Linux 5.3-rc4
[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 enum evdev_clock_type {
29         EV_CLK_REAL = 0,
30         EV_CLK_MONO,
31         EV_CLK_BOOT,
32         EV_CLK_MAX
33 };
34
35 struct evdev {
36         int open;
37         struct input_handle handle;
38         wait_queue_head_t wait;
39         struct evdev_client __rcu *grab;
40         struct list_head client_list;
41         spinlock_t client_lock; /* protects client_list */
42         struct mutex mutex;
43         struct device dev;
44         struct cdev cdev;
45         bool exist;
46 };
47
48 struct evdev_client {
49         unsigned int head;
50         unsigned int tail;
51         unsigned int packet_head; /* [future] position of the first element of next packet */
52         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
53         struct fasync_struct *fasync;
54         struct evdev *evdev;
55         struct list_head node;
56         unsigned int clk_type;
57         bool revoked;
58         unsigned long *evmasks[EV_CNT];
59         unsigned int bufsize;
60         struct input_event buffer[];
61 };
62
63 static size_t evdev_get_mask_cnt(unsigned int type)
64 {
65         static const size_t counts[EV_CNT] = {
66                 /* EV_SYN==0 is EV_CNT, _not_ SYN_CNT, see EVIOCGBIT */
67                 [EV_SYN]        = EV_CNT,
68                 [EV_KEY]        = KEY_CNT,
69                 [EV_REL]        = REL_CNT,
70                 [EV_ABS]        = ABS_CNT,
71                 [EV_MSC]        = MSC_CNT,
72                 [EV_SW]         = SW_CNT,
73                 [EV_LED]        = LED_CNT,
74                 [EV_SND]        = SND_CNT,
75                 [EV_FF]         = FF_CNT,
76         };
77
78         return (type < EV_CNT) ? counts[type] : 0;
79 }
80
81 /* requires the buffer lock to be held */
82 static bool __evdev_is_filtered(struct evdev_client *client,
83                                 unsigned int type,
84                                 unsigned int code)
85 {
86         unsigned long *mask;
87         size_t cnt;
88
89         /* EV_SYN and unknown codes are never filtered */
90         if (type == EV_SYN || type >= EV_CNT)
91                 return false;
92
93         /* first test whether the type is filtered */
94         mask = client->evmasks[0];
95         if (mask && !test_bit(type, mask))
96                 return true;
97
98         /* unknown values are never filtered */
99         cnt = evdev_get_mask_cnt(type);
100         if (!cnt || code >= cnt)
101                 return false;
102
103         mask = client->evmasks[type];
104         return mask && !test_bit(code, mask);
105 }
106
107 /* flush queued events of type @type, caller must hold client->buffer_lock */
108 static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
109 {
110         unsigned int i, head, num;
111         unsigned int mask = client->bufsize - 1;
112         bool is_report;
113         struct input_event *ev;
114
115         BUG_ON(type == EV_SYN);
116
117         head = client->tail;
118         client->packet_head = client->tail;
119
120         /* init to 1 so a leading SYN_REPORT will not be dropped */
121         num = 1;
122
123         for (i = client->tail; i != client->head; i = (i + 1) & mask) {
124                 ev = &client->buffer[i];
125                 is_report = ev->type == EV_SYN && ev->code == SYN_REPORT;
126
127                 if (ev->type == type) {
128                         /* drop matched entry */
129                         continue;
130                 } else if (is_report && !num) {
131                         /* drop empty SYN_REPORT groups */
132                         continue;
133                 } else if (head != i) {
134                         /* move entry to fill the gap */
135                         client->buffer[head] = *ev;
136                 }
137
138                 num++;
139                 head = (head + 1) & mask;
140
141                 if (is_report) {
142                         num = 0;
143                         client->packet_head = head;
144                 }
145         }
146
147         client->head = head;
148 }
149
150 static void __evdev_queue_syn_dropped(struct evdev_client *client)
151 {
152         struct input_event ev;
153         ktime_t time;
154         struct timespec64 ts;
155
156         time = client->clk_type == EV_CLK_REAL ?
157                         ktime_get_real() :
158                         client->clk_type == EV_CLK_MONO ?
159                                 ktime_get() :
160                                 ktime_get_boottime();
161
162         ts = ktime_to_timespec64(time);
163         ev.input_event_sec = ts.tv_sec;
164         ev.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
165         ev.type = EV_SYN;
166         ev.code = SYN_DROPPED;
167         ev.value = 0;
168
169         client->buffer[client->head++] = ev;
170         client->head &= client->bufsize - 1;
171
172         if (unlikely(client->head == client->tail)) {
173                 /* drop queue but keep our SYN_DROPPED event */
174                 client->tail = (client->head - 1) & (client->bufsize - 1);
175                 client->packet_head = client->tail;
176         }
177 }
178
179 static void evdev_queue_syn_dropped(struct evdev_client *client)
180 {
181         unsigned long flags;
182
183         spin_lock_irqsave(&client->buffer_lock, flags);
184         __evdev_queue_syn_dropped(client);
185         spin_unlock_irqrestore(&client->buffer_lock, flags);
186 }
187
188 static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid)
189 {
190         unsigned long flags;
191         unsigned int clk_type;
192
193         switch (clkid) {
194
195         case CLOCK_REALTIME:
196                 clk_type = EV_CLK_REAL;
197                 break;
198         case CLOCK_MONOTONIC:
199                 clk_type = EV_CLK_MONO;
200                 break;
201         case CLOCK_BOOTTIME:
202                 clk_type = EV_CLK_BOOT;
203                 break;
204         default:
205                 return -EINVAL;
206         }
207
208         if (client->clk_type != clk_type) {
209                 client->clk_type = clk_type;
210
211                 /*
212                  * Flush pending events and queue SYN_DROPPED event,
213                  * but only if the queue is not empty.
214                  */
215                 spin_lock_irqsave(&client->buffer_lock, flags);
216
217                 if (client->head != client->tail) {
218                         client->packet_head = client->head = client->tail;
219                         __evdev_queue_syn_dropped(client);
220                 }
221
222                 spin_unlock_irqrestore(&client->buffer_lock, flags);
223         }
224
225         return 0;
226 }
227
228 static void __pass_event(struct evdev_client *client,
229                          const struct input_event *event)
230 {
231         client->buffer[client->head++] = *event;
232         client->head &= client->bufsize - 1;
233
234         if (unlikely(client->head == client->tail)) {
235                 /*
236                  * This effectively "drops" all unconsumed events, leaving
237                  * EV_SYN/SYN_DROPPED plus the newest event in the queue.
238                  */
239                 client->tail = (client->head - 2) & (client->bufsize - 1);
240
241                 client->buffer[client->tail].input_event_sec =
242                                                 event->input_event_sec;
243                 client->buffer[client->tail].input_event_usec =
244                                                 event->input_event_usec;
245                 client->buffer[client->tail].type = EV_SYN;
246                 client->buffer[client->tail].code = SYN_DROPPED;
247                 client->buffer[client->tail].value = 0;
248
249                 client->packet_head = client->tail;
250         }
251
252         if (event->type == EV_SYN && event->code == SYN_REPORT) {
253                 client->packet_head = client->head;
254                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
255         }
256 }
257
258 static void evdev_pass_values(struct evdev_client *client,
259                         const struct input_value *vals, unsigned int count,
260                         ktime_t *ev_time)
261 {
262         struct evdev *evdev = client->evdev;
263         const struct input_value *v;
264         struct input_event event;
265         struct timespec64 ts;
266         bool wakeup = false;
267
268         if (client->revoked)
269                 return;
270
271         ts = ktime_to_timespec64(ev_time[client->clk_type]);
272         event.input_event_sec = ts.tv_sec;
273         event.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
274
275         /* Interrupts are disabled, just acquire the lock. */
276         spin_lock(&client->buffer_lock);
277
278         for (v = vals; v != vals + count; v++) {
279                 if (__evdev_is_filtered(client, v->type, v->code))
280                         continue;
281
282                 if (v->type == EV_SYN && v->code == SYN_REPORT) {
283                         /* drop empty SYN_REPORT */
284                         if (client->packet_head == client->head)
285                                 continue;
286
287                         wakeup = true;
288                 }
289
290                 event.type = v->type;
291                 event.code = v->code;
292                 event.value = v->value;
293                 __pass_event(client, &event);
294         }
295
296         spin_unlock(&client->buffer_lock);
297
298         if (wakeup)
299                 wake_up_interruptible(&evdev->wait);
300 }
301
302 /*
303  * Pass incoming events to all connected clients.
304  */
305 static void evdev_events(struct input_handle *handle,
306                          const struct input_value *vals, unsigned int count)
307 {
308         struct evdev *evdev = handle->private;
309         struct evdev_client *client;
310         ktime_t ev_time[EV_CLK_MAX];
311
312         ev_time[EV_CLK_MONO] = ktime_get();
313         ev_time[EV_CLK_REAL] = ktime_mono_to_real(ev_time[EV_CLK_MONO]);
314         ev_time[EV_CLK_BOOT] = ktime_mono_to_any(ev_time[EV_CLK_MONO],
315                                                  TK_OFFS_BOOT);
316
317         rcu_read_lock();
318
319         client = rcu_dereference(evdev->grab);
320
321         if (client)
322                 evdev_pass_values(client, vals, count, ev_time);
323         else
324                 list_for_each_entry_rcu(client, &evdev->client_list, node)
325                         evdev_pass_values(client, vals, count, ev_time);
326
327         rcu_read_unlock();
328 }
329
330 /*
331  * Pass incoming event to all connected clients.
332  */
333 static void evdev_event(struct input_handle *handle,
334                         unsigned int type, unsigned int code, int value)
335 {
336         struct input_value vals[] = { { type, code, value } };
337
338         evdev_events(handle, vals, 1);
339 }
340
341 static int evdev_fasync(int fd, struct file *file, int on)
342 {
343         struct evdev_client *client = file->private_data;
344
345         return fasync_helper(fd, file, on, &client->fasync);
346 }
347
348 static int evdev_flush(struct file *file, fl_owner_t id)
349 {
350         struct evdev_client *client = file->private_data;
351         struct evdev *evdev = client->evdev;
352
353         mutex_lock(&evdev->mutex);
354
355         if (evdev->exist && !client->revoked)
356                 input_flush_device(&evdev->handle, file);
357
358         mutex_unlock(&evdev->mutex);
359         return 0;
360 }
361
362 static void evdev_free(struct device *dev)
363 {
364         struct evdev *evdev = container_of(dev, struct evdev, dev);
365
366         input_put_device(evdev->handle.dev);
367         kfree(evdev);
368 }
369
370 /*
371  * Grabs an event device (along with underlying input device).
372  * This function is called with evdev->mutex taken.
373  */
374 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
375 {
376         int error;
377
378         if (evdev->grab)
379                 return -EBUSY;
380
381         error = input_grab_device(&evdev->handle);
382         if (error)
383                 return error;
384
385         rcu_assign_pointer(evdev->grab, client);
386
387         return 0;
388 }
389
390 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
391 {
392         struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
393                                         lockdep_is_held(&evdev->mutex));
394
395         if (grab != client)
396                 return  -EINVAL;
397
398         rcu_assign_pointer(evdev->grab, NULL);
399         synchronize_rcu();
400         input_release_device(&evdev->handle);
401
402         return 0;
403 }
404
405 static void evdev_attach_client(struct evdev *evdev,
406                                 struct evdev_client *client)
407 {
408         spin_lock(&evdev->client_lock);
409         list_add_tail_rcu(&client->node, &evdev->client_list);
410         spin_unlock(&evdev->client_lock);
411 }
412
413 static void evdev_detach_client(struct evdev *evdev,
414                                 struct evdev_client *client)
415 {
416         spin_lock(&evdev->client_lock);
417         list_del_rcu(&client->node);
418         spin_unlock(&evdev->client_lock);
419         synchronize_rcu();
420 }
421
422 static int evdev_open_device(struct evdev *evdev)
423 {
424         int retval;
425
426         retval = mutex_lock_interruptible(&evdev->mutex);
427         if (retval)
428                 return retval;
429
430         if (!evdev->exist)
431                 retval = -ENODEV;
432         else if (!evdev->open++) {
433                 retval = input_open_device(&evdev->handle);
434                 if (retval)
435                         evdev->open--;
436         }
437
438         mutex_unlock(&evdev->mutex);
439         return retval;
440 }
441
442 static void evdev_close_device(struct evdev *evdev)
443 {
444         mutex_lock(&evdev->mutex);
445
446         if (evdev->exist && !--evdev->open)
447                 input_close_device(&evdev->handle);
448
449         mutex_unlock(&evdev->mutex);
450 }
451
452 /*
453  * Wake up users waiting for IO so they can disconnect from
454  * dead device.
455  */
456 static void evdev_hangup(struct evdev *evdev)
457 {
458         struct evdev_client *client;
459
460         spin_lock(&evdev->client_lock);
461         list_for_each_entry(client, &evdev->client_list, node)
462                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
463         spin_unlock(&evdev->client_lock);
464
465         wake_up_interruptible(&evdev->wait);
466 }
467
468 static int evdev_release(struct inode *inode, struct file *file)
469 {
470         struct evdev_client *client = file->private_data;
471         struct evdev *evdev = client->evdev;
472         unsigned int i;
473
474         mutex_lock(&evdev->mutex);
475         evdev_ungrab(evdev, client);
476         mutex_unlock(&evdev->mutex);
477
478         evdev_detach_client(evdev, client);
479
480         for (i = 0; i < EV_CNT; ++i)
481                 bitmap_free(client->evmasks[i]);
482
483         kvfree(client);
484
485         evdev_close_device(evdev);
486
487         return 0;
488 }
489
490 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
491 {
492         unsigned int n_events =
493                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
494                     EVDEV_MIN_BUFFER_SIZE);
495
496         return roundup_pow_of_two(n_events);
497 }
498
499 static int evdev_open(struct inode *inode, struct file *file)
500 {
501         struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
502         unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
503         struct evdev_client *client;
504         int error;
505
506         client = kzalloc(struct_size(client, buffer, bufsize),
507                          GFP_KERNEL | __GFP_NOWARN);
508         if (!client)
509                 client = vzalloc(struct_size(client, buffer, bufsize));
510         if (!client)
511                 return -ENOMEM;
512
513         client->bufsize = bufsize;
514         spin_lock_init(&client->buffer_lock);
515         client->evdev = evdev;
516         evdev_attach_client(evdev, client);
517
518         error = evdev_open_device(evdev);
519         if (error)
520                 goto err_free_client;
521
522         file->private_data = client;
523         stream_open(inode, file);
524
525         return 0;
526
527  err_free_client:
528         evdev_detach_client(evdev, client);
529         kvfree(client);
530         return error;
531 }
532
533 static ssize_t evdev_write(struct file *file, const char __user *buffer,
534                            size_t count, loff_t *ppos)
535 {
536         struct evdev_client *client = file->private_data;
537         struct evdev *evdev = client->evdev;
538         struct input_event event;
539         int retval = 0;
540
541         if (count != 0 && count < input_event_size())
542                 return -EINVAL;
543
544         retval = mutex_lock_interruptible(&evdev->mutex);
545         if (retval)
546                 return retval;
547
548         if (!evdev->exist || client->revoked) {
549                 retval = -ENODEV;
550                 goto out;
551         }
552
553         while (retval + input_event_size() <= count) {
554
555                 if (input_event_from_user(buffer + retval, &event)) {
556                         retval = -EFAULT;
557                         goto out;
558                 }
559                 retval += input_event_size();
560
561                 input_inject_event(&evdev->handle,
562                                    event.type, event.code, event.value);
563                 cond_resched();
564         }
565
566  out:
567         mutex_unlock(&evdev->mutex);
568         return retval;
569 }
570
571 static int evdev_fetch_next_event(struct evdev_client *client,
572                                   struct input_event *event)
573 {
574         int have_event;
575
576         spin_lock_irq(&client->buffer_lock);
577
578         have_event = client->packet_head != client->tail;
579         if (have_event) {
580                 *event = client->buffer[client->tail++];
581                 client->tail &= client->bufsize - 1;
582         }
583
584         spin_unlock_irq(&client->buffer_lock);
585
586         return have_event;
587 }
588
589 static ssize_t evdev_read(struct file *file, char __user *buffer,
590                           size_t count, loff_t *ppos)
591 {
592         struct evdev_client *client = file->private_data;
593         struct evdev *evdev = client->evdev;
594         struct input_event event;
595         size_t read = 0;
596         int error;
597
598         if (count != 0 && count < input_event_size())
599                 return -EINVAL;
600
601         for (;;) {
602                 if (!evdev->exist || client->revoked)
603                         return -ENODEV;
604
605                 if (client->packet_head == client->tail &&
606                     (file->f_flags & O_NONBLOCK))
607                         return -EAGAIN;
608
609                 /*
610                  * count == 0 is special - no IO is done but we check
611                  * for error conditions (see above).
612                  */
613                 if (count == 0)
614                         break;
615
616                 while (read + input_event_size() <= count &&
617                        evdev_fetch_next_event(client, &event)) {
618
619                         if (input_event_to_user(buffer + read, &event))
620                                 return -EFAULT;
621
622                         read += input_event_size();
623                 }
624
625                 if (read)
626                         break;
627
628                 if (!(file->f_flags & O_NONBLOCK)) {
629                         error = wait_event_interruptible(evdev->wait,
630                                         client->packet_head != client->tail ||
631                                         !evdev->exist || client->revoked);
632                         if (error)
633                                 return error;
634                 }
635         }
636
637         return read;
638 }
639
640 /* No kernel lock - fine */
641 static __poll_t evdev_poll(struct file *file, poll_table *wait)
642 {
643         struct evdev_client *client = file->private_data;
644         struct evdev *evdev = client->evdev;
645         __poll_t mask;
646
647         poll_wait(file, &evdev->wait, wait);
648
649         if (evdev->exist && !client->revoked)
650                 mask = EPOLLOUT | EPOLLWRNORM;
651         else
652                 mask = EPOLLHUP | EPOLLERR;
653
654         if (client->packet_head != client->tail)
655                 mask |= EPOLLIN | EPOLLRDNORM;
656
657         return mask;
658 }
659
660 #ifdef CONFIG_COMPAT
661
662 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
663 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
664
665 #ifdef __BIG_ENDIAN
666 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
667                         unsigned int maxlen, void __user *p, int compat)
668 {
669         int len, i;
670
671         if (compat) {
672                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
673                 if (len > maxlen)
674                         len = maxlen;
675
676                 for (i = 0; i < len / sizeof(compat_long_t); i++)
677                         if (copy_to_user((compat_long_t __user *) p + i,
678                                          (compat_long_t *) bits +
679                                                 i + 1 - ((i % 2) << 1),
680                                          sizeof(compat_long_t)))
681                                 return -EFAULT;
682         } else {
683                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
684                 if (len > maxlen)
685                         len = maxlen;
686
687                 if (copy_to_user(p, bits, len))
688                         return -EFAULT;
689         }
690
691         return len;
692 }
693
694 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
695                           unsigned int maxlen, const void __user *p, int compat)
696 {
697         int len, i;
698
699         if (compat) {
700                 if (maxlen % sizeof(compat_long_t))
701                         return -EINVAL;
702
703                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
704                 if (len > maxlen)
705                         len = maxlen;
706
707                 for (i = 0; i < len / sizeof(compat_long_t); i++)
708                         if (copy_from_user((compat_long_t *) bits +
709                                                 i + 1 - ((i % 2) << 1),
710                                            (compat_long_t __user *) p + i,
711                                            sizeof(compat_long_t)))
712                                 return -EFAULT;
713                 if (i % 2)
714                         *((compat_long_t *) bits + i - 1) = 0;
715
716         } else {
717                 if (maxlen % sizeof(long))
718                         return -EINVAL;
719
720                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
721                 if (len > maxlen)
722                         len = maxlen;
723
724                 if (copy_from_user(bits, p, len))
725                         return -EFAULT;
726         }
727
728         return len;
729 }
730
731 #else
732
733 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
734                         unsigned int maxlen, void __user *p, int compat)
735 {
736         int len = compat ?
737                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
738                         BITS_TO_LONGS(maxbit) * sizeof(long);
739
740         if (len > maxlen)
741                 len = maxlen;
742
743         return copy_to_user(p, bits, len) ? -EFAULT : len;
744 }
745
746 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
747                           unsigned int maxlen, const void __user *p, int compat)
748 {
749         size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long);
750         int len;
751
752         if (maxlen % chunk_size)
753                 return -EINVAL;
754
755         len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);
756         len *= chunk_size;
757         if (len > maxlen)
758                 len = maxlen;
759
760         return copy_from_user(bits, p, len) ? -EFAULT : len;
761 }
762
763 #endif /* __BIG_ENDIAN */
764
765 #else
766
767 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
768                         unsigned int maxlen, void __user *p, int compat)
769 {
770         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
771
772         if (len > maxlen)
773                 len = maxlen;
774
775         return copy_to_user(p, bits, len) ? -EFAULT : len;
776 }
777
778 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
779                           unsigned int maxlen, const void __user *p, int compat)
780 {
781         int len;
782
783         if (maxlen % sizeof(long))
784                 return -EINVAL;
785
786         len = BITS_TO_LONGS(maxbit) * sizeof(long);
787         if (len > maxlen)
788                 len = maxlen;
789
790         return copy_from_user(bits, p, len) ? -EFAULT : len;
791 }
792
793 #endif /* CONFIG_COMPAT */
794
795 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
796 {
797         int len;
798
799         if (!str)
800                 return -ENOENT;
801
802         len = strlen(str) + 1;
803         if (len > maxlen)
804                 len = maxlen;
805
806         return copy_to_user(p, str, len) ? -EFAULT : len;
807 }
808
809 static int handle_eviocgbit(struct input_dev *dev,
810                             unsigned int type, unsigned int size,
811                             void __user *p, int compat_mode)
812 {
813         unsigned long *bits;
814         int len;
815
816         switch (type) {
817
818         case      0: bits = dev->evbit;  len = EV_MAX;  break;
819         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
820         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
821         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
822         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
823         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
824         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
825         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
826         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
827         default: return -EINVAL;
828         }
829
830         return bits_to_user(bits, len, size, p, compat_mode);
831 }
832
833 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
834 {
835         struct input_keymap_entry ke = {
836                 .len    = sizeof(unsigned int),
837                 .flags  = 0,
838         };
839         int __user *ip = (int __user *)p;
840         int error;
841
842         /* legacy case */
843         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
844                 return -EFAULT;
845
846         error = input_get_keycode(dev, &ke);
847         if (error)
848                 return error;
849
850         if (put_user(ke.keycode, ip + 1))
851                 return -EFAULT;
852
853         return 0;
854 }
855
856 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
857 {
858         struct input_keymap_entry ke;
859         int error;
860
861         if (copy_from_user(&ke, p, sizeof(ke)))
862                 return -EFAULT;
863
864         error = input_get_keycode(dev, &ke);
865         if (error)
866                 return error;
867
868         if (copy_to_user(p, &ke, sizeof(ke)))
869                 return -EFAULT;
870
871         return 0;
872 }
873
874 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
875 {
876         struct input_keymap_entry ke = {
877                 .len    = sizeof(unsigned int),
878                 .flags  = 0,
879         };
880         int __user *ip = (int __user *)p;
881
882         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
883                 return -EFAULT;
884
885         if (get_user(ke.keycode, ip + 1))
886                 return -EFAULT;
887
888         return input_set_keycode(dev, &ke);
889 }
890
891 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
892 {
893         struct input_keymap_entry ke;
894
895         if (copy_from_user(&ke, p, sizeof(ke)))
896                 return -EFAULT;
897
898         if (ke.len > sizeof(ke.scancode))
899                 return -EINVAL;
900
901         return input_set_keycode(dev, &ke);
902 }
903
904 /*
905  * If we transfer state to the user, we should flush all pending events
906  * of the same type from the client's queue. Otherwise, they might end up
907  * with duplicate events, which can screw up client's state tracking.
908  * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
909  * event so user-space will notice missing events.
910  *
911  * LOCKING:
912  * We need to take event_lock before buffer_lock to avoid dead-locks. But we
913  * need the even_lock only to guarantee consistent state. We can safely release
914  * it while flushing the queue. This allows input-core to handle filters while
915  * we flush the queue.
916  */
917 static int evdev_handle_get_val(struct evdev_client *client,
918                                 struct input_dev *dev, unsigned int type,
919                                 unsigned long *bits, unsigned int maxbit,
920                                 unsigned int maxlen, void __user *p,
921                                 int compat)
922 {
923         int ret;
924         unsigned long *mem;
925
926         mem = bitmap_alloc(maxbit, GFP_KERNEL);
927         if (!mem)
928                 return -ENOMEM;
929
930         spin_lock_irq(&dev->event_lock);
931         spin_lock(&client->buffer_lock);
932
933         bitmap_copy(mem, bits, maxbit);
934
935         spin_unlock(&dev->event_lock);
936
937         __evdev_flush_queue(client, type);
938
939         spin_unlock_irq(&client->buffer_lock);
940
941         ret = bits_to_user(mem, maxbit, maxlen, p, compat);
942         if (ret < 0)
943                 evdev_queue_syn_dropped(client);
944
945         bitmap_free(mem);
946
947         return ret;
948 }
949
950 static int evdev_handle_mt_request(struct input_dev *dev,
951                                    unsigned int size,
952                                    int __user *ip)
953 {
954         const struct input_mt *mt = dev->mt;
955         unsigned int code;
956         int max_slots;
957         int i;
958
959         if (get_user(code, &ip[0]))
960                 return -EFAULT;
961         if (!mt || !input_is_mt_value(code))
962                 return -EINVAL;
963
964         max_slots = (size - sizeof(__u32)) / sizeof(__s32);
965         for (i = 0; i < mt->num_slots && i < max_slots; i++) {
966                 int value = input_mt_get_value(&mt->slots[i], code);
967                 if (put_user(value, &ip[1 + i]))
968                         return -EFAULT;
969         }
970
971         return 0;
972 }
973
974 static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
975                         struct file *file)
976 {
977         client->revoked = true;
978         evdev_ungrab(evdev, client);
979         input_flush_device(&evdev->handle, file);
980         wake_up_interruptible(&evdev->wait);
981
982         return 0;
983 }
984
985 /* must be called with evdev-mutex held */
986 static int evdev_set_mask(struct evdev_client *client,
987                           unsigned int type,
988                           const void __user *codes,
989                           u32 codes_size,
990                           int compat)
991 {
992         unsigned long flags, *mask, *oldmask;
993         size_t cnt;
994         int error;
995
996         /* we allow unknown types and 'codes_size > size' for forward-compat */
997         cnt = evdev_get_mask_cnt(type);
998         if (!cnt)
999                 return 0;
1000
1001         mask = bitmap_zalloc(cnt, GFP_KERNEL);
1002         if (!mask)
1003                 return -ENOMEM;
1004
1005         error = bits_from_user(mask, cnt - 1, codes_size, codes, compat);
1006         if (error < 0) {
1007                 bitmap_free(mask);
1008                 return error;
1009         }
1010
1011         spin_lock_irqsave(&client->buffer_lock, flags);
1012         oldmask = client->evmasks[type];
1013         client->evmasks[type] = mask;
1014         spin_unlock_irqrestore(&client->buffer_lock, flags);
1015
1016         bitmap_free(oldmask);
1017
1018         return 0;
1019 }
1020
1021 /* must be called with evdev-mutex held */
1022 static int evdev_get_mask(struct evdev_client *client,
1023                           unsigned int type,
1024                           void __user *codes,
1025                           u32 codes_size,
1026                           int compat)
1027 {
1028         unsigned long *mask;
1029         size_t cnt, size, xfer_size;
1030         int i;
1031         int error;
1032
1033         /* we allow unknown types and 'codes_size > size' for forward-compat */
1034         cnt = evdev_get_mask_cnt(type);
1035         size = sizeof(unsigned long) * BITS_TO_LONGS(cnt);
1036         xfer_size = min_t(size_t, codes_size, size);
1037
1038         if (cnt > 0) {
1039                 mask = client->evmasks[type];
1040                 if (mask) {
1041                         error = bits_to_user(mask, cnt - 1,
1042                                              xfer_size, codes, compat);
1043                         if (error < 0)
1044                                 return error;
1045                 } else {
1046                         /* fake mask with all bits set */
1047                         for (i = 0; i < xfer_size; i++)
1048                                 if (put_user(0xffU, (u8 __user *)codes + i))
1049                                         return -EFAULT;
1050                 }
1051         }
1052
1053         if (xfer_size < codes_size)
1054                 if (clear_user(codes + xfer_size, codes_size - xfer_size))
1055                         return -EFAULT;
1056
1057         return 0;
1058 }
1059
1060 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
1061                            void __user *p, int compat_mode)
1062 {
1063         struct evdev_client *client = file->private_data;
1064         struct evdev *evdev = client->evdev;
1065         struct input_dev *dev = evdev->handle.dev;
1066         struct input_absinfo abs;
1067         struct input_mask mask;
1068         struct ff_effect effect;
1069         int __user *ip = (int __user *)p;
1070         unsigned int i, t, u, v;
1071         unsigned int size;
1072         int error;
1073
1074         /* First we check for fixed-length commands */
1075         switch (cmd) {
1076
1077         case EVIOCGVERSION:
1078                 return put_user(EV_VERSION, ip);
1079
1080         case EVIOCGID:
1081                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
1082                         return -EFAULT;
1083                 return 0;
1084
1085         case EVIOCGREP:
1086                 if (!test_bit(EV_REP, dev->evbit))
1087                         return -ENOSYS;
1088                 if (put_user(dev->rep[REP_DELAY], ip))
1089                         return -EFAULT;
1090                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
1091                         return -EFAULT;
1092                 return 0;
1093
1094         case EVIOCSREP:
1095                 if (!test_bit(EV_REP, dev->evbit))
1096                         return -ENOSYS;
1097                 if (get_user(u, ip))
1098                         return -EFAULT;
1099                 if (get_user(v, ip + 1))
1100                         return -EFAULT;
1101
1102                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
1103                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
1104
1105                 return 0;
1106
1107         case EVIOCRMFF:
1108                 return input_ff_erase(dev, (int)(unsigned long) p, file);
1109
1110         case EVIOCGEFFECTS:
1111                 i = test_bit(EV_FF, dev->evbit) ?
1112                                 dev->ff->max_effects : 0;
1113                 if (put_user(i, ip))
1114                         return -EFAULT;
1115                 return 0;
1116
1117         case EVIOCGRAB:
1118                 if (p)
1119                         return evdev_grab(evdev, client);
1120                 else
1121                         return evdev_ungrab(evdev, client);
1122
1123         case EVIOCREVOKE:
1124                 if (p)
1125                         return -EINVAL;
1126                 else
1127                         return evdev_revoke(evdev, client, file);
1128
1129         case EVIOCGMASK: {
1130                 void __user *codes_ptr;
1131
1132                 if (copy_from_user(&mask, p, sizeof(mask)))
1133                         return -EFAULT;
1134
1135                 codes_ptr = (void __user *)(unsigned long)mask.codes_ptr;
1136                 return evdev_get_mask(client,
1137                                       mask.type, codes_ptr, mask.codes_size,
1138                                       compat_mode);
1139         }
1140
1141         case EVIOCSMASK: {
1142                 const void __user *codes_ptr;
1143
1144                 if (copy_from_user(&mask, p, sizeof(mask)))
1145                         return -EFAULT;
1146
1147                 codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr;
1148                 return evdev_set_mask(client,
1149                                       mask.type, codes_ptr, mask.codes_size,
1150                                       compat_mode);
1151         }
1152
1153         case EVIOCSCLOCKID:
1154                 if (copy_from_user(&i, p, sizeof(unsigned int)))
1155                         return -EFAULT;
1156
1157                 return evdev_set_clk_type(client, i);
1158
1159         case EVIOCGKEYCODE:
1160                 return evdev_handle_get_keycode(dev, p);
1161
1162         case EVIOCSKEYCODE:
1163                 return evdev_handle_set_keycode(dev, p);
1164
1165         case EVIOCGKEYCODE_V2:
1166                 return evdev_handle_get_keycode_v2(dev, p);
1167
1168         case EVIOCSKEYCODE_V2:
1169                 return evdev_handle_set_keycode_v2(dev, p);
1170         }
1171
1172         size = _IOC_SIZE(cmd);
1173
1174         /* Now check variable-length commands */
1175 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
1176         switch (EVIOC_MASK_SIZE(cmd)) {
1177
1178         case EVIOCGPROP(0):
1179                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
1180                                     size, p, compat_mode);
1181
1182         case EVIOCGMTSLOTS(0):
1183                 return evdev_handle_mt_request(dev, size, ip);
1184
1185         case EVIOCGKEY(0):
1186                 return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
1187                                             KEY_MAX, size, p, compat_mode);
1188
1189         case EVIOCGLED(0):
1190                 return evdev_handle_get_val(client, dev, EV_LED, dev->led,
1191                                             LED_MAX, size, p, compat_mode);
1192
1193         case EVIOCGSND(0):
1194                 return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
1195                                             SND_MAX, size, p, compat_mode);
1196
1197         case EVIOCGSW(0):
1198                 return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
1199                                             SW_MAX, size, p, compat_mode);
1200
1201         case EVIOCGNAME(0):
1202                 return str_to_user(dev->name, size, p);
1203
1204         case EVIOCGPHYS(0):
1205                 return str_to_user(dev->phys, size, p);
1206
1207         case EVIOCGUNIQ(0):
1208                 return str_to_user(dev->uniq, size, p);
1209
1210         case EVIOC_MASK_SIZE(EVIOCSFF):
1211                 if (input_ff_effect_from_user(p, size, &effect))
1212                         return -EFAULT;
1213
1214                 error = input_ff_upload(dev, &effect, file);
1215                 if (error)
1216                         return error;
1217
1218                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
1219                         return -EFAULT;
1220
1221                 return 0;
1222         }
1223
1224         /* Multi-number variable-length handlers */
1225         if (_IOC_TYPE(cmd) != 'E')
1226                 return -EINVAL;
1227
1228         if (_IOC_DIR(cmd) == _IOC_READ) {
1229
1230                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
1231                         return handle_eviocgbit(dev,
1232                                                 _IOC_NR(cmd) & EV_MAX, size,
1233                                                 p, compat_mode);
1234
1235                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1236
1237                         if (!dev->absinfo)
1238                                 return -EINVAL;
1239
1240                         t = _IOC_NR(cmd) & ABS_MAX;
1241                         abs = dev->absinfo[t];
1242
1243                         if (copy_to_user(p, &abs, min_t(size_t,
1244                                         size, sizeof(struct input_absinfo))))
1245                                 return -EFAULT;
1246
1247                         return 0;
1248                 }
1249         }
1250
1251         if (_IOC_DIR(cmd) == _IOC_WRITE) {
1252
1253                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1254
1255                         if (!dev->absinfo)
1256                                 return -EINVAL;
1257
1258                         t = _IOC_NR(cmd) & ABS_MAX;
1259
1260                         if (copy_from_user(&abs, p, min_t(size_t,
1261                                         size, sizeof(struct input_absinfo))))
1262                                 return -EFAULT;
1263
1264                         if (size < sizeof(struct input_absinfo))
1265                                 abs.resolution = 0;
1266
1267                         /* We can't change number of reserved MT slots */
1268                         if (t == ABS_MT_SLOT)
1269                                 return -EINVAL;
1270
1271                         /*
1272                          * Take event lock to ensure that we are not
1273                          * changing device parameters in the middle
1274                          * of event.
1275                          */
1276                         spin_lock_irq(&dev->event_lock);
1277                         dev->absinfo[t] = abs;
1278                         spin_unlock_irq(&dev->event_lock);
1279
1280                         return 0;
1281                 }
1282         }
1283
1284         return -EINVAL;
1285 }
1286
1287 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1288                                 void __user *p, int compat_mode)
1289 {
1290         struct evdev_client *client = file->private_data;
1291         struct evdev *evdev = client->evdev;
1292         int retval;
1293
1294         retval = mutex_lock_interruptible(&evdev->mutex);
1295         if (retval)
1296                 return retval;
1297
1298         if (!evdev->exist || client->revoked) {
1299                 retval = -ENODEV;
1300                 goto out;
1301         }
1302
1303         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1304
1305  out:
1306         mutex_unlock(&evdev->mutex);
1307         return retval;
1308 }
1309
1310 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1311 {
1312         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1313 }
1314
1315 #ifdef CONFIG_COMPAT
1316 static long evdev_ioctl_compat(struct file *file,
1317                                 unsigned int cmd, unsigned long arg)
1318 {
1319         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1320 }
1321 #endif
1322
1323 static const struct file_operations evdev_fops = {
1324         .owner          = THIS_MODULE,
1325         .read           = evdev_read,
1326         .write          = evdev_write,
1327         .poll           = evdev_poll,
1328         .open           = evdev_open,
1329         .release        = evdev_release,
1330         .unlocked_ioctl = evdev_ioctl,
1331 #ifdef CONFIG_COMPAT
1332         .compat_ioctl   = evdev_ioctl_compat,
1333 #endif
1334         .fasync         = evdev_fasync,
1335         .flush          = evdev_flush,
1336         .llseek         = no_llseek,
1337 };
1338
1339 /*
1340  * Mark device non-existent. This disables writes, ioctls and
1341  * prevents new users from opening the device. Already posted
1342  * blocking reads will stay, however new ones will fail.
1343  */
1344 static void evdev_mark_dead(struct evdev *evdev)
1345 {
1346         mutex_lock(&evdev->mutex);
1347         evdev->exist = false;
1348         mutex_unlock(&evdev->mutex);
1349 }
1350
1351 static void evdev_cleanup(struct evdev *evdev)
1352 {
1353         struct input_handle *handle = &evdev->handle;
1354
1355         evdev_mark_dead(evdev);
1356         evdev_hangup(evdev);
1357
1358         /* evdev is marked dead so no one else accesses evdev->open */
1359         if (evdev->open) {
1360                 input_flush_device(handle, NULL);
1361                 input_close_device(handle);
1362         }
1363 }
1364
1365 /*
1366  * Create new evdev device. Note that input core serializes calls
1367  * to connect and disconnect.
1368  */
1369 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1370                          const struct input_device_id *id)
1371 {
1372         struct evdev *evdev;
1373         int minor;
1374         int dev_no;
1375         int error;
1376
1377         minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1378         if (minor < 0) {
1379                 error = minor;
1380                 pr_err("failed to reserve new minor: %d\n", error);
1381                 return error;
1382         }
1383
1384         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1385         if (!evdev) {
1386                 error = -ENOMEM;
1387                 goto err_free_minor;
1388         }
1389
1390         INIT_LIST_HEAD(&evdev->client_list);
1391         spin_lock_init(&evdev->client_lock);
1392         mutex_init(&evdev->mutex);
1393         init_waitqueue_head(&evdev->wait);
1394         evdev->exist = true;
1395
1396         dev_no = minor;
1397         /* Normalize device number if it falls into legacy range */
1398         if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1399                 dev_no -= EVDEV_MINOR_BASE;
1400         dev_set_name(&evdev->dev, "event%d", dev_no);
1401
1402         evdev->handle.dev = input_get_device(dev);
1403         evdev->handle.name = dev_name(&evdev->dev);
1404         evdev->handle.handler = handler;
1405         evdev->handle.private = evdev;
1406
1407         evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1408         evdev->dev.class = &input_class;
1409         evdev->dev.parent = &dev->dev;
1410         evdev->dev.release = evdev_free;
1411         device_initialize(&evdev->dev);
1412
1413         error = input_register_handle(&evdev->handle);
1414         if (error)
1415                 goto err_free_evdev;
1416
1417         cdev_init(&evdev->cdev, &evdev_fops);
1418
1419         error = cdev_device_add(&evdev->cdev, &evdev->dev);
1420         if (error)
1421                 goto err_cleanup_evdev;
1422
1423         return 0;
1424
1425  err_cleanup_evdev:
1426         evdev_cleanup(evdev);
1427         input_unregister_handle(&evdev->handle);
1428  err_free_evdev:
1429         put_device(&evdev->dev);
1430  err_free_minor:
1431         input_free_minor(minor);
1432         return error;
1433 }
1434
1435 static void evdev_disconnect(struct input_handle *handle)
1436 {
1437         struct evdev *evdev = handle->private;
1438
1439         cdev_device_del(&evdev->cdev, &evdev->dev);
1440         evdev_cleanup(evdev);
1441         input_free_minor(MINOR(evdev->dev.devt));
1442         input_unregister_handle(handle);
1443         put_device(&evdev->dev);
1444 }
1445
1446 static const struct input_device_id evdev_ids[] = {
1447         { .driver_info = 1 },   /* Matches all devices */
1448         { },                    /* Terminating zero entry */
1449 };
1450
1451 MODULE_DEVICE_TABLE(input, evdev_ids);
1452
1453 static struct input_handler evdev_handler = {
1454         .event          = evdev_event,
1455         .events         = evdev_events,
1456         .connect        = evdev_connect,
1457         .disconnect     = evdev_disconnect,
1458         .legacy_minors  = true,
1459         .minor          = EVDEV_MINOR_BASE,
1460         .name           = "evdev",
1461         .id_table       = evdev_ids,
1462 };
1463
1464 static int __init evdev_init(void)
1465 {
1466         return input_register_handler(&evdev_handler);
1467 }
1468
1469 static void __exit evdev_exit(void)
1470 {
1471         input_unregister_handler(&evdev_handler);
1472 }
1473
1474 module_init(evdev_init);
1475 module_exit(evdev_exit);
1476
1477 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1478 MODULE_DESCRIPTION("Input driver event char devices");
1479 MODULE_LICENSE("GPL");