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_BUFFER_SIZE       64
  14
  15 #include <linux/poll.h>
  16 #include <linux/slab.h>
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/input.h>
  20 #include <linux/major.h>
  21 #include <linux/device.h>
  22 #include <linux/compat.h>
  23
  24 struct evdev {
  25         int exist;
  26         int open;
  27         int minor;
  28         char name[16];
  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 };
  37
  38 struct evdev_client {
  39         struct input_event buffer[EVDEV_BUFFER_SIZE];
  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 };
  47
  48 static struct evdev *evdev_table[EVDEV_MINORS];
  49 static DEFINE_MUTEX(evdev_table_mutex);
  50
  51 static void evdev_pass_event(struct evdev_client *client,
  52                              struct input_event *event)
  53 {
  54         /*
  55          * Interrupts are disabled, just acquire the lock
  56          */
  57         spin_lock(&client->buffer_lock);
  58         client->buffer[client->head++] = *event;
  59         client->head &= EVDEV_BUFFER_SIZE - 1;
  60         spin_unlock(&client->buffer_lock);
  61
  62         kill_fasync(&client->fasync, SIGIO, POLL_IN);
  63 }
  64
  65 /*
  66  * Pass incoming event to all connected clients. Note that we are
  67  * caleld under a spinlock with interrupts off so we don't need
  68  * to use rcu_read_lock() here. Writers will be using syncronize_sched()
  69  * instead of synchrnoize_rcu().
  70  */
  71 static void evdev_event(struct input_handle *handle,
  72                         unsigned int type, unsigned int code, int value)
  73 {
  74         struct evdev *evdev = handle->private;
  75         struct evdev_client *client;
  76         struct input_event event;
  77
  78         do_gettimeofday(&event.time);
  79         event.type = type;
  80         event.code = code;
  81         event.value = value;
  82
  83         client = rcu_dereference(evdev->grab);
  84         if (client)
  85                 evdev_pass_event(client, &event);
  86         else
  87                 list_for_each_entry_rcu(client, &evdev->client_list, node)
  88                         evdev_pass_event(client, &event);
  89
  90         wake_up_interruptible(&evdev->wait);
  91 }
  92
  93 static int evdev_fasync(int fd, struct file *file, int on)
  94 {
  95         struct evdev_client *client = file->private_data;
  96         int retval;
  97
  98         retval = fasync_helper(fd, file, on, &client->fasync);
  99
 100         return retval < 0 ? retval : 0;
 101 }
 102
 103 static int evdev_flush(struct file *file, fl_owner_t id)
 104 {
 105         struct evdev_client *client = file->private_data;
 106         struct evdev *evdev = client->evdev;
 107         int retval;
 108
 109         retval = mutex_lock_interruptible(&evdev->mutex);
 110         if (retval)
 111                 return retval;
 112
 113         if (!evdev->exist)
 114                 retval = -ENODEV;
 115         else
 116                 retval = input_flush_device(&evdev->handle, file);
 117
 118         mutex_unlock(&evdev->mutex);
 119         return retval;
 120 }
 121
 122 static void evdev_free(struct device *dev)
 123 {
 124         struct evdev *evdev = container_of(dev, struct evdev, dev);
 125
 126         kfree(evdev);
 127 }
 128
 129 /*
 130  * Grabs an event device (along with underlying input device).
 131  * This function is called with evdev->mutex taken.
 132  */
 133 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 134 {
 135         int error;
 136
 137         if (evdev->grab)
 138                 return -EBUSY;
 139
 140         error = input_grab_device(&evdev->handle);
 141         if (error)
 142                 return error;
 143
 144         rcu_assign_pointer(evdev->grab, client);
 145         /*
 146          * We don't use synchronize_rcu() here because read-side
 147          * critical section is protected by a spinlock instead
 148          * of rcu_read_lock().
 149          */
 150         synchronize_sched();
 151
 152         return 0;
 153 }
 154
 155 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 156 {
 157         if (evdev->grab != client)
 158                 return  -EINVAL;
 159
 160         rcu_assign_pointer(evdev->grab, NULL);
 161         synchronize_sched();
 162         input_release_device(&evdev->handle);
 163
 164         return 0;
 165 }
 166
 167 static void evdev_attach_client(struct evdev *evdev,
 168                                 struct evdev_client *client)
 169 {
 170         spin_lock(&evdev->client_lock);
 171         list_add_tail_rcu(&client->node, &evdev->client_list);
 172         spin_unlock(&evdev->client_lock);
 173         synchronize_sched();
 174 }
 175
 176 static void evdev_detach_client(struct evdev *evdev,
 177                                 struct evdev_client *client)
 178 {
 179         spin_lock(&evdev->client_lock);
 180         list_del_rcu(&client->node);
 181         spin_unlock(&evdev->client_lock);
 182         synchronize_sched();
 183 }
 184
 185 static int evdev_open_device(struct evdev *evdev)
 186 {
 187         int retval;
 188
 189         retval = mutex_lock_interruptible(&evdev->mutex);
 190         if (retval)
 191                 return retval;
 192
 193         if (!evdev->exist)
 194                 retval = -ENODEV;
 195         else if (!evdev->open++) {
 196                 retval = input_open_device(&evdev->handle);
 197                 if (retval)
 198                         evdev->open--;
 199         }
 200
 201         mutex_unlock(&evdev->mutex);
 202         return retval;
 203 }
 204
 205 static void evdev_close_device(struct evdev *evdev)
 206 {
 207         mutex_lock(&evdev->mutex);
 208
 209         if (evdev->exist && !--evdev->open)
 210                 input_close_device(&evdev->handle);
 211
 212         mutex_unlock(&evdev->mutex);
 213 }
 214
 215 /*
 216  * Wake up users waiting for IO so they can disconnect from
 217  * dead device.
 218  */
 219 static void evdev_hangup(struct evdev *evdev)
 220 {
 221         struct evdev_client *client;
 222
 223         spin_lock(&evdev->client_lock);
 224         list_for_each_entry(client, &evdev->client_list, node)
 225                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 226         spin_unlock(&evdev->client_lock);
 227
 228         wake_up_interruptible(&evdev->wait);
 229 }
 230
 231 static int evdev_release(struct inode *inode, struct file *file)
 232 {
 233         struct evdev_client *client = file->private_data;
 234         struct evdev *evdev = client->evdev;
 235
 236         mutex_lock(&evdev->mutex);
 237         if (evdev->grab == client)
 238                 evdev_ungrab(evdev, client);
 239         mutex_unlock(&evdev->mutex);
 240
 241         evdev_fasync(-1, file, 0);
 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 int evdev_open(struct inode *inode, struct file *file)
 252 {
 253         struct evdev *evdev;
 254         struct evdev_client *client;
 255         int i = iminor(inode) - EVDEV_MINOR_BASE;
 256         int error;
 257
 258         if (i >= EVDEV_MINORS)
 259                 return -ENODEV;
 260
 261         error = mutex_lock_interruptible(&evdev_table_mutex);
 262         if (error)
 263                 return error;
 264         evdev = evdev_table[i];
 265         if (evdev)
 266                 get_device(&evdev->dev);
 267         mutex_unlock(&evdev_table_mutex);
 268
 269         if (!evdev)
 270                 return -ENODEV;
 271
 272         client = kzalloc(sizeof(struct evdev_client), GFP_KERNEL);
 273         if (!client) {
 274                 error = -ENOMEM;
 275                 goto err_put_evdev;
 276         }
 277
 278         spin_lock_init(&client->buffer_lock);
 279         client->evdev = evdev;
 280         evdev_attach_client(evdev, client);
 281
 282         error = evdev_open_device(evdev);
 283         if (error)
 284                 goto err_free_client;
 285
 286         file->private_data = client;
 287         return 0;
 288
 289  err_free_client:
 290         evdev_detach_client(evdev, client);
 291         kfree(client);
 292  err_put_evdev:
 293         put_device(&evdev->dev);
 294         return error;
 295 }
 296
 297 #ifdef CONFIG_COMPAT
 298
 299 struct input_event_compat {
 300         struct compat_timeval time;
 301         __u16 type;
 302         __u16 code;
 303         __s32 value;
 304 };
 305
 306 /* Note to the author of this code: did it ever occur to
 307    you why the ifdefs are needed? Think about it again. -AK */
 308 #ifdef CONFIG_X86_64
 309 #  define COMPAT_TEST is_compat_task()
 310 #elif defined(CONFIG_IA64)
 311 #  define COMPAT_TEST IS_IA32_PROCESS(task_pt_regs(current))
 312 #elif defined(CONFIG_S390)
 313 #  define COMPAT_TEST test_thread_flag(TIF_31BIT)
 314 #elif defined(CONFIG_MIPS)
 315 #  define COMPAT_TEST test_thread_flag(TIF_32BIT_ADDR)
 316 #else
 317 #  define COMPAT_TEST test_thread_flag(TIF_32BIT)
 318 #endif
 319
 320 static inline size_t evdev_event_size(void)
 321 {
 322         return COMPAT_TEST ?
 323                 sizeof(struct input_event_compat) : sizeof(struct input_event);
 324 }
 325
 326 static int evdev_event_from_user(const char __user *buffer,
 327                                  struct input_event *event)
 328 {
 329         if (COMPAT_TEST) {
 330                 struct input_event_compat compat_event;
 331
 332                 if (copy_from_user(&compat_event, buffer,
 333                                    sizeof(struct input_event_compat)))
 334                         return -EFAULT;
 335
 336                 event->time.tv_sec = compat_event.time.tv_sec;
 337                 event->time.tv_usec = compat_event.time.tv_usec;
 338                 event->type = compat_event.type;
 339                 event->code = compat_event.code;
 340                 event->value = compat_event.value;
 341
 342         } else {
 343                 if (copy_from_user(event, buffer, sizeof(struct input_event)))
 344                         return -EFAULT;
 345         }
 346
 347         return 0;
 348 }
 349
 350 static int evdev_event_to_user(char __user *buffer,
 351                                 const struct input_event *event)
 352 {
 353         if (COMPAT_TEST) {
 354                 struct input_event_compat compat_event;
 355
 356                 compat_event.time.tv_sec = event->time.tv_sec;
 357                 compat_event.time.tv_usec = event->time.tv_usec;
 358                 compat_event.type = event->type;
 359                 compat_event.code = event->code;
 360                 compat_event.value = event->value;
 361
 362                 if (copy_to_user(buffer, &compat_event,
 363                                  sizeof(struct input_event_compat)))
 364                         return -EFAULT;
 365
 366         } else {
 367                 if (copy_to_user(buffer, event, sizeof(struct input_event)))
 368                         return -EFAULT;
 369         }
 370
 371         return 0;
 372 }
 373
 374 #else
 375
 376 static inline size_t evdev_event_size(void)
 377 {
 378         return sizeof(struct input_event);
 379 }
 380
 381 static int evdev_event_from_user(const char __user *buffer,
 382                                  struct input_event *event)
 383 {
 384         if (copy_from_user(event, buffer, sizeof(struct input_event)))
 385                 return -EFAULT;
 386
 387         return 0;
 388 }
 389
 390 static int evdev_event_to_user(char __user *buffer,
 391                                 const struct input_event *event)
 392 {
 393         if (copy_to_user(buffer, event, sizeof(struct input_event)))
 394                 return -EFAULT;
 395
 396         return 0;
 397 }
 398
 399 #endif /* CONFIG_COMPAT */
 400
 401 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 402                            size_t count, loff_t *ppos)
 403 {
 404         struct evdev_client *client = file->private_data;
 405         struct evdev *evdev = client->evdev;
 406         struct input_event event;
 407         int retval;
 408
 409         retval = mutex_lock_interruptible(&evdev->mutex);
 410         if (retval)
 411                 return retval;
 412
 413         if (!evdev->exist) {
 414                 retval = -ENODEV;
 415                 goto out;
 416         }
 417
 418         while (retval < count) {
 419
 420                 if (evdev_event_from_user(buffer + retval, &event)) {
 421                         retval = -EFAULT;
 422                         goto out;
 423                 }
 424
 425                 input_inject_event(&evdev->handle,
 426                                    event.type, event.code, event.value);
 427                 retval += evdev_event_size();
 428         }
 429
 430  out:
 431         mutex_unlock(&evdev->mutex);
 432         return retval;
 433 }
 434
 435 static int evdev_fetch_next_event(struct evdev_client *client,
 436                                   struct input_event *event)
 437 {
 438         int have_event;
 439
 440         spin_lock_irq(&client->buffer_lock);
 441
 442         have_event = client->head != client->tail;
 443         if (have_event) {
 444                 *event = client->buffer[client->tail++];
 445                 client->tail &= EVDEV_BUFFER_SIZE - 1;
 446         }
 447
 448         spin_unlock_irq(&client->buffer_lock);
 449
 450         return have_event;
 451 }
 452
 453 static ssize_t evdev_read(struct file *file, char __user *buffer,
 454                           size_t count, loff_t *ppos)
 455 {
 456         struct evdev_client *client = file->private_data;
 457         struct evdev *evdev = client->evdev;
 458         struct input_event event;
 459         int retval;
 460
 461         if (count < evdev_event_size())
 462                 return -EINVAL;
 463
 464         if (client->head == client->tail && evdev->exist &&
 465             (file->f_flags & O_NONBLOCK))
 466                 return -EAGAIN;
 467
 468         retval = wait_event_interruptible(evdev->wait,
 469                 client->head != client->tail || !evdev->exist);
 470         if (retval)
 471                 return retval;
 472
 473         if (!evdev->exist)
 474                 return -ENODEV;
 475
 476         while (retval + evdev_event_size() <= count &&
 477                evdev_fetch_next_event(client, &event)) {
 478
 479                 if (evdev_event_to_user(buffer + retval, &event))
 480                         return -EFAULT;
 481
 482                 retval += evdev_event_size();
 483         }
 484
 485         return retval;
 486 }
 487
 488 /* No kernel lock - fine */
 489 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 490 {
 491         struct evdev_client *client = file->private_data;
 492         struct evdev *evdev = client->evdev;
 493
 494         poll_wait(file, &evdev->wait, wait);
 495         return ((client->head == client->tail) ? 0 : (POLLIN | POLLRDNORM)) |
 496                 (evdev->exist ? 0 : (POLLHUP | POLLERR));
 497 }
 498
 499 #ifdef CONFIG_COMPAT
 500
 501 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 502 #define NBITS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 503
 504 #ifdef __BIG_ENDIAN
 505 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 506                         unsigned int maxlen, void __user *p, int compat)
 507 {
 508         int len, i;
 509
 510         if (compat) {
 511                 len = NBITS_COMPAT(maxbit) * sizeof(compat_long_t);
 512                 if (len > maxlen)
 513                         len = maxlen;
 514
 515                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 516                         if (copy_to_user((compat_long_t __user *) p + i,
 517                                          (compat_long_t *) bits +
 518                                                 i + 1 - ((i % 2) << 1),
 519                                          sizeof(compat_long_t)))
 520                                 return -EFAULT;
 521         } else {
 522                 len = NBITS(maxbit) * sizeof(long);
 523                 if (len > maxlen)
 524                         len = maxlen;
 525
 526                 if (copy_to_user(p, bits, len))
 527                         return -EFAULT;
 528         }
 529
 530         return len;
 531 }
 532 #else
 533 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 534                         unsigned int maxlen, void __user *p, int compat)
 535 {
 536         int len = compat ?
 537                         NBITS_COMPAT(maxbit) * sizeof(compat_long_t) :
 538                         NBITS(maxbit) * sizeof(long);
 539
 540         if (len > maxlen)
 541                 len = maxlen;
 542
 543         return copy_to_user(p, bits, len) ? -EFAULT : len;
 544 }
 545 #endif /* __BIG_ENDIAN */
 546
 547 #else
 548
 549 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 550                         unsigned int maxlen, void __user *p, int compat)
 551 {
 552         int len = NBITS(maxbit) * sizeof(long);
 553
 554         if (len > maxlen)
 555                 len = maxlen;
 556
 557         return copy_to_user(p, bits, len) ? -EFAULT : len;
 558 }
 559
 560 #endif /* CONFIG_COMPAT */
 561
 562 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 563 {
 564         int len;
 565
 566         if (!str)
 567                 return -ENOENT;
 568
 569         len = strlen(str) + 1;
 570         if (len > maxlen)
 571                 len = maxlen;
 572
 573         return copy_to_user(p, str, len) ? -EFAULT : len;
 574 }
 575
 576 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 577                            void __user *p, int compat_mode)
 578 {
 579         struct evdev_client *client = file->private_data;
 580         struct evdev *evdev = client->evdev;
 581         struct input_dev *dev = evdev->handle.dev;
 582         struct input_absinfo abs;
 583         struct ff_effect effect;
 584         int __user *ip = (int __user *)p;
 585         int i, t, u, v;
 586         int error;
 587
 588         switch (cmd) {
 589
 590         case EVIOCGVERSION:
 591                 return put_user(EV_VERSION, ip);
 592
 593         case EVIOCGID:
 594                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 595                         return -EFAULT;
 596                 return 0;
 597
 598         case EVIOCGREP:
 599                 if (!test_bit(EV_REP, dev->evbit))
 600                         return -ENOSYS;
 601                 if (put_user(dev->rep[REP_DELAY], ip))
 602                         return -EFAULT;
 603                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 604                         return -EFAULT;
 605                 return 0;
 606
 607         case EVIOCSREP:
 608                 if (!test_bit(EV_REP, dev->evbit))
 609                         return -ENOSYS;
 610                 if (get_user(u, ip))
 611                         return -EFAULT;
 612                 if (get_user(v, ip + 1))
 613                         return -EFAULT;
 614
 615                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 616                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 617
 618                 return 0;
 619
 620         case EVIOCGKEYCODE:
 621                 if (get_user(t, ip))
 622                         return -EFAULT;
 623
 624                 error = dev->getkeycode(dev, t, &v);
 625                 if (error)
 626                         return error;
 627
 628                 if (put_user(v, ip + 1))
 629                         return -EFAULT;
 630
 631                 return 0;
 632
 633         case EVIOCSKEYCODE:
 634                 if (get_user(t, ip) || get_user(v, ip + 1))
 635                         return -EFAULT;
 636
 637                 return dev->setkeycode(dev, t, v);
 638
 639         case EVIOCSFF:
 640                 if (copy_from_user(&effect, p, sizeof(effect)))
 641                         return -EFAULT;
 642
 643                 error = input_ff_upload(dev, &effect, file);
 644
 645                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 646                         return -EFAULT;
 647
 648                 return error;
 649
 650         case EVIOCRMFF:
 651                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 652
 653         case EVIOCGEFFECTS:
 654                 i = test_bit(EV_FF, dev->evbit) ?
 655                                 dev->ff->max_effects : 0;
 656                 if (put_user(i, ip))
 657                         return -EFAULT;
 658                 return 0;
 659
 660         case EVIOCGRAB:
 661                 if (p)
 662                         return evdev_grab(evdev, client);
 663                 else
 664                         return evdev_ungrab(evdev, client);
 665
 666         default:
 667
 668                 if (_IOC_TYPE(cmd) != 'E')
 669                         return -EINVAL;
 670
 671                 if (_IOC_DIR(cmd) == _IOC_READ) {
 672
 673                         if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) {
 674
 675                                 unsigned long *bits;
 676                                 int len;
 677
 678                                 switch (_IOC_NR(cmd) & EV_MAX) {
 679
 680                                 case      0: bits = dev->evbit;  len = EV_MAX;  break;
 681                                 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 682                                 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 683                                 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 684                                 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 685                                 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 686                                 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 687                                 case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 688                                 case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 689                                 default: return -EINVAL;
 690                         }
 691                                 return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
 692                         }
 693
 694                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))
 695                                 return bits_to_user(dev->key, KEY_MAX, _IOC_SIZE(cmd),
 696                                                     p, compat_mode);
 697
 698                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGLED(0)))
 699                                 return bits_to_user(dev->led, LED_MAX, _IOC_SIZE(cmd),
 700                                                     p, compat_mode);
 701
 702                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSND(0)))
 703                                 return bits_to_user(dev->snd, SND_MAX, _IOC_SIZE(cmd),
 704                                                     p, compat_mode);
 705
 706                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSW(0)))
 707                                 return bits_to_user(dev->sw, SW_MAX, _IOC_SIZE(cmd),
 708                                                     p, compat_mode);
 709
 710                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGNAME(0)))
 711                                 return str_to_user(dev->name, _IOC_SIZE(cmd), p);
 712
 713                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGPHYS(0)))
 714                                 return str_to_user(dev->phys, _IOC_SIZE(cmd), p);
 715
 716                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGUNIQ(0)))
 717                                 return str_to_user(dev->uniq, _IOC_SIZE(cmd), p);
 718
 719                         if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 720
 721                                 t = _IOC_NR(cmd) & ABS_MAX;
 722
 723                                 abs.value = dev->abs[t];
 724                                 abs.minimum = dev->absmin[t];
 725                                 abs.maximum = dev->absmax[t];
 726                                 abs.fuzz = dev->absfuzz[t];
 727                                 abs.flat = dev->absflat[t];
 728
 729                                 if (copy_to_user(p, &abs, sizeof(struct input_absinfo)))
 730                                         return -EFAULT;
 731
 732                                 return 0;
 733                         }
 734
 735                 }
 736
 737                 if (_IOC_DIR(cmd) == _IOC_WRITE) {
 738
 739                         if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 740
 741                                 t = _IOC_NR(cmd) & ABS_MAX;
 742
 743                                 if (copy_from_user(&abs, p,
 744                                                 sizeof(struct input_absinfo)))
 745                                         return -EFAULT;
 746
 747                                 /*
 748                                  * Take event lock to ensure that we are not
 749                                  * changing device parameters in the middle
 750                                  * of event.
 751                                  */
 752                                 spin_lock_irq(&dev->event_lock);
 753
 754                                 dev->abs[t] = abs.value;
 755                                 dev->absmin[t] = abs.minimum;
 756                                 dev->absmax[t] = abs.maximum;
 757                                 dev->absfuzz[t] = abs.fuzz;
 758                                 dev->absflat[t] = abs.flat;
 759
 760                                 spin_unlock_irq(&dev->event_lock);
 761
 762                                 return 0;
 763                         }
 764                 }
 765         }
 766         return -EINVAL;
 767 }
 768
 769 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 770                                 void __user *p, int compat_mode)
 771 {
 772         struct evdev_client *client = file->private_data;
 773         struct evdev *evdev = client->evdev;
 774         int retval;
 775
 776         retval = mutex_lock_interruptible(&evdev->mutex);
 777         if (retval)
 778                 return retval;
 779
 780         if (!evdev->exist) {
 781                 retval = -ENODEV;
 782                 goto out;
 783         }
 784
 785         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
 786
 787  out:
 788         mutex_unlock(&evdev->mutex);
 789         return retval;
 790 }
 791
 792 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 793 {
 794         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
 795 }
 796
 797 #ifdef CONFIG_COMPAT
 798 static long evdev_ioctl_compat(struct file *file,
 799                                 unsigned int cmd, unsigned long arg)
 800 {
 801         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
 802 }
 803 #endif
 804
 805 static const struct file_operations evdev_fops = {
 806         .owner          = THIS_MODULE,
 807         .read           = evdev_read,
 808         .write          = evdev_write,
 809         .poll           = evdev_poll,
 810         .open           = evdev_open,
 811         .release        = evdev_release,
 812         .unlocked_ioctl = evdev_ioctl,
 813 #ifdef CONFIG_COMPAT
 814         .compat_ioctl   = evdev_ioctl_compat,
 815 #endif
 816         .fasync         = evdev_fasync,
 817         .flush          = evdev_flush
 818 };
 819
 820 static int evdev_install_chrdev(struct evdev *evdev)
 821 {
 822         /*
 823          * No need to do any locking here as calls to connect and
 824          * disconnect are serialized by the input core
 825          */
 826         evdev_table[evdev->minor] = evdev;
 827         return 0;
 828 }
 829
 830 static void evdev_remove_chrdev(struct evdev *evdev)
 831 {
 832         /*
 833          * Lock evdev table to prevent race with evdev_open()
 834          */
 835         mutex_lock(&evdev_table_mutex);
 836         evdev_table[evdev->minor] = NULL;
 837         mutex_unlock(&evdev_table_mutex);
 838 }
 839
 840 /*
 841  * Mark device non-existent. This disables writes, ioctls and
 842  * prevents new users from opening the device. Already posted
 843  * blocking reads will stay, however new ones will fail.
 844  */
 845 static void evdev_mark_dead(struct evdev *evdev)
 846 {
 847         mutex_lock(&evdev->mutex);
 848         evdev->exist = 0;
 849         mutex_unlock(&evdev->mutex);
 850 }
 851
 852 static void evdev_cleanup(struct evdev *evdev)
 853 {
 854         struct input_handle *handle = &evdev->handle;
 855
 856         evdev_mark_dead(evdev);
 857         evdev_hangup(evdev);
 858         evdev_remove_chrdev(evdev);
 859
 860         /* evdev is marked dead so no one else accesses evdev->open */
 861         if (evdev->open) {
 862                 input_flush_device(handle, NULL);
 863                 input_close_device(handle);
 864         }
 865 }
 866
 867 /*
 868  * Create new evdev device. Note that input core serializes calls
 869  * to connect and disconnect so we don't need to lock evdev_table here.
 870  */
 871 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
 872                          const struct input_device_id *id)
 873 {
 874         struct evdev *evdev;
 875         int minor;
 876         int error;
 877
 878         for (minor = 0; minor < EVDEV_MINORS; minor++)
 879                 if (!evdev_table[minor])
 880                         break;
 881
 882         if (minor == EVDEV_MINORS) {
 883                 printk(KERN_ERR "evdev: no more free evdev devices\n");
 884                 return -ENFILE;
 885         }
 886
 887         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
 888         if (!evdev)
 889                 return -ENOMEM;
 890
 891         INIT_LIST_HEAD(&evdev->client_list);
 892         spin_lock_init(&evdev->client_lock);
 893         mutex_init(&evdev->mutex);
 894         init_waitqueue_head(&evdev->wait);
 895
 896         snprintf(evdev->name, sizeof(evdev->name), "event%d", minor);
 897         evdev->exist = 1;
 898         evdev->minor = minor;
 899
 900         evdev->handle.dev = dev;
 901         evdev->handle.name = evdev->name;
 902         evdev->handle.handler = handler;
 903         evdev->handle.private = evdev;
 904
 905         strlcpy(evdev->dev.bus_id, evdev->name, sizeof(evdev->dev.bus_id));
 906         evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 907         evdev->dev.class = &input_class;
 908         evdev->dev.parent = &dev->dev;
 909         evdev->dev.release = evdev_free;
 910         device_initialize(&evdev->dev);
 911
 912         error = input_register_handle(&evdev->handle);
 913         if (error)
 914                 goto err_free_evdev;
 915
 916         error = evdev_install_chrdev(evdev);
 917         if (error)
 918                 goto err_unregister_handle;
 919
 920         error = device_add(&evdev->dev);
 921         if (error)
 922                 goto err_cleanup_evdev;
 923
 924         return 0;
 925
 926  err_cleanup_evdev:
 927         evdev_cleanup(evdev);
 928  err_unregister_handle:
 929         input_unregister_handle(&evdev->handle);
 930  err_free_evdev:
 931         put_device(&evdev->dev);
 932         return error;
 933 }
 934
 935 static void evdev_disconnect(struct input_handle *handle)
 936 {
 937         struct evdev *evdev = handle->private;
 938
 939         device_del(&evdev->dev);
 940         evdev_cleanup(evdev);
 941         input_unregister_handle(handle);
 942         put_device(&evdev->dev);
 943 }
 944
 945 static const struct input_device_id evdev_ids[] = {
 946         { .driver_info = 1 },   /* Matches all devices */
 947         { },                    /* Terminating zero entry */
 948 };
 949
 950 MODULE_DEVICE_TABLE(input, evdev_ids);
 951
 952 static struct input_handler evdev_handler = {
 953         .event          = evdev_event,
 954         .connect        = evdev_connect,
 955         .disconnect     = evdev_disconnect,
 956         .fops           = &evdev_fops,
 957         .minor          = EVDEV_MINOR_BASE,
 958         .name           = "evdev",
 959         .id_table       = evdev_ids,
 960 };
 961
 962 static int __init evdev_init(void)
 963 {
 964         return input_register_handler(&evdev_handler);
 965 }
 966
 967 static void __exit evdev_exit(void)
 968 {
 969         input_unregister_handler(&evdev_handler);
 970 }
 971
 972 module_init(evdev_init);
 973 module_exit(evdev_exit);
 974
 975 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
 976 MODULE_DESCRIPTION("Input driver event char devices");
 977 MODULE_LICENSE("GPL");