Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl
[linux-2.6.git] / drivers / input / evdev.c
1 /*
2  * Event char devices, giving access to raw input device events.
3  *
4  * Copyright (c) 1999-2002 Vojtech Pavlik
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License version 2 as published by
8  * the Free Software Foundation.
9  */
10
11 #define 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 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
722 static 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
745 static 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
751 static 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
758 static 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         .llseek         = no_llseek,
772 };
773
774 static int evdev_install_chrdev(struct evdev *evdev)
775 {
776         /*
777          * No need to do any locking here as calls to connect and
778          * disconnect are serialized by the input core
779          */
780         evdev_table[evdev->minor] = evdev;
781         return 0;
782 }
783
784 static void evdev_remove_chrdev(struct evdev *evdev)
785 {
786         /*
787          * Lock evdev table to prevent race with evdev_open()
788          */
789         mutex_lock(&evdev_table_mutex);
790         evdev_table[evdev->minor] = NULL;
791         mutex_unlock(&evdev_table_mutex);
792 }
793
794 /*
795  * Mark device non-existent. This disables writes, ioctls and
796  * prevents new users from opening the device. Already posted
797  * blocking reads will stay, however new ones will fail.
798  */
799 static void evdev_mark_dead(struct evdev *evdev)
800 {
801         mutex_lock(&evdev->mutex);
802         evdev->exist = false;
803         mutex_unlock(&evdev->mutex);
804 }
805
806 static void evdev_cleanup(struct evdev *evdev)
807 {
808         struct input_handle *handle = &evdev->handle;
809
810         evdev_mark_dead(evdev);
811         evdev_hangup(evdev);
812         evdev_remove_chrdev(evdev);
813
814         /* evdev is marked dead so no one else accesses evdev->open */
815         if (evdev->open) {
816                 input_flush_device(handle, NULL);
817                 input_close_device(handle);
818         }
819 }
820
821 /*
822  * Create new evdev device. Note that input core serializes calls
823  * to connect and disconnect so we don't need to lock evdev_table here.
824  */
825 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
826                          const struct input_device_id *id)
827 {
828         struct evdev *evdev;
829         int minor;
830         int error;
831
832         for (minor = 0; minor < EVDEV_MINORS; minor++)
833                 if (!evdev_table[minor])
834                         break;
835
836         if (minor == EVDEV_MINORS) {
837                 printk(KERN_ERR "evdev: no more free evdev devices\n");
838                 return -ENFILE;
839         }
840
841         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
842         if (!evdev)
843                 return -ENOMEM;
844
845         INIT_LIST_HEAD(&evdev->client_list);
846         spin_lock_init(&evdev->client_lock);
847         mutex_init(&evdev->mutex);
848         init_waitqueue_head(&evdev->wait);
849
850         dev_set_name(&evdev->dev, "event%d", minor);
851         evdev->exist = true;
852         evdev->minor = minor;
853
854         evdev->handle.dev = input_get_device(dev);
855         evdev->handle.name = dev_name(&evdev->dev);
856         evdev->handle.handler = handler;
857         evdev->handle.private = evdev;
858
859         evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
860         evdev->dev.class = &input_class;
861         evdev->dev.parent = &dev->dev;
862         evdev->dev.release = evdev_free;
863         device_initialize(&evdev->dev);
864
865         error = input_register_handle(&evdev->handle);
866         if (error)
867                 goto err_free_evdev;
868
869         error = evdev_install_chrdev(evdev);
870         if (error)
871                 goto err_unregister_handle;
872
873         error = device_add(&evdev->dev);
874         if (error)
875                 goto err_cleanup_evdev;
876
877         return 0;
878
879  err_cleanup_evdev:
880         evdev_cleanup(evdev);
881  err_unregister_handle:
882         input_unregister_handle(&evdev->handle);
883  err_free_evdev:
884         put_device(&evdev->dev);
885         return error;
886 }
887
888 static void evdev_disconnect(struct input_handle *handle)
889 {
890         struct evdev *evdev = handle->private;
891
892         device_del(&evdev->dev);
893         evdev_cleanup(evdev);
894         input_unregister_handle(handle);
895         put_device(&evdev->dev);
896 }
897
898 static const struct input_device_id evdev_ids[] = {
899         { .driver_info = 1 },   /* Matches all devices */
900         { },                    /* Terminating zero entry */
901 };
902
903 MODULE_DEVICE_TABLE(input, evdev_ids);
904
905 static struct input_handler evdev_handler = {
906         .event          = evdev_event,
907         .connect        = evdev_connect,
908         .disconnect     = evdev_disconnect,
909         .fops           = &evdev_fops,
910         .minor          = EVDEV_MINOR_BASE,
911         .name           = "evdev",
912         .id_table       = evdev_ids,
913 };
914
915 static int __init evdev_init(void)
916 {
917         return input_register_handler(&evdev_handler);
918 }
919
920 static void __exit evdev_exit(void)
921 {
922         input_unregister_handler(&evdev_handler);
923 }
924
925 module_init(evdev_init);
926 module_exit(evdev_exit);
927
928 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
929 MODULE_DESCRIPTION("Input driver event char devices");
930 MODULE_LICENSE("GPL");