projects/linux·blob v3.4 · refs

1057 lines · 23.6 KiB

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/module.h>
22#include <linux/init.h>
23#include <linux/input/mt.h>
24#include <linux/major.h>
25#include <linux/device.h>
26#include "input-compat.h"
27
28struct evdev {
29 int open;
30 int minor;
31 struct input_handle handle;
32 wait_queue_head_t wait;
33 struct evdev_client __rcu *grab;
34 struct list_head client_list;
35 spinlock_t client_lock; /* protects client_list */
36 struct mutex mutex;
37 struct device dev;
38 bool exist;
39};
40
41struct evdev_client {
42 unsigned int head;
43 unsigned int tail;
44 unsigned int packet_head; /* [future] position of the first element of next packet */
45 spinlock_t buffer_lock; /* protects access to buffer, head and tail */
46 struct fasync_struct *fasync;
47 struct evdev *evdev;
48 struct list_head node;
49 int clkid;
50 unsigned int bufsize;
51 struct input_event buffer[];
52};
53
54static struct evdev *evdev_table[EVDEV_MINORS];
55static DEFINE_MUTEX(evdev_table_mutex);
56
57static void evdev_pass_event(struct evdev_client *client,
58 struct input_event *event,
59 ktime_t mono, ktime_t real)
60{
61 event->time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ?
62 mono : real);
63
64 /* Interrupts are disabled, just acquire the lock. */
65 spin_lock(&client->buffer_lock);
66
67 client->buffer[client->head++] = *event;
68 client->head &= client->bufsize - 1;
69
70 if (unlikely(client->head == client->tail)) {
71 /*
72 * This effectively "drops" all unconsumed events, leaving
73 * EV_SYN/SYN_DROPPED plus the newest event in the queue.
74 */
75 client->tail = (client->head - 2) & (client->bufsize - 1);
76
77 client->buffer[client->tail].time = event->time;
78 client->buffer[client->tail].type = EV_SYN;
79 client->buffer[client->tail].code = SYN_DROPPED;
80 client->buffer[client->tail].value = 0;
81
82 client->packet_head = client->tail;
83 }
84
85 if (event->type == EV_SYN && event->code == SYN_REPORT) {
86 client->packet_head = client->head;
87 kill_fasync(&client->fasync, SIGIO, POLL_IN);
88 }
89
90 spin_unlock(&client->buffer_lock);
91}
92
93/*
94 * Pass incoming event to all connected clients.
95 */
96static void evdev_event(struct input_handle *handle,
97 unsigned int type, unsigned int code, int value)
98{
99 struct evdev *evdev = handle->private;
100 struct evdev_client *client;
101 struct input_event event;
102 ktime_t time_mono, time_real;
103
104 time_mono = ktime_get();
105 time_real = ktime_sub(time_mono, ktime_get_monotonic_offset());
106
107 event.type = type;
108 event.code = code;
109 event.value = value;
110
111 rcu_read_lock();
112
113 client = rcu_dereference(evdev->grab);
114
115 if (client)
116 evdev_pass_event(client, &event, time_mono, time_real);
117 else
118 list_for_each_entry_rcu(client, &evdev->client_list, node)
119 evdev_pass_event(client, &event, time_mono, time_real);
120
121 rcu_read_unlock();
122
123 if (type == EV_SYN && code == SYN_REPORT)
124 wake_up_interruptible(&evdev->wait);
125}
126
127static int evdev_fasync(int fd, struct file *file, int on)
128{
129 struct evdev_client *client = file->private_data;
130
131 return fasync_helper(fd, file, on, &client->fasync);
132}
133
134static int evdev_flush(struct file *file, fl_owner_t id)
135{
136 struct evdev_client *client = file->private_data;
137 struct evdev *evdev = client->evdev;
138 int retval;
139
140 retval = mutex_lock_interruptible(&evdev->mutex);
141 if (retval)
142 return retval;
143
144 if (!evdev->exist)
145 retval = -ENODEV;
146 else
147 retval = input_flush_device(&evdev->handle, file);
148
149 mutex_unlock(&evdev->mutex);
150 return retval;
151}
152
153static void evdev_free(struct device *dev)
154{
155 struct evdev *evdev = container_of(dev, struct evdev, dev);
156
157 input_put_device(evdev->handle.dev);
158 kfree(evdev);
159}
160
161/*
162 * Grabs an event device (along with underlying input device).
163 * This function is called with evdev->mutex taken.
164 */
165static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
166{
167 int error;
168
169 if (evdev->grab)
170 return -EBUSY;
171
172 error = input_grab_device(&evdev->handle);
173 if (error)
174 return error;
175
176 rcu_assign_pointer(evdev->grab, client);
177
178 return 0;
179}
180
181static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
182{
183 if (evdev->grab != client)
184 return -EINVAL;
185
186 rcu_assign_pointer(evdev->grab, NULL);
187 synchronize_rcu();
188 input_release_device(&evdev->handle);
189
190 return 0;
191}
192
193static void evdev_attach_client(struct evdev *evdev,
194 struct evdev_client *client)
195{
196 spin_lock(&evdev->client_lock);
197 list_add_tail_rcu(&client->node, &evdev->client_list);
198 spin_unlock(&evdev->client_lock);
199}
200
201static void evdev_detach_client(struct evdev *evdev,
202 struct evdev_client *client)
203{
204 spin_lock(&evdev->client_lock);
205 list_del_rcu(&client->node);
206 spin_unlock(&evdev->client_lock);
207 synchronize_rcu();
208}
209
210static int evdev_open_device(struct evdev *evdev)
211{
212 int retval;
213
214 retval = mutex_lock_interruptible(&evdev->mutex);
215 if (retval)
216 return retval;
217
218 if (!evdev->exist)
219 retval = -ENODEV;
220 else if (!evdev->open++) {
221 retval = input_open_device(&evdev->handle);
222 if (retval)
223 evdev->open--;
224 }
225
226 mutex_unlock(&evdev->mutex);
227 return retval;
228}
229
230static void evdev_close_device(struct evdev *evdev)
231{
232 mutex_lock(&evdev->mutex);
233
234 if (evdev->exist && !--evdev->open)
235 input_close_device(&evdev->handle);
236
237 mutex_unlock(&evdev->mutex);
238}
239
240/*
241 * Wake up users waiting for IO so they can disconnect from
242 * dead device.
243 */
244static void evdev_hangup(struct evdev *evdev)
245{
246 struct evdev_client *client;
247
248 spin_lock(&evdev->client_lock);
249 list_for_each_entry(client, &evdev->client_list, node)
250 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
251 spin_unlock(&evdev->client_lock);
252
253 wake_up_interruptible(&evdev->wait);
254}
255
256static int evdev_release(struct inode *inode, struct file *file)
257{
258 struct evdev_client *client = file->private_data;
259 struct evdev *evdev = client->evdev;
260
261 mutex_lock(&evdev->mutex);
262 if (evdev->grab == client)
263 evdev_ungrab(evdev, client);
264 mutex_unlock(&evdev->mutex);
265
266 evdev_detach_client(evdev, client);
267 kfree(client);
268
269 evdev_close_device(evdev);
270 put_device(&evdev->dev);
271
272 return 0;
273}
274
275static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
276{
277 unsigned int n_events =
278 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
279 EVDEV_MIN_BUFFER_SIZE);
280
281 return roundup_pow_of_two(n_events);
282}
283
284static int evdev_open(struct inode *inode, struct file *file)
285{
286 struct evdev *evdev;
287 struct evdev_client *client;
288 int i = iminor(inode) - EVDEV_MINOR_BASE;
289 unsigned int bufsize;
290 int error;
291
292 if (i >= EVDEV_MINORS)
293 return -ENODEV;
294
295 error = mutex_lock_interruptible(&evdev_table_mutex);
296 if (error)
297 return error;
298 evdev = evdev_table[i];
299 if (evdev)
300 get_device(&evdev->dev);
301 mutex_unlock(&evdev_table_mutex);
302
303 if (!evdev)
304 return -ENODEV;
305
306 bufsize = evdev_compute_buffer_size(evdev->handle.dev);
307
308 client = kzalloc(sizeof(struct evdev_client) +
309 bufsize * sizeof(struct input_event),
310 GFP_KERNEL);
311 if (!client) {
312 error = -ENOMEM;
313 goto err_put_evdev;
314 }
315
316 client->bufsize = bufsize;
317 spin_lock_init(&client->buffer_lock);
318 client->evdev = evdev;
319 evdev_attach_client(evdev, client);
320
321 error = evdev_open_device(evdev);
322 if (error)
323 goto err_free_client;
324
325 file->private_data = client;
326 nonseekable_open(inode, file);
327
328 return 0;
329
330 err_free_client:
331 evdev_detach_client(evdev, client);
332 kfree(client);
333 err_put_evdev:
334 put_device(&evdev->dev);
335 return error;
336}
337
338static ssize_t evdev_write(struct file *file, const char __user *buffer,
339 size_t count, loff_t *ppos)
340{
341 struct evdev_client *client = file->private_data;
342 struct evdev *evdev = client->evdev;
343 struct input_event event;
344 int retval = 0;
345
346 if (count < input_event_size())
347 return -EINVAL;
348
349 retval = mutex_lock_interruptible(&evdev->mutex);
350 if (retval)
351 return retval;
352
353 if (!evdev->exist) {
354 retval = -ENODEV;
355 goto out;
356 }
357
358 do {
359 if (input_event_from_user(buffer + retval, &event)) {
360 retval = -EFAULT;
361 goto out;
362 }
363 retval += input_event_size();
364
365 input_inject_event(&evdev->handle,
366 event.type, event.code, event.value);
367 } while (retval + input_event_size() <= count);
368
369 out:
370 mutex_unlock(&evdev->mutex);
371 return retval;
372}
373
374static int evdev_fetch_next_event(struct evdev_client *client,
375 struct input_event *event)
376{
377 int have_event;
378
379 spin_lock_irq(&client->buffer_lock);
380
381 have_event = client->packet_head != client->tail;
382 if (have_event) {
383 *event = client->buffer[client->tail++];
384 client->tail &= client->bufsize - 1;
385 }
386
387 spin_unlock_irq(&client->buffer_lock);
388
389 return have_event;
390}
391
392static ssize_t evdev_read(struct file *file, char __user *buffer,
393 size_t count, loff_t *ppos)
394{
395 struct evdev_client *client = file->private_data;
396 struct evdev *evdev = client->evdev;
397 struct input_event event;
398 int retval = 0;
399
400 if (count < input_event_size())
401 return -EINVAL;
402
403 if (!(file->f_flags & O_NONBLOCK)) {
404 retval = wait_event_interruptible(evdev->wait,
405 client->packet_head != client->tail ||
406 !evdev->exist);
407 if (retval)
408 return retval;
409 }
410
411 if (!evdev->exist)
412 return -ENODEV;
413
414 while (retval + input_event_size() <= count &&
415 evdev_fetch_next_event(client, &event)) {
416
417 if (input_event_to_user(buffer + retval, &event))
418 return -EFAULT;
419
420 retval += input_event_size();
421 }
422
423 if (retval == 0 && (file->f_flags & O_NONBLOCK))
424 return -EAGAIN;
425
426 return retval;
427}
428
429/* No kernel lock - fine */
430static unsigned int evdev_poll(struct file *file, poll_table *wait)
431{
432 struct evdev_client *client = file->private_data;
433 struct evdev *evdev = client->evdev;
434 unsigned int mask;
435
436 poll_wait(file, &evdev->wait, wait);
437
438 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
439 if (client->packet_head != client->tail)
440 mask |= POLLIN | POLLRDNORM;
441
442 return mask;
443}
444
445#ifdef CONFIG_COMPAT
446
447#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
448#define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
449
450#ifdef __BIG_ENDIAN
451static int bits_to_user(unsigned long *bits, unsigned int maxbit,
452 unsigned int maxlen, void __user *p, int compat)
453{
454 int len, i;
455
456 if (compat) {
457 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
458 if (len > maxlen)
459 len = maxlen;
460
461 for (i = 0; i < len / sizeof(compat_long_t); i++)
462 if (copy_to_user((compat_long_t __user *) p + i,
463 (compat_long_t *) bits +
464 i + 1 - ((i % 2) << 1),
465 sizeof(compat_long_t)))
466 return -EFAULT;
467 } else {
468 len = BITS_TO_LONGS(maxbit) * sizeof(long);
469 if (len > maxlen)
470 len = maxlen;
471
472 if (copy_to_user(p, bits, len))
473 return -EFAULT;
474 }
475
476 return len;
477}
478#else
479static int bits_to_user(unsigned long *bits, unsigned int maxbit,
480 unsigned int maxlen, void __user *p, int compat)
481{
482 int len = compat ?
483 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
484 BITS_TO_LONGS(maxbit) * sizeof(long);
485
486 if (len > maxlen)
487 len = maxlen;
488
489 return copy_to_user(p, bits, len) ? -EFAULT : len;
490}
491#endif /* __BIG_ENDIAN */
492
493#else
494
495static int bits_to_user(unsigned long *bits, unsigned int maxbit,
496 unsigned int maxlen, void __user *p, int compat)
497{
498 int len = BITS_TO_LONGS(maxbit) * sizeof(long);
499
500 if (len > maxlen)
501 len = maxlen;
502
503 return copy_to_user(p, bits, len) ? -EFAULT : len;
504}
505
506#endif /* CONFIG_COMPAT */
507
508static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
509{
510 int len;
511
512 if (!str)
513 return -ENOENT;
514
515 len = strlen(str) + 1;
516 if (len > maxlen)
517 len = maxlen;
518
519 return copy_to_user(p, str, len) ? -EFAULT : len;
520}
521
522#define OLD_KEY_MAX 0x1ff
523static int handle_eviocgbit(struct input_dev *dev,
524 unsigned int type, unsigned int size,
525 void __user *p, int compat_mode)
526{
527 static unsigned long keymax_warn_time;
528 unsigned long *bits;
529 int len;
530
531 switch (type) {
532
533 case 0: bits = dev->evbit; len = EV_MAX; break;
534 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
535 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
536 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
537 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
538 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
539 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
540 case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
541 case EV_SW: bits = dev->swbit; len = SW_MAX; break;
542 default: return -EINVAL;
543 }
544
545 /*
546 * Work around bugs in userspace programs that like to do
547 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
548 * should be in bytes, not in bits.
549 */
550 if (type == EV_KEY && size == OLD_KEY_MAX) {
551 len = OLD_KEY_MAX;
552 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
553 pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
554 "limiting output to %zu bytes. See "
555 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
556 OLD_KEY_MAX,
557 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
558 }
559
560 return bits_to_user(bits, len, size, p, compat_mode);
561}
562#undef OLD_KEY_MAX
563
564static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
565{
566 struct input_keymap_entry ke = {
567 .len = sizeof(unsigned int),
568 .flags = 0,
569 };
570 int __user *ip = (int __user *)p;
571 int error;
572
573 /* legacy case */
574 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
575 return -EFAULT;
576
577 error = input_get_keycode(dev, &ke);
578 if (error)
579 return error;
580
581 if (put_user(ke.keycode, ip + 1))
582 return -EFAULT;
583
584 return 0;
585}
586
587static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
588{
589 struct input_keymap_entry ke;
590 int error;
591
592 if (copy_from_user(&ke, p, sizeof(ke)))
593 return -EFAULT;
594
595 error = input_get_keycode(dev, &ke);
596 if (error)
597 return error;
598
599 if (copy_to_user(p, &ke, sizeof(ke)))
600 return -EFAULT;
601
602 return 0;
603}
604
605static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
606{
607 struct input_keymap_entry ke = {
608 .len = sizeof(unsigned int),
609 .flags = 0,
610 };
611 int __user *ip = (int __user *)p;
612
613 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
614 return -EFAULT;
615
616 if (get_user(ke.keycode, ip + 1))
617 return -EFAULT;
618
619 return input_set_keycode(dev, &ke);
620}
621
622static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
623{
624 struct input_keymap_entry ke;
625
626 if (copy_from_user(&ke, p, sizeof(ke)))
627 return -EFAULT;
628
629 if (ke.len > sizeof(ke.scancode))
630 return -EINVAL;
631
632 return input_set_keycode(dev, &ke);
633}
634
635static int evdev_handle_mt_request(struct input_dev *dev,
636 unsigned int size,
637 int __user *ip)
638{
639 const struct input_mt_slot *mt = dev->mt;
640 unsigned int code;
641 int max_slots;
642 int i;
643
644 if (get_user(code, &ip[0]))
645 return -EFAULT;
646 if (!input_is_mt_value(code))
647 return -EINVAL;
648
649 max_slots = (size - sizeof(__u32)) / sizeof(__s32);
650 for (i = 0; i < dev->mtsize && i < max_slots; i++)
651 if (put_user(input_mt_get_value(&mt[i], code), &ip[1 + i]))
652 return -EFAULT;
653
654 return 0;
655}
656
657static long evdev_do_ioctl(struct file *file, unsigned int cmd,
658 void __user *p, int compat_mode)
659{
660 struct evdev_client *client = file->private_data;
661 struct evdev *evdev = client->evdev;
662 struct input_dev *dev = evdev->handle.dev;
663 struct input_absinfo abs;
664 struct ff_effect effect;
665 int __user *ip = (int __user *)p;
666 unsigned int i, t, u, v;
667 unsigned int size;
668 int error;
669
670 /* First we check for fixed-length commands */
671 switch (cmd) {
672
673 case EVIOCGVERSION:
674 return put_user(EV_VERSION, ip);
675
676 case EVIOCGID:
677 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
678 return -EFAULT;
679 return 0;
680
681 case EVIOCGREP:
682 if (!test_bit(EV_REP, dev->evbit))
683 return -ENOSYS;
684 if (put_user(dev->rep[REP_DELAY], ip))
685 return -EFAULT;
686 if (put_user(dev->rep[REP_PERIOD], ip + 1))
687 return -EFAULT;
688 return 0;
689
690 case EVIOCSREP:
691 if (!test_bit(EV_REP, dev->evbit))
692 return -ENOSYS;
693 if (get_user(u, ip))
694 return -EFAULT;
695 if (get_user(v, ip + 1))
696 return -EFAULT;
697
698 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
699 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
700
701 return 0;
702
703 case EVIOCRMFF:
704 return input_ff_erase(dev, (int)(unsigned long) p, file);
705
706 case EVIOCGEFFECTS:
707 i = test_bit(EV_FF, dev->evbit) ?
708 dev->ff->max_effects : 0;
709 if (put_user(i, ip))
710 return -EFAULT;
711 return 0;
712
713 case EVIOCGRAB:
714 if (p)
715 return evdev_grab(evdev, client);
716 else
717 return evdev_ungrab(evdev, client);
718
719 case EVIOCSCLOCKID:
720 if (copy_from_user(&i, p, sizeof(unsigned int)))
721 return -EFAULT;
722 if (i != CLOCK_MONOTONIC && i != CLOCK_REALTIME)
723 return -EINVAL;
724 client->clkid = i;
725 return 0;
726
727 case EVIOCGKEYCODE:
728 return evdev_handle_get_keycode(dev, p);
729
730 case EVIOCSKEYCODE:
731 return evdev_handle_set_keycode(dev, p);
732
733 case EVIOCGKEYCODE_V2:
734 return evdev_handle_get_keycode_v2(dev, p);
735
736 case EVIOCSKEYCODE_V2:
737 return evdev_handle_set_keycode_v2(dev, p);
738 }
739
740 size = _IOC_SIZE(cmd);
741
742 /* Now check variable-length commands */
743#define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
744 switch (EVIOC_MASK_SIZE(cmd)) {
745
746 case EVIOCGPROP(0):
747 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
748 size, p, compat_mode);
749
750 case EVIOCGMTSLOTS(0):
751 return evdev_handle_mt_request(dev, size, ip);
752
753 case EVIOCGKEY(0):
754 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
755
756 case EVIOCGLED(0):
757 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
758
759 case EVIOCGSND(0):
760 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
761
762 case EVIOCGSW(0):
763 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
764
765 case EVIOCGNAME(0):
766 return str_to_user(dev->name, size, p);
767
768 case EVIOCGPHYS(0):
769 return str_to_user(dev->phys, size, p);
770
771 case EVIOCGUNIQ(0):
772 return str_to_user(dev->uniq, size, p);
773
774 case EVIOC_MASK_SIZE(EVIOCSFF):
775 if (input_ff_effect_from_user(p, size, &effect))
776 return -EFAULT;
777
778 error = input_ff_upload(dev, &effect, file);
779
780 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
781 return -EFAULT;
782
783 return error;
784 }
785
786 /* Multi-number variable-length handlers */
787 if (_IOC_TYPE(cmd) != 'E')
788 return -EINVAL;
789
790 if (_IOC_DIR(cmd) == _IOC_READ) {
791
792 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
793 return handle_eviocgbit(dev,
794 _IOC_NR(cmd) & EV_MAX, size,
795 p, compat_mode);
796
797 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
798
799 if (!dev->absinfo)
800 return -EINVAL;
801
802 t = _IOC_NR(cmd) & ABS_MAX;
803 abs = dev->absinfo[t];
804
805 if (copy_to_user(p, &abs, min_t(size_t,
806 size, sizeof(struct input_absinfo))))
807 return -EFAULT;
808
809 return 0;
810 }
811 }
812
813 if (_IOC_DIR(cmd) == _IOC_WRITE) {
814
815 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
816
817 if (!dev->absinfo)
818 return -EINVAL;
819
820 t = _IOC_NR(cmd) & ABS_MAX;
821
822 if (copy_from_user(&abs, p, min_t(size_t,
823 size, sizeof(struct input_absinfo))))
824 return -EFAULT;
825
826 if (size < sizeof(struct input_absinfo))
827 abs.resolution = 0;
828
829 /* We can't change number of reserved MT slots */
830 if (t == ABS_MT_SLOT)
831 return -EINVAL;
832
833 /*
834 * Take event lock to ensure that we are not
835 * changing device parameters in the middle
836 * of event.
837 */
838 spin_lock_irq(&dev->event_lock);
839 dev->absinfo[t] = abs;
840 spin_unlock_irq(&dev->event_lock);
841
842 return 0;
843 }
844 }
845
846 return -EINVAL;
847}
848
849static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
850 void __user *p, int compat_mode)
851{
852 struct evdev_client *client = file->private_data;
853 struct evdev *evdev = client->evdev;
854 int retval;
855
856 retval = mutex_lock_interruptible(&evdev->mutex);
857 if (retval)
858 return retval;
859
860 if (!evdev->exist) {
861 retval = -ENODEV;
862 goto out;
863 }
864
865 retval = evdev_do_ioctl(file, cmd, p, compat_mode);
866
867 out:
868 mutex_unlock(&evdev->mutex);
869 return retval;
870}
871
872static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
873{
874 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
875}
876
877#ifdef CONFIG_COMPAT
878static long evdev_ioctl_compat(struct file *file,
879 unsigned int cmd, unsigned long arg)
880{
881 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
882}
883#endif
884
885static const struct file_operations evdev_fops = {
886 .owner = THIS_MODULE,
887 .read = evdev_read,
888 .write = evdev_write,
889 .poll = evdev_poll,
890 .open = evdev_open,
891 .release = evdev_release,
892 .unlocked_ioctl = evdev_ioctl,
893#ifdef CONFIG_COMPAT
894 .compat_ioctl = evdev_ioctl_compat,
895#endif
896 .fasync = evdev_fasync,
897 .flush = evdev_flush,
898 .llseek = no_llseek,
899};
900
901static int evdev_install_chrdev(struct evdev *evdev)
902{
903 /*
904 * No need to do any locking here as calls to connect and
905 * disconnect are serialized by the input core
906 */
907 evdev_table[evdev->minor] = evdev;
908 return 0;
909}
910
911static void evdev_remove_chrdev(struct evdev *evdev)
912{
913 /*
914 * Lock evdev table to prevent race with evdev_open()
915 */
916 mutex_lock(&evdev_table_mutex);
917 evdev_table[evdev->minor] = NULL;
918 mutex_unlock(&evdev_table_mutex);
919}
920
921/*
922 * Mark device non-existent. This disables writes, ioctls and
923 * prevents new users from opening the device. Already posted
924 * blocking reads will stay, however new ones will fail.
925 */
926static void evdev_mark_dead(struct evdev *evdev)
927{
928 mutex_lock(&evdev->mutex);
929 evdev->exist = false;
930 mutex_unlock(&evdev->mutex);
931}
932
933static void evdev_cleanup(struct evdev *evdev)
934{
935 struct input_handle *handle = &evdev->handle;
936
937 evdev_mark_dead(evdev);
938 evdev_hangup(evdev);
939 evdev_remove_chrdev(evdev);
940
941 /* evdev is marked dead so no one else accesses evdev->open */
942 if (evdev->open) {
943 input_flush_device(handle, NULL);
944 input_close_device(handle);
945 }
946}
947
948/*
949 * Create new evdev device. Note that input core serializes calls
950 * to connect and disconnect so we don't need to lock evdev_table here.
951 */
952static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
953 const struct input_device_id *id)
954{
955 struct evdev *evdev;
956 int minor;
957 int error;
958
959 for (minor = 0; minor < EVDEV_MINORS; minor++)
960 if (!evdev_table[minor])
961 break;
962
963 if (minor == EVDEV_MINORS) {
964 pr_err("no more free evdev devices\n");
965 return -ENFILE;
966 }
967
968 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
969 if (!evdev)
970 return -ENOMEM;
971
972 INIT_LIST_HEAD(&evdev->client_list);
973 spin_lock_init(&evdev->client_lock);
974 mutex_init(&evdev->mutex);
975 init_waitqueue_head(&evdev->wait);
976
977 dev_set_name(&evdev->dev, "event%d", minor);
978 evdev->exist = true;
979 evdev->minor = minor;
980
981 evdev->handle.dev = input_get_device(dev);
982 evdev->handle.name = dev_name(&evdev->dev);
983 evdev->handle.handler = handler;
984 evdev->handle.private = evdev;
985
986 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
987 evdev->dev.class = &input_class;
988 evdev->dev.parent = &dev->dev;
989 evdev->dev.release = evdev_free;
990 device_initialize(&evdev->dev);
991
992 error = input_register_handle(&evdev->handle);
993 if (error)
994 goto err_free_evdev;
995
996 error = evdev_install_chrdev(evdev);
997 if (error)
998 goto err_unregister_handle;
999
1000 error = device_add(&evdev->dev);
1001 if (error)
1002 goto err_cleanup_evdev;
1003
1004 return 0;
1005
1006 err_cleanup_evdev:
1007 evdev_cleanup(evdev);
1008 err_unregister_handle:
1009 input_unregister_handle(&evdev->handle);
1010 err_free_evdev:
1011 put_device(&evdev->dev);
1012 return error;
1013}
1014
1015static void evdev_disconnect(struct input_handle *handle)
1016{
1017 struct evdev *evdev = handle->private;
1018
1019 device_del(&evdev->dev);
1020 evdev_cleanup(evdev);
1021 input_unregister_handle(handle);
1022 put_device(&evdev->dev);
1023}
1024
1025static const struct input_device_id evdev_ids[] = {
1026 { .driver_info = 1 }, /* Matches all devices */
1027 { }, /* Terminating zero entry */
1028};
1029
1030MODULE_DEVICE_TABLE(input, evdev_ids);
1031
1032static struct input_handler evdev_handler = {
1033 .event = evdev_event,
1034 .connect = evdev_connect,
1035 .disconnect = evdev_disconnect,
1036 .fops = &evdev_fops,
1037 .minor = EVDEV_MINOR_BASE,
1038 .name = "evdev",
1039 .id_table = evdev_ids,
1040};
1041
1042static int __init evdev_init(void)
1043{
1044 return input_register_handler(&evdev_handler);
1045}
1046
1047static void __exit evdev_exit(void)
1048{
1049 input_unregister_handler(&evdev_handler);
1050}
1051
1052module_init(evdev_init);
1053module_exit(evdev_exit);
1054
1055MODULE_AUTHOR("Vojtech Pavlik <[email protected]>");
1056MODULE_DESCRIPTION("Input driver event char devices");
1057MODULE_LICENSE("GPL");