191 		return -EINVAL;
192 	}
193 
194 	if (client->clk_type != clk_type) {
195 		client->clk_type = clk_type;
196 
197 		/*
198 		 * Flush pending events and queue SYN_DROPPED event,
199 		 * but only if the queue is not empty.
200 		 */
201 		spin_lock_irqsave(&client->buffer_lock, flags);
202 
203 		if (client->head != client->tail) {
204 			client->packet_head = client->head = client->tail;
205 			__evdev_queue_syn_dropped(client);
206 		}
207 
208 		spin_unlock_irqrestore(&client->buffer_lock, flags);
209 	}
210 
211 	return 0;
212 }
213 
__pass_event(struct evdev_client * client,const struct input_event * event)214 static void __pass_event(struct evdev_client *client,
215 			 const struct input_event *event)
216 {
217 	client->buffer[client->head++] = *event;
218 	client->head &= client->bufsize - 1;
219 
220 	if (unlikely(client->head == client->tail)) {
221 		/*
222 		 * This effectively "drops" all unconsumed events, leaving
223 		 * EV_SYN/SYN_DROPPED plus the newest event in the queue.
224 		 */
225 		client->tail = (client->head - 2) & (client->bufsize - 1);
226 
227 		client->buffer[client->tail] = (struct input_event) {
228 			.input_event_sec = event->input_event_sec,
229 			.input_event_usec = event->input_event_usec,
230 			.type = EV_SYN,
231 			.code = SYN_DROPPED,
232 			.value = 0,
233 		};
234 
235 		client->packet_head = client->tail;
236 	}
237 
238 	if (event->type == EV_SYN && event->code == SYN_REPORT) {
239 		client->packet_head = client->head;
240 		kill_fasync(&client->fasync, SIGIO, POLL_IN);
241 	}
242 }
243 
evdev_pass_values(struct evdev_client * client,const struct input_value * vals,unsigned int count,ktime_t * ev_time)244 static void evdev_pass_values(struct evdev_client *client,
245 			const struct input_value *vals, unsigned int count,
246 			ktime_t *ev_time)
247 {
248 	const struct input_value *v;
249 	struct input_event event;
250 	struct timespec64 ts;
251 	bool wakeup = false;
252 
253 	if (client->revoked)
254 		return;
255 
256 	ts = ktime_to_timespec64(ev_time[client->clk_type]);
257 	event.input_event_sec = ts.tv_sec;
258 	event.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
259 
260 	/* Interrupts are disabled, just acquire the lock. */
261 	spin_lock(&client->buffer_lock);
262 
263 	for (v = vals; v != vals + count; v++) {
264 		if (__evdev_is_filtered(client, v->type, v->code))
265 			continue;
266 
267 		if (v->type == EV_SYN && v->code == SYN_REPORT) {
268 			/* drop empty SYN_REPORT */
269 			if (client->packet_head == client->head)
270 				continue;
271 
272 			wakeup = true;
273 		}
274 
275 		event.type = v->type;
276 		event.code = v->code;
277 		event.value = v->value;
278 		__pass_event(client, &event);
279 	}
280 
281 	spin_unlock(&client->buffer_lock);
282 
283 	if (wakeup)
284 		wake_up_interruptible_poll(&client->wait,
285 			EPOLLIN | EPOLLOUT | EPOLLRDNORM | EPOLLWRNORM);
286 }
287 
288 /*
289  * Pass incoming events to all connected clients.
290  */
evdev_events(struct input_handle * handle,const struct input_value * vals,unsigned int count)291 static void evdev_events(struct input_handle *handle,
292 			 const struct input_value *vals, unsigned int count)
293 {
294 	struct evdev *evdev = handle->private;
295 	struct evdev_client *client;
296 	ktime_t *ev_time = input_get_timestamp(handle->dev);
297 
298 	rcu_read_lock();
299 
300 	client = rcu_dereference(evdev->grab);
301 
302 	if (client)
303 		evdev_pass_values(client, vals, count, ev_time);
304 	else
305 		list_for_each_entry_rcu(client, &evdev->client_list, node)
306 			evdev_pass_values(client, vals, count, ev_time);
307 
308 	rcu_read_unlock();
309 }
310 
311 /*
312  * Pass incoming event to all connected clients.
313  */
evdev_event(struct input_handle * handle,unsigned int type,unsigned int code,int value)314 static void evdev_event(struct input_handle *handle,
315 			unsigned int type, unsigned int code, int value)
316 {
317 	struct input_value vals[] = { { type, code, value } };
318 
319 	evdev_events(handle, vals, 1);
320 }
321 
evdev_fasync(int fd,struct file * file,int on)322 static int evdev_fasync(int fd, struct file *file, int on)
323 {
324 	struct evdev_client *client = file->private_data;
325 
326 	return fasync_helper(fd, file, on, &client->fasync);
327 }
328 
evdev_free(struct device * dev)329 static void evdev_free(struct device *dev)
330 {
331 	struct evdev *evdev = container_of(dev, struct evdev, dev);
332 
333 	input_put_device(evdev->handle.dev);
334 	kfree(evdev);
335 }
336 
337 /*
338  * Grabs an event device (along with underlying input device).
339  * This function is called with evdev->mutex taken.
340  */
evdev_grab(struct evdev * evdev,struct evdev_client * client)341 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
342 {
343 	int error;
344 
345 	if (evdev->grab)
346 		return -EBUSY;
347 
348 	error = input_grab_device(&evdev->handle);
349 	if (error)
350 		return error;
351 
352 	rcu_assign_pointer(evdev->grab, client);
353 
354 	return 0;
355 }
356 
evdev_ungrab(struct evdev * evdev,struct evdev_client * client)357 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
358 {
359 	struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
360 					lockdep_is_held(&evdev->mutex));
361 
362 	if (grab != client)
363 		return  -EINVAL;
364 
365 	rcu_assign_pointer(evdev->grab, NULL);
366 	synchronize_rcu();
367 	input_release_device(&evdev->handle);
368 
369 	return 0;
370 }
371 
evdev_attach_client(struct evdev * evdev,struct evdev_client * client)372 static void evdev_attach_client(struct evdev *evdev,
373 				struct evdev_client *client)
374 {
375 	spin_lock(&evdev->client_lock);
376 	list_add_tail_rcu(&client->node, &evdev->client_list);
377 	spin_unlock(&evdev->client_lock);
378 }
379 
evdev_detach_client(struct evdev * evdev,struct evdev_client * client)380 static void evdev_detach_client(struct evdev *evdev,
381 				struct evdev_client *client)
382 {
383 	spin_lock(&evdev->client_lock);
384 	list_del_rcu(&client->node);
385 	spin_unlock(&evdev->client_lock);
386 	synchronize_rcu();
387 }
388 
evdev_open_device(struct evdev * evdev)389 static int evdev_open_device(struct evdev *evdev)
390 {
391 	int retval;
392 
393 	retval = mutex_lock_interruptible(&evdev->mutex);
394 	if (retval)
395 		return retval;
396 
397 	if (!evdev->exist)
398 		retval = -ENODEV;
399 	else if (!evdev->open++) {
400 		retval = input_open_device(&evdev->handle);
401 		if (retval)
402 			evdev->open--;
403 	}
404 
405 	mutex_unlock(&evdev->mutex);
406 	return retval;
407 }
408 
evdev_close_device(struct evdev * evdev)409 static void evdev_close_device(struct evdev *evdev)
410 {
411 	mutex_lock(&evdev->mutex);
412 
413 	if (evdev->exist && !--evdev->open)
414 		input_close_device(&evdev->handle);
415 
416 	mutex_unlock(&evdev->mutex);
417 }
418 
419 /*
420  * Wake up users waiting for IO so they can disconnect from
421  * dead device.
422  */
evdev_hangup(struct evdev * evdev)423 static void evdev_hangup(struct evdev *evdev)
424 {
425 	struct evdev_client *client;
426 
427 	spin_lock(&evdev->client_lock);
428 	list_for_each_entry(client, &evdev->client_list, node) {
429 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
430 		wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR);
431 	}
432 	spin_unlock(&evdev->client_lock);
433 }
434 
evdev_release(struct inode * inode,struct file * file)435 static int evdev_release(struct inode *inode, struct file *file)
436 {
437 	struct evdev_client *client = file->private_data;
438 	struct evdev *evdev = client->evdev;
439 	unsigned int i;
440 
441 	mutex_lock(&evdev->mutex);
442 
443 	if (evdev->exist && !client->revoked)
444 		input_flush_device(&evdev->handle, file);
445 
446 	evdev_ungrab(evdev, client);
447 	mutex_unlock(&evdev->mutex);
448 
449 	evdev_detach_client(evdev, client);
450 
451 	for (i = 0; i < EV_CNT; ++i)
452 		bitmap_free(client->evmasks[i]);
453 
454 	kvfree(client);
455 
456 	evdev_close_device(evdev);
457 
458 	return 0;
459 }
460 
evdev_compute_buffer_size(struct input_dev * dev)461 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
462 {
463 	unsigned int n_events =
464 		max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
465 		    EVDEV_MIN_BUFFER_SIZE);
466 
467 	return roundup_pow_of_two(n_events);
468 }
469 
evdev_open(struct inode * inode,struct file * file)470 static int evdev_open(struct inode *inode, struct file *file)
471 {
472 	struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
473 	unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
474 	struct evdev_client *client;
475 	int error;
476 
477 	client = kvzalloc(struct_size(client, buffer, bufsize), GFP_KERNEL);
478 	if (!client)
479 		return -ENOMEM;
480 
481 	init_waitqueue_head(&client->wait);
482 	client->bufsize = bufsize;
483 	spin_lock_init(&client->buffer_lock);
484 	client->evdev = evdev;
485 	evdev_attach_client(evdev, client);
486 
487 	error = evdev_open_device(evdev);
488 	if (error)
489 		goto err_free_client;
490 
491 	file->private_data = client;
492 	stream_open(inode, file);
493 
494 	return 0;
495 
496  err_free_client:
497 	evdev_detach_client(evdev, client);
498 	kvfree(client);
499 	return error;
500 }
501 
evdev_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)502 static ssize_t evdev_write(struct file *file, const char __user *buffer,
503 			   size_t count, loff_t *ppos)
504 {
505 	struct evdev_client *client = file->private_data;
506 	struct evdev *evdev = client->evdev;
507 	struct input_event event;
508 	int retval = 0;
509 
510 	if (count != 0 && count < input_event_size())
511 		return -EINVAL;
512 
513 	retval = mutex_lock_interruptible(&evdev->mutex);
514 	if (retval)
515 		return retval;
516 
517 	if (!evdev->exist || client->revoked) {
518 		retval = -ENODEV;
519 		goto out;
520 	}
521 
522 	while (retval + input_event_size() <= count) {
523 
524 		if (input_event_from_user(buffer + retval, &event)) {
525 			retval = -EFAULT;
526 			goto out;
527 		}
528 		retval += input_event_size();
529 
530 		input_inject_event(&evdev->handle,
531 				   event.type, event.code, event.value);
532 		cond_resched();
533 	}
534 
535  out:
536 	mutex_unlock(&evdev->mutex);
537 	return retval;
538 }
539 
evdev_fetch_next_event(struct evdev_client * client,struct input_event * event)540 static int evdev_fetch_next_event(struct evdev_client *client,
541 				  struct input_event *event)
542 {
543 	int have_event;
544 
545 	spin_lock_irq(&client->buffer_lock);
546 
547 	have_event = client->packet_head != client->tail;
548 	if (have_event) {
549 		*event = client->buffer[client->tail++];
550 		client->tail &= client->bufsize - 1;
551 	}
552 
553 	spin_unlock_irq(&client->buffer_lock);
554 
555 	return have_event;
556 }
557 
evdev_read(struct file * file,char __user * buffer,size_t count,loff_t * ppos)558 static ssize_t evdev_read(struct file *file, char __user *buffer,
559 			  size_t count, loff_t *ppos)
560 {
561 	struct evdev_client *client = file->private_data;
562 	struct evdev *evdev = client->evdev;
563 	struct input_event event;
564 	size_t read = 0;
565 	int error;
566 
567 	if (count != 0 && count < input_event_size())
568 		return -EINVAL;
569 
570 	for (;;) {
571 		if (!evdev->exist || client->revoked)
572 			return -ENODEV;
573 
574 		if (client->packet_head == client->tail &&
575 		    (file->f_flags & O_NONBLOCK))
576 			return -EAGAIN;
577 
578 		/*
579 		 * count == 0 is special - no IO is done but we check
580 		 * for error conditions (see above).
581 		 */
582 		if (count == 0)
583 			break;
584 
585 		while (read + input_event_size() <= count &&
586 		       evdev_fetch_next_event(client, &event)) {
587 
588 			if (input_event_to_user(buffer + read, &event))
589 				return -EFAULT;
590 
591 			read += input_event_size();
592 		}
593 
594 		if (read)
595 			break;
596 
597 		if (!(file->f_flags & O_NONBLOCK)) {
598 			error = wait_event_interruptible(client->wait,
599 					client->packet_head != client->tail ||
600 					!evdev->exist || client->revoked);
601 			if (error)
602 				return error;
603 		}
604 	}
605 
606 	return read;
607 }
608 
609 /* No kernel lock - fine */
evdev_poll(struct file * file,poll_table * wait)610 static __poll_t evdev_poll(struct file *file, poll_table *wait)
611 {
612 	struct evdev_client *client = file->private_data;
613 	struct evdev *evdev = client->evdev;
614 	__poll_t mask;
615 
616 	poll_wait(file, &client->wait, wait);
617 
618 	if (evdev->exist && !client->revoked)
619 		mask = EPOLLOUT | EPOLLWRNORM;
620 	else
621 		mask = EPOLLHUP | EPOLLERR;
622 
623 	if (client->packet_head != client->tail)
624 		mask |= EPOLLIN | EPOLLRDNORM;
625 
626 	return mask;
627 }
628 
629 #ifdef CONFIG_COMPAT
630 
631 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
632 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
633 
634 #ifdef __BIG_ENDIAN
bits_to_user(unsigned long * bits,unsigned int maxbit,unsigned int maxlen,void __user * p,int compat)635 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
636 			unsigned int maxlen, void __user *p, int compat)
637 {
638 	int len, i;
639 
640 	if (compat) {
641 		len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
642 		if (len > maxlen)
643 			len = maxlen;
644 
645 		for (i = 0; i < len / sizeof(compat_long_t); i++)
646 			if (copy_to_user((compat_long_t __user *) p + i,
647 					 (compat_long_t *) bits +
648 						i + 1 - ((i % 2) << 1),
649 					 sizeof(compat_long_t)))
650 				return -EFAULT;
651 	} else {
652 		len = BITS_TO_LONGS(maxbit) * sizeof(long);
653 		if (len > maxlen)
654 			len = maxlen;
655 
656 		if (copy_to_user(p, bits, len))
657 			return -EFAULT;
658 	}
659 
660 	return len;
661 }
662 
bits_from_user(unsigned long * bits,unsigned int maxbit,unsigned int maxlen,const void __user * p,int compat)663 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
664 			  unsigned int maxlen, const void __user *p, int compat)
665 {
666 	int len, i;
667 
668 	if (compat) {
669 		if (maxlen % sizeof(compat_long_t))
670 			return -EINVAL;
671 
672 		len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
673 		if (len > maxlen)
674 			len = maxlen;
675 
676 		for (i = 0; i < len / sizeof(compat_long_t); i++)
677 			if (copy_from_user((compat_long_t *) bits +
678 						i + 1 - ((i % 2) << 1),
679 					   (compat_long_t __user *) p + i,
680 					   sizeof(compat_long_t)))
681 				return -EFAULT;
682 		if (i % 2)
683 			*((compat_long_t *) bits + i - 1) = 0;
684 
685 	} else {
686 		if (maxlen % sizeof(long))
687 			return -EINVAL;
688 
689 		len = BITS_TO_LONGS(maxbit) * sizeof(long);
690 		if (len > maxlen)
691 			len = maxlen;
692 
693 		if (copy_from_user(bits, p, len))
694 			return -EFAULT;
695 	}
696 
697 	return len;
698 }
699 
700 #else
701 
bits_to_user(unsigned long * bits,unsigned int maxbit,unsigned int maxlen,void __user * p,int compat)702 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
703 			unsigned int maxlen, void __user *p, int compat)
704 {
705 	int len = compat ?
706 			BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
707 			BITS_TO_LONGS(maxbit) * sizeof(long);
708 
709 	if (len > maxlen)
710 		len = maxlen;
711 
712 	return copy_to_user(p, bits, len) ? -EFAULT : len;
713 }
714 
bits_from_user(unsigned long * bits,unsigned int maxbit,unsigned int maxlen,const void __user * p,int compat)715 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
716 			  unsigned int maxlen, const void __user *p, int compat)
717 {
718 	size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long);
719 	int len;
720 
721 	if (maxlen % chunk_size)
722 		return -EINVAL;
723 
724 	len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);
725 	len *= chunk_size;
726 	if (len > maxlen)
727 		len = maxlen;
728 
729 	return copy_from_user(bits, p, len) ? -EFAULT : len;
730 }
731 
732 #endif /* __BIG_ENDIAN */
733 
734 #else
735 
bits_to_user(unsigned long * bits,unsigned int maxbit,unsigned int maxlen,void __user * p,int compat)736 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
737 			unsigned int maxlen, void __user *p, int compat)
738 {
739 	int len = BITS_TO_LONGS(maxbit) * sizeof(long);
740 
741 	if (len > maxlen)
742 		len = maxlen;
743 
744 	return copy_to_user(p, bits, len) ? -EFAULT : len;
745 }
746 
bits_from_user(unsigned long * bits,unsigned int maxbit,unsigned int maxlen,const void __user * p,int compat)747 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
748 			  unsigned int maxlen, const void __user *p, int compat)
749 {
750 	int len;
751 
752 	if (maxlen % sizeof(long))
753 		return -EINVAL;
754 
755 	len = BITS_TO_LONGS(maxbit) * sizeof(long);
756 	if (len > maxlen)
757 		len = maxlen;
758 
759 	return copy_from_user(bits, p, len) ? -EFAULT : len;
760 }
761 
762 #endif /* CONFIG_COMPAT */
763 
str_to_user(const char * str,unsigned int maxlen,void __user * p)764 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
765 {
766 	int len;
767 
768 	if (!str)
769 		return -ENOENT;
770 
771 	len = strlen(str) + 1;
772 	if (len > maxlen)
773 		len = maxlen;
774 
775 	return copy_to_user(p, str, len) ? -EFAULT : len;
776 }
777 
handle_eviocgbit(struct input_dev * dev,unsigned int type,unsigned int size,void __user * p,int compat_mode)778 static int handle_eviocgbit(struct input_dev *dev,
779 			    unsigned int type, unsigned int size,
780 			    void __user *p, int compat_mode)
781 {
782 	unsigned long *bits;
783 	int len;
784 
785 	switch (type) {
786 
787 	case      0: bits = dev->evbit;  len = EV_MAX;  break;
788 	case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
789 	case EV_REL: bits = dev->relbit; len = REL_MAX; break;
790 	case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
791 	case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
792 	case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
793 	case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
794 	case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
795 	case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
796 	default: return -EINVAL;
797 	}
798 
799 	return bits_to_user(bits, len, size, p, compat_mode);
800 }
801 
evdev_handle_get_keycode(struct input_dev * dev,void __user * p)802 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
803 {
804 	struct input_keymap_entry ke = {
805 		.len	= sizeof(unsigned int),
806 		.flags	= 0,
807 	};
808 	int __user *ip = (int __user *)p;
809 	int error;
810 
811 	/* legacy case */
812 	if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
813 		return -EFAULT;
814 
815 	error = input_get_keycode(dev, &ke);
816 	if (error)
817 		return error;
818 
819 	if (put_user(ke.keycode, ip + 1))
820 		return -EFAULT;
821 
822 	return 0;
823 }
824 
evdev_handle_get_keycode_v2(struct input_dev * dev,void __user * p)825 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
826 {
827 	struct input_keymap_entry ke;
828 	int error;
829 
830 	if (copy_from_user(&ke, p, sizeof(ke)))
831 		return -EFAULT;
832 
833 	error = input_get_keycode(dev, &ke);
834 	if (error)
835 		return error;
836 
837 	if (copy_to_user(p, &ke, sizeof(ke)))
838 		return -EFAULT;
839 
840 	return 0;
841 }
842 
evdev_handle_set_keycode(struct input_dev * dev,void __user * p)843 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
844 {
845 	struct input_keymap_entry ke = {
846 		.len	= sizeof(unsigned int),
847 		.flags	= 0,
848 	};
849 	int __user *ip = (int __user *)p;
850 
851 	if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
852 		return -EFAULT;
853 
854 	if (get_user(ke.keycode, ip + 1))
855 		return -EFAULT;
856 
857 	return input_set_keycode(dev, &ke);
858 }
859 
evdev_handle_set_keycode_v2(struct input_dev * dev,void __user * p)860 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
861 {
862 	struct input_keymap_entry ke;
863 
864 	if (copy_from_user(&ke, p, sizeof(ke)))
865 		return -EFAULT;
866 
867 	if (ke.len > sizeof(ke.scancode))
868 		return -EINVAL;
869 
870 	return input_set_keycode(dev, &ke);
871 }
872 
873 /*
874  * If we transfer state to the user, we should flush all pending events
875  * of the same type from the client's queue. Otherwise, they might end up
876  * with duplicate events, which can screw up client's state tracking.
877  * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
878  * event so user-space will notice missing events.
879  *
880  * LOCKING:
881  * We need to take event_lock before buffer_lock to avoid dead-locks. But we
882  * need the even_lock only to guarantee consistent state. We can safely release
883  * it while flushing the queue. This allows input-core to handle filters while
884  * we flush the queue.
885  */
evdev_handle_get_val(struct evdev_client * client,struct input_dev * dev,unsigned int type,unsigned long * bits,unsigned int maxbit,unsigned int maxlen,void __user * p,int compat)886 static int evdev_handle_get_val(struct evdev_client *client,
887 				struct input_dev *dev, unsigned int type,
888 				unsigned long *bits, unsigned int maxbit,
889 				unsigned int maxlen, void __user *p,
890 				int compat)
891 {
892 	int ret;
893 	unsigned long *mem;
894 
895 	mem = bitmap_alloc(maxbit, GFP_KERNEL);
896 	if (!mem)
897 		return -ENOMEM;
898 
899 	spin_lock_irq(&dev->event_lock);
900 	spin_lock(&client->buffer_lock);
901 
902 	bitmap_copy(mem, bits, maxbit);
903 
904 	spin_unlock(&dev->event_lock);
905 
906 	__evdev_flush_queue(client, type);
907 
908 	spin_unlock_irq(&client->buffer_lock);
909 
910 	ret = bits_to_user(mem, maxbit, maxlen, p, compat);
911 	if (ret < 0)
912 		evdev_queue_syn_dropped(client);
913 
914 	bitmap_free(mem);
915 
916 	return ret;
917 }
918 
evdev_handle_mt_request(struct input_dev * dev,unsigned int size,int __user * ip)919 static int evdev_handle_mt_request(struct input_dev *dev,
920 				   unsigned int size,
921 				   int __user *ip)
922 {
923 	const struct input_mt *mt = dev->mt;
924 	unsigned int code;
925 	int max_slots;
926 	int i;
927 
928 	if (get_user(code, &ip[0]))
929 		return -EFAULT;
930 	if (!mt || !input_is_mt_value(code))
931 		return -EINVAL;
932 
933 	max_slots = (size - sizeof(__u32)) / sizeof(__s32);
934 	for (i = 0; i < mt->num_slots && i < max_slots; i++) {
935 		int value = input_mt_get_value(&mt->slots[i], code);
936 		if (put_user(value, &ip[1 + i]))
937 			return -EFAULT;
938 	}
939 
940 	return 0;
941 }
942 
evdev_revoke(struct evdev * evdev,struct evdev_client * client,struct file * file)943 static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
944 			struct file *file)
945 {
946 	client->revoked = true;
947 	evdev_ungrab(evdev, client);
948 	input_flush_device(&evdev->handle, file);
949 	wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR);
950 
951 	return 0;
952 }
953 
954 /* must be called with evdev-mutex held */
evdev_set_mask(struct evdev_client * client,unsigned int type,const void __user * codes,u32 codes_size,int compat)955 static int evdev_set_mask(struct evdev_client *client,
956 			  unsigned int type,
957 			  const void __user *codes,
958 			  u32 codes_size,
959 			  int compat)
960 {
961 	unsigned long flags, *mask, *oldmask;
962 	size_t cnt;
963 	int error;
964 
965 	/* we allow unknown types and 'codes_size > size' for forward-compat */
966 	cnt = evdev_get_mask_cnt(type);
967 	if (!cnt)
968 		return 0;
969 
970 	mask = bitmap_zalloc(cnt, GFP_KERNEL);
971 	if (!mask)
972 		return -ENOMEM;
973 
974 	error = bits_from_user(mask, cnt - 1, codes_size, codes, compat);
975 	if (error < 0) {
976 		bitmap_free(mask);
977 		return error;
978 	}
979 
980 	spin_lock_irqsave(&client->buffer_lock, flags);
981 	oldmask = client->evmasks[type];
982 	client->evmasks[type] = mask;
983 	spin_unlock_irqrestore(&client->buffer_lock, flags);
984 
985 	bitmap_free(oldmask);
986 
987 	return 0;
988 }
989 
990 /* must be called with evdev-mutex held */
evdev_get_mask(struct evdev_client * client,unsigned int type,void __user * codes,u32 codes_size,int compat)991 static int evdev_get_mask(struct evdev_client *client,
992 			  unsigned int type,
993 			  void __user *codes,
994 			  u32 codes_size,
995 			  int compat)
996 {
997 	unsigned long *mask;
998 	size_t cnt, size, xfer_size;
999 	int i;
1000 	int error;
1001 
1002 	/* we allow unknown types and 'codes_size > size' for forward-compat */
1003 	cnt = evdev_get_mask_cnt(type);
1004 	size = sizeof(unsigned long) * BITS_TO_LONGS(cnt);
1005 	xfer_size = min_t(size_t, codes_size, size);
1006 
1007 	if (cnt > 0) {
1008 		mask = client->evmasks[type];
1009 		if (mask) {
1010 			error = bits_to_user(mask, cnt - 1,
1011 					     xfer_size, codes, compat);
1012 			if (error < 0)
1013 				return error;
1014 		} else {
1015 			/* fake mask with all bits set */
1016 			for (i = 0; i < xfer_size; i++)
1017 				if (put_user(0xffU, (u8 __user *)codes + i))
1018 					return -EFAULT;
1019 		}
1020 	}
1021 
1022 	if (xfer_size < codes_size)
1023 		if (clear_user(codes + xfer_size, codes_size - xfer_size))
1024 			return -EFAULT;
1025 
1026 	return 0;
1027 }
1028 
evdev_do_ioctl(struct file * file,unsigned int cmd,void __user * p,int compat_mode)1029 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
1030 			   void __user *p, int compat_mode)
1031 {
1032 	struct evdev_client *client = file->private_data;
1033 	struct evdev *evdev = client->evdev;
1034 	struct input_dev *dev = evdev->handle.dev;
1035 	struct input_absinfo abs;
1036 	struct input_mask mask;
1037 	struct ff_effect effect;
1038 	int __user *ip = (int __user *)p;
1039 	unsigned int i, t, u, v;
1040 	unsigned int size;
1041 	int error;
1042 
1043 	/* First we check for fixed-length commands */
1044 	switch (cmd) {
1045 
1046 	case EVIOCGVERSION:
1047 		return put_user(EV_VERSION, ip);
1048 
1049 	case EVIOCGID:
1050 		if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
1051 			return -EFAULT;
1052 		return 0;
1053 
1054 	case EVIOCGREP:
1055 		if (!test_bit(EV_REP, dev->evbit))
1056 			return -ENOSYS;
1057 		if (put_user(dev->rep[REP_DELAY], ip))
1058 			return -EFAULT;
1059 		if (put_user(dev->rep[REP_PERIOD], ip + 1))
1060 			return -EFAULT;
1061 		return 0;
1062 
1063 	case EVIOCSREP:
1064 		if (!test_bit(EV_REP, dev->evbit))
1065 			return -ENOSYS;
1066 		if (get_user(u, ip))
1067 			return -EFAULT;
1068 		if (get_user(v, ip + 1))
1069 			return -EFAULT;
1070 
1071 		input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
1072 		input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
1073 
1074 		return 0;
1075 
1076 	case EVIOCRMFF:
1077 		return input_ff_erase(dev, (int)(unsigned long) p, file);
1078 
1079 	case EVIOCGEFFECTS:
1080 		i = test_bit(EV_FF, dev->evbit) ?
1081 				dev->ff->max_effects : 0;
1082 		if (put_user(i, ip))
1083 			return -EFAULT;
1084 		return 0;
1085 
1086 	case EVIOCGRAB:
1087 		if (p)
1088 			return evdev_grab(evdev, client);
1089 		else
1090 			return evdev_ungrab(evdev, client);
1091 
1092 	case EVIOCREVOKE:
1093 		if (p)
1094 			return -EINVAL;
1095 		else
1096 			return evdev_revoke(evdev, client, file);
1097 
1098 	case EVIOCGMASK: {
1099 		void __user *codes_ptr;
1100 
1101 		if (copy_from_user(&mask, p, sizeof(mask)))
1102 			return -EFAULT;
1103 
1104 		codes_ptr = (void __user *)(unsigned long)mask.codes_ptr;
1105 		return evdev_get_mask(client,
1106 				      mask.type, codes_ptr, mask.codes_size,
1107 				      compat_mode);
1108 	}
1109 
1110 	case EVIOCSMASK: {
1111 		const void __user *codes_ptr;
1112 
1113 		if (copy_from_user(&mask, p, sizeof(mask)))
1114 			return -EFAULT;
1115 
1116 		codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr;
1117 		return evdev_set_mask(client,
1118 				      mask.type, codes_ptr, mask.codes_size,
1119 				      compat_mode);
1120 	}
1121 
1122 	case EVIOCSCLOCKID:
1123 		if (copy_from_user(&i, p, sizeof(unsigned int)))
1124 			return -EFAULT;
1125 
1126 		return evdev_set_clk_type(client, i);
1127 
1128 	case EVIOCGKEYCODE:
1129 		return evdev_handle_get_keycode(dev, p);
1130 
1131 	case EVIOCSKEYCODE:
1132 		return evdev_handle_set_keycode(dev, p);
1133 
1134 	case EVIOCGKEYCODE_V2:
1135 		return evdev_handle_get_keycode_v2(dev, p);
1136 
1137 	case EVIOCSKEYCODE_V2:
1138 		return evdev_handle_set_keycode_v2(dev, p);
1139 	}
1140 
1141 	size = _IOC_SIZE(cmd);
1142 
1143 	/* Now check variable-length commands */
1144 #define EVIOC_MASK_SIZE(nr)	((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
1145 	switch (EVIOC_MASK_SIZE(cmd)) {
1146 
1147 	case EVIOCGPROP(0):
1148 		return bits_to_user(dev->propbit, INPUT_PROP_MAX,
1149 				    size, p, compat_mode);
1150 
1151 	case EVIOCGMTSLOTS(0):
1152 		return evdev_handle_mt_request(dev, size, ip);
1153 
1154 	case EVIOCGKEY(0):
1155 		return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
1156 					    KEY_MAX, size, p, compat_mode);
1157 
1158 	case EVIOCGLED(0):
1159 		return evdev_handle_get_val(client, dev, EV_LED, dev->led,
1160 					    LED_MAX, size, p, compat_mode);
1161 
1162 	case EVIOCGSND(0):
1163 		return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
1164 					    SND_MAX, size, p, compat_mode);
1165 
1166 	case EVIOCGSW(0):
1167 		return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
1168 					    SW_MAX, size, p, compat_mode);
1169 
1170 	case EVIOCGNAME(0):
1171 		return str_to_user(dev->name, size, p);
1172 
1173 	case EVIOCGPHYS(0):
1174 		return str_to_user(dev->phys, size, p);
1175 
1176 	case EVIOCGUNIQ(0):
1177 		return str_to_user(dev->uniq, size, p);
1178 
1179 	case EVIOC_MASK_SIZE(EVIOCSFF):
1180 		if (input_ff_effect_from_user(p, size, &effect))
1181 			return -EFAULT;
1182 
1183 		error = input_ff_upload(dev, &effect, file);
1184 		if (error)
1185 			return error;
1186 
1187 		if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
1188 			return -EFAULT;
1189 
1190 		return 0;
1191 	}
1192 
1193 	/* Multi-number variable-length handlers */
1194 	if (_IOC_TYPE(cmd) != 'E')
1195 		return -EINVAL;
1196 
1197 	if (_IOC_DIR(cmd) == _IOC_READ) {
1198 
1199 		if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
1200 			return handle_eviocgbit(dev,
1201 						_IOC_NR(cmd) & EV_MAX, size,
1202 						p, compat_mode);
1203 
1204 		if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1205 
1206 			if (!dev->absinfo)
1207 				return -EINVAL;
1208 
1209 			t = _IOC_NR(cmd) & ABS_MAX;
1210 			abs = dev->absinfo[t];
1211 
1212 			if (copy_to_user(p, &abs, min_t(size_t,
1213 					size, sizeof(struct input_absinfo))))
1214 				return -EFAULT;
1215 
1216 			return 0;
1217 		}
1218 	}
1219 
1220 	if (_IOC_DIR(cmd) == _IOC_WRITE) {
1221 
1222 		if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1223 
1224 			if (!dev->absinfo)
1225 				return -EINVAL;
1226 
1227 			t = _IOC_NR(cmd) & ABS_MAX;
1228 
1229 			if (copy_from_user(&abs, p, min_t(size_t,
1230 					size, sizeof(struct input_absinfo))))
1231 				return -EFAULT;
1232 
1233 			if (size < sizeof(struct input_absinfo))
1234 				abs.resolution = 0;
1235 
1236 			/* We can't change number of reserved MT slots */
1237 			if (t == ABS_MT_SLOT)
1238 				return -EINVAL;
1239 
1240 			/*
1241 			 * Take event lock to ensure that we are not
1242 			 * changing device parameters in the middle
1243 			 * of event.
1244 			 */
1245 			spin_lock_irq(&dev->event_lock);
1246 			dev->absinfo[t] = abs;
1247 			spin_unlock_irq(&dev->event_lock);
1248 
1249 			return 0;
1250 		}
1251 	}
1252 
1253 	return -EINVAL;
1254 }
1255 
evdev_ioctl_handler(struct file * file,unsigned int cmd,void __user * p,int compat_mode)1256 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1257 				void __user *p, int compat_mode)
1258 {
1259 	struct evdev_client *client = file->private_data;
1260 	struct evdev *evdev = client->evdev;
1261 	int retval;
1262 
1263 	retval = mutex_lock_interruptible(&evdev->mutex);
1264 	if (retval)
1265 		return retval;
1266 
1267 	if (!evdev->exist || client->revoked) {
1268 		retval = -ENODEV;
1269 		goto out;
1270 	}
1271 
1272 	retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1273 
1274  out:
1275 	mutex_unlock(&evdev->mutex);
1276 	return retval;
1277 }
1278 
evdev_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1279 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1280 {
1281 	return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1282 }
1283 
1284 #ifdef CONFIG_COMPAT
evdev_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)1285 static long evdev_ioctl_compat(struct file *file,
1286 				unsigned int cmd, unsigned long arg)
1287 {
1288 	return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1289 }
1290 #endif
1291 
1292 static const struct file_operations evdev_fops = {
1293 	.owner		= THIS_MODULE,
1294 	.read		= evdev_read,
1295 	.write		= evdev_write,
1296 	.poll		= evdev_poll,
1297 	.open		= evdev_open,
1298 	.release	= evdev_release,
1299 	.unlocked_ioctl	= evdev_ioctl,
1300 #ifdef CONFIG_COMPAT
1301 	.compat_ioctl	= evdev_ioctl_compat,
1302 #endif
1303 	.fasync		= evdev_fasync,
1304 	.llseek		= no_llseek,
1305 };
1306 
1307 /*
1308  * Mark device non-existent. This disables writes, ioctls and
1309  * prevents new users from opening the device. Already posted
1310  * blocking reads will stay, however new ones will fail.
1311  */
evdev_mark_dead(struct evdev * evdev)1312 static void evdev_mark_dead(struct evdev *evdev)
1313 {
1314 	mutex_lock(&evdev->mutex);
1315 	evdev->exist = false;
1316 	mutex_unlock(&evdev->mutex);
1317 }
1318 
evdev_cleanup(struct evdev * evdev)1319 static void evdev_cleanup(struct evdev *evdev)
1320 {
1321 	struct input_handle *handle = &evdev->handle;
1322 
1323 	evdev_mark_dead(evdev);
1324 	evdev_hangup(evdev);
1325 
1326 	/* evdev is marked dead so no one else accesses evdev->open */
1327 	if (evdev->open) {
1328 		input_flush_device(handle, NULL);
1329 		input_close_device(handle);
1330 	}
1331 }
1332 
1333 /*
1334  * Create new evdev device. Note that input core serializes calls
1335  * to connect and disconnect.
1336  */
evdev_connect(struct input_handler * handler,struct input_dev * dev,const struct input_device_id * id)1337 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1338 			 const struct input_device_id *id)
1339 {
1340 	struct evdev *evdev;
1341 	int minor;
1342 	int dev_no;
1343 	int error;
1344 
1345 	minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1346 	if (minor < 0) {
1347 		error = minor;
1348 		pr_err("failed to reserve new minor: %d\n", error);
1349 		return error;
1350 	}
1351 
1352 	evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1353 	if (!evdev) {
1354 		error = -ENOMEM;
1355 		goto err_free_minor;
1356 	}
1357 
1358 	INIT_LIST_HEAD(&evdev->client_list);
1359 	spin_lock_init(&evdev->client_lock);
1360 	mutex_init(&evdev->mutex);
1361 	evdev->exist = true;
1362 
1363 	dev_no = minor;
1364 	/* Normalize device number if it falls into legacy range */
1365 	if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1366 		dev_no -= EVDEV_MINOR_BASE;
1367 	dev_set_name(&evdev->dev, "event%d", dev_no);
1368 
1369 	evdev->handle.dev = input_get_device(dev);
1370 	evdev->handle.name = dev_name(&evdev->dev);
1371 	evdev->handle.handler = handler;
1372 	evdev->handle.private = evdev;
1373 
1374 	evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1375 	evdev->dev.class = &input_class;
1376 	evdev->dev.parent = &dev->dev;
1377 	evdev->dev.release = evdev_free;
1378 	device_initialize(&evdev->dev);
1379 
1380 	error = input_register_handle(&evdev->handle);
1381 	if (error)
1382 		goto err_free_evdev;
1383 
1384 	cdev_init(&evdev->cdev, &evdev_fops);
1385 
1386 	error = cdev_device_add(&evdev->cdev, &evdev->dev);
1387 	if (error)
1388 		goto err_cleanup_evdev;
1389 
1390 	return 0;
1391 
1392  err_cleanup_evdev:
1393 	evdev_cleanup(evdev);
1394 	input_unregister_handle(&evdev->handle);
1395  err_free_evdev:
1396 	put_device(&evdev->dev);
1397  err_free_minor:
1398 	input_free_minor(minor);
1399 	return error;
1400 }
1401 
evdev_disconnect(struct input_handle * handle)1402 static void evdev_disconnect(struct input_handle *handle)
1403 {
1404 	struct evdev *evdev = handle->private;
1405 
1406 	cdev_device_del(&evdev->cdev, &evdev->dev);
1407 	evdev_cleanup(evdev);
1408 	input_free_minor(MINOR(evdev->dev.devt));
1409 	input_unregister_handle(handle);
1410 	put_device(&evdev->dev);
1411 }
1412 
1413 static const struct input_device_id evdev_ids[] = {
1414 	{ .driver_info = 1 },	/* Matches all devices */
1415 	{ },			/* Terminating zero entry */
1416 };
1417 
1418 MODULE_DEVICE_TABLE(input, evdev_ids);
1419 
1420 static struct input_handler evdev_handler = {
1421 	.event		= evdev_event,
1422 	.events		= evdev_events,
1423 	.connect	= evdev_connect,
1424 	.disconnect	= evdev_disconnect,
1425 	.legacy_minors	= true,
1426 	.minor		= EVDEV_MINOR_BASE,
1427 	.name		= "evdev",
1428 	.id_table	= evdev_ids,
1429 };
1430 
evdev_init(void)1431 static int __init evdev_init(void)
1432 {
1433 	return input_register_handler(&evdev_handler);
1434 }
1435 
evdev_exit(void)1436 static void __exit evdev_exit(void)
1437 {
1438 	input_unregister_handler(&evdev_handler);
1439 }
1440 
1441 module_init(evdev_init);
1442 module_exit(evdev_exit);
1443 
1444 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1445 MODULE_DESCRIPTION("Input driver event char devices");
1446 MODULE_LICENSE("GPL");
1447