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