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/mt.h>
  24 #include <linux/major.h>
  25 #include <linux/device.h>
  26 #include <linux/cdev.h>
  27 #include "input-compat.h"
  28
  29 struct evdev {
  30         int open;
  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         struct cdev cdev;
  39         bool exist;
  40 };
  41
  42 struct evdev_client {
  43         unsigned int head;
  44         unsigned int tail;
  45         unsigned int packet_head; /* [future] position of the first element of next packet */
  46         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  47         struct fasync_struct *fasync;
  48         struct evdev *evdev;
  49         struct list_head node;
  50         int clkid;
  51         unsigned int bufsize;
  52         struct input_event buffer[];
  53 };
  54
  55 /* flush queued events of type @type, caller must hold client->buffer_lock */
  56 static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
  57 {
  58         unsigned int i, head, num;
  59         unsigned int mask = client->bufsize - 1;
  60         bool is_report;
  61         struct input_event *ev;
  62
  63         BUG_ON(type == EV_SYN);
  64
  65         head = client->tail;
  66         client->packet_head = client->tail;
  67
  68         /* init to 1 so a leading SYN_REPORT will not be dropped */
  69         num = 1;
  70
  71         for (i = client->tail; i != client->head; i = (i + 1) & mask) {
  72                 ev = &client->buffer[i];
  73                 is_report = ev->type == EV_SYN && ev->code == SYN_REPORT;
  74
  75                 if (ev->type == type) {
  76                         /* drop matched entry */
  77                         continue;
  78                 } else if (is_report && !num) {
  79                         /* drop empty SYN_REPORT groups */
  80                         continue;
  81                 } else if (head != i) {
  82                         /* move entry to fill the gap */
  83                         client->buffer[head].time = ev->time;
  84                         client->buffer[head].type = ev->type;
  85                         client->buffer[head].code = ev->code;
  86                         client->buffer[head].value = ev->value;
  87                 }
  88
  89                 num++;
  90                 head = (head + 1) & mask;
  91
  92                 if (is_report) {
  93                         num = 0;
  94                         client->packet_head = head;
  95                 }
  96         }
  97
  98         client->head = head;
  99 }
 100
 101 /* queue SYN_DROPPED event */
 102 static void evdev_queue_syn_dropped(struct evdev_client *client)
 103 {
 104         unsigned long flags;
 105         struct input_event ev;
 106         ktime_t time;
 107
 108         time = ktime_get();
 109         if (client->clkid != CLOCK_MONOTONIC)
 110                 time = ktime_sub(time, ktime_get_monotonic_offset());
 111
 112         ev.time = ktime_to_timeval(time);
 113         ev.type = EV_SYN;
 114         ev.code = SYN_DROPPED;
 115         ev.value = 0;
 116
 117         spin_lock_irqsave(&client->buffer_lock, flags);
 118
 119         client->buffer[client->head++] = ev;
 120         client->head &= client->bufsize - 1;
 121
 122         if (unlikely(client->head == client->tail)) {
 123                 /* drop queue but keep our SYN_DROPPED event */
 124                 client->tail = (client->head - 1) & (client->bufsize - 1);
 125                 client->packet_head = client->tail;
 126         }
 127
 128         spin_unlock_irqrestore(&client->buffer_lock, flags);
 129 }
 130
 131 static void __pass_event(struct evdev_client *client,
 132                          const struct input_event *event)
 133 {
 134         client->buffer[client->head++] = *event;
 135         client->head &= client->bufsize - 1;
 136
 137         if (unlikely(client->head == client->tail)) {
 138                 /*
 139                  * This effectively "drops" all unconsumed events, leaving
 140                  * EV_SYN/SYN_DROPPED plus the newest event in the queue.
 141                  */
 142                 client->tail = (client->head - 2) & (client->bufsize - 1);
 143
 144                 client->buffer[client->tail].time = event->time;
 145                 client->buffer[client->tail].type = EV_SYN;
 146                 client->buffer[client->tail].code = SYN_DROPPED;
 147                 client->buffer[client->tail].value = 0;
 148
 149                 client->packet_head = client->tail;
 150         }
 151
 152         if (event->type == EV_SYN && event->code == SYN_REPORT) {
 153                 client->packet_head = client->head;
 154                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
 155         }
 156 }
 157
 158 static void evdev_pass_values(struct evdev_client *client,
 159                         const struct input_value *vals, unsigned int count,
 160                         ktime_t mono, ktime_t real)
 161 {
 162         struct evdev *evdev = client->evdev;
 163         const struct input_value *v;
 164         struct input_event event;
 165         bool wakeup = false;
 166
 167         event.time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ?
 168                                       mono : real);
 169
 170         /* Interrupts are disabled, just acquire the lock. */
 171         spin_lock(&client->buffer_lock);
 172
 173         for (v = vals; v != vals + count; v++) {
 174                 event.type = v->type;
 175                 event.code = v->code;
 176                 event.value = v->value;
 177                 __pass_event(client, &event);
 178                 if (v->type == EV_SYN && v->code == SYN_REPORT)
 179                         wakeup = true;
 180         }
 181
 182         spin_unlock(&client->buffer_lock);
 183
 184         if (wakeup)
 185                 wake_up_interruptible(&evdev->wait);
 186 }
 187
 188 /*
 189  * Pass incoming events to all connected clients.
 190  */
 191 static void evdev_events(struct input_handle *handle,
 192                          const struct input_value *vals, unsigned int count)
 193 {
 194         struct evdev *evdev = handle->private;
 195         struct evdev_client *client;
 196         ktime_t time_mono, time_real;
 197
 198         time_mono = ktime_get();
 199         time_real = ktime_sub(time_mono, ktime_get_monotonic_offset());
 200
 201         rcu_read_lock();
 202
 203         client = rcu_dereference(evdev->grab);
 204
 205         if (client)
 206                 evdev_pass_values(client, vals, count, time_mono, time_real);
 207         else
 208                 list_for_each_entry_rcu(client, &evdev->client_list, node)
 209                         evdev_pass_values(client, vals, count,
 210                                           time_mono, time_real);
 211
 212         rcu_read_unlock();
 213 }
 214
 215 /*
 216  * Pass incoming event to all connected clients.
 217  */
 218 static void evdev_event(struct input_handle *handle,
 219                         unsigned int type, unsigned int code, int value)
 220 {
 221         struct input_value vals[] = { { type, code, value } };
 222
 223         evdev_events(handle, vals, 1);
 224 }
 225
 226 static int evdev_fasync(int fd, struct file *file, int on)
 227 {
 228         struct evdev_client *client = file->private_data;
 229
 230         return fasync_helper(fd, file, on, &client->fasync);
 231 }
 232
 233 static int evdev_flush(struct file *file, fl_owner_t id)
 234 {
 235         struct evdev_client *client = file->private_data;
 236         struct evdev *evdev = client->evdev;
 237         int retval;
 238
 239         retval = mutex_lock_interruptible(&evdev->mutex);
 240         if (retval)
 241                 return retval;
 242
 243         if (!evdev->exist)
 244                 retval = -ENODEV;
 245         else
 246                 retval = input_flush_device(&evdev->handle, file);
 247
 248         mutex_unlock(&evdev->mutex);
 249         return retval;
 250 }
 251
 252 static void evdev_free(struct device *dev)
 253 {
 254         struct evdev *evdev = container_of(dev, struct evdev, dev);
 255
 256         input_put_device(evdev->handle.dev);
 257         kfree(evdev);
 258 }
 259
 260 /*
 261  * Grabs an event device (along with underlying input device).
 262  * This function is called with evdev->mutex taken.
 263  */
 264 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 265 {
 266         int error;
 267
 268         if (evdev->grab)
 269                 return -EBUSY;
 270
 271         error = input_grab_device(&evdev->handle);
 272         if (error)
 273                 return error;
 274
 275         rcu_assign_pointer(evdev->grab, client);
 276
 277         return 0;
 278 }
 279
 280 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 281 {
 282         struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
 283                                         lockdep_is_held(&evdev->mutex));
 284
 285         if (grab != client)
 286                 return  -EINVAL;
 287
 288         rcu_assign_pointer(evdev->grab, NULL);
 289         synchronize_rcu();
 290         input_release_device(&evdev->handle);
 291
 292         return 0;
 293 }
 294
 295 static void evdev_attach_client(struct evdev *evdev,
 296                                 struct evdev_client *client)
 297 {
 298         spin_lock(&evdev->client_lock);
 299         list_add_tail_rcu(&client->node, &evdev->client_list);
 300         spin_unlock(&evdev->client_lock);
 301 }
 302
 303 static void evdev_detach_client(struct evdev *evdev,
 304                                 struct evdev_client *client)
 305 {
 306         spin_lock(&evdev->client_lock);
 307         list_del_rcu(&client->node);
 308         spin_unlock(&evdev->client_lock);
 309         synchronize_rcu();
 310 }
 311
 312 static int evdev_open_device(struct evdev *evdev)
 313 {
 314         int retval;
 315
 316         retval = mutex_lock_interruptible(&evdev->mutex);
 317         if (retval)
 318                 return retval;
 319
 320         if (!evdev->exist)
 321                 retval = -ENODEV;
 322         else if (!evdev->open++) {
 323                 retval = input_open_device(&evdev->handle);
 324                 if (retval)
 325                         evdev->open--;
 326         }
 327
 328         mutex_unlock(&evdev->mutex);
 329         return retval;
 330 }
 331
 332 static void evdev_close_device(struct evdev *evdev)
 333 {
 334         mutex_lock(&evdev->mutex);
 335
 336         if (evdev->exist && !--evdev->open)
 337                 input_close_device(&evdev->handle);
 338
 339         mutex_unlock(&evdev->mutex);
 340 }
 341
 342 /*
 343  * Wake up users waiting for IO so they can disconnect from
 344  * dead device.
 345  */
 346 static void evdev_hangup(struct evdev *evdev)
 347 {
 348         struct evdev_client *client;
 349
 350         spin_lock(&evdev->client_lock);
 351         list_for_each_entry(client, &evdev->client_list, node)
 352                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 353         spin_unlock(&evdev->client_lock);
 354
 355         wake_up_interruptible(&evdev->wait);
 356 }
 357
 358 static int evdev_release(struct inode *inode, struct file *file)
 359 {
 360         struct evdev_client *client = file->private_data;
 361         struct evdev *evdev = client->evdev;
 362
 363         mutex_lock(&evdev->mutex);
 364         evdev_ungrab(evdev, client);
 365         mutex_unlock(&evdev->mutex);
 366
 367         evdev_detach_client(evdev, client);
 368         kfree(client);
 369
 370         evdev_close_device(evdev);
 371
 372         return 0;
 373 }
 374
 375 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 376 {
 377         unsigned int n_events =
 378                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 379                     EVDEV_MIN_BUFFER_SIZE);
 380
 381         return roundup_pow_of_two(n_events);
 382 }
 383
 384 static int evdev_open(struct inode *inode, struct file *file)
 385 {
 386         struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
 387         unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 388         struct evdev_client *client;
 389         int error;
 390
 391         client = kzalloc(sizeof(struct evdev_client) +
 392                                 bufsize * sizeof(struct input_event),
 393                          GFP_KERNEL);
 394         if (!client)
 395                 return -ENOMEM;
 396
 397         client->bufsize = bufsize;
 398         spin_lock_init(&client->buffer_lock);
 399         client->evdev = evdev;
 400         evdev_attach_client(evdev, client);
 401
 402         error = evdev_open_device(evdev);
 403         if (error)
 404                 goto err_free_client;
 405
 406         file->private_data = client;
 407         nonseekable_open(inode, file);
 408
 409         return 0;
 410
 411  err_free_client:
 412         evdev_detach_client(evdev, client);
 413         kfree(client);
 414         return error;
 415 }
 416
 417 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 418                            size_t count, loff_t *ppos)
 419 {
 420         struct evdev_client *client = file->private_data;
 421         struct evdev *evdev = client->evdev;
 422         struct input_event event;
 423         int retval = 0;
 424
 425         if (count != 0 && count < input_event_size())
 426                 return -EINVAL;
 427
 428         retval = mutex_lock_interruptible(&evdev->mutex);
 429         if (retval)
 430                 return retval;
 431
 432         if (!evdev->exist) {
 433                 retval = -ENODEV;
 434                 goto out;
 435         }
 436
 437         while (retval + input_event_size() <= count) {
 438
 439                 if (input_event_from_user(buffer + retval, &event)) {
 440                         retval = -EFAULT;
 441                         goto out;
 442                 }
 443                 retval += input_event_size();
 444
 445                 input_inject_event(&evdev->handle,
 446                                    event.type, event.code, event.value);
 447         }
 448
 449  out:
 450         mutex_unlock(&evdev->mutex);
 451         return retval;
 452 }
 453
 454 static int evdev_fetch_next_event(struct evdev_client *client,
 455                                   struct input_event *event)
 456 {
 457         int have_event;
 458
 459         spin_lock_irq(&client->buffer_lock);
 460
 461         have_event = client->packet_head != client->tail;
 462         if (have_event) {
 463                 *event = client->buffer[client->tail++];
 464                 client->tail &= client->bufsize - 1;
 465         }
 466
 467         spin_unlock_irq(&client->buffer_lock);
 468
 469         return have_event;
 470 }
 471
 472 static ssize_t evdev_read(struct file *file, char __user *buffer,
 473                           size_t count, loff_t *ppos)
 474 {
 475         struct evdev_client *client = file->private_data;
 476         struct evdev *evdev = client->evdev;
 477         struct input_event event;
 478         size_t read = 0;
 479         int error;
 480
 481         if (count != 0 && count < input_event_size())
 482                 return -EINVAL;
 483
 484         for (;;) {
 485                 if (!evdev->exist)
 486                         return -ENODEV;
 487
 488                 if (client->packet_head == client->tail &&
 489                     (file->f_flags & O_NONBLOCK))
 490                         return -EAGAIN;
 491
 492                 /*
 493                  * count == 0 is special - no IO is done but we check
 494                  * for error conditions (see above).
 495                  */
 496                 if (count == 0)
 497                         break;
 498
 499                 while (read + input_event_size() <= count &&
 500                        evdev_fetch_next_event(client, &event)) {
 501
 502                         if (input_event_to_user(buffer + read, &event))
 503                                 return -EFAULT;
 504
 505                         read += input_event_size();
 506                 }
 507
 508                 if (read)
 509                         break;
 510
 511                 if (!(file->f_flags & O_NONBLOCK)) {
 512                         error = wait_event_interruptible(evdev->wait,
 513                                         client->packet_head != client->tail ||
 514                                         !evdev->exist);
 515                         if (error)
 516                                 return error;
 517                 }
 518         }
 519
 520         return read;
 521 }
 522
 523 /* No kernel lock - fine */
 524 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 525 {
 526         struct evdev_client *client = file->private_data;
 527         struct evdev *evdev = client->evdev;
 528         unsigned int mask;
 529
 530         poll_wait(file, &evdev->wait, wait);
 531
 532         mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
 533         if (client->packet_head != client->tail)
 534                 mask |= POLLIN | POLLRDNORM;
 535
 536         return mask;
 537 }
 538
 539 #ifdef CONFIG_COMPAT
 540
 541 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 542 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 543
 544 #ifdef __BIG_ENDIAN
 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, i;
 549
 550         if (compat) {
 551                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 552                 if (len > maxlen)
 553                         len = maxlen;
 554
 555                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 556                         if (copy_to_user((compat_long_t __user *) p + i,
 557                                          (compat_long_t *) bits +
 558                                                 i + 1 - ((i % 2) << 1),
 559                                          sizeof(compat_long_t)))
 560                                 return -EFAULT;
 561         } else {
 562                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 563                 if (len > maxlen)
 564                         len = maxlen;
 565
 566                 if (copy_to_user(p, bits, len))
 567                         return -EFAULT;
 568         }
 569
 570         return len;
 571 }
 572 #else
 573 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 574                         unsigned int maxlen, void __user *p, int compat)
 575 {
 576         int len = compat ?
 577                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 578                         BITS_TO_LONGS(maxbit) * sizeof(long);
 579
 580         if (len > maxlen)
 581                 len = maxlen;
 582
 583         return copy_to_user(p, bits, len) ? -EFAULT : len;
 584 }
 585 #endif /* __BIG_ENDIAN */
 586
 587 #else
 588
 589 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 590                         unsigned int maxlen, void __user *p, int compat)
 591 {
 592         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 593
 594         if (len > maxlen)
 595                 len = maxlen;
 596
 597         return copy_to_user(p, bits, len) ? -EFAULT : len;
 598 }
 599
 600 #endif /* CONFIG_COMPAT */
 601
 602 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 603 {
 604         int len;
 605
 606         if (!str)
 607                 return -ENOENT;
 608
 609         len = strlen(str) + 1;
 610         if (len > maxlen)
 611                 len = maxlen;
 612
 613         return copy_to_user(p, str, len) ? -EFAULT : len;
 614 }
 615
 616 #define OLD_KEY_MAX     0x1ff
 617 static int handle_eviocgbit(struct input_dev *dev,
 618                             unsigned int type, unsigned int size,
 619                             void __user *p, int compat_mode)
 620 {
 621         static unsigned long keymax_warn_time;
 622         unsigned long *bits;
 623         int len;
 624
 625         switch (type) {
 626
 627         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 628         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 629         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 630         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 631         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 632         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 633         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 634         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 635         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 636         default: return -EINVAL;
 637         }
 638
 639         /*
 640          * Work around bugs in userspace programs that like to do
 641          * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
 642          * should be in bytes, not in bits.
 643          */
 644         if (type == EV_KEY && size == OLD_KEY_MAX) {
 645                 len = OLD_KEY_MAX;
 646                 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
 647                         pr_warning("(EVIOCGBIT): Suspicious buffer size %u, "
 648                                    "limiting output to %zu bytes. See "
 649                                    "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
 650                                    OLD_KEY_MAX,
 651                                    BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
 652         }
 653
 654         return bits_to_user(bits, len, size, p, compat_mode);
 655 }
 656 #undef OLD_KEY_MAX
 657
 658 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
 659 {
 660         struct input_keymap_entry ke = {
 661                 .len    = sizeof(unsigned int),
 662                 .flags  = 0,
 663         };
 664         int __user *ip = (int __user *)p;
 665         int error;
 666
 667         /* legacy case */
 668         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 669                 return -EFAULT;
 670
 671         error = input_get_keycode(dev, &ke);
 672         if (error)
 673                 return error;
 674
 675         if (put_user(ke.keycode, ip + 1))
 676                 return -EFAULT;
 677
 678         return 0;
 679 }
 680
 681 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
 682 {
 683         struct input_keymap_entry ke;
 684         int error;
 685
 686         if (copy_from_user(&ke, p, sizeof(ke)))
 687                 return -EFAULT;
 688
 689         error = input_get_keycode(dev, &ke);
 690         if (error)
 691                 return error;
 692
 693         if (copy_to_user(p, &ke, sizeof(ke)))
 694                 return -EFAULT;
 695
 696         return 0;
 697 }
 698
 699 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
 700 {
 701         struct input_keymap_entry ke = {
 702                 .len    = sizeof(unsigned int),
 703                 .flags  = 0,
 704         };
 705         int __user *ip = (int __user *)p;
 706
 707         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 708                 return -EFAULT;
 709
 710         if (get_user(ke.keycode, ip + 1))
 711                 return -EFAULT;
 712
 713         return input_set_keycode(dev, &ke);
 714 }
 715
 716 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
 717 {
 718         struct input_keymap_entry ke;
 719
 720         if (copy_from_user(&ke, p, sizeof(ke)))
 721                 return -EFAULT;
 722
 723         if (ke.len > sizeof(ke.scancode))
 724                 return -EINVAL;
 725
 726         return input_set_keycode(dev, &ke);
 727 }
 728
 729 /*
 730  * If we transfer state to the user, we should flush all pending events
 731  * of the same type from the client's queue. Otherwise, they might end up
 732  * with duplicate events, which can screw up client's state tracking.
 733  * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
 734  * event so user-space will notice missing events.
 735  *
 736  * LOCKING:
 737  * We need to take event_lock before buffer_lock to avoid dead-locks. But we
 738  * need the even_lock only to guarantee consistent state. We can safely release
 739  * it while flushing the queue. This allows input-core to handle filters while
 740  * we flush the queue.
 741  */
 742 static int evdev_handle_get_val(struct evdev_client *client,
 743                                 struct input_dev *dev, unsigned int type,
 744                                 unsigned long *bits, unsigned int max,
 745                                 unsigned int size, void __user *p, int compat)
 746 {
 747         int ret;
 748         unsigned long *mem;
 749
 750         mem = kmalloc(sizeof(unsigned long) * max, GFP_KERNEL);
 751         if (!mem)
 752                 return -ENOMEM;
 753
 754         spin_lock_irq(&dev->event_lock);
 755         spin_lock(&client->buffer_lock);
 756
 757         memcpy(mem, bits, sizeof(unsigned long) * max);
 758
 759         spin_unlock(&dev->event_lock);
 760
 761         __evdev_flush_queue(client, type);
 762
 763         spin_unlock_irq(&client->buffer_lock);
 764
 765         ret = bits_to_user(mem, max, size, p, compat);
 766         if (ret < 0)
 767                 evdev_queue_syn_dropped(client);
 768
 769         kfree(mem);
 770
 771         return ret;
 772 }
 773
 774 static int evdev_handle_mt_request(struct input_dev *dev,
 775                                    unsigned int size,
 776                                    int __user *ip)
 777 {
 778         const struct input_mt *mt = dev->mt;
 779         unsigned int code;
 780         int max_slots;
 781         int i;
 782
 783         if (get_user(code, &ip[0]))
 784                 return -EFAULT;
 785         if (!mt || !input_is_mt_value(code))
 786                 return -EINVAL;
 787
 788         max_slots = (size - sizeof(__u32)) / sizeof(__s32);
 789         for (i = 0; i < mt->num_slots && i < max_slots; i++) {
 790                 int value = input_mt_get_value(&mt->slots[i], code);
 791                 if (put_user(value, &ip[1 + i]))
 792                         return -EFAULT;
 793         }
 794
 795         return 0;
 796 }
 797
 798 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 799                            void __user *p, int compat_mode)
 800 {
 801         struct evdev_client *client = file->private_data;
 802         struct evdev *evdev = client->evdev;
 803         struct input_dev *dev = evdev->handle.dev;
 804         struct input_absinfo abs;
 805         struct ff_effect effect;
 806         int __user *ip = (int __user *)p;
 807         unsigned int i, t, u, v;
 808         unsigned int size;
 809         int error;
 810
 811         /* First we check for fixed-length commands */
 812         switch (cmd) {
 813
 814         case EVIOCGVERSION:
 815                 return put_user(EV_VERSION, ip);
 816
 817         case EVIOCGID:
 818                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 819                         return -EFAULT;
 820                 return 0;
 821
 822         case EVIOCGREP:
 823                 if (!test_bit(EV_REP, dev->evbit))
 824                         return -ENOSYS;
 825                 if (put_user(dev->rep[REP_DELAY], ip))
 826                         return -EFAULT;
 827                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 828                         return -EFAULT;
 829                 return 0;
 830
 831         case EVIOCSREP:
 832                 if (!test_bit(EV_REP, dev->evbit))
 833                         return -ENOSYS;
 834                 if (get_user(u, ip))
 835                         return -EFAULT;
 836                 if (get_user(v, ip + 1))
 837                         return -EFAULT;
 838
 839                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 840                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 841
 842                 return 0;
 843
 844         case EVIOCRMFF:
 845                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 846
 847         case EVIOCGEFFECTS:
 848                 i = test_bit(EV_FF, dev->evbit) ?
 849                                 dev->ff->max_effects : 0;
 850                 if (put_user(i, ip))
 851                         return -EFAULT;
 852                 return 0;
 853
 854         case EVIOCGRAB:
 855                 if (p)
 856                         return evdev_grab(evdev, client);
 857                 else
 858                         return evdev_ungrab(evdev, client);
 859
 860         case EVIOCSCLOCKID:
 861                 if (copy_from_user(&i, p, sizeof(unsigned int)))
 862                         return -EFAULT;
 863                 if (i != CLOCK_MONOTONIC && i != CLOCK_REALTIME)
 864                         return -EINVAL;
 865                 client->clkid = i;
 866                 return 0;
 867
 868         case EVIOCGKEYCODE:
 869                 return evdev_handle_get_keycode(dev, p);
 870
 871         case EVIOCSKEYCODE:
 872                 return evdev_handle_set_keycode(dev, p);
 873
 874         case EVIOCGKEYCODE_V2:
 875                 return evdev_handle_get_keycode_v2(dev, p);
 876
 877         case EVIOCSKEYCODE_V2:
 878                 return evdev_handle_set_keycode_v2(dev, p);
 879         }
 880
 881         size = _IOC_SIZE(cmd);
 882
 883         /* Now check variable-length commands */
 884 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
 885         switch (EVIOC_MASK_SIZE(cmd)) {
 886
 887         case EVIOCGPROP(0):
 888                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
 889                                     size, p, compat_mode);
 890
 891         case EVIOCGMTSLOTS(0):
 892                 return evdev_handle_mt_request(dev, size, ip);
 893
 894         case EVIOCGKEY(0):
 895                 return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
 896                                             KEY_MAX, size, p, compat_mode);
 897
 898         case EVIOCGLED(0):
 899                 return evdev_handle_get_val(client, dev, EV_LED, dev->led,
 900                                             LED_MAX, size, p, compat_mode);
 901
 902         case EVIOCGSND(0):
 903                 return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
 904                                             SND_MAX, size, p, compat_mode);
 905
 906         case EVIOCGSW(0):
 907                 return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
 908                                             SW_MAX, size, p, compat_mode);
 909
 910         case EVIOCGNAME(0):
 911                 return str_to_user(dev->name, size, p);
 912
 913         case EVIOCGPHYS(0):
 914                 return str_to_user(dev->phys, size, p);
 915
 916         case EVIOCGUNIQ(0):
 917                 return str_to_user(dev->uniq, size, p);
 918
 919         case EVIOC_MASK_SIZE(EVIOCSFF):
 920                 if (input_ff_effect_from_user(p, size, &effect))
 921                         return -EFAULT;
 922
 923                 error = input_ff_upload(dev, &effect, file);
 924
 925                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 926                         return -EFAULT;
 927
 928                 return error;
 929         }
 930
 931         /* Multi-number variable-length handlers */
 932         if (_IOC_TYPE(cmd) != 'E')
 933                 return -EINVAL;
 934
 935         if (_IOC_DIR(cmd) == _IOC_READ) {
 936
 937                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
 938                         return handle_eviocgbit(dev,
 939                                                 _IOC_NR(cmd) & EV_MAX, size,
 940                                                 p, compat_mode);
 941
 942                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 943
 944                         if (!dev->absinfo)
 945                                 return -EINVAL;
 946
 947                         t = _IOC_NR(cmd) & ABS_MAX;
 948                         abs = dev->absinfo[t];
 949
 950                         if (copy_to_user(p, &abs, min_t(size_t,
 951                                         size, sizeof(struct input_absinfo))))
 952                                 return -EFAULT;
 953
 954                         return 0;
 955                 }
 956         }
 957
 958         if (_IOC_DIR(cmd) == _IOC_WRITE) {
 959
 960                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 961
 962                         if (!dev->absinfo)
 963                                 return -EINVAL;
 964
 965                         t = _IOC_NR(cmd) & ABS_MAX;
 966
 967                         if (copy_from_user(&abs, p, min_t(size_t,
 968                                         size, sizeof(struct input_absinfo))))
 969                                 return -EFAULT;
 970
 971                         if (size < sizeof(struct input_absinfo))
 972                                 abs.resolution = 0;
 973
 974                         /* We can't change number of reserved MT slots */
 975                         if (t == ABS_MT_SLOT)
 976                                 return -EINVAL;
 977
 978                         /*
 979                          * Take event lock to ensure that we are not
 980                          * changing device parameters in the middle
 981                          * of event.
 982                          */
 983                         spin_lock_irq(&dev->event_lock);
 984                         dev->absinfo[t] = abs;
 985                         spin_unlock_irq(&dev->event_lock);
 986
 987                         return 0;
 988                 }
 989         }
 990
 991         return -EINVAL;
 992 }
 993
 994 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 995                                 void __user *p, int compat_mode)
 996 {
 997         struct evdev_client *client = file->private_data;
 998         struct evdev *evdev = client->evdev;
 999         int retval;
1000
1001         retval = mutex_lock_interruptible(&evdev->mutex);
1002         if (retval)
1003                 return retval;
1004
1005         if (!evdev->exist) {
1006                 retval = -ENODEV;
1007                 goto out;
1008         }
1009
1010         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1011
1012  out:
1013         mutex_unlock(&evdev->mutex);
1014         return retval;
1015 }
1016
1017 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1018 {
1019         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1020 }
1021
1022 #ifdef CONFIG_COMPAT
1023 static long evdev_ioctl_compat(struct file *file,
1024                                 unsigned int cmd, unsigned long arg)
1025 {
1026         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1027 }
1028 #endif
1029
1030 static const struct file_operations evdev_fops = {
1031         .owner          = THIS_MODULE,
1032         .read           = evdev_read,
1033         .write          = evdev_write,
1034         .poll           = evdev_poll,
1035         .open           = evdev_open,
1036         .release        = evdev_release,
1037         .unlocked_ioctl = evdev_ioctl,
1038 #ifdef CONFIG_COMPAT
1039         .compat_ioctl   = evdev_ioctl_compat,
1040 #endif
1041         .fasync         = evdev_fasync,
1042         .flush          = evdev_flush,
1043         .llseek         = no_llseek,
1044 };
1045
1046 /*
1047  * Mark device non-existent. This disables writes, ioctls and
1048  * prevents new users from opening the device. Already posted
1049  * blocking reads will stay, however new ones will fail.
1050  */
1051 static void evdev_mark_dead(struct evdev *evdev)
1052 {
1053         mutex_lock(&evdev->mutex);
1054         evdev->exist = false;
1055         mutex_unlock(&evdev->mutex);
1056 }
1057
1058 static void evdev_cleanup(struct evdev *evdev)
1059 {
1060         struct input_handle *handle = &evdev->handle;
1061
1062         evdev_mark_dead(evdev);
1063         evdev_hangup(evdev);
1064
1065         cdev_del(&evdev->cdev);
1066
1067         /* evdev is marked dead so no one else accesses evdev->open */
1068         if (evdev->open) {
1069                 input_flush_device(handle, NULL);
1070                 input_close_device(handle);
1071         }
1072 }
1073
1074 /*
1075  * Create new evdev device. Note that input core serializes calls
1076  * to connect and disconnect.
1077  */
1078 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1079                          const struct input_device_id *id)
1080 {
1081         struct evdev *evdev;
1082         int minor;
1083         int dev_no;
1084         int error;
1085
1086         minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1087         if (minor < 0) {
1088                 error = minor;
1089                 pr_err("failed to reserve new minor: %d\n", error);
1090                 return error;
1091         }
1092
1093         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1094         if (!evdev) {
1095                 error = -ENOMEM;
1096                 goto err_free_minor;
1097         }
1098
1099         INIT_LIST_HEAD(&evdev->client_list);
1100         spin_lock_init(&evdev->client_lock);
1101         mutex_init(&evdev->mutex);
1102         init_waitqueue_head(&evdev->wait);
1103         evdev->exist = true;
1104
1105         dev_no = minor;
1106         /* Normalize device number if it falls into legacy range */
1107         if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1108                 dev_no -= EVDEV_MINOR_BASE;
1109         dev_set_name(&evdev->dev, "event%d", dev_no);
1110
1111         evdev->handle.dev = input_get_device(dev);
1112         evdev->handle.name = dev_name(&evdev->dev);
1113         evdev->handle.handler = handler;
1114         evdev->handle.private = evdev;
1115
1116         evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1117         evdev->dev.class = &input_class;
1118         evdev->dev.parent = &dev->dev;
1119         evdev->dev.release = evdev_free;
1120         device_initialize(&evdev->dev);
1121
1122         error = input_register_handle(&evdev->handle);
1123         if (error)
1124                 goto err_free_evdev;
1125
1126         cdev_init(&evdev->cdev, &evdev_fops);
1127         evdev->cdev.kobj.parent = &evdev->dev.kobj;
1128         error = cdev_add(&evdev->cdev, evdev->dev.devt, 1);
1129         if (error)
1130                 goto err_unregister_handle;
1131
1132         error = device_add(&evdev->dev);
1133         if (error)
1134                 goto err_cleanup_evdev;
1135
1136         return 0;
1137
1138  err_cleanup_evdev:
1139         evdev_cleanup(evdev);
1140  err_unregister_handle:
1141         input_unregister_handle(&evdev->handle);
1142  err_free_evdev:
1143         put_device(&evdev->dev);
1144  err_free_minor:
1145         input_free_minor(minor);
1146         return error;
1147 }
1148
1149 static void evdev_disconnect(struct input_handle *handle)
1150 {
1151         struct evdev *evdev = handle->private;
1152
1153         device_del(&evdev->dev);
1154         evdev_cleanup(evdev);
1155         input_free_minor(MINOR(evdev->dev.devt));
1156         input_unregister_handle(handle);
1157         put_device(&evdev->dev);
1158 }
1159
1160 static const struct input_device_id evdev_ids[] = {
1161         { .driver_info = 1 },   /* Matches all devices */
1162         { },                    /* Terminating zero entry */
1163 };
1164
1165 MODULE_DEVICE_TABLE(input, evdev_ids);
1166
1167 static struct input_handler evdev_handler = {
1168         .event          = evdev_event,
1169         .events         = evdev_events,
1170         .connect        = evdev_connect,
1171         .disconnect     = evdev_disconnect,
1172         .legacy_minors  = true,
1173         .minor          = EVDEV_MINOR_BASE,
1174         .name           = "evdev",
1175         .id_table       = evdev_ids,
1176 };
1177
1178 static int __init evdev_init(void)
1179 {
1180         return input_register_handler(&evdev_handler);
1181 }
1182
1183 static void __exit evdev_exit(void)
1184 {
1185         input_unregister_handler(&evdev_handler);
1186 }
1187
1188 module_init(evdev_init);
1189 module_exit(evdev_exit);
1190
1191 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1192 MODULE_DESCRIPTION("Input driver event char devices");
1193 MODULE_LICENSE("GPL");