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 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");