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