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