Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[sfrench/cifs-2.6.git] / drivers / input / evdev.c
1 /*
2  * Event char devices, giving access to raw input device events.
3  *
4  * Copyright (c) 1999-2002 Vojtech Pavlik
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License version 2 as published by
8  * the Free Software Foundation.
9  */
10
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13 #define EVDEV_MINOR_BASE        64
14 #define EVDEV_MINORS            32
15 #define EVDEV_MIN_BUFFER_SIZE   64U
16 #define EVDEV_BUF_PACKETS       8
17
18 #include <linux/poll.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/vmalloc.h>
22 #include <linux/mm.h>
23 #include <linux/module.h>
24 #include <linux/init.h>
25 #include <linux/input/mt.h>
26 #include <linux/major.h>
27 #include <linux/device.h>
28 #include <linux/cdev.h>
29 #include "input-compat.h"
30
31 enum evdev_clock_type {
32         EV_CLK_REAL = 0,
33         EV_CLK_MONO,
34         EV_CLK_BOOT,
35         EV_CLK_MAX
36 };
37
38 struct evdev {
39         int open;
40         struct input_handle handle;
41         wait_queue_head_t wait;
42         struct evdev_client __rcu *grab;
43         struct list_head client_list;
44         spinlock_t client_lock; /* protects client_list */
45         struct mutex mutex;
46         struct device dev;
47         struct cdev cdev;
48         bool exist;
49 };
50
51 struct evdev_client {
52         unsigned int head;
53         unsigned int tail;
54         unsigned int packet_head; /* [future] position of the first element of next packet */
55         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
56         struct fasync_struct *fasync;
57         struct evdev *evdev;
58         struct list_head node;
59         unsigned int clk_type;
60         bool revoked;
61         unsigned long *evmasks[EV_CNT];
62         unsigned int bufsize;
63         struct input_event buffer[];
64 };
65
66 static size_t evdev_get_mask_cnt(unsigned int type)
67 {
68         static const size_t counts[EV_CNT] = {
69                 /* EV_SYN==0 is EV_CNT, _not_ SYN_CNT, see EVIOCGBIT */
70                 [EV_SYN]        = EV_CNT,
71                 [EV_KEY]        = KEY_CNT,
72                 [EV_REL]        = REL_CNT,
73                 [EV_ABS]        = ABS_CNT,
74                 [EV_MSC]        = MSC_CNT,
75                 [EV_SW]         = SW_CNT,
76                 [EV_LED]        = LED_CNT,
77                 [EV_SND]        = SND_CNT,
78                 [EV_FF]         = FF_CNT,
79         };
80
81         return (type < EV_CNT) ? counts[type] : 0;
82 }
83
84 /* requires the buffer lock to be held */
85 static bool __evdev_is_filtered(struct evdev_client *client,
86                                 unsigned int type,
87                                 unsigned int code)
88 {
89         unsigned long *mask;
90         size_t cnt;
91
92         /* EV_SYN and unknown codes are never filtered */
93         if (type == EV_SYN || type >= EV_CNT)
94                 return false;
95
96         /* first test whether the type is filtered */
97         mask = client->evmasks[0];
98         if (mask && !test_bit(type, mask))
99                 return true;
100
101         /* unknown values are never filtered */
102         cnt = evdev_get_mask_cnt(type);
103         if (!cnt || code >= cnt)
104                 return false;
105
106         mask = client->evmasks[type];
107         return mask && !test_bit(code, mask);
108 }
109
110 /* flush queued events of type @type, caller must hold client->buffer_lock */
111 static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
112 {
113         unsigned int i, head, num;
114         unsigned int mask = client->bufsize - 1;
115         bool is_report;
116         struct input_event *ev;
117
118         BUG_ON(type == EV_SYN);
119
120         head = client->tail;
121         client->packet_head = client->tail;
122
123         /* init to 1 so a leading SYN_REPORT will not be dropped */
124         num = 1;
125
126         for (i = client->tail; i != client->head; i = (i + 1) & mask) {
127                 ev = &client->buffer[i];
128                 is_report = ev->type == EV_SYN && ev->code == SYN_REPORT;
129
130                 if (ev->type == type) {
131                         /* drop matched entry */
132                         continue;
133                 } else if (is_report && !num) {
134                         /* drop empty SYN_REPORT groups */
135                         continue;
136                 } else if (head != i) {
137                         /* move entry to fill the gap */
138                         client->buffer[head] = *ev;
139                 }
140
141                 num++;
142                 head = (head + 1) & mask;
143
144                 if (is_report) {
145                         num = 0;
146                         client->packet_head = head;
147                 }
148         }
149
150         client->head = head;
151 }
152
153 static void __evdev_queue_syn_dropped(struct evdev_client *client)
154 {
155         struct input_event ev;
156         ktime_t time;
157         struct timespec64 ts;
158
159         time = client->clk_type == EV_CLK_REAL ?
160                         ktime_get_real() :
161                         client->clk_type == EV_CLK_MONO ?
162                                 ktime_get() :
163                                 ktime_get_boottime();
164
165         ts = ktime_to_timespec64(time);
166         ev.input_event_sec = ts.tv_sec;
167         ev.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
168         ev.type = EV_SYN;
169         ev.code = SYN_DROPPED;
170         ev.value = 0;
171
172         client->buffer[client->head++] = ev;
173         client->head &= client->bufsize - 1;
174
175         if (unlikely(client->head == client->tail)) {
176                 /* drop queue but keep our SYN_DROPPED event */
177                 client->tail = (client->head - 1) & (client->bufsize - 1);
178                 client->packet_head = client->tail;
179         }
180 }
181
182 static void evdev_queue_syn_dropped(struct evdev_client *client)
183 {
184         unsigned long flags;
185
186         spin_lock_irqsave(&client->buffer_lock, flags);
187         __evdev_queue_syn_dropped(client);
188         spin_unlock_irqrestore(&client->buffer_lock, flags);
189 }
190
191 static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid)
192 {
193         unsigned long flags;
194         unsigned int clk_type;
195
196         switch (clkid) {
197
198         case CLOCK_REALTIME:
199                 clk_type = EV_CLK_REAL;
200                 break;
201         case CLOCK_MONOTONIC:
202                 clk_type = EV_CLK_MONO;
203                 break;
204         case CLOCK_BOOTTIME:
205                 clk_type = EV_CLK_BOOT;
206                 break;
207         default:
208                 return -EINVAL;
209         }
210
211         if (client->clk_type != clk_type) {
212                 client->clk_type = clk_type;
213
214                 /*
215                  * Flush pending events and queue SYN_DROPPED event,
216                  * but only if the queue is not empty.
217                  */
218                 spin_lock_irqsave(&client->buffer_lock, flags);
219
220                 if (client->head != client->tail) {
221                         client->packet_head = client->head = client->tail;
222                         __evdev_queue_syn_dropped(client);
223                 }
224
225                 spin_unlock_irqrestore(&client->buffer_lock, flags);
226         }
227
228         return 0;
229 }
230
231 static void __pass_event(struct evdev_client *client,
232                          const struct input_event *event)
233 {
234         client->buffer[client->head++] = *event;
235         client->head &= client->bufsize - 1;
236
237         if (unlikely(client->head == client->tail)) {
238                 /*
239                  * This effectively "drops" all unconsumed events, leaving
240                  * EV_SYN/SYN_DROPPED plus the newest event in the queue.
241                  */
242                 client->tail = (client->head - 2) & (client->bufsize - 1);
243
244                 client->buffer[client->tail].input_event_sec =
245                                                 event->input_event_sec;
246                 client->buffer[client->tail].input_event_usec =
247                                                 event->input_event_usec;
248                 client->buffer[client->tail].type = EV_SYN;
249                 client->buffer[client->tail].code = SYN_DROPPED;
250                 client->buffer[client->tail].value = 0;
251
252                 client->packet_head = client->tail;
253         }
254
255         if (event->type == EV_SYN && event->code == SYN_REPORT) {
256                 client->packet_head = client->head;
257                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
258         }
259 }
260
261 static void evdev_pass_values(struct evdev_client *client,
262                         const struct input_value *vals, unsigned int count,
263                         ktime_t *ev_time)
264 {
265         struct evdev *evdev = client->evdev;
266         const struct input_value *v;
267         struct input_event event;
268         struct timespec64 ts;
269         bool wakeup = false;
270
271         if (client->revoked)
272                 return;
273
274         ts = ktime_to_timespec64(ev_time[client->clk_type]);
275         event.input_event_sec = ts.tv_sec;
276         event.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
277
278         /* Interrupts are disabled, just acquire the lock. */
279         spin_lock(&client->buffer_lock);
280
281         for (v = vals; v != vals + count; v++) {
282                 if (__evdev_is_filtered(client, v->type, v->code))
283                         continue;
284
285                 if (v->type == EV_SYN && v->code == SYN_REPORT) {
286                         /* drop empty SYN_REPORT */
287                         if (client->packet_head == client->head)
288                                 continue;
289
290                         wakeup = true;
291                 }
292
293                 event.type = v->type;
294                 event.code = v->code;
295                 event.value = v->value;
296                 __pass_event(client, &event);
297         }
298
299         spin_unlock(&client->buffer_lock);
300
301         if (wakeup)
302                 wake_up_interruptible(&evdev->wait);
303 }
304
305 /*
306  * Pass incoming events to all connected clients.
307  */
308 static void evdev_events(struct input_handle *handle,
309                          const struct input_value *vals, unsigned int count)
310 {
311         struct evdev *evdev = handle->private;
312         struct evdev_client *client;
313         ktime_t ev_time[EV_CLK_MAX];
314
315         ev_time[EV_CLK_MONO] = ktime_get();
316         ev_time[EV_CLK_REAL] = ktime_mono_to_real(ev_time[EV_CLK_MONO]);
317         ev_time[EV_CLK_BOOT] = ktime_mono_to_any(ev_time[EV_CLK_MONO],
318                                                  TK_OFFS_BOOT);
319
320         rcu_read_lock();
321
322         client = rcu_dereference(evdev->grab);
323
324         if (client)
325                 evdev_pass_values(client, vals, count, ev_time);
326         else
327                 list_for_each_entry_rcu(client, &evdev->client_list, node)
328                         evdev_pass_values(client, vals, count, ev_time);
329
330         rcu_read_unlock();
331 }
332
333 /*
334  * Pass incoming event to all connected clients.
335  */
336 static void evdev_event(struct input_handle *handle,
337                         unsigned int type, unsigned int code, int value)
338 {
339         struct input_value vals[] = { { type, code, value } };
340
341         evdev_events(handle, vals, 1);
342 }
343
344 static int evdev_fasync(int fd, struct file *file, int on)
345 {
346         struct evdev_client *client = file->private_data;
347
348         return fasync_helper(fd, file, on, &client->fasync);
349 }
350
351 static int evdev_flush(struct file *file, fl_owner_t id)
352 {
353         struct evdev_client *client = file->private_data;
354         struct evdev *evdev = client->evdev;
355
356         mutex_lock(&evdev->mutex);
357
358         if (evdev->exist && !client->revoked)
359                 input_flush_device(&evdev->handle, file);
360
361         mutex_unlock(&evdev->mutex);
362         return 0;
363 }
364
365 static void evdev_free(struct device *dev)
366 {
367         struct evdev *evdev = container_of(dev, struct evdev, dev);
368
369         input_put_device(evdev->handle.dev);
370         kfree(evdev);
371 }
372
373 /*
374  * Grabs an event device (along with underlying input device).
375  * This function is called with evdev->mutex taken.
376  */
377 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
378 {
379         int error;
380
381         if (evdev->grab)
382                 return -EBUSY;
383
384         error = input_grab_device(&evdev->handle);
385         if (error)
386                 return error;
387
388         rcu_assign_pointer(evdev->grab, client);
389
390         return 0;
391 }
392
393 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
394 {
395         struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
396                                         lockdep_is_held(&evdev->mutex));
397
398         if (grab != client)
399                 return  -EINVAL;
400
401         rcu_assign_pointer(evdev->grab, NULL);
402         synchronize_rcu();
403         input_release_device(&evdev->handle);
404
405         return 0;
406 }
407
408 static void evdev_attach_client(struct evdev *evdev,
409                                 struct evdev_client *client)
410 {
411         spin_lock(&evdev->client_lock);
412         list_add_tail_rcu(&client->node, &evdev->client_list);
413         spin_unlock(&evdev->client_lock);
414 }
415
416 static void evdev_detach_client(struct evdev *evdev,
417                                 struct evdev_client *client)
418 {
419         spin_lock(&evdev->client_lock);
420         list_del_rcu(&client->node);
421         spin_unlock(&evdev->client_lock);
422         synchronize_rcu();
423 }
424
425 static int evdev_open_device(struct evdev *evdev)
426 {
427         int retval;
428
429         retval = mutex_lock_interruptible(&evdev->mutex);
430         if (retval)
431                 return retval;
432
433         if (!evdev->exist)
434                 retval = -ENODEV;
435         else if (!evdev->open++) {
436                 retval = input_open_device(&evdev->handle);
437                 if (retval)
438                         evdev->open--;
439         }
440
441         mutex_unlock(&evdev->mutex);
442         return retval;
443 }
444
445 static void evdev_close_device(struct evdev *evdev)
446 {
447         mutex_lock(&evdev->mutex);
448
449         if (evdev->exist && !--evdev->open)
450                 input_close_device(&evdev->handle);
451
452         mutex_unlock(&evdev->mutex);
453 }
454
455 /*
456  * Wake up users waiting for IO so they can disconnect from
457  * dead device.
458  */
459 static void evdev_hangup(struct evdev *evdev)
460 {
461         struct evdev_client *client;
462
463         spin_lock(&evdev->client_lock);
464         list_for_each_entry(client, &evdev->client_list, node)
465                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
466         spin_unlock(&evdev->client_lock);
467
468         wake_up_interruptible(&evdev->wait);
469 }
470
471 static int evdev_release(struct inode *inode, struct file *file)
472 {
473         struct evdev_client *client = file->private_data;
474         struct evdev *evdev = client->evdev;
475         unsigned int i;
476
477         mutex_lock(&evdev->mutex);
478         evdev_ungrab(evdev, client);
479         mutex_unlock(&evdev->mutex);
480
481         evdev_detach_client(evdev, client);
482
483         for (i = 0; i < EV_CNT; ++i)
484                 bitmap_free(client->evmasks[i]);
485
486         kvfree(client);
487
488         evdev_close_device(evdev);
489
490         return 0;
491 }
492
493 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
494 {
495         unsigned int n_events =
496                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
497                     EVDEV_MIN_BUFFER_SIZE);
498
499         return roundup_pow_of_two(n_events);
500 }
501
502 static int evdev_open(struct inode *inode, struct file *file)
503 {
504         struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
505         unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
506         struct evdev_client *client;
507         int error;
508
509         client = kzalloc(struct_size(client, buffer, bufsize),
510                          GFP_KERNEL | __GFP_NOWARN);
511         if (!client)
512                 client = vzalloc(struct_size(client, buffer, bufsize));
513         if (!client)
514                 return -ENOMEM;
515
516         client->bufsize = bufsize;
517         spin_lock_init(&client->buffer_lock);
518         client->evdev = evdev;
519         evdev_attach_client(evdev, client);
520
521         error = evdev_open_device(evdev);
522         if (error)
523                 goto err_free_client;
524
525         file->private_data = client;
526         stream_open(inode, file);
527
528         return 0;
529
530  err_free_client:
531         evdev_detach_client(evdev, client);
532         kvfree(client);
533         return error;
534 }
535
536 static ssize_t evdev_write(struct file *file, const char __user *buffer,
537                            size_t count, loff_t *ppos)
538 {
539         struct evdev_client *client = file->private_data;
540         struct evdev *evdev = client->evdev;
541         struct input_event event;
542         int retval = 0;
543
544         if (count != 0 && count < input_event_size())
545                 return -EINVAL;
546
547         retval = mutex_lock_interruptible(&evdev->mutex);
548         if (retval)
549                 return retval;
550
551         if (!evdev->exist || client->revoked) {
552                 retval = -ENODEV;
553                 goto out;
554         }
555
556         while (retval + input_event_size() <= count) {
557
558                 if (input_event_from_user(buffer + retval, &event)) {
559                         retval = -EFAULT;
560                         goto out;
561                 }
562                 retval += input_event_size();
563
564                 input_inject_event(&evdev->handle,
565                                    event.type, event.code, event.value);
566                 cond_resched();
567         }
568
569  out:
570         mutex_unlock(&evdev->mutex);
571         return retval;
572 }
573
574 static int evdev_fetch_next_event(struct evdev_client *client,
575                                   struct input_event *event)
576 {
577         int have_event;
578
579         spin_lock_irq(&client->buffer_lock);
580
581         have_event = client->packet_head != client->tail;
582         if (have_event) {
583                 *event = client->buffer[client->tail++];
584                 client->tail &= client->bufsize - 1;
585         }
586
587         spin_unlock_irq(&client->buffer_lock);
588
589         return have_event;
590 }
591
592 static ssize_t evdev_read(struct file *file, char __user *buffer,
593                           size_t count, loff_t *ppos)
594 {
595         struct evdev_client *client = file->private_data;
596         struct evdev *evdev = client->evdev;
597         struct input_event event;
598         size_t read = 0;
599         int error;
600
601         if (count != 0 && count < input_event_size())
602                 return -EINVAL;
603
604         for (;;) {
605                 if (!evdev->exist || client->revoked)
606                         return -ENODEV;
607
608                 if (client->packet_head == client->tail &&
609                     (file->f_flags & O_NONBLOCK))
610                         return -EAGAIN;
611
612                 /*
613                  * count == 0 is special - no IO is done but we check
614                  * for error conditions (see above).
615                  */
616                 if (count == 0)
617                         break;
618
619                 while (read + input_event_size() <= count &&
620                        evdev_fetch_next_event(client, &event)) {
621
622                         if (input_event_to_user(buffer + read, &event))
623                                 return -EFAULT;
624
625                         read += input_event_size();
626                 }
627
628                 if (read)
629                         break;
630
631                 if (!(file->f_flags & O_NONBLOCK)) {
632                         error = wait_event_interruptible(evdev->wait,
633                                         client->packet_head != client->tail ||
634                                         !evdev->exist || client->revoked);
635                         if (error)
636                                 return error;
637                 }
638         }
639
640         return read;
641 }
642
643 /* No kernel lock - fine */
644 static __poll_t evdev_poll(struct file *file, poll_table *wait)
645 {
646         struct evdev_client *client = file->private_data;
647         struct evdev *evdev = client->evdev;
648         __poll_t mask;
649
650         poll_wait(file, &evdev->wait, wait);
651
652         if (evdev->exist && !client->revoked)
653                 mask = EPOLLOUT | EPOLLWRNORM;
654         else
655                 mask = EPOLLHUP | EPOLLERR;
656
657         if (client->packet_head != client->tail)
658                 mask |= EPOLLIN | EPOLLRDNORM;
659
660         return mask;
661 }
662
663 #ifdef CONFIG_COMPAT
664
665 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
666 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
667
668 #ifdef __BIG_ENDIAN
669 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
670                         unsigned int maxlen, void __user *p, int compat)
671 {
672         int len, i;
673
674         if (compat) {
675                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
676                 if (len > maxlen)
677                         len = maxlen;
678
679                 for (i = 0; i < len / sizeof(compat_long_t); i++)
680                         if (copy_to_user((compat_long_t __user *) p + i,
681                                          (compat_long_t *) bits +
682                                                 i + 1 - ((i % 2) << 1),
683                                          sizeof(compat_long_t)))
684                                 return -EFAULT;
685         } else {
686                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
687                 if (len > maxlen)
688                         len = maxlen;
689
690                 if (copy_to_user(p, bits, len))
691                         return -EFAULT;
692         }
693
694         return len;
695 }
696
697 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
698                           unsigned int maxlen, const void __user *p, int compat)
699 {
700         int len, i;
701
702         if (compat) {
703                 if (maxlen % sizeof(compat_long_t))
704                         return -EINVAL;
705
706                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
707                 if (len > maxlen)
708                         len = maxlen;
709
710                 for (i = 0; i < len / sizeof(compat_long_t); i++)
711                         if (copy_from_user((compat_long_t *) bits +
712                                                 i + 1 - ((i % 2) << 1),
713                                            (compat_long_t __user *) p + i,
714                                            sizeof(compat_long_t)))
715                                 return -EFAULT;
716                 if (i % 2)
717                         *((compat_long_t *) bits + i - 1) = 0;
718
719         } else {
720                 if (maxlen % sizeof(long))
721                         return -EINVAL;
722
723                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
724                 if (len > maxlen)
725                         len = maxlen;
726
727                 if (copy_from_user(bits, p, len))
728                         return -EFAULT;
729         }
730
731         return len;
732 }
733
734 #else
735
736 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
737                         unsigned int maxlen, void __user *p, int compat)
738 {
739         int len = compat ?
740                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
741                         BITS_TO_LONGS(maxbit) * sizeof(long);
742
743         if (len > maxlen)
744                 len = maxlen;
745
746         return copy_to_user(p, bits, len) ? -EFAULT : len;
747 }
748
749 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
750                           unsigned int maxlen, const void __user *p, int compat)
751 {
752         size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long);
753         int len;
754
755         if (maxlen % chunk_size)
756                 return -EINVAL;
757
758         len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);
759         len *= chunk_size;
760         if (len > maxlen)
761                 len = maxlen;
762
763         return copy_from_user(bits, p, len) ? -EFAULT : len;
764 }
765
766 #endif /* __BIG_ENDIAN */
767
768 #else
769
770 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
771                         unsigned int maxlen, void __user *p, int compat)
772 {
773         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
774
775         if (len > maxlen)
776                 len = maxlen;
777
778         return copy_to_user(p, bits, len) ? -EFAULT : len;
779 }
780
781 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
782                           unsigned int maxlen, const void __user *p, int compat)
783 {
784         int len;
785
786         if (maxlen % sizeof(long))
787                 return -EINVAL;
788
789         len = BITS_TO_LONGS(maxbit) * sizeof(long);
790         if (len > maxlen)
791                 len = maxlen;
792
793         return copy_from_user(bits, p, len) ? -EFAULT : len;
794 }
795
796 #endif /* CONFIG_COMPAT */
797
798 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
799 {
800         int len;
801
802         if (!str)
803                 return -ENOENT;
804
805         len = strlen(str) + 1;
806         if (len > maxlen)
807                 len = maxlen;
808
809         return copy_to_user(p, str, len) ? -EFAULT : len;
810 }
811
812 static int handle_eviocgbit(struct input_dev *dev,
813                             unsigned int type, unsigned int size,
814                             void __user *p, int compat_mode)
815 {
816         unsigned long *bits;
817         int len;
818
819         switch (type) {
820
821         case      0: bits = dev->evbit;  len = EV_MAX;  break;
822         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
823         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
824         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
825         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
826         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
827         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
828         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
829         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
830         default: return -EINVAL;
831         }
832
833         return bits_to_user(bits, len, size, p, compat_mode);
834 }
835
836 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
837 {
838         struct input_keymap_entry ke = {
839                 .len    = sizeof(unsigned int),
840                 .flags  = 0,
841         };
842         int __user *ip = (int __user *)p;
843         int error;
844
845         /* legacy case */
846         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
847                 return -EFAULT;
848
849         error = input_get_keycode(dev, &ke);
850         if (error)
851                 return error;
852
853         if (put_user(ke.keycode, ip + 1))
854                 return -EFAULT;
855
856         return 0;
857 }
858
859 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
860 {
861         struct input_keymap_entry ke;
862         int error;
863
864         if (copy_from_user(&ke, p, sizeof(ke)))
865                 return -EFAULT;
866
867         error = input_get_keycode(dev, &ke);
868         if (error)
869                 return error;
870
871         if (copy_to_user(p, &ke, sizeof(ke)))
872                 return -EFAULT;
873
874         return 0;
875 }
876
877 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
878 {
879         struct input_keymap_entry ke = {
880                 .len    = sizeof(unsigned int),
881                 .flags  = 0,
882         };
883         int __user *ip = (int __user *)p;
884
885         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
886                 return -EFAULT;
887
888         if (get_user(ke.keycode, ip + 1))
889                 return -EFAULT;
890
891         return input_set_keycode(dev, &ke);
892 }
893
894 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
895 {
896         struct input_keymap_entry ke;
897
898         if (copy_from_user(&ke, p, sizeof(ke)))
899                 return -EFAULT;
900
901         if (ke.len > sizeof(ke.scancode))
902                 return -EINVAL;
903
904         return input_set_keycode(dev, &ke);
905 }
906
907 /*
908  * If we transfer state to the user, we should flush all pending events
909  * of the same type from the client's queue. Otherwise, they might end up
910  * with duplicate events, which can screw up client's state tracking.
911  * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
912  * event so user-space will notice missing events.
913  *
914  * LOCKING:
915  * We need to take event_lock before buffer_lock to avoid dead-locks. But we
916  * need the even_lock only to guarantee consistent state. We can safely release
917  * it while flushing the queue. This allows input-core to handle filters while
918  * we flush the queue.
919  */
920 static int evdev_handle_get_val(struct evdev_client *client,
921                                 struct input_dev *dev, unsigned int type,
922                                 unsigned long *bits, unsigned int maxbit,
923                                 unsigned int maxlen, void __user *p,
924                                 int compat)
925 {
926         int ret;
927         unsigned long *mem;
928
929         mem = bitmap_alloc(maxbit, GFP_KERNEL);
930         if (!mem)
931                 return -ENOMEM;
932
933         spin_lock_irq(&dev->event_lock);
934         spin_lock(&client->buffer_lock);
935
936         bitmap_copy(mem, bits, maxbit);
937
938         spin_unlock(&dev->event_lock);
939
940         __evdev_flush_queue(client, type);
941
942         spin_unlock_irq(&client->buffer_lock);
943
944         ret = bits_to_user(mem, maxbit, maxlen, p, compat);
945         if (ret < 0)
946                 evdev_queue_syn_dropped(client);
947
948         bitmap_free(mem);
949
950         return ret;
951 }
952
953 static int evdev_handle_mt_request(struct input_dev *dev,
954                                    unsigned int size,
955                                    int __user *ip)
956 {
957         const struct input_mt *mt = dev->mt;
958         unsigned int code;
959         int max_slots;
960         int i;
961
962         if (get_user(code, &ip[0]))
963                 return -EFAULT;
964         if (!mt || !input_is_mt_value(code))
965                 return -EINVAL;
966
967         max_slots = (size - sizeof(__u32)) / sizeof(__s32);
968         for (i = 0; i < mt->num_slots && i < max_slots; i++) {
969                 int value = input_mt_get_value(&mt->slots[i], code);
970                 if (put_user(value, &ip[1 + i]))
971                         return -EFAULT;
972         }
973
974         return 0;
975 }
976
977 static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
978                         struct file *file)
979 {
980         client->revoked = true;
981         evdev_ungrab(evdev, client);
982         input_flush_device(&evdev->handle, file);
983         wake_up_interruptible(&evdev->wait);
984
985         return 0;
986 }
987
988 /* must be called with evdev-mutex held */
989 static int evdev_set_mask(struct evdev_client *client,
990                           unsigned int type,
991                           const void __user *codes,
992                           u32 codes_size,
993                           int compat)
994 {
995         unsigned long flags, *mask, *oldmask;
996         size_t cnt;
997         int error;
998
999         /* we allow unknown types and 'codes_size > size' for forward-compat */
1000         cnt = evdev_get_mask_cnt(type);
1001         if (!cnt)
1002                 return 0;
1003
1004         mask = bitmap_zalloc(cnt, GFP_KERNEL);
1005         if (!mask)
1006                 return -ENOMEM;
1007
1008         error = bits_from_user(mask, cnt - 1, codes_size, codes, compat);
1009         if (error < 0) {
1010                 bitmap_free(mask);
1011                 return error;
1012         }
1013
1014         spin_lock_irqsave(&client->buffer_lock, flags);
1015         oldmask = client->evmasks[type];
1016         client->evmasks[type] = mask;
1017         spin_unlock_irqrestore(&client->buffer_lock, flags);
1018
1019         bitmap_free(oldmask);
1020
1021         return 0;
1022 }
1023
1024 /* must be called with evdev-mutex held */
1025 static int evdev_get_mask(struct evdev_client *client,
1026                           unsigned int type,
1027                           void __user *codes,
1028                           u32 codes_size,
1029                           int compat)
1030 {
1031         unsigned long *mask;
1032         size_t cnt, size, xfer_size;
1033         int i;
1034         int error;
1035
1036         /* we allow unknown types and 'codes_size > size' for forward-compat */
1037         cnt = evdev_get_mask_cnt(type);
1038         size = sizeof(unsigned long) * BITS_TO_LONGS(cnt);
1039         xfer_size = min_t(size_t, codes_size, size);
1040
1041         if (cnt > 0) {
1042                 mask = client->evmasks[type];
1043                 if (mask) {
1044                         error = bits_to_user(mask, cnt - 1,
1045                                              xfer_size, codes, compat);
1046                         if (error < 0)
1047                                 return error;
1048                 } else {
1049                         /* fake mask with all bits set */
1050                         for (i = 0; i < xfer_size; i++)
1051                                 if (put_user(0xffU, (u8 __user *)codes + i))
1052                                         return -EFAULT;
1053                 }
1054         }
1055
1056         if (xfer_size < codes_size)
1057                 if (clear_user(codes + xfer_size, codes_size - xfer_size))
1058                         return -EFAULT;
1059
1060         return 0;
1061 }
1062
1063 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
1064                            void __user *p, int compat_mode)
1065 {
1066         struct evdev_client *client = file->private_data;
1067         struct evdev *evdev = client->evdev;
1068         struct input_dev *dev = evdev->handle.dev;
1069         struct input_absinfo abs;
1070         struct input_mask mask;
1071         struct ff_effect effect;
1072         int __user *ip = (int __user *)p;
1073         unsigned int i, t, u, v;
1074         unsigned int size;
1075         int error;
1076
1077         /* First we check for fixed-length commands */
1078         switch (cmd) {
1079
1080         case EVIOCGVERSION:
1081                 return put_user(EV_VERSION, ip);
1082
1083         case EVIOCGID:
1084                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
1085                         return -EFAULT;
1086                 return 0;
1087
1088         case EVIOCGREP:
1089                 if (!test_bit(EV_REP, dev->evbit))
1090                         return -ENOSYS;
1091                 if (put_user(dev->rep[REP_DELAY], ip))
1092                         return -EFAULT;
1093                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
1094                         return -EFAULT;
1095                 return 0;
1096
1097         case EVIOCSREP:
1098                 if (!test_bit(EV_REP, dev->evbit))
1099                         return -ENOSYS;
1100                 if (get_user(u, ip))
1101                         return -EFAULT;
1102                 if (get_user(v, ip + 1))
1103                         return -EFAULT;
1104
1105                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
1106                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
1107
1108                 return 0;
1109
1110         case EVIOCRMFF:
1111                 return input_ff_erase(dev, (int)(unsigned long) p, file);
1112
1113         case EVIOCGEFFECTS:
1114                 i = test_bit(EV_FF, dev->evbit) ?
1115                                 dev->ff->max_effects : 0;
1116                 if (put_user(i, ip))
1117                         return -EFAULT;
1118                 return 0;
1119
1120         case EVIOCGRAB:
1121                 if (p)
1122                         return evdev_grab(evdev, client);
1123                 else
1124                         return evdev_ungrab(evdev, client);
1125
1126         case EVIOCREVOKE:
1127                 if (p)
1128                         return -EINVAL;
1129                 else
1130                         return evdev_revoke(evdev, client, file);
1131
1132         case EVIOCGMASK: {
1133                 void __user *codes_ptr;
1134
1135                 if (copy_from_user(&mask, p, sizeof(mask)))
1136                         return -EFAULT;
1137
1138                 codes_ptr = (void __user *)(unsigned long)mask.codes_ptr;
1139                 return evdev_get_mask(client,
1140                                       mask.type, codes_ptr, mask.codes_size,
1141                                       compat_mode);
1142         }
1143
1144         case EVIOCSMASK: {
1145                 const void __user *codes_ptr;
1146
1147                 if (copy_from_user(&mask, p, sizeof(mask)))
1148                         return -EFAULT;
1149
1150                 codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr;
1151                 return evdev_set_mask(client,
1152                                       mask.type, codes_ptr, mask.codes_size,
1153                                       compat_mode);
1154         }
1155
1156         case EVIOCSCLOCKID:
1157                 if (copy_from_user(&i, p, sizeof(unsigned int)))
1158                         return -EFAULT;
1159
1160                 return evdev_set_clk_type(client, i);
1161
1162         case EVIOCGKEYCODE:
1163                 return evdev_handle_get_keycode(dev, p);
1164
1165         case EVIOCSKEYCODE:
1166                 return evdev_handle_set_keycode(dev, p);
1167
1168         case EVIOCGKEYCODE_V2:
1169                 return evdev_handle_get_keycode_v2(dev, p);
1170
1171         case EVIOCSKEYCODE_V2:
1172                 return evdev_handle_set_keycode_v2(dev, p);
1173         }
1174
1175         size = _IOC_SIZE(cmd);
1176
1177         /* Now check variable-length commands */
1178 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
1179         switch (EVIOC_MASK_SIZE(cmd)) {
1180
1181         case EVIOCGPROP(0):
1182                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
1183                                     size, p, compat_mode);
1184
1185         case EVIOCGMTSLOTS(0):
1186                 return evdev_handle_mt_request(dev, size, ip);
1187
1188         case EVIOCGKEY(0):
1189                 return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
1190                                             KEY_MAX, size, p, compat_mode);
1191
1192         case EVIOCGLED(0):
1193                 return evdev_handle_get_val(client, dev, EV_LED, dev->led,
1194                                             LED_MAX, size, p, compat_mode);
1195
1196         case EVIOCGSND(0):
1197                 return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
1198                                             SND_MAX, size, p, compat_mode);
1199
1200         case EVIOCGSW(0):
1201                 return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
1202                                             SW_MAX, size, p, compat_mode);
1203
1204         case EVIOCGNAME(0):
1205                 return str_to_user(dev->name, size, p);
1206
1207         case EVIOCGPHYS(0):
1208                 return str_to_user(dev->phys, size, p);
1209
1210         case EVIOCGUNIQ(0):
1211                 return str_to_user(dev->uniq, size, p);
1212
1213         case EVIOC_MASK_SIZE(EVIOCSFF):
1214                 if (input_ff_effect_from_user(p, size, &effect))
1215                         return -EFAULT;
1216
1217                 error = input_ff_upload(dev, &effect, file);
1218                 if (error)
1219                         return error;
1220
1221                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
1222                         return -EFAULT;
1223
1224                 return 0;
1225         }
1226
1227         /* Multi-number variable-length handlers */
1228         if (_IOC_TYPE(cmd) != 'E')
1229                 return -EINVAL;
1230
1231         if (_IOC_DIR(cmd) == _IOC_READ) {
1232
1233                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
1234                         return handle_eviocgbit(dev,
1235                                                 _IOC_NR(cmd) & EV_MAX, size,
1236                                                 p, compat_mode);
1237
1238                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1239
1240                         if (!dev->absinfo)
1241                                 return -EINVAL;
1242
1243                         t = _IOC_NR(cmd) & ABS_MAX;
1244                         abs = dev->absinfo[t];
1245
1246                         if (copy_to_user(p, &abs, min_t(size_t,
1247                                         size, sizeof(struct input_absinfo))))
1248                                 return -EFAULT;
1249
1250                         return 0;
1251                 }
1252         }
1253
1254         if (_IOC_DIR(cmd) == _IOC_WRITE) {
1255
1256                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1257
1258                         if (!dev->absinfo)
1259                                 return -EINVAL;
1260
1261                         t = _IOC_NR(cmd) & ABS_MAX;
1262
1263                         if (copy_from_user(&abs, p, min_t(size_t,
1264                                         size, sizeof(struct input_absinfo))))
1265                                 return -EFAULT;
1266
1267                         if (size < sizeof(struct input_absinfo))
1268                                 abs.resolution = 0;
1269
1270                         /* We can't change number of reserved MT slots */
1271                         if (t == ABS_MT_SLOT)
1272                                 return -EINVAL;
1273
1274                         /*
1275                          * Take event lock to ensure that we are not
1276                          * changing device parameters in the middle
1277                          * of event.
1278                          */
1279                         spin_lock_irq(&dev->event_lock);
1280                         dev->absinfo[t] = abs;
1281                         spin_unlock_irq(&dev->event_lock);
1282
1283                         return 0;
1284                 }
1285         }
1286
1287         return -EINVAL;
1288 }
1289
1290 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1291                                 void __user *p, int compat_mode)
1292 {
1293         struct evdev_client *client = file->private_data;
1294         struct evdev *evdev = client->evdev;
1295         int retval;
1296
1297         retval = mutex_lock_interruptible(&evdev->mutex);
1298         if (retval)
1299                 return retval;
1300
1301         if (!evdev->exist || client->revoked) {
1302                 retval = -ENODEV;
1303                 goto out;
1304         }
1305
1306         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1307
1308  out:
1309         mutex_unlock(&evdev->mutex);
1310         return retval;
1311 }
1312
1313 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1314 {
1315         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1316 }
1317
1318 #ifdef CONFIG_COMPAT
1319 static long evdev_ioctl_compat(struct file *file,
1320                                 unsigned int cmd, unsigned long arg)
1321 {
1322         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1323 }
1324 #endif
1325
1326 static const struct file_operations evdev_fops = {
1327         .owner          = THIS_MODULE,
1328         .read           = evdev_read,
1329         .write          = evdev_write,
1330         .poll           = evdev_poll,
1331         .open           = evdev_open,
1332         .release        = evdev_release,
1333         .unlocked_ioctl = evdev_ioctl,
1334 #ifdef CONFIG_COMPAT
1335         .compat_ioctl   = evdev_ioctl_compat,
1336 #endif
1337         .fasync         = evdev_fasync,
1338         .flush          = evdev_flush,
1339         .llseek         = no_llseek,
1340 };
1341
1342 /*
1343  * Mark device non-existent. This disables writes, ioctls and
1344  * prevents new users from opening the device. Already posted
1345  * blocking reads will stay, however new ones will fail.
1346  */
1347 static void evdev_mark_dead(struct evdev *evdev)
1348 {
1349         mutex_lock(&evdev->mutex);
1350         evdev->exist = false;
1351         mutex_unlock(&evdev->mutex);
1352 }
1353
1354 static void evdev_cleanup(struct evdev *evdev)
1355 {
1356         struct input_handle *handle = &evdev->handle;
1357
1358         evdev_mark_dead(evdev);
1359         evdev_hangup(evdev);
1360
1361         /* evdev is marked dead so no one else accesses evdev->open */
1362         if (evdev->open) {
1363                 input_flush_device(handle, NULL);
1364                 input_close_device(handle);
1365         }
1366 }
1367
1368 /*
1369  * Create new evdev device. Note that input core serializes calls
1370  * to connect and disconnect.
1371  */
1372 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1373                          const struct input_device_id *id)
1374 {
1375         struct evdev *evdev;
1376         int minor;
1377         int dev_no;
1378         int error;
1379
1380         minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1381         if (minor < 0) {
1382                 error = minor;
1383                 pr_err("failed to reserve new minor: %d\n", error);
1384                 return error;
1385         }
1386
1387         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1388         if (!evdev) {
1389                 error = -ENOMEM;
1390                 goto err_free_minor;
1391         }
1392
1393         INIT_LIST_HEAD(&evdev->client_list);
1394         spin_lock_init(&evdev->client_lock);
1395         mutex_init(&evdev->mutex);
1396         init_waitqueue_head(&evdev->wait);
1397         evdev->exist = true;
1398
1399         dev_no = minor;
1400         /* Normalize device number if it falls into legacy range */
1401         if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1402                 dev_no -= EVDEV_MINOR_BASE;
1403         dev_set_name(&evdev->dev, "event%d", dev_no);
1404
1405         evdev->handle.dev = input_get_device(dev);
1406         evdev->handle.name = dev_name(&evdev->dev);
1407         evdev->handle.handler = handler;
1408         evdev->handle.private = evdev;
1409
1410         evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1411         evdev->dev.class = &input_class;
1412         evdev->dev.parent = &dev->dev;
1413         evdev->dev.release = evdev_free;
1414         device_initialize(&evdev->dev);
1415
1416         error = input_register_handle(&evdev->handle);
1417         if (error)
1418                 goto err_free_evdev;
1419
1420         cdev_init(&evdev->cdev, &evdev_fops);
1421
1422         error = cdev_device_add(&evdev->cdev, &evdev->dev);
1423         if (error)
1424                 goto err_cleanup_evdev;
1425
1426         return 0;
1427
1428  err_cleanup_evdev:
1429         evdev_cleanup(evdev);
1430         input_unregister_handle(&evdev->handle);
1431  err_free_evdev:
1432         put_device(&evdev->dev);
1433  err_free_minor:
1434         input_free_minor(minor);
1435         return error;
1436 }
1437
1438 static void evdev_disconnect(struct input_handle *handle)
1439 {
1440         struct evdev *evdev = handle->private;
1441
1442         cdev_device_del(&evdev->cdev, &evdev->dev);
1443         evdev_cleanup(evdev);
1444         input_free_minor(MINOR(evdev->dev.devt));
1445         input_unregister_handle(handle);
1446         put_device(&evdev->dev);
1447 }
1448
1449 static const struct input_device_id evdev_ids[] = {
1450         { .driver_info = 1 },   /* Matches all devices */
1451         { },                    /* Terminating zero entry */
1452 };
1453
1454 MODULE_DEVICE_TABLE(input, evdev_ids);
1455
1456 static struct input_handler evdev_handler = {
1457         .event          = evdev_event,
1458         .events         = evdev_events,
1459         .connect        = evdev_connect,
1460         .disconnect     = evdev_disconnect,
1461         .legacy_minors  = true,
1462         .minor          = EVDEV_MINOR_BASE,
1463         .name           = "evdev",
1464         .id_table       = evdev_ids,
1465 };
1466
1467 static int __init evdev_init(void)
1468 {
1469         return input_register_handler(&evdev_handler);
1470 }
1471
1472 static void __exit evdev_exit(void)
1473 {
1474         input_unregister_handler(&evdev_handler);
1475 }
1476
1477 module_init(evdev_init);
1478 module_exit(evdev_exit);
1479
1480 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1481 MODULE_DESCRIPTION("Input driver event char devices");
1482 MODULE_LICENSE("GPL");