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/vmalloc.h>
  22 #include <linux/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25 #include <linux/input/mt.h>
  26 #include <linux/major.h>
  27 #include <linux/device.h>
  28 #include <linux/cdev.h>
  29 #include "input-compat.h"
  30
  31 enum evdev_clock_type {
  32         EV_CLK_REAL = 0,
  33         EV_CLK_MONO,
  34         EV_CLK_BOOT,
  35         EV_CLK_MAX
  36 };
  37
  38 struct evdev {
  39         int open;
  40         struct input_handle handle;
  41         wait_queue_head_t wait;
  42         struct evdev_client __rcu *grab;
  43         struct list_head client_list;
  44         spinlock_t client_lock; /* protects client_list */
  45         struct mutex mutex;
  46         struct device dev;
  47         struct cdev cdev;
  48         bool exist;
  49 };
  50
  51 struct evdev_client {
  52         unsigned int head;
  53         unsigned int tail;
  54         unsigned int packet_head; /* [future] position of the first element of next packet */
  55         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  56         struct fasync_struct *fasync;
  57         struct evdev *evdev;
  58         struct list_head node;
  59         int clk_type;
  60         bool revoked;
  61         unsigned int bufsize;
  62         struct input_event buffer[];
  63 };
  64
  65 /* flush queued events of type @type, caller must hold client->buffer_lock */
  66 static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
  67 {
  68         unsigned int i, head, num;
  69         unsigned int mask = client->bufsize - 1;
  70         bool is_report;
  71         struct input_event *ev;
  72
  73         BUG_ON(type == EV_SYN);
  74
  75         head = client->tail;
  76         client->packet_head = client->tail;
  77
  78         /* init to 1 so a leading SYN_REPORT will not be dropped */
  79         num = 1;
  80
  81         for (i = client->tail; i != client->head; i = (i + 1) & mask) {
  82                 ev = &client->buffer[i];
  83                 is_report = ev->type == EV_SYN && ev->code == SYN_REPORT;
  84
  85                 if (ev->type == type) {
  86                         /* drop matched entry */
  87                         continue;
  88                 } else if (is_report && !num) {
  89                         /* drop empty SYN_REPORT groups */
  90                         continue;
  91                 } else if (head != i) {
  92                         /* move entry to fill the gap */
  93                         client->buffer[head].time = ev->time;
  94                         client->buffer[head].type = ev->type;
  95                         client->buffer[head].code = ev->code;
  96                         client->buffer[head].value = ev->value;
  97                 }
  98
  99                 num++;
 100                 head = (head + 1) & mask;
 101
 102                 if (is_report) {
 103                         num = 0;
 104                         client->packet_head = head;
 105                 }
 106         }
 107
 108         client->head = head;
 109 }
 110
 111 /* queue SYN_DROPPED event and flush queue if flush parameter is true */
 112 static void evdev_queue_syn_dropped(struct evdev_client *client, bool flush)
 113 {
 114         unsigned long flags;
 115         struct input_event ev;
 116         ktime_t time;
 117
 118         time = client->clk_type == EV_CLK_REAL ?
 119                         ktime_get_real() :
 120                         client->clk_type == EV_CLK_MONO ?
 121                                 ktime_get() :
 122                                 ktime_get_boottime();
 123
 124         ev.time = ktime_to_timeval(time);
 125         ev.type = EV_SYN;
 126         ev.code = SYN_DROPPED;
 127         ev.value = 0;
 128
 129         spin_lock_irqsave(&client->buffer_lock, flags);
 130
 131         if (flush)
 132                 client->packet_head = client->head = client->tail;
 133
 134         client->buffer[client->head++] = ev;
 135         client->head &= client->bufsize - 1;
 136
 137         if (unlikely(client->head == client->tail)) {
 138                 /* drop queue but keep our SYN_DROPPED event */
 139                 client->tail = (client->head - 1) & (client->bufsize - 1);
 140                 client->packet_head = client->tail;
 141         }
 142
 143         spin_unlock_irqrestore(&client->buffer_lock, flags);
 144 }
 145
 146 static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid)
 147 {
 148         if (client->clk_type == clkid)
 149                 return 0;
 150
 151         switch (clkid) {
 152
 153         case CLOCK_REALTIME:
 154                 client->clk_type = EV_CLK_REAL;
 155                 break;
 156         case CLOCK_MONOTONIC:
 157                 client->clk_type = EV_CLK_MONO;
 158                 break;
 159         case CLOCK_BOOTTIME:
 160                 client->clk_type = EV_CLK_BOOT;
 161                 break;
 162         default:
 163                 return -EINVAL;
 164         }
 165
 166         /* Flush pending events and queue SYN_DROPPED event.*/
 167         evdev_queue_syn_dropped(client, true);
 168
 169         return 0;
 170 }
 171
 172 static void __pass_event(struct evdev_client *client,
 173                          const struct input_event *event)
 174 {
 175         client->buffer[client->head++] = *event;
 176         client->head &= client->bufsize - 1;
 177
 178         if (unlikely(client->head == client->tail)) {
 179                 /*
 180                  * This effectively "drops" all unconsumed events, leaving
 181                  * EV_SYN/SYN_DROPPED plus the newest event in the queue.
 182                  */
 183                 client->tail = (client->head - 2) & (client->bufsize - 1);
 184
 185                 client->buffer[client->tail].time = event->time;
 186                 client->buffer[client->tail].type = EV_SYN;
 187                 client->buffer[client->tail].code = SYN_DROPPED;
 188                 client->buffer[client->tail].value = 0;
 189
 190                 client->packet_head = client->tail;
 191         }
 192
 193         if (event->type == EV_SYN && event->code == SYN_REPORT) {
 194                 client->packet_head = client->head;
 195                 kill_fasync(&client->fasync, SIGIO, POLL_IN);
 196         }
 197 }
 198
 199 static void evdev_pass_values(struct evdev_client *client,
 200                         const struct input_value *vals, unsigned int count,
 201                         ktime_t *ev_time)
 202 {
 203         struct evdev *evdev = client->evdev;
 204         const struct input_value *v;
 205         struct input_event event;
 206         bool wakeup = false;
 207
 208         if (client->revoked)
 209                 return;
 210
 211         event.time = ktime_to_timeval(ev_time[client->clk_type]);
 212
 213         /* Interrupts are disabled, just acquire the lock. */
 214         spin_lock(&client->buffer_lock);
 215
 216         for (v = vals; v != vals + count; v++) {
 217                 event.type = v->type;
 218                 event.code = v->code;
 219                 event.value = v->value;
 220                 __pass_event(client, &event);
 221                 if (v->type == EV_SYN && v->code == SYN_REPORT)
 222                         wakeup = true;
 223         }
 224
 225         spin_unlock(&client->buffer_lock);
 226
 227         if (wakeup)
 228                 wake_up_interruptible(&evdev->wait);
 229 }
 230
 231 /*
 232  * Pass incoming events to all connected clients.
 233  */
 234 static void evdev_events(struct input_handle *handle,
 235                          const struct input_value *vals, unsigned int count)
 236 {
 237         struct evdev *evdev = handle->private;
 238         struct evdev_client *client;
 239         ktime_t ev_time[EV_CLK_MAX];
 240
 241         ev_time[EV_CLK_MONO] = ktime_get();
 242         ev_time[EV_CLK_REAL] = ktime_mono_to_real(ev_time[EV_CLK_MONO]);
 243         ev_time[EV_CLK_BOOT] = ktime_mono_to_any(ev_time[EV_CLK_MONO],
 244                                                  TK_OFFS_BOOT);
 245
 246         rcu_read_lock();
 247
 248         client = rcu_dereference(evdev->grab);
 249
 250         if (client)
 251                 evdev_pass_values(client, vals, count, ev_time);
 252         else
 253                 list_for_each_entry_rcu(client, &evdev->client_list, node)
 254                         evdev_pass_values(client, vals, count, ev_time);
 255
 256         rcu_read_unlock();
 257 }
 258
 259 /*
 260  * Pass incoming event to all connected clients.
 261  */
 262 static void evdev_event(struct input_handle *handle,
 263                         unsigned int type, unsigned int code, int value)
 264 {
 265         struct input_value vals[] = { { type, code, value } };
 266
 267         evdev_events(handle, vals, 1);
 268 }
 269
 270 static int evdev_fasync(int fd, struct file *file, int on)
 271 {
 272         struct evdev_client *client = file->private_data;
 273
 274         return fasync_helper(fd, file, on, &client->fasync);
 275 }
 276
 277 static int evdev_flush(struct file *file, fl_owner_t id)
 278 {
 279         struct evdev_client *client = file->private_data;
 280         struct evdev *evdev = client->evdev;
 281         int retval;
 282
 283         retval = mutex_lock_interruptible(&evdev->mutex);
 284         if (retval)
 285                 return retval;
 286
 287         if (!evdev->exist || client->revoked)
 288                 retval = -ENODEV;
 289         else
 290                 retval = input_flush_device(&evdev->handle, file);
 291
 292         mutex_unlock(&evdev->mutex);
 293         return retval;
 294 }
 295
 296 static void evdev_free(struct device *dev)
 297 {
 298         struct evdev *evdev = container_of(dev, struct evdev, dev);
 299
 300         input_put_device(evdev->handle.dev);
 301         kfree(evdev);
 302 }
 303
 304 /*
 305  * Grabs an event device (along with underlying input device).
 306  * This function is called with evdev->mutex taken.
 307  */
 308 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 309 {
 310         int error;
 311
 312         if (evdev->grab)
 313                 return -EBUSY;
 314
 315         error = input_grab_device(&evdev->handle);
 316         if (error)
 317                 return error;
 318
 319         rcu_assign_pointer(evdev->grab, client);
 320
 321         return 0;
 322 }
 323
 324 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 325 {
 326         struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
 327                                         lockdep_is_held(&evdev->mutex));
 328
 329         if (grab != client)
 330                 return  -EINVAL;
 331
 332         rcu_assign_pointer(evdev->grab, NULL);
 333         synchronize_rcu();
 334         input_release_device(&evdev->handle);
 335
 336         return 0;
 337 }
 338
 339 static void evdev_attach_client(struct evdev *evdev,
 340                                 struct evdev_client *client)
 341 {
 342         spin_lock(&evdev->client_lock);
 343         list_add_tail_rcu(&client->node, &evdev->client_list);
 344         spin_unlock(&evdev->client_lock);
 345 }
 346
 347 static void evdev_detach_client(struct evdev *evdev,
 348                                 struct evdev_client *client)
 349 {
 350         spin_lock(&evdev->client_lock);
 351         list_del_rcu(&client->node);
 352         spin_unlock(&evdev->client_lock);
 353         synchronize_rcu();
 354 }
 355
 356 static int evdev_open_device(struct evdev *evdev)
 357 {
 358         int retval;
 359
 360         retval = mutex_lock_interruptible(&evdev->mutex);
 361         if (retval)
 362                 return retval;
 363
 364         if (!evdev->exist)
 365                 retval = -ENODEV;
 366         else if (!evdev->open++) {
 367                 retval = input_open_device(&evdev->handle);
 368                 if (retval)
 369                         evdev->open--;
 370         }
 371
 372         mutex_unlock(&evdev->mutex);
 373         return retval;
 374 }
 375
 376 static void evdev_close_device(struct evdev *evdev)
 377 {
 378         mutex_lock(&evdev->mutex);
 379
 380         if (evdev->exist && !--evdev->open)
 381                 input_close_device(&evdev->handle);
 382
 383         mutex_unlock(&evdev->mutex);
 384 }
 385
 386 /*
 387  * Wake up users waiting for IO so they can disconnect from
 388  * dead device.
 389  */
 390 static void evdev_hangup(struct evdev *evdev)
 391 {
 392         struct evdev_client *client;
 393
 394         spin_lock(&evdev->client_lock);
 395         list_for_each_entry(client, &evdev->client_list, node)
 396                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 397         spin_unlock(&evdev->client_lock);
 398
 399         wake_up_interruptible(&evdev->wait);
 400 }
 401
 402 static int evdev_release(struct inode *inode, struct file *file)
 403 {
 404         struct evdev_client *client = file->private_data;
 405         struct evdev *evdev = client->evdev;
 406
 407         mutex_lock(&evdev->mutex);
 408         evdev_ungrab(evdev, client);
 409         mutex_unlock(&evdev->mutex);
 410
 411         evdev_detach_client(evdev, client);
 412
 413         if (is_vmalloc_addr(client))
 414                 vfree(client);
 415         else
 416                 kfree(client);
 417
 418         evdev_close_device(evdev);
 419
 420         return 0;
 421 }
 422
 423 static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 424 {
 425         unsigned int n_events =
 426                 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 427                     EVDEV_MIN_BUFFER_SIZE);
 428
 429         return roundup_pow_of_two(n_events);
 430 }
 431
 432 static int evdev_open(struct inode *inode, struct file *file)
 433 {
 434         struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
 435         unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 436         unsigned int size = sizeof(struct evdev_client) +
 437                                         bufsize * sizeof(struct input_event);
 438         struct evdev_client *client;
 439         int error;
 440
 441         client = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
 442         if (!client)
 443                 client = vzalloc(size);
 444         if (!client)
 445                 return -ENOMEM;
 446
 447         client->bufsize = bufsize;
 448         spin_lock_init(&client->buffer_lock);
 449         client->evdev = evdev;
 450         evdev_attach_client(evdev, client);
 451
 452         error = evdev_open_device(evdev);
 453         if (error)
 454                 goto err_free_client;
 455
 456         file->private_data = client;
 457         nonseekable_open(inode, file);
 458
 459         return 0;
 460
 461  err_free_client:
 462         evdev_detach_client(evdev, client);
 463         kvfree(client);
 464         return error;
 465 }
 466
 467 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 468                            size_t count, loff_t *ppos)
 469 {
 470         struct evdev_client *client = file->private_data;
 471         struct evdev *evdev = client->evdev;
 472         struct input_event event;
 473         int retval = 0;
 474
 475         if (count != 0 && count < input_event_size())
 476                 return -EINVAL;
 477
 478         retval = mutex_lock_interruptible(&evdev->mutex);
 479         if (retval)
 480                 return retval;
 481
 482         if (!evdev->exist || client->revoked) {
 483                 retval = -ENODEV;
 484                 goto out;
 485         }
 486
 487         while (retval + input_event_size() <= count) {
 488
 489                 if (input_event_from_user(buffer + retval, &event)) {
 490                         retval = -EFAULT;
 491                         goto out;
 492                 }
 493                 retval += input_event_size();
 494
 495                 input_inject_event(&evdev->handle,
 496                                    event.type, event.code, event.value);
 497         }
 498
 499  out:
 500         mutex_unlock(&evdev->mutex);
 501         return retval;
 502 }
 503
 504 static int evdev_fetch_next_event(struct evdev_client *client,
 505                                   struct input_event *event)
 506 {
 507         int have_event;
 508
 509         spin_lock_irq(&client->buffer_lock);
 510
 511         have_event = client->packet_head != client->tail;
 512         if (have_event) {
 513                 *event = client->buffer[client->tail++];
 514                 client->tail &= client->bufsize - 1;
 515         }
 516
 517         spin_unlock_irq(&client->buffer_lock);
 518
 519         return have_event;
 520 }
 521
 522 static ssize_t evdev_read(struct file *file, char __user *buffer,
 523                           size_t count, loff_t *ppos)
 524 {
 525         struct evdev_client *client = file->private_data;
 526         struct evdev *evdev = client->evdev;
 527         struct input_event event;
 528         size_t read = 0;
 529         int error;
 530
 531         if (count != 0 && count < input_event_size())
 532                 return -EINVAL;
 533
 534         for (;;) {
 535                 if (!evdev->exist || client->revoked)
 536                         return -ENODEV;
 537
 538                 if (client->packet_head == client->tail &&
 539                     (file->f_flags & O_NONBLOCK))
 540                         return -EAGAIN;
 541
 542                 /*
 543                  * count == 0 is special - no IO is done but we check
 544                  * for error conditions (see above).
 545                  */
 546                 if (count == 0)
 547                         break;
 548
 549                 while (read + input_event_size() <= count &&
 550                        evdev_fetch_next_event(client, &event)) {
 551
 552                         if (input_event_to_user(buffer + read, &event))
 553                                 return -EFAULT;
 554
 555                         read += input_event_size();
 556                 }
 557
 558                 if (read)
 559                         break;
 560
 561                 if (!(file->f_flags & O_NONBLOCK)) {
 562                         error = wait_event_interruptible(evdev->wait,
 563                                         client->packet_head != client->tail ||
 564                                         !evdev->exist || client->revoked);
 565                         if (error)
 566                                 return error;
 567                 }
 568         }
 569
 570         return read;
 571 }
 572
 573 /* No kernel lock - fine */
 574 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 575 {
 576         struct evdev_client *client = file->private_data;
 577         struct evdev *evdev = client->evdev;
 578         unsigned int mask;
 579
 580         poll_wait(file, &evdev->wait, wait);
 581
 582         if (evdev->exist && !client->revoked)
 583                 mask = POLLOUT | POLLWRNORM;
 584         else
 585                 mask = POLLHUP | POLLERR;
 586
 587         if (client->packet_head != client->tail)
 588                 mask |= POLLIN | POLLRDNORM;
 589
 590         return mask;
 591 }
 592
 593 #ifdef CONFIG_COMPAT
 594
 595 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 596 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 597
 598 #ifdef __BIG_ENDIAN
 599 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 600                         unsigned int maxlen, void __user *p, int compat)
 601 {
 602         int len, i;
 603
 604         if (compat) {
 605                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 606                 if (len > maxlen)
 607                         len = maxlen;
 608
 609                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 610                         if (copy_to_user((compat_long_t __user *) p + i,
 611                                          (compat_long_t *) bits +
 612                                                 i + 1 - ((i % 2) << 1),
 613                                          sizeof(compat_long_t)))
 614                                 return -EFAULT;
 615         } else {
 616                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 617                 if (len > maxlen)
 618                         len = maxlen;
 619
 620                 if (copy_to_user(p, bits, len))
 621                         return -EFAULT;
 622         }
 623
 624         return len;
 625 }
 626 #else
 627 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 628                         unsigned int maxlen, void __user *p, int compat)
 629 {
 630         int len = compat ?
 631                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 632                         BITS_TO_LONGS(maxbit) * sizeof(long);
 633
 634         if (len > maxlen)
 635                 len = maxlen;
 636
 637         return copy_to_user(p, bits, len) ? -EFAULT : len;
 638 }
 639 #endif /* __BIG_ENDIAN */
 640
 641 #else
 642
 643 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 644                         unsigned int maxlen, void __user *p, int compat)
 645 {
 646         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 647
 648         if (len > maxlen)
 649                 len = maxlen;
 650
 651         return copy_to_user(p, bits, len) ? -EFAULT : len;
 652 }
 653
 654 #endif /* CONFIG_COMPAT */
 655
 656 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 657 {
 658         int len;
 659
 660         if (!str)
 661                 return -ENOENT;
 662
 663         len = strlen(str) + 1;
 664         if (len > maxlen)
 665                 len = maxlen;
 666
 667         return copy_to_user(p, str, len) ? -EFAULT : len;
 668 }
 669
 670 static int handle_eviocgbit(struct input_dev *dev,
 671                             unsigned int type, unsigned int size,
 672                             void __user *p, int compat_mode)
 673 {
 674         unsigned long *bits;
 675         int len;
 676
 677         switch (type) {
 678
 679         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 680         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 681         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 682         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 683         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 684         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 685         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 686         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 687         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 688         default: return -EINVAL;
 689         }
 690
 691         return bits_to_user(bits, len, size, p, compat_mode);
 692 }
 693
 694 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
 695 {
 696         struct input_keymap_entry ke = {
 697                 .len    = sizeof(unsigned int),
 698                 .flags  = 0,
 699         };
 700         int __user *ip = (int __user *)p;
 701         int error;
 702
 703         /* legacy case */
 704         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 705                 return -EFAULT;
 706
 707         error = input_get_keycode(dev, &ke);
 708         if (error)
 709                 return error;
 710
 711         if (put_user(ke.keycode, ip + 1))
 712                 return -EFAULT;
 713
 714         return 0;
 715 }
 716
 717 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
 718 {
 719         struct input_keymap_entry ke;
 720         int error;
 721
 722         if (copy_from_user(&ke, p, sizeof(ke)))
 723                 return -EFAULT;
 724
 725         error = input_get_keycode(dev, &ke);
 726         if (error)
 727                 return error;
 728
 729         if (copy_to_user(p, &ke, sizeof(ke)))
 730                 return -EFAULT;
 731
 732         return 0;
 733 }
 734
 735 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
 736 {
 737         struct input_keymap_entry ke = {
 738                 .len    = sizeof(unsigned int),
 739                 .flags  = 0,
 740         };
 741         int __user *ip = (int __user *)p;
 742
 743         if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 744                 return -EFAULT;
 745
 746         if (get_user(ke.keycode, ip + 1))
 747                 return -EFAULT;
 748
 749         return input_set_keycode(dev, &ke);
 750 }
 751
 752 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
 753 {
 754         struct input_keymap_entry ke;
 755
 756         if (copy_from_user(&ke, p, sizeof(ke)))
 757                 return -EFAULT;
 758
 759         if (ke.len > sizeof(ke.scancode))
 760                 return -EINVAL;
 761
 762         return input_set_keycode(dev, &ke);
 763 }
 764
 765 /*
 766  * If we transfer state to the user, we should flush all pending events
 767  * of the same type from the client's queue. Otherwise, they might end up
 768  * with duplicate events, which can screw up client's state tracking.
 769  * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
 770  * event so user-space will notice missing events.
 771  *
 772  * LOCKING:
 773  * We need to take event_lock before buffer_lock to avoid dead-locks. But we
 774  * need the even_lock only to guarantee consistent state. We can safely release
 775  * it while flushing the queue. This allows input-core to handle filters while
 776  * we flush the queue.
 777  */
 778 static int evdev_handle_get_val(struct evdev_client *client,
 779                                 struct input_dev *dev, unsigned int type,
 780                                 unsigned long *bits, unsigned int maxbit,
 781                                 unsigned int maxlen, void __user *p,
 782                                 int compat)
 783 {
 784         int ret;
 785         unsigned long *mem;
 786         size_t len;
 787
 788         len = BITS_TO_LONGS(maxbit) * sizeof(unsigned long);
 789         mem = kmalloc(len, GFP_KERNEL);
 790         if (!mem)
 791                 return -ENOMEM;
 792
 793         spin_lock_irq(&dev->event_lock);
 794         spin_lock(&client->buffer_lock);
 795
 796         memcpy(mem, bits, len);
 797
 798         spin_unlock(&dev->event_lock);
 799
 800         __evdev_flush_queue(client, type);
 801
 802         spin_unlock_irq(&client->buffer_lock);
 803
 804         ret = bits_to_user(mem, maxbit, maxlen, p, compat);
 805         if (ret < 0)
 806                 evdev_queue_syn_dropped(client, false);
 807
 808         kfree(mem);
 809
 810         return ret;
 811 }
 812
 813 static int evdev_handle_mt_request(struct input_dev *dev,
 814                                    unsigned int size,
 815                                    int __user *ip)
 816 {
 817         const struct input_mt *mt = dev->mt;
 818         unsigned int code;
 819         int max_slots;
 820         int i;
 821
 822         if (get_user(code, &ip[0]))
 823                 return -EFAULT;
 824         if (!mt || !input_is_mt_value(code))
 825                 return -EINVAL;
 826
 827         max_slots = (size - sizeof(__u32)) / sizeof(__s32);
 828         for (i = 0; i < mt->num_slots && i < max_slots; i++) {
 829                 int value = input_mt_get_value(&mt->slots[i], code);
 830                 if (put_user(value, &ip[1 + i]))
 831                         return -EFAULT;
 832         }
 833
 834         return 0;
 835 }
 836
 837 static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
 838                         struct file *file)
 839 {
 840         client->revoked = true;
 841         evdev_ungrab(evdev, client);
 842         input_flush_device(&evdev->handle, file);
 843         wake_up_interruptible(&evdev->wait);
 844
 845         return 0;
 846 }
 847
 848 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 849                            void __user *p, int compat_mode)
 850 {
 851         struct evdev_client *client = file->private_data;
 852         struct evdev *evdev = client->evdev;
 853         struct input_dev *dev = evdev->handle.dev;
 854         struct input_absinfo abs;
 855         struct ff_effect effect;
 856         int __user *ip = (int __user *)p;
 857         unsigned int i, t, u, v;
 858         unsigned int size;
 859         int error;
 860
 861         /* First we check for fixed-length commands */
 862         switch (cmd) {
 863
 864         case EVIOCGVERSION:
 865                 return put_user(EV_VERSION, ip);
 866
 867         case EVIOCGID:
 868                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 869                         return -EFAULT;
 870                 return 0;
 871
 872         case EVIOCGREP:
 873                 if (!test_bit(EV_REP, dev->evbit))
 874                         return -ENOSYS;
 875                 if (put_user(dev->rep[REP_DELAY], ip))
 876                         return -EFAULT;
 877                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 878                         return -EFAULT;
 879                 return 0;
 880
 881         case EVIOCSREP:
 882                 if (!test_bit(EV_REP, dev->evbit))
 883                         return -ENOSYS;
 884                 if (get_user(u, ip))
 885                         return -EFAULT;
 886                 if (get_user(v, ip + 1))
 887                         return -EFAULT;
 888
 889                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 890                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 891
 892                 return 0;
 893
 894         case EVIOCRMFF:
 895                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 896
 897         case EVIOCGEFFECTS:
 898                 i = test_bit(EV_FF, dev->evbit) ?
 899                                 dev->ff->max_effects : 0;
 900                 if (put_user(i, ip))
 901                         return -EFAULT;
 902                 return 0;
 903
 904         case EVIOCGRAB:
 905                 if (p)
 906                         return evdev_grab(evdev, client);
 907                 else
 908                         return evdev_ungrab(evdev, client);
 909
 910         case EVIOCREVOKE:
 911                 if (p)
 912                         return -EINVAL;
 913                 else
 914                         return evdev_revoke(evdev, client, file);
 915
 916         case EVIOCSCLOCKID:
 917                 if (copy_from_user(&i, p, sizeof(unsigned int)))
 918                         return -EFAULT;
 919
 920                 return evdev_set_clk_type(client, i);
 921
 922         case EVIOCGKEYCODE:
 923                 return evdev_handle_get_keycode(dev, p);
 924
 925         case EVIOCSKEYCODE:
 926                 return evdev_handle_set_keycode(dev, p);
 927
 928         case EVIOCGKEYCODE_V2:
 929                 return evdev_handle_get_keycode_v2(dev, p);
 930
 931         case EVIOCSKEYCODE_V2:
 932                 return evdev_handle_set_keycode_v2(dev, p);
 933         }
 934
 935         size = _IOC_SIZE(cmd);
 936
 937         /* Now check variable-length commands */
 938 #define EVIOC_MASK_SIZE(nr)     ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
 939         switch (EVIOC_MASK_SIZE(cmd)) {
 940
 941         case EVIOCGPROP(0):
 942                 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
 943                                     size, p, compat_mode);
 944
 945         case EVIOCGMTSLOTS(0):
 946                 return evdev_handle_mt_request(dev, size, ip);
 947
 948         case EVIOCGKEY(0):
 949                 return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
 950                                             KEY_MAX, size, p, compat_mode);
 951
 952         case EVIOCGLED(0):
 953                 return evdev_handle_get_val(client, dev, EV_LED, dev->led,
 954                                             LED_MAX, size, p, compat_mode);
 955
 956         case EVIOCGSND(0):
 957                 return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
 958                                             SND_MAX, size, p, compat_mode);
 959
 960         case EVIOCGSW(0):
 961                 return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
 962                                             SW_MAX, size, p, compat_mode);
 963
 964         case EVIOCGNAME(0):
 965                 return str_to_user(dev->name, size, p);
 966
 967         case EVIOCGPHYS(0):
 968                 return str_to_user(dev->phys, size, p);
 969
 970         case EVIOCGUNIQ(0):
 971                 return str_to_user(dev->uniq, size, p);
 972
 973         case EVIOC_MASK_SIZE(EVIOCSFF):
 974                 if (input_ff_effect_from_user(p, size, &effect))
 975                         return -EFAULT;
 976
 977                 error = input_ff_upload(dev, &effect, file);
 978                 if (error)
 979                         return error;
 980
 981                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 982                         return -EFAULT;
 983
 984                 return 0;
 985         }
 986
 987         /* Multi-number variable-length handlers */
 988         if (_IOC_TYPE(cmd) != 'E')
 989                 return -EINVAL;
 990
 991         if (_IOC_DIR(cmd) == _IOC_READ) {
 992
 993                 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
 994                         return handle_eviocgbit(dev,
 995                                                 _IOC_NR(cmd) & EV_MAX, size,
 996                                                 p, compat_mode);
 997
 998                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 999
1000                         if (!dev->absinfo)
1001                                 return -EINVAL;
1002
1003                         t = _IOC_NR(cmd) & ABS_MAX;
1004                         abs = dev->absinfo[t];
1005
1006                         if (copy_to_user(p, &abs, min_t(size_t,
1007                                         size, sizeof(struct input_absinfo))))
1008                                 return -EFAULT;
1009
1010                         return 0;
1011                 }
1012         }
1013
1014         if (_IOC_DIR(cmd) == _IOC_WRITE) {
1015
1016                 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1017
1018                         if (!dev->absinfo)
1019                                 return -EINVAL;
1020
1021                         t = _IOC_NR(cmd) & ABS_MAX;
1022
1023                         if (copy_from_user(&abs, p, min_t(size_t,
1024                                         size, sizeof(struct input_absinfo))))
1025                                 return -EFAULT;
1026
1027                         if (size < sizeof(struct input_absinfo))
1028                                 abs.resolution = 0;
1029
1030                         /* We can't change number of reserved MT slots */
1031                         if (t == ABS_MT_SLOT)
1032                                 return -EINVAL;
1033
1034                         /*
1035                          * Take event lock to ensure that we are not
1036                          * changing device parameters in the middle
1037                          * of event.
1038                          */
1039                         spin_lock_irq(&dev->event_lock);
1040                         dev->absinfo[t] = abs;
1041                         spin_unlock_irq(&dev->event_lock);
1042
1043                         return 0;
1044                 }
1045         }
1046
1047         return -EINVAL;
1048 }
1049
1050 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1051                                 void __user *p, int compat_mode)
1052 {
1053         struct evdev_client *client = file->private_data;
1054         struct evdev *evdev = client->evdev;
1055         int retval;
1056
1057         retval = mutex_lock_interruptible(&evdev->mutex);
1058         if (retval)
1059                 return retval;
1060
1061         if (!evdev->exist || client->revoked) {
1062                 retval = -ENODEV;
1063                 goto out;
1064         }
1065
1066         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1067
1068  out:
1069         mutex_unlock(&evdev->mutex);
1070         return retval;
1071 }
1072
1073 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1074 {
1075         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1076 }
1077
1078 #ifdef CONFIG_COMPAT
1079 static long evdev_ioctl_compat(struct file *file,
1080                                 unsigned int cmd, unsigned long arg)
1081 {
1082         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1083 }
1084 #endif
1085
1086 static const struct file_operations evdev_fops = {
1087         .owner          = THIS_MODULE,
1088         .read           = evdev_read,
1089         .write          = evdev_write,
1090         .poll           = evdev_poll,
1091         .open           = evdev_open,
1092         .release        = evdev_release,
1093         .unlocked_ioctl = evdev_ioctl,
1094 #ifdef CONFIG_COMPAT
1095         .compat_ioctl   = evdev_ioctl_compat,
1096 #endif
1097         .fasync         = evdev_fasync,
1098         .flush          = evdev_flush,
1099         .llseek         = no_llseek,
1100 };
1101
1102 /*
1103  * Mark device non-existent. This disables writes, ioctls and
1104  * prevents new users from opening the device. Already posted
1105  * blocking reads will stay, however new ones will fail.
1106  */
1107 static void evdev_mark_dead(struct evdev *evdev)
1108 {
1109         mutex_lock(&evdev->mutex);
1110         evdev->exist = false;
1111         mutex_unlock(&evdev->mutex);
1112 }
1113
1114 static void evdev_cleanup(struct evdev *evdev)
1115 {
1116         struct input_handle *handle = &evdev->handle;
1117
1118         evdev_mark_dead(evdev);
1119         evdev_hangup(evdev);
1120
1121         cdev_del(&evdev->cdev);
1122
1123         /* evdev is marked dead so no one else accesses evdev->open */
1124         if (evdev->open) {
1125                 input_flush_device(handle, NULL);
1126                 input_close_device(handle);
1127         }
1128 }
1129
1130 /*
1131  * Create new evdev device. Note that input core serializes calls
1132  * to connect and disconnect.
1133  */
1134 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1135                          const struct input_device_id *id)
1136 {
1137         struct evdev *evdev;
1138         int minor;
1139         int dev_no;
1140         int error;
1141
1142         minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1143         if (minor < 0) {
1144                 error = minor;
1145                 pr_err("failed to reserve new minor: %d\n", error);
1146                 return error;
1147         }
1148
1149         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1150         if (!evdev) {
1151                 error = -ENOMEM;
1152                 goto err_free_minor;
1153         }
1154
1155         INIT_LIST_HEAD(&evdev->client_list);
1156         spin_lock_init(&evdev->client_lock);
1157         mutex_init(&evdev->mutex);
1158         init_waitqueue_head(&evdev->wait);
1159         evdev->exist = true;
1160
1161         dev_no = minor;
1162         /* Normalize device number if it falls into legacy range */
1163         if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1164                 dev_no -= EVDEV_MINOR_BASE;
1165         dev_set_name(&evdev->dev, "event%d", dev_no);
1166
1167         evdev->handle.dev = input_get_device(dev);
1168         evdev->handle.name = dev_name(&evdev->dev);
1169         evdev->handle.handler = handler;
1170         evdev->handle.private = evdev;
1171
1172         evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1173         evdev->dev.class = &input_class;
1174         evdev->dev.parent = &dev->dev;
1175         evdev->dev.release = evdev_free;
1176         device_initialize(&evdev->dev);
1177
1178         error = input_register_handle(&evdev->handle);
1179         if (error)
1180                 goto err_free_evdev;
1181
1182         cdev_init(&evdev->cdev, &evdev_fops);
1183         evdev->cdev.kobj.parent = &evdev->dev.kobj;
1184         error = cdev_add(&evdev->cdev, evdev->dev.devt, 1);
1185         if (error)
1186                 goto err_unregister_handle;
1187
1188         error = device_add(&evdev->dev);
1189         if (error)
1190                 goto err_cleanup_evdev;
1191
1192         return 0;
1193
1194  err_cleanup_evdev:
1195         evdev_cleanup(evdev);
1196  err_unregister_handle:
1197         input_unregister_handle(&evdev->handle);
1198  err_free_evdev:
1199         put_device(&evdev->dev);
1200  err_free_minor:
1201         input_free_minor(minor);
1202         return error;
1203 }
1204
1205 static void evdev_disconnect(struct input_handle *handle)
1206 {
1207         struct evdev *evdev = handle->private;
1208
1209         device_del(&evdev->dev);
1210         evdev_cleanup(evdev);
1211         input_free_minor(MINOR(evdev->dev.devt));
1212         input_unregister_handle(handle);
1213         put_device(&evdev->dev);
1214 }
1215
1216 static const struct input_device_id evdev_ids[] = {
1217         { .driver_info = 1 },   /* Matches all devices */
1218         { },                    /* Terminating zero entry */
1219 };
1220
1221 MODULE_DEVICE_TABLE(input, evdev_ids);
1222
1223 static struct input_handler evdev_handler = {
1224         .event          = evdev_event,
1225         .events         = evdev_events,
1226         .connect        = evdev_connect,
1227         .disconnect     = evdev_disconnect,
1228         .legacy_minors  = true,
1229         .minor          = EVDEV_MINOR_BASE,
1230         .name           = "evdev",
1231         .id_table       = evdev_ids,
1232 };
1233
1234 static int __init evdev_init(void)
1235 {
1236         return input_register_handler(&evdev_handler);
1237 }
1238
1239 static void __exit evdev_exit(void)
1240 {
1241         input_unregister_handler(&evdev_handler);
1242 }
1243
1244 module_init(evdev_init);
1245 module_exit(evdev_exit);
1246
1247 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1248 MODULE_DESCRIPTION("Input driver event char devices");
1249 MODULE_LICENSE("GPL");