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KVM: Don't spin on virt instruction faults during reboot
[linux-2.6.git] / drivers / input / evdev.c
blob68f09a868434b52a6522c147dce8125f42f6505f
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
26 struct evdev {
27 int open;
28 int minor;
29 struct input_handle handle;
30 wait_queue_head_t wait;
31 struct evdev_client __rcu *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
39 struct 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
50 static struct evdev *evdev_table[EVDEV_MINORS];
51 static DEFINE_MUTEX(evdev_table_mutex);
52
53 static 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 */
75 static 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
101 static 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
108 static 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
127 static 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 */
139 static 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
156 static 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
168 static 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
177 static 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
186 static 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
206 static 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 */
220 static 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
232 static 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
251 static 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
260 static 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
314 static 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
348 static 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
366 static 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 */
402 static 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
423 static 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
451 static 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
467 static 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
480 static 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
495 static 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
537 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
538 {
539 struct input_keymap_entry ke = {
540 .len = sizeof(unsigned int),
541 .flags = 0,
542 };
543 int __user *ip = (int __user *)p;
544 int error;
545
546 /* legacy case */
547 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
548 return -EFAULT;
549
550 error = input_get_keycode(dev, &ke);
551 if (error)
552 return error;
553
554 if (put_user(ke.keycode, ip + 1))
555 return -EFAULT;
556
557 return 0;
558 }
559
560 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
561 {
562 struct input_keymap_entry ke;
563 int error;
564
565 if (copy_from_user(&ke, p, sizeof(ke)))
566 return -EFAULT;
567
568 error = input_get_keycode(dev, &ke);
569 if (error)
570 return error;
571
572 if (copy_to_user(p, &ke, sizeof(ke)))
573 return -EFAULT;
574
575 return 0;
576 }
577
578 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
579 {
580 struct input_keymap_entry ke = {
581 .len = sizeof(unsigned int),
582 .flags = 0,
583 };
584 int __user *ip = (int __user *)p;
585
586 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
587 return -EFAULT;
588
589 if (get_user(ke.keycode, ip + 1))
590 return -EFAULT;
591
592 return input_set_keycode(dev, &ke);
593 }
594
595 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
596 {
597 struct input_keymap_entry ke;
598
599 if (copy_from_user(&ke, p, sizeof(ke)))
600 return -EFAULT;
601
602 if (ke.len > sizeof(ke.scancode))
603 return -EINVAL;
604
605 return input_set_keycode(dev, &ke);
606 }
607
608 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
609 void __user *p, int compat_mode)
610 {
611 struct evdev_client *client = file->private_data;
612 struct evdev *evdev = client->evdev;
613 struct input_dev *dev = evdev->handle.dev;
614 struct input_absinfo abs;
615 struct ff_effect effect;
616 int __user *ip = (int __user *)p;
617 unsigned int i, t, u, v;
618 unsigned int size;
619 int error;
620
621 /* First we check for fixed-length commands */
622 switch (cmd) {
623
624 case EVIOCGVERSION:
625 return put_user(EV_VERSION, ip);
626
627 case EVIOCGID:
628 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
629 return -EFAULT;
630 return 0;
631
632 case EVIOCGREP:
633 if (!test_bit(EV_REP, dev->evbit))
634 return -ENOSYS;
635 if (put_user(dev->rep[REP_DELAY], ip))
636 return -EFAULT;
637 if (put_user(dev->rep[REP_PERIOD], ip + 1))
638 return -EFAULT;
639 return 0;
640
641 case EVIOCSREP:
642 if (!test_bit(EV_REP, dev->evbit))
643 return -ENOSYS;
644 if (get_user(u, ip))
645 return -EFAULT;
646 if (get_user(v, ip + 1))
647 return -EFAULT;
648
649 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
650 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
651
652 return 0;
653
654 case EVIOCRMFF:
655 return input_ff_erase(dev, (int)(unsigned long) p, file);
656
657 case EVIOCGEFFECTS:
658 i = test_bit(EV_FF, dev->evbit) ?
659 dev->ff->max_effects : 0;
660 if (put_user(i, ip))
661 return -EFAULT;
662 return 0;
663
664 case EVIOCGRAB:
665 if (p)
666 return evdev_grab(evdev, client);
667 else
668 return evdev_ungrab(evdev, client);
669
670 case EVIOCGKEYCODE:
671 return evdev_handle_get_keycode(dev, p);
672
673 case EVIOCSKEYCODE:
674 return evdev_handle_set_keycode(dev, p);
675
676 case EVIOCGKEYCODE_V2:
677 return evdev_handle_get_keycode_v2(dev, p);
678
679 case EVIOCSKEYCODE_V2:
680 return evdev_handle_set_keycode_v2(dev, p);
681 }
682
683 size = _IOC_SIZE(cmd);
684
685 /* Now check variable-length commands */
686 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
687 switch (EVIOC_MASK_SIZE(cmd)) {
688
689 case EVIOCGKEY(0):
690 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
691
692 case EVIOCGLED(0):
693 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
694
695 case EVIOCGSND(0):
696 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
697
698 case EVIOCGSW(0):
699 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
700
701 case EVIOCGNAME(0):
702 return str_to_user(dev->name, size, p);
703
704 case EVIOCGPHYS(0):
705 return str_to_user(dev->phys, size, p);
706
707 case EVIOCGUNIQ(0):
708 return str_to_user(dev->uniq, size, p);
709
710 case EVIOC_MASK_SIZE(EVIOCSFF):
711 if (input_ff_effect_from_user(p, size, &effect))
712 return -EFAULT;
713
714 error = input_ff_upload(dev, &effect, file);
715
716 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
717 return -EFAULT;
718
719 return error;
720 }
721
722 /* Multi-number variable-length handlers */
723 if (_IOC_TYPE(cmd) != 'E')
724 return -EINVAL;
725
726 if (_IOC_DIR(cmd) == _IOC_READ) {
727
728 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
729 return handle_eviocgbit(dev,
730 _IOC_NR(cmd) & EV_MAX, size,
731 p, compat_mode);
732
733 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
734
735 if (!dev->absinfo)
736 return -EINVAL;
737
738 t = _IOC_NR(cmd) & ABS_MAX;
739 abs = dev->absinfo[t];
740
741 if (copy_to_user(p, &abs, min_t(size_t,
742 size, sizeof(struct input_absinfo))))
743 return -EFAULT;
744
745 return 0;
746 }
747 }
748
749 if (_IOC_DIR(cmd) == _IOC_WRITE) {
750
751 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
752
753 if (!dev->absinfo)
754 return -EINVAL;
755
756 t = _IOC_NR(cmd) & ABS_MAX;
757
758 if (copy_from_user(&abs, p, min_t(size_t,
759 size, sizeof(struct input_absinfo))))
760 return -EFAULT;
761
762 if (size < sizeof(struct input_absinfo))
763 abs.resolution = 0;
764
765 /* We can't change number of reserved MT slots */
766 if (t == ABS_MT_SLOT)
767 return -EINVAL;
768
769 /*
770 * Take event lock to ensure that we are not
771 * changing device parameters in the middle
772 * of event.
773 */
774 spin_lock_irq(&dev->event_lock);
775 dev->absinfo[t] = abs;
776 spin_unlock_irq(&dev->event_lock);
777
778 return 0;
779 }
780 }
781
782 return -EINVAL;
783 }
784
785 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
786 void __user *p, int compat_mode)
787 {
788 struct evdev_client *client = file->private_data;
789 struct evdev *evdev = client->evdev;
790 int retval;
791
792 retval = mutex_lock_interruptible(&evdev->mutex);
793 if (retval)
794 return retval;
795
796 if (!evdev->exist) {
797 retval = -ENODEV;
798 goto out;
799 }
800
801 retval = evdev_do_ioctl(file, cmd, p, compat_mode);
802
803 out:
804 mutex_unlock(&evdev->mutex);
805 return retval;
806 }
807
808 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
809 {
810 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
811 }
812
813 #ifdef CONFIG_COMPAT
814 static long evdev_ioctl_compat(struct file *file,
815 unsigned int cmd, unsigned long arg)
816 {
817 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
818 }
819 #endif
820
821 static const struct file_operations evdev_fops = {
822 .owner = THIS_MODULE,
823 .read = evdev_read,
824 .write = evdev_write,
825 .poll = evdev_poll,
826 .open = evdev_open,
827 .release = evdev_release,
828 .unlocked_ioctl = evdev_ioctl,
829 #ifdef CONFIG_COMPAT
830 .compat_ioctl = evdev_ioctl_compat,
831 #endif
832 .fasync = evdev_fasync,
833 .flush = evdev_flush,
834 .llseek = no_llseek,
835 };
836
837 static int evdev_install_chrdev(struct evdev *evdev)
838 {
839 /*
840 * No need to do any locking here as calls to connect and
841 * disconnect are serialized by the input core
842 */
843 evdev_table[evdev->minor] = evdev;
844 return 0;
845 }
846
847 static void evdev_remove_chrdev(struct evdev *evdev)
848 {
849 /*
850 * Lock evdev table to prevent race with evdev_open()
851 */
852 mutex_lock(&evdev_table_mutex);
853 evdev_table[evdev->minor] = NULL;
854 mutex_unlock(&evdev_table_mutex);
855 }
856
857 /*
858 * Mark device non-existent. This disables writes, ioctls and
859 * prevents new users from opening the device. Already posted
860 * blocking reads will stay, however new ones will fail.
861 */
862 static void evdev_mark_dead(struct evdev *evdev)
863 {
864 mutex_lock(&evdev->mutex);
865 evdev->exist = false;
866 mutex_unlock(&evdev->mutex);
867 }
868
869 static void evdev_cleanup(struct evdev *evdev)
870 {
871 struct input_handle *handle = &evdev->handle;
872
873 evdev_mark_dead(evdev);
874 evdev_hangup(evdev);
875 evdev_remove_chrdev(evdev);
876
877 /* evdev is marked dead so no one else accesses evdev->open */
878 if (evdev->open) {
879 input_flush_device(handle, NULL);
880 input_close_device(handle);
881 }
882 }
883
884 /*
885 * Create new evdev device. Note that input core serializes calls
886 * to connect and disconnect so we don't need to lock evdev_table here.
887 */
888 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
889 const struct input_device_id *id)
890 {
891 struct evdev *evdev;
892 int minor;
893 int error;
894
895 for (minor = 0; minor < EVDEV_MINORS; minor++)
896 if (!evdev_table[minor])
897 break;
898
899 if (minor == EVDEV_MINORS) {
900 printk(KERN_ERR "evdev: no more free evdev devices\n");
901 return -ENFILE;
902 }
903
904 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
905 if (!evdev)
906 return -ENOMEM;
907
908 INIT_LIST_HEAD(&evdev->client_list);
909 spin_lock_init(&evdev->client_lock);
910 mutex_init(&evdev->mutex);
911 init_waitqueue_head(&evdev->wait);
912
913 dev_set_name(&evdev->dev, "event%d", minor);
914 evdev->exist = true;
915 evdev->minor = minor;
916
917 evdev->handle.dev = input_get_device(dev);
918 evdev->handle.name = dev_name(&evdev->dev);
919 evdev->handle.handler = handler;
920 evdev->handle.private = evdev;
921
922 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
923 evdev->dev.class = &input_class;
924 evdev->dev.parent = &dev->dev;
925 evdev->dev.release = evdev_free;
926 device_initialize(&evdev->dev);
927
928 error = input_register_handle(&evdev->handle);
929 if (error)
930 goto err_free_evdev;
931
932 error = evdev_install_chrdev(evdev);
933 if (error)
934 goto err_unregister_handle;
935
936 error = device_add(&evdev->dev);
937 if (error)
938 goto err_cleanup_evdev;
939
940 return 0;
941
942 err_cleanup_evdev:
943 evdev_cleanup(evdev);
944 err_unregister_handle:
945 input_unregister_handle(&evdev->handle);
946 err_free_evdev:
947 put_device(&evdev->dev);
948 return error;
949 }
950
951 static void evdev_disconnect(struct input_handle *handle)
952 {
953 struct evdev *evdev = handle->private;
954
955 device_del(&evdev->dev);
956 evdev_cleanup(evdev);
957 input_unregister_handle(handle);
958 put_device(&evdev->dev);
959 }
960
961 static const struct input_device_id evdev_ids[] = {
962 { .driver_info = 1 }, /* Matches all devices */
963 { }, /* Terminating zero entry */
964 };
965
966 MODULE_DEVICE_TABLE(input, evdev_ids);
967
968 static struct input_handler evdev_handler = {
969 .event = evdev_event,
970 .connect = evdev_connect,
971 .disconnect = evdev_disconnect,
972 .fops = &evdev_fops,
973 .minor = EVDEV_MINOR_BASE,
974 .name = "evdev",
975 .id_table = evdev_ids,
976 };
977
978 static int __init evdev_init(void)
979 {
980 return input_register_handler(&evdev_handler);
981 }
982
983 static void __exit evdev_exit(void)
984 {
985 input_unregister_handler(&evdev_handler);
986 }
987
988 module_init(evdev_init);
989 module_exit(evdev_exit);
990
991 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
992 MODULE_DESCRIPTION("Input driver event char devices");
993 MODULE_LICENSE("GPL");
Linus' kernel tree