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