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