Merge tag 'v5.3-rc4' into next
[sfrench/cifs-2.6.git] / drivers / input / evdev.c
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         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
41 struct 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
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 */
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 */
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
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
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
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
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].input_event_sec =
228                                                 event->input_event_sec;
229                 client->buffer[client->tail].input_event_usec =
230                                                 event->input_event_usec;
231                 client->buffer[client->tail].type = EV_SYN;
232                 client->buffer[client->tail].code = SYN_DROPPED;
233                 client->buffer[client->tail].value = 0;
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
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         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  */
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  */
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
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
329 static 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
343 static 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  */
355 static 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
371 static 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
386 static 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
394 static 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
403 static 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
423 static 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  */
437 static 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
449 static 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
471 static 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
480 static 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 = kzalloc(struct_size(client, buffer, bufsize),
488                          GFP_KERNEL | __GFP_NOWARN);
489         if (!client)
490                 client = vzalloc(struct_size(client, buffer, bufsize));
491         if (!client)
492                 return -ENOMEM;
493
494         client->bufsize = bufsize;
495         spin_lock_init(&client->buffer_lock);
496         client->evdev = evdev;
497         evdev_attach_client(evdev, client);
498
499         error = evdev_open_device(evdev);
500         if (error)
501                 goto err_free_client;
502
503         file->private_data = client;
504         stream_open(inode, file);
505
506         return 0;
507
508  err_free_client:
509         evdev_detach_client(evdev, client);
510         kvfree(client);
511         return error;
512 }
513
514 static ssize_t evdev_write(struct file *file, const char __user *buffer,
515                            size_t count, loff_t *ppos)
516 {
517         struct evdev_client *client = file->private_data;
518         struct evdev *evdev = client->evdev;
519         struct input_event event;
520         int retval = 0;
521
522         if (count != 0 && count < input_event_size())
523                 return -EINVAL;
524
525         retval = mutex_lock_interruptible(&evdev->mutex);
526         if (retval)
527                 return retval;
528
529         if (!evdev->exist || client->revoked) {
530                 retval = -ENODEV;
531                 goto out;
532         }
533
534         while (retval + input_event_size() <= count) {
535
536                 if (input_event_from_user(buffer + retval, &event)) {
537                         retval = -EFAULT;
538                         goto out;
539                 }
540                 retval += input_event_size();
541
542                 input_inject_event(&evdev->handle,
543                                    event.type, event.code, event.value);
544                 cond_resched();
545         }
546
547  out:
548         mutex_unlock(&evdev->mutex);
549         return retval;
550 }
551
552 static int evdev_fetch_next_event(struct evdev_client *client,
553                                   struct input_event *event)
554 {
555         int have_event;
556
557         spin_lock_irq(&client->buffer_lock);
558
559         have_event = client->packet_head != client->tail;
560         if (have_event) {
561                 *event = client->buffer[client->tail++];
562                 client->tail &= client->bufsize - 1;
563         }
564
565         spin_unlock_irq(&client->buffer_lock);
566
567         return have_event;
568 }
569
570 static ssize_t evdev_read(struct file *file, char __user *buffer,
571                           size_t count, loff_t *ppos)
572 {
573         struct evdev_client *client = file->private_data;
574         struct evdev *evdev = client->evdev;
575         struct input_event event;
576         size_t read = 0;
577         int error;
578
579         if (count != 0 && count < input_event_size())
580                 return -EINVAL;
581
582         for (;;) {
583                 if (!evdev->exist || client->revoked)
584                         return -ENODEV;
585
586                 if (client->packet_head == client->tail &&
587                     (file->f_flags & O_NONBLOCK))
588                         return -EAGAIN;
589
590                 /*
591                  * count == 0 is special - no IO is done but we check
592                  * for error conditions (see above).
593                  */
594                 if (count == 0)
595                         break;
596
597                 while (read + input_event_size() <= count &&
598                        evdev_fetch_next_event(client, &event)) {
599
600                         if (input_event_to_user(buffer + read, &event))
601                                 return -EFAULT;
602
603                         read += input_event_size();
604                 }
605
606                 if (read)
607                         break;
608
609                 if (!(file->f_flags & O_NONBLOCK)) {
610                         error = wait_event_interruptible(evdev->wait,
611                                         client->packet_head != client->tail ||
612                                         !evdev->exist || client->revoked);
613                         if (error)
614                                 return error;
615                 }
616         }
617
618         return read;
619 }
620
621 /* No kernel lock - fine */
622 static __poll_t evdev_poll(struct file *file, poll_table *wait)
623 {
624         struct evdev_client *client = file->private_data;
625         struct evdev *evdev = client->evdev;
626         __poll_t mask;
627
628         poll_wait(file, &evdev->wait, wait);
629
630         if (evdev->exist && !client->revoked)
631                 mask = EPOLLOUT | EPOLLWRNORM;
632         else
633                 mask = EPOLLHUP | EPOLLERR;
634
635         if (client->packet_head != client->tail)
636                 mask |= EPOLLIN | EPOLLRDNORM;
637
638         return mask;
639 }
640
641 #ifdef CONFIG_COMPAT
642
643 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
644 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
645
646 #ifdef __BIG_ENDIAN
647 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
648                         unsigned int maxlen, void __user *p, int compat)
649 {
650         int len, i;
651
652         if (compat) {
653                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
654                 if (len > maxlen)
655                         len = maxlen;
656
657                 for (i = 0; i < len / sizeof(compat_long_t); i++)
658                         if (copy_to_user((compat_long_t __user *) p + i,
659                                          (compat_long_t *) bits +
660                                                 i + 1 - ((i % 2) << 1),
661                                          sizeof(compat_long_t)))
662                                 return -EFAULT;
663         } else {
664                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
665                 if (len > maxlen)
666                         len = maxlen;
667
668                 if (copy_to_user(p, bits, len))
669                         return -EFAULT;
670         }
671
672         return len;
673 }
674
675 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
676                           unsigned int maxlen, const void __user *p, int compat)
677 {
678         int len, i;
679
680         if (compat) {
681                 if (maxlen % sizeof(compat_long_t))
682                         return -EINVAL;
683
684                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
685                 if (len > maxlen)
686                         len = maxlen;
687
688                 for (i = 0; i < len / sizeof(compat_long_t); i++)
689                         if (copy_from_user((compat_long_t *) bits +
690                                                 i + 1 - ((i % 2) << 1),
691                                            (compat_long_t __user *) p + i,
692                                            sizeof(compat_long_t)))
693                                 return -EFAULT;
694                 if (i % 2)
695                         *((compat_long_t *) bits + i - 1) = 0;
696
697         } else {
698                 if (maxlen % sizeof(long))
699                         return -EINVAL;
700
701                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
702                 if (len > maxlen)
703                         len = maxlen;
704
705                 if (copy_from_user(bits, p, len))
706                         return -EFAULT;
707         }
708
709         return len;
710 }
711
712 #else
713
714 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
715                         unsigned int maxlen, void __user *p, int compat)
716 {
717         int len = compat ?
718                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
719                         BITS_TO_LONGS(maxbit) * sizeof(long);
720
721         if (len > maxlen)
722                 len = maxlen;
723
724         return copy_to_user(p, bits, len) ? -EFAULT : len;
725 }
726
727 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
728                           unsigned int maxlen, const void __user *p, int compat)
729 {
730         size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long);
731         int len;
732
733         if (maxlen % chunk_size)
734                 return -EINVAL;
735
736         len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);
737         len *= chunk_size;
738         if (len > maxlen)
739                 len = maxlen;
740
741         return copy_from_user(bits, p, len) ? -EFAULT : len;
742 }
743
744 #endif /* __BIG_ENDIAN */
745
746 #else
747
748 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
749                         unsigned int maxlen, void __user *p, int compat)
750 {
751         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
752
753         if (len > maxlen)
754                 len = maxlen;
755
756         return copy_to_user(p, bits, len) ? -EFAULT : len;
757 }
758
759 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
760                           unsigned int maxlen, const void __user *p, int compat)
761 {
762         int len;
763
764         if (maxlen % sizeof(long))
765                 return -EINVAL;
766
767         len = BITS_TO_LONGS(maxbit) * sizeof(long);
768         if (len > maxlen)
769                 len = maxlen;
770
771         return copy_from_user(bits, p, len) ? -EFAULT : len;
772 }
773
774 #endif /* CONFIG_COMPAT */
775
776 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
777 {
778         int len;
779
780         if (!str)
781                 return -ENOENT;
782
783         len = strlen(str) + 1;
784         if (len > maxlen)
785                 len = maxlen;
786
787         return copy_to_user(p, str, len) ? -EFAULT : len;
788 }
789
790 static int handle_eviocgbit(struct input_dev *dev,
791                             unsigned int type, unsigned int size,
792                             void __user *p, int compat_mode)
793 {
794         unsigned long *bits;
795         int len;
796
797         switch (type) {
798
799         case      0: bits = dev->evbit;  len = EV_MAX;  break;
800         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
801         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
802         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
803         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
804         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
805         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
806         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
807         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
808         default: return -EINVAL;
809         }
810
811         return bits_to_user(bits, len, size, p, compat_mode);
812 }
813
814 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
815 {
816         struct input_keymap_entry ke = {
817                 .len    = sizeof(unsigned int),
818                 .flags  = 0,
819         };
820         int __user *ip = (int __user *)p;
821         int error;
822
823         /* legacy case */
824         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
825                 return -EFAULT;
826
827         error = input_get_keycode(dev, &ke);
828         if (error)
829                 return error;
830
831         if (put_user(ke.keycode, ip + 1))
832                 return -EFAULT;
833
834         return 0;
835 }
836
837 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
838 {
839         struct input_keymap_entry ke;
840         int error;
841
842         if (copy_from_user(&ke, p, sizeof(ke)))
843                 return -EFAULT;
844
845         error = input_get_keycode(dev, &ke);
846         if (error)
847                 return error;
848
849         if (copy_to_user(p, &ke, sizeof(ke)))
850                 return -EFAULT;
851
852         return 0;
853 }
854
855 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
856 {
857         struct input_keymap_entry ke = {
858                 .len    = sizeof(unsigned int),
859                 .flags  = 0,
860         };
861         int __user *ip = (int __user *)p;
862
863         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
864                 return -EFAULT;
865
866         if (get_user(ke.keycode, ip + 1))
867                 return -EFAULT;
868
869         return input_set_keycode(dev, &ke);
870 }
871
872 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
873 {
874         struct input_keymap_entry ke;
875
876         if (copy_from_user(&ke, p, sizeof(ke)))
877                 return -EFAULT;
878
879         if (ke.len > sizeof(ke.scancode))
880                 return -EINVAL;
881
882         return input_set_keycode(dev, &ke);
883 }
884
885 /*
886  * If we transfer state to the user, we should flush all pending events
887  * of the same type from the client's queue. Otherwise, they might end up
888  * with duplicate events, which can screw up client's state tracking.
889  * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
890  * event so user-space will notice missing events.
891  *
892  * LOCKING:
893  * We need to take event_lock before buffer_lock to avoid dead-locks. But we
894  * need the even_lock only to guarantee consistent state. We can safely release
895  * it while flushing the queue. This allows input-core to handle filters while
896  * we flush the queue.
897  */
898 static int evdev_handle_get_val(struct evdev_client *client,
899                                 struct input_dev *dev, unsigned int type,
900                                 unsigned long *bits, unsigned int maxbit,
901                                 unsigned int maxlen, void __user *p,
902                                 int compat)
903 {
904         int ret;
905         unsigned long *mem;
906
907         mem = bitmap_alloc(maxbit, GFP_KERNEL);
908         if (!mem)
909                 return -ENOMEM;
910
911         spin_lock_irq(&dev->event_lock);
912         spin_lock(&client->buffer_lock);
913
914         bitmap_copy(mem, bits, maxbit);
915
916         spin_unlock(&dev->event_lock);
917
918         __evdev_flush_queue(client, type);
919
920         spin_unlock_irq(&client->buffer_lock);
921
922         ret = bits_to_user(mem, maxbit, maxlen, p, compat);
923         if (ret < 0)
924                 evdev_queue_syn_dropped(client);
925
926         bitmap_free(mem);
927
928         return ret;
929 }
930
931 static int evdev_handle_mt_request(struct input_dev *dev,
932                                    unsigned int size,
933                                    int __user *ip)
934 {
935         const struct input_mt *mt = dev->mt;
936         unsigned int code;
937         int max_slots;
938         int i;
939
940         if (get_user(code, &ip[0]))
941                 return -EFAULT;
942         if (!mt || !input_is_mt_value(code))
943                 return -EINVAL;
944
945         max_slots = (size - sizeof(__u32)) / sizeof(__s32);
946         for (i = 0; i < mt->num_slots && i < max_slots; i++) {
947                 int value = input_mt_get_value(&mt->slots[i], code);
948                 if (put_user(value, &ip[1 + i]))
949                         return -EFAULT;
950         }
951
952         return 0;
953 }
954
955 static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
956                         struct file *file)
957 {
958         client->revoked = true;
959         evdev_ungrab(evdev, client);
960         input_flush_device(&evdev->handle, file);
961         wake_up_interruptible(&evdev->wait);
962
963         return 0;
964 }
965
966 /* must be called with evdev-mutex held */
967 static int evdev_set_mask(struct evdev_client *client,
968                           unsigned int type,
969                           const void __user *codes,
970                           u32 codes_size,
971                           int compat)
972 {
973         unsigned long flags, *mask, *oldmask;
974         size_t cnt;
975         int error;
976
977         /* we allow unknown types and 'codes_size > size' for forward-compat */
978         cnt = evdev_get_mask_cnt(type);
979         if (!cnt)
980                 return 0;
981
982         mask = bitmap_zalloc(cnt, GFP_KERNEL);
983         if (!mask)
984                 return -ENOMEM;
985
986         error = bits_from_user(mask, cnt - 1, codes_size, codes, compat);
987         if (error < 0) {
988                 bitmap_free(mask);
989                 return error;
990         }
991
992         spin_lock_irqsave(&client->buffer_lock, flags);
993         oldmask = client->evmasks[type];
994         client->evmasks[type] = mask;
995         spin_unlock_irqrestore(&client->buffer_lock, flags);
996
997         bitmap_free(oldmask);
998
999         return 0;
1000 }
1001
1002 /* must be called with evdev-mutex held */
1003 static int evdev_get_mask(struct evdev_client *client,
1004                           unsigned int type,
1005                           void __user *codes,
1006                           u32 codes_size,
1007                           int compat)
1008 {
1009         unsigned long *mask;
1010         size_t cnt, size, xfer_size;
1011         int i;
1012         int error;
1013
1014         /* we allow unknown types and 'codes_size > size' for forward-compat */
1015         cnt = evdev_get_mask_cnt(type);
1016         size = sizeof(unsigned long) * BITS_TO_LONGS(cnt);
1017         xfer_size = min_t(size_t, codes_size, size);
1018
1019         if (cnt > 0) {
1020                 mask = client->evmasks[type];
1021                 if (mask) {
1022                         error = bits_to_user(mask, cnt - 1,
1023                                              xfer_size, codes, compat);
1024                         if (error < 0)
1025                                 return error;
1026                 } else {
1027                         /* fake mask with all bits set */
1028                         for (i = 0; i < xfer_size; i++)
1029                                 if (put_user(0xffU, (u8 __user *)codes + i))
1030                                         return -EFAULT;
1031                 }
1032         }
1033
1034         if (xfer_size < codes_size)
1035                 if (clear_user(codes + xfer_size, codes_size - xfer_size))
1036                         return -EFAULT;
1037
1038         return 0;
1039 }
1040
1041 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
1042                            void __user *p, int compat_mode)
1043 {
1044         struct evdev_client *client = file->private_data;
1045         struct evdev *evdev = client->evdev;
1046         struct input_dev *dev = evdev->handle.dev;
1047         struct input_absinfo abs;
1048         struct input_mask mask;
1049         struct ff_effect effect;
1050         int __user *ip = (int __user *)p;
1051         unsigned int i, t, u, v;
1052         unsigned int size;
1053         int error;
1054
1055         /* First we check for fixed-length commands */
1056         switch (cmd) {
1057
1058         case EVIOCGVERSION:
1059                 return put_user(EV_VERSION, ip);
1060
1061         case EVIOCGID:
1062                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
1063                         return -EFAULT;
1064                 return 0;
1065
1066         case EVIOCGREP:
1067                 if (!test_bit(EV_REP, dev->evbit))
1068                         return -ENOSYS;
1069                 if (put_user(dev->rep[REP_DELAY], ip))
1070                         return -EFAULT;
1071                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
1072                         return -EFAULT;
1073                 return 0;
1074
1075         case EVIOCSREP:
1076                 if (!test_bit(EV_REP, dev->evbit))
1077                         return -ENOSYS;
1078                 if (get_user(u, ip))
1079                         return -EFAULT;
1080                 if (get_user(v, ip + 1))
1081                         return -EFAULT;
1082
1083                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
1084                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
1085
1086                 return 0;
1087
1088         case EVIOCRMFF:
1089                 return input_ff_erase(dev, (int)(unsigned long) p, file);
1090
1091         case EVIOCGEFFECTS:
1092                 i = test_bit(EV_FF, dev->evbit) ?
1093                                 dev->ff->max_effects : 0;
1094                 if (put_user(i, ip))
1095                         return -EFAULT;
1096                 return 0;
1097
1098         case EVIOCGRAB:
1099                 if (p)
1100                         return evdev_grab(evdev, client);
1101                 else
1102                         return evdev_ungrab(evdev, client);
1103
1104         case EVIOCREVOKE:
1105                 if (p)
1106                         return -EINVAL;
1107                 else
1108                         return evdev_revoke(evdev, client, file);
1109
1110         case EVIOCGMASK: {
1111                 void __user *codes_ptr;
1112
1113                 if (copy_from_user(&mask, p, sizeof(mask)))
1114                         return -EFAULT;
1115
1116                 codes_ptr = (void __user *)(unsigned long)mask.codes_ptr;
1117                 return evdev_get_mask(client,
1118                                       mask.type, codes_ptr, mask.codes_size,
1119                                       compat_mode);
1120         }
1121
1122         case EVIOCSMASK: {
1123                 const void __user *codes_ptr;
1124
1125                 if (copy_from_user(&mask, p, sizeof(mask)))
1126                         return -EFAULT;
1127
1128                 codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr;
1129                 return evdev_set_mask(client,
1130                                       mask.type, codes_ptr, mask.codes_size,
1131                                       compat_mode);
1132         }
1133
1134         case EVIOCSCLOCKID:
1135                 if (copy_from_user(&i, p, sizeof(unsigned int)))
1136                         return -EFAULT;
1137
1138                 return evdev_set_clk_type(client, i);
1139
1140         case EVIOCGKEYCODE:
1141                 return evdev_handle_get_keycode(dev, p);
1142
1143         case EVIOCSKEYCODE:
1144                 return evdev_handle_set_keycode(dev, p);
1145
1146         case EVIOCGKEYCODE_V2:
1147                 return evdev_handle_get_keycode_v2(dev, p);
1148
1149         case EVIOCSKEYCODE_V2:
1150                 return evdev_handle_set_keycode_v2(dev, p);
1151         }
1152
1153         size = _IOC_SIZE(cmd);
1154
1155         /* Now check variable-length commands */
1156 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
1157         switch (EVIOC_MASK_SIZE(cmd)) {
1158
1159         case EVIOCGPROP(0):
1160                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
1161                                     size, p, compat_mode);
1162
1163         case EVIOCGMTSLOTS(0):
1164                 return evdev_handle_mt_request(dev, size, ip);
1165
1166         case EVIOCGKEY(0):
1167                 return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
1168                                             KEY_MAX, size, p, compat_mode);
1169
1170         case EVIOCGLED(0):
1171                 return evdev_handle_get_val(client, dev, EV_LED, dev->led,
1172                                             LED_MAX, size, p, compat_mode);
1173
1174         case EVIOCGSND(0):
1175                 return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
1176                                             SND_MAX, size, p, compat_mode);
1177
1178         case EVIOCGSW(0):
1179                 return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
1180                                             SW_MAX, size, p, compat_mode);
1181
1182         case EVIOCGNAME(0):
1183                 return str_to_user(dev->name, size, p);
1184
1185         case EVIOCGPHYS(0):
1186                 return str_to_user(dev->phys, size, p);
1187
1188         case EVIOCGUNIQ(0):
1189                 return str_to_user(dev->uniq, size, p);
1190
1191         case EVIOC_MASK_SIZE(EVIOCSFF):
1192                 if (input_ff_effect_from_user(p, size, &effect))
1193                         return -EFAULT;
1194
1195                 error = input_ff_upload(dev, &effect, file);
1196                 if (error)
1197                         return error;
1198
1199                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
1200                         return -EFAULT;
1201
1202                 return 0;
1203         }
1204
1205         /* Multi-number variable-length handlers */
1206         if (_IOC_TYPE(cmd) != 'E')
1207                 return -EINVAL;
1208
1209         if (_IOC_DIR(cmd) == _IOC_READ) {
1210
1211                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
1212                         return handle_eviocgbit(dev,
1213                                                 _IOC_NR(cmd) & EV_MAX, size,
1214                                                 p, compat_mode);
1215
1216                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1217
1218                         if (!dev->absinfo)
1219                                 return -EINVAL;
1220
1221                         t = _IOC_NR(cmd) & ABS_MAX;
1222                         abs = dev->absinfo[t];
1223
1224                         if (copy_to_user(p, &abs, min_t(size_t,
1225                                         size, sizeof(struct input_absinfo))))
1226                                 return -EFAULT;
1227
1228                         return 0;
1229                 }
1230         }
1231
1232         if (_IOC_DIR(cmd) == _IOC_WRITE) {
1233
1234                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1235
1236                         if (!dev->absinfo)
1237                                 return -EINVAL;
1238
1239                         t = _IOC_NR(cmd) & ABS_MAX;
1240
1241                         if (copy_from_user(&abs, p, min_t(size_t,
1242                                         size, sizeof(struct input_absinfo))))
1243                                 return -EFAULT;
1244
1245                         if (size < sizeof(struct input_absinfo))
1246                                 abs.resolution = 0;
1247
1248                         /* We can't change number of reserved MT slots */
1249                         if (t == ABS_MT_SLOT)
1250                                 return -EINVAL;
1251
1252                         /*
1253                          * Take event lock to ensure that we are not
1254                          * changing device parameters in the middle
1255                          * of event.
1256                          */
1257                         spin_lock_irq(&dev->event_lock);
1258                         dev->absinfo[t] = abs;
1259                         spin_unlock_irq(&dev->event_lock);
1260
1261                         return 0;
1262                 }
1263         }
1264
1265         return -EINVAL;
1266 }
1267
1268 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1269                                 void __user *p, int compat_mode)
1270 {
1271         struct evdev_client *client = file->private_data;
1272         struct evdev *evdev = client->evdev;
1273         int retval;
1274
1275         retval = mutex_lock_interruptible(&evdev->mutex);
1276         if (retval)
1277                 return retval;
1278
1279         if (!evdev->exist || client->revoked) {
1280                 retval = -ENODEV;
1281                 goto out;
1282         }
1283
1284         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1285
1286  out:
1287         mutex_unlock(&evdev->mutex);
1288         return retval;
1289 }
1290
1291 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1292 {
1293         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1294 }
1295
1296 #ifdef CONFIG_COMPAT
1297 static long evdev_ioctl_compat(struct file *file,
1298                                 unsigned int cmd, unsigned long arg)
1299 {
1300         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1301 }
1302 #endif
1303
1304 static const struct file_operations evdev_fops = {
1305         .owner          = THIS_MODULE,
1306         .read           = evdev_read,
1307         .write          = evdev_write,
1308         .poll           = evdev_poll,
1309         .open           = evdev_open,
1310         .release        = evdev_release,
1311         .unlocked_ioctl = evdev_ioctl,
1312 #ifdef CONFIG_COMPAT
1313         .compat_ioctl   = evdev_ioctl_compat,
1314 #endif
1315         .fasync         = evdev_fasync,
1316         .flush          = evdev_flush,
1317         .llseek         = no_llseek,
1318 };
1319
1320 /*
1321  * Mark device non-existent. This disables writes, ioctls and
1322  * prevents new users from opening the device. Already posted
1323  * blocking reads will stay, however new ones will fail.
1324  */
1325 static void evdev_mark_dead(struct evdev *evdev)
1326 {
1327         mutex_lock(&evdev->mutex);
1328         evdev->exist = false;
1329         mutex_unlock(&evdev->mutex);
1330 }
1331
1332 static void evdev_cleanup(struct evdev *evdev)
1333 {
1334         struct input_handle *handle = &evdev->handle;
1335
1336         evdev_mark_dead(evdev);
1337         evdev_hangup(evdev);
1338
1339         /* evdev is marked dead so no one else accesses evdev->open */
1340         if (evdev->open) {
1341                 input_flush_device(handle, NULL);
1342                 input_close_device(handle);
1343         }
1344 }
1345
1346 /*
1347  * Create new evdev device. Note that input core serializes calls
1348  * to connect and disconnect.
1349  */
1350 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1351                          const struct input_device_id *id)
1352 {
1353         struct evdev *evdev;
1354         int minor;
1355         int dev_no;
1356         int error;
1357
1358         minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1359         if (minor < 0) {
1360                 error = minor;
1361                 pr_err("failed to reserve new minor: %d\n", error);
1362                 return error;
1363         }
1364
1365         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1366         if (!evdev) {
1367                 error = -ENOMEM;
1368                 goto err_free_minor;
1369         }
1370
1371         INIT_LIST_HEAD(&evdev->client_list);
1372         spin_lock_init(&evdev->client_lock);
1373         mutex_init(&evdev->mutex);
1374         init_waitqueue_head(&evdev->wait);
1375         evdev->exist = true;
1376
1377         dev_no = minor;
1378         /* Normalize device number if it falls into legacy range */
1379         if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1380                 dev_no -= EVDEV_MINOR_BASE;
1381         dev_set_name(&evdev->dev, "event%d", dev_no);
1382
1383         evdev->handle.dev = input_get_device(dev);
1384         evdev->handle.name = dev_name(&evdev->dev);
1385         evdev->handle.handler = handler;
1386         evdev->handle.private = evdev;
1387
1388         evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1389         evdev->dev.class = &input_class;
1390         evdev->dev.parent = &dev->dev;
1391         evdev->dev.release = evdev_free;
1392         device_initialize(&evdev->dev);
1393
1394         error = input_register_handle(&evdev->handle);
1395         if (error)
1396                 goto err_free_evdev;
1397
1398         cdev_init(&evdev->cdev, &evdev_fops);
1399
1400         error = cdev_device_add(&evdev->cdev, &evdev->dev);
1401         if (error)
1402                 goto err_cleanup_evdev;
1403
1404         return 0;
1405
1406  err_cleanup_evdev:
1407         evdev_cleanup(evdev);
1408         input_unregister_handle(&evdev->handle);
1409  err_free_evdev:
1410         put_device(&evdev->dev);
1411  err_free_minor:
1412         input_free_minor(minor);
1413         return error;
1414 }
1415
1416 static void evdev_disconnect(struct input_handle *handle)
1417 {
1418         struct evdev *evdev = handle->private;
1419
1420         cdev_device_del(&evdev->cdev, &evdev->dev);
1421         evdev_cleanup(evdev);
1422         input_free_minor(MINOR(evdev->dev.devt));
1423         input_unregister_handle(handle);
1424         put_device(&evdev->dev);
1425 }
1426
1427 static const struct input_device_id evdev_ids[] = {
1428         { .driver_info = 1 },   /* Matches all devices */
1429         { },                    /* Terminating zero entry */
1430 };
1431
1432 MODULE_DEVICE_TABLE(input, evdev_ids);
1433
1434 static struct input_handler evdev_handler = {
1435         .event          = evdev_event,
1436         .events         = evdev_events,
1437         .connect        = evdev_connect,
1438         .disconnect     = evdev_disconnect,
1439         .legacy_minors  = true,
1440         .minor          = EVDEV_MINOR_BASE,
1441         .name           = "evdev",
1442         .id_table       = evdev_ids,
1443 };
1444
1445 static int __init evdev_init(void)
1446 {
1447         return input_register_handler(&evdev_handler);
1448 }
1449
1450 static void __exit evdev_exit(void)
1451 {
1452         input_unregister_handler(&evdev_handler);
1453 }
1454
1455 module_init(evdev_init);
1456 module_exit(evdev_exit);
1457
1458 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1459 MODULE_DESCRIPTION("Input driver event char devices");
1460 MODULE_LICENSE("GPL");