drivers/input/evdev.c

   1 /*
   2  * Event char devices, giving access to raw input device events.
   3  *
   4  * Copyright (c) 1999-2002 Vojtech Pavlik
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  */
  10
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #define EVDEV_MINOR_BASE        64
  14 #define EVDEV_MINORS            32
  15 #define EVDEV_MIN_BUFFER_SIZE   64U
  16 #define EVDEV_BUF_PACKETS       8
  17
  18 #include <linux/poll.h>
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/input.h>
  24 #include <linux/major.h>
  25 #include <linux/device.h>
  26 #include "input-compat.h"
  27
  28 struct evdev {
  29         int open;
  30         int minor;
  31         struct input_handle handle;
  32         wait_queue_head_t wait;
  33         struct evdev_client __rcu *grab;
  34         struct list_head client_list;
  35         spinlock_t client_lock; /* protects client_list */
  36         struct mutex mutex;
  37         struct device dev;
  38         bool exist;
  39 };
  40
  41 struct evdev_client {
  42         unsigned int head;
  43         unsigned int tail;
  44         unsigned int packet_head; /* [future] position of the first element of next packet */
  45         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  46         struct fasync_struct *fasync;
  47         struct evdev *evdev;
  48         struct list_head node;
  49         unsigned int bufsize;
  50         struct input_event buffer[];
  51 };
  52
  53 static struct evdev *evdev_table[EVDEV_MINORS];
  54 static DEFINE_MUTEX(evdev_table_mutex);
  55
  56 static void evdev_pass_event(struct evdev_client *client,
  57                              struct input_event *event)
  58 {
  59         /* Interrupts are disabled, just acquire the lock. */
  60         spin_lock(&client->buffer_lock);
  61
  62         client->buffer[client->head++] = *event;
  63         client->head &= client->bufsize - 1;
  64
  65         if (unlikely(client->head == client->tail)) {
  66                 /*
  67                  * This effectively "drops" all unconsumed events, leaving
  68                  * EV_SYN/SYN_DROPPED plus the newest event in the queue.
  69                  */
  70                 client->tail = (client->head - 2) & (client->bufsize - 1);
  71
  72                 client->buffer[client->tail].time = event->time;
  73                 client->buffer[client->tail].type = EV_SYN;
  74                 client->buffer[client->tail].code = SYN_DROPPED;
  75                 client->buffer[client->tail].value = 0;
  76
  77                 client->packet_head = client->tail;
  78         }
  79
  80         if (event->type == EV_SYN && event->code == SYN_REPORT) {
  81                 client->packet_head = client->head;
  82                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
  83         }
  84
  85         spin_unlock(&client->buffer_lock);
  86 }
  87
  88 /*
  89  * Pass incoming event to all connected clients.
  90  */
  91 static void evdev_event(struct input_handle *handle,
  92                         unsigned int type, unsigned int code, int value)
  93 {
  94         struct evdev *evdev = handle->private;
  95         struct evdev_client *client;
  96         struct input_event event;
  97
  98         do_gettimeofday(&event.time);
  99         event.type = type;
 100         event.code = code;
 101         event.value = value;
 102
 103         rcu_read_lock();
 104
 105         client = rcu_dereference(evdev->grab);
 106         if (client)
 107                 evdev_pass_event(client, &event);
 108         else
 109                 list_for_each_entry_rcu(client, &evdev->client_list, node)
 110                         evdev_pass_event(client, &event);
 111
 112         rcu_read_unlock();
 113
 114         wake_up_interruptible(&evdev->wait);
 115 }
 116
 117 static int evdev_fasync(int fd, struct file *file, int on)
 118 {
 119         struct evdev_client *client = file->private_data;
 120
 121         return fasync_helper(fd, file, on, &client->fasync);
 122 }
 123
 124 static int evdev_flush(struct file *file, fl_owner_t id)
 125 {
 126         struct evdev_client *client = file->private_data;
 127         struct evdev *evdev = client->evdev;
 128         int retval;
 129
 130         retval = mutex_lock_interruptible(&evdev->mutex);
 131         if (retval)
 132                 return retval;
 133
 134         if (!evdev->exist)
 135                 retval = -ENODEV;
 136         else
 137                 retval = input_flush_device(&evdev->handle, file);
 138
 139         mutex_unlock(&evdev->mutex);
 140         return retval;
 141 }
 142
 143 static void evdev_free(struct device *dev)
 144 {
 145         struct evdev *evdev = container_of(dev, struct evdev, dev);
 146
 147         input_put_device(evdev->handle.dev);
 148         kfree(evdev);
 149 }
 150
 151 /*
 152  * Grabs an event device (along with underlying input device).
 153  * This function is called with evdev->mutex taken.
 154  */
 155 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 156 {
 157         int error;
 158
 159         if (evdev->grab)
 160                 return -EBUSY;
 161
 162         error = input_grab_device(&evdev->handle);
 163         if (error)
 164                 return error;
 165
 166         rcu_assign_pointer(evdev->grab, client);
 167         synchronize_rcu();
 168
 169         return 0;
 170 }
 171
 172 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 173 {
 174         if (evdev->grab != client)
 175                 return  -EINVAL;
 176
 177         rcu_assign_pointer(evdev->grab, NULL);
 178         synchronize_rcu();
 179         input_release_device(&evdev->handle);
 180
 181         return 0;
 182 }
 183
 184 static void evdev_attach_client(struct evdev *evdev,
 185                                 struct evdev_client *client)
 186 {
 187         spin_lock(&evdev->client_lock);
 188         list_add_tail_rcu(&client->node, &evdev->client_list);
 189         spin_unlock(&evdev->client_lock);
 190         synchronize_rcu();
 191 }
 192
 193 static void evdev_detach_client(struct evdev *evdev,
 194                                 struct evdev_client *client)
 195 {
 196         spin_lock(&evdev->client_lock);
 197         list_del_rcu(&client->node);
 198         spin_unlock(&evdev->client_lock);
 199         synchronize_rcu();
 200 }
 201
 202 static int evdev_open_device(struct evdev *evdev)
 203 {
 204         int retval;
 205
 206         retval = mutex_lock_interruptible(&evdev->mutex);
 207         if (retval)
 208                 return retval;
 209
 210         if (!evdev->exist)
 211                 retval = -ENODEV;
 212         else if (!evdev->open++) {
 213                 retval = input_open_device(&evdev->handle);
 214                 if (retval)
 215                         evdev->open--;
 216         }
 217
 218         mutex_unlock(&evdev->mutex);
 219         return retval;
 220 }
 221
 222 static void evdev_close_device(struct evdev *evdev)
 223 {
 224         mutex_lock(&evdev->mutex);
 225
 226         if (evdev->exist && !--evdev->open)
 227                 input_close_device(&evdev->handle);
 228
 229         mutex_unlock(&evdev->mutex);
 230 }
 231
 232 /*
 233  * Wake up users waiting for IO so they can disconnect from
 234  * dead device.
 235  */
 236 static void evdev_hangup(struct evdev *evdev)
 237 {
 238         struct evdev_client *client;
 239
 240         spin_lock(&evdev->client_lock);
 241         list_for_each_entry(client, &evdev->client_list, node)
 242                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 243         spin_unlock(&evdev->client_lock);
 244
 245         wake_up_interruptible(&evdev->wait);
 246 }
 247
 248 static int evdev_release(struct inode *inode, struct file *file)
 249 {
 250         struct evdev_client *client = file->private_data;
 251         struct evdev *evdev = client->evdev;
 252
 253         mutex_lock(&evdev->mutex);
 254         if (evdev->grab == client)
 255                 evdev_ungrab(evdev, client);
 256         mutex_unlock(&evdev->mutex);
 257
 258         evdev_detach_client(evdev, client);
 259         kfree(client);
 260
 261         evdev_close_device(evdev);
 262         put_device(&evdev->dev);
 263
 264         return 0;
 265 }
 266
 267 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 268 {
 269         unsigned int n_events =
 270                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 271                     EVDEV_MIN_BUFFER_SIZE);
 272
 273         return roundup_pow_of_two(n_events);
 274 }
 275
 276 static int evdev_open(struct inode *inode, struct file *file)
 277 {
 278         struct evdev *evdev;
 279         struct evdev_client *client;
 280         int i = iminor(inode) - EVDEV_MINOR_BASE;
 281         unsigned int bufsize;
 282         int error;
 283
 284         if (i >= EVDEV_MINORS)
 285                 return -ENODEV;
 286
 287         error = mutex_lock_interruptible(&evdev_table_mutex);
 288         if (error)
 289                 return error;
 290         evdev = evdev_table[i];
 291         if (evdev)
 292                 get_device(&evdev->dev);
 293         mutex_unlock(&evdev_table_mutex);
 294
 295         if (!evdev)
 296                 return -ENODEV;
 297
 298         bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 299
 300         client = kzalloc(sizeof(struct evdev_client) +
 301                                 bufsize * sizeof(struct input_event),
 302                          GFP_KERNEL);
 303         if (!client) {
 304                 error = -ENOMEM;
 305                 goto err_put_evdev;
 306         }
 307
 308         client->bufsize = bufsize;
 309         spin_lock_init(&client->buffer_lock);
 310         client->evdev = evdev;
 311         evdev_attach_client(evdev, client);
 312
 313         error = evdev_open_device(evdev);
 314         if (error)
 315                 goto err_free_client;
 316
 317         file->private_data = client;
 318         nonseekable_open(inode, file);
 319
 320         return 0;
 321
 322  err_free_client:
 323         evdev_detach_client(evdev, client);
 324         kfree(client);
 325  err_put_evdev:
 326         put_device(&evdev->dev);
 327         return error;
 328 }
 329
 330 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 331                            size_t count, loff_t *ppos)
 332 {
 333         struct evdev_client *client = file->private_data;
 334         struct evdev *evdev = client->evdev;
 335         struct input_event event;
 336         int retval;
 337
 338         if (count < input_event_size())
 339                 return -EINVAL;
 340
 341         retval = mutex_lock_interruptible(&evdev->mutex);
 342         if (retval)
 343                 return retval;
 344
 345         if (!evdev->exist) {
 346                 retval = -ENODEV;
 347                 goto out;
 348         }
 349
 350         do {
 351                 if (input_event_from_user(buffer + retval, &event)) {
 352                         retval = -EFAULT;
 353                         goto out;
 354                 }
 355                 retval += input_event_size();
 356
 357                 input_inject_event(&evdev->handle,
 358                                    event.type, event.code, event.value);
 359         } while (retval + input_event_size() <= count);
 360
 361  out:
 362         mutex_unlock(&evdev->mutex);
 363         return retval;
 364 }
 365
 366 static int evdev_fetch_next_event(struct evdev_client *client,
 367                                   struct input_event *event)
 368 {
 369         int have_event;
 370
 371         spin_lock_irq(&client->buffer_lock);
 372
 373         have_event = client->head != client->tail;
 374         if (have_event) {
 375                 *event = client->buffer[client->tail++];
 376                 client->tail &= client->bufsize - 1;
 377         }
 378
 379         spin_unlock_irq(&client->buffer_lock);
 380
 381         return have_event;
 382 }
 383
 384 static ssize_t evdev_read(struct file *file, char __user *buffer,
 385                           size_t count, loff_t *ppos)
 386 {
 387         struct evdev_client *client = file->private_data;
 388         struct evdev *evdev = client->evdev;
 389         struct input_event event;
 390         int retval;
 391
 392         if (count < input_event_size())
 393                 return -EINVAL;
 394
 395         if (client->packet_head == client->tail && evdev->exist &&
 396             (file->f_flags & O_NONBLOCK))
 397                 return -EAGAIN;
 398
 399         retval = wait_event_interruptible(evdev->wait,
 400                 client->packet_head != client->tail || !evdev->exist);
 401         if (retval)
 402                 return retval;
 403
 404         if (!evdev->exist)
 405                 return -ENODEV;
 406
 407         while (retval + input_event_size() <= count &&
 408                evdev_fetch_next_event(client, &event)) {
 409
 410                 if (input_event_to_user(buffer + retval, &event))
 411                         return -EFAULT;
 412
 413                 retval += input_event_size();
 414         }
 415
 416         return retval;
 417 }
 418
 419 /* No kernel lock - fine */
 420 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 421 {
 422         struct evdev_client *client = file->private_data;
 423         struct evdev *evdev = client->evdev;
 424         unsigned int mask;
 425
 426         poll_wait(file, &evdev->wait, wait);
 427
 428         mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
 429         if (client->packet_head != client->tail)
 430                 mask |= POLLIN | POLLRDNORM;
 431
 432         return mask;
 433 }
 434
 435 #ifdef CONFIG_COMPAT
 436
 437 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 438 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 439
 440 #ifdef __BIG_ENDIAN
 441 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 442                         unsigned int maxlen, void __user *p, int compat)
 443 {
 444         int len, i;
 445
 446         if (compat) {
 447                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 448                 if (len > maxlen)
 449                         len = maxlen;
 450
 451                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 452                         if (copy_to_user((compat_long_t __user *) p + i,
 453                                          (compat_long_t *) bits +
 454                                                 i + 1 - ((i % 2) << 1),
 455                                          sizeof(compat_long_t)))
 456                                 return -EFAULT;
 457         } else {
 458                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 459                 if (len > maxlen)
 460                         len = maxlen;
 461
 462                 if (copy_to_user(p, bits, len))
 463                         return -EFAULT;
 464         }
 465
 466         return len;
 467 }
 468 #else
 469 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 470                         unsigned int maxlen, void __user *p, int compat)
 471 {
 472         int len = compat ?
 473                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 474                         BITS_TO_LONGS(maxbit) * sizeof(long);
 475
 476         if (len > maxlen)
 477                 len = maxlen;
 478
 479         return copy_to_user(p, bits, len) ? -EFAULT : len;
 480 }
 481 #endif /* __BIG_ENDIAN */
 482
 483 #else
 484
 485 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 486                         unsigned int maxlen, void __user *p, int compat)
 487 {
 488         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 489
 490         if (len > maxlen)
 491                 len = maxlen;
 492
 493         return copy_to_user(p, bits, len) ? -EFAULT : len;
 494 }
 495
 496 #endif /* CONFIG_COMPAT */
 497
 498 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 499 {
 500         int len;
 501
 502         if (!str)
 503                 return -ENOENT;
 504
 505         len = strlen(str) + 1;
 506         if (len > maxlen)
 507                 len = maxlen;
 508
 509         return copy_to_user(p, str, len) ? -EFAULT : len;
 510 }
 511
 512 #define OLD_KEY_MAX     0x1ff
 513 static int handle_eviocgbit(struct input_dev *dev,
 514                             unsigned int type, unsigned int size,
 515                             void __user *p, int compat_mode)
 516 {
 517         static unsigned long keymax_warn_time;
 518         unsigned long *bits;
 519         int len;
 520
 521         switch (type) {
 522
 523         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 524         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 525         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 526         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 527         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 528         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 529         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 530         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 531         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 532         default: return -EINVAL;
 533         }
 534
 535         /*
 536          * Work around bugs in userspace programs that like to do
 537          * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
 538          * should be in bytes, not in bits.
 539          */
 540         if (type == EV_KEY && size == OLD_KEY_MAX) {
 541                 len = OLD_KEY_MAX;
 542                 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
 543                         pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
 544                                    "limiting output to %zu bytes. See "
 545                                    "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
 546                                    OLD_KEY_MAX,
 547                                    BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
 548         }
 549
 550         return bits_to_user(bits, len, size, p, compat_mode);
 551 }
 552 #undef OLD_KEY_MAX
 553
 554 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
 555 {
 556         struct input_keymap_entry ke = {
 557                 .len    = sizeof(unsigned int),
 558                 .flags  = 0,
 559         };
 560         int __user *ip = (int __user *)p;
 561         int error;
 562
 563         /* legacy case */
 564         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 565                 return -EFAULT;
 566
 567         error = input_get_keycode(dev, &ke);
 568         if (error)
 569                 return error;
 570
 571         if (put_user(ke.keycode, ip + 1))
 572                 return -EFAULT;
 573
 574         return 0;
 575 }
 576
 577 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
 578 {
 579         struct input_keymap_entry ke;
 580         int error;
 581
 582         if (copy_from_user(&ke, p, sizeof(ke)))
 583                 return -EFAULT;
 584
 585         error = input_get_keycode(dev, &ke);
 586         if (error)
 587                 return error;
 588
 589         if (copy_to_user(p, &ke, sizeof(ke)))
 590                 return -EFAULT;
 591
 592         return 0;
 593 }
 594
 595 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
 596 {
 597         struct input_keymap_entry ke = {
 598                 .len    = sizeof(unsigned int),
 599                 .flags  = 0,
 600         };
 601         int __user *ip = (int __user *)p;
 602
 603         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 604                 return -EFAULT;
 605
 606         if (get_user(ke.keycode, ip + 1))
 607                 return -EFAULT;
 608
 609         return input_set_keycode(dev, &ke);
 610 }
 611
 612 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
 613 {
 614         struct input_keymap_entry ke;
 615
 616         if (copy_from_user(&ke, p, sizeof(ke)))
 617                 return -EFAULT;
 618
 619         if (ke.len > sizeof(ke.scancode))
 620                 return -EINVAL;
 621
 622         return input_set_keycode(dev, &ke);
 623 }
 624
 625 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 626                            void __user *p, int compat_mode)
 627 {
 628         struct evdev_client *client = file->private_data;
 629         struct evdev *evdev = client->evdev;
 630         struct input_dev *dev = evdev->handle.dev;
 631         struct input_absinfo abs;
 632         struct ff_effect effect;
 633         int __user *ip = (int __user *)p;
 634         unsigned int i, t, u, v;
 635         unsigned int size;
 636         int error;
 637
 638         /* First we check for fixed-length commands */
 639         switch (cmd) {
 640
 641         case EVIOCGVERSION:
 642                 return put_user(EV_VERSION, ip);
 643
 644         case EVIOCGID:
 645                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 646                         return -EFAULT;
 647                 return 0;
 648
 649         case EVIOCGREP:
 650                 if (!test_bit(EV_REP, dev->evbit))
 651                         return -ENOSYS;
 652                 if (put_user(dev->rep[REP_DELAY], ip))
 653                         return -EFAULT;
 654                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 655                         return -EFAULT;
 656                 return 0;
 657
 658         case EVIOCSREP:
 659                 if (!test_bit(EV_REP, dev->evbit))
 660                         return -ENOSYS;
 661                 if (get_user(u, ip))
 662                         return -EFAULT;
 663                 if (get_user(v, ip + 1))
 664                         return -EFAULT;
 665
 666                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 667                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 668
 669                 return 0;
 670
 671         case EVIOCRMFF:
 672                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 673
 674         case EVIOCGEFFECTS:
 675                 i = test_bit(EV_FF, dev->evbit) ?
 676                                 dev->ff->max_effects : 0;
 677                 if (put_user(i, ip))
 678                         return -EFAULT;
 679                 return 0;
 680
 681         case EVIOCGRAB:
 682                 if (p)
 683                         return evdev_grab(evdev, client);
 684                 else
 685                         return evdev_ungrab(evdev, client);
 686
 687         case EVIOCGKEYCODE:
 688                 return evdev_handle_get_keycode(dev, p);
 689
 690         case EVIOCSKEYCODE:
 691                 return evdev_handle_set_keycode(dev, p);
 692
 693         case EVIOCGKEYCODE_V2:
 694                 return evdev_handle_get_keycode_v2(dev, p);
 695
 696         case EVIOCSKEYCODE_V2:
 697                 return evdev_handle_set_keycode_v2(dev, p);
 698         }
 699
 700         size = _IOC_SIZE(cmd);
 701
 702         /* Now check variable-length commands */
 703 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
 704         switch (EVIOC_MASK_SIZE(cmd)) {
 705
 706         case EVIOCGPROP(0):
 707                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
 708                                     size, p, compat_mode);
 709
 710         case EVIOCGKEY(0):
 711                 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
 712
 713         case EVIOCGLED(0):
 714                 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
 715
 716         case EVIOCGSND(0):
 717                 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
 718
 719         case EVIOCGSW(0):
 720                 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
 721
 722         case EVIOCGNAME(0):
 723                 return str_to_user(dev->name, size, p);
 724
 725         case EVIOCGPHYS(0):
 726                 return str_to_user(dev->phys, size, p);
 727
 728         case EVIOCGUNIQ(0):
 729                 return str_to_user(dev->uniq, size, p);
 730
 731         case EVIOC_MASK_SIZE(EVIOCSFF):
 732                 if (input_ff_effect_from_user(p, size, &effect))
 733                         return -EFAULT;
 734
 735                 error = input_ff_upload(dev, &effect, file);
 736
 737                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 738                         return -EFAULT;
 739
 740                 return error;
 741         }
 742
 743         /* Multi-number variable-length handlers */
 744         if (_IOC_TYPE(cmd) != 'E')
 745                 return -EINVAL;
 746
 747         if (_IOC_DIR(cmd) == _IOC_READ) {
 748
 749                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
 750                         return handle_eviocgbit(dev,
 751                                                 _IOC_NR(cmd) & EV_MAX, size,
 752                                                 p, compat_mode);
 753
 754                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 755
 756                         if (!dev->absinfo)
 757                                 return -EINVAL;
 758
 759                         t = _IOC_NR(cmd) & ABS_MAX;
 760                         abs = dev->absinfo[t];
 761
 762                         if (copy_to_user(p, &abs, min_t(size_t,
 763                                         size, sizeof(struct input_absinfo))))
 764                                 return -EFAULT;
 765
 766                         return 0;
 767                 }
 768         }
 769
 770         if (_IOC_DIR(cmd) == _IOC_WRITE) {
 771
 772                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 773
 774                         if (!dev->absinfo)
 775                                 return -EINVAL;
 776
 777                         t = _IOC_NR(cmd) & ABS_MAX;
 778
 779                         if (copy_from_user(&abs, p, min_t(size_t,
 780                                         size, sizeof(struct input_absinfo))))
 781                                 return -EFAULT;
 782
 783                         if (size < sizeof(struct input_absinfo))
 784                                 abs.resolution = 0;
 785
 786                         /* We can't change number of reserved MT slots */
 787                         if (t == ABS_MT_SLOT)
 788                                 return -EINVAL;
 789
 790                         /*
 791                          * Take event lock to ensure that we are not
 792                          * changing device parameters in the middle
 793                          * of event.
 794                          */
 795                         spin_lock_irq(&dev->event_lock);
 796                         dev->absinfo[t] = abs;
 797                         spin_unlock_irq(&dev->event_lock);
 798
 799                         return 0;
 800                 }
 801         }
 802
 803         return -EINVAL;
 804 }
 805
 806 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 807                                 void __user *p, int compat_mode)
 808 {
 809         struct evdev_client *client = file->private_data;
 810         struct evdev *evdev = client->evdev;
 811         int retval;
 812
 813         retval = mutex_lock_interruptible(&evdev->mutex);
 814         if (retval)
 815                 return retval;
 816
 817         if (!evdev->exist) {
 818                 retval = -ENODEV;
 819                 goto out;
 820         }
 821
 822         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
 823
 824  out:
 825         mutex_unlock(&evdev->mutex);
 826         return retval;
 827 }
 828
 829 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 830 {
 831         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
 832 }
 833
 834 #ifdef CONFIG_COMPAT
 835 static long evdev_ioctl_compat(struct file *file,
 836                                 unsigned int cmd, unsigned long arg)
 837 {
 838         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
 839 }
 840 #endif
 841
 842 static const struct file_operations evdev_fops = {
 843         .owner          = THIS_MODULE,
 844         .read           = evdev_read,
 845         .write          = evdev_write,
 846         .poll           = evdev_poll,
 847         .open           = evdev_open,
 848         .release        = evdev_release,
 849         .unlocked_ioctl = evdev_ioctl,
 850 #ifdef CONFIG_COMPAT
 851         .compat_ioctl   = evdev_ioctl_compat,
 852 #endif
 853         .fasync         = evdev_fasync,
 854         .flush          = evdev_flush,
 855         .llseek         = no_llseek,
 856 };
 857
 858 static int evdev_install_chrdev(struct evdev *evdev)
 859 {
 860         /*
 861          * No need to do any locking here as calls to connect and
 862          * disconnect are serialized by the input core
 863          */
 864         evdev_table[evdev->minor] = evdev;
 865         return 0;
 866 }
 867
 868 static void evdev_remove_chrdev(struct evdev *evdev)
 869 {
 870         /*
 871          * Lock evdev table to prevent race with evdev_open()
 872          */
 873         mutex_lock(&evdev_table_mutex);
 874         evdev_table[evdev->minor] = NULL;
 875         mutex_unlock(&evdev_table_mutex);
 876 }
 877
 878 /*
 879  * Mark device non-existent. This disables writes, ioctls and
 880  * prevents new users from opening the device. Already posted
 881  * blocking reads will stay, however new ones will fail.
 882  */
 883 static void evdev_mark_dead(struct evdev *evdev)
 884 {
 885         mutex_lock(&evdev->mutex);
 886         evdev->exist = false;
 887         mutex_unlock(&evdev->mutex);
 888 }
 889
 890 static void evdev_cleanup(struct evdev *evdev)
 891 {
 892         struct input_handle *handle = &evdev->handle;
 893
 894         evdev_mark_dead(evdev);
 895         evdev_hangup(evdev);
 896         evdev_remove_chrdev(evdev);
 897
 898         /* evdev is marked dead so no one else accesses evdev->open */
 899         if (evdev->open) {
 900                 input_flush_device(handle, NULL);
 901                 input_close_device(handle);
 902         }
 903 }
 904
 905 /*
 906  * Create new evdev device. Note that input core serializes calls
 907  * to connect and disconnect so we don't need to lock evdev_table here.
 908  */
 909 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
 910                          const struct input_device_id *id)
 911 {
 912         struct evdev *evdev;
 913         int minor;
 914         int error;
 915
 916         for (minor = 0; minor < EVDEV_MINORS; minor++)
 917                 if (!evdev_table[minor])
 918                         break;
 919
 920         if (minor == EVDEV_MINORS) {
 921                 pr_err("no more free evdev devices\n");
 922                 return -ENFILE;
 923         }
 924
 925         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
 926         if (!evdev)
 927                 return -ENOMEM;
 928
 929         INIT_LIST_HEAD(&evdev->client_list);
 930         spin_lock_init(&evdev->client_lock);
 931         mutex_init(&evdev->mutex);
 932         init_waitqueue_head(&evdev->wait);
 933
 934         dev_set_name(&evdev->dev, "event%d", minor);
 935         evdev->exist = true;
 936         evdev->minor = minor;
 937
 938         evdev->handle.dev = input_get_device(dev);
 939         evdev->handle.name = dev_name(&evdev->dev);
 940         evdev->handle.handler = handler;
 941         evdev->handle.private = evdev;
 942
 943         evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 944         evdev->dev.class = &input_class;
 945         evdev->dev.parent = &dev->dev;
 946         evdev->dev.release = evdev_free;
 947         device_initialize(&evdev->dev);
 948
 949         error = input_register_handle(&evdev->handle);
 950         if (error)
 951                 goto err_free_evdev;
 952
 953         error = evdev_install_chrdev(evdev);
 954         if (error)
 955                 goto err_unregister_handle;
 956
 957         error = device_add(&evdev->dev);
 958         if (error)
 959                 goto err_cleanup_evdev;
 960
 961         return 0;
 962
 963  err_cleanup_evdev:
 964         evdev_cleanup(evdev);
 965  err_unregister_handle:
 966         input_unregister_handle(&evdev->handle);
 967  err_free_evdev:
 968         put_device(&evdev->dev);
 969         return error;
 970 }
 971
 972 static void evdev_disconnect(struct input_handle *handle)
 973 {
 974         struct evdev *evdev = handle->private;
 975
 976         device_del(&evdev->dev);
 977         evdev_cleanup(evdev);
 978         input_unregister_handle(handle);
 979         put_device(&evdev->dev);
 980 }
 981
 982 static const struct input_device_id evdev_ids[] = {
 983         { .driver_info = 1 },   /* Matches all devices */
 984         { },                    /* Terminating zero entry */
 985 };
 986
 987 MODULE_DEVICE_TABLE(input, evdev_ids);
 988
 989 static struct input_handler evdev_handler = {
 990         .event          = evdev_event,
 991         .connect        = evdev_connect,
 992         .disconnect     = evdev_disconnect,
 993         .fops           = &evdev_fops,
 994         .minor          = EVDEV_MINOR_BASE,
 995         .name           = "evdev",
 996         .id_table       = evdev_ids,
 997 };
 998
 999 static int __init evdev_init(void)
1000 {
1001         return input_register_handler(&evdev_handler);
1002 }
1003
1004 static void __exit evdev_exit(void)
1005 {
1006         input_unregister_handler(&evdev_handler);
1007 }
1008
1009 module_init(evdev_init);
1010 module_exit(evdev_exit);
1011
1012 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1013 MODULE_DESCRIPTION("Input driver event char devices");
1014 MODULE_LICENSE("GPL");