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 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
40struct 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[] __counted_by(bufsize);
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(dev: 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(lock: &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(lock: &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 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(lock: &client->buffer_lock);
262
263 for (v = vals; v != vals + count; v++) {
264 if (__evdev_is_filtered(client, type: v->type, code: 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: &event);
279 }
280
281 spin_unlock(lock: &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 */
291static unsigned int evdev_events(struct input_handle *handle,
292 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(dev: 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 return count;
311}
312
313static int evdev_fasync(int fd, struct file *file, int on)
314{
315 struct evdev_client *client = file->private_data;
316
317 return fasync_helper(fd, file, on, &client->fasync);
318}
319
320static void evdev_free(struct device *dev)
321{
322 struct evdev *evdev = container_of(dev, struct evdev, dev);
323
324 input_put_device(dev: evdev->handle.dev);
325 kfree(objp: evdev);
326}
327
328/*
329 * Grabs an event device (along with underlying input device).
330 * This function is called with evdev->mutex taken.
331 */
332static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
333{
334 int error;
335
336 if (evdev->grab)
337 return -EBUSY;
338
339 error = input_grab_device(&evdev->handle);
340 if (error)
341 return error;
342
343 rcu_assign_pointer(evdev->grab, client);
344
345 return 0;
346}
347
348static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
349{
350 struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
351 lockdep_is_held(&evdev->mutex));
352
353 if (grab != client)
354 return -EINVAL;
355
356 rcu_assign_pointer(evdev->grab, NULL);
357 synchronize_rcu();
358 input_release_device(&evdev->handle);
359
360 return 0;
361}
362
363static void evdev_attach_client(struct evdev *evdev,
364 struct evdev_client *client)
365{
366 spin_lock(lock: &evdev->client_lock);
367 list_add_tail_rcu(new: &client->node, head: &evdev->client_list);
368 spin_unlock(lock: &evdev->client_lock);
369}
370
371static void evdev_detach_client(struct evdev *evdev,
372 struct evdev_client *client)
373{
374 spin_lock(lock: &evdev->client_lock);
375 list_del_rcu(entry: &client->node);
376 spin_unlock(lock: &evdev->client_lock);
377 synchronize_rcu();
378}
379
380static int evdev_open_device(struct evdev *evdev)
381{
382 int retval;
383
384 retval = mutex_lock_interruptible(lock: &evdev->mutex);
385 if (retval)
386 return retval;
387
388 if (!evdev->exist)
389 retval = -ENODEV;
390 else if (!evdev->open++) {
391 retval = input_open_device(&evdev->handle);
392 if (retval)
393 evdev->open--;
394 }
395
396 mutex_unlock(lock: &evdev->mutex);
397 return retval;
398}
399
400static void evdev_close_device(struct evdev *evdev)
401{
402 mutex_lock(lock: &evdev->mutex);
403
404 if (evdev->exist && !--evdev->open)
405 input_close_device(&evdev->handle);
406
407 mutex_unlock(lock: &evdev->mutex);
408}
409
410/*
411 * Wake up users waiting for IO so they can disconnect from
412 * dead device.
413 */
414static void evdev_hangup(struct evdev *evdev)
415{
416 struct evdev_client *client;
417
418 spin_lock(lock: &evdev->client_lock);
419 list_for_each_entry(client, &evdev->client_list, node) {
420 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
421 wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR);
422 }
423 spin_unlock(lock: &evdev->client_lock);
424}
425
426static int evdev_release(struct inode *inode, struct file *file)
427{
428 struct evdev_client *client = file->private_data;
429 struct evdev *evdev = client->evdev;
430 unsigned int i;
431
432 mutex_lock(lock: &evdev->mutex);
433
434 if (evdev->exist && !client->revoked)
435 input_flush_device(handle: &evdev->handle, file);
436
437 evdev_ungrab(evdev, client);
438 mutex_unlock(lock: &evdev->mutex);
439
440 evdev_detach_client(evdev, client);
441
442 for (i = 0; i < EV_CNT; ++i)
443 bitmap_free(bitmap: client->evmasks[i]);
444
445 kvfree(addr: client);
446
447 evdev_close_device(evdev);
448
449 return 0;
450}
451
452static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
453{
454 unsigned int n_events =
455 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
456 EVDEV_MIN_BUFFER_SIZE);
457
458 return roundup_pow_of_two(n_events);
459}
460
461static int evdev_open(struct inode *inode, struct file *file)
462{
463 struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
464 unsigned int bufsize = evdev_compute_buffer_size(dev: evdev->handle.dev);
465 struct evdev_client *client;
466 int error;
467
468 client = kvzalloc(struct_size(client, buffer, bufsize), GFP_KERNEL);
469 if (!client)
470 return -ENOMEM;
471
472 init_waitqueue_head(&client->wait);
473 client->bufsize = bufsize;
474 spin_lock_init(&client->buffer_lock);
475 client->evdev = evdev;
476 evdev_attach_client(evdev, client);
477
478 error = evdev_open_device(evdev);
479 if (error)
480 goto err_free_client;
481
482 file->private_data = client;
483 stream_open(inode, filp: file);
484
485 return 0;
486
487 err_free_client:
488 evdev_detach_client(evdev, client);
489 kvfree(addr: client);
490 return error;
491}
492
493static ssize_t evdev_write(struct file *file, const char __user *buffer,
494 size_t count, loff_t *ppos)
495{
496 struct evdev_client *client = file->private_data;
497 struct evdev *evdev = client->evdev;
498 struct input_event event;
499 int retval = 0;
500
501 /*
502 * Limit amount of data we inject into the input subsystem so that
503 * we do not hold evdev->mutex for too long. 4096 bytes corresponds
504 * to 170 input events.
505 */
506 count = min(count, 4096);
507
508 if (count != 0 && count < input_event_size())
509 return -EINVAL;
510
511 retval = mutex_lock_interruptible(lock: &evdev->mutex);
512 if (retval)
513 return retval;
514
515 if (!evdev->exist || client->revoked) {
516 retval = -ENODEV;
517 goto out;
518 }
519
520 while (retval + input_event_size() <= count) {
521
522 if (input_event_from_user(buffer: buffer + retval, event: &event)) {
523 retval = -EFAULT;
524 goto out;
525 }
526 retval += input_event_size();
527
528 input_inject_event(handle: &evdev->handle,
529 type: event.type, code: event.code, value: event.value);
530 cond_resched();
531 }
532
533 out:
534 mutex_unlock(lock: &evdev->mutex);
535 return retval;
536}
537
538static int evdev_fetch_next_event(struct evdev_client *client,
539 struct input_event *event)
540{
541 int have_event;
542
543 spin_lock_irq(lock: &client->buffer_lock);
544
545 have_event = client->packet_head != client->tail;
546 if (have_event) {
547 *event = client->buffer[client->tail++];
548 client->tail &= client->bufsize - 1;
549 }
550
551 spin_unlock_irq(lock: &client->buffer_lock);
552
553 return have_event;
554}
555
556static ssize_t evdev_read(struct file *file, char __user *buffer,
557 size_t count, loff_t *ppos)
558{
559 struct evdev_client *client = file->private_data;
560 struct evdev *evdev = client->evdev;
561 struct input_event event;
562 size_t read = 0;
563 int error;
564
565 if (count != 0 && count < input_event_size())
566 return -EINVAL;
567
568 for (;;) {
569 if (!evdev->exist || client->revoked)
570 return -ENODEV;
571
572 if (client->packet_head == client->tail &&
573 (file->f_flags & O_NONBLOCK))
574 return -EAGAIN;
575
576 /*
577 * count == 0 is special - no IO is done but we check
578 * for error conditions (see above).
579 */
580 if (count == 0)
581 break;
582
583 while (read + input_event_size() <= count &&
584 evdev_fetch_next_event(client, event: &event)) {
585
586 if (input_event_to_user(buffer: buffer + read, event: &event))
587 return -EFAULT;
588
589 read += input_event_size();
590 }
591
592 if (read)
593 break;
594
595 if (!(file->f_flags & O_NONBLOCK)) {
596 error = wait_event_interruptible(client->wait,
597 client->packet_head != client->tail ||
598 !evdev->exist || client->revoked);
599 if (error)
600 return error;
601 }
602 }
603
604 return read;
605}
606
607/* No kernel lock - fine */
608static __poll_t evdev_poll(struct file *file, poll_table *wait)
609{
610 struct evdev_client *client = file->private_data;
611 struct evdev *evdev = client->evdev;
612 __poll_t mask;
613
614 poll_wait(filp: file, wait_address: &client->wait, p: wait);
615
616 if (evdev->exist && !client->revoked)
617 mask = EPOLLOUT | EPOLLWRNORM;
618 else
619 mask = EPOLLHUP | EPOLLERR;
620
621 if (client->packet_head != client->tail)
622 mask |= EPOLLIN | EPOLLRDNORM;
623
624 return mask;
625}
626
627#ifdef CONFIG_COMPAT
628
629#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
630#define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
631
632#ifdef __BIG_ENDIAN
633static int bits_to_user(unsigned long *bits, unsigned int maxbit,
634 unsigned int maxlen, void __user *p, int compat)
635{
636 int len, i;
637
638 if (compat) {
639 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
640 if (len > maxlen)
641 len = maxlen;
642
643 for (i = 0; i < len / sizeof(compat_long_t); i++)
644 if (copy_to_user((compat_long_t __user *) p + i,
645 (compat_long_t *) bits +
646 i + 1 - ((i % 2) << 1),
647 sizeof(compat_long_t)))
648 return -EFAULT;
649 } else {
650 len = BITS_TO_LONGS(maxbit) * sizeof(long);
651 if (len > maxlen)
652 len = maxlen;
653
654 if (copy_to_user(p, bits, len))
655 return -EFAULT;
656 }
657
658 return len;
659}
660
661static int bits_from_user(unsigned long *bits, unsigned int maxbit,
662 unsigned int maxlen, const void __user *p, int compat)
663{
664 int len, i;
665
666 if (compat) {
667 if (maxlen % sizeof(compat_long_t))
668 return -EINVAL;
669
670 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
671 if (len > maxlen)
672 len = maxlen;
673
674 for (i = 0; i < len / sizeof(compat_long_t); i++)
675 if (copy_from_user((compat_long_t *) bits +
676 i + 1 - ((i % 2) << 1),
677 (compat_long_t __user *) p + i,
678 sizeof(compat_long_t)))
679 return -EFAULT;
680 if (i % 2)
681 *((compat_long_t *) bits + i - 1) = 0;
682
683 } else {
684 if (maxlen % sizeof(long))
685 return -EINVAL;
686
687 len = BITS_TO_LONGS(maxbit) * sizeof(long);
688 if (len > maxlen)
689 len = maxlen;
690
691 if (copy_from_user(bits, p, len))
692 return -EFAULT;
693 }
694
695 return len;
696}
697
698#else
699
700static int bits_to_user(unsigned long *bits, unsigned int maxbit,
701 unsigned int maxlen, void __user *p, int compat)
702{
703 int len = compat ?
704 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
705 BITS_TO_LONGS(maxbit) * sizeof(long);
706
707 if (len > maxlen)
708 len = maxlen;
709
710 return copy_to_user(to: p, from: bits, n: len) ? -EFAULT : len;
711}
712
713static int bits_from_user(unsigned long *bits, unsigned int maxbit,
714 unsigned int maxlen, const void __user *p, int compat)
715{
716 size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long);
717 int len;
718
719 if (maxlen % chunk_size)
720 return -EINVAL;
721
722 len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);
723 len *= chunk_size;
724 if (len > maxlen)
725 len = maxlen;
726
727 return copy_from_user(to: bits, from: p, n: len) ? -EFAULT : len;
728}
729
730#endif /* __BIG_ENDIAN */
731
732#else
733
734static int bits_to_user(unsigned long *bits, unsigned int maxbit,
735 unsigned int maxlen, void __user *p, int compat)
736{
737 int len = BITS_TO_LONGS(maxbit) * sizeof(long);
738
739 if (len > maxlen)
740 len = maxlen;
741
742 return copy_to_user(p, bits, len) ? -EFAULT : len;
743}
744
745static int bits_from_user(unsigned long *bits, unsigned int maxbit,
746 unsigned int maxlen, const void __user *p, int compat)
747{
748 int len;
749
750 if (maxlen % sizeof(long))
751 return -EINVAL;
752
753 len = BITS_TO_LONGS(maxbit) * sizeof(long);
754 if (len > maxlen)
755 len = maxlen;
756
757 return copy_from_user(bits, p, len) ? -EFAULT : len;
758}
759
760#endif /* CONFIG_COMPAT */
761
762static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
763{
764 int len;
765
766 if (!str)
767 return -ENOENT;
768
769 len = strlen(str) + 1;
770 if (len > maxlen)
771 len = maxlen;
772
773 return copy_to_user(to: p, from: str, n: len) ? -EFAULT : len;
774}
775
776static int handle_eviocgbit(struct input_dev *dev,
777 unsigned int type, unsigned int size,
778 void __user *p, int compat_mode)
779{
780 unsigned long *bits;
781 int len;
782
783 switch (type) {
784
785 case 0: bits = dev->evbit; len = EV_MAX; break;
786 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
787 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
788 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
789 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
790 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
791 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
792 case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
793 case EV_SW: bits = dev->swbit; len = SW_MAX; break;
794 default: return -EINVAL;
795 }
796
797 return bits_to_user(bits, maxbit: len, maxlen: size, p, compat: compat_mode);
798}
799
800static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
801{
802 struct input_keymap_entry ke = {
803 .len = sizeof(unsigned int),
804 .flags = 0,
805 };
806 int __user *ip = (int __user *)p;
807 int error;
808
809 /* legacy case */
810 if (copy_from_user(to: ke.scancode, from: p, n: sizeof(unsigned int)))
811 return -EFAULT;
812
813 error = input_get_keycode(dev, ke: &ke);
814 if (error)
815 return error;
816
817 if (put_user(ke.keycode, ip + 1))
818 return -EFAULT;
819
820 return 0;
821}
822
823static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
824{
825 struct input_keymap_entry ke;
826 int error;
827
828 if (copy_from_user(to: &ke, from: p, n: sizeof(ke)))
829 return -EFAULT;
830
831 error = input_get_keycode(dev, ke: &ke);
832 if (error)
833 return error;
834
835 if (copy_to_user(to: p, from: &ke, n: sizeof(ke)))
836 return -EFAULT;
837
838 return 0;
839}
840
841static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
842{
843 struct input_keymap_entry ke = {
844 .len = sizeof(unsigned int),
845 .flags = 0,
846 };
847 int __user *ip = (int __user *)p;
848
849 if (copy_from_user(to: ke.scancode, from: p, n: sizeof(unsigned int)))
850 return -EFAULT;
851
852 if (get_user(ke.keycode, ip + 1))
853 return -EFAULT;
854
855 return input_set_keycode(dev, ke: &ke);
856}
857
858static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
859{
860 struct input_keymap_entry ke;
861
862 if (copy_from_user(to: &ke, from: p, n: sizeof(ke)))
863 return -EFAULT;
864
865 if (ke.len > sizeof(ke.scancode))
866 return -EINVAL;
867
868 return input_set_keycode(dev, ke: &ke);
869}
870
871/*
872 * If we transfer state to the user, we should flush all pending events
873 * of the same type from the client's queue. Otherwise, they might end up
874 * with duplicate events, which can screw up client's state tracking.
875 * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
876 * event so user-space will notice missing events.
877 *
878 * LOCKING:
879 * We need to take event_lock before buffer_lock to avoid dead-locks. But we
880 * need the even_lock only to guarantee consistent state. We can safely release
881 * it while flushing the queue. This allows input-core to handle filters while
882 * we flush the queue.
883 */
884static int evdev_handle_get_val(struct evdev_client *client,
885 struct input_dev *dev, unsigned int type,
886 unsigned long *bits, unsigned int maxbit,
887 unsigned int maxlen, void __user *p,
888 int compat)
889{
890 int ret;
891 unsigned long *mem;
892
893 mem = bitmap_alloc(nbits: maxbit, GFP_KERNEL);
894 if (!mem)
895 return -ENOMEM;
896
897 spin_lock_irq(lock: &dev->event_lock);
898 spin_lock(lock: &client->buffer_lock);
899
900 bitmap_copy(dst: mem, src: bits, nbits: maxbit);
901
902 spin_unlock(lock: &dev->event_lock);
903
904 __evdev_flush_queue(client, type);
905
906 spin_unlock_irq(lock: &client->buffer_lock);
907
908 ret = bits_to_user(bits: mem, maxbit, maxlen, p, compat);
909 if (ret < 0)
910 evdev_queue_syn_dropped(client);
911
912 bitmap_free(bitmap: mem);
913
914 return ret;
915}
916
917static int evdev_handle_mt_request(struct input_dev *dev,
918 unsigned int size,
919 int __user *ip)
920{
921 const struct input_mt *mt = dev->mt;
922 unsigned int code;
923 int max_slots;
924 int i;
925
926 if (get_user(code, &ip[0]))
927 return -EFAULT;
928 if (!mt || !input_is_mt_value(axis: code))
929 return -EINVAL;
930
931 max_slots = (size - sizeof(__u32)) / sizeof(__s32);
932 for (i = 0; i < mt->num_slots && i < max_slots; i++) {
933 int value = input_mt_get_value(slot: &mt->slots[i], code);
934 if (put_user(value, &ip[1 + i]))
935 return -EFAULT;
936 }
937
938 return 0;
939}
940
941static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
942 struct file *file)
943{
944 client->revoked = true;
945 evdev_ungrab(evdev, client);
946 input_flush_device(handle: &evdev->handle, file);
947 wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR);
948
949 return 0;
950}
951
952/* must be called with evdev-mutex held */
953static int evdev_set_mask(struct evdev_client *client,
954 unsigned int type,
955 const void __user *codes,
956 u32 codes_size,
957 int compat)
958{
959 unsigned long flags, *mask, *oldmask;
960 size_t cnt;
961 int error;
962
963 /* we allow unknown types and 'codes_size > size' for forward-compat */
964 cnt = evdev_get_mask_cnt(type);
965 if (!cnt)
966 return 0;
967
968 mask = bitmap_zalloc(nbits: cnt, GFP_KERNEL);
969 if (!mask)
970 return -ENOMEM;
971
972 error = bits_from_user(bits: mask, maxbit: cnt - 1, maxlen: codes_size, p: codes, compat);
973 if (error < 0) {
974 bitmap_free(bitmap: mask);
975 return error;
976 }
977
978 spin_lock_irqsave(&client->buffer_lock, flags);
979 oldmask = client->evmasks[type];
980 client->evmasks[type] = mask;
981 spin_unlock_irqrestore(lock: &client->buffer_lock, flags);
982
983 bitmap_free(bitmap: oldmask);
984
985 return 0;
986}
987
988/* must be called with evdev-mutex held */
989static int evdev_get_mask(struct evdev_client *client,
990 unsigned int type,
991 void __user *codes,
992 u32 codes_size,
993 int compat)
994{
995 unsigned long *mask;
996 size_t cnt, size, xfer_size;
997 int i;
998 int error;
999
1000 /* we allow unknown types and 'codes_size > size' for forward-compat */
1001 cnt = evdev_get_mask_cnt(type);
1002 size = sizeof(unsigned long) * BITS_TO_LONGS(cnt);
1003 xfer_size = min_t(size_t, codes_size, size);
1004
1005 if (cnt > 0) {
1006 mask = client->evmasks[type];
1007 if (mask) {
1008 error = bits_to_user(bits: mask, maxbit: cnt - 1,
1009 maxlen: xfer_size, p: codes, compat);
1010 if (error < 0)
1011 return error;
1012 } else {
1013 /* fake mask with all bits set */
1014 for (i = 0; i < xfer_size; i++)
1015 if (put_user(0xffU, (u8 __user *)codes + i))
1016 return -EFAULT;
1017 }
1018 }
1019
1020 if (xfer_size < codes_size)
1021 if (clear_user(to: codes + xfer_size, n: codes_size - xfer_size))
1022 return -EFAULT;
1023
1024 return 0;
1025}
1026
1027static long evdev_do_ioctl(struct file *file, unsigned int cmd,
1028 void __user *p, int compat_mode)
1029{
1030 struct evdev_client *client = file->private_data;
1031 struct evdev *evdev = client->evdev;
1032 struct input_dev *dev = evdev->handle.dev;
1033 struct input_absinfo abs;
1034 struct input_mask mask;
1035 struct ff_effect effect;
1036 int __user *ip = (int __user *)p;
1037 unsigned int i, t, u, v;
1038 unsigned int size;
1039 int error;
1040
1041 /* First we check for fixed-length commands */
1042 switch (cmd) {
1043
1044 case EVIOCGVERSION:
1045 return put_user(EV_VERSION, ip);
1046
1047 case EVIOCGID:
1048 if (copy_to_user(to: p, from: &dev->id, n: sizeof(struct input_id)))
1049 return -EFAULT;
1050 return 0;
1051
1052 case EVIOCGREP:
1053 if (!test_bit(EV_REP, dev->evbit))
1054 return -ENOSYS;
1055 if (put_user(dev->rep[REP_DELAY], ip))
1056 return -EFAULT;
1057 if (put_user(dev->rep[REP_PERIOD], ip + 1))
1058 return -EFAULT;
1059 return 0;
1060
1061 case EVIOCSREP:
1062 if (!test_bit(EV_REP, dev->evbit))
1063 return -ENOSYS;
1064 if (get_user(u, ip))
1065 return -EFAULT;
1066 if (get_user(v, ip + 1))
1067 return -EFAULT;
1068
1069 input_inject_event(handle: &evdev->handle, EV_REP, REP_DELAY, value: u);
1070 input_inject_event(handle: &evdev->handle, EV_REP, REP_PERIOD, value: v);
1071
1072 return 0;
1073
1074 case EVIOCRMFF:
1075 return input_ff_erase(dev, effect_id: (int)(unsigned long) p, file);
1076
1077 case EVIOCGEFFECTS:
1078 i = test_bit(EV_FF, dev->evbit) ?
1079 dev->ff->max_effects : 0;
1080 if (put_user(i, ip))
1081 return -EFAULT;
1082 return 0;
1083
1084 case EVIOCGRAB:
1085 if (p)
1086 return evdev_grab(evdev, client);
1087 else
1088 return evdev_ungrab(evdev, client);
1089
1090 case EVIOCREVOKE:
1091 if (p)
1092 return -EINVAL;
1093 else
1094 return evdev_revoke(evdev, client, file);
1095
1096 case EVIOCGMASK: {
1097 void __user *codes_ptr;
1098
1099 if (copy_from_user(to: &mask, from: p, n: sizeof(mask)))
1100 return -EFAULT;
1101
1102 codes_ptr = (void __user *)(unsigned long)mask.codes_ptr;
1103 return evdev_get_mask(client,
1104 type: mask.type, codes: codes_ptr, codes_size: mask.codes_size,
1105 compat: compat_mode);
1106 }
1107
1108 case EVIOCSMASK: {
1109 const void __user *codes_ptr;
1110
1111 if (copy_from_user(to: &mask, from: p, n: sizeof(mask)))
1112 return -EFAULT;
1113
1114 codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr;
1115 return evdev_set_mask(client,
1116 type: mask.type, codes: codes_ptr, codes_size: mask.codes_size,
1117 compat: compat_mode);
1118 }
1119
1120 case EVIOCSCLOCKID:
1121 if (copy_from_user(to: &i, from: p, n: sizeof(unsigned int)))
1122 return -EFAULT;
1123
1124 return evdev_set_clk_type(client, clkid: i);
1125
1126 case EVIOCGKEYCODE:
1127 return evdev_handle_get_keycode(dev, p);
1128
1129 case EVIOCSKEYCODE:
1130 return evdev_handle_set_keycode(dev, p);
1131
1132 case EVIOCGKEYCODE_V2:
1133 return evdev_handle_get_keycode_v2(dev, p);
1134
1135 case EVIOCSKEYCODE_V2:
1136 return evdev_handle_set_keycode_v2(dev, p);
1137 }
1138
1139 size = _IOC_SIZE(cmd);
1140
1141 /* Now check variable-length commands */
1142#define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
1143 switch (EVIOC_MASK_SIZE(cmd)) {
1144
1145 case EVIOCGPROP(0):
1146 return bits_to_user(bits: dev->propbit, INPUT_PROP_MAX,
1147 maxlen: size, p, compat: compat_mode);
1148
1149 case EVIOCGMTSLOTS(0):
1150 return evdev_handle_mt_request(dev, size, ip);
1151
1152 case EVIOCGKEY(0):
1153 return evdev_handle_get_val(client, dev, EV_KEY, bits: dev->key,
1154 KEY_MAX, maxlen: size, p, compat: compat_mode);
1155
1156 case EVIOCGLED(0):
1157 return evdev_handle_get_val(client, dev, EV_LED, bits: dev->led,
1158 LED_MAX, maxlen: size, p, compat: compat_mode);
1159
1160 case EVIOCGSND(0):
1161 return evdev_handle_get_val(client, dev, EV_SND, bits: dev->snd,
1162 SND_MAX, maxlen: size, p, compat: compat_mode);
1163
1164 case EVIOCGSW(0):
1165 return evdev_handle_get_val(client, dev, EV_SW, bits: dev->sw,
1166 SW_MAX, maxlen: size, p, compat: compat_mode);
1167
1168 case EVIOCGNAME(0):
1169 return str_to_user(str: dev->name, maxlen: size, p);
1170
1171 case EVIOCGPHYS(0):
1172 return str_to_user(str: dev->phys, maxlen: size, p);
1173
1174 case EVIOCGUNIQ(0):
1175 return str_to_user(str: dev->uniq, maxlen: size, p);
1176
1177 case EVIOC_MASK_SIZE(EVIOCSFF):
1178 if (input_ff_effect_from_user(buffer: p, size, effect: &effect))
1179 return -EFAULT;
1180
1181 error = input_ff_upload(dev, effect: &effect, file);
1182 if (error)
1183 return error;
1184
1185 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
1186 return -EFAULT;
1187
1188 return 0;
1189 }
1190
1191 /* Multi-number variable-length handlers */
1192 if (_IOC_TYPE(cmd) != 'E')
1193 return -EINVAL;
1194
1195 if (_IOC_DIR(cmd) == _IOC_READ) {
1196
1197 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
1198 return handle_eviocgbit(dev,
1199 _IOC_NR(cmd) & EV_MAX, size,
1200 p, compat_mode);
1201
1202 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1203
1204 if (!dev->absinfo)
1205 return -EINVAL;
1206
1207 t = _IOC_NR(cmd) & ABS_MAX;
1208 abs = dev->absinfo[t];
1209
1210 if (copy_to_user(to: p, from: &abs, min_t(size_t,
1211 size, sizeof(struct input_absinfo))))
1212 return -EFAULT;
1213
1214 return 0;
1215 }
1216 }
1217
1218 if (_IOC_DIR(cmd) == _IOC_WRITE) {
1219
1220 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1221
1222 if (!dev->absinfo)
1223 return -EINVAL;
1224
1225 t = _IOC_NR(cmd) & ABS_MAX;
1226
1227 if (copy_from_user(to: &abs, from: p, min_t(size_t,
1228 size, sizeof(struct input_absinfo))))
1229 return -EFAULT;
1230
1231 if (size < sizeof(struct input_absinfo))
1232 abs.resolution = 0;
1233
1234 /* We can't change number of reserved MT slots */
1235 if (t == ABS_MT_SLOT)
1236 return -EINVAL;
1237
1238 /*
1239 * Take event lock to ensure that we are not
1240 * changing device parameters in the middle
1241 * of event.
1242 */
1243 spin_lock_irq(lock: &dev->event_lock);
1244 dev->absinfo[t] = abs;
1245 spin_unlock_irq(lock: &dev->event_lock);
1246
1247 return 0;
1248 }
1249 }
1250
1251 return -EINVAL;
1252}
1253
1254static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1255 void __user *p, int compat_mode)
1256{
1257 struct evdev_client *client = file->private_data;
1258 struct evdev *evdev = client->evdev;
1259 int retval;
1260
1261 retval = mutex_lock_interruptible(lock: &evdev->mutex);
1262 if (retval)
1263 return retval;
1264
1265 if (!evdev->exist || client->revoked) {
1266 retval = -ENODEV;
1267 goto out;
1268 }
1269
1270 retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1271
1272 out:
1273 mutex_unlock(lock: &evdev->mutex);
1274 return retval;
1275}
1276
1277static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1278{
1279 return evdev_ioctl_handler(file, cmd, p: (void __user *)arg, compat_mode: 0);
1280}
1281
1282#ifdef CONFIG_COMPAT
1283static long evdev_ioctl_compat(struct file *file,
1284 unsigned int cmd, unsigned long arg)
1285{
1286 return evdev_ioctl_handler(file, cmd, p: compat_ptr(uptr: arg), compat_mode: 1);
1287}
1288#endif
1289
1290static const struct file_operations evdev_fops = {
1291 .owner = THIS_MODULE,
1292 .read = evdev_read,
1293 .write = evdev_write,
1294 .poll = evdev_poll,
1295 .open = evdev_open,
1296 .release = evdev_release,
1297 .unlocked_ioctl = evdev_ioctl,
1298#ifdef CONFIG_COMPAT
1299 .compat_ioctl = evdev_ioctl_compat,
1300#endif
1301 .fasync = evdev_fasync,
1302};
1303
1304/*
1305 * Mark device non-existent. This disables writes, ioctls and
1306 * prevents new users from opening the device. Already posted
1307 * blocking reads will stay, however new ones will fail.
1308 */
1309static void evdev_mark_dead(struct evdev *evdev)
1310{
1311 mutex_lock(lock: &evdev->mutex);
1312 evdev->exist = false;
1313 mutex_unlock(lock: &evdev->mutex);
1314}
1315
1316static void evdev_cleanup(struct evdev *evdev)
1317{
1318 struct input_handle *handle = &evdev->handle;
1319
1320 evdev_mark_dead(evdev);
1321 evdev_hangup(evdev);
1322
1323 /* evdev is marked dead so no one else accesses evdev->open */
1324 if (evdev->open) {
1325 input_flush_device(handle, NULL);
1326 input_close_device(handle);
1327 }
1328}
1329
1330/*
1331 * Create new evdev device. Note that input core serializes calls
1332 * to connect and disconnect.
1333 */
1334static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1335 const struct input_device_id *id)
1336{
1337 struct evdev *evdev;
1338 int minor;
1339 int dev_no;
1340 int error;
1341
1342 minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, allow_dynamic: true);
1343 if (minor < 0) {
1344 error = minor;
1345 pr_err("failed to reserve new minor: %d\n", error);
1346 return error;
1347 }
1348
1349 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1350 if (!evdev) {
1351 error = -ENOMEM;
1352 goto err_free_minor;
1353 }
1354
1355 INIT_LIST_HEAD(list: &evdev->client_list);
1356 spin_lock_init(&evdev->client_lock);
1357 mutex_init(&evdev->mutex);
1358 evdev->exist = true;
1359
1360 dev_no = minor;
1361 /* Normalize device number if it falls into legacy range */
1362 if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1363 dev_no -= EVDEV_MINOR_BASE;
1364 dev_set_name(dev: &evdev->dev, name: "event%d", dev_no);
1365
1366 evdev->handle.dev = input_get_device(dev);
1367 evdev->handle.name = dev_name(dev: &evdev->dev);
1368 evdev->handle.handler = handler;
1369 evdev->handle.private = evdev;
1370
1371 evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1372 evdev->dev.class = &input_class;
1373 evdev->dev.parent = &dev->dev;
1374 evdev->dev.release = evdev_free;
1375 device_initialize(dev: &evdev->dev);
1376
1377 error = input_register_handle(&evdev->handle);
1378 if (error)
1379 goto err_free_evdev;
1380
1381 cdev_init(&evdev->cdev, &evdev_fops);
1382
1383 error = cdev_device_add(cdev: &evdev->cdev, dev: &evdev->dev);
1384 if (error)
1385 goto err_cleanup_evdev;
1386
1387 return 0;
1388
1389 err_cleanup_evdev:
1390 evdev_cleanup(evdev);
1391 input_unregister_handle(&evdev->handle);
1392 err_free_evdev:
1393 put_device(dev: &evdev->dev);
1394 err_free_minor:
1395 input_free_minor(minor);
1396 return error;
1397}
1398
1399static void evdev_disconnect(struct input_handle *handle)
1400{
1401 struct evdev *evdev = handle->private;
1402
1403 cdev_device_del(cdev: &evdev->cdev, dev: &evdev->dev);
1404 evdev_cleanup(evdev);
1405 input_free_minor(MINOR(evdev->dev.devt));
1406 input_unregister_handle(handle);
1407 put_device(dev: &evdev->dev);
1408}
1409
1410static const struct input_device_id evdev_ids[] = {
1411 {
1412 /* Matches all devices */
1413 .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
1414 .evbit = { BIT_MASK(EV_SYN) },
1415 },
1416 { } /* Terminating zero entry */
1417};
1418
1419MODULE_DEVICE_TABLE(input, evdev_ids);
1420
1421static struct input_handler evdev_handler = {
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
1431static int __init evdev_init(void)
1432{
1433 return input_register_handler(&evdev_handler);
1434}
1435
1436static void __exit evdev_exit(void)
1437{
1438 input_unregister_handler(&evdev_handler);
1439}
1440
1441module_init(evdev_init);
1442module_exit(evdev_exit);
1443
1444MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1445MODULE_DESCRIPTION("Input driver event char devices");
1446MODULE_LICENSE("GPL");
1447