drivers/input/evdev.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Event char devices, giving access to raw input device events.
   4  *
   5  * Copyright (c) 1999-2002 Vojtech Pavlik
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #define EVDEV_MINOR_BASE        64
  11 #define EVDEV_MINORS            32
  12 #define EVDEV_MIN_BUFFER_SIZE   64U
  13 #define EVDEV_BUF_PACKETS       8
  14
  15 #include <linux/poll.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/vmalloc.h>
  19 #include <linux/mm.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/input/mt.h>
  23 #include <linux/major.h>
  24 #include <linux/device.h>
  25 #include <linux/cdev.h>
  26 #include "input-compat.h"
  27
  28 struct evdev {
  29         int open;
  30         struct input_handle handle;
  31         wait_queue_head_t wait;
  32         struct evdev_client __rcu *grab;
  33         struct list_head client_list;
  34         spinlock_t client_lock; /* protects client_list */
  35         struct mutex mutex;
  36         struct device dev;
  37         struct cdev cdev;
  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         enum input_clock_type clk_type;
  50         bool revoked;
  51         unsigned long *evmasks[EV_CNT];
  52         unsigned int bufsize;
  53         struct input_event buffer[];
  54 };
  55
  56 static size_t evdev_get_mask_cnt(unsigned int type)
  57 {
  58         static const size_t counts[EV_CNT] = {
  59                 /* EV_SYN==0 is EV_CNT, _not_ SYN_CNT, see EVIOCGBIT */
  60                 [EV_SYN]        = EV_CNT,
  61                 [EV_KEY]        = KEY_CNT,
  62                 [EV_REL]        = REL_CNT,
  63                 [EV_ABS]        = ABS_CNT,
  64                 [EV_MSC]        = MSC_CNT,
  65                 [EV_SW]         = SW_CNT,
  66                 [EV_LED]        = LED_CNT,
  67                 [EV_SND]        = SND_CNT,
  68                 [EV_FF]         = FF_CNT,
  69         };
  70
  71         return (type < EV_CNT) ? counts[type] : 0;
  72 }
  73
  74 /* requires the buffer lock to be held */
  75 static bool __evdev_is_filtered(struct evdev_client *client,
  76                                 unsigned int type,
  77                                 unsigned int code)
  78 {
  79         unsigned long *mask;
  80         size_t cnt;
  81
  82         /* EV_SYN and unknown codes are never filtered */
  83         if (type == EV_SYN || type >= EV_CNT)
  84                 return false;
  85
  86         /* first test whether the type is filtered */
  87         mask = client->evmasks[0];
  88         if (mask && !test_bit(type, mask))
  89                 return true;
  90
  91         /* unknown values are never filtered */
  92         cnt = evdev_get_mask_cnt(type);
  93         if (!cnt || code >= cnt)
  94                 return false;
  95
  96         mask = client->evmasks[type];
  97         return mask && !test_bit(code, mask);
  98 }
  99
 100 /* flush queued events of type @type, caller must hold client->buffer_lock */
 101 static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
 102 {
 103         unsigned int i, head, num;
 104         unsigned int mask = client->bufsize - 1;
 105         bool is_report;
 106         struct input_event *ev;
 107
 108         BUG_ON(type == EV_SYN);
 109
 110         head = client->tail;
 111         client->packet_head = client->tail;
 112
 113         /* init to 1 so a leading SYN_REPORT will not be dropped */
 114         num = 1;
 115
 116         for (i = client->tail; i != client->head; i = (i + 1) & mask) {
 117                 ev = &client->buffer[i];
 118                 is_report = ev->type == EV_SYN && ev->code == SYN_REPORT;
 119
 120                 if (ev->type == type) {
 121                         /* drop matched entry */
 122                         continue;
 123                 } else if (is_report && !num) {
 124                         /* drop empty SYN_REPORT groups */
 125                         continue;
 126                 } else if (head != i) {
 127                         /* move entry to fill the gap */
 128                         client->buffer[head] = *ev;
 129                 }
 130
 131                 num++;
 132                 head = (head + 1) & mask;
 133
 134                 if (is_report) {
 135                         num = 0;
 136                         client->packet_head = head;
 137                 }
 138         }
 139
 140         client->head = head;
 141 }
 142
 143 static void __evdev_queue_syn_dropped(struct evdev_client *client)
 144 {
 145         ktime_t *ev_time = input_get_timestamp(client->evdev->handle.dev);
 146         struct timespec64 ts = ktime_to_timespec64(ev_time[client->clk_type]);
 147         struct input_event ev;
 148
 149         ev.input_event_sec = ts.tv_sec;
 150         ev.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
 151         ev.type = EV_SYN;
 152         ev.code = SYN_DROPPED;
 153         ev.value = 0;
 154
 155         client->buffer[client->head++] = ev;
 156         client->head &= client->bufsize - 1;
 157
 158         if (unlikely(client->head == client->tail)) {
 159                 /* drop queue but keep our SYN_DROPPED event */
 160                 client->tail = (client->head - 1) & (client->bufsize - 1);
 161                 client->packet_head = client->tail;
 162         }
 163 }
 164
 165 static void evdev_queue_syn_dropped(struct evdev_client *client)
 166 {
 167         unsigned long flags;
 168
 169         spin_lock_irqsave(&client->buffer_lock, flags);
 170         __evdev_queue_syn_dropped(client);
 171         spin_unlock_irqrestore(&client->buffer_lock, flags);
 172 }
 173
 174 static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid)
 175 {
 176         unsigned long flags;
 177         enum input_clock_type clk_type;
 178
 179         switch (clkid) {
 180
 181         case CLOCK_REALTIME:
 182                 clk_type = INPUT_CLK_REAL;
 183                 break;
 184         case CLOCK_MONOTONIC:
 185                 clk_type = INPUT_CLK_MONO;
 186                 break;
 187         case CLOCK_BOOTTIME:
 188                 clk_type = INPUT_CLK_BOOT;
 189                 break;
 190         default:
 191                 return -EINVAL;
 192         }
 193
 194         if (client->clk_type != clk_type) {
 195                 client->clk_type = clk_type;
 196
 197                 /*
 198                  * Flush pending events and queue SYN_DROPPED event,
 199                  * but only if the queue is not empty.
 200                  */
 201                 spin_lock_irqsave(&client->buffer_lock, flags);
 202
 203                 if (client->head != client->tail) {
 204                         client->packet_head = client->head = client->tail;
 205                         __evdev_queue_syn_dropped(client);
 206                 }
 207
 208                 spin_unlock_irqrestore(&client->buffer_lock, flags);
 209         }
 210
 211         return 0;
 212 }
 213
 214 static void __pass_event(struct evdev_client *client,
 215                          const struct input_event *event)
 216 {
 217         client->buffer[client->head++] = *event;
 218         client->head &= client->bufsize - 1;
 219
 220         if (unlikely(client->head == client->tail)) {
 221                 /*
 222                  * This effectively "drops" all unconsumed events, leaving
 223                  * EV_SYN/SYN_DROPPED plus the newest event in the queue.
 224                  */
 225                 client->tail = (client->head - 2) & (client->bufsize - 1);
 226
 227                 client->buffer[client->tail] = (struct input_event) {
 228                         .input_event_sec = event->input_event_sec,
 229                         .input_event_usec = event->input_event_usec,
 230                         .type = EV_SYN,
 231                         .code = SYN_DROPPED,
 232                         .value = 0,
 233                 };
 234
 235                 client->packet_head = client->tail;
 236         }
 237
 238         if (event->type == EV_SYN && event->code == SYN_REPORT) {
 239                 client->packet_head = client->head;
 240                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
 241         }
 242 }
 243
 244 static void evdev_pass_values(struct evdev_client *client,
 245                         const struct input_value *vals, unsigned int count,
 246                         ktime_t *ev_time)
 247 {
 248         struct evdev *evdev = client->evdev;
 249         const struct input_value *v;
 250         struct input_event event;
 251         struct timespec64 ts;
 252         bool wakeup = false;
 253
 254         if (client->revoked)
 255                 return;
 256
 257         ts = ktime_to_timespec64(ev_time[client->clk_type]);
 258         event.input_event_sec = ts.tv_sec;
 259         event.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
 260
 261         /* Interrupts are disabled, just acquire the lock. */
 262         spin_lock(&client->buffer_lock);
 263
 264         for (v = vals; v != vals + count; v++) {
 265                 if (__evdev_is_filtered(client, v->type, v->code))
 266                         continue;
 267
 268                 if (v->type == EV_SYN && v->code == SYN_REPORT) {
 269                         /* drop empty SYN_REPORT */
 270                         if (client->packet_head == client->head)
 271                                 continue;
 272
 273                         wakeup = true;
 274                 }
 275
 276                 event.type = v->type;
 277                 event.code = v->code;
 278                 event.value = v->value;
 279                 __pass_event(client, &event);
 280         }
 281
 282         spin_unlock(&client->buffer_lock);
 283
 284         if (wakeup)
 285                 wake_up_interruptible(&evdev->wait);
 286 }
 287
 288 /*
 289  * Pass incoming events to all connected clients.
 290  */
 291 static void evdev_events(struct input_handle *handle,
 292                          const struct input_value *vals, unsigned int count)
 293 {
 294         struct evdev *evdev = handle->private;
 295         struct evdev_client *client;
 296         ktime_t *ev_time = input_get_timestamp(handle->dev);
 297
 298         rcu_read_lock();
 299
 300         client = rcu_dereference(evdev->grab);
 301
 302         if (client)
 303                 evdev_pass_values(client, vals, count, ev_time);
 304         else
 305                 list_for_each_entry_rcu(client, &evdev->client_list, node)
 306                         evdev_pass_values(client, vals, count, ev_time);
 307
 308         rcu_read_unlock();
 309 }
 310
 311 /*
 312  * Pass incoming event to all connected clients.
 313  */
 314 static void evdev_event(struct input_handle *handle,
 315                         unsigned int type, unsigned int code, int value)
 316 {
 317         struct input_value vals[] = { { type, code, value } };
 318
 319         evdev_events(handle, vals, 1);
 320 }
 321
 322 static int evdev_fasync(int fd, struct file *file, int on)
 323 {
 324         struct evdev_client *client = file->private_data;
 325
 326         return fasync_helper(fd, file, on, &client->fasync);
 327 }
 328
 329 static int evdev_flush(struct file *file, fl_owner_t id)
 330 {
 331         struct evdev_client *client = file->private_data;
 332         struct evdev *evdev = client->evdev;
 333
 334         mutex_lock(&evdev->mutex);
 335
 336         if (evdev->exist && !client->revoked)
 337                 input_flush_device(&evdev->handle, file);
 338
 339         mutex_unlock(&evdev->mutex);
 340         return 0;
 341 }
 342
 343 static void evdev_free(struct device *dev)
 344 {
 345         struct evdev *evdev = container_of(dev, struct evdev, dev);
 346
 347         input_put_device(evdev->handle.dev);
 348         kfree(evdev);
 349 }
 350
 351 /*
 352  * Grabs an event device (along with underlying input device).
 353  * This function is called with evdev->mutex taken.
 354  */
 355 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 356 {
 357         int error;
 358
 359         if (evdev->grab)
 360                 return -EBUSY;
 361
 362         error = input_grab_device(&evdev->handle);
 363         if (error)
 364                 return error;
 365
 366         rcu_assign_pointer(evdev->grab, client);
 367
 368         return 0;
 369 }
 370
 371 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 372 {
 373         struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
 374                                         lockdep_is_held(&evdev->mutex));
 375
 376         if (grab != client)
 377                 return  -EINVAL;
 378
 379         rcu_assign_pointer(evdev->grab, NULL);
 380         synchronize_rcu();
 381         input_release_device(&evdev->handle);
 382
 383         return 0;
 384 }
 385
 386 static void evdev_attach_client(struct evdev *evdev,
 387                                 struct evdev_client *client)
 388 {
 389         spin_lock(&evdev->client_lock);
 390         list_add_tail_rcu(&client->node, &evdev->client_list);
 391         spin_unlock(&evdev->client_lock);
 392 }
 393
 394 static void evdev_detach_client(struct evdev *evdev,
 395                                 struct evdev_client *client)
 396 {
 397         spin_lock(&evdev->client_lock);
 398         list_del_rcu(&client->node);
 399         spin_unlock(&evdev->client_lock);
 400         synchronize_rcu();
 401 }
 402
 403 static int evdev_open_device(struct evdev *evdev)
 404 {
 405         int retval;
 406
 407         retval = mutex_lock_interruptible(&evdev->mutex);
 408         if (retval)
 409                 return retval;
 410
 411         if (!evdev->exist)
 412                 retval = -ENODEV;
 413         else if (!evdev->open++) {
 414                 retval = input_open_device(&evdev->handle);
 415                 if (retval)
 416                         evdev->open--;
 417         }
 418
 419         mutex_unlock(&evdev->mutex);
 420         return retval;
 421 }
 422
 423 static void evdev_close_device(struct evdev *evdev)
 424 {
 425         mutex_lock(&evdev->mutex);
 426
 427         if (evdev->exist && !--evdev->open)
 428                 input_close_device(&evdev->handle);
 429
 430         mutex_unlock(&evdev->mutex);
 431 }
 432
 433 /*
 434  * Wake up users waiting for IO so they can disconnect from
 435  * dead device.
 436  */
 437 static void evdev_hangup(struct evdev *evdev)
 438 {
 439         struct evdev_client *client;
 440
 441         spin_lock(&evdev->client_lock);
 442         list_for_each_entry(client, &evdev->client_list, node)
 443                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 444         spin_unlock(&evdev->client_lock);
 445
 446         wake_up_interruptible(&evdev->wait);
 447 }
 448
 449 static int evdev_release(struct inode *inode, struct file *file)
 450 {
 451         struct evdev_client *client = file->private_data;
 452         struct evdev *evdev = client->evdev;
 453         unsigned int i;
 454
 455         mutex_lock(&evdev->mutex);
 456         evdev_ungrab(evdev, client);
 457         mutex_unlock(&evdev->mutex);
 458
 459         evdev_detach_client(evdev, client);
 460
 461         for (i = 0; i < EV_CNT; ++i)
 462                 bitmap_free(client->evmasks[i]);
 463
 464         kvfree(client);
 465
 466         evdev_close_device(evdev);
 467
 468         return 0;
 469 }
 470
 471 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 472 {
 473         unsigned int n_events =
 474                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 475                     EVDEV_MIN_BUFFER_SIZE);
 476
 477         return roundup_pow_of_two(n_events);
 478 }
 479
 480 static int evdev_open(struct inode *inode, struct file *file)
 481 {
 482         struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
 483         unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 484         struct evdev_client *client;
 485         int error;
 486
 487         client = kzalloc(struct_size(client, buffer, bufsize),
 488                          GFP_KERNEL | __GFP_NOWARN);
 489         if (!client)
 490                 client = vzalloc(struct_size(client, buffer, bufsize));
 491         if (!client)
 492                 return -ENOMEM;
 493
 494         client->bufsize = bufsize;
 495         spin_lock_init(&client->buffer_lock);
 496         client->evdev = evdev;
 497         evdev_attach_client(evdev, client);
 498
 499         error = evdev_open_device(evdev);
 500         if (error)
 501                 goto err_free_client;
 502
 503         file->private_data = client;
 504         stream_open(inode, file);
 505
 506         return 0;
 507
 508  err_free_client:
 509         evdev_detach_client(evdev, client);
 510         kvfree(client);
 511         return error;
 512 }
 513
 514 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 515                            size_t count, loff_t *ppos)
 516 {
 517         struct evdev_client *client = file->private_data;
 518         struct evdev *evdev = client->evdev;
 519         struct input_event event;
 520         int retval = 0;
 521
 522         if (count != 0 && count < input_event_size())
 523                 return -EINVAL;
 524
 525         retval = mutex_lock_interruptible(&evdev->mutex);
 526         if (retval)
 527                 return retval;
 528
 529         if (!evdev->exist || client->revoked) {
 530                 retval = -ENODEV;
 531                 goto out;
 532         }
 533
 534         while (retval + input_event_size() <= count) {
 535
 536                 if (input_event_from_user(buffer + retval, &event)) {
 537                         retval = -EFAULT;
 538                         goto out;
 539                 }
 540                 retval += input_event_size();
 541
 542                 input_inject_event(&evdev->handle,
 543                                    event.type, event.code, event.value);
 544                 cond_resched();
 545         }
 546
 547  out:
 548         mutex_unlock(&evdev->mutex);
 549         return retval;
 550 }
 551
 552 static int evdev_fetch_next_event(struct evdev_client *client,
 553                                   struct input_event *event)
 554 {
 555         int have_event;
 556
 557         spin_lock_irq(&client->buffer_lock);
 558
 559         have_event = client->packet_head != client->tail;
 560         if (have_event) {
 561                 *event = client->buffer[client->tail++];
 562                 client->tail &= client->bufsize - 1;
 563         }
 564
 565         spin_unlock_irq(&client->buffer_lock);
 566
 567         return have_event;
 568 }
 569
 570 static ssize_t evdev_read(struct file *file, char __user *buffer,
 571                           size_t count, loff_t *ppos)
 572 {
 573         struct evdev_client *client = file->private_data;
 574         struct evdev *evdev = client->evdev;
 575         struct input_event event;
 576         size_t read = 0;
 577         int error;
 578
 579         if (count != 0 && count < input_event_size())
 580                 return -EINVAL;
 581
 582         for (;;) {
 583                 if (!evdev->exist || client->revoked)
 584                         return -ENODEV;
 585
 586                 if (client->packet_head == client->tail &&
 587                     (file->f_flags & O_NONBLOCK))
 588                         return -EAGAIN;
 589
 590                 /*
 591                  * count == 0 is special - no IO is done but we check
 592                  * for error conditions (see above).
 593                  */
 594                 if (count == 0)
 595                         break;
 596
 597                 while (read + input_event_size() <= count &&
 598                        evdev_fetch_next_event(client, &event)) {
 599
 600                         if (input_event_to_user(buffer + read, &event))
 601                                 return -EFAULT;
 602
 603                         read += input_event_size();
 604                 }
 605
 606                 if (read)
 607                         break;
 608
 609                 if (!(file->f_flags & O_NONBLOCK)) {
 610                         error = wait_event_interruptible(evdev->wait,
 611                                         client->packet_head != client->tail ||
 612                                         !evdev->exist || client->revoked);
 613                         if (error)
 614                                 return error;
 615                 }
 616         }
 617
 618         return read;
 619 }
 620
 621 /* No kernel lock - fine */
 622 static __poll_t evdev_poll(struct file *file, poll_table *wait)
 623 {
 624         struct evdev_client *client = file->private_data;
 625         struct evdev *evdev = client->evdev;
 626         __poll_t mask;
 627
 628         poll_wait(file, &evdev->wait, wait);
 629
 630         if (evdev->exist && !client->revoked)
 631                 mask = EPOLLOUT | EPOLLWRNORM;
 632         else
 633                 mask = EPOLLHUP | EPOLLERR;
 634
 635         if (client->packet_head != client->tail)
 636                 mask |= EPOLLIN | EPOLLRDNORM;
 637
 638         return mask;
 639 }
 640
 641 #ifdef CONFIG_COMPAT
 642
 643 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 644 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 645
 646 #ifdef __BIG_ENDIAN
 647 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 648                         unsigned int maxlen, void __user *p, int compat)
 649 {
 650         int len, i;
 651
 652         if (compat) {
 653                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 654                 if (len > maxlen)
 655                         len = maxlen;
 656
 657                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 658                         if (copy_to_user((compat_long_t __user *) p + i,
 659                                          (compat_long_t *) bits +
 660                                                 i + 1 - ((i % 2) << 1),
 661                                          sizeof(compat_long_t)))
 662                                 return -EFAULT;
 663         } else {
 664                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 665                 if (len > maxlen)
 666                         len = maxlen;
 667
 668                 if (copy_to_user(p, bits, len))
 669                         return -EFAULT;
 670         }
 671
 672         return len;
 673 }
 674
 675 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
 676                           unsigned int maxlen, const void __user *p, int compat)
 677 {
 678         int len, i;
 679
 680         if (compat) {
 681                 if (maxlen % sizeof(compat_long_t))
 682                         return -EINVAL;
 683
 684                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 685                 if (len > maxlen)
 686                         len = maxlen;
 687
 688                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 689                         if (copy_from_user((compat_long_t *) bits +
 690                                                 i + 1 - ((i % 2) << 1),
 691                                            (compat_long_t __user *) p + i,
 692                                            sizeof(compat_long_t)))
 693                                 return -EFAULT;
 694                 if (i % 2)
 695                         *((compat_long_t *) bits + i - 1) = 0;
 696
 697         } else {
 698                 if (maxlen % sizeof(long))
 699                         return -EINVAL;
 700
 701                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 702                 if (len > maxlen)
 703                         len = maxlen;
 704
 705                 if (copy_from_user(bits, p, len))
 706                         return -EFAULT;
 707         }
 708
 709         return len;
 710 }
 711
 712 #else
 713
 714 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 715                         unsigned int maxlen, void __user *p, int compat)
 716 {
 717         int len = compat ?
 718                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 719                         BITS_TO_LONGS(maxbit) * sizeof(long);
 720
 721         if (len > maxlen)
 722                 len = maxlen;
 723
 724         return copy_to_user(p, bits, len) ? -EFAULT : len;
 725 }
 726
 727 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
 728                           unsigned int maxlen, const void __user *p, int compat)
 729 {
 730         size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long);
 731         int len;
 732
 733         if (maxlen % chunk_size)
 734                 return -EINVAL;
 735
 736         len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);
 737         len *= chunk_size;
 738         if (len > maxlen)
 739                 len = maxlen;
 740
 741         return copy_from_user(bits, p, len) ? -EFAULT : len;
 742 }
 743
 744 #endif /* __BIG_ENDIAN */
 745
 746 #else
 747
 748 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 749                         unsigned int maxlen, void __user *p, int compat)
 750 {
 751         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 752
 753         if (len > maxlen)
 754                 len = maxlen;
 755
 756         return copy_to_user(p, bits, len) ? -EFAULT : len;
 757 }
 758
 759 static int bits_from_user(unsigned long *bits, unsigned int maxbit,
 760                           unsigned int maxlen, const void __user *p, int compat)
 761 {
 762         int len;
 763
 764         if (maxlen % sizeof(long))
 765                 return -EINVAL;
 766
 767         len = BITS_TO_LONGS(maxbit) * sizeof(long);
 768         if (len > maxlen)
 769                 len = maxlen;
 770
 771         return copy_from_user(bits, p, len) ? -EFAULT : len;
 772 }
 773
 774 #endif /* CONFIG_COMPAT */
 775
 776 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 777 {
 778         int len;
 779
 780         if (!str)
 781                 return -ENOENT;
 782
 783         len = strlen(str) + 1;
 784         if (len > maxlen)
 785                 len = maxlen;
 786
 787         return copy_to_user(p, str, len) ? -EFAULT : len;
 788 }
 789
 790 static int handle_eviocgbit(struct input_dev *dev,
 791                             unsigned int type, unsigned int size,
 792                             void __user *p, int compat_mode)
 793 {
 794         unsigned long *bits;
 795         int len;
 796
 797         switch (type) {
 798
 799         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 800         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 801         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 802         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 803         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 804         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 805         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 806         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 807         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 808         default: return -EINVAL;
 809         }
 810
 811         return bits_to_user(bits, len, size, p, compat_mode);
 812 }
 813
 814 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
 815 {
 816         struct input_keymap_entry ke = {
 817                 .len    = sizeof(unsigned int),
 818                 .flags  = 0,
 819         };
 820         int __user *ip = (int __user *)p;
 821         int error;
 822
 823         /* legacy case */
 824         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 825                 return -EFAULT;
 826
 827         error = input_get_keycode(dev, &ke);
 828         if (error)
 829                 return error;
 830
 831         if (put_user(ke.keycode, ip + 1))
 832                 return -EFAULT;
 833
 834         return 0;
 835 }
 836
 837 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
 838 {
 839         struct input_keymap_entry ke;
 840         int error;
 841
 842         if (copy_from_user(&ke, p, sizeof(ke)))
 843                 return -EFAULT;
 844
 845         error = input_get_keycode(dev, &ke);
 846         if (error)
 847                 return error;
 848
 849         if (copy_to_user(p, &ke, sizeof(ke)))
 850                 return -EFAULT;
 851
 852         return 0;
 853 }
 854
 855 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
 856 {
 857         struct input_keymap_entry ke = {
 858                 .len    = sizeof(unsigned int),
 859                 .flags  = 0,
 860         };
 861         int __user *ip = (int __user *)p;
 862
 863         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 864                 return -EFAULT;
 865
 866         if (get_user(ke.keycode, ip + 1))
 867                 return -EFAULT;
 868
 869         return input_set_keycode(dev, &ke);
 870 }
 871
 872 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
 873 {
 874         struct input_keymap_entry ke;
 875
 876         if (copy_from_user(&ke, p, sizeof(ke)))
 877                 return -EFAULT;
 878
 879         if (ke.len > sizeof(ke.scancode))
 880                 return -EINVAL;
 881
 882         return input_set_keycode(dev, &ke);
 883 }
 884
 885 /*
 886  * If we transfer state to the user, we should flush all pending events
 887  * of the same type from the client's queue. Otherwise, they might end up
 888  * with duplicate events, which can screw up client's state tracking.
 889  * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
 890  * event so user-space will notice missing events.
 891  *
 892  * LOCKING:
 893  * We need to take event_lock before buffer_lock to avoid dead-locks. But we
 894  * need the even_lock only to guarantee consistent state. We can safely release
 895  * it while flushing the queue. This allows input-core to handle filters while
 896  * we flush the queue.
 897  */
 898 static int evdev_handle_get_val(struct evdev_client *client,
 899                                 struct input_dev *dev, unsigned int type,
 900                                 unsigned long *bits, unsigned int maxbit,
 901                                 unsigned int maxlen, void __user *p,
 902                                 int compat)
 903 {
 904         int ret;
 905         unsigned long *mem;
 906
 907         mem = bitmap_alloc(maxbit, GFP_KERNEL);
 908         if (!mem)
 909                 return -ENOMEM;
 910
 911         spin_lock_irq(&dev->event_lock);
 912         spin_lock(&client->buffer_lock);
 913
 914         bitmap_copy(mem, bits, maxbit);
 915
 916         spin_unlock(&dev->event_lock);
 917
 918         __evdev_flush_queue(client, type);
 919
 920         spin_unlock_irq(&client->buffer_lock);
 921
 922         ret = bits_to_user(mem, maxbit, maxlen, p, compat);
 923         if (ret < 0)
 924                 evdev_queue_syn_dropped(client);
 925
 926         bitmap_free(mem);
 927
 928         return ret;
 929 }
 930
 931 static int evdev_handle_mt_request(struct input_dev *dev,
 932                                    unsigned int size,
 933                                    int __user *ip)
 934 {
 935         const struct input_mt *mt = dev->mt;
 936         unsigned int code;
 937         int max_slots;
 938         int i;
 939
 940         if (get_user(code, &ip[0]))
 941                 return -EFAULT;
 942         if (!mt || !input_is_mt_value(code))
 943                 return -EINVAL;
 944
 945         max_slots = (size - sizeof(__u32)) / sizeof(__s32);
 946         for (i = 0; i < mt->num_slots && i < max_slots; i++) {
 947                 int value = input_mt_get_value(&mt->slots[i], code);
 948                 if (put_user(value, &ip[1 + i]))
 949                         return -EFAULT;
 950         }
 951
 952         return 0;
 953 }
 954
 955 static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
 956                         struct file *file)
 957 {
 958         client->revoked = true;
 959         evdev_ungrab(evdev, client);
 960         input_flush_device(&evdev->handle, file);
 961         wake_up_interruptible(&evdev->wait);
 962
 963         return 0;
 964 }
 965
 966 /* must be called with evdev-mutex held */
 967 static int evdev_set_mask(struct evdev_client *client,
 968                           unsigned int type,
 969                           const void __user *codes,
 970                           u32 codes_size,
 971                           int compat)
 972 {
 973         unsigned long flags, *mask, *oldmask;
 974         size_t cnt;
 975         int error;
 976
 977         /* we allow unknown types and 'codes_size > size' for forward-compat */
 978         cnt = evdev_get_mask_cnt(type);
 979         if (!cnt)
 980                 return 0;
 981
 982         mask = bitmap_zalloc(cnt, GFP_KERNEL);
 983         if (!mask)
 984                 return -ENOMEM;
 985
 986         error = bits_from_user(mask, cnt - 1, codes_size, codes, compat);
 987         if (error < 0) {
 988                 bitmap_free(mask);
 989                 return error;
 990         }
 991
 992         spin_lock_irqsave(&client->buffer_lock, flags);
 993         oldmask = client->evmasks[type];
 994         client->evmasks[type] = mask;
 995         spin_unlock_irqrestore(&client->buffer_lock, flags);
 996
 997         bitmap_free(oldmask);
 998
 999         return 0;
1000 }
1001
1002 /* must be called with evdev-mutex held */
1003 static int evdev_get_mask(struct evdev_client *client,
1004                           unsigned int type,
1005                           void __user *codes,
1006                           u32 codes_size,
1007                           int compat)
1008 {
1009         unsigned long *mask;
1010         size_t cnt, size, xfer_size;
1011         int i;
1012         int error;
1013
1014         /* we allow unknown types and 'codes_size > size' for forward-compat */
1015         cnt = evdev_get_mask_cnt(type);
1016         size = sizeof(unsigned long) * BITS_TO_LONGS(cnt);
1017         xfer_size = min_t(size_t, codes_size, size);
1018
1019         if (cnt > 0) {
1020                 mask = client->evmasks[type];
1021                 if (mask) {
1022                         error = bits_to_user(mask, cnt - 1,
1023                                              xfer_size, codes, compat);
1024                         if (error < 0)
1025                                 return error;
1026                 } else {
1027                         /* fake mask with all bits set */
1028                         for (i = 0; i < xfer_size; i++)
1029                                 if (put_user(0xffU, (u8 __user *)codes + i))
1030                                         return -EFAULT;
1031                 }
1032         }
1033
1034         if (xfer_size < codes_size)
1035                 if (clear_user(codes + xfer_size, codes_size - xfer_size))
1036                         return -EFAULT;
1037
1038         return 0;
1039 }
1040
1041 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
1042                            void __user *p, int compat_mode)
1043 {
1044         struct evdev_client *client = file->private_data;
1045         struct evdev *evdev = client->evdev;
1046         struct input_dev *dev = evdev->handle.dev;
1047         struct input_absinfo abs;
1048         struct input_mask mask;
1049         struct ff_effect effect;
1050         int __user *ip = (int __user *)p;
1051         unsigned int i, t, u, v;
1052         unsigned int size;
1053         int error;
1054
1055         /* First we check for fixed-length commands */
1056         switch (cmd) {
1057
1058         case EVIOCGVERSION:
1059                 return put_user(EV_VERSION, ip);
1060
1061         case EVIOCGID:
1062                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
1063                         return -EFAULT;
1064                 return 0;
1065
1066         case EVIOCGREP:
1067                 if (!test_bit(EV_REP, dev->evbit))
1068                         return -ENOSYS;
1069                 if (put_user(dev->rep[REP_DELAY], ip))
1070                         return -EFAULT;
1071                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
1072                         return -EFAULT;
1073                 return 0;
1074
1075         case EVIOCSREP:
1076                 if (!test_bit(EV_REP, dev->evbit))
1077                         return -ENOSYS;
1078                 if (get_user(u, ip))
1079                         return -EFAULT;
1080                 if (get_user(v, ip + 1))
1081                         return -EFAULT;
1082
1083                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
1084                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
1085
1086                 return 0;
1087
1088         case EVIOCRMFF:
1089                 return input_ff_erase(dev, (int)(unsigned long) p, file);
1090
1091         case EVIOCGEFFECTS:
1092                 i = test_bit(EV_FF, dev->evbit) ?
1093                                 dev->ff->max_effects : 0;
1094                 if (put_user(i, ip))
1095                         return -EFAULT;
1096                 return 0;
1097
1098         case EVIOCGRAB:
1099                 if (p)
1100                         return evdev_grab(evdev, client);
1101                 else
1102                         return evdev_ungrab(evdev, client);
1103
1104         case EVIOCREVOKE:
1105                 if (p)
1106                         return -EINVAL;
1107                 else
1108                         return evdev_revoke(evdev, client, file);
1109
1110         case EVIOCGMASK: {
1111                 void __user *codes_ptr;
1112
1113                 if (copy_from_user(&mask, p, sizeof(mask)))
1114                         return -EFAULT;
1115
1116                 codes_ptr = (void __user *)(unsigned long)mask.codes_ptr;
1117                 return evdev_get_mask(client,
1118                                       mask.type, codes_ptr, mask.codes_size,
1119                                       compat_mode);
1120         }
1121
1122         case EVIOCSMASK: {
1123                 const void __user *codes_ptr;
1124
1125                 if (copy_from_user(&mask, p, sizeof(mask)))
1126                         return -EFAULT;
1127
1128                 codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr;
1129                 return evdev_set_mask(client,
1130                                       mask.type, codes_ptr, mask.codes_size,
1131                                       compat_mode);
1132         }
1133
1134         case EVIOCSCLOCKID:
1135                 if (copy_from_user(&i, p, sizeof(unsigned int)))
1136                         return -EFAULT;
1137
1138                 return evdev_set_clk_type(client, i);
1139
1140         case EVIOCGKEYCODE:
1141                 return evdev_handle_get_keycode(dev, p);
1142
1143         case EVIOCSKEYCODE:
1144                 return evdev_handle_set_keycode(dev, p);
1145
1146         case EVIOCGKEYCODE_V2:
1147                 return evdev_handle_get_keycode_v2(dev, p);
1148
1149         case EVIOCSKEYCODE_V2:
1150                 return evdev_handle_set_keycode_v2(dev, p);
1151         }
1152
1153         size = _IOC_SIZE(cmd);
1154
1155         /* Now check variable-length commands */
1156 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
1157         switch (EVIOC_MASK_SIZE(cmd)) {
1158
1159         case EVIOCGPROP(0):
1160                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
1161                                     size, p, compat_mode);
1162
1163         case EVIOCGMTSLOTS(0):
1164                 return evdev_handle_mt_request(dev, size, ip);
1165
1166         case EVIOCGKEY(0):
1167                 return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
1168                                             KEY_MAX, size, p, compat_mode);
1169
1170         case EVIOCGLED(0):
1171                 return evdev_handle_get_val(client, dev, EV_LED, dev->led,
1172                                             LED_MAX, size, p, compat_mode);
1173
1174         case EVIOCGSND(0):
1175                 return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
1176                                             SND_MAX, size, p, compat_mode);
1177
1178         case EVIOCGSW(0):
1179                 return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
1180                                             SW_MAX, size, p, compat_mode);
1181
1182         case EVIOCGNAME(0):
1183                 return str_to_user(dev->name, size, p);
1184
1185         case EVIOCGPHYS(0):
1186                 return str_to_user(dev->phys, size, p);
1187
1188         case EVIOCGUNIQ(0):
1189                 return str_to_user(dev->uniq, size, p);
1190
1191         case EVIOC_MASK_SIZE(EVIOCSFF):
1192                 if (input_ff_effect_from_user(p, size, &effect))
1193                         return -EFAULT;
1194
1195                 error = input_ff_upload(dev, &effect, file);
1196                 if (error)
1197                         return error;
1198
1199                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
1200                         return -EFAULT;
1201
1202                 return 0;
1203         }
1204
1205         /* Multi-number variable-length handlers */
1206         if (_IOC_TYPE(cmd) != 'E')
1207                 return -EINVAL;
1208
1209         if (_IOC_DIR(cmd) == _IOC_READ) {
1210
1211                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
1212                         return handle_eviocgbit(dev,
1213                                                 _IOC_NR(cmd) & EV_MAX, size,
1214                                                 p, compat_mode);
1215
1216                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1217
1218                         if (!dev->absinfo)
1219                                 return -EINVAL;
1220
1221                         t = _IOC_NR(cmd) & ABS_MAX;
1222                         abs = dev->absinfo[t];
1223
1224                         if (copy_to_user(p, &abs, min_t(size_t,
1225                                         size, sizeof(struct input_absinfo))))
1226                                 return -EFAULT;
1227
1228                         return 0;
1229                 }
1230         }
1231
1232         if (_IOC_DIR(cmd) == _IOC_WRITE) {
1233
1234                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1235
1236                         if (!dev->absinfo)
1237                                 return -EINVAL;
1238
1239                         t = _IOC_NR(cmd) & ABS_MAX;
1240
1241                         if (copy_from_user(&abs, p, min_t(size_t,
1242                                         size, sizeof(struct input_absinfo))))
1243                                 return -EFAULT;
1244
1245                         if (size < sizeof(struct input_absinfo))
1246                                 abs.resolution = 0;
1247
1248                         /* We can't change number of reserved MT slots */
1249                         if (t == ABS_MT_SLOT)
1250                                 return -EINVAL;
1251
1252                         /*
1253                          * Take event lock to ensure that we are not
1254                          * changing device parameters in the middle
1255                          * of event.
1256                          */
1257                         spin_lock_irq(&dev->event_lock);
1258                         dev->absinfo[t] = abs;
1259                         spin_unlock_irq(&dev->event_lock);
1260
1261                         return 0;
1262                 }
1263         }
1264
1265         return -EINVAL;
1266 }
1267
1268 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1269                                 void __user *p, int compat_mode)
1270 {
1271         struct evdev_client *client = file->private_data;
1272         struct evdev *evdev = client->evdev;
1273         int retval;
1274
1275         retval = mutex_lock_interruptible(&evdev->mutex);
1276         if (retval)
1277                 return retval;
1278
1279         if (!evdev->exist || client->revoked) {
1280                 retval = -ENODEV;
1281                 goto out;
1282         }
1283
1284         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1285
1286  out:
1287         mutex_unlock(&evdev->mutex);
1288         return retval;
1289 }
1290
1291 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1292 {
1293         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1294 }
1295
1296 #ifdef CONFIG_COMPAT
1297 static long evdev_ioctl_compat(struct file *file,
1298                                 unsigned int cmd, unsigned long arg)
1299 {
1300         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1301 }
1302 #endif
1303
1304 static const struct file_operations evdev_fops = {
1305         .owner          = THIS_MODULE,
1306         .read           = evdev_read,
1307         .write          = evdev_write,
1308         .poll           = evdev_poll,
1309         .open           = evdev_open,
1310         .release        = evdev_release,
1311         .unlocked_ioctl = evdev_ioctl,
1312 #ifdef CONFIG_COMPAT
1313         .compat_ioctl   = evdev_ioctl_compat,
1314 #endif
1315         .fasync         = evdev_fasync,
1316         .flush          = evdev_flush,
1317         .llseek         = no_llseek,
1318 };
1319
1320 /*
1321  * Mark device non-existent. This disables writes, ioctls and
1322  * prevents new users from opening the device. Already posted
1323  * blocking reads will stay, however new ones will fail.
1324  */
1325 static void evdev_mark_dead(struct evdev *evdev)
1326 {
1327         mutex_lock(&evdev->mutex);
1328         evdev->exist = false;
1329         mutex_unlock(&evdev->mutex);
1330 }
1331
1332 static void evdev_cleanup(struct evdev *evdev)
1333 {
1334         struct input_handle *handle = &evdev->handle;
1335
1336         evdev_mark_dead(evdev);
1337         evdev_hangup(evdev);
1338
1339         /* evdev is marked dead so no one else accesses evdev->open */
1340         if (evdev->open) {
1341                 input_flush_device(handle, NULL);
1342                 input_close_device(handle);
1343         }
1344 }
1345
1346 /*
1347  * Create new evdev device. Note that input core serializes calls
1348  * to connect and disconnect.
1349  */
1350 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1351                          const struct input_device_id *id)
1352 {
1353         struct evdev *evdev;
1354         int minor;
1355         int dev_no;
1356         int error;
1357
1358         minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1359         if (minor < 0) {
1360                 error = minor;
1361                 pr_err("failed to reserve new minor: %d\n", error);
1362                 return error;
1363         }
1364
1365         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1366         if (!evdev) {
1367                 error = -ENOMEM;
1368                 goto err_free_minor;
1369         }
1370
1371         INIT_LIST_HEAD(&evdev->client_list);
1372         spin_lock_init(&evdev->client_lock);
1373         mutex_init(&evdev->mutex);
1374         init_waitqueue_head(&evdev->wait);
1375         evdev->exist = true;
1376
1377         dev_no = minor;
1378         /* Normalize device number if it falls into legacy range */
1379         if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1380                 dev_no -= EVDEV_MINOR_BASE;
1381         dev_set_name(&evdev->dev, "event%d", dev_no);
1382
1383         evdev->handle.dev = input_get_device(dev);
1384         evdev->handle.name = dev_name(&evdev->dev);
1385         evdev->handle.handler = handler;
1386         evdev->handle.private = evdev;
1387
1388         evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1389         evdev->dev.class = &input_class;
1390         evdev->dev.parent = &dev->dev;
1391         evdev->dev.release = evdev_free;
1392         device_initialize(&evdev->dev);
1393
1394         error = input_register_handle(&evdev->handle);
1395         if (error)
1396                 goto err_free_evdev;
1397
1398         cdev_init(&evdev->cdev, &evdev_fops);
1399
1400         error = cdev_device_add(&evdev->cdev, &evdev->dev);
1401         if (error)
1402                 goto err_cleanup_evdev;
1403
1404         return 0;
1405
1406  err_cleanup_evdev:
1407         evdev_cleanup(evdev);
1408         input_unregister_handle(&evdev->handle);
1409  err_free_evdev:
1410         put_device(&evdev->dev);
1411  err_free_minor:
1412         input_free_minor(minor);
1413         return error;
1414 }
1415
1416 static void evdev_disconnect(struct input_handle *handle)
1417 {
1418         struct evdev *evdev = handle->private;
1419
1420         cdev_device_del(&evdev->cdev, &evdev->dev);
1421         evdev_cleanup(evdev);
1422         input_free_minor(MINOR(evdev->dev.devt));
1423         input_unregister_handle(handle);
1424         put_device(&evdev->dev);
1425 }
1426
1427 static const struct input_device_id evdev_ids[] = {
1428         { .driver_info = 1 },   /* Matches all devices */
1429         { },                    /* Terminating zero entry */
1430 };
1431
1432 MODULE_DEVICE_TABLE(input, evdev_ids);
1433
1434 static struct input_handler evdev_handler = {
1435         .event          = evdev_event,
1436         .events         = evdev_events,
1437         .connect        = evdev_connect,
1438         .disconnect     = evdev_disconnect,
1439         .legacy_minors  = true,
1440         .minor          = EVDEV_MINOR_BASE,
1441         .name           = "evdev",
1442         .id_table       = evdev_ids,
1443 };
1444
1445 static int __init evdev_init(void)
1446 {
1447         return input_register_handler(&evdev_handler);
1448 }
1449
1450 static void __exit evdev_exit(void)
1451 {
1452         input_unregister_handler(&evdev_handler);
1453 }
1454
1455 module_init(evdev_init);
1456 module_exit(evdev_exit);
1457
1458 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1459 MODULE_DESCRIPTION("Input driver event char devices");
1460 MODULE_LICENSE("GPL");