drivers/input/evdev.c

   1 /*
   2  * Event char devices, giving access to raw input device events.
   3  *
   4  * Copyright (c) 1999-2002 Vojtech Pavlik
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  */
  10
  11 #define EVDEV_MINOR_BASE        64
  12 #define EVDEV_MINORS            32
  13 #define EVDEV_MIN_BUFFER_SIZE   64U
  14 #define EVDEV_BUF_PACKETS       8
  15
  16 #include <linux/poll.h>
  17 #include <linux/sched.h>
  18 #include <linux/slab.h>
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <linux/input.h>
  22 #include <linux/major.h>
  23 #include <linux/device.h>
  24 #include "input-compat.h"
  25
  26 struct evdev {
  27         int exist;
  28         int open;
  29         int minor;
  30         struct input_handle handle;
  31         wait_queue_head_t wait;
  32         struct evdev_client *grab;
  33         struct list_head client_list;
  34         spinlock_t client_lock; /* protects client_list */
  35         struct mutex mutex;
  36         struct device dev;
  37 };
  38
  39 struct evdev_client {
  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         int bufsize;
  47         struct input_event buffer[];
  48 };
  49
  50 static struct evdev *evdev_table[EVDEV_MINORS];
  51 static DEFINE_MUTEX(evdev_table_mutex);
  52
  53 static void evdev_pass_event(struct evdev_client *client,
  54                              struct input_event *event)
  55 {
  56         /*
  57          * Interrupts are disabled, just acquire the lock
  58          */
  59         spin_lock(&client->buffer_lock);
  60         client->buffer[client->head++] = *event;
  61         client->head &= client->bufsize - 1;
  62         spin_unlock(&client->buffer_lock);
  63
  64         if (event->type == EV_SYN)
  65                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
  66 }
  67
  68 /*
  69  * Pass incoming event to all connected clients.
  70  */
  71 static void evdev_event(struct input_handle *handle,
  72                         unsigned int type, unsigned int code, int value)
  73 {
  74         struct evdev *evdev = handle->private;
  75         struct evdev_client *client;
  76         struct input_event event;
  77
  78         do_gettimeofday(&event.time);
  79         event.type = type;
  80         event.code = code;
  81         event.value = value;
  82
  83         rcu_read_lock();
  84
  85         client = rcu_dereference(evdev->grab);
  86         if (client)
  87                 evdev_pass_event(client, &event);
  88         else
  89                 list_for_each_entry_rcu(client, &evdev->client_list, node)
  90                         evdev_pass_event(client, &event);
  91
  92         rcu_read_unlock();
  93
  94         wake_up_interruptible(&evdev->wait);
  95 }
  96
  97 static int evdev_fasync(int fd, struct file *file, int on)
  98 {
  99         struct evdev_client *client = file->private_data;
 100
 101         return fasync_helper(fd, file, on, &client->fasync);
 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 unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 248 {
 249         unsigned int n_events =
 250                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 251                     EVDEV_MIN_BUFFER_SIZE);
 252
 253         return roundup_pow_of_two(n_events);
 254 }
 255
 256 static int evdev_open(struct inode *inode, struct file *file)
 257 {
 258         struct evdev *evdev;
 259         struct evdev_client *client;
 260         int i = iminor(inode) - EVDEV_MINOR_BASE;
 261         unsigned int bufsize;
 262         int error;
 263
 264         if (i >= EVDEV_MINORS)
 265                 return -ENODEV;
 266
 267         error = mutex_lock_interruptible(&evdev_table_mutex);
 268         if (error)
 269                 return error;
 270         evdev = evdev_table[i];
 271         if (evdev)
 272                 get_device(&evdev->dev);
 273         mutex_unlock(&evdev_table_mutex);
 274
 275         if (!evdev)
 276                 return -ENODEV;
 277
 278         bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 279
 280         client = kzalloc(sizeof(struct evdev_client) +
 281                                 bufsize * sizeof(struct input_event),
 282                          GFP_KERNEL);
 283         if (!client) {
 284                 error = -ENOMEM;
 285                 goto err_put_evdev;
 286         }
 287
 288         client->bufsize = bufsize;
 289         spin_lock_init(&client->buffer_lock);
 290         client->evdev = evdev;
 291         evdev_attach_client(evdev, client);
 292
 293         error = evdev_open_device(evdev);
 294         if (error)
 295                 goto err_free_client;
 296
 297         file->private_data = client;
 298         nonseekable_open(inode, file);
 299
 300         return 0;
 301
 302  err_free_client:
 303         evdev_detach_client(evdev, client);
 304         kfree(client);
 305  err_put_evdev:
 306         put_device(&evdev->dev);
 307         return error;
 308 }
 309
 310 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 311                            size_t count, loff_t *ppos)
 312 {
 313         struct evdev_client *client = file->private_data;
 314         struct evdev *evdev = client->evdev;
 315         struct input_event event;
 316         int retval;
 317
 318         retval = mutex_lock_interruptible(&evdev->mutex);
 319         if (retval)
 320                 return retval;
 321
 322         if (!evdev->exist) {
 323                 retval = -ENODEV;
 324                 goto out;
 325         }
 326
 327         while (retval < count) {
 328
 329                 if (input_event_from_user(buffer + retval, &event)) {
 330                         retval = -EFAULT;
 331                         goto out;
 332                 }
 333
 334                 input_inject_event(&evdev->handle,
 335                                    event.type, event.code, event.value);
 336                 retval += input_event_size();
 337         }
 338
 339  out:
 340         mutex_unlock(&evdev->mutex);
 341         return retval;
 342 }
 343
 344 static int evdev_fetch_next_event(struct evdev_client *client,
 345                                   struct input_event *event)
 346 {
 347         int have_event;
 348
 349         spin_lock_irq(&client->buffer_lock);
 350
 351         have_event = client->head != client->tail;
 352         if (have_event) {
 353                 *event = client->buffer[client->tail++];
 354                 client->tail &= client->bufsize - 1;
 355         }
 356
 357         spin_unlock_irq(&client->buffer_lock);
 358
 359         return have_event;
 360 }
 361
 362 static ssize_t evdev_read(struct file *file, char __user *buffer,
 363                           size_t count, loff_t *ppos)
 364 {
 365         struct evdev_client *client = file->private_data;
 366         struct evdev *evdev = client->evdev;
 367         struct input_event event;
 368         int retval;
 369
 370         if (count < input_event_size())
 371                 return -EINVAL;
 372
 373         if (client->head == client->tail && evdev->exist &&
 374             (file->f_flags & O_NONBLOCK))
 375                 return -EAGAIN;
 376
 377         retval = wait_event_interruptible(evdev->wait,
 378                 client->head != client->tail || !evdev->exist);
 379         if (retval)
 380                 return retval;
 381
 382         if (!evdev->exist)
 383                 return -ENODEV;
 384
 385         while (retval + input_event_size() <= count &&
 386                evdev_fetch_next_event(client, &event)) {
 387
 388                 if (input_event_to_user(buffer + retval, &event))
 389                         return -EFAULT;
 390
 391                 retval += input_event_size();
 392         }
 393
 394         return retval;
 395 }
 396
 397 /* No kernel lock - fine */
 398 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 399 {
 400         struct evdev_client *client = file->private_data;
 401         struct evdev *evdev = client->evdev;
 402
 403         poll_wait(file, &evdev->wait, wait);
 404         return ((client->head == client->tail) ? 0 : (POLLIN | POLLRDNORM)) |
 405                 (evdev->exist ? 0 : (POLLHUP | POLLERR));
 406 }
 407
 408 #ifdef CONFIG_COMPAT
 409
 410 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 411 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 412
 413 #ifdef __BIG_ENDIAN
 414 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 415                         unsigned int maxlen, void __user *p, int compat)
 416 {
 417         int len, i;
 418
 419         if (compat) {
 420                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 421                 if (len > maxlen)
 422                         len = maxlen;
 423
 424                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 425                         if (copy_to_user((compat_long_t __user *) p + i,
 426                                          (compat_long_t *) bits +
 427                                                 i + 1 - ((i % 2) << 1),
 428                                          sizeof(compat_long_t)))
 429                                 return -EFAULT;
 430         } else {
 431                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 432                 if (len > maxlen)
 433                         len = maxlen;
 434
 435                 if (copy_to_user(p, bits, len))
 436                         return -EFAULT;
 437         }
 438
 439         return len;
 440 }
 441 #else
 442 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 443                         unsigned int maxlen, void __user *p, int compat)
 444 {
 445         int len = compat ?
 446                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 447                         BITS_TO_LONGS(maxbit) * sizeof(long);
 448
 449         if (len > maxlen)
 450                 len = maxlen;
 451
 452         return copy_to_user(p, bits, len) ? -EFAULT : len;
 453 }
 454 #endif /* __BIG_ENDIAN */
 455
 456 #else
 457
 458 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 459                         unsigned int maxlen, void __user *p, int compat)
 460 {
 461         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 462
 463         if (len > maxlen)
 464                 len = maxlen;
 465
 466         return copy_to_user(p, bits, len) ? -EFAULT : len;
 467 }
 468
 469 #endif /* CONFIG_COMPAT */
 470
 471 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 472 {
 473         int len;
 474
 475         if (!str)
 476                 return -ENOENT;
 477
 478         len = strlen(str) + 1;
 479         if (len > maxlen)
 480                 len = maxlen;
 481
 482         return copy_to_user(p, str, len) ? -EFAULT : len;
 483 }
 484
 485 #define OLD_KEY_MAX     0x1ff
 486 static int handle_eviocgbit(struct input_dev *dev, unsigned int cmd, void __user *p, int compat_mode)
 487 {
 488         static unsigned long keymax_warn_time;
 489         unsigned long *bits;
 490         int len;
 491
 492         switch (_IOC_NR(cmd) & EV_MAX) {
 493
 494         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 495         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 496         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 497         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 498         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 499         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 500         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 501         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 502         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 503         default: return -EINVAL;
 504         }
 505
 506         /*
 507          * Work around bugs in userspace programs that like to do
 508          * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
 509          * should be in bytes, not in bits.
 510          */
 511         if ((_IOC_NR(cmd) & EV_MAX) == EV_KEY && _IOC_SIZE(cmd) == OLD_KEY_MAX) {
 512                 len = OLD_KEY_MAX;
 513                 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
 514                         printk(KERN_WARNING
 515                                 "evdev.c(EVIOCGBIT): Suspicious buffer size %u, "
 516                                 "limiting output to %zu bytes. See "
 517                                 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
 518                                 OLD_KEY_MAX,
 519                                 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
 520         }
 521
 522         return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
 523 }
 524 #undef OLD_KEY_MAX
 525
 526 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 527                            void __user *p, int compat_mode)
 528 {
 529         struct evdev_client *client = file->private_data;
 530         struct evdev *evdev = client->evdev;
 531         struct input_dev *dev = evdev->handle.dev;
 532         struct input_absinfo abs;
 533         struct ff_effect effect;
 534         int __user *ip = (int __user *)p;
 535         unsigned int i, t, u, v;
 536         int error;
 537
 538         switch (cmd) {
 539
 540         case EVIOCGVERSION:
 541                 return put_user(EV_VERSION, ip);
 542
 543         case EVIOCGID:
 544                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 545                         return -EFAULT;
 546                 return 0;
 547
 548         case EVIOCGREP:
 549                 if (!test_bit(EV_REP, dev->evbit))
 550                         return -ENOSYS;
 551                 if (put_user(dev->rep[REP_DELAY], ip))
 552                         return -EFAULT;
 553                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 554                         return -EFAULT;
 555                 return 0;
 556
 557         case EVIOCSREP:
 558                 if (!test_bit(EV_REP, dev->evbit))
 559                         return -ENOSYS;
 560                 if (get_user(u, ip))
 561                         return -EFAULT;
 562                 if (get_user(v, ip + 1))
 563                         return -EFAULT;
 564
 565                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 566                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 567
 568                 return 0;
 569
 570         case EVIOCGKEYCODE:
 571                 if (get_user(t, ip))
 572                         return -EFAULT;
 573
 574                 error = input_get_keycode(dev, t, &v);
 575                 if (error)
 576                         return error;
 577
 578                 if (put_user(v, ip + 1))
 579                         return -EFAULT;
 580
 581                 return 0;
 582
 583         case EVIOCSKEYCODE:
 584                 if (get_user(t, ip) || get_user(v, ip + 1))
 585                         return -EFAULT;
 586
 587                 return input_set_keycode(dev, t, v);
 588
 589         case EVIOCRMFF:
 590                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 591
 592         case EVIOCGEFFECTS:
 593                 i = test_bit(EV_FF, dev->evbit) ?
 594                                 dev->ff->max_effects : 0;
 595                 if (put_user(i, ip))
 596                         return -EFAULT;
 597                 return 0;
 598
 599         case EVIOCGRAB:
 600                 if (p)
 601                         return evdev_grab(evdev, client);
 602                 else
 603                         return evdev_ungrab(evdev, client);
 604
 605         default:
 606
 607                 if (_IOC_TYPE(cmd) != 'E')
 608                         return -EINVAL;
 609
 610                 if (_IOC_DIR(cmd) == _IOC_READ) {
 611
 612                         if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
 613                                 return handle_eviocgbit(dev, cmd, p, compat_mode);
 614
 615                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))
 616                                 return bits_to_user(dev->key, KEY_MAX, _IOC_SIZE(cmd),
 617                                                     p, compat_mode);
 618
 619                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGLED(0)))
 620                                 return bits_to_user(dev->led, LED_MAX, _IOC_SIZE(cmd),
 621                                                     p, compat_mode);
 622
 623                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSND(0)))
 624                                 return bits_to_user(dev->snd, SND_MAX, _IOC_SIZE(cmd),
 625                                                     p, compat_mode);
 626
 627                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSW(0)))
 628                                 return bits_to_user(dev->sw, SW_MAX, _IOC_SIZE(cmd),
 629                                                     p, compat_mode);
 630
 631                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGNAME(0)))
 632                                 return str_to_user(dev->name, _IOC_SIZE(cmd), p);
 633
 634                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGPHYS(0)))
 635                                 return str_to_user(dev->phys, _IOC_SIZE(cmd), p);
 636
 637                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGUNIQ(0)))
 638                                 return str_to_user(dev->uniq, _IOC_SIZE(cmd), p);
 639
 640                         if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 641
 642                                 t = _IOC_NR(cmd) & ABS_MAX;
 643
 644                                 abs.value = dev->abs[t];
 645                                 abs.minimum = dev->absmin[t];
 646                                 abs.maximum = dev->absmax[t];
 647                                 abs.fuzz = dev->absfuzz[t];
 648                                 abs.flat = dev->absflat[t];
 649                                 abs.resolution = dev->absres[t];
 650
 651                                 if (copy_to_user(p, &abs, min_t(size_t,
 652                                                                 _IOC_SIZE(cmd),
 653                                                                 sizeof(struct input_absinfo))))
 654                                         return -EFAULT;
 655
 656                                 return 0;
 657                         }
 658
 659                 }
 660
 661                 if (_IOC_DIR(cmd) == _IOC_WRITE) {
 662
 663                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCSFF)) {
 664
 665                                 if (input_ff_effect_from_user(p, _IOC_SIZE(cmd), &effect))
 666                                         return -EFAULT;
 667
 668                                 error = input_ff_upload(dev, &effect, file);
 669
 670                                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 671                                         return -EFAULT;
 672
 673                                 return error;
 674                         }
 675
 676                         if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 677
 678                                 t = _IOC_NR(cmd) & ABS_MAX;
 679
 680                                 if (copy_from_user(&abs, p, min_t(size_t,
 681                                                                   _IOC_SIZE(cmd),
 682                                                                   sizeof(struct input_absinfo))))
 683                                         return -EFAULT;
 684
 685                                 /*
 686                                  * Take event lock to ensure that we are not
 687                                  * changing device parameters in the middle
 688                                  * of event.
 689                                  */
 690                                 spin_lock_irq(&dev->event_lock);
 691
 692                                 dev->abs[t] = abs.value;
 693                                 dev->absmin[t] = abs.minimum;
 694                                 dev->absmax[t] = abs.maximum;
 695                                 dev->absfuzz[t] = abs.fuzz;
 696                                 dev->absflat[t] = abs.flat;
 697                                 dev->absres[t] = _IOC_SIZE(cmd) < sizeof(struct input_absinfo) ?
 698                                                         0 : abs.resolution;
 699
 700                                 spin_unlock_irq(&dev->event_lock);
 701
 702                                 return 0;
 703                         }
 704                 }
 705         }
 706         return -EINVAL;
 707 }
 708
 709 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 710                                 void __user *p, int compat_mode)
 711 {
 712         struct evdev_client *client = file->private_data;
 713         struct evdev *evdev = client->evdev;
 714         int retval;
 715
 716         retval = mutex_lock_interruptible(&evdev->mutex);
 717         if (retval)
 718                 return retval;
 719
 720         if (!evdev->exist) {
 721                 retval = -ENODEV;
 722                 goto out;
 723         }
 724
 725         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
 726
 727  out:
 728         mutex_unlock(&evdev->mutex);
 729         return retval;
 730 }
 731
 732 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 733 {
 734         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
 735 }
 736
 737 #ifdef CONFIG_COMPAT
 738 static long evdev_ioctl_compat(struct file *file,
 739                                 unsigned int cmd, unsigned long arg)
 740 {
 741         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
 742 }
 743 #endif
 744
 745 static const struct file_operations evdev_fops = {
 746         .owner          = THIS_MODULE,
 747         .read           = evdev_read,
 748         .write          = evdev_write,
 749         .poll           = evdev_poll,
 750         .open           = evdev_open,
 751         .release        = evdev_release,
 752         .unlocked_ioctl = evdev_ioctl,
 753 #ifdef CONFIG_COMPAT
 754         .compat_ioctl   = evdev_ioctl_compat,
 755 #endif
 756         .fasync         = evdev_fasync,
 757         .flush          = evdev_flush
 758 };
 759
 760 static int evdev_install_chrdev(struct evdev *evdev)
 761 {
 762         /*
 763          * No need to do any locking here as calls to connect and
 764          * disconnect are serialized by the input core
 765          */
 766         evdev_table[evdev->minor] = evdev;
 767         return 0;
 768 }
 769
 770 static void evdev_remove_chrdev(struct evdev *evdev)
 771 {
 772         /*
 773          * Lock evdev table to prevent race with evdev_open()
 774          */
 775         mutex_lock(&evdev_table_mutex);
 776         evdev_table[evdev->minor] = NULL;
 777         mutex_unlock(&evdev_table_mutex);
 778 }
 779
 780 /*
 781  * Mark device non-existent. This disables writes, ioctls and
 782  * prevents new users from opening the device. Already posted
 783  * blocking reads will stay, however new ones will fail.
 784  */
 785 static void evdev_mark_dead(struct evdev *evdev)
 786 {
 787         mutex_lock(&evdev->mutex);
 788         evdev->exist = 0;
 789         mutex_unlock(&evdev->mutex);
 790 }
 791
 792 static void evdev_cleanup(struct evdev *evdev)
 793 {
 794         struct input_handle *handle = &evdev->handle;
 795
 796         evdev_mark_dead(evdev);
 797         evdev_hangup(evdev);
 798         evdev_remove_chrdev(evdev);
 799
 800         /* evdev is marked dead so no one else accesses evdev->open */
 801         if (evdev->open) {
 802                 input_flush_device(handle, NULL);
 803                 input_close_device(handle);
 804         }
 805 }
 806
 807 /*
 808  * Create new evdev device. Note that input core serializes calls
 809  * to connect and disconnect so we don't need to lock evdev_table here.
 810  */
 811 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
 812                          const struct input_device_id *id)
 813 {
 814         struct evdev *evdev;
 815         int minor;
 816         int error;
 817
 818         for (minor = 0; minor < EVDEV_MINORS; minor++)
 819                 if (!evdev_table[minor])
 820                         break;
 821
 822         if (minor == EVDEV_MINORS) {
 823                 printk(KERN_ERR "evdev: no more free evdev devices\n");
 824                 return -ENFILE;
 825         }
 826
 827         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
 828         if (!evdev)
 829                 return -ENOMEM;
 830
 831         INIT_LIST_HEAD(&evdev->client_list);
 832         spin_lock_init(&evdev->client_lock);
 833         mutex_init(&evdev->mutex);
 834         init_waitqueue_head(&evdev->wait);
 835
 836         dev_set_name(&evdev->dev, "event%d", minor);
 837         evdev->exist = 1;
 838         evdev->minor = minor;
 839
 840         evdev->handle.dev = input_get_device(dev);
 841         evdev->handle.name = dev_name(&evdev->dev);
 842         evdev->handle.handler = handler;
 843         evdev->handle.private = evdev;
 844
 845         evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 846         evdev->dev.class = &input_class;
 847         evdev->dev.parent = &dev->dev;
 848         evdev->dev.release = evdev_free;
 849         device_initialize(&evdev->dev);
 850
 851         error = input_register_handle(&evdev->handle);
 852         if (error)
 853                 goto err_free_evdev;
 854
 855         error = evdev_install_chrdev(evdev);
 856         if (error)
 857                 goto err_unregister_handle;
 858
 859         error = device_add(&evdev->dev);
 860         if (error)
 861                 goto err_cleanup_evdev;
 862
 863         return 0;
 864
 865  err_cleanup_evdev:
 866         evdev_cleanup(evdev);
 867  err_unregister_handle:
 868         input_unregister_handle(&evdev->handle);
 869  err_free_evdev:
 870         put_device(&evdev->dev);
 871         return error;
 872 }
 873
 874 static void evdev_disconnect(struct input_handle *handle)
 875 {
 876         struct evdev *evdev = handle->private;
 877
 878         device_del(&evdev->dev);
 879         evdev_cleanup(evdev);
 880         input_unregister_handle(handle);
 881         put_device(&evdev->dev);
 882 }
 883
 884 static const struct input_device_id evdev_ids[] = {
 885         { .driver_info = 1 },   /* Matches all devices */
 886         { },                    /* Terminating zero entry */
 887 };
 888
 889 MODULE_DEVICE_TABLE(input, evdev_ids);
 890
 891 static struct input_handler evdev_handler = {
 892         .event          = evdev_event,
 893         .connect        = evdev_connect,
 894         .disconnect     = evdev_disconnect,
 895         .fops           = &evdev_fops,
 896         .minor          = EVDEV_MINOR_BASE,
 897         .name           = "evdev",
 898         .id_table       = evdev_ids,
 899 };
 900
 901 static int __init evdev_init(void)
 902 {
 903         return input_register_handler(&evdev_handler);
 904 }
 905
 906 static void __exit evdev_exit(void)
 907 {
 908         input_unregister_handler(&evdev_handler);
 909 }
 910
 911 module_init(evdev_init);
 912 module_exit(evdev_exit);
 913
 914 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
 915 MODULE_DESCRIPTION("Input driver event char devices");
 916 MODULE_LICENSE("GPL");