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