projects/linux·blob v2.6.36 · refs

929 lines · 20.5 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 EVDEV_MINOR_BASE 64
12#define EVDEV_MINORS 32
13#define EVDEV_MIN_BUFFER_SIZE 64U
14#define EVDEV_BUF_PACKETS 8
15
16#include <linux/poll.h>
17#include <linux/sched.h>
18#include <linux/slab.h>
19#include <linux/module.h>
20#include <linux/init.h>
21#include <linux/input.h>
22#include <linux/major.h>
23#include <linux/device.h>
24#include "input-compat.h"
25
26struct evdev {
27 int open;
28 int minor;
29 struct input_handle handle;
30 wait_queue_head_t wait;
31 struct evdev_client *grab;
32 struct list_head client_list;
33 spinlock_t client_lock; /* protects client_list */
34 struct mutex mutex;
35 struct device dev;
36 bool exist;
37};
38
39struct evdev_client {
40 int head;
41 int tail;
42 spinlock_t buffer_lock; /* protects access to buffer, head and tail */
43 struct fasync_struct *fasync;
44 struct evdev *evdev;
45 struct list_head node;
46 int bufsize;
47 struct input_event buffer[];
48};
49
50static struct evdev *evdev_table[EVDEV_MINORS];
51static DEFINE_MUTEX(evdev_table_mutex);
52
53static void evdev_pass_event(struct evdev_client *client,
54 struct input_event *event)
55{
56 /*
57 * Interrupts are disabled, just acquire the lock.
58 * Make sure we don't leave with the client buffer
59 * "empty" by having client->head == client->tail.
60 */
61 spin_lock(&client->buffer_lock);
62 do {
63 client->buffer[client->head++] = *event;
64 client->head &= client->bufsize - 1;
65 } while (client->head == client->tail);
66 spin_unlock(&client->buffer_lock);
67
68 if (event->type == EV_SYN)
69 kill_fasync(&client->fasync, SIGIO, POLL_IN);
70}
71
72/*
73 * Pass incoming event to all connected clients.
74 */
75static void evdev_event(struct input_handle *handle,
76 unsigned int type, unsigned int code, int value)
77{
78 struct evdev *evdev = handle->private;
79 struct evdev_client *client;
80 struct input_event event;
81
82 do_gettimeofday(&event.time);
83 event.type = type;
84 event.code = code;
85 event.value = value;
86
87 rcu_read_lock();
88
89 client = rcu_dereference(evdev->grab);
90 if (client)
91 evdev_pass_event(client, &event);
92 else
93 list_for_each_entry_rcu(client, &evdev->client_list, node)
94 evdev_pass_event(client, &event);
95
96 rcu_read_unlock();
97
98 wake_up_interruptible(&evdev->wait);
99}
100
101static int evdev_fasync(int fd, struct file *file, int on)
102{
103 struct evdev_client *client = file->private_data;
104
105 return fasync_helper(fd, file, on, &client->fasync);
106}
107
108static int evdev_flush(struct file *file, fl_owner_t id)
109{
110 struct evdev_client *client = file->private_data;
111 struct evdev *evdev = client->evdev;
112 int retval;
113
114 retval = mutex_lock_interruptible(&evdev->mutex);
115 if (retval)
116 return retval;
117
118 if (!evdev->exist)
119 retval = -ENODEV;
120 else
121 retval = input_flush_device(&evdev->handle, file);
122
123 mutex_unlock(&evdev->mutex);
124 return retval;
125}
126
127static void evdev_free(struct device *dev)
128{
129 struct evdev *evdev = container_of(dev, struct evdev, dev);
130
131 input_put_device(evdev->handle.dev);
132 kfree(evdev);
133}
134
135/*
136 * Grabs an event device (along with underlying input device).
137 * This function is called with evdev->mutex taken.
138 */
139static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
140{
141 int error;
142
143 if (evdev->grab)
144 return -EBUSY;
145
146 error = input_grab_device(&evdev->handle);
147 if (error)
148 return error;
149
150 rcu_assign_pointer(evdev->grab, client);
151 synchronize_rcu();
152
153 return 0;
154}
155
156static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
157{
158 if (evdev->grab != client)
159 return -EINVAL;
160
161 rcu_assign_pointer(evdev->grab, NULL);
162 synchronize_rcu();
163 input_release_device(&evdev->handle);
164
165 return 0;
166}
167
168static void evdev_attach_client(struct evdev *evdev,
169 struct evdev_client *client)
170{
171 spin_lock(&evdev->client_lock);
172 list_add_tail_rcu(&client->node, &evdev->client_list);
173 spin_unlock(&evdev->client_lock);
174 synchronize_rcu();
175}
176
177static void evdev_detach_client(struct evdev *evdev,
178 struct evdev_client *client)
179{
180 spin_lock(&evdev->client_lock);
181 list_del_rcu(&client->node);
182 spin_unlock(&evdev->client_lock);
183 synchronize_rcu();
184}
185
186static int evdev_open_device(struct evdev *evdev)
187{
188 int retval;
189
190 retval = mutex_lock_interruptible(&evdev->mutex);
191 if (retval)
192 return retval;
193
194 if (!evdev->exist)
195 retval = -ENODEV;
196 else if (!evdev->open++) {
197 retval = input_open_device(&evdev->handle);
198 if (retval)
199 evdev->open--;
200 }
201
202 mutex_unlock(&evdev->mutex);
203 return retval;
204}
205
206static void evdev_close_device(struct evdev *evdev)
207{
208 mutex_lock(&evdev->mutex);
209
210 if (evdev->exist && !--evdev->open)
211 input_close_device(&evdev->handle);
212
213 mutex_unlock(&evdev->mutex);
214}
215
216/*
217 * Wake up users waiting for IO so they can disconnect from
218 * dead device.
219 */
220static void evdev_hangup(struct evdev *evdev)
221{
222 struct evdev_client *client;
223
224 spin_lock(&evdev->client_lock);
225 list_for_each_entry(client, &evdev->client_list, node)
226 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
227 spin_unlock(&evdev->client_lock);
228
229 wake_up_interruptible(&evdev->wait);
230}
231
232static int evdev_release(struct inode *inode, struct file *file)
233{
234 struct evdev_client *client = file->private_data;
235 struct evdev *evdev = client->evdev;
236
237 mutex_lock(&evdev->mutex);
238 if (evdev->grab == client)
239 evdev_ungrab(evdev, client);
240 mutex_unlock(&evdev->mutex);
241
242 evdev_detach_client(evdev, client);
243 kfree(client);
244
245 evdev_close_device(evdev);
246 put_device(&evdev->dev);
247
248 return 0;
249}
250
251static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
252{
253 unsigned int n_events =
254 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
255 EVDEV_MIN_BUFFER_SIZE);
256
257 return roundup_pow_of_two(n_events);
258}
259
260static int evdev_open(struct inode *inode, struct file *file)
261{
262 struct evdev *evdev;
263 struct evdev_client *client;
264 int i = iminor(inode) - EVDEV_MINOR_BASE;
265 unsigned int bufsize;
266 int error;
267
268 if (i >= EVDEV_MINORS)
269 return -ENODEV;
270
271 error = mutex_lock_interruptible(&evdev_table_mutex);
272 if (error)
273 return error;
274 evdev = evdev_table[i];
275 if (evdev)
276 get_device(&evdev->dev);
277 mutex_unlock(&evdev_table_mutex);
278
279 if (!evdev)
280 return -ENODEV;
281
282 bufsize = evdev_compute_buffer_size(evdev->handle.dev);
283
284 client = kzalloc(sizeof(struct evdev_client) +
285 bufsize * sizeof(struct input_event),
286 GFP_KERNEL);
287 if (!client) {
288 error = -ENOMEM;
289 goto err_put_evdev;
290 }
291
292 client->bufsize = bufsize;
293 spin_lock_init(&client->buffer_lock);
294 client->evdev = evdev;
295 evdev_attach_client(evdev, client);
296
297 error = evdev_open_device(evdev);
298 if (error)
299 goto err_free_client;
300
301 file->private_data = client;
302 nonseekable_open(inode, file);
303
304 return 0;
305
306 err_free_client:
307 evdev_detach_client(evdev, client);
308 kfree(client);
309 err_put_evdev:
310 put_device(&evdev->dev);
311 return error;
312}
313
314static ssize_t evdev_write(struct file *file, const char __user *buffer,
315 size_t count, loff_t *ppos)
316{
317 struct evdev_client *client = file->private_data;
318 struct evdev *evdev = client->evdev;
319 struct input_event event;
320 int retval;
321
322 retval = mutex_lock_interruptible(&evdev->mutex);
323 if (retval)
324 return retval;
325
326 if (!evdev->exist) {
327 retval = -ENODEV;
328 goto out;
329 }
330
331 while (retval < count) {
332
333 if (input_event_from_user(buffer + retval, &event)) {
334 retval = -EFAULT;
335 goto out;
336 }
337
338 input_inject_event(&evdev->handle,
339 event.type, event.code, event.value);
340 retval += input_event_size();
341 }
342
343 out:
344 mutex_unlock(&evdev->mutex);
345 return retval;
346}
347
348static int evdev_fetch_next_event(struct evdev_client *client,
349 struct input_event *event)
350{
351 int have_event;
352
353 spin_lock_irq(&client->buffer_lock);
354
355 have_event = client->head != client->tail;
356 if (have_event) {
357 *event = client->buffer[client->tail++];
358 client->tail &= client->bufsize - 1;
359 }
360
361 spin_unlock_irq(&client->buffer_lock);
362
363 return have_event;
364}
365
366static ssize_t evdev_read(struct file *file, char __user *buffer,
367 size_t count, loff_t *ppos)
368{
369 struct evdev_client *client = file->private_data;
370 struct evdev *evdev = client->evdev;
371 struct input_event event;
372 int retval;
373
374 if (count < input_event_size())
375 return -EINVAL;
376
377 if (client->head == client->tail && evdev->exist &&
378 (file->f_flags & O_NONBLOCK))
379 return -EAGAIN;
380
381 retval = wait_event_interruptible(evdev->wait,
382 client->head != client->tail || !evdev->exist);
383 if (retval)
384 return retval;
385
386 if (!evdev->exist)
387 return -ENODEV;
388
389 while (retval + input_event_size() <= count &&
390 evdev_fetch_next_event(client, &event)) {
391
392 if (input_event_to_user(buffer + retval, &event))
393 return -EFAULT;
394
395 retval += input_event_size();
396 }
397
398 return retval;
399}
400
401/* No kernel lock - fine */
402static unsigned int evdev_poll(struct file *file, poll_table *wait)
403{
404 struct evdev_client *client = file->private_data;
405 struct evdev *evdev = client->evdev;
406 unsigned int mask;
407
408 poll_wait(file, &evdev->wait, wait);
409
410 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
411 if (client->head != client->tail)
412 mask |= POLLIN | POLLRDNORM;
413
414 return mask;
415}
416
417#ifdef CONFIG_COMPAT
418
419#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
420#define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
421
422#ifdef __BIG_ENDIAN
423static int bits_to_user(unsigned long *bits, unsigned int maxbit,
424 unsigned int maxlen, void __user *p, int compat)
425{
426 int len, i;
427
428 if (compat) {
429 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
430 if (len > maxlen)
431 len = maxlen;
432
433 for (i = 0; i < len / sizeof(compat_long_t); i++)
434 if (copy_to_user((compat_long_t __user *) p + i,
435 (compat_long_t *) bits +
436 i + 1 - ((i % 2) << 1),
437 sizeof(compat_long_t)))
438 return -EFAULT;
439 } else {
440 len = BITS_TO_LONGS(maxbit) * sizeof(long);
441 if (len > maxlen)
442 len = maxlen;
443
444 if (copy_to_user(p, bits, len))
445 return -EFAULT;
446 }
447
448 return len;
449}
450#else
451static int bits_to_user(unsigned long *bits, unsigned int maxbit,
452 unsigned int maxlen, void __user *p, int compat)
453{
454 int len = compat ?
455 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
456 BITS_TO_LONGS(maxbit) * sizeof(long);
457
458 if (len > maxlen)
459 len = maxlen;
460
461 return copy_to_user(p, bits, len) ? -EFAULT : len;
462}
463#endif /* __BIG_ENDIAN */
464
465#else
466
467static int bits_to_user(unsigned long *bits, unsigned int maxbit,
468 unsigned int maxlen, void __user *p, int compat)
469{
470 int len = BITS_TO_LONGS(maxbit) * sizeof(long);
471
472 if (len > maxlen)
473 len = maxlen;
474
475 return copy_to_user(p, bits, len) ? -EFAULT : len;
476}
477
478#endif /* CONFIG_COMPAT */
479
480static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
481{
482 int len;
483
484 if (!str)
485 return -ENOENT;
486
487 len = strlen(str) + 1;
488 if (len > maxlen)
489 len = maxlen;
490
491 return copy_to_user(p, str, len) ? -EFAULT : len;
492}
493
494#define OLD_KEY_MAX 0x1ff
495static int handle_eviocgbit(struct input_dev *dev,
496 unsigned int type, unsigned int size,
497 void __user *p, int compat_mode)
498{
499 static unsigned long keymax_warn_time;
500 unsigned long *bits;
501 int len;
502
503 switch (type) {
504
505 case 0: bits = dev->evbit; len = EV_MAX; break;
506 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
507 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
508 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
509 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
510 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
511 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
512 case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
513 case EV_SW: bits = dev->swbit; len = SW_MAX; break;
514 default: return -EINVAL;
515 }
516
517 /*
518 * Work around bugs in userspace programs that like to do
519 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
520 * should be in bytes, not in bits.
521 */
522 if (type == EV_KEY && size == OLD_KEY_MAX) {
523 len = OLD_KEY_MAX;
524 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
525 printk(KERN_WARNING
526 "evdev.c(EVIOCGBIT): Suspicious buffer size %u, "
527 "limiting output to %zu bytes. See "
528 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
529 OLD_KEY_MAX,
530 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
531 }
532
533 return bits_to_user(bits, len, size, p, compat_mode);
534}
535#undef OLD_KEY_MAX
536
537static long evdev_do_ioctl(struct file *file, unsigned int cmd,
538 void __user *p, int compat_mode)
539{
540 struct evdev_client *client = file->private_data;
541 struct evdev *evdev = client->evdev;
542 struct input_dev *dev = evdev->handle.dev;
543 struct input_absinfo abs;
544 struct ff_effect effect;
545 int __user *ip = (int __user *)p;
546 unsigned int i, t, u, v;
547 unsigned int size;
548 int error;
549
550 /* First we check for fixed-length commands */
551 switch (cmd) {
552
553 case EVIOCGVERSION:
554 return put_user(EV_VERSION, ip);
555
556 case EVIOCGID:
557 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
558 return -EFAULT;
559 return 0;
560
561 case EVIOCGREP:
562 if (!test_bit(EV_REP, dev->evbit))
563 return -ENOSYS;
564 if (put_user(dev->rep[REP_DELAY], ip))
565 return -EFAULT;
566 if (put_user(dev->rep[REP_PERIOD], ip + 1))
567 return -EFAULT;
568 return 0;
569
570 case EVIOCSREP:
571 if (!test_bit(EV_REP, dev->evbit))
572 return -ENOSYS;
573 if (get_user(u, ip))
574 return -EFAULT;
575 if (get_user(v, ip + 1))
576 return -EFAULT;
577
578 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
579 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
580
581 return 0;
582
583 case EVIOCGKEYCODE:
584 if (get_user(t, ip))
585 return -EFAULT;
586
587 error = input_get_keycode(dev, t, &v);
588 if (error)
589 return error;
590
591 if (put_user(v, ip + 1))
592 return -EFAULT;
593
594 return 0;
595
596 case EVIOCSKEYCODE:
597 if (get_user(t, ip) || get_user(v, ip + 1))
598 return -EFAULT;
599
600 return input_set_keycode(dev, t, v);
601
602 case EVIOCRMFF:
603 return input_ff_erase(dev, (int)(unsigned long) p, file);
604
605 case EVIOCGEFFECTS:
606 i = test_bit(EV_FF, dev->evbit) ?
607 dev->ff->max_effects : 0;
608 if (put_user(i, ip))
609 return -EFAULT;
610 return 0;
611
612 case EVIOCGRAB:
613 if (p)
614 return evdev_grab(evdev, client);
615 else
616 return evdev_ungrab(evdev, client);
617 }
618
619 size = _IOC_SIZE(cmd);
620
621 /* Now check variable-length commands */
622#define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
623
624 switch (EVIOC_MASK_SIZE(cmd)) {
625
626 case EVIOCGKEY(0):
627 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
628
629 case EVIOCGLED(0):
630 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
631
632 case EVIOCGSND(0):
633 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
634
635 case EVIOCGSW(0):
636 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
637
638 case EVIOCGNAME(0):
639 return str_to_user(dev->name, size, p);
640
641 case EVIOCGPHYS(0):
642 return str_to_user(dev->phys, size, p);
643
644 case EVIOCGUNIQ(0):
645 return str_to_user(dev->uniq, size, p);
646
647 case EVIOC_MASK_SIZE(EVIOCSFF):
648 if (input_ff_effect_from_user(p, size, &effect))
649 return -EFAULT;
650
651 error = input_ff_upload(dev, &effect, file);
652
653 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
654 return -EFAULT;
655
656 return error;
657 }
658
659 /* Multi-number variable-length handlers */
660 if (_IOC_TYPE(cmd) != 'E')
661 return -EINVAL;
662
663 if (_IOC_DIR(cmd) == _IOC_READ) {
664
665 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
666 return handle_eviocgbit(dev,
667 _IOC_NR(cmd) & EV_MAX, size,
668 p, compat_mode);
669
670 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
671
672 if (!dev->absinfo)
673 return -EINVAL;
674
675 t = _IOC_NR(cmd) & ABS_MAX;
676 abs = dev->absinfo[t];
677
678 if (copy_to_user(p, &abs, min_t(size_t,
679 size, sizeof(struct input_absinfo))))
680 return -EFAULT;
681
682 return 0;
683 }
684 }
685
686 if (_IOC_DIR(cmd) == _IOC_WRITE) {
687
688 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
689
690 if (!dev->absinfo)
691 return -EINVAL;
692
693 t = _IOC_NR(cmd) & ABS_MAX;
694
695 if (copy_from_user(&abs, p, min_t(size_t,
696 size, sizeof(struct input_absinfo))))
697 return -EFAULT;
698
699 if (size < sizeof(struct input_absinfo))
700 abs.resolution = 0;
701
702 /* We can't change number of reserved MT slots */
703 if (t == ABS_MT_SLOT)
704 return -EINVAL;
705
706 /*
707 * Take event lock to ensure that we are not
708 * changing device parameters in the middle
709 * of event.
710 */
711 spin_lock_irq(&dev->event_lock);
712 dev->absinfo[t] = abs;
713 spin_unlock_irq(&dev->event_lock);
714
715 return 0;
716 }
717 }
718
719 return -EINVAL;
720}
721
722static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
723 void __user *p, int compat_mode)
724{
725 struct evdev_client *client = file->private_data;
726 struct evdev *evdev = client->evdev;
727 int retval;
728
729 retval = mutex_lock_interruptible(&evdev->mutex);
730 if (retval)
731 return retval;
732
733 if (!evdev->exist) {
734 retval = -ENODEV;
735 goto out;
736 }
737
738 retval = evdev_do_ioctl(file, cmd, p, compat_mode);
739
740 out:
741 mutex_unlock(&evdev->mutex);
742 return retval;
743}
744
745static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
746{
747 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
748}
749
750#ifdef CONFIG_COMPAT
751static long evdev_ioctl_compat(struct file *file,
752 unsigned int cmd, unsigned long arg)
753{
754 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
755}
756#endif
757
758static const struct file_operations evdev_fops = {
759 .owner = THIS_MODULE,
760 .read = evdev_read,
761 .write = evdev_write,
762 .poll = evdev_poll,
763 .open = evdev_open,
764 .release = evdev_release,
765 .unlocked_ioctl = evdev_ioctl,
766#ifdef CONFIG_COMPAT
767 .compat_ioctl = evdev_ioctl_compat,
768#endif
769 .fasync = evdev_fasync,
770 .flush = evdev_flush
771};
772
773static int evdev_install_chrdev(struct evdev *evdev)
774{
775 /*
776 * No need to do any locking here as calls to connect and
777 * disconnect are serialized by the input core
778 */
779 evdev_table[evdev->minor] = evdev;
780 return 0;
781}
782
783static void evdev_remove_chrdev(struct evdev *evdev)
784{
785 /*
786 * Lock evdev table to prevent race with evdev_open()
787 */
788 mutex_lock(&evdev_table_mutex);
789 evdev_table[evdev->minor] = NULL;
790 mutex_unlock(&evdev_table_mutex);
791}
792
793/*
794 * Mark device non-existent. This disables writes, ioctls and
795 * prevents new users from opening the device. Already posted
796 * blocking reads will stay, however new ones will fail.
797 */
798static void evdev_mark_dead(struct evdev *evdev)
799{
800 mutex_lock(&evdev->mutex);
801 evdev->exist = false;
802 mutex_unlock(&evdev->mutex);
803}
804
805static void evdev_cleanup(struct evdev *evdev)
806{
807 struct input_handle *handle = &evdev->handle;
808
809 evdev_mark_dead(evdev);
810 evdev_hangup(evdev);
811 evdev_remove_chrdev(evdev);
812
813 /* evdev is marked dead so no one else accesses evdev->open */
814 if (evdev->open) {
815 input_flush_device(handle, NULL);
816 input_close_device(handle);
817 }
818}
819
820/*
821 * Create new evdev device. Note that input core serializes calls
822 * to connect and disconnect so we don't need to lock evdev_table here.
823 */
824static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
825 const struct input_device_id *id)
826{
827 struct evdev *evdev;
828 int minor;
829 int error;
830
831 for (minor = 0; minor < EVDEV_MINORS; minor++)
832 if (!evdev_table[minor])
833 break;
834
835 if (minor == EVDEV_MINORS) {
836 printk(KERN_ERR "evdev: no more free evdev devices\n");
837 return -ENFILE;
838 }
839
840 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
841 if (!evdev)
842 return -ENOMEM;
843
844 INIT_LIST_HEAD(&evdev->client_list);
845 spin_lock_init(&evdev->client_lock);
846 mutex_init(&evdev->mutex);
847 init_waitqueue_head(&evdev->wait);
848
849 dev_set_name(&evdev->dev, "event%d", minor);
850 evdev->exist = true;
851 evdev->minor = minor;
852
853 evdev->handle.dev = input_get_device(dev);
854 evdev->handle.name = dev_name(&evdev->dev);
855 evdev->handle.handler = handler;
856 evdev->handle.private = evdev;
857
858 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
859 evdev->dev.class = &input_class;
860 evdev->dev.parent = &dev->dev;
861 evdev->dev.release = evdev_free;
862 device_initialize(&evdev->dev);
863
864 error = input_register_handle(&evdev->handle);
865 if (error)
866 goto err_free_evdev;
867
868 error = evdev_install_chrdev(evdev);
869 if (error)
870 goto err_unregister_handle;
871
872 error = device_add(&evdev->dev);
873 if (error)
874 goto err_cleanup_evdev;
875
876 return 0;
877
878 err_cleanup_evdev:
879 evdev_cleanup(evdev);
880 err_unregister_handle:
881 input_unregister_handle(&evdev->handle);
882 err_free_evdev:
883 put_device(&evdev->dev);
884 return error;
885}
886
887static void evdev_disconnect(struct input_handle *handle)
888{
889 struct evdev *evdev = handle->private;
890
891 device_del(&evdev->dev);
892 evdev_cleanup(evdev);
893 input_unregister_handle(handle);
894 put_device(&evdev->dev);
895}
896
897static const struct input_device_id evdev_ids[] = {
898 { .driver_info = 1 }, /* Matches all devices */
899 { }, /* Terminating zero entry */
900};
901
902MODULE_DEVICE_TABLE(input, evdev_ids);
903
904static struct input_handler evdev_handler = {
905 .event = evdev_event,
906 .connect = evdev_connect,
907 .disconnect = evdev_disconnect,
908 .fops = &evdev_fops,
909 .minor = EVDEV_MINOR_BASE,
910 .name = "evdev",
911 .id_table = evdev_ids,
912};
913
914static int __init evdev_init(void)
915{
916 return input_register_handler(&evdev_handler);
917}
918
919static void __exit evdev_exit(void)
920{
921 input_unregister_handler(&evdev_handler);
922}
923
924module_init(evdev_init);
925module_exit(evdev_exit);
926
927MODULE_AUTHOR("Vojtech Pavlik <[email protected]>");
928MODULE_DESCRIPTION("Input driver event char devices");
929MODULE_LICENSE("GPL");