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 pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #define EVDEV_MINOR_BASE        64
  14 #define EVDEV_MINORS            32
  15 #define EVDEV_MIN_BUFFER_SIZE   64U
  16 #define EVDEV_BUF_PACKETS       8
  17
  18 #include <linux/poll.h>
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/input.h>
  24 #include <linux/major.h>
  25 #include <linux/device.h>
  26 #include "input-compat.h"
  27
  28 struct evdev {
  29         int open;
  30         int minor;
  31         struct input_handle handle;
  32         wait_queue_head_t wait;
  33         struct evdev_client __rcu *grab;
  34         struct list_head client_list;
  35         spinlock_t client_lock; /* protects client_list */
  36         struct mutex mutex;
  37         struct device dev;
  38         bool exist;
  39 };
  40
  41 struct evdev_client {
  42         int head;
  43         int tail;
  44         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  45         struct fasync_struct *fasync;
  46         struct evdev *evdev;
  47         struct list_head node;
  48         int bufsize;
  49         struct input_event buffer[];
  50 };
  51
  52 static struct evdev *evdev_table[EVDEV_MINORS];
  53 static DEFINE_MUTEX(evdev_table_mutex);
  54
  55 static void evdev_pass_event(struct evdev_client *client,
  56                              struct input_event *event)
  57 {
  58         /*
  59          * Interrupts are disabled, just acquire the lock.
  60          * Make sure we don't leave with the client buffer
  61          * "empty" by having client->head == client->tail.
  62          */
  63         spin_lock(&client->buffer_lock);
  64         do {
  65                 client->buffer[client->head++] = *event;
  66                 client->head &= client->bufsize - 1;
  67         } while (client->head == client->tail);
  68         spin_unlock(&client->buffer_lock);
  69
  70         if (event->type == EV_SYN)
  71                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
  72 }
  73
  74 /*
  75  * Pass incoming event to all connected clients.
  76  */
  77 static void evdev_event(struct input_handle *handle,
  78                         unsigned int type, unsigned int code, int value)
  79 {
  80         struct evdev *evdev = handle->private;
  81         struct evdev_client *client;
  82         struct input_event event;
  83
  84         do_gettimeofday(&event.time);
  85         event.type = type;
  86         event.code = code;
  87         event.value = value;
  88
  89         rcu_read_lock();
  90
  91         client = rcu_dereference(evdev->grab);
  92         if (client)
  93                 evdev_pass_event(client, &event);
  94         else
  95                 list_for_each_entry_rcu(client, &evdev->client_list, node)
  96                         evdev_pass_event(client, &event);
  97
  98         rcu_read_unlock();
  99
 100         wake_up_interruptible(&evdev->wait);
 101 }
 102
 103 static int evdev_fasync(int fd, struct file *file, int on)
 104 {
 105         struct evdev_client *client = file->private_data;
 106
 107         return fasync_helper(fd, file, on, &client->fasync);
 108 }
 109
 110 static int evdev_flush(struct file *file, fl_owner_t id)
 111 {
 112         struct evdev_client *client = file->private_data;
 113         struct evdev *evdev = client->evdev;
 114         int retval;
 115
 116         retval = mutex_lock_interruptible(&evdev->mutex);
 117         if (retval)
 118                 return retval;
 119
 120         if (!evdev->exist)
 121                 retval = -ENODEV;
 122         else
 123                 retval = input_flush_device(&evdev->handle, file);
 124
 125         mutex_unlock(&evdev->mutex);
 126         return retval;
 127 }
 128
 129 static void evdev_free(struct device *dev)
 130 {
 131         struct evdev *evdev = container_of(dev, struct evdev, dev);
 132
 133         input_put_device(evdev->handle.dev);
 134         kfree(evdev);
 135 }
 136
 137 /*
 138  * Grabs an event device (along with underlying input device).
 139  * This function is called with evdev->mutex taken.
 140  */
 141 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 142 {
 143         int error;
 144
 145         if (evdev->grab)
 146                 return -EBUSY;
 147
 148         error = input_grab_device(&evdev->handle);
 149         if (error)
 150                 return error;
 151
 152         rcu_assign_pointer(evdev->grab, client);
 153         synchronize_rcu();
 154
 155         return 0;
 156 }
 157
 158 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 159 {
 160         if (evdev->grab != client)
 161                 return  -EINVAL;
 162
 163         rcu_assign_pointer(evdev->grab, NULL);
 164         synchronize_rcu();
 165         input_release_device(&evdev->handle);
 166
 167         return 0;
 168 }
 169
 170 static void evdev_attach_client(struct evdev *evdev,
 171                                 struct evdev_client *client)
 172 {
 173         spin_lock(&evdev->client_lock);
 174         list_add_tail_rcu(&client->node, &evdev->client_list);
 175         spin_unlock(&evdev->client_lock);
 176         synchronize_rcu();
 177 }
 178
 179 static void evdev_detach_client(struct evdev *evdev,
 180                                 struct evdev_client *client)
 181 {
 182         spin_lock(&evdev->client_lock);
 183         list_del_rcu(&client->node);
 184         spin_unlock(&evdev->client_lock);
 185         synchronize_rcu();
 186 }
 187
 188 static int evdev_open_device(struct evdev *evdev)
 189 {
 190         int retval;
 191
 192         retval = mutex_lock_interruptible(&evdev->mutex);
 193         if (retval)
 194                 return retval;
 195
 196         if (!evdev->exist)
 197                 retval = -ENODEV;
 198         else if (!evdev->open++) {
 199                 retval = input_open_device(&evdev->handle);
 200                 if (retval)
 201                         evdev->open--;
 202         }
 203
 204         mutex_unlock(&evdev->mutex);
 205         return retval;
 206 }
 207
 208 static void evdev_close_device(struct evdev *evdev)
 209 {
 210         mutex_lock(&evdev->mutex);
 211
 212         if (evdev->exist && !--evdev->open)
 213                 input_close_device(&evdev->handle);
 214
 215         mutex_unlock(&evdev->mutex);
 216 }
 217
 218 /*
 219  * Wake up users waiting for IO so they can disconnect from
 220  * dead device.
 221  */
 222 static void evdev_hangup(struct evdev *evdev)
 223 {
 224         struct evdev_client *client;
 225
 226         spin_lock(&evdev->client_lock);
 227         list_for_each_entry(client, &evdev->client_list, node)
 228                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 229         spin_unlock(&evdev->client_lock);
 230
 231         wake_up_interruptible(&evdev->wait);
 232 }
 233
 234 static int evdev_release(struct inode *inode, struct file *file)
 235 {
 236         struct evdev_client *client = file->private_data;
 237         struct evdev *evdev = client->evdev;
 238
 239         mutex_lock(&evdev->mutex);
 240         if (evdev->grab == client)
 241                 evdev_ungrab(evdev, client);
 242         mutex_unlock(&evdev->mutex);
 243
 244         evdev_detach_client(evdev, client);
 245         kfree(client);
 246
 247         evdev_close_device(evdev);
 248         put_device(&evdev->dev);
 249
 250         return 0;
 251 }
 252
 253 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 254 {
 255         unsigned int n_events =
 256                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 257                     EVDEV_MIN_BUFFER_SIZE);
 258
 259         return roundup_pow_of_two(n_events);
 260 }
 261
 262 static int evdev_open(struct inode *inode, struct file *file)
 263 {
 264         struct evdev *evdev;
 265         struct evdev_client *client;
 266         int i = iminor(inode) - EVDEV_MINOR_BASE;
 267         unsigned int bufsize;
 268         int error;
 269
 270         if (i >= EVDEV_MINORS)
 271                 return -ENODEV;
 272
 273         error = mutex_lock_interruptible(&evdev_table_mutex);
 274         if (error)
 275                 return error;
 276         evdev = evdev_table[i];
 277         if (evdev)
 278                 get_device(&evdev->dev);
 279         mutex_unlock(&evdev_table_mutex);
 280
 281         if (!evdev)
 282                 return -ENODEV;
 283
 284         bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 285
 286         client = kzalloc(sizeof(struct evdev_client) +
 287                                 bufsize * sizeof(struct input_event),
 288                          GFP_KERNEL);
 289         if (!client) {
 290                 error = -ENOMEM;
 291                 goto err_put_evdev;
 292         }
 293
 294         client->bufsize = bufsize;
 295         spin_lock_init(&client->buffer_lock);
 296         client->evdev = evdev;
 297         evdev_attach_client(evdev, client);
 298
 299         error = evdev_open_device(evdev);
 300         if (error)
 301                 goto err_free_client;
 302
 303         file->private_data = client;
 304         nonseekable_open(inode, file);
 305
 306         return 0;
 307
 308  err_free_client:
 309         evdev_detach_client(evdev, client);
 310         kfree(client);
 311  err_put_evdev:
 312         put_device(&evdev->dev);
 313         return error;
 314 }
 315
 316 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 317                            size_t count, loff_t *ppos)
 318 {
 319         struct evdev_client *client = file->private_data;
 320         struct evdev *evdev = client->evdev;
 321         struct input_event event;
 322         int retval;
 323
 324         if (count < input_event_size())
 325                 return -EINVAL;
 326
 327         retval = mutex_lock_interruptible(&evdev->mutex);
 328         if (retval)
 329                 return retval;
 330
 331         if (!evdev->exist) {
 332                 retval = -ENODEV;
 333                 goto out;
 334         }
 335
 336         do {
 337                 if (input_event_from_user(buffer + retval, &event)) {
 338                         retval = -EFAULT;
 339                         goto out;
 340                 }
 341                 retval += input_event_size();
 342
 343                 input_inject_event(&evdev->handle,
 344                                    event.type, event.code, event.value);
 345         } while (retval + input_event_size() <= count);
 346
 347  out:
 348         mutex_unlock(&evdev->mutex);
 349         return retval;
 350 }
 351
 352 static int evdev_fetch_next_event(struct evdev_client *client,
 353                                   struct input_event *event)
 354 {
 355         int have_event;
 356
 357         spin_lock_irq(&client->buffer_lock);
 358
 359         have_event = client->head != client->tail;
 360         if (have_event) {
 361                 *event = client->buffer[client->tail++];
 362                 client->tail &= client->bufsize - 1;
 363         }
 364
 365         spin_unlock_irq(&client->buffer_lock);
 366
 367         return have_event;
 368 }
 369
 370 static ssize_t evdev_read(struct file *file, char __user *buffer,
 371                           size_t count, loff_t *ppos)
 372 {
 373         struct evdev_client *client = file->private_data;
 374         struct evdev *evdev = client->evdev;
 375         struct input_event event;
 376         int retval;
 377
 378         if (count < input_event_size())
 379                 return -EINVAL;
 380
 381         if (client->head == client->tail && evdev->exist &&
 382             (file->f_flags & O_NONBLOCK))
 383                 return -EAGAIN;
 384
 385         retval = wait_event_interruptible(evdev->wait,
 386                 client->head != client->tail || !evdev->exist);
 387         if (retval)
 388                 return retval;
 389
 390         if (!evdev->exist)
 391                 return -ENODEV;
 392
 393         while (retval + input_event_size() <= count &&
 394                evdev_fetch_next_event(client, &event)) {
 395
 396                 if (input_event_to_user(buffer + retval, &event))
 397                         return -EFAULT;
 398
 399                 retval += input_event_size();
 400         }
 401
 402         return retval;
 403 }
 404
 405 /* No kernel lock - fine */
 406 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 407 {
 408         struct evdev_client *client = file->private_data;
 409         struct evdev *evdev = client->evdev;
 410         unsigned int mask;
 411
 412         poll_wait(file, &evdev->wait, wait);
 413
 414         mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
 415         if (client->head != client->tail)
 416                 mask |= POLLIN | POLLRDNORM;
 417
 418         return mask;
 419 }
 420
 421 #ifdef CONFIG_COMPAT
 422
 423 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 424 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 425
 426 #ifdef __BIG_ENDIAN
 427 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 428                         unsigned int maxlen, void __user *p, int compat)
 429 {
 430         int len, i;
 431
 432         if (compat) {
 433                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 434                 if (len > maxlen)
 435                         len = maxlen;
 436
 437                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 438                         if (copy_to_user((compat_long_t __user *) p + i,
 439                                          (compat_long_t *) bits +
 440                                                 i + 1 - ((i % 2) << 1),
 441                                          sizeof(compat_long_t)))
 442                                 return -EFAULT;
 443         } else {
 444                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 445                 if (len > maxlen)
 446                         len = maxlen;
 447
 448                 if (copy_to_user(p, bits, len))
 449                         return -EFAULT;
 450         }
 451
 452         return len;
 453 }
 454 #else
 455 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 456                         unsigned int maxlen, void __user *p, int compat)
 457 {
 458         int len = compat ?
 459                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 460                         BITS_TO_LONGS(maxbit) * sizeof(long);
 461
 462         if (len > maxlen)
 463                 len = maxlen;
 464
 465         return copy_to_user(p, bits, len) ? -EFAULT : len;
 466 }
 467 #endif /* __BIG_ENDIAN */
 468
 469 #else
 470
 471 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 472                         unsigned int maxlen, void __user *p, int compat)
 473 {
 474         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 475
 476         if (len > maxlen)
 477                 len = maxlen;
 478
 479         return copy_to_user(p, bits, len) ? -EFAULT : len;
 480 }
 481
 482 #endif /* CONFIG_COMPAT */
 483
 484 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 485 {
 486         int len;
 487
 488         if (!str)
 489                 return -ENOENT;
 490
 491         len = strlen(str) + 1;
 492         if (len > maxlen)
 493                 len = maxlen;
 494
 495         return copy_to_user(p, str, len) ? -EFAULT : len;
 496 }
 497
 498 #define OLD_KEY_MAX     0x1ff
 499 static int handle_eviocgbit(struct input_dev *dev,
 500                             unsigned int type, unsigned int size,
 501                             void __user *p, int compat_mode)
 502 {
 503         static unsigned long keymax_warn_time;
 504         unsigned long *bits;
 505         int len;
 506
 507         switch (type) {
 508
 509         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 510         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 511         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 512         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 513         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 514         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 515         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 516         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 517         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 518         default: return -EINVAL;
 519         }
 520
 521         /*
 522          * Work around bugs in userspace programs that like to do
 523          * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
 524          * should be in bytes, not in bits.
 525          */
 526         if (type == EV_KEY && size == OLD_KEY_MAX) {
 527                 len = OLD_KEY_MAX;
 528                 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
 529                         pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
 530                                    "limiting output to %zu bytes. See "
 531                                    "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
 532                                    OLD_KEY_MAX,
 533                                    BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
 534         }
 535
 536         return bits_to_user(bits, len, size, p, compat_mode);
 537 }
 538 #undef OLD_KEY_MAX
 539
 540 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
 541 {
 542         struct input_keymap_entry ke = {
 543                 .len    = sizeof(unsigned int),
 544                 .flags  = 0,
 545         };
 546         int __user *ip = (int __user *)p;
 547         int error;
 548
 549         /* legacy case */
 550         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 551                 return -EFAULT;
 552
 553         error = input_get_keycode(dev, &ke);
 554         if (error)
 555                 return error;
 556
 557         if (put_user(ke.keycode, ip + 1))
 558                 return -EFAULT;
 559
 560         return 0;
 561 }
 562
 563 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
 564 {
 565         struct input_keymap_entry ke;
 566         int error;
 567
 568         if (copy_from_user(&ke, p, sizeof(ke)))
 569                 return -EFAULT;
 570
 571         error = input_get_keycode(dev, &ke);
 572         if (error)
 573                 return error;
 574
 575         if (copy_to_user(p, &ke, sizeof(ke)))
 576                 return -EFAULT;
 577
 578         return 0;
 579 }
 580
 581 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
 582 {
 583         struct input_keymap_entry ke = {
 584                 .len    = sizeof(unsigned int),
 585                 .flags  = 0,
 586         };
 587         int __user *ip = (int __user *)p;
 588
 589         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 590                 return -EFAULT;
 591
 592         if (get_user(ke.keycode, ip + 1))
 593                 return -EFAULT;
 594
 595         return input_set_keycode(dev, &ke);
 596 }
 597
 598 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
 599 {
 600         struct input_keymap_entry ke;
 601
 602         if (copy_from_user(&ke, p, sizeof(ke)))
 603                 return -EFAULT;
 604
 605         if (ke.len > sizeof(ke.scancode))
 606                 return -EINVAL;
 607
 608         return input_set_keycode(dev, &ke);
 609 }
 610
 611 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 612                            void __user *p, int compat_mode)
 613 {
 614         struct evdev_client *client = file->private_data;
 615         struct evdev *evdev = client->evdev;
 616         struct input_dev *dev = evdev->handle.dev;
 617         struct input_absinfo abs;
 618         struct ff_effect effect;
 619         int __user *ip = (int __user *)p;
 620         unsigned int i, t, u, v;
 621         unsigned int size;
 622         int error;
 623
 624         /* First we check for fixed-length commands */
 625         switch (cmd) {
 626
 627         case EVIOCGVERSION:
 628                 return put_user(EV_VERSION, ip);
 629
 630         case EVIOCGID:
 631                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 632                         return -EFAULT;
 633                 return 0;
 634
 635         case EVIOCGREP:
 636                 if (!test_bit(EV_REP, dev->evbit))
 637                         return -ENOSYS;
 638                 if (put_user(dev->rep[REP_DELAY], ip))
 639                         return -EFAULT;
 640                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 641                         return -EFAULT;
 642                 return 0;
 643
 644         case EVIOCSREP:
 645                 if (!test_bit(EV_REP, dev->evbit))
 646                         return -ENOSYS;
 647                 if (get_user(u, ip))
 648                         return -EFAULT;
 649                 if (get_user(v, ip + 1))
 650                         return -EFAULT;
 651
 652                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 653                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 654
 655                 return 0;
 656
 657         case EVIOCRMFF:
 658                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 659
 660         case EVIOCGEFFECTS:
 661                 i = test_bit(EV_FF, dev->evbit) ?
 662                                 dev->ff->max_effects : 0;
 663                 if (put_user(i, ip))
 664                         return -EFAULT;
 665                 return 0;
 666
 667         case EVIOCGRAB:
 668                 if (p)
 669                         return evdev_grab(evdev, client);
 670                 else
 671                         return evdev_ungrab(evdev, client);
 672
 673         case EVIOCGKEYCODE:
 674                 return evdev_handle_get_keycode(dev, p);
 675
 676         case EVIOCSKEYCODE:
 677                 return evdev_handle_set_keycode(dev, p);
 678
 679         case EVIOCGKEYCODE_V2:
 680                 return evdev_handle_get_keycode_v2(dev, p);
 681
 682         case EVIOCSKEYCODE_V2:
 683                 return evdev_handle_set_keycode_v2(dev, p);
 684         }
 685
 686         size = _IOC_SIZE(cmd);
 687
 688         /* Now check variable-length commands */
 689 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
 690         switch (EVIOC_MASK_SIZE(cmd)) {
 691
 692         case EVIOCGPROP(0):
 693                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
 694                                     size, p, compat_mode);
 695
 696         case EVIOCGKEY(0):
 697                 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
 698
 699         case EVIOCGLED(0):
 700                 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
 701
 702         case EVIOCGSND(0):
 703                 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
 704
 705         case EVIOCGSW(0):
 706                 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
 707
 708         case EVIOCGNAME(0):
 709                 return str_to_user(dev->name, size, p);
 710
 711         case EVIOCGPHYS(0):
 712                 return str_to_user(dev->phys, size, p);
 713
 714         case EVIOCGUNIQ(0):
 715                 return str_to_user(dev->uniq, size, p);
 716
 717         case EVIOC_MASK_SIZE(EVIOCSFF):
 718                 if (input_ff_effect_from_user(p, size, &effect))
 719                         return -EFAULT;
 720
 721                 error = input_ff_upload(dev, &effect, file);
 722
 723                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 724                         return -EFAULT;
 725
 726                 return error;
 727         }
 728
 729         /* Multi-number variable-length handlers */
 730         if (_IOC_TYPE(cmd) != 'E')
 731                 return -EINVAL;
 732
 733         if (_IOC_DIR(cmd) == _IOC_READ) {
 734
 735                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
 736                         return handle_eviocgbit(dev,
 737                                                 _IOC_NR(cmd) & EV_MAX, size,
 738                                                 p, compat_mode);
 739
 740                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 741
 742                         if (!dev->absinfo)
 743                                 return -EINVAL;
 744
 745                         t = _IOC_NR(cmd) & ABS_MAX;
 746                         abs = dev->absinfo[t];
 747
 748                         if (copy_to_user(p, &abs, min_t(size_t,
 749                                         size, sizeof(struct input_absinfo))))
 750                                 return -EFAULT;
 751
 752                         return 0;
 753                 }
 754         }
 755
 756         if (_IOC_DIR(cmd) == _IOC_WRITE) {
 757
 758                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 759
 760                         if (!dev->absinfo)
 761                                 return -EINVAL;
 762
 763                         t = _IOC_NR(cmd) & ABS_MAX;
 764
 765                         if (copy_from_user(&abs, p, min_t(size_t,
 766                                         size, sizeof(struct input_absinfo))))
 767                                 return -EFAULT;
 768
 769                         if (size < sizeof(struct input_absinfo))
 770                                 abs.resolution = 0;
 771
 772                         /* We can't change number of reserved MT slots */
 773                         if (t == ABS_MT_SLOT)
 774                                 return -EINVAL;
 775
 776                         /*
 777                          * Take event lock to ensure that we are not
 778                          * changing device parameters in the middle
 779                          * of event.
 780                          */
 781                         spin_lock_irq(&dev->event_lock);
 782                         dev->absinfo[t] = abs;
 783                         spin_unlock_irq(&dev->event_lock);
 784
 785                         return 0;
 786                 }
 787         }
 788
 789         return -EINVAL;
 790 }
 791
 792 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 793                                 void __user *p, int compat_mode)
 794 {
 795         struct evdev_client *client = file->private_data;
 796         struct evdev *evdev = client->evdev;
 797         int retval;
 798
 799         retval = mutex_lock_interruptible(&evdev->mutex);
 800         if (retval)
 801                 return retval;
 802
 803         if (!evdev->exist) {
 804                 retval = -ENODEV;
 805                 goto out;
 806         }
 807
 808         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
 809
 810  out:
 811         mutex_unlock(&evdev->mutex);
 812         return retval;
 813 }
 814
 815 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 816 {
 817         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
 818 }
 819
 820 #ifdef CONFIG_COMPAT
 821 static long evdev_ioctl_compat(struct file *file,
 822                                 unsigned int cmd, unsigned long arg)
 823 {
 824         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
 825 }
 826 #endif
 827
 828 static const struct file_operations evdev_fops = {
 829         .owner          = THIS_MODULE,
 830         .read           = evdev_read,
 831         .write          = evdev_write,
 832         .poll           = evdev_poll,
 833         .open           = evdev_open,
 834         .release        = evdev_release,
 835         .unlocked_ioctl = evdev_ioctl,
 836 #ifdef CONFIG_COMPAT
 837         .compat_ioctl   = evdev_ioctl_compat,
 838 #endif
 839         .fasync         = evdev_fasync,
 840         .flush          = evdev_flush,
 841         .llseek         = no_llseek,
 842 };
 843
 844 static int evdev_install_chrdev(struct evdev *evdev)
 845 {
 846         /*
 847          * No need to do any locking here as calls to connect and
 848          * disconnect are serialized by the input core
 849          */
 850         evdev_table[evdev->minor] = evdev;
 851         return 0;
 852 }
 853
 854 static void evdev_remove_chrdev(struct evdev *evdev)
 855 {
 856         /*
 857          * Lock evdev table to prevent race with evdev_open()
 858          */
 859         mutex_lock(&evdev_table_mutex);
 860         evdev_table[evdev->minor] = NULL;
 861         mutex_unlock(&evdev_table_mutex);
 862 }
 863
 864 /*
 865  * Mark device non-existent. This disables writes, ioctls and
 866  * prevents new users from opening the device. Already posted
 867  * blocking reads will stay, however new ones will fail.
 868  */
 869 static void evdev_mark_dead(struct evdev *evdev)
 870 {
 871         mutex_lock(&evdev->mutex);
 872         evdev->exist = false;
 873         mutex_unlock(&evdev->mutex);
 874 }
 875
 876 static void evdev_cleanup(struct evdev *evdev)
 877 {
 878         struct input_handle *handle = &evdev->handle;
 879
 880         evdev_mark_dead(evdev);
 881         evdev_hangup(evdev);
 882         evdev_remove_chrdev(evdev);
 883
 884         /* evdev is marked dead so no one else accesses evdev->open */
 885         if (evdev->open) {
 886                 input_flush_device(handle, NULL);
 887                 input_close_device(handle);
 888         }
 889 }
 890
 891 /*
 892  * Create new evdev device. Note that input core serializes calls
 893  * to connect and disconnect so we don't need to lock evdev_table here.
 894  */
 895 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
 896                          const struct input_device_id *id)
 897 {
 898         struct evdev *evdev;
 899         int minor;
 900         int error;
 901
 902         for (minor = 0; minor < EVDEV_MINORS; minor++)
 903                 if (!evdev_table[minor])
 904                         break;
 905
 906         if (minor == EVDEV_MINORS) {
 907                 pr_err("no more free evdev devices\n");
 908                 return -ENFILE;
 909         }
 910
 911         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
 912         if (!evdev)
 913                 return -ENOMEM;
 914
 915         INIT_LIST_HEAD(&evdev->client_list);
 916         spin_lock_init(&evdev->client_lock);
 917         mutex_init(&evdev->mutex);
 918         init_waitqueue_head(&evdev->wait);
 919
 920         dev_set_name(&evdev->dev, "event%d", minor);
 921         evdev->exist = true;
 922         evdev->minor = minor;
 923
 924         evdev->handle.dev = input_get_device(dev);
 925         evdev->handle.name = dev_name(&evdev->dev);
 926         evdev->handle.handler = handler;
 927         evdev->handle.private = evdev;
 928
 929         evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 930         evdev->dev.class = &input_class;
 931         evdev->dev.parent = &dev->dev;
 932         evdev->dev.release = evdev_free;
 933         device_initialize(&evdev->dev);
 934
 935         error = input_register_handle(&evdev->handle);
 936         if (error)
 937                 goto err_free_evdev;
 938
 939         error = evdev_install_chrdev(evdev);
 940         if (error)
 941                 goto err_unregister_handle;
 942
 943         error = device_add(&evdev->dev);
 944         if (error)
 945                 goto err_cleanup_evdev;
 946
 947         return 0;
 948
 949  err_cleanup_evdev:
 950         evdev_cleanup(evdev);
 951  err_unregister_handle:
 952         input_unregister_handle(&evdev->handle);
 953  err_free_evdev:
 954         put_device(&evdev->dev);
 955         return error;
 956 }
 957
 958 static void evdev_disconnect(struct input_handle *handle)
 959 {
 960         struct evdev *evdev = handle->private;
 961
 962         device_del(&evdev->dev);
 963         evdev_cleanup(evdev);
 964         input_unregister_handle(handle);
 965         put_device(&evdev->dev);
 966 }
 967
 968 static const struct input_device_id evdev_ids[] = {
 969         { .driver_info = 1 },   /* Matches all devices */
 970         { },                    /* Terminating zero entry */
 971 };
 972
 973 MODULE_DEVICE_TABLE(input, evdev_ids);
 974
 975 static struct input_handler evdev_handler = {
 976         .event          = evdev_event,
 977         .connect        = evdev_connect,
 978         .disconnect     = evdev_disconnect,
 979         .fops           = &evdev_fops,
 980         .minor          = EVDEV_MINOR_BASE,
 981         .name           = "evdev",
 982         .id_table       = evdev_ids,
 983 };
 984
 985 static int __init evdev_init(void)
 986 {
 987         return input_register_handler(&evdev_handler);
 988 }
 989
 990 static void __exit evdev_exit(void)
 991 {
 992         input_unregister_handler(&evdev_handler);
 993 }
 994
 995 module_init(evdev_init);
 996 module_exit(evdev_exit);
 997
 998 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
 999 MODULE_DESCRIPTION("Input driver event char devices");
1000 MODULE_LICENSE("GPL");