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 <linux/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         int *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         int grab;
  43         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  44         struct fasync_struct *fasync;
  45         struct evdev *evdev;
  46         struct list_head node;
  47 };
  48
  49 static struct evdev *evdev_table[EVDEV_MINORS];
  50 static DEFINE_MUTEX(evdev_table_mutex);
  51
  52 static void evdev_pass_event(struct evdev_client *client,
  53                              struct input_event *event)
  54 {
  55         /*
  56          * Interrupts are disabled, just acquire the lock
  57          */
  58         spin_lock(&client->buffer_lock);
  59         client->buffer[client->head++] = *event;
  60         client->head &= EVDEV_BUFFER_SIZE - 1;
  61         spin_unlock(&client->buffer_lock);
  62
  63         kill_fasync(&client->fasync, SIGIO, POLL_IN);
  64 }
  65
  66 /*
  67  * Pass incoming event to all connected clients.
  68  */
  69 static void evdev_event(struct input_handle *handle,
  70                         unsigned int type, unsigned int code, int value)
  71 {
  72         struct evdev *evdev = handle->private;
  73         struct evdev_client *client;
  74         struct input_event event;
  75
  76         do_gettimeofday(&event.time);
  77         event.type = type;
  78         event.code = code;
  79         event.value = value;
  80
  81         rcu_read_lock();
  82
  83         list_for_each_entry_rcu(client, &evdev->client_list, node)
  84                 evdev_pass_event(client, &event);
  85
  86         rcu_read_unlock();
  87
  88         wake_up_interruptible(&evdev->wait);
  89 }
  90
  91 static int evdev_fasync(int fd, struct file *file, int on)
  92 {
  93         struct evdev_client *client = file->private_data;
  94         int retval;
  95
  96         retval = fasync_helper(fd, file, on, &client->fasync);
  97
  98         return retval < 0 ? retval : 0;
  99 }
 100
 101 static int evdev_flush(struct file *file, fl_owner_t id)
 102 {
 103         struct evdev_client *client = file->private_data;
 104         struct evdev *evdev = client->evdev;
 105         int retval;
 106
 107         retval = mutex_lock_interruptible(&evdev->mutex);
 108         if (retval)
 109                 return retval;
 110
 111         if (!evdev->exist)
 112                 retval = -ENODEV;
 113         else
 114                 retval = input_flush_device(&evdev->handle, file);
 115
 116         mutex_unlock(&evdev->mutex);
 117         return retval;
 118 }
 119
 120 static void evdev_free(struct device *dev)
 121 {
 122         struct evdev *evdev = container_of(dev, struct evdev, dev);
 123
 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 (client->grab)
 136                 return -EBUSY;
 137
 138         if (!evdev->grab++) {
 139             error = input_grab_device(&evdev->handle);
 140             if (error)
 141                     return error;
 142         }
 143         client->grab = 1;
 144         synchronize_rcu();
 145
 146         return 0;
 147 }
 148
 149 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 150 {
 151         if (!client->grab)
 152                 return  -EINVAL;
 153
 154         if (!--evdev->grab && evdev->exist)
 155                 input_release_device(&evdev->handle);
 156         client->grab = 0;
 157
 158         return 0;
 159 }
 160
 161 static void evdev_attach_client(struct evdev *evdev,
 162                                 struct evdev_client *client)
 163 {
 164         spin_lock(&evdev->client_lock);
 165         list_add_tail_rcu(&client->node, &evdev->client_list);
 166         spin_unlock(&evdev->client_lock);
 167         synchronize_rcu();
 168 }
 169
 170 static void evdev_detach_client(struct evdev *evdev,
 171                                 struct evdev_client *client)
 172 {
 173         spin_lock(&evdev->client_lock);
 174         list_del_rcu(&client->node);
 175         spin_unlock(&evdev->client_lock);
 176         synchronize_rcu();
 177 }
 178
 179 static int evdev_open_device(struct evdev *evdev)
 180 {
 181         int retval;
 182
 183         retval = mutex_lock_interruptible(&evdev->mutex);
 184         if (retval)
 185                 return retval;
 186
 187         if (!evdev->exist)
 188                 retval = -ENODEV;
 189         else if (!evdev->open++) {
 190                 retval = input_open_device(&evdev->handle);
 191                 if (retval)
 192                         evdev->open--;
 193         }
 194
 195         mutex_unlock(&evdev->mutex);
 196         return retval;
 197 }
 198
 199 static void evdev_close_device(struct evdev *evdev)
 200 {
 201         mutex_lock(&evdev->mutex);
 202
 203         if (evdev->exist && !--evdev->open)
 204                 input_close_device(&evdev->handle);
 205
 206         mutex_unlock(&evdev->mutex);
 207 }
 208
 209 /*
 210  * Wake up users waiting for IO so they can disconnect from
 211  * dead device.
 212  */
 213 static void evdev_hangup(struct evdev *evdev)
 214 {
 215         struct evdev_client *client;
 216
 217         spin_lock(&evdev->client_lock);
 218         list_for_each_entry(client, &evdev->client_list, node)
 219                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 220         spin_unlock(&evdev->client_lock);
 221
 222         wake_up_interruptible(&evdev->wait);
 223 }
 224
 225 static int evdev_release(struct inode *inode, struct file *file)
 226 {
 227         struct evdev_client *client = file->private_data;
 228         struct evdev *evdev = client->evdev;
 229
 230         mutex_lock(&evdev->mutex);
 231         if (client->grab)
 232                 evdev_ungrab(evdev, client);
 233         mutex_unlock(&evdev->mutex);
 234
 235         evdev_fasync(-1, file, 0);
 236         evdev_detach_client(evdev, client);
 237         kfree(client);
 238
 239         evdev_close_device(evdev);
 240         put_device(&evdev->dev);
 241
 242         return 0;
 243 }
 244
 245 static int evdev_open(struct inode *inode, struct file *file)
 246 {
 247         struct evdev *evdev;
 248         struct evdev_client *client;
 249         int i = iminor(inode) - EVDEV_MINOR_BASE;
 250         int error;
 251
 252         if (i >= EVDEV_MINORS)
 253                 return -ENODEV;
 254
 255         error = mutex_lock_interruptible(&evdev_table_mutex);
 256         if (error)
 257                 return error;
 258         evdev = evdev_table[i];
 259         if (evdev)
 260                 get_device(&evdev->dev);
 261         mutex_unlock(&evdev_table_mutex);
 262
 263         if (!evdev)
 264                 return -ENODEV;
 265
 266         client = kzalloc(sizeof(struct evdev_client), GFP_KERNEL);
 267         if (!client) {
 268                 error = -ENOMEM;
 269                 goto err_put_evdev;
 270         }
 271
 272         spin_lock_init(&client->buffer_lock);
 273         client->evdev = evdev;
 274         evdev_attach_client(evdev, client);
 275
 276         error = evdev_open_device(evdev);
 277         if (error)
 278                 goto err_free_client;
 279
 280         file->private_data = client;
 281         return 0;
 282
 283  err_free_client:
 284         evdev_detach_client(evdev, client);
 285         kfree(client);
 286  err_put_evdev:
 287         put_device(&evdev->dev);
 288         return error;
 289 }
 290
 291 #ifdef CONFIG_COMPAT
 292
 293 struct input_event_compat {
 294         struct compat_timeval time;
 295         __u16 type;
 296         __u16 code;
 297         __s32 value;
 298 };
 299
 300 /* Note to the author of this code: did it ever occur to
 301    you why the ifdefs are needed? Think about it again. -AK */
 302 #ifdef CONFIG_X86_64
 303 #  define COMPAT_TEST is_compat_task()
 304 #elif defined(CONFIG_IA64)
 305 #  define COMPAT_TEST IS_IA32_PROCESS(task_pt_regs(current))
 306 #elif defined(CONFIG_S390)
 307 #  define COMPAT_TEST test_thread_flag(TIF_31BIT)
 308 #elif defined(CONFIG_MIPS)
 309 #  define COMPAT_TEST test_thread_flag(TIF_32BIT_ADDR)
 310 #else
 311 #  define COMPAT_TEST test_thread_flag(TIF_32BIT)
 312 #endif
 313
 314 static inline size_t evdev_event_size(void)
 315 {
 316         return COMPAT_TEST ?
 317                 sizeof(struct input_event_compat) : sizeof(struct input_event);
 318 }
 319
 320 static int evdev_event_from_user(const char __user *buffer,
 321                                  struct input_event *event)
 322 {
 323         if (COMPAT_TEST) {
 324                 struct input_event_compat compat_event;
 325
 326                 if (copy_from_user(&compat_event, buffer,
 327                                    sizeof(struct input_event_compat)))
 328                         return -EFAULT;
 329
 330                 event->time.tv_sec = compat_event.time.tv_sec;
 331                 event->time.tv_usec = compat_event.time.tv_usec;
 332                 event->type = compat_event.type;
 333                 event->code = compat_event.code;
 334                 event->value = compat_event.value;
 335
 336         } else {
 337                 if (copy_from_user(event, buffer, sizeof(struct input_event)))
 338                         return -EFAULT;
 339         }
 340
 341         return 0;
 342 }
 343
 344 static int evdev_event_to_user(char __user *buffer,
 345                                 const struct input_event *event)
 346 {
 347         if (COMPAT_TEST) {
 348                 struct input_event_compat compat_event;
 349
 350                 compat_event.time.tv_sec = event->time.tv_sec;
 351                 compat_event.time.tv_usec = event->time.tv_usec;
 352                 compat_event.type = event->type;
 353                 compat_event.code = event->code;
 354                 compat_event.value = event->value;
 355
 356                 if (copy_to_user(buffer, &compat_event,
 357                                  sizeof(struct input_event_compat)))
 358                         return -EFAULT;
 359
 360         } else {
 361                 if (copy_to_user(buffer, event, sizeof(struct input_event)))
 362                         return -EFAULT;
 363         }
 364
 365         return 0;
 366 }
 367
 368 #else
 369
 370 static inline size_t evdev_event_size(void)
 371 {
 372         return sizeof(struct input_event);
 373 }
 374
 375 static int evdev_event_from_user(const char __user *buffer,
 376                                  struct input_event *event)
 377 {
 378         if (copy_from_user(event, buffer, sizeof(struct input_event)))
 379                 return -EFAULT;
 380
 381         return 0;
 382 }
 383
 384 static int evdev_event_to_user(char __user *buffer,
 385                                 const struct input_event *event)
 386 {
 387         if (copy_to_user(buffer, event, sizeof(struct input_event)))
 388                 return -EFAULT;
 389
 390         return 0;
 391 }
 392
 393 #endif /* CONFIG_COMPAT */
 394
 395 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 396                            size_t count, loff_t *ppos)
 397 {
 398         struct evdev_client *client = file->private_data;
 399         struct evdev *evdev = client->evdev;
 400         struct input_event event;
 401         int retval;
 402
 403         retval = mutex_lock_interruptible(&evdev->mutex);
 404         if (retval)
 405                 return retval;
 406
 407         if (!evdev->exist) {
 408                 retval = -ENODEV;
 409                 goto out;
 410         }
 411
 412         while (retval < count) {
 413
 414                 if (evdev_event_from_user(buffer + retval, &event)) {
 415                         retval = -EFAULT;
 416                         goto out;
 417                 }
 418
 419                 input_inject_event(&evdev->handle,
 420                                    event.type, event.code, event.value);
 421                 retval += evdev_event_size();
 422         }
 423
 424  out:
 425         mutex_unlock(&evdev->mutex);
 426         return retval;
 427 }
 428
 429 static int evdev_fetch_next_event(struct evdev_client *client,
 430                                   struct input_event *event)
 431 {
 432         int have_event;
 433
 434         spin_lock_irq(&client->buffer_lock);
 435
 436         have_event = client->head != client->tail;
 437         if (have_event) {
 438                 *event = client->buffer[client->tail++];
 439                 client->tail &= EVDEV_BUFFER_SIZE - 1;
 440         }
 441
 442         spin_unlock_irq(&client->buffer_lock);
 443
 444         return have_event;
 445 }
 446
 447 static ssize_t evdev_read(struct file *file, char __user *buffer,
 448                           size_t count, loff_t *ppos)
 449 {
 450         struct evdev_client *client = file->private_data;
 451         struct evdev *evdev = client->evdev;
 452         struct input_event event;
 453         int retval;
 454
 455         if (count < evdev_event_size())
 456                 return -EINVAL;
 457
 458         if (client->head == client->tail && evdev->exist &&
 459             (file->f_flags & O_NONBLOCK))
 460                 return -EAGAIN;
 461
 462         retval = wait_event_interruptible(evdev->wait,
 463                 client->head != client->tail || !evdev->exist);
 464         if (retval)
 465                 return retval;
 466
 467         if (!evdev->exist)
 468                 return -ENODEV;
 469
 470         while (retval + evdev_event_size() <= count &&
 471                evdev_fetch_next_event(client, &event)) {
 472
 473                 if (evdev_event_to_user(buffer + retval, &event))
 474                         return -EFAULT;
 475
 476                 retval += evdev_event_size();
 477         }
 478
 479         return retval;
 480 }
 481
 482 /* No kernel lock - fine */
 483 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 484 {
 485         struct evdev_client *client = file->private_data;
 486         struct evdev *evdev = client->evdev;
 487
 488         poll_wait(file, &evdev->wait, wait);
 489         return ((client->head == client->tail) ? 0 : (POLLIN | POLLRDNORM)) |
 490                 (evdev->exist ? 0 : (POLLHUP | POLLERR));
 491 }
 492
 493 #ifdef CONFIG_COMPAT
 494
 495 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 496 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 497
 498 #ifdef __BIG_ENDIAN
 499 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 500                         unsigned int maxlen, void __user *p, int compat)
 501 {
 502         int len, i;
 503
 504         if (compat) {
 505                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 506                 if (len > maxlen)
 507                         len = maxlen;
 508
 509                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 510                         if (copy_to_user((compat_long_t __user *) p + i,
 511                                          (compat_long_t *) bits +
 512                                                 i + 1 - ((i % 2) << 1),
 513                                          sizeof(compat_long_t)))
 514                                 return -EFAULT;
 515         } else {
 516                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 517                 if (len > maxlen)
 518                         len = maxlen;
 519
 520                 if (copy_to_user(p, bits, len))
 521                         return -EFAULT;
 522         }
 523
 524         return len;
 525 }
 526 #else
 527 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 528                         unsigned int maxlen, void __user *p, int compat)
 529 {
 530         int len = compat ?
 531                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 532                         BITS_TO_LONGS(maxbit) * sizeof(long);
 533
 534         if (len > maxlen)
 535                 len = maxlen;
 536
 537         return copy_to_user(p, bits, len) ? -EFAULT : len;
 538 }
 539 #endif /* __BIG_ENDIAN */
 540
 541 #else
 542
 543 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 544                         unsigned int maxlen, void __user *p, int compat)
 545 {
 546         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 547
 548         if (len > maxlen)
 549                 len = maxlen;
 550
 551         return copy_to_user(p, bits, len) ? -EFAULT : len;
 552 }
 553
 554 #endif /* CONFIG_COMPAT */
 555
 556 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 557 {
 558         int len;
 559
 560         if (!str)
 561                 return -ENOENT;
 562
 563         len = strlen(str) + 1;
 564         if (len > maxlen)
 565                 len = maxlen;
 566
 567         return copy_to_user(p, str, len) ? -EFAULT : len;
 568 }
 569
 570 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 571                            void __user *p, int compat_mode)
 572 {
 573         struct evdev_client *client = file->private_data;
 574         struct evdev *evdev = client->evdev;
 575         struct input_dev *dev = evdev->handle.dev;
 576         struct input_absinfo abs;
 577         struct ff_effect effect;
 578         int __user *ip = (int __user *)p;
 579         int i, t, u, v;
 580         int error;
 581
 582         switch (cmd) {
 583
 584         case EVIOCGVERSION:
 585                 return put_user(EV_VERSION, ip);
 586
 587         case EVIOCGID:
 588                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 589                         return -EFAULT;
 590                 return 0;
 591
 592         case EVIOCGREP:
 593                 if (!test_bit(EV_REP, dev->evbit))
 594                         return -ENOSYS;
 595                 if (put_user(dev->rep[REP_DELAY], ip))
 596                         return -EFAULT;
 597                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 598                         return -EFAULT;
 599                 return 0;
 600
 601         case EVIOCSREP:
 602                 if (!test_bit(EV_REP, dev->evbit))
 603                         return -ENOSYS;
 604                 if (get_user(u, ip))
 605                         return -EFAULT;
 606                 if (get_user(v, ip + 1))
 607                         return -EFAULT;
 608
 609                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 610                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 611
 612                 return 0;
 613
 614         case EVIOCGKEYCODE:
 615                 if (get_user(t, ip))
 616                         return -EFAULT;
 617
 618                 error = dev->getkeycode(dev, t, &v);
 619                 if (error)
 620                         return error;
 621
 622                 if (put_user(v, ip + 1))
 623                         return -EFAULT;
 624
 625                 return 0;
 626
 627         case EVIOCSKEYCODE:
 628                 if (get_user(t, ip) || get_user(v, ip + 1))
 629                         return -EFAULT;
 630
 631                 return dev->setkeycode(dev, t, v);
 632
 633         case EVIOCSFF:
 634                 if (copy_from_user(&effect, p, sizeof(effect)))
 635                         return -EFAULT;
 636
 637                 error = input_ff_upload(dev, &effect, file);
 638
 639                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 640                         return -EFAULT;
 641
 642                 return error;
 643
 644         case EVIOCRMFF:
 645                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 646
 647         case EVIOCGEFFECTS:
 648                 i = test_bit(EV_FF, dev->evbit) ?
 649                                 dev->ff->max_effects : 0;
 650                 if (put_user(i, ip))
 651                         return -EFAULT;
 652                 return 0;
 653
 654         case EVIOCGRAB:
 655                 if (p)
 656                         return evdev_grab(evdev, client);
 657                 else
 658                         return evdev_ungrab(evdev, client);
 659
 660         default:
 661
 662                 if (_IOC_TYPE(cmd) != 'E')
 663                         return -EINVAL;
 664
 665                 if (_IOC_DIR(cmd) == _IOC_READ) {
 666
 667                         if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) {
 668
 669                                 unsigned long *bits;
 670                                 int len;
 671
 672                                 switch (_IOC_NR(cmd) & EV_MAX) {
 673
 674                                 case      0: bits = dev->evbit;  len = EV_MAX;  break;
 675                                 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 676                                 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 677                                 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 678                                 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 679                                 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 680                                 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 681                                 case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 682                                 case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 683                                 default: return -EINVAL;
 684                         }
 685                                 return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
 686                         }
 687
 688                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))
 689                                 return bits_to_user(dev->key, KEY_MAX, _IOC_SIZE(cmd),
 690                                                     p, compat_mode);
 691
 692                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGLED(0)))
 693                                 return bits_to_user(dev->led, LED_MAX, _IOC_SIZE(cmd),
 694                                                     p, compat_mode);
 695
 696                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSND(0)))
 697                                 return bits_to_user(dev->snd, SND_MAX, _IOC_SIZE(cmd),
 698                                                     p, compat_mode);
 699
 700                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSW(0)))
 701                                 return bits_to_user(dev->sw, SW_MAX, _IOC_SIZE(cmd),
 702                                                     p, compat_mode);
 703
 704                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGNAME(0)))
 705                                 return str_to_user(dev->name, _IOC_SIZE(cmd), p);
 706
 707                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGPHYS(0)))
 708                                 return str_to_user(dev->phys, _IOC_SIZE(cmd), p);
 709
 710                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGUNIQ(0)))
 711                                 return str_to_user(dev->uniq, _IOC_SIZE(cmd), p);
 712
 713                         if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 714
 715                                 t = _IOC_NR(cmd) & ABS_MAX;
 716
 717                                 abs.value = dev->abs[t];
 718                                 abs.minimum = dev->absmin[t];
 719                                 abs.maximum = dev->absmax[t];
 720                                 abs.fuzz = dev->absfuzz[t];
 721                                 abs.flat = dev->absflat[t];
 722
 723                                 if (copy_to_user(p, &abs, sizeof(struct input_absinfo)))
 724                                         return -EFAULT;
 725
 726                                 return 0;
 727                         }
 728
 729                 }
 730
 731                 if (_IOC_DIR(cmd) == _IOC_WRITE) {
 732
 733                         if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 734
 735                                 t = _IOC_NR(cmd) & ABS_MAX;
 736
 737                                 if (copy_from_user(&abs, p,
 738                                                 sizeof(struct input_absinfo)))
 739                                         return -EFAULT;
 740
 741                                 /*
 742                                  * Take event lock to ensure that we are not
 743                                  * changing device parameters in the middle
 744                                  * of event.
 745                                  */
 746                                 spin_lock_irq(&dev->event_lock);
 747
 748                                 dev->abs[t] = abs.value;
 749                                 dev->absmin[t] = abs.minimum;
 750                                 dev->absmax[t] = abs.maximum;
 751                                 dev->absfuzz[t] = abs.fuzz;
 752                                 dev->absflat[t] = abs.flat;
 753
 754                                 spin_unlock_irq(&dev->event_lock);
 755
 756                                 return 0;
 757                         }
 758                 }
 759         }
 760         return -EINVAL;
 761 }
 762
 763 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 764                                 void __user *p, int compat_mode)
 765 {
 766         struct evdev_client *client = file->private_data;
 767         struct evdev *evdev = client->evdev;
 768         int retval;
 769
 770         retval = mutex_lock_interruptible(&evdev->mutex);
 771         if (retval)
 772                 return retval;
 773
 774         if (!evdev->exist) {
 775                 retval = -ENODEV;
 776                 goto out;
 777         }
 778
 779         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
 780
 781  out:
 782         mutex_unlock(&evdev->mutex);
 783         return retval;
 784 }
 785
 786 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 787 {
 788         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
 789 }
 790
 791 #ifdef CONFIG_COMPAT
 792 static long evdev_ioctl_compat(struct file *file,
 793                                 unsigned int cmd, unsigned long arg)
 794 {
 795         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
 796 }
 797 #endif
 798
 799 static const struct file_operations evdev_fops = {
 800         .owner          = THIS_MODULE,
 801         .read           = evdev_read,
 802         .write          = evdev_write,
 803         .poll           = evdev_poll,
 804         .open           = evdev_open,
 805         .release        = evdev_release,
 806         .unlocked_ioctl = evdev_ioctl,
 807 #ifdef CONFIG_COMPAT
 808         .compat_ioctl   = evdev_ioctl_compat,
 809 #endif
 810         .fasync         = evdev_fasync,
 811         .flush          = evdev_flush
 812 };
 813
 814 static int evdev_install_chrdev(struct evdev *evdev)
 815 {
 816         /*
 817          * No need to do any locking here as calls to connect and
 818          * disconnect are serialized by the input core
 819          */
 820         evdev_table[evdev->minor] = evdev;
 821         return 0;
 822 }
 823
 824 static void evdev_remove_chrdev(struct evdev *evdev)
 825 {
 826         /*
 827          * Lock evdev table to prevent race with evdev_open()
 828          */
 829         mutex_lock(&evdev_table_mutex);
 830         evdev_table[evdev->minor] = NULL;
 831         mutex_unlock(&evdev_table_mutex);
 832 }
 833
 834 /*
 835  * Mark device non-existent. This disables writes, ioctls and
 836  * prevents new users from opening the device. Already posted
 837  * blocking reads will stay, however new ones will fail.
 838  */
 839 static void evdev_mark_dead(struct evdev *evdev)
 840 {
 841         mutex_lock(&evdev->mutex);
 842         evdev->exist = 0;
 843         mutex_unlock(&evdev->mutex);
 844 }
 845
 846 static void evdev_cleanup(struct evdev *evdev)
 847 {
 848         struct input_handle *handle = &evdev->handle;
 849
 850         evdev_mark_dead(evdev);
 851         evdev_hangup(evdev);
 852         evdev_remove_chrdev(evdev);
 853
 854         /* evdev is marked dead so no one else accesses evdev->open */
 855         if (evdev->open) {
 856                 input_flush_device(handle, NULL);
 857                 input_close_device(handle);
 858         }
 859 }
 860
 861 /*
 862  * Create new evdev device. Note that input core serializes calls
 863  * to connect and disconnect so we don't need to lock evdev_table here.
 864  */
 865 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
 866                          const struct input_device_id *id)
 867 {
 868         struct evdev *evdev;
 869         int minor;
 870         int error;
 871
 872         for (minor = 0; minor < EVDEV_MINORS; minor++)
 873                 if (!evdev_table[minor])
 874                         break;
 875
 876         if (minor == EVDEV_MINORS) {
 877                 printk(KERN_ERR "evdev: no more free evdev devices\n");
 878                 return -ENFILE;
 879         }
 880
 881         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
 882         if (!evdev)
 883                 return -ENOMEM;
 884
 885         INIT_LIST_HEAD(&evdev->client_list);
 886         spin_lock_init(&evdev->client_lock);
 887         mutex_init(&evdev->mutex);
 888         init_waitqueue_head(&evdev->wait);
 889
 890         snprintf(evdev->name, sizeof(evdev->name), "event%d", minor);
 891         evdev->exist = 1;
 892         evdev->minor = minor;
 893
 894         evdev->handle.dev = dev;
 895         evdev->handle.name = evdev->name;
 896         evdev->handle.handler = handler;
 897         evdev->handle.private = evdev;
 898
 899         strlcpy(evdev->dev.bus_id, evdev->name, sizeof(evdev->dev.bus_id));
 900         evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 901         evdev->dev.class = &input_class;
 902         evdev->dev.parent = &dev->dev;
 903         evdev->dev.release = evdev_free;
 904         device_initialize(&evdev->dev);
 905
 906         error = input_register_handle(&evdev->handle);
 907         if (error)
 908                 goto err_free_evdev;
 909
 910         error = evdev_install_chrdev(evdev);
 911         if (error)
 912                 goto err_unregister_handle;
 913
 914         error = device_add(&evdev->dev);
 915         if (error)
 916                 goto err_cleanup_evdev;
 917
 918         return 0;
 919
 920  err_cleanup_evdev:
 921         evdev_cleanup(evdev);
 922  err_unregister_handle:
 923         input_unregister_handle(&evdev->handle);
 924  err_free_evdev:
 925         put_device(&evdev->dev);
 926         return error;
 927 }
 928
 929 static void evdev_disconnect(struct input_handle *handle)
 930 {
 931         struct evdev *evdev = handle->private;
 932
 933         device_del(&evdev->dev);
 934         evdev_cleanup(evdev);
 935         input_unregister_handle(handle);
 936         put_device(&evdev->dev);
 937 }
 938
 939 static const struct input_device_id evdev_ids[] = {
 940         { .driver_info = 1 },   /* Matches all devices */
 941         { },                    /* Terminating zero entry */
 942 };
 943
 944 MODULE_DEVICE_TABLE(input, evdev_ids);
 945
 946 static struct input_handler evdev_handler = {
 947         .event          = evdev_event,
 948         .connect        = evdev_connect,
 949         .disconnect     = evdev_disconnect,
 950         .fops           = &evdev_fops,
 951         .minor          = EVDEV_MINOR_BASE,
 952         .name           = "evdev",
 953         .id_table       = evdev_ids,
 954 };
 955
 956 static int __init evdev_init(void)
 957 {
 958         return input_register_handler(&evdev_handler);
 959 }
 960
 961 static void __exit evdev_exit(void)
 962 {
 963         input_unregister_handler(&evdev_handler);
 964 }
 965
 966 module_init(evdev_init);
 967 module_exit(evdev_exit);
 968
 969 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
 970 MODULE_DESCRIPTION("Input driver event char devices");
 971 MODULE_LICENSE("GPL");