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 <linux/wakelock.h>
  27 #include "input-compat.h"
  28
  29 struct evdev {
  30         int open;
  31         int minor;
  32         struct input_handle handle;
  33         wait_queue_head_t wait;
  34         struct evdev_client __rcu *grab;
  35         struct list_head client_list;
  36         spinlock_t client_lock; /* protects client_list */
  37         struct mutex mutex;
  38         struct device dev;
  39         bool exist;
  40 };
  41
  42 struct evdev_client {
  43         unsigned int head;
  44         unsigned int tail;
  45         unsigned int packet_head; /* [future] position of the first element of next packet */
  46         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  47         struct wake_lock wake_lock;
  48         char name[28];
  49         struct fasync_struct *fasync;
  50         struct evdev *evdev;
  51         struct list_head node;
  52         unsigned int bufsize;
  53         struct input_event buffer[];
  54 };
  55
  56 static struct evdev *evdev_table[EVDEV_MINORS];
  57 static DEFINE_MUTEX(evdev_table_mutex);
  58
  59 static void evdev_pass_event(struct evdev_client *client,
  60                              struct input_event *event)
  61 {
  62         /* Interrupts are disabled, just acquire the lock. */
  63         spin_lock(&client->buffer_lock);
  64
  65         wake_lock_timeout(&client->wake_lock, 5 * HZ);
  66         client->buffer[client->head++] = *event;
  67         client->head &= client->bufsize - 1;
  68
  69         if (unlikely(client->head == client->tail)) {
  70                 /*
  71                  * This effectively "drops" all unconsumed events, leaving
  72                  * EV_SYN/SYN_DROPPED plus the newest event in the queue.
  73                  */
  74                 client->tail = (client->head - 2) & (client->bufsize - 1);
  75
  76                 client->buffer[client->tail].time = event->time;
  77                 client->buffer[client->tail].type = EV_SYN;
  78                 client->buffer[client->tail].code = SYN_DROPPED;
  79                 client->buffer[client->tail].value = 0;
  80
  81                 client->packet_head = client->tail;
  82         }
  83
  84         if (event->type == EV_SYN && event->code == SYN_REPORT) {
  85                 client->packet_head = client->head;
  86                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
  87         }
  88
  89         spin_unlock(&client->buffer_lock);
  90 }
  91
  92 /*
  93  * Pass incoming event to all connected clients.
  94  */
  95 static void evdev_event(struct input_handle *handle,
  96                         unsigned int type, unsigned int code, int value)
  97 {
  98         struct evdev *evdev = handle->private;
  99         struct evdev_client *client;
 100         struct input_event event;
 101         struct timespec ts;
 102
 103         ktime_get_ts(&ts);
 104         event.time.tv_sec = ts.tv_sec;
 105         event.time.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
 106         event.type = type;
 107         event.code = code;
 108         event.value = value;
 109
 110         rcu_read_lock();
 111
 112         client = rcu_dereference(evdev->grab);
 113         if (client)
 114                 evdev_pass_event(client, &event);
 115         else
 116                 list_for_each_entry_rcu(client, &evdev->client_list, node)
 117                         evdev_pass_event(client, &event);
 118
 119         rcu_read_unlock();
 120
 121         if (type == EV_SYN && code == SYN_REPORT)
 122                 wake_up_interruptible(&evdev->wait);
 123 }
 124
 125 static int evdev_fasync(int fd, struct file *file, int on)
 126 {
 127         struct evdev_client *client = file->private_data;
 128
 129         return fasync_helper(fd, file, on, &client->fasync);
 130 }
 131
 132 static int evdev_flush(struct file *file, fl_owner_t id)
 133 {
 134         struct evdev_client *client = file->private_data;
 135         struct evdev *evdev = client->evdev;
 136         int retval;
 137
 138         retval = mutex_lock_interruptible(&evdev->mutex);
 139         if (retval)
 140                 return retval;
 141
 142         if (!evdev->exist)
 143                 retval = -ENODEV;
 144         else
 145                 retval = input_flush_device(&evdev->handle, file);
 146
 147         mutex_unlock(&evdev->mutex);
 148         return retval;
 149 }
 150
 151 static void evdev_free(struct device *dev)
 152 {
 153         struct evdev *evdev = container_of(dev, struct evdev, dev);
 154
 155         input_put_device(evdev->handle.dev);
 156         kfree(evdev);
 157 }
 158
 159 /*
 160  * Grabs an event device (along with underlying input device).
 161  * This function is called with evdev->mutex taken.
 162  */
 163 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 164 {
 165         int error;
 166
 167         if (evdev->grab)
 168                 return -EBUSY;
 169
 170         error = input_grab_device(&evdev->handle);
 171         if (error)
 172                 return error;
 173
 174         rcu_assign_pointer(evdev->grab, client);
 175
 176         return 0;
 177 }
 178
 179 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 180 {
 181         if (evdev->grab != client)
 182                 return  -EINVAL;
 183
 184         rcu_assign_pointer(evdev->grab, NULL);
 185         synchronize_rcu();
 186         input_release_device(&evdev->handle);
 187
 188         return 0;
 189 }
 190
 191 static void evdev_attach_client(struct evdev *evdev,
 192                                 struct evdev_client *client)
 193 {
 194         spin_lock(&evdev->client_lock);
 195         list_add_tail_rcu(&client->node, &evdev->client_list);
 196         spin_unlock(&evdev->client_lock);
 197 }
 198
 199 static void evdev_detach_client(struct evdev *evdev,
 200                                 struct evdev_client *client)
 201 {
 202         spin_lock(&evdev->client_lock);
 203         list_del_rcu(&client->node);
 204         spin_unlock(&evdev->client_lock);
 205         synchronize_rcu();
 206 }
 207
 208 static int evdev_open_device(struct evdev *evdev)
 209 {
 210         int retval;
 211
 212         retval = mutex_lock_interruptible(&evdev->mutex);
 213         if (retval)
 214                 return retval;
 215
 216         if (!evdev->exist)
 217                 retval = -ENODEV;
 218         else if (!evdev->open++) {
 219                 retval = input_open_device(&evdev->handle);
 220                 if (retval)
 221                         evdev->open--;
 222         }
 223
 224         mutex_unlock(&evdev->mutex);
 225         return retval;
 226 }
 227
 228 static void evdev_close_device(struct evdev *evdev)
 229 {
 230         mutex_lock(&evdev->mutex);
 231
 232         if (evdev->exist && !--evdev->open)
 233                 input_close_device(&evdev->handle);
 234
 235         mutex_unlock(&evdev->mutex);
 236 }
 237
 238 /*
 239  * Wake up users waiting for IO so they can disconnect from
 240  * dead device.
 241  */
 242 static void evdev_hangup(struct evdev *evdev)
 243 {
 244         struct evdev_client *client;
 245
 246         spin_lock(&evdev->client_lock);
 247         list_for_each_entry(client, &evdev->client_list, node)
 248                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 249         spin_unlock(&evdev->client_lock);
 250
 251         wake_up_interruptible(&evdev->wait);
 252 }
 253
 254 static int evdev_release(struct inode *inode, struct file *file)
 255 {
 256         struct evdev_client *client = file->private_data;
 257         struct evdev *evdev = client->evdev;
 258
 259         mutex_lock(&evdev->mutex);
 260         if (evdev->grab == client)
 261                 evdev_ungrab(evdev, client);
 262         mutex_unlock(&evdev->mutex);
 263
 264         evdev_detach_client(evdev, client);
 265         wake_lock_destroy(&client->wake_lock);
 266         kfree(client);
 267
 268         evdev_close_device(evdev);
 269         put_device(&evdev->dev);
 270
 271         return 0;
 272 }
 273
 274 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 275 {
 276         unsigned int n_events =
 277                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 278                     EVDEV_MIN_BUFFER_SIZE);
 279
 280         return roundup_pow_of_two(n_events);
 281 }
 282
 283 static int evdev_open(struct inode *inode, struct file *file)
 284 {
 285         struct evdev *evdev;
 286         struct evdev_client *client;
 287         int i = iminor(inode) - EVDEV_MINOR_BASE;
 288         unsigned int bufsize;
 289         int error;
 290
 291         if (i >= EVDEV_MINORS)
 292                 return -ENODEV;
 293
 294         error = mutex_lock_interruptible(&evdev_table_mutex);
 295         if (error)
 296                 return error;
 297         evdev = evdev_table[i];
 298         if (evdev)
 299                 get_device(&evdev->dev);
 300         mutex_unlock(&evdev_table_mutex);
 301
 302         if (!evdev)
 303                 return -ENODEV;
 304
 305         bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 306
 307         client = kzalloc(sizeof(struct evdev_client) +
 308                                 bufsize * sizeof(struct input_event),
 309                          GFP_KERNEL);
 310         if (!client) {
 311                 error = -ENOMEM;
 312                 goto err_put_evdev;
 313         }
 314
 315         client->bufsize = bufsize;
 316         spin_lock_init(&client->buffer_lock);
 317         snprintf(client->name, sizeof(client->name), "%s-%d",
 318                         dev_name(&evdev->dev), task_tgid_vnr(current));
 319         wake_lock_init(&client->wake_lock, WAKE_LOCK_SUSPEND, client->name);
 320         client->evdev = evdev;
 321         evdev_attach_client(evdev, client);
 322
 323         error = evdev_open_device(evdev);
 324         if (error)
 325                 goto err_free_client;
 326
 327         file->private_data = client;
 328         nonseekable_open(inode, file);
 329
 330         return 0;
 331
 332  err_free_client:
 333         evdev_detach_client(evdev, client);
 334         wake_lock_destroy(&client->wake_lock);
 335         kfree(client);
 336  err_put_evdev:
 337         put_device(&evdev->dev);
 338         return error;
 339 }
 340
 341 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 342                            size_t count, loff_t *ppos)
 343 {
 344         struct evdev_client *client = file->private_data;
 345         struct evdev *evdev = client->evdev;
 346         struct input_event event;
 347         int retval;
 348
 349         if (count < input_event_size())
 350                 return -EINVAL;
 351
 352         retval = mutex_lock_interruptible(&evdev->mutex);
 353         if (retval)
 354                 return retval;
 355
 356         if (!evdev->exist) {
 357                 retval = -ENODEV;
 358                 goto out;
 359         }
 360
 361         do {
 362                 if (input_event_from_user(buffer + retval, &event)) {
 363                         retval = -EFAULT;
 364                         goto out;
 365                 }
 366                 retval += input_event_size();
 367
 368                 input_inject_event(&evdev->handle,
 369                                    event.type, event.code, event.value);
 370         } while (retval + input_event_size() <= count);
 371
 372  out:
 373         mutex_unlock(&evdev->mutex);
 374         return retval;
 375 }
 376
 377 static int evdev_fetch_next_event(struct evdev_client *client,
 378                                   struct input_event *event)
 379 {
 380         int have_event;
 381
 382         spin_lock_irq(&client->buffer_lock);
 383
 384         have_event = client->packet_head != client->tail;
 385         if (have_event) {
 386                 *event = client->buffer[client->tail++];
 387                 client->tail &= client->bufsize - 1;
 388                 if (client->head == client->tail)
 389                         wake_unlock(&client->wake_lock);
 390         }
 391
 392         spin_unlock_irq(&client->buffer_lock);
 393
 394         return have_event;
 395 }
 396
 397 static ssize_t evdev_read(struct file *file, char __user *buffer,
 398                           size_t count, loff_t *ppos)
 399 {
 400         struct evdev_client *client = file->private_data;
 401         struct evdev *evdev = client->evdev;
 402         struct input_event event;
 403         int retval;
 404
 405         if (count < input_event_size())
 406                 return -EINVAL;
 407
 408         if (!(file->f_flags & O_NONBLOCK)) {
 409                 retval = wait_event_interruptible(evdev->wait,
 410                          client->packet_head != client->tail || !evdev->exist);
 411                 if (retval)
 412                         return retval;
 413         }
 414
 415         if (!evdev->exist)
 416                 return -ENODEV;
 417
 418         while (retval + input_event_size() <= count &&
 419                evdev_fetch_next_event(client, &event)) {
 420
 421                 if (input_event_to_user(buffer + retval, &event))
 422                         return -EFAULT;
 423
 424                 retval += input_event_size();
 425         }
 426
 427         if (retval == 0 && file->f_flags & O_NONBLOCK)
 428                 retval = -EAGAIN;
 429         return retval;
 430 }
 431
 432 /* No kernel lock - fine */
 433 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 434 {
 435         struct evdev_client *client = file->private_data;
 436         struct evdev *evdev = client->evdev;
 437         unsigned int mask;
 438
 439         poll_wait(file, &evdev->wait, wait);
 440
 441         mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
 442         if (client->packet_head != client->tail)
 443                 mask |= POLLIN | POLLRDNORM;
 444
 445         return mask;
 446 }
 447
 448 #ifdef CONFIG_COMPAT
 449
 450 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 451 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 452
 453 #ifdef __BIG_ENDIAN
 454 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 455                         unsigned int maxlen, void __user *p, int compat)
 456 {
 457         int len, i;
 458
 459         if (compat) {
 460                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 461                 if (len > maxlen)
 462                         len = maxlen;
 463
 464                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 465                         if (copy_to_user((compat_long_t __user *) p + i,
 466                                          (compat_long_t *) bits +
 467                                                 i + 1 - ((i % 2) << 1),
 468                                          sizeof(compat_long_t)))
 469                                 return -EFAULT;
 470         } else {
 471                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 472                 if (len > maxlen)
 473                         len = maxlen;
 474
 475                 if (copy_to_user(p, bits, len))
 476                         return -EFAULT;
 477         }
 478
 479         return len;
 480 }
 481 #else
 482 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 483                         unsigned int maxlen, void __user *p, int compat)
 484 {
 485         int len = compat ?
 486                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 487                         BITS_TO_LONGS(maxbit) * sizeof(long);
 488
 489         if (len > maxlen)
 490                 len = maxlen;
 491
 492         return copy_to_user(p, bits, len) ? -EFAULT : len;
 493 }
 494 #endif /* __BIG_ENDIAN */
 495
 496 #else
 497
 498 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 499                         unsigned int maxlen, void __user *p, int compat)
 500 {
 501         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 502
 503         if (len > maxlen)
 504                 len = maxlen;
 505
 506         return copy_to_user(p, bits, len) ? -EFAULT : len;
 507 }
 508
 509 #endif /* CONFIG_COMPAT */
 510
 511 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 512 {
 513         int len;
 514
 515         if (!str)
 516                 return -ENOENT;
 517
 518         len = strlen(str) + 1;
 519         if (len > maxlen)
 520                 len = maxlen;
 521
 522         return copy_to_user(p, str, len) ? -EFAULT : len;
 523 }
 524
 525 #define OLD_KEY_MAX     0x1ff
 526 static int handle_eviocgbit(struct input_dev *dev,
 527                             unsigned int type, unsigned int size,
 528                             void __user *p, int compat_mode)
 529 {
 530         static unsigned long keymax_warn_time;
 531         unsigned long *bits;
 532         int len;
 533
 534         switch (type) {
 535
 536         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 537         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 538         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 539         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 540         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 541         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 542         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 543         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 544         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 545         default: return -EINVAL;
 546         }
 547
 548         /*
 549          * Work around bugs in userspace programs that like to do
 550          * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
 551          * should be in bytes, not in bits.
 552          */
 553         if (type == EV_KEY && size == OLD_KEY_MAX) {
 554                 len = OLD_KEY_MAX;
 555                 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
 556                         pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
 557                                    "limiting output to %zu bytes. See "
 558                                    "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
 559                                    OLD_KEY_MAX,
 560                                    BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
 561         }
 562
 563         return bits_to_user(bits, len, size, p, compat_mode);
 564 }
 565 #undef OLD_KEY_MAX
 566
 567 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
 568 {
 569         struct input_keymap_entry ke = {
 570                 .len    = sizeof(unsigned int),
 571                 .flags  = 0,
 572         };
 573         int __user *ip = (int __user *)p;
 574         int error;
 575
 576         /* legacy case */
 577         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 578                 return -EFAULT;
 579
 580         error = input_get_keycode(dev, &ke);
 581         if (error)
 582                 return error;
 583
 584         if (put_user(ke.keycode, ip + 1))
 585                 return -EFAULT;
 586
 587         return 0;
 588 }
 589
 590 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
 591 {
 592         struct input_keymap_entry ke;
 593         int error;
 594
 595         if (copy_from_user(&ke, p, sizeof(ke)))
 596                 return -EFAULT;
 597
 598         error = input_get_keycode(dev, &ke);
 599         if (error)
 600                 return error;
 601
 602         if (copy_to_user(p, &ke, sizeof(ke)))
 603                 return -EFAULT;
 604
 605         return 0;
 606 }
 607
 608 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
 609 {
 610         struct input_keymap_entry ke = {
 611                 .len    = sizeof(unsigned int),
 612                 .flags  = 0,
 613         };
 614         int __user *ip = (int __user *)p;
 615
 616         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 617                 return -EFAULT;
 618
 619         if (get_user(ke.keycode, ip + 1))
 620                 return -EFAULT;
 621
 622         return input_set_keycode(dev, &ke);
 623 }
 624
 625 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
 626 {
 627         struct input_keymap_entry ke;
 628
 629         if (copy_from_user(&ke, p, sizeof(ke)))
 630                 return -EFAULT;
 631
 632         if (ke.len > sizeof(ke.scancode))
 633                 return -EINVAL;
 634
 635         return input_set_keycode(dev, &ke);
 636 }
 637
 638 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 639                            void __user *p, int compat_mode)
 640 {
 641         struct evdev_client *client = file->private_data;
 642         struct evdev *evdev = client->evdev;
 643         struct input_dev *dev = evdev->handle.dev;
 644         struct input_absinfo abs;
 645         struct ff_effect effect;
 646         int __user *ip = (int __user *)p;
 647         unsigned int i, t, u, v;
 648         unsigned int size;
 649         int error;
 650
 651         /* First we check for fixed-length commands */
 652         switch (cmd) {
 653
 654         case EVIOCGVERSION:
 655                 return put_user(EV_VERSION, ip);
 656
 657         case EVIOCGID:
 658                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 659                         return -EFAULT;
 660                 return 0;
 661
 662         case EVIOCGREP:
 663                 if (!test_bit(EV_REP, dev->evbit))
 664                         return -ENOSYS;
 665                 if (put_user(dev->rep[REP_DELAY], ip))
 666                         return -EFAULT;
 667                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 668                         return -EFAULT;
 669                 return 0;
 670
 671         case EVIOCSREP:
 672                 if (!test_bit(EV_REP, dev->evbit))
 673                         return -ENOSYS;
 674                 if (get_user(u, ip))
 675                         return -EFAULT;
 676                 if (get_user(v, ip + 1))
 677                         return -EFAULT;
 678
 679                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 680                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 681
 682                 return 0;
 683
 684         case EVIOCRMFF:
 685                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 686
 687         case EVIOCGEFFECTS:
 688                 i = test_bit(EV_FF, dev->evbit) ?
 689                                 dev->ff->max_effects : 0;
 690                 if (put_user(i, ip))
 691                         return -EFAULT;
 692                 return 0;
 693
 694         case EVIOCGRAB:
 695                 if (p)
 696                         return evdev_grab(evdev, client);
 697                 else
 698                         return evdev_ungrab(evdev, client);
 699
 700         case EVIOCGKEYCODE:
 701                 return evdev_handle_get_keycode(dev, p);
 702
 703         case EVIOCSKEYCODE:
 704                 return evdev_handle_set_keycode(dev, p);
 705
 706         case EVIOCGKEYCODE_V2:
 707                 return evdev_handle_get_keycode_v2(dev, p);
 708
 709         case EVIOCSKEYCODE_V2:
 710                 return evdev_handle_set_keycode_v2(dev, p);
 711         }
 712
 713         size = _IOC_SIZE(cmd);
 714
 715         /* Now check variable-length commands */
 716 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
 717         switch (EVIOC_MASK_SIZE(cmd)) {
 718
 719         case EVIOCGPROP(0):
 720                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
 721                                     size, p, compat_mode);
 722
 723         case EVIOCGKEY(0):
 724                 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
 725
 726         case EVIOCGLED(0):
 727                 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
 728
 729         case EVIOCGSND(0):
 730                 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
 731
 732         case EVIOCGSW(0):
 733                 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
 734
 735         case EVIOCGNAME(0):
 736                 return str_to_user(dev->name, size, p);
 737
 738         case EVIOCGPHYS(0):
 739                 return str_to_user(dev->phys, size, p);
 740
 741         case EVIOCGUNIQ(0):
 742                 return str_to_user(dev->uniq, size, p);
 743
 744         case EVIOC_MASK_SIZE(EVIOCSFF):
 745                 if (input_ff_effect_from_user(p, size, &effect))
 746                         return -EFAULT;
 747
 748                 error = input_ff_upload(dev, &effect, file);
 749
 750                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 751                         return -EFAULT;
 752
 753                 return error;
 754         }
 755
 756         /* Multi-number variable-length handlers */
 757         if (_IOC_TYPE(cmd) != 'E')
 758                 return -EINVAL;
 759
 760         if (_IOC_DIR(cmd) == _IOC_READ) {
 761
 762                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
 763                         return handle_eviocgbit(dev,
 764                                                 _IOC_NR(cmd) & EV_MAX, size,
 765                                                 p, compat_mode);
 766
 767                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 768
 769                         if (!dev->absinfo)
 770                                 return -EINVAL;
 771
 772                         t = _IOC_NR(cmd) & ABS_MAX;
 773                         abs = dev->absinfo[t];
 774
 775                         if (copy_to_user(p, &abs, min_t(size_t,
 776                                         size, sizeof(struct input_absinfo))))
 777                                 return -EFAULT;
 778
 779                         return 0;
 780                 }
 781         }
 782
 783         if (_IOC_DIR(cmd) == _IOC_WRITE) {
 784
 785                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 786
 787                         if (!dev->absinfo)
 788                                 return -EINVAL;
 789
 790                         t = _IOC_NR(cmd) & ABS_MAX;
 791
 792                         if (copy_from_user(&abs, p, min_t(size_t,
 793                                         size, sizeof(struct input_absinfo))))
 794                                 return -EFAULT;
 795
 796                         if (size < sizeof(struct input_absinfo))
 797                                 abs.resolution = 0;
 798
 799                         /* We can't change number of reserved MT slots */
 800                         if (t == ABS_MT_SLOT)
 801                                 return -EINVAL;
 802
 803                         /*
 804                          * Take event lock to ensure that we are not
 805                          * changing device parameters in the middle
 806                          * of event.
 807                          */
 808                         spin_lock_irq(&dev->event_lock);
 809                         dev->absinfo[t] = abs;
 810                         spin_unlock_irq(&dev->event_lock);
 811
 812                         return 0;
 813                 }
 814         }
 815
 816         return -EINVAL;
 817 }
 818
 819 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 820                                 void __user *p, int compat_mode)
 821 {
 822         struct evdev_client *client = file->private_data;
 823         struct evdev *evdev = client->evdev;
 824         int retval;
 825
 826         retval = mutex_lock_interruptible(&evdev->mutex);
 827         if (retval)
 828                 return retval;
 829
 830         if (!evdev->exist) {
 831                 retval = -ENODEV;
 832                 goto out;
 833         }
 834
 835         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
 836
 837  out:
 838         mutex_unlock(&evdev->mutex);
 839         return retval;
 840 }
 841
 842 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 843 {
 844         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
 845 }
 846
 847 #ifdef CONFIG_COMPAT
 848 static long evdev_ioctl_compat(struct file *file,
 849                                 unsigned int cmd, unsigned long arg)
 850 {
 851         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
 852 }
 853 #endif
 854
 855 static const struct file_operations evdev_fops = {
 856         .owner          = THIS_MODULE,
 857         .read           = evdev_read,
 858         .write          = evdev_write,
 859         .poll           = evdev_poll,
 860         .open           = evdev_open,
 861         .release        = evdev_release,
 862         .unlocked_ioctl = evdev_ioctl,
 863 #ifdef CONFIG_COMPAT
 864         .compat_ioctl   = evdev_ioctl_compat,
 865 #endif
 866         .fasync         = evdev_fasync,
 867         .flush          = evdev_flush,
 868         .llseek         = no_llseek,
 869 };
 870
 871 static int evdev_install_chrdev(struct evdev *evdev)
 872 {
 873         /*
 874          * No need to do any locking here as calls to connect and
 875          * disconnect are serialized by the input core
 876          */
 877         evdev_table[evdev->minor] = evdev;
 878         return 0;
 879 }
 880
 881 static void evdev_remove_chrdev(struct evdev *evdev)
 882 {
 883         /*
 884          * Lock evdev table to prevent race with evdev_open()
 885          */
 886         mutex_lock(&evdev_table_mutex);
 887         evdev_table[evdev->minor] = NULL;
 888         mutex_unlock(&evdev_table_mutex);
 889 }
 890
 891 /*
 892  * Mark device non-existent. This disables writes, ioctls and
 893  * prevents new users from opening the device. Already posted
 894  * blocking reads will stay, however new ones will fail.
 895  */
 896 static void evdev_mark_dead(struct evdev *evdev)
 897 {
 898         mutex_lock(&evdev->mutex);
 899         evdev->exist = false;
 900         mutex_unlock(&evdev->mutex);
 901 }
 902
 903 static void evdev_cleanup(struct evdev *evdev)
 904 {
 905         struct input_handle *handle = &evdev->handle;
 906
 907         evdev_mark_dead(evdev);
 908         evdev_hangup(evdev);
 909         evdev_remove_chrdev(evdev);
 910
 911         /* evdev is marked dead so no one else accesses evdev->open */
 912         if (evdev->open) {
 913                 input_flush_device(handle, NULL);
 914                 input_close_device(handle);
 915         }
 916 }
 917
 918 /*
 919  * Create new evdev device. Note that input core serializes calls
 920  * to connect and disconnect so we don't need to lock evdev_table here.
 921  */
 922 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
 923                          const struct input_device_id *id)
 924 {
 925         struct evdev *evdev;
 926         int minor;
 927         int error;
 928
 929         for (minor = 0; minor < EVDEV_MINORS; minor++)
 930                 if (!evdev_table[minor])
 931                         break;
 932
 933         if (minor == EVDEV_MINORS) {
 934                 pr_err("no more free evdev devices\n");
 935                 return -ENFILE;
 936         }
 937
 938         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
 939         if (!evdev)
 940                 return -ENOMEM;
 941
 942         INIT_LIST_HEAD(&evdev->client_list);
 943         spin_lock_init(&evdev->client_lock);
 944         mutex_init(&evdev->mutex);
 945         init_waitqueue_head(&evdev->wait);
 946
 947         dev_set_name(&evdev->dev, "event%d", minor);
 948         evdev->exist = true;
 949         evdev->minor = minor;
 950
 951         evdev->handle.dev = input_get_device(dev);
 952         evdev->handle.name = dev_name(&evdev->dev);
 953         evdev->handle.handler = handler;
 954         evdev->handle.private = evdev;
 955
 956         evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 957         evdev->dev.class = &input_class;
 958         evdev->dev.parent = &dev->dev;
 959         evdev->dev.release = evdev_free;
 960         device_initialize(&evdev->dev);
 961
 962         error = input_register_handle(&evdev->handle);
 963         if (error)
 964                 goto err_free_evdev;
 965
 966         error = evdev_install_chrdev(evdev);
 967         if (error)
 968                 goto err_unregister_handle;
 969
 970         error = device_add(&evdev->dev);
 971         if (error)
 972                 goto err_cleanup_evdev;
 973
 974         return 0;
 975
 976  err_cleanup_evdev:
 977         evdev_cleanup(evdev);
 978  err_unregister_handle:
 979         input_unregister_handle(&evdev->handle);
 980  err_free_evdev:
 981         put_device(&evdev->dev);
 982         return error;
 983 }
 984
 985 static void evdev_disconnect(struct input_handle *handle)
 986 {
 987         struct evdev *evdev = handle->private;
 988
 989         device_del(&evdev->dev);
 990         evdev_cleanup(evdev);
 991         input_unregister_handle(handle);
 992         put_device(&evdev->dev);
 993 }
 994
 995 static const struct input_device_id evdev_ids[] = {
 996         { .driver_info = 1 },   /* Matches all devices */
 997         { },                    /* Terminating zero entry */
 998 };
 999
1000 MODULE_DEVICE_TABLE(input, evdev_ids);
1001
1002 static struct input_handler evdev_handler = {
1003         .event          = evdev_event,
1004         .connect        = evdev_connect,
1005         .disconnect     = evdev_disconnect,
1006         .fops           = &evdev_fops,
1007         .minor          = EVDEV_MINOR_BASE,
1008         .name           = "evdev",
1009         .id_table       = evdev_ids,
1010 };
1011
1012 static int __init evdev_init(void)
1013 {
1014         return input_register_handler(&evdev_handler);
1015 }
1016
1017 static void __exit evdev_exit(void)
1018 {
1019         input_unregister_handler(&evdev_handler);
1020 }
1021
1022 module_init(evdev_init);
1023 module_exit(evdev_exit);
1024
1025 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1026 MODULE_DESCRIPTION("Input driver event char devices");
1027 MODULE_LICENSE("GPL");