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         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         kfree(evdev);
 128 }
 129
 130 /*
 131  * Grabs an event device (along with underlying input device).
 132  * This function is called with evdev->mutex taken.
 133  */
 134 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 135 {
 136         int error;
 137
 138         if (evdev->grab)
 139                 return -EBUSY;
 140
 141         error = input_grab_device(&evdev->handle);
 142         if (error)
 143                 return error;
 144
 145         rcu_assign_pointer(evdev->grab, client);
 146         synchronize_rcu();
 147
 148         return 0;
 149 }
 150
 151 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 152 {
 153         if (evdev->grab != client)
 154                 return  -EINVAL;
 155
 156         rcu_assign_pointer(evdev->grab, NULL);
 157         synchronize_rcu();
 158         input_release_device(&evdev->handle);
 159
 160         return 0;
 161 }
 162
 163 static void evdev_attach_client(struct evdev *evdev,
 164                                 struct evdev_client *client)
 165 {
 166         spin_lock(&evdev->client_lock);
 167         list_add_tail_rcu(&client->node, &evdev->client_list);
 168         spin_unlock(&evdev->client_lock);
 169         synchronize_rcu();
 170 }
 171
 172 static void evdev_detach_client(struct evdev *evdev,
 173                                 struct evdev_client *client)
 174 {
 175         spin_lock(&evdev->client_lock);
 176         list_del_rcu(&client->node);
 177         spin_unlock(&evdev->client_lock);
 178         synchronize_rcu();
 179 }
 180
 181 static int evdev_open_device(struct evdev *evdev)
 182 {
 183         int retval;
 184
 185         retval = mutex_lock_interruptible(&evdev->mutex);
 186         if (retval)
 187                 return retval;
 188
 189         if (!evdev->exist)
 190                 retval = -ENODEV;
 191         else if (!evdev->open++) {
 192                 retval = input_open_device(&evdev->handle);
 193                 if (retval)
 194                         evdev->open--;
 195         }
 196
 197         mutex_unlock(&evdev->mutex);
 198         return retval;
 199 }
 200
 201 static void evdev_close_device(struct evdev *evdev)
 202 {
 203         mutex_lock(&evdev->mutex);
 204
 205         if (evdev->exist && !--evdev->open)
 206                 input_close_device(&evdev->handle);
 207
 208         mutex_unlock(&evdev->mutex);
 209 }
 210
 211 /*
 212  * Wake up users waiting for IO so they can disconnect from
 213  * dead device.
 214  */
 215 static void evdev_hangup(struct evdev *evdev)
 216 {
 217         struct evdev_client *client;
 218
 219         spin_lock(&evdev->client_lock);
 220         list_for_each_entry(client, &evdev->client_list, node)
 221                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 222         spin_unlock(&evdev->client_lock);
 223
 224         wake_up_interruptible(&evdev->wait);
 225 }
 226
 227 static int evdev_release(struct inode *inode, struct file *file)
 228 {
 229         struct evdev_client *client = file->private_data;
 230         struct evdev *evdev = client->evdev;
 231
 232         mutex_lock(&evdev->mutex);
 233         if (evdev->grab == client)
 234                 evdev_ungrab(evdev, client);
 235         mutex_unlock(&evdev->mutex);
 236
 237         evdev_fasync(-1, file, 0);
 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 #ifdef CONFIG_COMPAT
 294
 295 struct input_event_compat {
 296         struct compat_timeval time;
 297         __u16 type;
 298         __u16 code;
 299         __s32 value;
 300 };
 301
 302 /* Note to the author of this code: did it ever occur to
 303    you why the ifdefs are needed? Think about it again. -AK */
 304 #ifdef CONFIG_X86_64
 305 #  define COMPAT_TEST is_compat_task()
 306 #elif defined(CONFIG_IA64)
 307 #  define COMPAT_TEST IS_IA32_PROCESS(task_pt_regs(current))
 308 #elif defined(CONFIG_S390)
 309 #  define COMPAT_TEST test_thread_flag(TIF_31BIT)
 310 #elif defined(CONFIG_MIPS)
 311 #  define COMPAT_TEST test_thread_flag(TIF_32BIT_ADDR)
 312 #else
 313 #  define COMPAT_TEST test_thread_flag(TIF_32BIT)
 314 #endif
 315
 316 static inline size_t evdev_event_size(void)
 317 {
 318         return COMPAT_TEST ?
 319                 sizeof(struct input_event_compat) : sizeof(struct input_event);
 320 }
 321
 322 static int evdev_event_from_user(const char __user *buffer,
 323                                  struct input_event *event)
 324 {
 325         if (COMPAT_TEST) {
 326                 struct input_event_compat compat_event;
 327
 328                 if (copy_from_user(&compat_event, buffer,
 329                                    sizeof(struct input_event_compat)))
 330                         return -EFAULT;
 331
 332                 event->time.tv_sec = compat_event.time.tv_sec;
 333                 event->time.tv_usec = compat_event.time.tv_usec;
 334                 event->type = compat_event.type;
 335                 event->code = compat_event.code;
 336                 event->value = compat_event.value;
 337
 338         } else {
 339                 if (copy_from_user(event, buffer, sizeof(struct input_event)))
 340                         return -EFAULT;
 341         }
 342
 343         return 0;
 344 }
 345
 346 static int evdev_event_to_user(char __user *buffer,
 347                                 const struct input_event *event)
 348 {
 349         if (COMPAT_TEST) {
 350                 struct input_event_compat compat_event;
 351
 352                 compat_event.time.tv_sec = event->time.tv_sec;
 353                 compat_event.time.tv_usec = event->time.tv_usec;
 354                 compat_event.type = event->type;
 355                 compat_event.code = event->code;
 356                 compat_event.value = event->value;
 357
 358                 if (copy_to_user(buffer, &compat_event,
 359                                  sizeof(struct input_event_compat)))
 360                         return -EFAULT;
 361
 362         } else {
 363                 if (copy_to_user(buffer, event, sizeof(struct input_event)))
 364                         return -EFAULT;
 365         }
 366
 367         return 0;
 368 }
 369
 370 #else
 371
 372 static inline size_t evdev_event_size(void)
 373 {
 374         return sizeof(struct input_event);
 375 }
 376
 377 static int evdev_event_from_user(const char __user *buffer,
 378                                  struct input_event *event)
 379 {
 380         if (copy_from_user(event, buffer, sizeof(struct input_event)))
 381                 return -EFAULT;
 382
 383         return 0;
 384 }
 385
 386 static int evdev_event_to_user(char __user *buffer,
 387                                 const struct input_event *event)
 388 {
 389         if (copy_to_user(buffer, event, sizeof(struct input_event)))
 390                 return -EFAULT;
 391
 392         return 0;
 393 }
 394
 395 #endif /* CONFIG_COMPAT */
 396
 397 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 398                            size_t count, loff_t *ppos)
 399 {
 400         struct evdev_client *client = file->private_data;
 401         struct evdev *evdev = client->evdev;
 402         struct input_event event;
 403         int retval;
 404
 405         retval = mutex_lock_interruptible(&evdev->mutex);
 406         if (retval)
 407                 return retval;
 408
 409         if (!evdev->exist) {
 410                 retval = -ENODEV;
 411                 goto out;
 412         }
 413
 414         while (retval < count) {
 415
 416                 if (evdev_event_from_user(buffer + retval, &event)) {
 417                         retval = -EFAULT;
 418                         goto out;
 419                 }
 420
 421                 input_inject_event(&evdev->handle,
 422                                    event.type, event.code, event.value);
 423                 retval += evdev_event_size();
 424         }
 425
 426  out:
 427         mutex_unlock(&evdev->mutex);
 428         return retval;
 429 }
 430
 431 static int evdev_fetch_next_event(struct evdev_client *client,
 432                                   struct input_event *event)
 433 {
 434         int have_event;
 435
 436         spin_lock_irq(&client->buffer_lock);
 437
 438         have_event = client->head != client->tail;
 439         if (have_event) {
 440                 *event = client->buffer[client->tail++];
 441                 client->tail &= EVDEV_BUFFER_SIZE - 1;
 442         }
 443
 444         spin_unlock_irq(&client->buffer_lock);
 445
 446         return have_event;
 447 }
 448
 449 static ssize_t evdev_read(struct file *file, char __user *buffer,
 450                           size_t count, loff_t *ppos)
 451 {
 452         struct evdev_client *client = file->private_data;
 453         struct evdev *evdev = client->evdev;
 454         struct input_event event;
 455         int retval;
 456
 457         if (count < evdev_event_size())
 458                 return -EINVAL;
 459
 460         if (client->head == client->tail && evdev->exist &&
 461             (file->f_flags & O_NONBLOCK))
 462                 return -EAGAIN;
 463
 464         retval = wait_event_interruptible(evdev->wait,
 465                 client->head != client->tail || !evdev->exist);
 466         if (retval)
 467                 return retval;
 468
 469         if (!evdev->exist)
 470                 return -ENODEV;
 471
 472         while (retval + evdev_event_size() <= count &&
 473                evdev_fetch_next_event(client, &event)) {
 474
 475                 if (evdev_event_to_user(buffer + retval, &event))
 476                         return -EFAULT;
 477
 478                 retval += evdev_event_size();
 479         }
 480
 481         return retval;
 482 }
 483
 484 /* No kernel lock - fine */
 485 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 486 {
 487         struct evdev_client *client = file->private_data;
 488         struct evdev *evdev = client->evdev;
 489
 490         poll_wait(file, &evdev->wait, wait);
 491         return ((client->head == client->tail) ? 0 : (POLLIN | POLLRDNORM)) |
 492                 (evdev->exist ? 0 : (POLLHUP | POLLERR));
 493 }
 494
 495 #ifdef CONFIG_COMPAT
 496
 497 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 498 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 499
 500 #ifdef __BIG_ENDIAN
 501 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 502                         unsigned int maxlen, void __user *p, int compat)
 503 {
 504         int len, i;
 505
 506         if (compat) {
 507                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 508                 if (len > maxlen)
 509                         len = maxlen;
 510
 511                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 512                         if (copy_to_user((compat_long_t __user *) p + i,
 513                                          (compat_long_t *) bits +
 514                                                 i + 1 - ((i % 2) << 1),
 515                                          sizeof(compat_long_t)))
 516                                 return -EFAULT;
 517         } else {
 518                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 519                 if (len > maxlen)
 520                         len = maxlen;
 521
 522                 if (copy_to_user(p, bits, len))
 523                         return -EFAULT;
 524         }
 525
 526         return len;
 527 }
 528 #else
 529 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 530                         unsigned int maxlen, void __user *p, int compat)
 531 {
 532         int len = compat ?
 533                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 534                         BITS_TO_LONGS(maxbit) * sizeof(long);
 535
 536         if (len > maxlen)
 537                 len = maxlen;
 538
 539         return copy_to_user(p, bits, len) ? -EFAULT : len;
 540 }
 541 #endif /* __BIG_ENDIAN */
 542
 543 #else
 544
 545 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 546                         unsigned int maxlen, void __user *p, int compat)
 547 {
 548         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 549
 550         if (len > maxlen)
 551                 len = maxlen;
 552
 553         return copy_to_user(p, bits, len) ? -EFAULT : len;
 554 }
 555
 556 #endif /* CONFIG_COMPAT */
 557
 558 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 559 {
 560         int len;
 561
 562         if (!str)
 563                 return -ENOENT;
 564
 565         len = strlen(str) + 1;
 566         if (len > maxlen)
 567                 len = maxlen;
 568
 569         return copy_to_user(p, str, len) ? -EFAULT : len;
 570 }
 571
 572 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 573                            void __user *p, int compat_mode)
 574 {
 575         struct evdev_client *client = file->private_data;
 576         struct evdev *evdev = client->evdev;
 577         struct input_dev *dev = evdev->handle.dev;
 578         struct input_absinfo abs;
 579         struct ff_effect effect;
 580         int __user *ip = (int __user *)p;
 581         int i, t, u, v;
 582         int error;
 583
 584         switch (cmd) {
 585
 586         case EVIOCGVERSION:
 587                 return put_user(EV_VERSION, ip);
 588
 589         case EVIOCGID:
 590                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 591                         return -EFAULT;
 592                 return 0;
 593
 594         case EVIOCGREP:
 595                 if (!test_bit(EV_REP, dev->evbit))
 596                         return -ENOSYS;
 597                 if (put_user(dev->rep[REP_DELAY], ip))
 598                         return -EFAULT;
 599                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 600                         return -EFAULT;
 601                 return 0;
 602
 603         case EVIOCSREP:
 604                 if (!test_bit(EV_REP, dev->evbit))
 605                         return -ENOSYS;
 606                 if (get_user(u, ip))
 607                         return -EFAULT;
 608                 if (get_user(v, ip + 1))
 609                         return -EFAULT;
 610
 611                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 612                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 613
 614                 return 0;
 615
 616         case EVIOCGKEYCODE:
 617                 if (get_user(t, ip))
 618                         return -EFAULT;
 619
 620                 error = input_get_keycode(dev, t, &v);
 621                 if (error)
 622                         return error;
 623
 624                 if (put_user(v, ip + 1))
 625                         return -EFAULT;
 626
 627                 return 0;
 628
 629         case EVIOCSKEYCODE:
 630                 if (get_user(t, ip) || get_user(v, ip + 1))
 631                         return -EFAULT;
 632
 633                 return input_set_keycode(dev, t, v);
 634
 635         case EVIOCSFF:
 636                 if (copy_from_user(&effect, p, sizeof(effect)))
 637                         return -EFAULT;
 638
 639                 error = input_ff_upload(dev, &effect, file);
 640
 641                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 642                         return -EFAULT;
 643
 644                 return error;
 645
 646         case EVIOCRMFF:
 647                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 648
 649         case EVIOCGEFFECTS:
 650                 i = test_bit(EV_FF, dev->evbit) ?
 651                                 dev->ff->max_effects : 0;
 652                 if (put_user(i, ip))
 653                         return -EFAULT;
 654                 return 0;
 655
 656         case EVIOCGRAB:
 657                 if (p)
 658                         return evdev_grab(evdev, client);
 659                 else
 660                         return evdev_ungrab(evdev, client);
 661
 662         default:
 663
 664                 if (_IOC_TYPE(cmd) != 'E')
 665                         return -EINVAL;
 666
 667                 if (_IOC_DIR(cmd) == _IOC_READ) {
 668
 669                         if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) {
 670
 671                                 unsigned long *bits;
 672                                 int len;
 673
 674                                 switch (_IOC_NR(cmd) & EV_MAX) {
 675
 676                                 case      0: bits = dev->evbit;  len = EV_MAX;  break;
 677                                 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 678                                 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 679                                 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 680                                 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 681                                 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 682                                 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 683                                 case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 684                                 case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 685                                 default: return -EINVAL;
 686                                 }
 687                                 return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
 688                         }
 689
 690                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))
 691                                 return bits_to_user(dev->key, KEY_MAX, _IOC_SIZE(cmd),
 692                                                     p, compat_mode);
 693
 694                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGLED(0)))
 695                                 return bits_to_user(dev->led, LED_MAX, _IOC_SIZE(cmd),
 696                                                     p, compat_mode);
 697
 698                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSND(0)))
 699                                 return bits_to_user(dev->snd, SND_MAX, _IOC_SIZE(cmd),
 700                                                     p, compat_mode);
 701
 702                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSW(0)))
 703                                 return bits_to_user(dev->sw, SW_MAX, _IOC_SIZE(cmd),
 704                                                     p, compat_mode);
 705
 706                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGNAME(0)))
 707                                 return str_to_user(dev->name, _IOC_SIZE(cmd), p);
 708
 709                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGPHYS(0)))
 710                                 return str_to_user(dev->phys, _IOC_SIZE(cmd), p);
 711
 712                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGUNIQ(0)))
 713                                 return str_to_user(dev->uniq, _IOC_SIZE(cmd), p);
 714
 715                         if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 716
 717                                 t = _IOC_NR(cmd) & ABS_MAX;
 718
 719                                 abs.value = dev->abs[t];
 720                                 abs.minimum = dev->absmin[t];
 721                                 abs.maximum = dev->absmax[t];
 722                                 abs.fuzz = dev->absfuzz[t];
 723                                 abs.flat = dev->absflat[t];
 724
 725                                 if (copy_to_user(p, &abs, sizeof(struct input_absinfo)))
 726                                         return -EFAULT;
 727
 728                                 return 0;
 729                         }
 730
 731                 }
 732
 733                 if (_IOC_DIR(cmd) == _IOC_WRITE) {
 734
 735                         if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 736
 737                                 t = _IOC_NR(cmd) & ABS_MAX;
 738
 739                                 if (copy_from_user(&abs, p,
 740                                                 sizeof(struct input_absinfo)))
 741                                         return -EFAULT;
 742
 743                                 /*
 744                                  * Take event lock to ensure that we are not
 745                                  * changing device parameters in the middle
 746                                  * of event.
 747                                  */
 748                                 spin_lock_irq(&dev->event_lock);
 749
 750                                 dev->abs[t] = abs.value;
 751                                 dev->absmin[t] = abs.minimum;
 752                                 dev->absmax[t] = abs.maximum;
 753                                 dev->absfuzz[t] = abs.fuzz;
 754                                 dev->absflat[t] = abs.flat;
 755
 756                                 spin_unlock_irq(&dev->event_lock);
 757
 758                                 return 0;
 759                         }
 760                 }
 761         }
 762         return -EINVAL;
 763 }
 764
 765 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 766                                 void __user *p, int compat_mode)
 767 {
 768         struct evdev_client *client = file->private_data;
 769         struct evdev *evdev = client->evdev;
 770         int retval;
 771
 772         retval = mutex_lock_interruptible(&evdev->mutex);
 773         if (retval)
 774                 return retval;
 775
 776         if (!evdev->exist) {
 777                 retval = -ENODEV;
 778                 goto out;
 779         }
 780
 781         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
 782
 783  out:
 784         mutex_unlock(&evdev->mutex);
 785         return retval;
 786 }
 787
 788 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 789 {
 790         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
 791 }
 792
 793 #ifdef CONFIG_COMPAT
 794 static long evdev_ioctl_compat(struct file *file,
 795                                 unsigned int cmd, unsigned long arg)
 796 {
 797         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
 798 }
 799 #endif
 800
 801 static const struct file_operations evdev_fops = {
 802         .owner          = THIS_MODULE,
 803         .read           = evdev_read,
 804         .write          = evdev_write,
 805         .poll           = evdev_poll,
 806         .open           = evdev_open,
 807         .release        = evdev_release,
 808         .unlocked_ioctl = evdev_ioctl,
 809 #ifdef CONFIG_COMPAT
 810         .compat_ioctl   = evdev_ioctl_compat,
 811 #endif
 812         .fasync         = evdev_fasync,
 813         .flush          = evdev_flush
 814 };
 815
 816 static int evdev_install_chrdev(struct evdev *evdev)
 817 {
 818         /*
 819          * No need to do any locking here as calls to connect and
 820          * disconnect are serialized by the input core
 821          */
 822         evdev_table[evdev->minor] = evdev;
 823         return 0;
 824 }
 825
 826 static void evdev_remove_chrdev(struct evdev *evdev)
 827 {
 828         /*
 829          * Lock evdev table to prevent race with evdev_open()
 830          */
 831         mutex_lock(&evdev_table_mutex);
 832         evdev_table[evdev->minor] = NULL;
 833         mutex_unlock(&evdev_table_mutex);
 834 }
 835
 836 /*
 837  * Mark device non-existent. This disables writes, ioctls and
 838  * prevents new users from opening the device. Already posted
 839  * blocking reads will stay, however new ones will fail.
 840  */
 841 static void evdev_mark_dead(struct evdev *evdev)
 842 {
 843         mutex_lock(&evdev->mutex);
 844         evdev->exist = 0;
 845         mutex_unlock(&evdev->mutex);
 846 }
 847
 848 static void evdev_cleanup(struct evdev *evdev)
 849 {
 850         struct input_handle *handle = &evdev->handle;
 851
 852         evdev_mark_dead(evdev);
 853         evdev_hangup(evdev);
 854         evdev_remove_chrdev(evdev);
 855
 856         /* evdev is marked dead so no one else accesses evdev->open */
 857         if (evdev->open) {
 858                 input_flush_device(handle, NULL);
 859                 input_close_device(handle);
 860         }
 861 }
 862
 863 /*
 864  * Create new evdev device. Note that input core serializes calls
 865  * to connect and disconnect so we don't need to lock evdev_table here.
 866  */
 867 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
 868                          const struct input_device_id *id)
 869 {
 870         struct evdev *evdev;
 871         int minor;
 872         int error;
 873
 874         for (minor = 0; minor < EVDEV_MINORS; minor++)
 875                 if (!evdev_table[minor])
 876                         break;
 877
 878         if (minor == EVDEV_MINORS) {
 879                 printk(KERN_ERR "evdev: no more free evdev devices\n");
 880                 return -ENFILE;
 881         }
 882
 883         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
 884         if (!evdev)
 885                 return -ENOMEM;
 886
 887         INIT_LIST_HEAD(&evdev->client_list);
 888         spin_lock_init(&evdev->client_lock);
 889         mutex_init(&evdev->mutex);
 890         init_waitqueue_head(&evdev->wait);
 891
 892         snprintf(evdev->name, sizeof(evdev->name), "event%d", minor);
 893         evdev->exist = 1;
 894         evdev->minor = minor;
 895
 896         evdev->handle.dev = dev;
 897         evdev->handle.name = evdev->name;
 898         evdev->handle.handler = handler;
 899         evdev->handle.private = evdev;
 900
 901         strlcpy(evdev->dev.bus_id, evdev->name, sizeof(evdev->dev.bus_id));
 902         evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 903         evdev->dev.class = &input_class;
 904         evdev->dev.parent = &dev->dev;
 905         evdev->dev.release = evdev_free;
 906         device_initialize(&evdev->dev);
 907
 908         error = input_register_handle(&evdev->handle);
 909         if (error)
 910                 goto err_free_evdev;
 911
 912         error = evdev_install_chrdev(evdev);
 913         if (error)
 914                 goto err_unregister_handle;
 915
 916         error = device_add(&evdev->dev);
 917         if (error)
 918                 goto err_cleanup_evdev;
 919
 920         return 0;
 921
 922  err_cleanup_evdev:
 923         evdev_cleanup(evdev);
 924  err_unregister_handle:
 925         input_unregister_handle(&evdev->handle);
 926  err_free_evdev:
 927         put_device(&evdev->dev);
 928         return error;
 929 }
 930
 931 static void evdev_disconnect(struct input_handle *handle)
 932 {
 933         struct evdev *evdev = handle->private;
 934
 935         device_del(&evdev->dev);
 936         evdev_cleanup(evdev);
 937         input_unregister_handle(handle);
 938         put_device(&evdev->dev);
 939 }
 940
 941 static const struct input_device_id evdev_ids[] = {
 942         { .driver_info = 1 },   /* Matches all devices */
 943         { },                    /* Terminating zero entry */
 944 };
 945
 946 MODULE_DEVICE_TABLE(input, evdev_ids);
 947
 948 static struct input_handler evdev_handler = {
 949         .event          = evdev_event,
 950         .connect        = evdev_connect,
 951         .disconnect     = evdev_disconnect,
 952         .fops           = &evdev_fops,
 953         .minor          = EVDEV_MINOR_BASE,
 954         .name           = "evdev",
 955         .id_table       = evdev_ids,
 956 };
 957
 958 static int __init evdev_init(void)
 959 {
 960         return input_register_handler(&evdev_handler);
 961 }
 962
 963 static void __exit evdev_exit(void)
 964 {
 965         input_unregister_handler(&evdev_handler);
 966 }
 967
 968 module_init(evdev_init);
 969 module_exit(evdev_exit);
 970
 971 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
 972 MODULE_DESCRIPTION("Input driver event char devices");
 973 MODULE_LICENSE("GPL");