projects/linux·blob v3.0-rc2 · refs

1012 lines · 22.5 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.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 unsigned int bufsize;
50 struct input_event buffer[];
51};
52
53static struct evdev *evdev_table[EVDEV_MINORS];
54static DEFINE_MUTEX(evdev_table_mutex);
55
56static void evdev_pass_event(struct evdev_client *client,
57 struct input_event *event)
58{
59 /* Interrupts are disabled, just acquire the lock. */
60 spin_lock(&client->buffer_lock);
61
62 client->buffer[client->head++] = *event;
63 client->head &= client->bufsize - 1;
64
65 if (unlikely(client->head == client->tail)) {
66 /*
67 * This effectively "drops" all unconsumed events, leaving
68 * EV_SYN/SYN_DROPPED plus the newest event in the queue.
69 */
70 client->tail = (client->head - 2) & (client->bufsize - 1);
71
72 client->buffer[client->tail].time = event->time;
73 client->buffer[client->tail].type = EV_SYN;
74 client->buffer[client->tail].code = SYN_DROPPED;
75 client->buffer[client->tail].value = 0;
76
77 client->packet_head = client->tail;
78 }
79
80 if (event->type == EV_SYN && event->code == SYN_REPORT) {
81 client->packet_head = client->head;
82 kill_fasync(&client->fasync, SIGIO, POLL_IN);
83 }
84
85 spin_unlock(&client->buffer_lock);
86}
87
88/*
89 * Pass incoming event to all connected clients.
90 */
91static void evdev_event(struct input_handle *handle,
92 unsigned int type, unsigned int code, int value)
93{
94 struct evdev *evdev = handle->private;
95 struct evdev_client *client;
96 struct input_event event;
97
98 do_gettimeofday(&event.time);
99 event.type = type;
100 event.code = code;
101 event.value = value;
102
103 rcu_read_lock();
104
105 client = rcu_dereference(evdev->grab);
106 if (client)
107 evdev_pass_event(client, &event);
108 else
109 list_for_each_entry_rcu(client, &evdev->client_list, node)
110 evdev_pass_event(client, &event);
111
112 rcu_read_unlock();
113
114 wake_up_interruptible(&evdev->wait);
115}
116
117static int evdev_fasync(int fd, struct file *file, int on)
118{
119 struct evdev_client *client = file->private_data;
120
121 return fasync_helper(fd, file, on, &client->fasync);
122}
123
124static int evdev_flush(struct file *file, fl_owner_t id)
125{
126 struct evdev_client *client = file->private_data;
127 struct evdev *evdev = client->evdev;
128 int retval;
129
130 retval = mutex_lock_interruptible(&evdev->mutex);
131 if (retval)
132 return retval;
133
134 if (!evdev->exist)
135 retval = -ENODEV;
136 else
137 retval = input_flush_device(&evdev->handle, file);
138
139 mutex_unlock(&evdev->mutex);
140 return retval;
141}
142
143static void evdev_free(struct device *dev)
144{
145 struct evdev *evdev = container_of(dev, struct evdev, dev);
146
147 input_put_device(evdev->handle.dev);
148 kfree(evdev);
149}
150
151/*
152 * Grabs an event device (along with underlying input device).
153 * This function is called with evdev->mutex taken.
154 */
155static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
156{
157 int error;
158
159 if (evdev->grab)
160 return -EBUSY;
161
162 error = input_grab_device(&evdev->handle);
163 if (error)
164 return error;
165
166 rcu_assign_pointer(evdev->grab, client);
167
168 return 0;
169}
170
171static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
172{
173 if (evdev->grab != client)
174 return -EINVAL;
175
176 rcu_assign_pointer(evdev->grab, NULL);
177 synchronize_rcu();
178 input_release_device(&evdev->handle);
179
180 return 0;
181}
182
183static void evdev_attach_client(struct evdev *evdev,
184 struct evdev_client *client)
185{
186 spin_lock(&evdev->client_lock);
187 list_add_tail_rcu(&client->node, &evdev->client_list);
188 spin_unlock(&evdev->client_lock);
189}
190
191static void evdev_detach_client(struct evdev *evdev,
192 struct evdev_client *client)
193{
194 spin_lock(&evdev->client_lock);
195 list_del_rcu(&client->node);
196 spin_unlock(&evdev->client_lock);
197 synchronize_rcu();
198}
199
200static int evdev_open_device(struct evdev *evdev)
201{
202 int retval;
203
204 retval = mutex_lock_interruptible(&evdev->mutex);
205 if (retval)
206 return retval;
207
208 if (!evdev->exist)
209 retval = -ENODEV;
210 else if (!evdev->open++) {
211 retval = input_open_device(&evdev->handle);
212 if (retval)
213 evdev->open--;
214 }
215
216 mutex_unlock(&evdev->mutex);
217 return retval;
218}
219
220static void evdev_close_device(struct evdev *evdev)
221{
222 mutex_lock(&evdev->mutex);
223
224 if (evdev->exist && !--evdev->open)
225 input_close_device(&evdev->handle);
226
227 mutex_unlock(&evdev->mutex);
228}
229
230/*
231 * Wake up users waiting for IO so they can disconnect from
232 * dead device.
233 */
234static void evdev_hangup(struct evdev *evdev)
235{
236 struct evdev_client *client;
237
238 spin_lock(&evdev->client_lock);
239 list_for_each_entry(client, &evdev->client_list, node)
240 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
241 spin_unlock(&evdev->client_lock);
242
243 wake_up_interruptible(&evdev->wait);
244}
245
246static int evdev_release(struct inode *inode, struct file *file)
247{
248 struct evdev_client *client = file->private_data;
249 struct evdev *evdev = client->evdev;
250
251 mutex_lock(&evdev->mutex);
252 if (evdev->grab == client)
253 evdev_ungrab(evdev, client);
254 mutex_unlock(&evdev->mutex);
255
256 evdev_detach_client(evdev, client);
257 kfree(client);
258
259 evdev_close_device(evdev);
260 put_device(&evdev->dev);
261
262 return 0;
263}
264
265static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
266{
267 unsigned int n_events =
268 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
269 EVDEV_MIN_BUFFER_SIZE);
270
271 return roundup_pow_of_two(n_events);
272}
273
274static int evdev_open(struct inode *inode, struct file *file)
275{
276 struct evdev *evdev;
277 struct evdev_client *client;
278 int i = iminor(inode) - EVDEV_MINOR_BASE;
279 unsigned int bufsize;
280 int error;
281
282 if (i >= EVDEV_MINORS)
283 return -ENODEV;
284
285 error = mutex_lock_interruptible(&evdev_table_mutex);
286 if (error)
287 return error;
288 evdev = evdev_table[i];
289 if (evdev)
290 get_device(&evdev->dev);
291 mutex_unlock(&evdev_table_mutex);
292
293 if (!evdev)
294 return -ENODEV;
295
296 bufsize = evdev_compute_buffer_size(evdev->handle.dev);
297
298 client = kzalloc(sizeof(struct evdev_client) +
299 bufsize * sizeof(struct input_event),
300 GFP_KERNEL);
301 if (!client) {
302 error = -ENOMEM;
303 goto err_put_evdev;
304 }
305
306 client->bufsize = bufsize;
307 spin_lock_init(&client->buffer_lock);
308 client->evdev = evdev;
309 evdev_attach_client(evdev, client);
310
311 error = evdev_open_device(evdev);
312 if (error)
313 goto err_free_client;
314
315 file->private_data = client;
316 nonseekable_open(inode, file);
317
318 return 0;
319
320 err_free_client:
321 evdev_detach_client(evdev, client);
322 kfree(client);
323 err_put_evdev:
324 put_device(&evdev->dev);
325 return error;
326}
327
328static ssize_t evdev_write(struct file *file, const char __user *buffer,
329 size_t count, loff_t *ppos)
330{
331 struct evdev_client *client = file->private_data;
332 struct evdev *evdev = client->evdev;
333 struct input_event event;
334 int retval;
335
336 if (count < input_event_size())
337 return -EINVAL;
338
339 retval = mutex_lock_interruptible(&evdev->mutex);
340 if (retval)
341 return retval;
342
343 if (!evdev->exist) {
344 retval = -ENODEV;
345 goto out;
346 }
347
348 do {
349 if (input_event_from_user(buffer + retval, &event)) {
350 retval = -EFAULT;
351 goto out;
352 }
353 retval += input_event_size();
354
355 input_inject_event(&evdev->handle,
356 event.type, event.code, event.value);
357 } while (retval + input_event_size() <= count);
358
359 out:
360 mutex_unlock(&evdev->mutex);
361 return retval;
362}
363
364static int evdev_fetch_next_event(struct evdev_client *client,
365 struct input_event *event)
366{
367 int have_event;
368
369 spin_lock_irq(&client->buffer_lock);
370
371 have_event = client->head != client->tail;
372 if (have_event) {
373 *event = client->buffer[client->tail++];
374 client->tail &= client->bufsize - 1;
375 }
376
377 spin_unlock_irq(&client->buffer_lock);
378
379 return have_event;
380}
381
382static ssize_t evdev_read(struct file *file, char __user *buffer,
383 size_t count, loff_t *ppos)
384{
385 struct evdev_client *client = file->private_data;
386 struct evdev *evdev = client->evdev;
387 struct input_event event;
388 int retval;
389
390 if (count < input_event_size())
391 return -EINVAL;
392
393 if (client->packet_head == client->tail && evdev->exist &&
394 (file->f_flags & O_NONBLOCK))
395 return -EAGAIN;
396
397 retval = wait_event_interruptible(evdev->wait,
398 client->packet_head != client->tail || !evdev->exist);
399 if (retval)
400 return retval;
401
402 if (!evdev->exist)
403 return -ENODEV;
404
405 while (retval + input_event_size() <= count &&
406 evdev_fetch_next_event(client, &event)) {
407
408 if (input_event_to_user(buffer + retval, &event))
409 return -EFAULT;
410
411 retval += input_event_size();
412 }
413
414 return retval;
415}
416
417/* No kernel lock - fine */
418static unsigned int evdev_poll(struct file *file, poll_table *wait)
419{
420 struct evdev_client *client = file->private_data;
421 struct evdev *evdev = client->evdev;
422 unsigned int mask;
423
424 poll_wait(file, &evdev->wait, wait);
425
426 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
427 if (client->packet_head != client->tail)
428 mask |= POLLIN | POLLRDNORM;
429
430 return mask;
431}
432
433#ifdef CONFIG_COMPAT
434
435#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
436#define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
437
438#ifdef __BIG_ENDIAN
439static int bits_to_user(unsigned long *bits, unsigned int maxbit,
440 unsigned int maxlen, void __user *p, int compat)
441{
442 int len, i;
443
444 if (compat) {
445 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
446 if (len > maxlen)
447 len = maxlen;
448
449 for (i = 0; i < len / sizeof(compat_long_t); i++)
450 if (copy_to_user((compat_long_t __user *) p + i,
451 (compat_long_t *) bits +
452 i + 1 - ((i % 2) << 1),
453 sizeof(compat_long_t)))
454 return -EFAULT;
455 } else {
456 len = BITS_TO_LONGS(maxbit) * sizeof(long);
457 if (len > maxlen)
458 len = maxlen;
459
460 if (copy_to_user(p, bits, len))
461 return -EFAULT;
462 }
463
464 return len;
465}
466#else
467static int bits_to_user(unsigned long *bits, unsigned int maxbit,
468 unsigned int maxlen, void __user *p, int compat)
469{
470 int len = compat ?
471 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
472 BITS_TO_LONGS(maxbit) * sizeof(long);
473
474 if (len > maxlen)
475 len = maxlen;
476
477 return copy_to_user(p, bits, len) ? -EFAULT : len;
478}
479#endif /* __BIG_ENDIAN */
480
481#else
482
483static int bits_to_user(unsigned long *bits, unsigned int maxbit,
484 unsigned int maxlen, void __user *p, int compat)
485{
486 int len = BITS_TO_LONGS(maxbit) * sizeof(long);
487
488 if (len > maxlen)
489 len = maxlen;
490
491 return copy_to_user(p, bits, len) ? -EFAULT : len;
492}
493
494#endif /* CONFIG_COMPAT */
495
496static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
497{
498 int len;
499
500 if (!str)
501 return -ENOENT;
502
503 len = strlen(str) + 1;
504 if (len > maxlen)
505 len = maxlen;
506
507 return copy_to_user(p, str, len) ? -EFAULT : len;
508}
509
510#define OLD_KEY_MAX 0x1ff
511static int handle_eviocgbit(struct input_dev *dev,
512 unsigned int type, unsigned int size,
513 void __user *p, int compat_mode)
514{
515 static unsigned long keymax_warn_time;
516 unsigned long *bits;
517 int len;
518
519 switch (type) {
520
521 case 0: bits = dev->evbit; len = EV_MAX; break;
522 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
523 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
524 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
525 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
526 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
527 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
528 case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
529 case EV_SW: bits = dev->swbit; len = SW_MAX; break;
530 default: return -EINVAL;
531 }
532
533 /*
534 * Work around bugs in userspace programs that like to do
535 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
536 * should be in bytes, not in bits.
537 */
538 if (type == EV_KEY && size == OLD_KEY_MAX) {
539 len = OLD_KEY_MAX;
540 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
541 pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
542 "limiting output to %zu bytes. See "
543 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
544 OLD_KEY_MAX,
545 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
546 }
547
548 return bits_to_user(bits, len, size, p, compat_mode);
549}
550#undef OLD_KEY_MAX
551
552static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
553{
554 struct input_keymap_entry ke = {
555 .len = sizeof(unsigned int),
556 .flags = 0,
557 };
558 int __user *ip = (int __user *)p;
559 int error;
560
561 /* legacy case */
562 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
563 return -EFAULT;
564
565 error = input_get_keycode(dev, &ke);
566 if (error)
567 return error;
568
569 if (put_user(ke.keycode, ip + 1))
570 return -EFAULT;
571
572 return 0;
573}
574
575static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
576{
577 struct input_keymap_entry ke;
578 int error;
579
580 if (copy_from_user(&ke, p, sizeof(ke)))
581 return -EFAULT;
582
583 error = input_get_keycode(dev, &ke);
584 if (error)
585 return error;
586
587 if (copy_to_user(p, &ke, sizeof(ke)))
588 return -EFAULT;
589
590 return 0;
591}
592
593static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
594{
595 struct input_keymap_entry ke = {
596 .len = sizeof(unsigned int),
597 .flags = 0,
598 };
599 int __user *ip = (int __user *)p;
600
601 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
602 return -EFAULT;
603
604 if (get_user(ke.keycode, ip + 1))
605 return -EFAULT;
606
607 return input_set_keycode(dev, &ke);
608}
609
610static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
611{
612 struct input_keymap_entry ke;
613
614 if (copy_from_user(&ke, p, sizeof(ke)))
615 return -EFAULT;
616
617 if (ke.len > sizeof(ke.scancode))
618 return -EINVAL;
619
620 return input_set_keycode(dev, &ke);
621}
622
623static long evdev_do_ioctl(struct file *file, unsigned int cmd,
624 void __user *p, int compat_mode)
625{
626 struct evdev_client *client = file->private_data;
627 struct evdev *evdev = client->evdev;
628 struct input_dev *dev = evdev->handle.dev;
629 struct input_absinfo abs;
630 struct ff_effect effect;
631 int __user *ip = (int __user *)p;
632 unsigned int i, t, u, v;
633 unsigned int size;
634 int error;
635
636 /* First we check for fixed-length commands */
637 switch (cmd) {
638
639 case EVIOCGVERSION:
640 return put_user(EV_VERSION, ip);
641
642 case EVIOCGID:
643 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
644 return -EFAULT;
645 return 0;
646
647 case EVIOCGREP:
648 if (!test_bit(EV_REP, dev->evbit))
649 return -ENOSYS;
650 if (put_user(dev->rep[REP_DELAY], ip))
651 return -EFAULT;
652 if (put_user(dev->rep[REP_PERIOD], ip + 1))
653 return -EFAULT;
654 return 0;
655
656 case EVIOCSREP:
657 if (!test_bit(EV_REP, dev->evbit))
658 return -ENOSYS;
659 if (get_user(u, ip))
660 return -EFAULT;
661 if (get_user(v, ip + 1))
662 return -EFAULT;
663
664 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
665 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
666
667 return 0;
668
669 case EVIOCRMFF:
670 return input_ff_erase(dev, (int)(unsigned long) p, file);
671
672 case EVIOCGEFFECTS:
673 i = test_bit(EV_FF, dev->evbit) ?
674 dev->ff->max_effects : 0;
675 if (put_user(i, ip))
676 return -EFAULT;
677 return 0;
678
679 case EVIOCGRAB:
680 if (p)
681 return evdev_grab(evdev, client);
682 else
683 return evdev_ungrab(evdev, client);
684
685 case EVIOCGKEYCODE:
686 return evdev_handle_get_keycode(dev, p);
687
688 case EVIOCSKEYCODE:
689 return evdev_handle_set_keycode(dev, p);
690
691 case EVIOCGKEYCODE_V2:
692 return evdev_handle_get_keycode_v2(dev, p);
693
694 case EVIOCSKEYCODE_V2:
695 return evdev_handle_set_keycode_v2(dev, p);
696 }
697
698 size = _IOC_SIZE(cmd);
699
700 /* Now check variable-length commands */
701#define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
702 switch (EVIOC_MASK_SIZE(cmd)) {
703
704 case EVIOCGPROP(0):
705 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
706 size, p, compat_mode);
707
708 case EVIOCGKEY(0):
709 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
710
711 case EVIOCGLED(0):
712 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
713
714 case EVIOCGSND(0):
715 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
716
717 case EVIOCGSW(0):
718 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
719
720 case EVIOCGNAME(0):
721 return str_to_user(dev->name, size, p);
722
723 case EVIOCGPHYS(0):
724 return str_to_user(dev->phys, size, p);
725
726 case EVIOCGUNIQ(0):
727 return str_to_user(dev->uniq, size, p);
728
729 case EVIOC_MASK_SIZE(EVIOCSFF):
730 if (input_ff_effect_from_user(p, size, &effect))
731 return -EFAULT;
732
733 error = input_ff_upload(dev, &effect, file);
734
735 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
736 return -EFAULT;
737
738 return error;
739 }
740
741 /* Multi-number variable-length handlers */
742 if (_IOC_TYPE(cmd) != 'E')
743 return -EINVAL;
744
745 if (_IOC_DIR(cmd) == _IOC_READ) {
746
747 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
748 return handle_eviocgbit(dev,
749 _IOC_NR(cmd) & EV_MAX, size,
750 p, compat_mode);
751
752 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
753
754 if (!dev->absinfo)
755 return -EINVAL;
756
757 t = _IOC_NR(cmd) & ABS_MAX;
758 abs = dev->absinfo[t];
759
760 if (copy_to_user(p, &abs, min_t(size_t,
761 size, sizeof(struct input_absinfo))))
762 return -EFAULT;
763
764 return 0;
765 }
766 }
767
768 if (_IOC_DIR(cmd) == _IOC_WRITE) {
769
770 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
771
772 if (!dev->absinfo)
773 return -EINVAL;
774
775 t = _IOC_NR(cmd) & ABS_MAX;
776
777 if (copy_from_user(&abs, p, min_t(size_t,
778 size, sizeof(struct input_absinfo))))
779 return -EFAULT;
780
781 if (size < sizeof(struct input_absinfo))
782 abs.resolution = 0;
783
784 /* We can't change number of reserved MT slots */
785 if (t == ABS_MT_SLOT)
786 return -EINVAL;
787
788 /*
789 * Take event lock to ensure that we are not
790 * changing device parameters in the middle
791 * of event.
792 */
793 spin_lock_irq(&dev->event_lock);
794 dev->absinfo[t] = abs;
795 spin_unlock_irq(&dev->event_lock);
796
797 return 0;
798 }
799 }
800
801 return -EINVAL;
802}
803
804static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
805 void __user *p, int compat_mode)
806{
807 struct evdev_client *client = file->private_data;
808 struct evdev *evdev = client->evdev;
809 int retval;
810
811 retval = mutex_lock_interruptible(&evdev->mutex);
812 if (retval)
813 return retval;
814
815 if (!evdev->exist) {
816 retval = -ENODEV;
817 goto out;
818 }
819
820 retval = evdev_do_ioctl(file, cmd, p, compat_mode);
821
822 out:
823 mutex_unlock(&evdev->mutex);
824 return retval;
825}
826
827static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
828{
829 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
830}
831
832#ifdef CONFIG_COMPAT
833static long evdev_ioctl_compat(struct file *file,
834 unsigned int cmd, unsigned long arg)
835{
836 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
837}
838#endif
839
840static const struct file_operations evdev_fops = {
841 .owner = THIS_MODULE,
842 .read = evdev_read,
843 .write = evdev_write,
844 .poll = evdev_poll,
845 .open = evdev_open,
846 .release = evdev_release,
847 .unlocked_ioctl = evdev_ioctl,
848#ifdef CONFIG_COMPAT
849 .compat_ioctl = evdev_ioctl_compat,
850#endif
851 .fasync = evdev_fasync,
852 .flush = evdev_flush,
853 .llseek = no_llseek,
854};
855
856static int evdev_install_chrdev(struct evdev *evdev)
857{
858 /*
859 * No need to do any locking here as calls to connect and
860 * disconnect are serialized by the input core
861 */
862 evdev_table[evdev->minor] = evdev;
863 return 0;
864}
865
866static void evdev_remove_chrdev(struct evdev *evdev)
867{
868 /*
869 * Lock evdev table to prevent race with evdev_open()
870 */
871 mutex_lock(&evdev_table_mutex);
872 evdev_table[evdev->minor] = NULL;
873 mutex_unlock(&evdev_table_mutex);
874}
875
876/*
877 * Mark device non-existent. This disables writes, ioctls and
878 * prevents new users from opening the device. Already posted
879 * blocking reads will stay, however new ones will fail.
880 */
881static void evdev_mark_dead(struct evdev *evdev)
882{
883 mutex_lock(&evdev->mutex);
884 evdev->exist = false;
885 mutex_unlock(&evdev->mutex);
886}
887
888static void evdev_cleanup(struct evdev *evdev)
889{
890 struct input_handle *handle = &evdev->handle;
891
892 evdev_mark_dead(evdev);
893 evdev_hangup(evdev);
894 evdev_remove_chrdev(evdev);
895
896 /* evdev is marked dead so no one else accesses evdev->open */
897 if (evdev->open) {
898 input_flush_device(handle, NULL);
899 input_close_device(handle);
900 }
901}
902
903/*
904 * Create new evdev device. Note that input core serializes calls
905 * to connect and disconnect so we don't need to lock evdev_table here.
906 */
907static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
908 const struct input_device_id *id)
909{
910 struct evdev *evdev;
911 int minor;
912 int error;
913
914 for (minor = 0; minor < EVDEV_MINORS; minor++)
915 if (!evdev_table[minor])
916 break;
917
918 if (minor == EVDEV_MINORS) {
919 pr_err("no more free evdev devices\n");
920 return -ENFILE;
921 }
922
923 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
924 if (!evdev)
925 return -ENOMEM;
926
927 INIT_LIST_HEAD(&evdev->client_list);
928 spin_lock_init(&evdev->client_lock);
929 mutex_init(&evdev->mutex);
930 init_waitqueue_head(&evdev->wait);
931
932 dev_set_name(&evdev->dev, "event%d", minor);
933 evdev->exist = true;
934 evdev->minor = minor;
935
936 evdev->handle.dev = input_get_device(dev);
937 evdev->handle.name = dev_name(&evdev->dev);
938 evdev->handle.handler = handler;
939 evdev->handle.private = evdev;
940
941 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
942 evdev->dev.class = &input_class;
943 evdev->dev.parent = &dev->dev;
944 evdev->dev.release = evdev_free;
945 device_initialize(&evdev->dev);
946
947 error = input_register_handle(&evdev->handle);
948 if (error)
949 goto err_free_evdev;
950
951 error = evdev_install_chrdev(evdev);
952 if (error)
953 goto err_unregister_handle;
954
955 error = device_add(&evdev->dev);
956 if (error)
957 goto err_cleanup_evdev;
958
959 return 0;
960
961 err_cleanup_evdev:
962 evdev_cleanup(evdev);
963 err_unregister_handle:
964 input_unregister_handle(&evdev->handle);
965 err_free_evdev:
966 put_device(&evdev->dev);
967 return error;
968}
969
970static void evdev_disconnect(struct input_handle *handle)
971{
972 struct evdev *evdev = handle->private;
973
974 device_del(&evdev->dev);
975 evdev_cleanup(evdev);
976 input_unregister_handle(handle);
977 put_device(&evdev->dev);
978}
979
980static const struct input_device_id evdev_ids[] = {
981 { .driver_info = 1 }, /* Matches all devices */
982 { }, /* Terminating zero entry */
983};
984
985MODULE_DEVICE_TABLE(input, evdev_ids);
986
987static struct input_handler evdev_handler = {
988 .event = evdev_event,
989 .connect = evdev_connect,
990 .disconnect = evdev_disconnect,
991 .fops = &evdev_fops,
992 .minor = EVDEV_MINOR_BASE,
993 .name = "evdev",
994 .id_table = evdev_ids,
995};
996
997static int __init evdev_init(void)
998{
999 return input_register_handler(&evdev_handler);
1000}
1001
1002static void __exit evdev_exit(void)
1003{
1004 input_unregister_handler(&evdev_handler);
1005}
1006
1007module_init(evdev_init);
1008module_exit(evdev_exit);
1009
1010MODULE_AUTHOR("Vojtech Pavlik <[email protected]>");
1011MODULE_DESCRIPTION("Input driver event char devices");
1012MODULE_LICENSE("GPL");