projects/linux·blob v5.6 · refs

1457 lines · 32.6 KiB

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
28struct evdev {
29 int open;
30 struct input_handle handle;
31 wait_queue_head_t wait;
32 struct evdev_client __rcu *grab;
33 struct list_head client_list;
34 spinlock_t client_lock; /* protects client_list */
35 struct mutex mutex;
36 struct device dev;
37 struct cdev cdev;
38 bool exist;
39};
40
41struct evdev_client {
42 unsigned int head;
43 unsigned int tail;
44 unsigned int packet_head; /* [future] position of the first element of next packet */
45 spinlock_t buffer_lock; /* protects access to buffer, head and tail */
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
56static 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 */
75static 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 */
101static 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
143static 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
165static 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
174static 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
214static 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
244static void evdev_pass_values(struct evdev_client *client,
245 const struct input_value *vals, unsigned int count,
246 ktime_t *ev_time)
247{
248 struct evdev *evdev = client->evdev;
249 const struct input_value *v;
250 struct input_event event;
251 struct timespec64 ts;
252 bool wakeup = false;
253
254 if (client->revoked)
255 return;
256
257 ts = ktime_to_timespec64(ev_time[client->clk_type]);
258 event.input_event_sec = ts.tv_sec;
259 event.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
260
261 /* Interrupts are disabled, just acquire the lock. */
262 spin_lock(&client->buffer_lock);
263
264 for (v = vals; v != vals + count; v++) {
265 if (__evdev_is_filtered(client, v->type, v->code))
266 continue;
267
268 if (v->type == EV_SYN && v->code == SYN_REPORT) {
269 /* drop empty SYN_REPORT */
270 if (client->packet_head == client->head)
271 continue;
272
273 wakeup = true;
274 }
275
276 event.type = v->type;
277 event.code = v->code;
278 event.value = v->value;
279 __pass_event(client, &event);
280 }
281
282 spin_unlock(&client->buffer_lock);
283
284 if (wakeup)
285 wake_up_interruptible(&evdev->wait);
286}
287
288/*
289 * Pass incoming events to all connected clients.
290 */
291static 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 */
314static 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
322static 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
329static int evdev_flush(struct file *file, fl_owner_t id)
330{
331 struct evdev_client *client = file->private_data;
332 struct evdev *evdev = client->evdev;
333
334 mutex_lock(&evdev->mutex);
335
336 if (evdev->exist && !client->revoked)
337 input_flush_device(&evdev->handle, file);
338
339 mutex_unlock(&evdev->mutex);
340 return 0;
341}
342
343static void evdev_free(struct device *dev)
344{
345 struct evdev *evdev = container_of(dev, struct evdev, dev);
346
347 input_put_device(evdev->handle.dev);
348 kfree(evdev);
349}
350
351/*
352 * Grabs an event device (along with underlying input device).
353 * This function is called with evdev->mutex taken.
354 */
355static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
356{
357 int error;
358
359 if (evdev->grab)
360 return -EBUSY;
361
362 error = input_grab_device(&evdev->handle);
363 if (error)
364 return error;
365
366 rcu_assign_pointer(evdev->grab, client);
367
368 return 0;
369}
370
371static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
372{
373 struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
374 lockdep_is_held(&evdev->mutex));
375
376 if (grab != client)
377 return -EINVAL;
378
379 rcu_assign_pointer(evdev->grab, NULL);
380 synchronize_rcu();
381 input_release_device(&evdev->handle);
382
383 return 0;
384}
385
386static void evdev_attach_client(struct evdev *evdev,
387 struct evdev_client *client)
388{
389 spin_lock(&evdev->client_lock);
390 list_add_tail_rcu(&client->node, &evdev->client_list);
391 spin_unlock(&evdev->client_lock);
392}
393
394static void evdev_detach_client(struct evdev *evdev,
395 struct evdev_client *client)
396{
397 spin_lock(&evdev->client_lock);
398 list_del_rcu(&client->node);
399 spin_unlock(&evdev->client_lock);
400 synchronize_rcu();
401}
402
403static int evdev_open_device(struct evdev *evdev)
404{
405 int retval;
406
407 retval = mutex_lock_interruptible(&evdev->mutex);
408 if (retval)
409 return retval;
410
411 if (!evdev->exist)
412 retval = -ENODEV;
413 else if (!evdev->open++) {
414 retval = input_open_device(&evdev->handle);
415 if (retval)
416 evdev->open--;
417 }
418
419 mutex_unlock(&evdev->mutex);
420 return retval;
421}
422
423static void evdev_close_device(struct evdev *evdev)
424{
425 mutex_lock(&evdev->mutex);
426
427 if (evdev->exist && !--evdev->open)
428 input_close_device(&evdev->handle);
429
430 mutex_unlock(&evdev->mutex);
431}
432
433/*
434 * Wake up users waiting for IO so they can disconnect from
435 * dead device.
436 */
437static void evdev_hangup(struct evdev *evdev)
438{
439 struct evdev_client *client;
440
441 spin_lock(&evdev->client_lock);
442 list_for_each_entry(client, &evdev->client_list, node)
443 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
444 spin_unlock(&evdev->client_lock);
445
446 wake_up_interruptible(&evdev->wait);
447}
448
449static int evdev_release(struct inode *inode, struct file *file)
450{
451 struct evdev_client *client = file->private_data;
452 struct evdev *evdev = client->evdev;
453 unsigned int i;
454
455 mutex_lock(&evdev->mutex);
456 evdev_ungrab(evdev, client);
457 mutex_unlock(&evdev->mutex);
458
459 evdev_detach_client(evdev, client);
460
461 for (i = 0; i < EV_CNT; ++i)
462 bitmap_free(client->evmasks[i]);
463
464 kvfree(client);
465
466 evdev_close_device(evdev);
467
468 return 0;
469}
470
471static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
472{
473 unsigned int n_events =
474 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
475 EVDEV_MIN_BUFFER_SIZE);
476
477 return roundup_pow_of_two(n_events);
478}
479
480static int evdev_open(struct inode *inode, struct file *file)
481{
482 struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
483 unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
484 struct evdev_client *client;
485 int error;
486
487 client = kvzalloc(struct_size(client, buffer, bufsize), GFP_KERNEL);
488 if (!client)
489 return -ENOMEM;
490
491 client->bufsize = bufsize;
492 spin_lock_init(&client->buffer_lock);
493 client->evdev = evdev;
494 evdev_attach_client(evdev, client);
495
496 error = evdev_open_device(evdev);
497 if (error)
498 goto err_free_client;
499
500 file->private_data = client;
501 stream_open(inode, file);
502
503 return 0;
504
505 err_free_client:
506 evdev_detach_client(evdev, client);
507 kvfree(client);
508 return error;
509}
510
511static ssize_t evdev_write(struct file *file, const char __user *buffer,
512 size_t count, loff_t *ppos)
513{
514 struct evdev_client *client = file->private_data;
515 struct evdev *evdev = client->evdev;
516 struct input_event event;
517 int retval = 0;
518
519 if (count != 0 && count < input_event_size())
520 return -EINVAL;
521
522 retval = mutex_lock_interruptible(&evdev->mutex);
523 if (retval)
524 return retval;
525
526 if (!evdev->exist || client->revoked) {
527 retval = -ENODEV;
528 goto out;
529 }
530
531 while (retval + input_event_size() <= count) {
532
533 if (input_event_from_user(buffer + retval, &event)) {
534 retval = -EFAULT;
535 goto out;
536 }
537 retval += input_event_size();
538
539 input_inject_event(&evdev->handle,
540 event.type, event.code, event.value);
541 cond_resched();
542 }
543
544 out:
545 mutex_unlock(&evdev->mutex);
546 return retval;
547}
548
549static int evdev_fetch_next_event(struct evdev_client *client,
550 struct input_event *event)
551{
552 int have_event;
553
554 spin_lock_irq(&client->buffer_lock);
555
556 have_event = client->packet_head != client->tail;
557 if (have_event) {
558 *event = client->buffer[client->tail++];
559 client->tail &= client->bufsize - 1;
560 }
561
562 spin_unlock_irq(&client->buffer_lock);
563
564 return have_event;
565}
566
567static ssize_t evdev_read(struct file *file, char __user *buffer,
568 size_t count, loff_t *ppos)
569{
570 struct evdev_client *client = file->private_data;
571 struct evdev *evdev = client->evdev;
572 struct input_event event;
573 size_t read = 0;
574 int error;
575
576 if (count != 0 && count < input_event_size())
577 return -EINVAL;
578
579 for (;;) {
580 if (!evdev->exist || client->revoked)
581 return -ENODEV;
582
583 if (client->packet_head == client->tail &&
584 (file->f_flags & O_NONBLOCK))
585 return -EAGAIN;
586
587 /*
588 * count == 0 is special - no IO is done but we check
589 * for error conditions (see above).
590 */
591 if (count == 0)
592 break;
593
594 while (read + input_event_size() <= count &&
595 evdev_fetch_next_event(client, &event)) {
596
597 if (input_event_to_user(buffer + read, &event))
598 return -EFAULT;
599
600 read += input_event_size();
601 }
602
603 if (read)
604 break;
605
606 if (!(file->f_flags & O_NONBLOCK)) {
607 error = wait_event_interruptible(evdev->wait,
608 client->packet_head != client->tail ||
609 !evdev->exist || client->revoked);
610 if (error)
611 return error;
612 }
613 }
614
615 return read;
616}
617
618/* No kernel lock - fine */
619static __poll_t evdev_poll(struct file *file, poll_table *wait)
620{
621 struct evdev_client *client = file->private_data;
622 struct evdev *evdev = client->evdev;
623 __poll_t mask;
624
625 poll_wait(file, &evdev->wait, wait);
626
627 if (evdev->exist && !client->revoked)
628 mask = EPOLLOUT | EPOLLWRNORM;
629 else
630 mask = EPOLLHUP | EPOLLERR;
631
632 if (client->packet_head != client->tail)
633 mask |= EPOLLIN | EPOLLRDNORM;
634
635 return mask;
636}
637
638#ifdef CONFIG_COMPAT
639
640#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
641#define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
642
643#ifdef __BIG_ENDIAN
644static int bits_to_user(unsigned long *bits, unsigned int maxbit,
645 unsigned int maxlen, void __user *p, int compat)
646{
647 int len, i;
648
649 if (compat) {
650 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
651 if (len > maxlen)
652 len = maxlen;
653
654 for (i = 0; i < len / sizeof(compat_long_t); i++)
655 if (copy_to_user((compat_long_t __user *) p + i,
656 (compat_long_t *) bits +
657 i + 1 - ((i % 2) << 1),
658 sizeof(compat_long_t)))
659 return -EFAULT;
660 } else {
661 len = BITS_TO_LONGS(maxbit) * sizeof(long);
662 if (len > maxlen)
663 len = maxlen;
664
665 if (copy_to_user(p, bits, len))
666 return -EFAULT;
667 }
668
669 return len;
670}
671
672static int bits_from_user(unsigned long *bits, unsigned int maxbit,
673 unsigned int maxlen, const void __user *p, int compat)
674{
675 int len, i;
676
677 if (compat) {
678 if (maxlen % sizeof(compat_long_t))
679 return -EINVAL;
680
681 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
682 if (len > maxlen)
683 len = maxlen;
684
685 for (i = 0; i < len / sizeof(compat_long_t); i++)
686 if (copy_from_user((compat_long_t *) bits +
687 i + 1 - ((i % 2) << 1),
688 (compat_long_t __user *) p + i,
689 sizeof(compat_long_t)))
690 return -EFAULT;
691 if (i % 2)
692 *((compat_long_t *) bits + i - 1) = 0;
693
694 } else {
695 if (maxlen % sizeof(long))
696 return -EINVAL;
697
698 len = BITS_TO_LONGS(maxbit) * sizeof(long);
699 if (len > maxlen)
700 len = maxlen;
701
702 if (copy_from_user(bits, p, len))
703 return -EFAULT;
704 }
705
706 return len;
707}
708
709#else
710
711static int bits_to_user(unsigned long *bits, unsigned int maxbit,
712 unsigned int maxlen, void __user *p, int compat)
713{
714 int len = compat ?
715 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
716 BITS_TO_LONGS(maxbit) * sizeof(long);
717
718 if (len > maxlen)
719 len = maxlen;
720
721 return copy_to_user(p, bits, len) ? -EFAULT : len;
722}
723
724static int bits_from_user(unsigned long *bits, unsigned int maxbit,
725 unsigned int maxlen, const void __user *p, int compat)
726{
727 size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long);
728 int len;
729
730 if (maxlen % chunk_size)
731 return -EINVAL;
732
733 len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);
734 len *= chunk_size;
735 if (len > maxlen)
736 len = maxlen;
737
738 return copy_from_user(bits, p, len) ? -EFAULT : len;
739}
740
741#endif /* __BIG_ENDIAN */
742
743#else
744
745static int bits_to_user(unsigned long *bits, unsigned int maxbit,
746 unsigned int maxlen, void __user *p, int compat)
747{
748 int len = BITS_TO_LONGS(maxbit) * sizeof(long);
749
750 if (len > maxlen)
751 len = maxlen;
752
753 return copy_to_user(p, bits, len) ? -EFAULT : len;
754}
755
756static int bits_from_user(unsigned long *bits, unsigned int maxbit,
757 unsigned int maxlen, const void __user *p, int compat)
758{
759 int len;
760
761 if (maxlen % sizeof(long))
762 return -EINVAL;
763
764 len = BITS_TO_LONGS(maxbit) * sizeof(long);
765 if (len > maxlen)
766 len = maxlen;
767
768 return copy_from_user(bits, p, len) ? -EFAULT : len;
769}
770
771#endif /* CONFIG_COMPAT */
772
773static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
774{
775 int len;
776
777 if (!str)
778 return -ENOENT;
779
780 len = strlen(str) + 1;
781 if (len > maxlen)
782 len = maxlen;
783
784 return copy_to_user(p, str, len) ? -EFAULT : len;
785}
786
787static int handle_eviocgbit(struct input_dev *dev,
788 unsigned int type, unsigned int size,
789 void __user *p, int compat_mode)
790{
791 unsigned long *bits;
792 int len;
793
794 switch (type) {
795
796 case 0: bits = dev->evbit; len = EV_MAX; break;
797 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
798 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
799 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
800 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
801 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
802 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
803 case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
804 case EV_SW: bits = dev->swbit; len = SW_MAX; break;
805 default: return -EINVAL;
806 }
807
808 return bits_to_user(bits, len, size, p, compat_mode);
809}
810
811static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
812{
813 struct input_keymap_entry ke = {
814 .len = sizeof(unsigned int),
815 .flags = 0,
816 };
817 int __user *ip = (int __user *)p;
818 int error;
819
820 /* legacy case */
821 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
822 return -EFAULT;
823
824 error = input_get_keycode(dev, &ke);
825 if (error)
826 return error;
827
828 if (put_user(ke.keycode, ip + 1))
829 return -EFAULT;
830
831 return 0;
832}
833
834static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
835{
836 struct input_keymap_entry ke;
837 int error;
838
839 if (copy_from_user(&ke, p, sizeof(ke)))
840 return -EFAULT;
841
842 error = input_get_keycode(dev, &ke);
843 if (error)
844 return error;
845
846 if (copy_to_user(p, &ke, sizeof(ke)))
847 return -EFAULT;
848
849 return 0;
850}
851
852static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
853{
854 struct input_keymap_entry ke = {
855 .len = sizeof(unsigned int),
856 .flags = 0,
857 };
858 int __user *ip = (int __user *)p;
859
860 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
861 return -EFAULT;
862
863 if (get_user(ke.keycode, ip + 1))
864 return -EFAULT;
865
866 return input_set_keycode(dev, &ke);
867}
868
869static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
870{
871 struct input_keymap_entry ke;
872
873 if (copy_from_user(&ke, p, sizeof(ke)))
874 return -EFAULT;
875
876 if (ke.len > sizeof(ke.scancode))
877 return -EINVAL;
878
879 return input_set_keycode(dev, &ke);
880}
881
882/*
883 * If we transfer state to the user, we should flush all pending events
884 * of the same type from the client's queue. Otherwise, they might end up
885 * with duplicate events, which can screw up client's state tracking.
886 * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
887 * event so user-space will notice missing events.
888 *
889 * LOCKING:
890 * We need to take event_lock before buffer_lock to avoid dead-locks. But we
891 * need the even_lock only to guarantee consistent state. We can safely release
892 * it while flushing the queue. This allows input-core to handle filters while
893 * we flush the queue.
894 */
895static int evdev_handle_get_val(struct evdev_client *client,
896 struct input_dev *dev, unsigned int type,
897 unsigned long *bits, unsigned int maxbit,
898 unsigned int maxlen, void __user *p,
899 int compat)
900{
901 int ret;
902 unsigned long *mem;
903
904 mem = bitmap_alloc(maxbit, GFP_KERNEL);
905 if (!mem)
906 return -ENOMEM;
907
908 spin_lock_irq(&dev->event_lock);
909 spin_lock(&client->buffer_lock);
910
911 bitmap_copy(mem, bits, maxbit);
912
913 spin_unlock(&dev->event_lock);
914
915 __evdev_flush_queue(client, type);
916
917 spin_unlock_irq(&client->buffer_lock);
918
919 ret = bits_to_user(mem, maxbit, maxlen, p, compat);
920 if (ret < 0)
921 evdev_queue_syn_dropped(client);
922
923 bitmap_free(mem);
924
925 return ret;
926}
927
928static int evdev_handle_mt_request(struct input_dev *dev,
929 unsigned int size,
930 int __user *ip)
931{
932 const struct input_mt *mt = dev->mt;
933 unsigned int code;
934 int max_slots;
935 int i;
936
937 if (get_user(code, &ip[0]))
938 return -EFAULT;
939 if (!mt || !input_is_mt_value(code))
940 return -EINVAL;
941
942 max_slots = (size - sizeof(__u32)) / sizeof(__s32);
943 for (i = 0; i < mt->num_slots && i < max_slots; i++) {
944 int value = input_mt_get_value(&mt->slots[i], code);
945 if (put_user(value, &ip[1 + i]))
946 return -EFAULT;
947 }
948
949 return 0;
950}
951
952static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
953 struct file *file)
954{
955 client->revoked = true;
956 evdev_ungrab(evdev, client);
957 input_flush_device(&evdev->handle, file);
958 wake_up_interruptible(&evdev->wait);
959
960 return 0;
961}
962
963/* must be called with evdev-mutex held */
964static int evdev_set_mask(struct evdev_client *client,
965 unsigned int type,
966 const void __user *codes,
967 u32 codes_size,
968 int compat)
969{
970 unsigned long flags, *mask, *oldmask;
971 size_t cnt;
972 int error;
973
974 /* we allow unknown types and 'codes_size > size' for forward-compat */
975 cnt = evdev_get_mask_cnt(type);
976 if (!cnt)
977 return 0;
978
979 mask = bitmap_zalloc(cnt, GFP_KERNEL);
980 if (!mask)
981 return -ENOMEM;
982
983 error = bits_from_user(mask, cnt - 1, codes_size, codes, compat);
984 if (error < 0) {
985 bitmap_free(mask);
986 return error;
987 }
988
989 spin_lock_irqsave(&client->buffer_lock, flags);
990 oldmask = client->evmasks[type];
991 client->evmasks[type] = mask;
992 spin_unlock_irqrestore(&client->buffer_lock, flags);
993
994 bitmap_free(oldmask);
995
996 return 0;
997}
998
999/* must be called with evdev-mutex held */
1000static int evdev_get_mask(struct evdev_client *client,
1001 unsigned int type,
1002 void __user *codes,
1003 u32 codes_size,
1004 int compat)
1005{
1006 unsigned long *mask;
1007 size_t cnt, size, xfer_size;
1008 int i;
1009 int error;
1010
1011 /* we allow unknown types and 'codes_size > size' for forward-compat */
1012 cnt = evdev_get_mask_cnt(type);
1013 size = sizeof(unsigned long) * BITS_TO_LONGS(cnt);
1014 xfer_size = min_t(size_t, codes_size, size);
1015
1016 if (cnt > 0) {
1017 mask = client->evmasks[type];
1018 if (mask) {
1019 error = bits_to_user(mask, cnt - 1,
1020 xfer_size, codes, compat);
1021 if (error < 0)
1022 return error;
1023 } else {
1024 /* fake mask with all bits set */
1025 for (i = 0; i < xfer_size; i++)
1026 if (put_user(0xffU, (u8 __user *)codes + i))
1027 return -EFAULT;
1028 }
1029 }
1030
1031 if (xfer_size < codes_size)
1032 if (clear_user(codes + xfer_size, codes_size - xfer_size))
1033 return -EFAULT;
1034
1035 return 0;
1036}
1037
1038static long evdev_do_ioctl(struct file *file, unsigned int cmd,
1039 void __user *p, int compat_mode)
1040{
1041 struct evdev_client *client = file->private_data;
1042 struct evdev *evdev = client->evdev;
1043 struct input_dev *dev = evdev->handle.dev;
1044 struct input_absinfo abs;
1045 struct input_mask mask;
1046 struct ff_effect effect;
1047 int __user *ip = (int __user *)p;
1048 unsigned int i, t, u, v;
1049 unsigned int size;
1050 int error;
1051
1052 /* First we check for fixed-length commands */
1053 switch (cmd) {
1054
1055 case EVIOCGVERSION:
1056 return put_user(EV_VERSION, ip);
1057
1058 case EVIOCGID:
1059 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
1060 return -EFAULT;
1061 return 0;
1062
1063 case EVIOCGREP:
1064 if (!test_bit(EV_REP, dev->evbit))
1065 return -ENOSYS;
1066 if (put_user(dev->rep[REP_DELAY], ip))
1067 return -EFAULT;
1068 if (put_user(dev->rep[REP_PERIOD], ip + 1))
1069 return -EFAULT;
1070 return 0;
1071
1072 case EVIOCSREP:
1073 if (!test_bit(EV_REP, dev->evbit))
1074 return -ENOSYS;
1075 if (get_user(u, ip))
1076 return -EFAULT;
1077 if (get_user(v, ip + 1))
1078 return -EFAULT;
1079
1080 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
1081 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
1082
1083 return 0;
1084
1085 case EVIOCRMFF:
1086 return input_ff_erase(dev, (int)(unsigned long) p, file);
1087
1088 case EVIOCGEFFECTS:
1089 i = test_bit(EV_FF, dev->evbit) ?
1090 dev->ff->max_effects : 0;
1091 if (put_user(i, ip))
1092 return -EFAULT;
1093 return 0;
1094
1095 case EVIOCGRAB:
1096 if (p)
1097 return evdev_grab(evdev, client);
1098 else
1099 return evdev_ungrab(evdev, client);
1100
1101 case EVIOCREVOKE:
1102 if (p)
1103 return -EINVAL;
1104 else
1105 return evdev_revoke(evdev, client, file);
1106
1107 case EVIOCGMASK: {
1108 void __user *codes_ptr;
1109
1110 if (copy_from_user(&mask, p, sizeof(mask)))
1111 return -EFAULT;
1112
1113 codes_ptr = (void __user *)(unsigned long)mask.codes_ptr;
1114 return evdev_get_mask(client,
1115 mask.type, codes_ptr, mask.codes_size,
1116 compat_mode);
1117 }
1118
1119 case EVIOCSMASK: {
1120 const void __user *codes_ptr;
1121
1122 if (copy_from_user(&mask, p, sizeof(mask)))
1123 return -EFAULT;
1124
1125 codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr;
1126 return evdev_set_mask(client,
1127 mask.type, codes_ptr, mask.codes_size,
1128 compat_mode);
1129 }
1130
1131 case EVIOCSCLOCKID:
1132 if (copy_from_user(&i, p, sizeof(unsigned int)))
1133 return -EFAULT;
1134
1135 return evdev_set_clk_type(client, i);
1136
1137 case EVIOCGKEYCODE:
1138 return evdev_handle_get_keycode(dev, p);
1139
1140 case EVIOCSKEYCODE:
1141 return evdev_handle_set_keycode(dev, p);
1142
1143 case EVIOCGKEYCODE_V2:
1144 return evdev_handle_get_keycode_v2(dev, p);
1145
1146 case EVIOCSKEYCODE_V2:
1147 return evdev_handle_set_keycode_v2(dev, p);
1148 }
1149
1150 size = _IOC_SIZE(cmd);
1151
1152 /* Now check variable-length commands */
1153#define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
1154 switch (EVIOC_MASK_SIZE(cmd)) {
1155
1156 case EVIOCGPROP(0):
1157 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
1158 size, p, compat_mode);
1159
1160 case EVIOCGMTSLOTS(0):
1161 return evdev_handle_mt_request(dev, size, ip);
1162
1163 case EVIOCGKEY(0):
1164 return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
1165 KEY_MAX, size, p, compat_mode);
1166
1167 case EVIOCGLED(0):
1168 return evdev_handle_get_val(client, dev, EV_LED, dev->led,
1169 LED_MAX, size, p, compat_mode);
1170
1171 case EVIOCGSND(0):
1172 return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
1173 SND_MAX, size, p, compat_mode);
1174
1175 case EVIOCGSW(0):
1176 return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
1177 SW_MAX, size, p, compat_mode);
1178
1179 case EVIOCGNAME(0):
1180 return str_to_user(dev->name, size, p);
1181
1182 case EVIOCGPHYS(0):
1183 return str_to_user(dev->phys, size, p);
1184
1185 case EVIOCGUNIQ(0):
1186 return str_to_user(dev->uniq, size, p);
1187
1188 case EVIOC_MASK_SIZE(EVIOCSFF):
1189 if (input_ff_effect_from_user(p, size, &effect))
1190 return -EFAULT;
1191
1192 error = input_ff_upload(dev, &effect, file);
1193 if (error)
1194 return error;
1195
1196 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
1197 return -EFAULT;
1198
1199 return 0;
1200 }
1201
1202 /* Multi-number variable-length handlers */
1203 if (_IOC_TYPE(cmd) != 'E')
1204 return -EINVAL;
1205
1206 if (_IOC_DIR(cmd) == _IOC_READ) {
1207
1208 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
1209 return handle_eviocgbit(dev,
1210 _IOC_NR(cmd) & EV_MAX, size,
1211 p, compat_mode);
1212
1213 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1214
1215 if (!dev->absinfo)
1216 return -EINVAL;
1217
1218 t = _IOC_NR(cmd) & ABS_MAX;
1219 abs = dev->absinfo[t];
1220
1221 if (copy_to_user(p, &abs, min_t(size_t,
1222 size, sizeof(struct input_absinfo))))
1223 return -EFAULT;
1224
1225 return 0;
1226 }
1227 }
1228
1229 if (_IOC_DIR(cmd) == _IOC_WRITE) {
1230
1231 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1232
1233 if (!dev->absinfo)
1234 return -EINVAL;
1235
1236 t = _IOC_NR(cmd) & ABS_MAX;
1237
1238 if (copy_from_user(&abs, p, min_t(size_t,
1239 size, sizeof(struct input_absinfo))))
1240 return -EFAULT;
1241
1242 if (size < sizeof(struct input_absinfo))
1243 abs.resolution = 0;
1244
1245 /* We can't change number of reserved MT slots */
1246 if (t == ABS_MT_SLOT)
1247 return -EINVAL;
1248
1249 /*
1250 * Take event lock to ensure that we are not
1251 * changing device parameters in the middle
1252 * of event.
1253 */
1254 spin_lock_irq(&dev->event_lock);
1255 dev->absinfo[t] = abs;
1256 spin_unlock_irq(&dev->event_lock);
1257
1258 return 0;
1259 }
1260 }
1261
1262 return -EINVAL;
1263}
1264
1265static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1266 void __user *p, int compat_mode)
1267{
1268 struct evdev_client *client = file->private_data;
1269 struct evdev *evdev = client->evdev;
1270 int retval;
1271
1272 retval = mutex_lock_interruptible(&evdev->mutex);
1273 if (retval)
1274 return retval;
1275
1276 if (!evdev->exist || client->revoked) {
1277 retval = -ENODEV;
1278 goto out;
1279 }
1280
1281 retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1282
1283 out:
1284 mutex_unlock(&evdev->mutex);
1285 return retval;
1286}
1287
1288static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1289{
1290 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1291}
1292
1293#ifdef CONFIG_COMPAT
1294static long evdev_ioctl_compat(struct file *file,
1295 unsigned int cmd, unsigned long arg)
1296{
1297 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1298}
1299#endif
1300
1301static const struct file_operations evdev_fops = {
1302 .owner = THIS_MODULE,
1303 .read = evdev_read,
1304 .write = evdev_write,
1305 .poll = evdev_poll,
1306 .open = evdev_open,
1307 .release = evdev_release,
1308 .unlocked_ioctl = evdev_ioctl,
1309#ifdef CONFIG_COMPAT
1310 .compat_ioctl = evdev_ioctl_compat,
1311#endif
1312 .fasync = evdev_fasync,
1313 .flush = evdev_flush,
1314 .llseek = no_llseek,
1315};
1316
1317/*
1318 * Mark device non-existent. This disables writes, ioctls and
1319 * prevents new users from opening the device. Already posted
1320 * blocking reads will stay, however new ones will fail.
1321 */
1322static void evdev_mark_dead(struct evdev *evdev)
1323{
1324 mutex_lock(&evdev->mutex);
1325 evdev->exist = false;
1326 mutex_unlock(&evdev->mutex);
1327}
1328
1329static void evdev_cleanup(struct evdev *evdev)
1330{
1331 struct input_handle *handle = &evdev->handle;
1332
1333 evdev_mark_dead(evdev);
1334 evdev_hangup(evdev);
1335
1336 /* evdev is marked dead so no one else accesses evdev->open */
1337 if (evdev->open) {
1338 input_flush_device(handle, NULL);
1339 input_close_device(handle);
1340 }
1341}
1342
1343/*
1344 * Create new evdev device. Note that input core serializes calls
1345 * to connect and disconnect.
1346 */
1347static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1348 const struct input_device_id *id)
1349{
1350 struct evdev *evdev;
1351 int minor;
1352 int dev_no;
1353 int error;
1354
1355 minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1356 if (minor < 0) {
1357 error = minor;
1358 pr_err("failed to reserve new minor: %d\n", error);
1359 return error;
1360 }
1361
1362 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1363 if (!evdev) {
1364 error = -ENOMEM;
1365 goto err_free_minor;
1366 }
1367
1368 INIT_LIST_HEAD(&evdev->client_list);
1369 spin_lock_init(&evdev->client_lock);
1370 mutex_init(&evdev->mutex);
1371 init_waitqueue_head(&evdev->wait);
1372 evdev->exist = true;
1373
1374 dev_no = minor;
1375 /* Normalize device number if it falls into legacy range */
1376 if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1377 dev_no -= EVDEV_MINOR_BASE;
1378 dev_set_name(&evdev->dev, "event%d", dev_no);
1379
1380 evdev->handle.dev = input_get_device(dev);
1381 evdev->handle.name = dev_name(&evdev->dev);
1382 evdev->handle.handler = handler;
1383 evdev->handle.private = evdev;
1384
1385 evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1386 evdev->dev.class = &input_class;
1387 evdev->dev.parent = &dev->dev;
1388 evdev->dev.release = evdev_free;
1389 device_initialize(&evdev->dev);
1390
1391 error = input_register_handle(&evdev->handle);
1392 if (error)
1393 goto err_free_evdev;
1394
1395 cdev_init(&evdev->cdev, &evdev_fops);
1396
1397 error = cdev_device_add(&evdev->cdev, &evdev->dev);
1398 if (error)
1399 goto err_cleanup_evdev;
1400
1401 return 0;
1402
1403 err_cleanup_evdev:
1404 evdev_cleanup(evdev);
1405 input_unregister_handle(&evdev->handle);
1406 err_free_evdev:
1407 put_device(&evdev->dev);
1408 err_free_minor:
1409 input_free_minor(minor);
1410 return error;
1411}
1412
1413static void evdev_disconnect(struct input_handle *handle)
1414{
1415 struct evdev *evdev = handle->private;
1416
1417 cdev_device_del(&evdev->cdev, &evdev->dev);
1418 evdev_cleanup(evdev);
1419 input_free_minor(MINOR(evdev->dev.devt));
1420 input_unregister_handle(handle);
1421 put_device(&evdev->dev);
1422}
1423
1424static const struct input_device_id evdev_ids[] = {
1425 { .driver_info = 1 }, /* Matches all devices */
1426 { }, /* Terminating zero entry */
1427};
1428
1429MODULE_DEVICE_TABLE(input, evdev_ids);
1430
1431static struct input_handler evdev_handler = {
1432 .event = evdev_event,
1433 .events = evdev_events,
1434 .connect = evdev_connect,
1435 .disconnect = evdev_disconnect,
1436 .legacy_minors = true,
1437 .minor = EVDEV_MINOR_BASE,
1438 .name = "evdev",
1439 .id_table = evdev_ids,
1440};
1441
1442static int __init evdev_init(void)
1443{
1444 return input_register_handler(&evdev_handler);
1445}
1446
1447static void __exit evdev_exit(void)
1448{
1449 input_unregister_handler(&evdev_handler);
1450}
1451
1452module_init(evdev_init);
1453module_exit(evdev_exit);
1454
1455MODULE_AUTHOR("Vojtech Pavlik <[email protected]>");
1456MODULE_DESCRIPTION("Input driver event char devices");
1457MODULE_LICENSE("GPL");