f48369d6f3a0f36ef1ab412ac95a2b2b51d55b3d
[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         unsigned int size = sizeof(struct evdev_client) +
507                                         bufsize * sizeof(struct input_event);
508         struct evdev_client *client;
509         int error;
510
511         client = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
512         if (!client)
513                 client = vzalloc(size);
514         if (!client)
515                 return -ENOMEM;
516
517         client->bufsize = bufsize;
518         spin_lock_init(&client->buffer_lock);
519         client->evdev = evdev;
520         evdev_attach_client(evdev, client);
521
522         error = evdev_open_device(evdev);
523         if (error)
524                 goto err_free_client;
525
526         file->private_data = client;
527         nonseekable_open(inode, file);
528
529         return 0;
530
531  err_free_client:
532         evdev_detach_client(evdev, client);
533         kvfree(client);
534         return error;
535 }
536
537 static ssize_t evdev_write(struct file *file, const char __user *buffer,
538                            size_t count, loff_t *ppos)
539 {
540         struct evdev_client *client = file->private_data;
541         struct evdev *evdev = client->evdev;
542         struct input_event event;
543         int retval = 0;
544
545         if (count != 0 && count < input_event_size())
546                 return -EINVAL;
547
548         retval = mutex_lock_interruptible(&evdev->mutex);
549         if (retval)
550                 return retval;
551
552         if (!evdev->exist || client->revoked) {
553                 retval = -ENODEV;
554                 goto out;
555         }
556
557         while (retval + input_event_size() <= count) {
558
559                 if (input_event_from_user(buffer + retval, &event)) {
560                         retval = -EFAULT;
561                         goto out;
562                 }
563                 retval += input_event_size();
564
565                 input_inject_event(&evdev->handle,
566                                    event.type, event.code, event.value);
567                 cond_resched();
568         }
569
570  out:
571         mutex_unlock(&evdev->mutex);
572         return retval;
573 }
574
575 static int evdev_fetch_next_event(struct evdev_client *client,
576                                   struct input_event *event)
577 {
578         int have_event;
579
580         spin_lock_irq(&client->buffer_lock);
581
582         have_event = client->packet_head != client->tail;
583         if (have_event) {
584                 *event = client->buffer[client->tail++];
585                 client->tail &= client->bufsize - 1;
586         }
587
588         spin_unlock_irq(&client->buffer_lock);
589
590         return have_event;
591 }
592
593 static ssize_t evdev_read(struct file *file, char __user *buffer,
594                           size_t count, loff_t *ppos)
595 {
596         struct evdev_client *client = file->private_data;
597         struct evdev *evdev = client->evdev;
598         struct input_event event;
599         size_t read = 0;
600         int error;
601
602         if (count != 0 && count < input_event_size())
603                 return -EINVAL;
604
605         for (;;) {
606                 if (!evdev->exist || client->revoked)
607                         return -ENODEV;
608
609                 if (client->packet_head == client->tail &&
610                     (file->f_flags & O_NONBLOCK))
611                         return -EAGAIN;
612
613                 /*
614                  * count == 0 is special - no IO is done but we check
615                  * for error conditions (see above).
616                  */
617                 if (count == 0)
618                         break;
619
620                 while (read + input_event_size() <= count &&
621                        evdev_fetch_next_event(client, &event)) {
622
623                         if (input_event_to_user(buffer + read, &event))
624                                 return -EFAULT;
625
626                         read += input_event_size();
627                 }
628
629                 if (read)
630                         break;
631
632                 if (!(file->f_flags & O_NONBLOCK)) {
633                         error = wait_event_interruptible(evdev->wait,
634                                         client->packet_head != client->tail ||
635                                         !evdev->exist || client->revoked);
636                         if (error)
637                                 return error;
638                 }
639         }
640
641         return read;
642 }
643
644 /* No kernel lock - fine */
645 static __poll_t evdev_poll(struct file *file, poll_table *wait)
646 {
647         struct evdev_client *client = file->private_data;
648         struct evdev *evdev = client->evdev;
649         __poll_t mask;
650
651         poll_wait(file, &evdev->wait, wait);
652
653         if (evdev->exist && !client->revoked)
654                 mask = EPOLLOUT | EPOLLWRNORM;
655         else
656                 mask = EPOLLHUP | EPOLLERR;
657
658         if (client->packet_head != client->tail)
659                 mask |= EPOLLIN | EPOLLRDNORM;
660
661         return mask;
662 }
663
664 #ifdef CONFIG_COMPAT
665
666 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
667 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
668
669 #ifdef __BIG_ENDIAN
670 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
671                         unsigned int maxlen, void __user *p, int compat)
672 {
673         int len, i;
674
675         if (compat) {
676                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
677                 if (len > maxlen)
678                         len = maxlen;
679
680                 for (i = 0; i < len / sizeof(compat_long_t); i++)
681                         if (copy_to_user((compat_long_t __user *) p + i,
682                                          (compat_long_t *) bits +
683                                                 i + 1 - ((i % 2) << 1),
684                                          sizeof(compat_long_t)))
685                                 return -EFAULT;
686         } else {
687                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
688                 if (len > maxlen)
689                         len = maxlen;
690
691                 if (copy_to_user(p, bits, len))
692                         return -EFAULT;
693         }
694
695         return len;
696 }
697
698 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
699                           unsigned int maxlen, const void __user *p, int compat)
700 {
701         int len, i;
702
703         if (compat) {
704                 if (maxlen % sizeof(compat_long_t))
705                         return -EINVAL;
706
707                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
708                 if (len > maxlen)
709                         len = maxlen;
710
711                 for (i = 0; i < len / sizeof(compat_long_t); i++)
712                         if (copy_from_user((compat_long_t *) bits +
713                                                 i + 1 - ((i % 2) << 1),
714                                            (compat_long_t __user *) p + i,
715                                            sizeof(compat_long_t)))
716                                 return -EFAULT;
717                 if (i % 2)
718                         *((compat_long_t *) bits + i - 1) = 0;
719
720         } else {
721                 if (maxlen % sizeof(long))
722                         return -EINVAL;
723
724                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
725                 if (len > maxlen)
726                         len = maxlen;
727
728                 if (copy_from_user(bits, p, len))
729                         return -EFAULT;
730         }
731
732         return len;
733 }
734
735 #else
736
737 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
738                         unsigned int maxlen, void __user *p, int compat)
739 {
740         int len = compat ?
741                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
742                         BITS_TO_LONGS(maxbit) * sizeof(long);
743
744         if (len > maxlen)
745                 len = maxlen;
746
747         return copy_to_user(p, bits, len) ? -EFAULT : len;
748 }
749
750 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
751                           unsigned int maxlen, const void __user *p, int compat)
752 {
753         size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long);
754         int len;
755
756         if (maxlen % chunk_size)
757                 return -EINVAL;
758
759         len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);
760         len *= chunk_size;
761         if (len > maxlen)
762                 len = maxlen;
763
764         return copy_from_user(bits, p, len) ? -EFAULT : len;
765 }
766
767 #endif /* __BIG_ENDIAN */
768
769 #else
770
771 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
772                         unsigned int maxlen, void __user *p, int compat)
773 {
774         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
775
776         if (len > maxlen)
777                 len = maxlen;
778
779         return copy_to_user(p, bits, len) ? -EFAULT : len;
780 }
781
782 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
783                           unsigned int maxlen, const void __user *p, int compat)
784 {
785         int len;
786
787         if (maxlen % sizeof(long))
788                 return -EINVAL;
789
790         len = BITS_TO_LONGS(maxbit) * sizeof(long);
791         if (len > maxlen)
792                 len = maxlen;
793
794         return copy_from_user(bits, p, len) ? -EFAULT : len;
795 }
796
797 #endif /* CONFIG_COMPAT */
798
799 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
800 {
801         int len;
802
803         if (!str)
804                 return -ENOENT;
805
806         len = strlen(str) + 1;
807         if (len > maxlen)
808                 len = maxlen;
809
810         return copy_to_user(p, str, len) ? -EFAULT : len;
811 }
812
813 static int handle_eviocgbit(struct input_dev *dev,
814                             unsigned int type, unsigned int size,
815                             void __user *p, int compat_mode)
816 {
817         unsigned long *bits;
818         int len;
819
820         switch (type) {
821
822         case      0: bits = dev->evbit;  len = EV_MAX;  break;
823         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
824         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
825         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
826         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
827         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
828         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
829         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
830         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
831         default: return -EINVAL;
832         }
833
834         return bits_to_user(bits, len, size, p, compat_mode);
835 }
836
837 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
838 {
839         struct input_keymap_entry ke = {
840                 .len    = sizeof(unsigned int),
841                 .flags  = 0,
842         };
843         int __user *ip = (int __user *)p;
844         int error;
845
846         /* legacy case */
847         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
848                 return -EFAULT;
849
850         error = input_get_keycode(dev, &ke);
851         if (error)
852                 return error;
853
854         if (put_user(ke.keycode, ip + 1))
855                 return -EFAULT;
856
857         return 0;
858 }
859
860 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
861 {
862         struct input_keymap_entry ke;
863         int error;
864
865         if (copy_from_user(&ke, p, sizeof(ke)))
866                 return -EFAULT;
867
868         error = input_get_keycode(dev, &ke);
869         if (error)
870                 return error;
871
872         if (copy_to_user(p, &ke, sizeof(ke)))
873                 return -EFAULT;
874
875         return 0;
876 }
877
878 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
879 {
880         struct input_keymap_entry ke = {
881                 .len    = sizeof(unsigned int),
882                 .flags  = 0,
883         };
884         int __user *ip = (int __user *)p;
885
886         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
887                 return -EFAULT;
888
889         if (get_user(ke.keycode, ip + 1))
890                 return -EFAULT;
891
892         return input_set_keycode(dev, &ke);
893 }
894
895 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
896 {
897         struct input_keymap_entry ke;
898
899         if (copy_from_user(&ke, p, sizeof(ke)))
900                 return -EFAULT;
901
902         if (ke.len > sizeof(ke.scancode))
903                 return -EINVAL;
904
905         return input_set_keycode(dev, &ke);
906 }
907
908 /*
909  * If we transfer state to the user, we should flush all pending events
910  * of the same type from the client's queue. Otherwise, they might end up
911  * with duplicate events, which can screw up client's state tracking.
912  * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
913  * event so user-space will notice missing events.
914  *
915  * LOCKING:
916  * We need to take event_lock before buffer_lock to avoid dead-locks. But we
917  * need the even_lock only to guarantee consistent state. We can safely release
918  * it while flushing the queue. This allows input-core to handle filters while
919  * we flush the queue.
920  */
921 static int evdev_handle_get_val(struct evdev_client *client,
922                                 struct input_dev *dev, unsigned int type,
923                                 unsigned long *bits, unsigned int maxbit,
924                                 unsigned int maxlen, void __user *p,
925                                 int compat)
926 {
927         int ret;
928         unsigned long *mem;
929
930         mem = bitmap_alloc(maxbit, GFP_KERNEL);
931         if (!mem)
932                 return -ENOMEM;
933
934         spin_lock_irq(&dev->event_lock);
935         spin_lock(&client->buffer_lock);
936
937         bitmap_copy(mem, bits, maxbit);
938
939         spin_unlock(&dev->event_lock);
940
941         __evdev_flush_queue(client, type);
942
943         spin_unlock_irq(&client->buffer_lock);
944
945         ret = bits_to_user(mem, maxbit, maxlen, p, compat);
946         if (ret < 0)
947                 evdev_queue_syn_dropped(client);
948
949         bitmap_free(mem);
950
951         return ret;
952 }
953
954 static int evdev_handle_mt_request(struct input_dev *dev,
955                                    unsigned int size,
956                                    int __user *ip)
957 {
958         const struct input_mt *mt = dev->mt;
959         unsigned int code;
960         int max_slots;
961         int i;
962
963         if (get_user(code, &ip[0]))
964                 return -EFAULT;
965         if (!mt || !input_is_mt_value(code))
966                 return -EINVAL;
967
968         max_slots = (size - sizeof(__u32)) / sizeof(__s32);
969         for (i = 0; i < mt->num_slots && i < max_slots; i++) {
970                 int value = input_mt_get_value(&mt->slots[i], code);
971                 if (put_user(value, &ip[1 + i]))
972                         return -EFAULT;
973         }
974
975         return 0;
976 }
977
978 static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
979                         struct file *file)
980 {
981         client->revoked = true;
982         evdev_ungrab(evdev, client);
983         input_flush_device(&evdev->handle, file);
984         wake_up_interruptible(&evdev->wait);
985
986         return 0;
987 }
988
989 /* must be called with evdev-mutex held */
990 static int evdev_set_mask(struct evdev_client *client,
991                           unsigned int type,
992                           const void __user *codes,
993                           u32 codes_size,
994                           int compat)
995 {
996         unsigned long flags, *mask, *oldmask;
997         size_t cnt;
998         int error;
999
1000         /* we allow unknown types and 'codes_size > size' for forward-compat */
1001         cnt = evdev_get_mask_cnt(type);
1002         if (!cnt)
1003                 return 0;
1004
1005         mask = bitmap_zalloc(cnt, GFP_KERNEL);
1006         if (!mask)
1007                 return -ENOMEM;
1008
1009         error = bits_from_user(mask, cnt - 1, codes_size, codes, compat);
1010         if (error < 0) {
1011                 bitmap_free(mask);
1012                 return error;
1013         }
1014
1015         spin_lock_irqsave(&client->buffer_lock, flags);
1016         oldmask = client->evmasks[type];
1017         client->evmasks[type] = mask;
1018         spin_unlock_irqrestore(&client->buffer_lock, flags);
1019
1020         bitmap_free(oldmask);
1021
1022         return 0;
1023 }
1024
1025 /* must be called with evdev-mutex held */
1026 static int evdev_get_mask(struct evdev_client *client,
1027                           unsigned int type,
1028                           void __user *codes,
1029                           u32 codes_size,
1030                           int compat)
1031 {
1032         unsigned long *mask;
1033         size_t cnt, size, xfer_size;
1034         int i;
1035         int error;
1036
1037         /* we allow unknown types and 'codes_size > size' for forward-compat */
1038         cnt = evdev_get_mask_cnt(type);
1039         size = sizeof(unsigned long) * BITS_TO_LONGS(cnt);
1040         xfer_size = min_t(size_t, codes_size, size);
1041
1042         if (cnt > 0) {
1043                 mask = client->evmasks[type];
1044                 if (mask) {
1045                         error = bits_to_user(mask, cnt - 1,
1046                                              xfer_size, codes, compat);
1047                         if (error < 0)
1048                                 return error;
1049                 } else {
1050                         /* fake mask with all bits set */
1051                         for (i = 0; i < xfer_size; i++)
1052                                 if (put_user(0xffU, (u8 __user *)codes + i))
1053                                         return -EFAULT;
1054                 }
1055         }
1056
1057         if (xfer_size < codes_size)
1058                 if (clear_user(codes + xfer_size, codes_size - xfer_size))
1059                         return -EFAULT;
1060
1061         return 0;
1062 }
1063
1064 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
1065                            void __user *p, int compat_mode)
1066 {
1067         struct evdev_client *client = file->private_data;
1068         struct evdev *evdev = client->evdev;
1069         struct input_dev *dev = evdev->handle.dev;
1070         struct input_absinfo abs;
1071         struct input_mask mask;
1072         struct ff_effect effect;
1073         int __user *ip = (int __user *)p;
1074         unsigned int i, t, u, v;
1075         unsigned int size;
1076         int error;
1077
1078         /* First we check for fixed-length commands */
1079         switch (cmd) {
1080
1081         case EVIOCGVERSION:
1082                 return put_user(EV_VERSION, ip);
1083
1084         case EVIOCGID:
1085                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
1086                         return -EFAULT;
1087                 return 0;
1088
1089         case EVIOCGREP:
1090                 if (!test_bit(EV_REP, dev->evbit))
1091                         return -ENOSYS;
1092                 if (put_user(dev->rep[REP_DELAY], ip))
1093                         return -EFAULT;
1094                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
1095                         return -EFAULT;
1096                 return 0;
1097
1098         case EVIOCSREP:
1099                 if (!test_bit(EV_REP, dev->evbit))
1100                         return -ENOSYS;
1101                 if (get_user(u, ip))
1102                         return -EFAULT;
1103                 if (get_user(v, ip + 1))
1104                         return -EFAULT;
1105
1106                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
1107                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
1108
1109                 return 0;
1110
1111         case EVIOCRMFF:
1112                 return input_ff_erase(dev, (int)(unsigned long) p, file);
1113
1114         case EVIOCGEFFECTS:
1115                 i = test_bit(EV_FF, dev->evbit) ?
1116                                 dev->ff->max_effects : 0;
1117                 if (put_user(i, ip))
1118                         return -EFAULT;
1119                 return 0;
1120
1121         case EVIOCGRAB:
1122                 if (p)
1123                         return evdev_grab(evdev, client);
1124                 else
1125                         return evdev_ungrab(evdev, client);
1126
1127         case EVIOCREVOKE:
1128                 if (p)
1129                         return -EINVAL;
1130                 else
1131                         return evdev_revoke(evdev, client, file);
1132
1133         case EVIOCGMASK: {
1134                 void __user *codes_ptr;
1135
1136                 if (copy_from_user(&mask, p, sizeof(mask)))
1137                         return -EFAULT;
1138
1139                 codes_ptr = (void __user *)(unsigned long)mask.codes_ptr;
1140                 return evdev_get_mask(client,
1141                                       mask.type, codes_ptr, mask.codes_size,
1142                                       compat_mode);
1143         }
1144
1145         case EVIOCSMASK: {
1146                 const void __user *codes_ptr;
1147
1148                 if (copy_from_user(&mask, p, sizeof(mask)))
1149                         return -EFAULT;
1150
1151                 codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr;
1152                 return evdev_set_mask(client,
1153                                       mask.type, codes_ptr, mask.codes_size,
1154                                       compat_mode);
1155         }
1156
1157         case EVIOCSCLOCKID:
1158                 if (copy_from_user(&i, p, sizeof(unsigned int)))
1159                         return -EFAULT;
1160
1161                 return evdev_set_clk_type(client, i);
1162
1163         case EVIOCGKEYCODE:
1164                 return evdev_handle_get_keycode(dev, p);
1165
1166         case EVIOCSKEYCODE:
1167                 return evdev_handle_set_keycode(dev, p);
1168
1169         case EVIOCGKEYCODE_V2:
1170                 return evdev_handle_get_keycode_v2(dev, p);
1171
1172         case EVIOCSKEYCODE_V2:
1173                 return evdev_handle_set_keycode_v2(dev, p);
1174         }
1175
1176         size = _IOC_SIZE(cmd);
1177
1178         /* Now check variable-length commands */
1179 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
1180         switch (EVIOC_MASK_SIZE(cmd)) {
1181
1182         case EVIOCGPROP(0):
1183                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
1184                                     size, p, compat_mode);
1185
1186         case EVIOCGMTSLOTS(0):
1187                 return evdev_handle_mt_request(dev, size, ip);
1188
1189         case EVIOCGKEY(0):
1190                 return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
1191                                             KEY_MAX, size, p, compat_mode);
1192
1193         case EVIOCGLED(0):
1194                 return evdev_handle_get_val(client, dev, EV_LED, dev->led,
1195                                             LED_MAX, size, p, compat_mode);
1196
1197         case EVIOCGSND(0):
1198                 return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
1199                                             SND_MAX, size, p, compat_mode);
1200
1201         case EVIOCGSW(0):
1202                 return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
1203                                             SW_MAX, size, p, compat_mode);
1204
1205         case EVIOCGNAME(0):
1206                 return str_to_user(dev->name, size, p);
1207
1208         case EVIOCGPHYS(0):
1209                 return str_to_user(dev->phys, size, p);
1210
1211         case EVIOCGUNIQ(0):
1212                 return str_to_user(dev->uniq, size, p);
1213
1214         case EVIOC_MASK_SIZE(EVIOCSFF):
1215                 if (input_ff_effect_from_user(p, size, &effect))
1216                         return -EFAULT;
1217
1218                 error = input_ff_upload(dev, &effect, file);
1219                 if (error)
1220                         return error;
1221
1222                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
1223                         return -EFAULT;
1224
1225                 return 0;
1226         }
1227
1228         /* Multi-number variable-length handlers */
1229         if (_IOC_TYPE(cmd) != 'E')
1230                 return -EINVAL;
1231
1232         if (_IOC_DIR(cmd) == _IOC_READ) {
1233
1234                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
1235                         return handle_eviocgbit(dev,
1236                                                 _IOC_NR(cmd) & EV_MAX, size,
1237                                                 p, compat_mode);
1238
1239                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1240
1241                         if (!dev->absinfo)
1242                                 return -EINVAL;
1243
1244                         t = _IOC_NR(cmd) & ABS_MAX;
1245                         abs = dev->absinfo[t];
1246
1247                         if (copy_to_user(p, &abs, min_t(size_t,
1248                                         size, sizeof(struct input_absinfo))))
1249                                 return -EFAULT;
1250
1251                         return 0;
1252                 }
1253         }
1254
1255         if (_IOC_DIR(cmd) == _IOC_WRITE) {
1256
1257                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1258
1259                         if (!dev->absinfo)
1260                                 return -EINVAL;
1261
1262                         t = _IOC_NR(cmd) & ABS_MAX;
1263
1264                         if (copy_from_user(&abs, p, min_t(size_t,
1265                                         size, sizeof(struct input_absinfo))))
1266                                 return -EFAULT;
1267
1268                         if (size < sizeof(struct input_absinfo))
1269                                 abs.resolution = 0;
1270
1271                         /* We can't change number of reserved MT slots */
1272                         if (t == ABS_MT_SLOT)
1273                                 return -EINVAL;
1274
1275                         /*
1276                          * Take event lock to ensure that we are not
1277                          * changing device parameters in the middle
1278                          * of event.
1279                          */
1280                         spin_lock_irq(&dev->event_lock);
1281                         dev->absinfo[t] = abs;
1282                         spin_unlock_irq(&dev->event_lock);
1283
1284                         return 0;
1285                 }
1286         }
1287
1288         return -EINVAL;
1289 }
1290
1291 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1292                                 void __user *p, int compat_mode)
1293 {
1294         struct evdev_client *client = file->private_data;
1295         struct evdev *evdev = client->evdev;
1296         int retval;
1297
1298         retval = mutex_lock_interruptible(&evdev->mutex);
1299         if (retval)
1300                 return retval;
1301
1302         if (!evdev->exist || client->revoked) {
1303                 retval = -ENODEV;
1304                 goto out;
1305         }
1306
1307         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1308
1309  out:
1310         mutex_unlock(&evdev->mutex);
1311         return retval;
1312 }
1313
1314 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1315 {
1316         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1317 }
1318
1319 #ifdef CONFIG_COMPAT
1320 static long evdev_ioctl_compat(struct file *file,
1321                                 unsigned int cmd, unsigned long arg)
1322 {
1323         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1324 }
1325 #endif
1326
1327 static const struct file_operations evdev_fops = {
1328         .owner          = THIS_MODULE,
1329         .read           = evdev_read,
1330         .write          = evdev_write,
1331         .poll           = evdev_poll,
1332         .open           = evdev_open,
1333         .release        = evdev_release,
1334         .unlocked_ioctl = evdev_ioctl,
1335 #ifdef CONFIG_COMPAT
1336         .compat_ioctl   = evdev_ioctl_compat,
1337 #endif
1338         .fasync         = evdev_fasync,
1339         .flush          = evdev_flush,
1340         .llseek         = no_llseek,
1341 };
1342
1343 /*
1344  * Mark device non-existent. This disables writes, ioctls and
1345  * prevents new users from opening the device. Already posted
1346  * blocking reads will stay, however new ones will fail.
1347  */
1348 static void evdev_mark_dead(struct evdev *evdev)
1349 {
1350         mutex_lock(&evdev->mutex);
1351         evdev->exist = false;
1352         mutex_unlock(&evdev->mutex);
1353 }
1354
1355 static void evdev_cleanup(struct evdev *evdev)
1356 {
1357         struct input_handle *handle = &evdev->handle;
1358
1359         evdev_mark_dead(evdev);
1360         evdev_hangup(evdev);
1361
1362         /* evdev is marked dead so no one else accesses evdev->open */
1363         if (evdev->open) {
1364                 input_flush_device(handle, NULL);
1365                 input_close_device(handle);
1366         }
1367 }
1368
1369 /*
1370  * Create new evdev device. Note that input core serializes calls
1371  * to connect and disconnect.
1372  */
1373 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1374                          const struct input_device_id *id)
1375 {
1376         struct evdev *evdev;
1377         int minor;
1378         int dev_no;
1379         int error;
1380
1381         minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1382         if (minor < 0) {
1383                 error = minor;
1384                 pr_err("failed to reserve new minor: %d\n", error);
1385                 return error;
1386         }
1387
1388         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1389         if (!evdev) {
1390                 error = -ENOMEM;
1391                 goto err_free_minor;
1392         }
1393
1394         INIT_LIST_HEAD(&evdev->client_list);
1395         spin_lock_init(&evdev->client_lock);
1396         mutex_init(&evdev->mutex);
1397         init_waitqueue_head(&evdev->wait);
1398         evdev->exist = true;
1399
1400         dev_no = minor;
1401         /* Normalize device number if it falls into legacy range */
1402         if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1403                 dev_no -= EVDEV_MINOR_BASE;
1404         dev_set_name(&evdev->dev, "event%d", dev_no);
1405
1406         evdev->handle.dev = input_get_device(dev);
1407         evdev->handle.name = dev_name(&evdev->dev);
1408         evdev->handle.handler = handler;
1409         evdev->handle.private = evdev;
1410
1411         evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1412         evdev->dev.class = &input_class;
1413         evdev->dev.parent = &dev->dev;
1414         evdev->dev.release = evdev_free;
1415         device_initialize(&evdev->dev);
1416
1417         error = input_register_handle(&evdev->handle);
1418         if (error)
1419                 goto err_free_evdev;
1420
1421         cdev_init(&evdev->cdev, &evdev_fops);
1422
1423         error = cdev_device_add(&evdev->cdev, &evdev->dev);
1424         if (error)
1425                 goto err_cleanup_evdev;
1426
1427         return 0;
1428
1429  err_cleanup_evdev:
1430         evdev_cleanup(evdev);
1431         input_unregister_handle(&evdev->handle);
1432  err_free_evdev:
1433         put_device(&evdev->dev);
1434  err_free_minor:
1435         input_free_minor(minor);
1436         return error;
1437 }
1438
1439 static void evdev_disconnect(struct input_handle *handle)
1440 {
1441         struct evdev *evdev = handle->private;
1442
1443         cdev_device_del(&evdev->cdev, &evdev->dev);
1444         evdev_cleanup(evdev);
1445         input_free_minor(MINOR(evdev->dev.devt));
1446         input_unregister_handle(handle);
1447         put_device(&evdev->dev);
1448 }
1449
1450 static const struct input_device_id evdev_ids[] = {
1451         { .driver_info = 1 },   /* Matches all devices */
1452         { },                    /* Terminating zero entry */
1453 };
1454
1455 MODULE_DEVICE_TABLE(input, evdev_ids);
1456
1457 static struct input_handler evdev_handler = {
1458         .event          = evdev_event,
1459         .events         = evdev_events,
1460         .connect        = evdev_connect,
1461         .disconnect     = evdev_disconnect,
1462         .legacy_minors  = true,
1463         .minor          = EVDEV_MINOR_BASE,
1464         .name           = "evdev",
1465         .id_table       = evdev_ids,
1466 };
1467
1468 static int __init evdev_init(void)
1469 {
1470         return input_register_handler(&evdev_handler);
1471 }
1472
1473 static void __exit evdev_exit(void)
1474 {
1475         input_unregister_handler(&evdev_handler);
1476 }
1477
1478 module_init(evdev_init);
1479 module_exit(evdev_exit);
1480
1481 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1482 MODULE_DESCRIPTION("Input driver event char devices");
1483 MODULE_LICENSE("GPL");