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         unsigned int head;
  43         unsigned int tail;
  44         unsigned int packet_head; /* [future] position of the first element of next packet */
  45         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  46         struct fasync_struct *fasync;
  47         struct evdev *evdev;
  48         struct list_head node;
  49         unsigned int bufsize;
  50         struct input_event buffer[];
  51 };
  52
  53 static struct evdev *evdev_table[EVDEV_MINORS];
  54 static DEFINE_MUTEX(evdev_table_mutex);
  55
  56 static void evdev_pass_event(struct evdev_client *client,
  57                              struct input_event *event)
  58 {
  59         /* Interrupts are disabled, just acquire the lock. */
  60         spin_lock(&client->buffer_lock);
  61
  62         client->buffer[client->head++] = *event;
  63         client->head &= client->bufsize - 1;
  64
  65         if (unlikely(client->head == client->tail)) {
  66                 /*
  67                  * This effectively "drops" all unconsumed events, leaving
  68                  * EV_SYN/SYN_DROPPED plus the newest event in the queue.
  69                  */
  70                 client->tail = (client->head - 2) & (client->bufsize - 1);
  71
  72                 client->buffer[client->tail].time = event->time;
  73                 client->buffer[client->tail].type = EV_SYN;
  74                 client->buffer[client->tail].code = SYN_DROPPED;
  75                 client->buffer[client->tail].value = 0;
  76
  77                 client->packet_head = client->tail;
  78         }
  79
  80         if (event->type == EV_SYN && event->code == SYN_REPORT) {
  81                 client->packet_head = client->head;
  82                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
  83         }
  84
  85         spin_unlock(&client->buffer_lock);
  86 }
  87
  88 /*
  89  * Pass incoming event to all connected clients.
  90  */
  91 static void evdev_event(struct input_handle *handle,
  92                         unsigned int type, unsigned int code, int value)
  93 {
  94         struct evdev *evdev = handle->private;
  95         struct evdev_client *client;
  96         struct input_event event;
  97
  98         do_gettimeofday(&event.time);
  99         event.type = type;
 100         event.code = code;
 101         event.value = value;
 102
 103         rcu_read_lock();
 104
 105         client = rcu_dereference(evdev->grab);
 106         if (client)
 107                 evdev_pass_event(client, &event);
 108         else
 109                 list_for_each_entry_rcu(client, &evdev->client_list, node)
 110                         evdev_pass_event(client, &event);
 111
 112         rcu_read_unlock();
 113
 114         wake_up_interruptible(&evdev->wait);
 115 }
 116
 117 static int evdev_fasync(int fd, struct file *file, int on)
 118 {
 119         struct evdev_client *client = file->private_data;
 120
 121         return fasync_helper(fd, file, on, &client->fasync);
 122 }
 123
 124 static int evdev_flush(struct file *file, fl_owner_t id)
 125 {
 126         struct evdev_client *client = file->private_data;
 127         struct evdev *evdev = client->evdev;
 128         int retval;
 129
 130         retval = mutex_lock_interruptible(&evdev->mutex);
 131         if (retval)
 132                 return retval;
 133
 134         if (!evdev->exist)
 135                 retval = -ENODEV;
 136         else
 137                 retval = input_flush_device(&evdev->handle, file);
 138
 139         mutex_unlock(&evdev->mutex);
 140         return retval;
 141 }
 142
 143 static void evdev_free(struct device *dev)
 144 {
 145         struct evdev *evdev = container_of(dev, struct evdev, dev);
 146
 147         input_put_device(evdev->handle.dev);
 148         kfree(evdev);
 149 }
 150
 151 /*
 152  * Grabs an event device (along with underlying input device).
 153  * This function is called with evdev->mutex taken.
 154  */
 155 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 156 {
 157         int error;
 158
 159         if (evdev->grab)
 160                 return -EBUSY;
 161
 162         error = input_grab_device(&evdev->handle);
 163         if (error)
 164                 return error;
 165
 166         rcu_assign_pointer(evdev->grab, client);
 167
 168         return 0;
 169 }
 170
 171 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 172 {
 173         if (evdev->grab != client)
 174                 return  -EINVAL;
 175
 176         rcu_assign_pointer(evdev->grab, NULL);
 177         synchronize_rcu();
 178         input_release_device(&evdev->handle);
 179
 180         return 0;
 181 }
 182
 183 static void evdev_attach_client(struct evdev *evdev,
 184                                 struct evdev_client *client)
 185 {
 186         spin_lock(&evdev->client_lock);
 187         list_add_tail_rcu(&client->node, &evdev->client_list);
 188         spin_unlock(&evdev->client_lock);
 189 }
 190
 191 static void evdev_detach_client(struct evdev *evdev,
 192                                 struct evdev_client *client)
 193 {
 194         spin_lock(&evdev->client_lock);
 195         list_del_rcu(&client->node);
 196         spin_unlock(&evdev->client_lock);
 197         synchronize_rcu();
 198 }
 199
 200 static int evdev_open_device(struct evdev *evdev)
 201 {
 202         int retval;
 203
 204         retval = mutex_lock_interruptible(&evdev->mutex);
 205         if (retval)
 206                 return retval;
 207
 208         if (!evdev->exist)
 209                 retval = -ENODEV;
 210         else if (!evdev->open++) {
 211                 retval = input_open_device(&evdev->handle);
 212                 if (retval)
 213                         evdev->open--;
 214         }
 215
 216         mutex_unlock(&evdev->mutex);
 217         return retval;
 218 }
 219
 220 static void evdev_close_device(struct evdev *evdev)
 221 {
 222         mutex_lock(&evdev->mutex);
 223
 224         if (evdev->exist && !--evdev->open)
 225                 input_close_device(&evdev->handle);
 226
 227         mutex_unlock(&evdev->mutex);
 228 }
 229
 230 /*
 231  * Wake up users waiting for IO so they can disconnect from
 232  * dead device.
 233  */
 234 static void evdev_hangup(struct evdev *evdev)
 235 {
 236         struct evdev_client *client;
 237
 238         spin_lock(&evdev->client_lock);
 239         list_for_each_entry(client, &evdev->client_list, node)
 240                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 241         spin_unlock(&evdev->client_lock);
 242
 243         wake_up_interruptible(&evdev->wait);
 244 }
 245
 246 static int evdev_release(struct inode *inode, struct file *file)
 247 {
 248         struct evdev_client *client = file->private_data;
 249         struct evdev *evdev = client->evdev;
 250
 251         mutex_lock(&evdev->mutex);
 252         if (evdev->grab == client)
 253                 evdev_ungrab(evdev, client);
 254         mutex_unlock(&evdev->mutex);
 255
 256         evdev_detach_client(evdev, client);
 257         kfree(client);
 258
 259         evdev_close_device(evdev);
 260         put_device(&evdev->dev);
 261
 262         return 0;
 263 }
 264
 265 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 266 {
 267         unsigned int n_events =
 268                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 269                     EVDEV_MIN_BUFFER_SIZE);
 270
 271         return roundup_pow_of_two(n_events);
 272 }
 273
 274 static int evdev_open(struct inode *inode, struct file *file)
 275 {
 276         struct evdev *evdev;
 277         struct evdev_client *client;
 278         int i = iminor(inode) - EVDEV_MINOR_BASE;
 279         unsigned int bufsize;
 280         int error;
 281
 282         if (i >= EVDEV_MINORS)
 283                 return -ENODEV;
 284
 285         error = mutex_lock_interruptible(&evdev_table_mutex);
 286         if (error)
 287                 return error;
 288         evdev = evdev_table[i];
 289         if (evdev)
 290                 get_device(&evdev->dev);
 291         mutex_unlock(&evdev_table_mutex);
 292
 293         if (!evdev)
 294                 return -ENODEV;
 295
 296         bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 297
 298         client = kzalloc(sizeof(struct evdev_client) +
 299                                 bufsize * sizeof(struct input_event),
 300                          GFP_KERNEL);
 301         if (!client) {
 302                 error = -ENOMEM;
 303                 goto err_put_evdev;
 304         }
 305
 306         client->bufsize = bufsize;
 307         spin_lock_init(&client->buffer_lock);
 308         client->evdev = evdev;
 309         evdev_attach_client(evdev, client);
 310
 311         error = evdev_open_device(evdev);
 312         if (error)
 313                 goto err_free_client;
 314
 315         file->private_data = client;
 316         nonseekable_open(inode, file);
 317
 318         return 0;
 319
 320  err_free_client:
 321         evdev_detach_client(evdev, client);
 322         kfree(client);
 323  err_put_evdev:
 324         put_device(&evdev->dev);
 325         return error;
 326 }
 327
 328 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 329                            size_t count, loff_t *ppos)
 330 {
 331         struct evdev_client *client = file->private_data;
 332         struct evdev *evdev = client->evdev;
 333         struct input_event event;
 334         int retval;
 335
 336         if (count < input_event_size())
 337                 return -EINVAL;
 338
 339         retval = mutex_lock_interruptible(&evdev->mutex);
 340         if (retval)
 341                 return retval;
 342
 343         if (!evdev->exist) {
 344                 retval = -ENODEV;
 345                 goto out;
 346         }
 347
 348         do {
 349                 if (input_event_from_user(buffer + retval, &event)) {
 350                         retval = -EFAULT;
 351                         goto out;
 352                 }
 353                 retval += input_event_size();
 354
 355                 input_inject_event(&evdev->handle,
 356                                    event.type, event.code, event.value);
 357         } while (retval + input_event_size() <= count);
 358
 359  out:
 360         mutex_unlock(&evdev->mutex);
 361         return retval;
 362 }
 363
 364 static int evdev_fetch_next_event(struct evdev_client *client,
 365                                   struct input_event *event)
 366 {
 367         int have_event;
 368
 369         spin_lock_irq(&client->buffer_lock);
 370
 371         have_event = client->head != client->tail;
 372         if (have_event) {
 373                 *event = client->buffer[client->tail++];
 374                 client->tail &= client->bufsize - 1;
 375         }
 376
 377         spin_unlock_irq(&client->buffer_lock);
 378
 379         return have_event;
 380 }
 381
 382 static ssize_t evdev_read(struct file *file, char __user *buffer,
 383                           size_t count, loff_t *ppos)
 384 {
 385         struct evdev_client *client = file->private_data;
 386         struct evdev *evdev = client->evdev;
 387         struct input_event event;
 388         int retval;
 389
 390         if (count < input_event_size())
 391                 return -EINVAL;
 392
 393         if (client->packet_head == client->tail && evdev->exist &&
 394             (file->f_flags & O_NONBLOCK))
 395                 return -EAGAIN;
 396
 397         retval = wait_event_interruptible(evdev->wait,
 398                 client->packet_head != client->tail || !evdev->exist);
 399         if (retval)
 400                 return retval;
 401
 402         if (!evdev->exist)
 403                 return -ENODEV;
 404
 405         while (retval + input_event_size() <= count &&
 406                evdev_fetch_next_event(client, &event)) {
 407
 408                 if (input_event_to_user(buffer + retval, &event))
 409                         return -EFAULT;
 410
 411                 retval += input_event_size();
 412         }
 413
 414         return retval;
 415 }
 416
 417 /* No kernel lock - fine */
 418 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 419 {
 420         struct evdev_client *client = file->private_data;
 421         struct evdev *evdev = client->evdev;
 422         unsigned int mask;
 423
 424         poll_wait(file, &evdev->wait, wait);
 425
 426         mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
 427         if (client->packet_head != client->tail)
 428                 mask |= POLLIN | POLLRDNORM;
 429
 430         return mask;
 431 }
 432
 433 #ifdef CONFIG_COMPAT
 434
 435 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 436 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 437
 438 #ifdef __BIG_ENDIAN
 439 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 440                         unsigned int maxlen, void __user *p, int compat)
 441 {
 442         int len, i;
 443
 444         if (compat) {
 445                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 446                 if (len > maxlen)
 447                         len = maxlen;
 448
 449                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 450                         if (copy_to_user((compat_long_t __user *) p + i,
 451                                          (compat_long_t *) bits +
 452                                                 i + 1 - ((i % 2) << 1),
 453                                          sizeof(compat_long_t)))
 454                                 return -EFAULT;
 455         } else {
 456                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 457                 if (len > maxlen)
 458                         len = maxlen;
 459
 460                 if (copy_to_user(p, bits, len))
 461                         return -EFAULT;
 462         }
 463
 464         return len;
 465 }
 466 #else
 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 = compat ?
 471                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 472                         BITS_TO_LONGS(maxbit) * sizeof(long);
 473
 474         if (len > maxlen)
 475                 len = maxlen;
 476
 477         return copy_to_user(p, bits, len) ? -EFAULT : len;
 478 }
 479 #endif /* __BIG_ENDIAN */
 480
 481 #else
 482
 483 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 484                         unsigned int maxlen, void __user *p, int compat)
 485 {
 486         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 487
 488         if (len > maxlen)
 489                 len = maxlen;
 490
 491         return copy_to_user(p, bits, len) ? -EFAULT : len;
 492 }
 493
 494 #endif /* CONFIG_COMPAT */
 495
 496 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 497 {
 498         int len;
 499
 500         if (!str)
 501                 return -ENOENT;
 502
 503         len = strlen(str) + 1;
 504         if (len > maxlen)
 505                 len = maxlen;
 506
 507         return copy_to_user(p, str, len) ? -EFAULT : len;
 508 }
 509
 510 #define OLD_KEY_MAX     0x1ff
 511 static int handle_eviocgbit(struct input_dev *dev,
 512                             unsigned int type, unsigned int size,
 513                             void __user *p, int compat_mode)
 514 {
 515         static unsigned long keymax_warn_time;
 516         unsigned long *bits;
 517         int len;
 518
 519         switch (type) {
 520
 521         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 522         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 523         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 524         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 525         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 526         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 527         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 528         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 529         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 530         default: return -EINVAL;
 531         }
 532
 533         /*
 534          * Work around bugs in userspace programs that like to do
 535          * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
 536          * should be in bytes, not in bits.
 537          */
 538         if (type == EV_KEY && size == OLD_KEY_MAX) {
 539                 len = OLD_KEY_MAX;
 540                 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
 541                         pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
 542                                    "limiting output to %zu bytes. See "
 543                                    "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
 544                                    OLD_KEY_MAX,
 545                                    BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
 546         }
 547
 548         return bits_to_user(bits, len, size, p, compat_mode);
 549 }
 550 #undef OLD_KEY_MAX
 551
 552 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
 553 {
 554         struct input_keymap_entry ke = {
 555                 .len    = sizeof(unsigned int),
 556                 .flags  = 0,
 557         };
 558         int __user *ip = (int __user *)p;
 559         int error;
 560
 561         /* legacy case */
 562         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 563                 return -EFAULT;
 564
 565         error = input_get_keycode(dev, &ke);
 566         if (error)
 567                 return error;
 568
 569         if (put_user(ke.keycode, ip + 1))
 570                 return -EFAULT;
 571
 572         return 0;
 573 }
 574
 575 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
 576 {
 577         struct input_keymap_entry ke;
 578         int error;
 579
 580         if (copy_from_user(&ke, p, sizeof(ke)))
 581                 return -EFAULT;
 582
 583         error = input_get_keycode(dev, &ke);
 584         if (error)
 585                 return error;
 586
 587         if (copy_to_user(p, &ke, sizeof(ke)))
 588                 return -EFAULT;
 589
 590         return 0;
 591 }
 592
 593 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
 594 {
 595         struct input_keymap_entry ke = {
 596                 .len    = sizeof(unsigned int),
 597                 .flags  = 0,
 598         };
 599         int __user *ip = (int __user *)p;
 600
 601         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 602                 return -EFAULT;
 603
 604         if (get_user(ke.keycode, ip + 1))
 605                 return -EFAULT;
 606
 607         return input_set_keycode(dev, &ke);
 608 }
 609
 610 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
 611 {
 612         struct input_keymap_entry ke;
 613
 614         if (copy_from_user(&ke, p, sizeof(ke)))
 615                 return -EFAULT;
 616
 617         if (ke.len > sizeof(ke.scancode))
 618                 return -EINVAL;
 619
 620         return input_set_keycode(dev, &ke);
 621 }
 622
 623 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 624                            void __user *p, int compat_mode)
 625 {
 626         struct evdev_client *client = file->private_data;
 627         struct evdev *evdev = client->evdev;
 628         struct input_dev *dev = evdev->handle.dev;
 629         struct input_absinfo abs;
 630         struct ff_effect effect;
 631         int __user *ip = (int __user *)p;
 632         unsigned int i, t, u, v;
 633         unsigned int size;
 634         int error;
 635
 636         /* First we check for fixed-length commands */
 637         switch (cmd) {
 638
 639         case EVIOCGVERSION:
 640                 return put_user(EV_VERSION, ip);
 641
 642         case EVIOCGID:
 643                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 644                         return -EFAULT;
 645                 return 0;
 646
 647         case EVIOCGREP:
 648                 if (!test_bit(EV_REP, dev->evbit))
 649                         return -ENOSYS;
 650                 if (put_user(dev->rep[REP_DELAY], ip))
 651                         return -EFAULT;
 652                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 653                         return -EFAULT;
 654                 return 0;
 655
 656         case EVIOCSREP:
 657                 if (!test_bit(EV_REP, dev->evbit))
 658                         return -ENOSYS;
 659                 if (get_user(u, ip))
 660                         return -EFAULT;
 661                 if (get_user(v, ip + 1))
 662                         return -EFAULT;
 663
 664                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 665                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 666
 667                 return 0;
 668
 669         case EVIOCRMFF:
 670                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 671
 672         case EVIOCGEFFECTS:
 673                 i = test_bit(EV_FF, dev->evbit) ?
 674                                 dev->ff->max_effects : 0;
 675                 if (put_user(i, ip))
 676                         return -EFAULT;
 677                 return 0;
 678
 679         case EVIOCGRAB:
 680                 if (p)
 681                         return evdev_grab(evdev, client);
 682                 else
 683                         return evdev_ungrab(evdev, client);
 684
 685         case EVIOCGKEYCODE:
 686                 return evdev_handle_get_keycode(dev, p);
 687
 688         case EVIOCSKEYCODE:
 689                 return evdev_handle_set_keycode(dev, p);
 690
 691         case EVIOCGKEYCODE_V2:
 692                 return evdev_handle_get_keycode_v2(dev, p);
 693
 694         case EVIOCSKEYCODE_V2:
 695                 return evdev_handle_set_keycode_v2(dev, p);
 696         }
 697
 698         size = _IOC_SIZE(cmd);
 699
 700         /* Now check variable-length commands */
 701 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
 702         switch (EVIOC_MASK_SIZE(cmd)) {
 703
 704         case EVIOCGPROP(0):
 705                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
 706                                     size, p, compat_mode);
 707
 708         case EVIOCGKEY(0):
 709                 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
 710
 711         case EVIOCGLED(0):
 712                 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
 713
 714         case EVIOCGSND(0):
 715                 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
 716
 717         case EVIOCGSW(0):
 718                 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
 719
 720         case EVIOCGNAME(0):
 721                 return str_to_user(dev->name, size, p);
 722
 723         case EVIOCGPHYS(0):
 724                 return str_to_user(dev->phys, size, p);
 725
 726         case EVIOCGUNIQ(0):
 727                 return str_to_user(dev->uniq, size, p);
 728
 729         case EVIOC_MASK_SIZE(EVIOCSFF):
 730                 if (input_ff_effect_from_user(p, size, &effect))
 731                         return -EFAULT;
 732
 733                 error = input_ff_upload(dev, &effect, file);
 734
 735                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 736                         return -EFAULT;
 737
 738                 return error;
 739         }
 740
 741         /* Multi-number variable-length handlers */
 742         if (_IOC_TYPE(cmd) != 'E')
 743                 return -EINVAL;
 744
 745         if (_IOC_DIR(cmd) == _IOC_READ) {
 746
 747                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
 748                         return handle_eviocgbit(dev,
 749                                                 _IOC_NR(cmd) & EV_MAX, size,
 750                                                 p, compat_mode);
 751
 752                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 753
 754                         if (!dev->absinfo)
 755                                 return -EINVAL;
 756
 757                         t = _IOC_NR(cmd) & ABS_MAX;
 758                         abs = dev->absinfo[t];
 759
 760                         if (copy_to_user(p, &abs, min_t(size_t,
 761                                         size, sizeof(struct input_absinfo))))
 762                                 return -EFAULT;
 763
 764                         return 0;
 765                 }
 766         }
 767
 768         if (_IOC_DIR(cmd) == _IOC_WRITE) {
 769
 770                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 771
 772                         if (!dev->absinfo)
 773                                 return -EINVAL;
 774
 775                         t = _IOC_NR(cmd) & ABS_MAX;
 776
 777                         if (copy_from_user(&abs, p, min_t(size_t,
 778                                         size, sizeof(struct input_absinfo))))
 779                                 return -EFAULT;
 780
 781                         if (size < sizeof(struct input_absinfo))
 782                                 abs.resolution = 0;
 783
 784                         /* We can't change number of reserved MT slots */
 785                         if (t == ABS_MT_SLOT)
 786                                 return -EINVAL;
 787
 788                         /*
 789                          * Take event lock to ensure that we are not
 790                          * changing device parameters in the middle
 791                          * of event.
 792                          */
 793                         spin_lock_irq(&dev->event_lock);
 794                         dev->absinfo[t] = abs;
 795                         spin_unlock_irq(&dev->event_lock);
 796
 797                         return 0;
 798                 }
 799         }
 800
 801         return -EINVAL;
 802 }
 803
 804 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 805                                 void __user *p, int compat_mode)
 806 {
 807         struct evdev_client *client = file->private_data;
 808         struct evdev *evdev = client->evdev;
 809         int retval;
 810
 811         retval = mutex_lock_interruptible(&evdev->mutex);
 812         if (retval)
 813                 return retval;
 814
 815         if (!evdev->exist) {
 816                 retval = -ENODEV;
 817                 goto out;
 818         }
 819
 820         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
 821
 822  out:
 823         mutex_unlock(&evdev->mutex);
 824         return retval;
 825 }
 826
 827 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 828 {
 829         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
 830 }
 831
 832 #ifdef CONFIG_COMPAT
 833 static long evdev_ioctl_compat(struct file *file,
 834                                 unsigned int cmd, unsigned long arg)
 835 {
 836         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
 837 }
 838 #endif
 839
 840 static const struct file_operations evdev_fops = {
 841         .owner          = THIS_MODULE,
 842         .read           = evdev_read,
 843         .write          = evdev_write,
 844         .poll           = evdev_poll,
 845         .open           = evdev_open,
 846         .release        = evdev_release,
 847         .unlocked_ioctl = evdev_ioctl,
 848 #ifdef CONFIG_COMPAT
 849         .compat_ioctl   = evdev_ioctl_compat,
 850 #endif
 851         .fasync         = evdev_fasync,
 852         .flush          = evdev_flush,
 853         .llseek         = no_llseek,
 854 };
 855
 856 static int evdev_install_chrdev(struct evdev *evdev)
 857 {
 858         /*
 859          * No need to do any locking here as calls to connect and
 860          * disconnect are serialized by the input core
 861          */
 862         evdev_table[evdev->minor] = evdev;
 863         return 0;
 864 }
 865
 866 static void evdev_remove_chrdev(struct evdev *evdev)
 867 {
 868         /*
 869          * Lock evdev table to prevent race with evdev_open()
 870          */
 871         mutex_lock(&evdev_table_mutex);
 872         evdev_table[evdev->minor] = NULL;
 873         mutex_unlock(&evdev_table_mutex);
 874 }
 875
 876 /*
 877  * Mark device non-existent. This disables writes, ioctls and
 878  * prevents new users from opening the device. Already posted
 879  * blocking reads will stay, however new ones will fail.
 880  */
 881 static void evdev_mark_dead(struct evdev *evdev)
 882 {
 883         mutex_lock(&evdev->mutex);
 884         evdev->exist = false;
 885         mutex_unlock(&evdev->mutex);
 886 }
 887
 888 static void evdev_cleanup(struct evdev *evdev)
 889 {
 890         struct input_handle *handle = &evdev->handle;
 891
 892         evdev_mark_dead(evdev);
 893         evdev_hangup(evdev);
 894         evdev_remove_chrdev(evdev);
 895
 896         /* evdev is marked dead so no one else accesses evdev->open */
 897         if (evdev->open) {
 898                 input_flush_device(handle, NULL);
 899                 input_close_device(handle);
 900         }
 901 }
 902
 903 /*
 904  * Create new evdev device. Note that input core serializes calls
 905  * to connect and disconnect so we don't need to lock evdev_table here.
 906  */
 907 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
 908                          const struct input_device_id *id)
 909 {
 910         struct evdev *evdev;
 911         int minor;
 912         int error;
 913
 914         for (minor = 0; minor < EVDEV_MINORS; minor++)
 915                 if (!evdev_table[minor])
 916                         break;
 917
 918         if (minor == EVDEV_MINORS) {
 919                 pr_err("no more free evdev devices\n");
 920                 return -ENFILE;
 921         }
 922
 923         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
 924         if (!evdev)
 925                 return -ENOMEM;
 926
 927         INIT_LIST_HEAD(&evdev->client_list);
 928         spin_lock_init(&evdev->client_lock);
 929         mutex_init(&evdev->mutex);
 930         init_waitqueue_head(&evdev->wait);
 931
 932         dev_set_name(&evdev->dev, "event%d", minor);
 933         evdev->exist = true;
 934         evdev->minor = minor;
 935
 936         evdev->handle.dev = input_get_device(dev);
 937         evdev->handle.name = dev_name(&evdev->dev);
 938         evdev->handle.handler = handler;
 939         evdev->handle.private = evdev;
 940
 941         evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 942         evdev->dev.class = &input_class;
 943         evdev->dev.parent = &dev->dev;
 944         evdev->dev.release = evdev_free;
 945         device_initialize(&evdev->dev);
 946
 947         error = input_register_handle(&evdev->handle);
 948         if (error)
 949                 goto err_free_evdev;
 950
 951         error = evdev_install_chrdev(evdev);
 952         if (error)
 953                 goto err_unregister_handle;
 954
 955         error = device_add(&evdev->dev);
 956         if (error)
 957                 goto err_cleanup_evdev;
 958
 959         return 0;
 960
 961  err_cleanup_evdev:
 962         evdev_cleanup(evdev);
 963  err_unregister_handle:
 964         input_unregister_handle(&evdev->handle);
 965  err_free_evdev:
 966         put_device(&evdev->dev);
 967         return error;
 968 }
 969
 970 static void evdev_disconnect(struct input_handle *handle)
 971 {
 972         struct evdev *evdev = handle->private;
 973
 974         device_del(&evdev->dev);
 975         evdev_cleanup(evdev);
 976         input_unregister_handle(handle);
 977         put_device(&evdev->dev);
 978 }
 979
 980 static const struct input_device_id evdev_ids[] = {
 981         { .driver_info = 1 },   /* Matches all devices */
 982         { },                    /* Terminating zero entry */
 983 };
 984
 985 MODULE_DEVICE_TABLE(input, evdev_ids);
 986
 987 static struct input_handler evdev_handler = {
 988         .event          = evdev_event,
 989         .connect        = evdev_connect,
 990         .disconnect     = evdev_disconnect,
 991         .fops           = &evdev_fops,
 992         .minor          = EVDEV_MINOR_BASE,
 993         .name           = "evdev",
 994         .id_table       = evdev_ids,
 995 };
 996
 997 static int __init evdev_init(void)
 998 {
 999         return input_register_handler(&evdev_handler);
1000 }
1001
1002 static void __exit evdev_exit(void)
1003 {
1004         input_unregister_handler(&evdev_handler);
1005 }
1006
1007 module_init(evdev_init);
1008 module_exit(evdev_exit);
1009
1010 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1011 MODULE_DESCRIPTION("Input driver event char devices");
1012 MODULE_LICENSE("GPL");