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