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 pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #define EVDEV_MINOR_BASE        64
  14 #define EVDEV_MINORS            32
  15 #define EVDEV_MIN_BUFFER_SIZE   64U
  16 #define EVDEV_BUF_PACKETS       8
  17
  18 #include <linux/poll.h>
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/input.h>
  24 #include <linux/major.h>
  25 #include <linux/device.h>
  26 #include "input-compat.h"
  27
  28 struct evdev {
  29         int open;
  30         int minor;
  31         struct input_handle handle;
  32         wait_queue_head_t wait;
  33         struct evdev_client __rcu *grab;
  34         struct list_head client_list;
  35         spinlock_t client_lock; /* protects client_list */
  36         struct mutex mutex;
  37         struct device dev;
  38         bool exist;
  39 };
  40
  41 struct evdev_client {
  42         unsigned int head;
  43         unsigned int tail;
  44         unsigned int packet_head; /* [future] position of the first element of next packet */
  45         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  46         struct fasync_struct *fasync;
  47         struct evdev *evdev;
  48         struct list_head node;
  49         int clkid;
  50         unsigned int bufsize;
  51         struct input_event buffer[];
  52 };
  53
  54 static struct evdev *evdev_table[EVDEV_MINORS];
  55 static DEFINE_MUTEX(evdev_table_mutex);
  56
  57 static void evdev_pass_event(struct evdev_client *client,
  58                              struct input_event *event,
  59                              ktime_t mono, ktime_t real)
  60 {
  61         event->time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ?
  62                                         mono : real);
  63
  64         /* Interrupts are disabled, just acquire the lock. */
  65         spin_lock(&client->buffer_lock);
  66
  67         client->buffer[client->head++] = *event;
  68         client->head &= client->bufsize - 1;
  69
  70         if (unlikely(client->head == client->tail)) {
  71                 /*
  72                  * This effectively "drops" all unconsumed events, leaving
  73                  * EV_SYN/SYN_DROPPED plus the newest event in the queue.
  74                  */
  75                 client->tail = (client->head - 2) & (client->bufsize - 1);
  76
  77                 client->buffer[client->tail].time = event->time;
  78                 client->buffer[client->tail].type = EV_SYN;
  79                 client->buffer[client->tail].code = SYN_DROPPED;
  80                 client->buffer[client->tail].value = 0;
  81
  82                 client->packet_head = client->tail;
  83         }
  84
  85         if (event->type == EV_SYN && event->code == SYN_REPORT) {
  86                 client->packet_head = client->head;
  87                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
  88         }
  89
  90         spin_unlock(&client->buffer_lock);
  91 }
  92
  93 /*
  94  * Pass incoming event to all connected clients.
  95  */
  96 static void evdev_event(struct input_handle *handle,
  97                         unsigned int type, unsigned int code, int value)
  98 {
  99         struct evdev *evdev = handle->private;
 100         struct evdev_client *client;
 101         struct input_event event;
 102         ktime_t time_mono, time_real;
 103
 104         time_mono = ktime_get();
 105         time_real = ktime_sub(time_mono, ktime_get_monotonic_offset());
 106
 107         event.type = type;
 108         event.code = code;
 109         event.value = value;
 110
 111         rcu_read_lock();
 112
 113         client = rcu_dereference(evdev->grab);
 114
 115         if (client)
 116                 evdev_pass_event(client, &event, time_mono, time_real);
 117         else
 118                 list_for_each_entry_rcu(client, &evdev->client_list, node)
 119                         evdev_pass_event(client, &event, time_mono, time_real);
 120
 121         rcu_read_unlock();
 122
 123         if (type == EV_SYN && code == SYN_REPORT)
 124                 wake_up_interruptible(&evdev->wait);
 125 }
 126
 127 static int evdev_fasync(int fd, struct file *file, int on)
 128 {
 129         struct evdev_client *client = file->private_data;
 130
 131         return fasync_helper(fd, file, on, &client->fasync);
 132 }
 133
 134 static int evdev_flush(struct file *file, fl_owner_t id)
 135 {
 136         struct evdev_client *client = file->private_data;
 137         struct evdev *evdev = client->evdev;
 138         int retval;
 139
 140         retval = mutex_lock_interruptible(&evdev->mutex);
 141         if (retval)
 142                 return retval;
 143
 144         if (!evdev->exist)
 145                 retval = -ENODEV;
 146         else
 147                 retval = input_flush_device(&evdev->handle, file);
 148
 149         mutex_unlock(&evdev->mutex);
 150         return retval;
 151 }
 152
 153 static void evdev_free(struct device *dev)
 154 {
 155         struct evdev *evdev = container_of(dev, struct evdev, dev);
 156
 157         input_put_device(evdev->handle.dev);
 158         kfree(evdev);
 159 }
 160
 161 /*
 162  * Grabs an event device (along with underlying input device).
 163  * This function is called with evdev->mutex taken.
 164  */
 165 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 166 {
 167         int error;
 168
 169         if (evdev->grab)
 170                 return -EBUSY;
 171
 172         error = input_grab_device(&evdev->handle);
 173         if (error)
 174                 return error;
 175
 176         rcu_assign_pointer(evdev->grab, client);
 177
 178         return 0;
 179 }
 180
 181 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 182 {
 183         if (evdev->grab != client)
 184                 return  -EINVAL;
 185
 186         rcu_assign_pointer(evdev->grab, NULL);
 187         synchronize_rcu();
 188         input_release_device(&evdev->handle);
 189
 190         return 0;
 191 }
 192
 193 static void evdev_attach_client(struct evdev *evdev,
 194                                 struct evdev_client *client)
 195 {
 196         spin_lock(&evdev->client_lock);
 197         list_add_tail_rcu(&client->node, &evdev->client_list);
 198         spin_unlock(&evdev->client_lock);
 199 }
 200
 201 static void evdev_detach_client(struct evdev *evdev,
 202                                 struct evdev_client *client)
 203 {
 204         spin_lock(&evdev->client_lock);
 205         list_del_rcu(&client->node);
 206         spin_unlock(&evdev->client_lock);
 207         synchronize_rcu();
 208 }
 209
 210 static int evdev_open_device(struct evdev *evdev)
 211 {
 212         int retval;
 213
 214         retval = mutex_lock_interruptible(&evdev->mutex);
 215         if (retval)
 216                 return retval;
 217
 218         if (!evdev->exist)
 219                 retval = -ENODEV;
 220         else if (!evdev->open++) {
 221                 retval = input_open_device(&evdev->handle);
 222                 if (retval)
 223                         evdev->open--;
 224         }
 225
 226         mutex_unlock(&evdev->mutex);
 227         return retval;
 228 }
 229
 230 static void evdev_close_device(struct evdev *evdev)
 231 {
 232         mutex_lock(&evdev->mutex);
 233
 234         if (evdev->exist && !--evdev->open)
 235                 input_close_device(&evdev->handle);
 236
 237         mutex_unlock(&evdev->mutex);
 238 }
 239
 240 /*
 241  * Wake up users waiting for IO so they can disconnect from
 242  * dead device.
 243  */
 244 static void evdev_hangup(struct evdev *evdev)
 245 {
 246         struct evdev_client *client;
 247
 248         spin_lock(&evdev->client_lock);
 249         list_for_each_entry(client, &evdev->client_list, node)
 250                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 251         spin_unlock(&evdev->client_lock);
 252
 253         wake_up_interruptible(&evdev->wait);
 254 }
 255
 256 static int evdev_release(struct inode *inode, struct file *file)
 257 {
 258         struct evdev_client *client = file->private_data;
 259         struct evdev *evdev = client->evdev;
 260
 261         mutex_lock(&evdev->mutex);
 262         if (evdev->grab == client)
 263                 evdev_ungrab(evdev, client);
 264         mutex_unlock(&evdev->mutex);
 265
 266         evdev_detach_client(evdev, client);
 267         kfree(client);
 268
 269         evdev_close_device(evdev);
 270         put_device(&evdev->dev);
 271
 272         return 0;
 273 }
 274
 275 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 276 {
 277         unsigned int n_events =
 278                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 279                     EVDEV_MIN_BUFFER_SIZE);
 280
 281         return roundup_pow_of_two(n_events);
 282 }
 283
 284 static int evdev_open(struct inode *inode, struct file *file)
 285 {
 286         struct evdev *evdev;
 287         struct evdev_client *client;
 288         int i = iminor(inode) - EVDEV_MINOR_BASE;
 289         unsigned int bufsize;
 290         int error;
 291
 292         if (i >= EVDEV_MINORS)
 293                 return -ENODEV;
 294
 295         error = mutex_lock_interruptible(&evdev_table_mutex);
 296         if (error)
 297                 return error;
 298         evdev = evdev_table[i];
 299         if (evdev)
 300                 get_device(&evdev->dev);
 301         mutex_unlock(&evdev_table_mutex);
 302
 303         if (!evdev)
 304                 return -ENODEV;
 305
 306         bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 307
 308         client = kzalloc(sizeof(struct evdev_client) +
 309                                 bufsize * sizeof(struct input_event),
 310                          GFP_KERNEL);
 311         if (!client) {
 312                 error = -ENOMEM;
 313                 goto err_put_evdev;
 314         }
 315
 316         client->bufsize = bufsize;
 317         spin_lock_init(&client->buffer_lock);
 318         client->evdev = evdev;
 319         evdev_attach_client(evdev, client);
 320
 321         error = evdev_open_device(evdev);
 322         if (error)
 323                 goto err_free_client;
 324
 325         file->private_data = client;
 326         nonseekable_open(inode, file);
 327
 328         return 0;
 329
 330  err_free_client:
 331         evdev_detach_client(evdev, client);
 332         kfree(client);
 333  err_put_evdev:
 334         put_device(&evdev->dev);
 335         return error;
 336 }
 337
 338 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 339                            size_t count, loff_t *ppos)
 340 {
 341         struct evdev_client *client = file->private_data;
 342         struct evdev *evdev = client->evdev;
 343         struct input_event event;
 344         int retval;
 345
 346         if (count < input_event_size())
 347                 return -EINVAL;
 348
 349         retval = mutex_lock_interruptible(&evdev->mutex);
 350         if (retval)
 351                 return retval;
 352
 353         if (!evdev->exist) {
 354                 retval = -ENODEV;
 355                 goto out;
 356         }
 357
 358         do {
 359                 if (input_event_from_user(buffer + retval, &event)) {
 360                         retval = -EFAULT;
 361                         goto out;
 362                 }
 363                 retval += input_event_size();
 364
 365                 input_inject_event(&evdev->handle,
 366                                    event.type, event.code, event.value);
 367         } while (retval + input_event_size() <= count);
 368
 369  out:
 370         mutex_unlock(&evdev->mutex);
 371         return retval;
 372 }
 373
 374 static int evdev_fetch_next_event(struct evdev_client *client,
 375                                   struct input_event *event)
 376 {
 377         int have_event;
 378
 379         spin_lock_irq(&client->buffer_lock);
 380
 381         have_event = client->packet_head != client->tail;
 382         if (have_event) {
 383                 *event = client->buffer[client->tail++];
 384                 client->tail &= client->bufsize - 1;
 385         }
 386
 387         spin_unlock_irq(&client->buffer_lock);
 388
 389         return have_event;
 390 }
 391
 392 static ssize_t evdev_read(struct file *file, char __user *buffer,
 393                           size_t count, loff_t *ppos)
 394 {
 395         struct evdev_client *client = file->private_data;
 396         struct evdev *evdev = client->evdev;
 397         struct input_event event;
 398         int retval = 0;
 399
 400         if (count < input_event_size())
 401                 return -EINVAL;
 402
 403         if (!(file->f_flags & O_NONBLOCK)) {
 404                 retval = wait_event_interruptible(evdev->wait,
 405                                 client->packet_head != client->tail ||
 406                                 !evdev->exist);
 407                 if (retval)
 408                         return retval;
 409         }
 410
 411         if (!evdev->exist)
 412                 return -ENODEV;
 413
 414         while (retval + input_event_size() <= count &&
 415                evdev_fetch_next_event(client, &event)) {
 416
 417                 if (input_event_to_user(buffer + retval, &event))
 418                         return -EFAULT;
 419
 420                 retval += input_event_size();
 421         }
 422
 423         if (retval == 0 && (file->f_flags & O_NONBLOCK))
 424                 return -EAGAIN;
 425
 426         return retval;
 427 }
 428
 429 /* No kernel lock - fine */
 430 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 431 {
 432         struct evdev_client *client = file->private_data;
 433         struct evdev *evdev = client->evdev;
 434         unsigned int mask;
 435
 436         poll_wait(file, &evdev->wait, wait);
 437
 438         mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
 439         if (client->packet_head != client->tail)
 440                 mask |= POLLIN | POLLRDNORM;
 441
 442         return mask;
 443 }
 444
 445 #ifdef CONFIG_COMPAT
 446
 447 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 448 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 449
 450 #ifdef __BIG_ENDIAN
 451 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 452                         unsigned int maxlen, void __user *p, int compat)
 453 {
 454         int len, i;
 455
 456         if (compat) {
 457                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 458                 if (len > maxlen)
 459                         len = maxlen;
 460
 461                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 462                         if (copy_to_user((compat_long_t __user *) p + i,
 463                                          (compat_long_t *) bits +
 464                                                 i + 1 - ((i % 2) << 1),
 465                                          sizeof(compat_long_t)))
 466                                 return -EFAULT;
 467         } else {
 468                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 469                 if (len > maxlen)
 470                         len = maxlen;
 471
 472                 if (copy_to_user(p, bits, len))
 473                         return -EFAULT;
 474         }
 475
 476         return len;
 477 }
 478 #else
 479 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 480                         unsigned int maxlen, void __user *p, int compat)
 481 {
 482         int len = compat ?
 483                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 484                         BITS_TO_LONGS(maxbit) * sizeof(long);
 485
 486         if (len > maxlen)
 487                 len = maxlen;
 488
 489         return copy_to_user(p, bits, len) ? -EFAULT : len;
 490 }
 491 #endif /* __BIG_ENDIAN */
 492
 493 #else
 494
 495 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 496                         unsigned int maxlen, void __user *p, int compat)
 497 {
 498         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 499
 500         if (len > maxlen)
 501                 len = maxlen;
 502
 503         return copy_to_user(p, bits, len) ? -EFAULT : len;
 504 }
 505
 506 #endif /* CONFIG_COMPAT */
 507
 508 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 509 {
 510         int len;
 511
 512         if (!str)
 513                 return -ENOENT;
 514
 515         len = strlen(str) + 1;
 516         if (len > maxlen)
 517                 len = maxlen;
 518
 519         return copy_to_user(p, str, len) ? -EFAULT : len;
 520 }
 521
 522 #define OLD_KEY_MAX     0x1ff
 523 static int handle_eviocgbit(struct input_dev *dev,
 524                             unsigned int type, unsigned int size,
 525                             void __user *p, int compat_mode)
 526 {
 527         static unsigned long keymax_warn_time;
 528         unsigned long *bits;
 529         int len;
 530
 531         switch (type) {
 532
 533         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 534         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 535         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 536         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 537         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 538         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 539         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 540         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 541         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 542         default: return -EINVAL;
 543         }
 544
 545         /*
 546          * Work around bugs in userspace programs that like to do
 547          * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
 548          * should be in bytes, not in bits.
 549          */
 550         if (type == EV_KEY && size == OLD_KEY_MAX) {
 551                 len = OLD_KEY_MAX;
 552                 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
 553                         pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
 554                                    "limiting output to %zu bytes. See "
 555                                    "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
 556                                    OLD_KEY_MAX,
 557                                    BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
 558         }
 559
 560         return bits_to_user(bits, len, size, p, compat_mode);
 561 }
 562 #undef OLD_KEY_MAX
 563
 564 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
 565 {
 566         struct input_keymap_entry ke = {
 567                 .len    = sizeof(unsigned int),
 568                 .flags  = 0,
 569         };
 570         int __user *ip = (int __user *)p;
 571         int error;
 572
 573         /* legacy case */
 574         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 575                 return -EFAULT;
 576
 577         error = input_get_keycode(dev, &ke);
 578         if (error)
 579                 return error;
 580
 581         if (put_user(ke.keycode, ip + 1))
 582                 return -EFAULT;
 583
 584         return 0;
 585 }
 586
 587 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
 588 {
 589         struct input_keymap_entry ke;
 590         int error;
 591
 592         if (copy_from_user(&ke, p, sizeof(ke)))
 593                 return -EFAULT;
 594
 595         error = input_get_keycode(dev, &ke);
 596         if (error)
 597                 return error;
 598
 599         if (copy_to_user(p, &ke, sizeof(ke)))
 600                 return -EFAULT;
 601
 602         return 0;
 603 }
 604
 605 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
 606 {
 607         struct input_keymap_entry ke = {
 608                 .len    = sizeof(unsigned int),
 609                 .flags  = 0,
 610         };
 611         int __user *ip = (int __user *)p;
 612
 613         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 614                 return -EFAULT;
 615
 616         if (get_user(ke.keycode, ip + 1))
 617                 return -EFAULT;
 618
 619         return input_set_keycode(dev, &ke);
 620 }
 621
 622 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
 623 {
 624         struct input_keymap_entry ke;
 625
 626         if (copy_from_user(&ke, p, sizeof(ke)))
 627                 return -EFAULT;
 628
 629         if (ke.len > sizeof(ke.scancode))
 630                 return -EINVAL;
 631
 632         return input_set_keycode(dev, &ke);
 633 }
 634
 635 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 636                            void __user *p, int compat_mode)
 637 {
 638         struct evdev_client *client = file->private_data;
 639         struct evdev *evdev = client->evdev;
 640         struct input_dev *dev = evdev->handle.dev;
 641         struct input_absinfo abs;
 642         struct ff_effect effect;
 643         int __user *ip = (int __user *)p;
 644         unsigned int i, t, u, v;
 645         unsigned int size;
 646         int error;
 647
 648         /* First we check for fixed-length commands */
 649         switch (cmd) {
 650
 651         case EVIOCGVERSION:
 652                 return put_user(EV_VERSION, ip);
 653
 654         case EVIOCGID:
 655                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 656                         return -EFAULT;
 657                 return 0;
 658
 659         case EVIOCGREP:
 660                 if (!test_bit(EV_REP, dev->evbit))
 661                         return -ENOSYS;
 662                 if (put_user(dev->rep[REP_DELAY], ip))
 663                         return -EFAULT;
 664                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 665                         return -EFAULT;
 666                 return 0;
 667
 668         case EVIOCSREP:
 669                 if (!test_bit(EV_REP, dev->evbit))
 670                         return -ENOSYS;
 671                 if (get_user(u, ip))
 672                         return -EFAULT;
 673                 if (get_user(v, ip + 1))
 674                         return -EFAULT;
 675
 676                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 677                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 678
 679                 return 0;
 680
 681         case EVIOCRMFF:
 682                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 683
 684         case EVIOCGEFFECTS:
 685                 i = test_bit(EV_FF, dev->evbit) ?
 686                                 dev->ff->max_effects : 0;
 687                 if (put_user(i, ip))
 688                         return -EFAULT;
 689                 return 0;
 690
 691         case EVIOCGRAB:
 692                 if (p)
 693                         return evdev_grab(evdev, client);
 694                 else
 695                         return evdev_ungrab(evdev, client);
 696
 697         case EVIOCSCLOCKID:
 698                 if (copy_from_user(&i, p, sizeof(unsigned int)))
 699                         return -EFAULT;
 700                 if (i != CLOCK_MONOTONIC && i != CLOCK_REALTIME)
 701                         return -EINVAL;
 702                 client->clkid = i;
 703                 return 0;
 704
 705         case EVIOCGKEYCODE:
 706                 return evdev_handle_get_keycode(dev, p);
 707
 708         case EVIOCSKEYCODE:
 709                 return evdev_handle_set_keycode(dev, p);
 710
 711         case EVIOCGKEYCODE_V2:
 712                 return evdev_handle_get_keycode_v2(dev, p);
 713
 714         case EVIOCSKEYCODE_V2:
 715                 return evdev_handle_set_keycode_v2(dev, p);
 716         }
 717
 718         size = _IOC_SIZE(cmd);
 719
 720         /* Now check variable-length commands */
 721 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
 722         switch (EVIOC_MASK_SIZE(cmd)) {
 723
 724         case EVIOCGPROP(0):
 725                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
 726                                     size, p, compat_mode);
 727
 728         case EVIOCGKEY(0):
 729                 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
 730
 731         case EVIOCGLED(0):
 732                 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode);
 733
 734         case EVIOCGSND(0):
 735                 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode);
 736
 737         case EVIOCGSW(0):
 738                 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode);
 739
 740         case EVIOCGNAME(0):
 741                 return str_to_user(dev->name, size, p);
 742
 743         case EVIOCGPHYS(0):
 744                 return str_to_user(dev->phys, size, p);
 745
 746         case EVIOCGUNIQ(0):
 747                 return str_to_user(dev->uniq, size, p);
 748
 749         case EVIOC_MASK_SIZE(EVIOCSFF):
 750                 if (input_ff_effect_from_user(p, size, &effect))
 751                         return -EFAULT;
 752
 753                 error = input_ff_upload(dev, &effect, file);
 754
 755                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 756                         return -EFAULT;
 757
 758                 return error;
 759         }
 760
 761         /* Multi-number variable-length handlers */
 762         if (_IOC_TYPE(cmd) != 'E')
 763                 return -EINVAL;
 764
 765         if (_IOC_DIR(cmd) == _IOC_READ) {
 766
 767                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
 768                         return handle_eviocgbit(dev,
 769                                                 _IOC_NR(cmd) & EV_MAX, size,
 770                                                 p, compat_mode);
 771
 772                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 773
 774                         if (!dev->absinfo)
 775                                 return -EINVAL;
 776
 777                         t = _IOC_NR(cmd) & ABS_MAX;
 778                         abs = dev->absinfo[t];
 779
 780                         if (copy_to_user(p, &abs, min_t(size_t,
 781                                         size, sizeof(struct input_absinfo))))
 782                                 return -EFAULT;
 783
 784                         return 0;
 785                 }
 786         }
 787
 788         if (_IOC_DIR(cmd) == _IOC_WRITE) {
 789
 790                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 791
 792                         if (!dev->absinfo)
 793                                 return -EINVAL;
 794
 795                         t = _IOC_NR(cmd) & ABS_MAX;
 796
 797                         if (copy_from_user(&abs, p, min_t(size_t,
 798                                         size, sizeof(struct input_absinfo))))
 799                                 return -EFAULT;
 800
 801                         if (size < sizeof(struct input_absinfo))
 802                                 abs.resolution = 0;
 803
 804                         /* We can't change number of reserved MT slots */
 805                         if (t == ABS_MT_SLOT)
 806                                 return -EINVAL;
 807
 808                         /*
 809                          * Take event lock to ensure that we are not
 810                          * changing device parameters in the middle
 811                          * of event.
 812                          */
 813                         spin_lock_irq(&dev->event_lock);
 814                         dev->absinfo[t] = abs;
 815                         spin_unlock_irq(&dev->event_lock);
 816
 817                         return 0;
 818                 }
 819         }
 820
 821         return -EINVAL;
 822 }
 823
 824 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 825                                 void __user *p, int compat_mode)
 826 {
 827         struct evdev_client *client = file->private_data;
 828         struct evdev *evdev = client->evdev;
 829         int retval;
 830
 831         retval = mutex_lock_interruptible(&evdev->mutex);
 832         if (retval)
 833                 return retval;
 834
 835         if (!evdev->exist) {
 836                 retval = -ENODEV;
 837                 goto out;
 838         }
 839
 840         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
 841
 842  out:
 843         mutex_unlock(&evdev->mutex);
 844         return retval;
 845 }
 846
 847 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 848 {
 849         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
 850 }
 851
 852 #ifdef CONFIG_COMPAT
 853 static long evdev_ioctl_compat(struct file *file,
 854                                 unsigned int cmd, unsigned long arg)
 855 {
 856         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
 857 }
 858 #endif
 859
 860 static const struct file_operations evdev_fops = {
 861         .owner          = THIS_MODULE,
 862         .read           = evdev_read,
 863         .write          = evdev_write,
 864         .poll           = evdev_poll,
 865         .open           = evdev_open,
 866         .release        = evdev_release,
 867         .unlocked_ioctl = evdev_ioctl,
 868 #ifdef CONFIG_COMPAT
 869         .compat_ioctl   = evdev_ioctl_compat,
 870 #endif
 871         .fasync         = evdev_fasync,
 872         .flush          = evdev_flush,
 873         .llseek         = no_llseek,
 874 };
 875
 876 static int evdev_install_chrdev(struct evdev *evdev)
 877 {
 878         /*
 879          * No need to do any locking here as calls to connect and
 880          * disconnect are serialized by the input core
 881          */
 882         evdev_table[evdev->minor] = evdev;
 883         return 0;
 884 }
 885
 886 static void evdev_remove_chrdev(struct evdev *evdev)
 887 {
 888         /*
 889          * Lock evdev table to prevent race with evdev_open()
 890          */
 891         mutex_lock(&evdev_table_mutex);
 892         evdev_table[evdev->minor] = NULL;
 893         mutex_unlock(&evdev_table_mutex);
 894 }
 895
 896 /*
 897  * Mark device non-existent. This disables writes, ioctls and
 898  * prevents new users from opening the device. Already posted
 899  * blocking reads will stay, however new ones will fail.
 900  */
 901 static void evdev_mark_dead(struct evdev *evdev)
 902 {
 903         mutex_lock(&evdev->mutex);
 904         evdev->exist = false;
 905         mutex_unlock(&evdev->mutex);
 906 }
 907
 908 static void evdev_cleanup(struct evdev *evdev)
 909 {
 910         struct input_handle *handle = &evdev->handle;
 911
 912         evdev_mark_dead(evdev);
 913         evdev_hangup(evdev);
 914         evdev_remove_chrdev(evdev);
 915
 916         /* evdev is marked dead so no one else accesses evdev->open */
 917         if (evdev->open) {
 918                 input_flush_device(handle, NULL);
 919                 input_close_device(handle);
 920         }
 921 }
 922
 923 /*
 924  * Create new evdev device. Note that input core serializes calls
 925  * to connect and disconnect so we don't need to lock evdev_table here.
 926  */
 927 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
 928                          const struct input_device_id *id)
 929 {
 930         struct evdev *evdev;
 931         int minor;
 932         int error;
 933
 934         for (minor = 0; minor < EVDEV_MINORS; minor++)
 935                 if (!evdev_table[minor])
 936                         break;
 937
 938         if (minor == EVDEV_MINORS) {
 939                 pr_err("no more free evdev devices\n");
 940                 return -ENFILE;
 941         }
 942
 943         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
 944         if (!evdev)
 945                 return -ENOMEM;
 946
 947         INIT_LIST_HEAD(&evdev->client_list);
 948         spin_lock_init(&evdev->client_lock);
 949         mutex_init(&evdev->mutex);
 950         init_waitqueue_head(&evdev->wait);
 951
 952         dev_set_name(&evdev->dev, "event%d", minor);
 953         evdev->exist = true;
 954         evdev->minor = minor;
 955
 956         evdev->handle.dev = input_get_device(dev);
 957         evdev->handle.name = dev_name(&evdev->dev);
 958         evdev->handle.handler = handler;
 959         evdev->handle.private = evdev;
 960
 961         evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 962         evdev->dev.class = &input_class;
 963         evdev->dev.parent = &dev->dev;
 964         evdev->dev.release = evdev_free;
 965         device_initialize(&evdev->dev);
 966
 967         error = input_register_handle(&evdev->handle);
 968         if (error)
 969                 goto err_free_evdev;
 970
 971         error = evdev_install_chrdev(evdev);
 972         if (error)
 973                 goto err_unregister_handle;
 974
 975         error = device_add(&evdev->dev);
 976         if (error)
 977                 goto err_cleanup_evdev;
 978
 979         return 0;
 980
 981  err_cleanup_evdev:
 982         evdev_cleanup(evdev);
 983  err_unregister_handle:
 984         input_unregister_handle(&evdev->handle);
 985  err_free_evdev:
 986         put_device(&evdev->dev);
 987         return error;
 988 }
 989
 990 static void evdev_disconnect(struct input_handle *handle)
 991 {
 992         struct evdev *evdev = handle->private;
 993
 994         device_del(&evdev->dev);
 995         evdev_cleanup(evdev);
 996         input_unregister_handle(handle);
 997         put_device(&evdev->dev);
 998 }
 999
1000 static const struct input_device_id evdev_ids[] = {
1001         { .driver_info = 1 },   /* Matches all devices */
1002         { },                    /* Terminating zero entry */
1003 };
1004
1005 MODULE_DEVICE_TABLE(input, evdev_ids);
1006
1007 static struct input_handler evdev_handler = {
1008         .event          = evdev_event,
1009         .connect        = evdev_connect,
1010         .disconnect     = evdev_disconnect,
1011         .fops           = &evdev_fops,
1012         .minor          = EVDEV_MINOR_BASE,
1013         .name           = "evdev",
1014         .id_table       = evdev_ids,
1015 };
1016
1017 static int __init evdev_init(void)
1018 {
1019         return input_register_handler(&evdev_handler);
1020 }
1021
1022 static void __exit evdev_exit(void)
1023 {
1024         input_unregister_handler(&evdev_handler);
1025 }
1026
1027 module_init(evdev_init);
1028 module_exit(evdev_exit);
1029
1030 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1031 MODULE_DESCRIPTION("Input driver event char devices");
1032 MODULE_LICENSE("GPL");