1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Event char devices, giving access to raw input device events.
   4 *
   5 * Copyright (c) 1999-2002 Vojtech Pavlik
   6 */
   7
   8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10#define EVDEV_MINOR_BASE	64
  11#define EVDEV_MINORS		32
  12#define EVDEV_MIN_BUFFER_SIZE	64U
  13#define EVDEV_BUF_PACKETS	8
  14
  15#include <linux/poll.h>
  16#include <linux/sched.h>
  17#include <linux/slab.h>
  18#include <linux/vmalloc.h>
  19#include <linux/mm.h>
  20#include <linux/module.h>
  21#include <linux/init.h>
  22#include <linux/input/mt.h>
  23#include <linux/major.h>
  24#include <linux/device.h>
  25#include <linux/cdev.h>
  26#include "input-compat.h"
  27
  28struct evdev {
  29	int open;
  30	struct input_handle handle;
  31	struct evdev_client __rcu *grab;
  32	struct list_head client_list;
  33	spinlock_t client_lock; /* protects client_list */
  34	struct mutex mutex;
  35	struct device dev;
  36	struct cdev cdev;
  37	bool exist;
  38};
  39
  40struct evdev_client {
  41	unsigned int head;
  42	unsigned int tail;
  43	unsigned int packet_head; /* [future] position of the first element of next packet */
  44	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  45	wait_queue_head_t wait;
  46	struct fasync_struct *fasync;
  47	struct evdev *evdev;
  48	struct list_head node;
  49	enum input_clock_type clk_type;
  50	bool revoked;
  51	unsigned long *evmasks[EV_CNT];
  52	unsigned int bufsize;
  53	struct input_event buffer[] __counted_by(bufsize);
  54};
  55
  56static size_t evdev_get_mask_cnt(unsigned int type)
  57{
  58	static const size_t counts[EV_CNT] = {
  59		/* EV_SYN==0 is EV_CNT, _not_ SYN_CNT, see EVIOCGBIT */
  60		[EV_SYN]	= EV_CNT,
  61		[EV_KEY]	= KEY_CNT,
  62		[EV_REL]	= REL_CNT,
  63		[EV_ABS]	= ABS_CNT,
  64		[EV_MSC]	= MSC_CNT,
  65		[EV_SW]		= SW_CNT,
  66		[EV_LED]	= LED_CNT,
  67		[EV_SND]	= SND_CNT,
  68		[EV_FF]		= FF_CNT,
  69	};
  70
  71	return (type < EV_CNT) ? counts[type] : 0;
  72}
  73
  74/* requires the buffer lock to be held */
  75static bool __evdev_is_filtered(struct evdev_client *client,
  76				unsigned int type,
  77				unsigned int code)
  78{
  79	unsigned long *mask;
  80	size_t cnt;
  81
  82	/* EV_SYN and unknown codes are never filtered */
  83	if (type == EV_SYN || type >= EV_CNT)
  84		return false;
  85
  86	/* first test whether the type is filtered */
  87	mask = client->evmasks[0];
  88	if (mask && !test_bit(type, mask))
  89		return true;
  90
  91	/* unknown values are never filtered */
  92	cnt = evdev_get_mask_cnt(type);
  93	if (!cnt || code >= cnt)
  94		return false;
  95
  96	mask = client->evmasks[type];
  97	return mask && !test_bit(code, mask);
  98}
  99
 100/* flush queued events of type @type, caller must hold client->buffer_lock */
 101static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
 102{
 103	unsigned int i, head, num;
 104	unsigned int mask = client->bufsize - 1;
 105	bool is_report;
 106	struct input_event *ev;
 107
 108	BUG_ON(type == EV_SYN);
 109
 110	head = client->tail;
 111	client->packet_head = client->tail;
 112
 113	/* init to 1 so a leading SYN_REPORT will not be dropped */
 114	num = 1;
 115
 116	for (i = client->tail; i != client->head; i = (i + 1) & mask) {
 117		ev = &client->buffer[i];
 118		is_report = ev->type == EV_SYN && ev->code == SYN_REPORT;
 119
 120		if (ev->type == type) {
 121			/* drop matched entry */
 122			continue;
 123		} else if (is_report && !num) {
 124			/* drop empty SYN_REPORT groups */
 125			continue;
 126		} else if (head != i) {
 127			/* move entry to fill the gap */
 128			client->buffer[head] = *ev;
 129		}
 130
 131		num++;
 132		head = (head + 1) & mask;
 133
 134		if (is_report) {
 135			num = 0;
 136			client->packet_head = head;
 137		}
 138	}
 139
 140	client->head = head;
 141}
 142
 143static void __evdev_queue_syn_dropped(struct evdev_client *client)
 144{
 145	ktime_t *ev_time = input_get_timestamp(client->evdev->handle.dev);
 146	struct timespec64 ts = ktime_to_timespec64(ev_time[client->clk_type]);
 147	struct input_event ev;
 148
 149	ev.input_event_sec = ts.tv_sec;
 150	ev.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
 151	ev.type = EV_SYN;
 152	ev.code = SYN_DROPPED;
 153	ev.value = 0;
 154
 155	client->buffer[client->head++] = ev;
 156	client->head &= client->bufsize - 1;
 157
 158	if (unlikely(client->head == client->tail)) {
 159		/* drop queue but keep our SYN_DROPPED event */
 160		client->tail = (client->head - 1) & (client->bufsize - 1);
 161		client->packet_head = client->tail;
 162	}
 163}
 164
 165static void evdev_queue_syn_dropped(struct evdev_client *client)
 166{
 167	unsigned long flags;
 168
 169	spin_lock_irqsave(&client->buffer_lock, flags);
 170	__evdev_queue_syn_dropped(client);
 171	spin_unlock_irqrestore(&client->buffer_lock, flags);
 172}
 173
 174static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid)
 175{
 176	unsigned long flags;
 177	enum input_clock_type clk_type;
 178
 179	switch (clkid) {
 180
 181	case CLOCK_REALTIME:
 182		clk_type = INPUT_CLK_REAL;
 183		break;
 184	case CLOCK_MONOTONIC:
 185		clk_type = INPUT_CLK_MONO;
 186		break;
 187	case CLOCK_BOOTTIME:
 188		clk_type = INPUT_CLK_BOOT;
 189		break;
 190	default:
 191		return -EINVAL;
 192	}
 193
 194	if (client->clk_type != clk_type) {
 195		client->clk_type = clk_type;
 196
 197		/*
 198		 * Flush pending events and queue SYN_DROPPED event,
 199		 * but only if the queue is not empty.
 200		 */
 201		spin_lock_irqsave(&client->buffer_lock, flags);
 202
 203		if (client->head != client->tail) {
 204			client->packet_head = client->head = client->tail;
 205			__evdev_queue_syn_dropped(client);
 206		}
 207
 208		spin_unlock_irqrestore(&client->buffer_lock, flags);
 209	}
 210
 211	return 0;
 212}
 213
 214static void __pass_event(struct evdev_client *client,
 215			 const struct input_event *event)
 216{
 217	client->buffer[client->head++] = *event;
 218	client->head &= client->bufsize - 1;
 219
 220	if (unlikely(client->head == client->tail)) {
 221		/*
 222		 * This effectively "drops" all unconsumed events, leaving
 223		 * EV_SYN/SYN_DROPPED plus the newest event in the queue.
 224		 */
 225		client->tail = (client->head - 2) & (client->bufsize - 1);
 226
 227		client->buffer[client->tail] = (struct input_event) {
 228			.input_event_sec = event->input_event_sec,
 229			.input_event_usec = event->input_event_usec,
 230			.type = EV_SYN,
 231			.code = SYN_DROPPED,
 232			.value = 0,
 233		};
 234
 235		client->packet_head = client->tail;
 236	}
 237
 238	if (event->type == EV_SYN && event->code == SYN_REPORT) {
 239		client->packet_head = client->head;
 240		kill_fasync(&client->fasync, SIGIO, POLL_IN);
 241	}
 242}
 243
 244static void evdev_pass_values(struct evdev_client *client,
 245			const struct input_value *vals, unsigned int count,
 246			ktime_t *ev_time)
 247{
 248	const struct input_value *v;
 249	struct input_event event;
 250	struct timespec64 ts;
 251	bool wakeup = false;
 252
 253	if (client->revoked)
 254		return;
 255
 256	ts = ktime_to_timespec64(ev_time[client->clk_type]);
 257	event.input_event_sec = ts.tv_sec;
 258	event.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
 259
 260	/* Interrupts are disabled, just acquire the lock. */
 261	spin_lock(&client->buffer_lock);
 262
 263	for (v = vals; v != vals + count; v++) {
 264		if (__evdev_is_filtered(client, v->type, v->code))
 265			continue;
 266
 267		if (v->type == EV_SYN && v->code == SYN_REPORT) {
 268			/* drop empty SYN_REPORT */
 269			if (client->packet_head == client->head)
 270				continue;
 271
 272			wakeup = true;
 273		}
 274
 275		event.type = v->type;
 276		event.code = v->code;
 277		event.value = v->value;
 278		__pass_event(client, &event);
 279	}
 280
 281	spin_unlock(&client->buffer_lock);
 282
 283	if (wakeup)
 284		wake_up_interruptible_poll(&client->wait,
 285			EPOLLIN | EPOLLOUT | EPOLLRDNORM | EPOLLWRNORM);
 286}
 287
 288/*
 289 * Pass incoming events to all connected clients.
 290 */
 291static void evdev_events(struct input_handle *handle,
 292			 const struct input_value *vals, unsigned int count)
 293{
 294	struct evdev *evdev = handle->private;
 295	struct evdev_client *client;
 296	ktime_t *ev_time = input_get_timestamp(handle->dev);
 297
 298	rcu_read_lock();
 299
 300	client = rcu_dereference(evdev->grab);
 301
 302	if (client)
 303		evdev_pass_values(client, vals, count, ev_time);
 304	else
 305		list_for_each_entry_rcu(client, &evdev->client_list, node)
 306			evdev_pass_values(client, vals, count, ev_time);
 307
 308	rcu_read_unlock();
 309}
 310
 311/*
 312 * Pass incoming event to all connected clients.
 313 */
 314static void evdev_event(struct input_handle *handle,
 315			unsigned int type, unsigned int code, int value)
 316{
 317	struct input_value vals[] = { { type, code, value } };
 318
 319	evdev_events(handle, vals, 1);
 320}
 321
 322static int evdev_fasync(int fd, struct file *file, int on)
 323{
 324	struct evdev_client *client = file->private_data;
 325
 326	return fasync_helper(fd, file, on, &client->fasync);
 327}
 328
 329static void evdev_free(struct device *dev)
 330{
 331	struct evdev *evdev = container_of(dev, struct evdev, dev);
 332
 333	input_put_device(evdev->handle.dev);
 334	kfree(evdev);
 335}
 336
 337/*
 338 * Grabs an event device (along with underlying input device).
 339 * This function is called with evdev->mutex taken.
 340 */
 341static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 342{
 343	int error;
 344
 345	if (evdev->grab)
 346		return -EBUSY;
 347
 348	error = input_grab_device(&evdev->handle);
 349	if (error)
 350		return error;
 351
 352	rcu_assign_pointer(evdev->grab, client);
 353
 354	return 0;
 355}
 356
 357static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 358{
 359	struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
 360					lockdep_is_held(&evdev->mutex));
 361
 362	if (grab != client)
 363		return  -EINVAL;
 364
 365	rcu_assign_pointer(evdev->grab, NULL);
 366	synchronize_rcu();
 367	input_release_device(&evdev->handle);
 368
 369	return 0;
 370}
 371
 372static void evdev_attach_client(struct evdev *evdev,
 373				struct evdev_client *client)
 374{
 375	spin_lock(&evdev->client_lock);
 376	list_add_tail_rcu(&client->node, &evdev->client_list);
 377	spin_unlock(&evdev->client_lock);
 378}
 379
 380static void evdev_detach_client(struct evdev *evdev,
 381				struct evdev_client *client)
 382{
 383	spin_lock(&evdev->client_lock);
 384	list_del_rcu(&client->node);
 385	spin_unlock(&evdev->client_lock);
 386	synchronize_rcu();
 387}
 388
 389static int evdev_open_device(struct evdev *evdev)
 390{
 391	int retval;
 392
 393	retval = mutex_lock_interruptible(&evdev->mutex);
 394	if (retval)
 395		return retval;
 396
 397	if (!evdev->exist)
 398		retval = -ENODEV;
 399	else if (!evdev->open++) {
 400		retval = input_open_device(&evdev->handle);
 401		if (retval)
 402			evdev->open--;
 403	}
 404
 405	mutex_unlock(&evdev->mutex);
 406	return retval;
 407}
 408
 409static void evdev_close_device(struct evdev *evdev)
 410{
 411	mutex_lock(&evdev->mutex);
 412
 413	if (evdev->exist && !--evdev->open)
 414		input_close_device(&evdev->handle);
 415
 416	mutex_unlock(&evdev->mutex);
 417}
 418
 419/*
 420 * Wake up users waiting for IO so they can disconnect from
 421 * dead device.
 422 */
 423static void evdev_hangup(struct evdev *evdev)
 424{
 425	struct evdev_client *client;
 426
 427	spin_lock(&evdev->client_lock);
 428	list_for_each_entry(client, &evdev->client_list, node) {
 429		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 430		wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR);
 431	}
 432	spin_unlock(&evdev->client_lock);
 433}
 434
 435static int evdev_release(struct inode *inode, struct file *file)
 436{
 437	struct evdev_client *client = file->private_data;
 438	struct evdev *evdev = client->evdev;
 439	unsigned int i;
 440
 441	mutex_lock(&evdev->mutex);
 442
 443	if (evdev->exist && !client->revoked)
 444		input_flush_device(&evdev->handle, file);
 445
 446	evdev_ungrab(evdev, client);
 447	mutex_unlock(&evdev->mutex);
 448
 449	evdev_detach_client(evdev, client);
 450
 451	for (i = 0; i < EV_CNT; ++i)
 452		bitmap_free(client->evmasks[i]);
 453
 454	kvfree(client);
 455
 456	evdev_close_device(evdev);
 457
 458	return 0;
 459}
 460
 461static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
 462{
 463	unsigned int n_events =
 464		max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
 465		    EVDEV_MIN_BUFFER_SIZE);
 466
 467	return roundup_pow_of_two(n_events);
 468}
 469
 470static int evdev_open(struct inode *inode, struct file *file)
 471{
 472	struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
 473	unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
 474	struct evdev_client *client;
 475	int error;
 476
 477	client = kvzalloc(struct_size(client, buffer, bufsize), GFP_KERNEL);
 478	if (!client)
 479		return -ENOMEM;
 480
 481	init_waitqueue_head(&client->wait);
 482	client->bufsize = bufsize;
 483	spin_lock_init(&client->buffer_lock);
 484	client->evdev = evdev;
 485	evdev_attach_client(evdev, client);
 486
 487	error = evdev_open_device(evdev);
 488	if (error)
 489		goto err_free_client;
 490
 491	file->private_data = client;
 492	stream_open(inode, file);
 493
 494	return 0;
 495
 496 err_free_client:
 497	evdev_detach_client(evdev, client);
 498	kvfree(client);
 499	return error;
 500}
 501
 502static ssize_t evdev_write(struct file *file, const char __user *buffer,
 503			   size_t count, loff_t *ppos)
 504{
 505	struct evdev_client *client = file->private_data;
 506	struct evdev *evdev = client->evdev;
 507	struct input_event event;
 508	int retval = 0;
 509
 510	if (count != 0 && count < input_event_size())
 511		return -EINVAL;
 512
 513	retval = mutex_lock_interruptible(&evdev->mutex);
 514	if (retval)
 515		return retval;
 516
 517	if (!evdev->exist || client->revoked) {
 518		retval = -ENODEV;
 519		goto out;
 520	}
 521
 522	while (retval + input_event_size() <= count) {
 523
 524		if (input_event_from_user(buffer + retval, &event)) {
 525			retval = -EFAULT;
 526			goto out;
 527		}
 528		retval += input_event_size();
 529
 530		input_inject_event(&evdev->handle,
 531				   event.type, event.code, event.value);
 532		cond_resched();
 533	}
 534
 535 out:
 536	mutex_unlock(&evdev->mutex);
 537	return retval;
 538}
 539
 540static int evdev_fetch_next_event(struct evdev_client *client,
 541				  struct input_event *event)
 542{
 543	int have_event;
 544
 545	spin_lock_irq(&client->buffer_lock);
 546
 547	have_event = client->packet_head != client->tail;
 548	if (have_event) {
 549		*event = client->buffer[client->tail++];
 550		client->tail &= client->bufsize - 1;
 551	}
 552
 553	spin_unlock_irq(&client->buffer_lock);
 554
 555	return have_event;
 556}
 557
 558static ssize_t evdev_read(struct file *file, char __user *buffer,
 559			  size_t count, loff_t *ppos)
 560{
 561	struct evdev_client *client = file->private_data;
 562	struct evdev *evdev = client->evdev;
 563	struct input_event event;
 564	size_t read = 0;
 565	int error;
 566
 567	if (count != 0 && count < input_event_size())
 568		return -EINVAL;
 569
 570	for (;;) {
 571		if (!evdev->exist || client->revoked)
 572			return -ENODEV;
 573
 574		if (client->packet_head == client->tail &&
 575		    (file->f_flags & O_NONBLOCK))
 576			return -EAGAIN;
 577
 578		/*
 579		 * count == 0 is special - no IO is done but we check
 580		 * for error conditions (see above).
 581		 */
 582		if (count == 0)
 583			break;
 584
 585		while (read + input_event_size() <= count &&
 586		       evdev_fetch_next_event(client, &event)) {
 587
 588			if (input_event_to_user(buffer + read, &event))
 589				return -EFAULT;
 590
 591			read += input_event_size();
 592		}
 593
 594		if (read)
 595			break;
 596
 597		if (!(file->f_flags & O_NONBLOCK)) {
 598			error = wait_event_interruptible(client->wait,
 599					client->packet_head != client->tail ||
 600					!evdev->exist || client->revoked);
 601			if (error)
 602				return error;
 603		}
 604	}
 605
 606	return read;
 607}
 608
 609/* No kernel lock - fine */
 610static __poll_t evdev_poll(struct file *file, poll_table *wait)
 611{
 612	struct evdev_client *client = file->private_data;
 613	struct evdev *evdev = client->evdev;
 614	__poll_t mask;
 615
 616	poll_wait(file, &client->wait, wait);
 617
 618	if (evdev->exist && !client->revoked)
 619		mask = EPOLLOUT | EPOLLWRNORM;
 620	else
 621		mask = EPOLLHUP | EPOLLERR;
 622
 623	if (client->packet_head != client->tail)
 624		mask |= EPOLLIN | EPOLLRDNORM;
 625
 626	return mask;
 627}
 628
 629#ifdef CONFIG_COMPAT
 630
 631#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 632#define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 633
 634#ifdef __BIG_ENDIAN
 635static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 636			unsigned int maxlen, void __user *p, int compat)
 637{
 638	int len, i;
 639
 640	if (compat) {
 641		len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 642		if (len > maxlen)
 643			len = maxlen;
 644
 645		for (i = 0; i < len / sizeof(compat_long_t); i++)
 646			if (copy_to_user((compat_long_t __user *) p + i,
 647					 (compat_long_t *) bits +
 648						i + 1 - ((i % 2) << 1),
 649					 sizeof(compat_long_t)))
 650				return -EFAULT;
 651	} else {
 652		len = BITS_TO_LONGS(maxbit) * sizeof(long);
 653		if (len > maxlen)
 654			len = maxlen;
 655
 656		if (copy_to_user(p, bits, len))
 657			return -EFAULT;
 658	}
 659
 660	return len;
 661}
 662
 663static int bits_from_user(unsigned long *bits, unsigned int maxbit,
 664			  unsigned int maxlen, const void __user *p, int compat)
 665{
 666	int len, i;
 667
 668	if (compat) {
 669		if (maxlen % sizeof(compat_long_t))
 670			return -EINVAL;
 671
 672		len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 673		if (len > maxlen)
 674			len = maxlen;
 675
 676		for (i = 0; i < len / sizeof(compat_long_t); i++)
 677			if (copy_from_user((compat_long_t *) bits +
 678						i + 1 - ((i % 2) << 1),
 679					   (compat_long_t __user *) p + i,
 680					   sizeof(compat_long_t)))
 681				return -EFAULT;
 682		if (i % 2)
 683			*((compat_long_t *) bits + i - 1) = 0;
 684
 685	} else {
 686		if (maxlen % sizeof(long))
 687			return -EINVAL;
 688
 689		len = BITS_TO_LONGS(maxbit) * sizeof(long);
 690		if (len > maxlen)
 691			len = maxlen;
 692
 693		if (copy_from_user(bits, p, len))
 694			return -EFAULT;
 695	}
 696
 697	return len;
 698}
 699
 700#else
 701
 702static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 703			unsigned int maxlen, void __user *p, int compat)
 704{
 705	int len = compat ?
 706			BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 707			BITS_TO_LONGS(maxbit) * sizeof(long);
 708
 709	if (len > maxlen)
 710		len = maxlen;
 711
 712	return copy_to_user(p, bits, len) ? -EFAULT : len;
 713}
 714
 715static int bits_from_user(unsigned long *bits, unsigned int maxbit,
 716			  unsigned int maxlen, const void __user *p, int compat)
 717{
 718	size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long);
 719	int len;
 720
 721	if (maxlen % chunk_size)
 722		return -EINVAL;
 723
 724	len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);
 725	len *= chunk_size;
 726	if (len > maxlen)
 727		len = maxlen;
 728
 729	return copy_from_user(bits, p, len) ? -EFAULT : len;
 730}
 731
 732#endif /* __BIG_ENDIAN */
 733
 734#else
 735
 736static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 737			unsigned int maxlen, void __user *p, int compat)
 738{
 739	int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 740
 741	if (len > maxlen)
 742		len = maxlen;
 743
 744	return copy_to_user(p, bits, len) ? -EFAULT : len;
 745}
 746
 747static int bits_from_user(unsigned long *bits, unsigned int maxbit,
 748			  unsigned int maxlen, const void __user *p, int compat)
 749{
 750	int len;
 751
 752	if (maxlen % sizeof(long))
 753		return -EINVAL;
 754
 755	len = BITS_TO_LONGS(maxbit) * sizeof(long);
 756	if (len > maxlen)
 757		len = maxlen;
 758
 759	return copy_from_user(bits, p, len) ? -EFAULT : len;
 760}
 761
 762#endif /* CONFIG_COMPAT */
 763
 764static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 765{
 766	int len;
 767
 768	if (!str)
 769		return -ENOENT;
 770
 771	len = strlen(str) + 1;
 772	if (len > maxlen)
 773		len = maxlen;
 774
 775	return copy_to_user(p, str, len) ? -EFAULT : len;
 776}
 777
 778static int handle_eviocgbit(struct input_dev *dev,
 779			    unsigned int type, unsigned int size,
 780			    void __user *p, int compat_mode)
 781{
 782	unsigned long *bits;
 783	int len;
 784
 785	switch (type) {
 786
 787	case      0: bits = dev->evbit;  len = EV_MAX;  break;
 788	case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 789	case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 790	case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 791	case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 792	case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 793	case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 794	case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 795	case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 796	default: return -EINVAL;
 797	}
 798
 799	return bits_to_user(bits, len, size, p, compat_mode);
 800}
 801
 802static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
 803{
 804	struct input_keymap_entry ke = {
 805		.len	= sizeof(unsigned int),
 806		.flags	= 0,
 807	};
 808	int __user *ip = (int __user *)p;
 809	int error;
 810
 811	/* legacy case */
 812	if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 813		return -EFAULT;
 814
 815	error = input_get_keycode(dev, &ke);
 816	if (error)
 817		return error;
 818
 819	if (put_user(ke.keycode, ip + 1))
 820		return -EFAULT;
 821
 822	return 0;
 823}
 824
 825static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
 826{
 827	struct input_keymap_entry ke;
 828	int error;
 829
 830	if (copy_from_user(&ke, p, sizeof(ke)))
 831		return -EFAULT;
 832
 833	error = input_get_keycode(dev, &ke);
 834	if (error)
 835		return error;
 836
 837	if (copy_to_user(p, &ke, sizeof(ke)))
 838		return -EFAULT;
 839
 840	return 0;
 841}
 842
 843static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
 844{
 845	struct input_keymap_entry ke = {
 846		.len	= sizeof(unsigned int),
 847		.flags	= 0,
 848	};
 849	int __user *ip = (int __user *)p;
 850
 851	if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
 852		return -EFAULT;
 853
 854	if (get_user(ke.keycode, ip + 1))
 855		return -EFAULT;
 856
 857	return input_set_keycode(dev, &ke);
 858}
 859
 860static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
 861{
 862	struct input_keymap_entry ke;
 863
 864	if (copy_from_user(&ke, p, sizeof(ke)))
 865		return -EFAULT;
 866
 867	if (ke.len > sizeof(ke.scancode))
 868		return -EINVAL;
 869
 870	return input_set_keycode(dev, &ke);
 871}
 872
 873/*
 874 * If we transfer state to the user, we should flush all pending events
 875 * of the same type from the client's queue. Otherwise, they might end up
 876 * with duplicate events, which can screw up client's state tracking.
 877 * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
 878 * event so user-space will notice missing events.
 879 *
 880 * LOCKING:
 881 * We need to take event_lock before buffer_lock to avoid dead-locks. But we
 882 * need the even_lock only to guarantee consistent state. We can safely release
 883 * it while flushing the queue. This allows input-core to handle filters while
 884 * we flush the queue.
 885 */
 886static int evdev_handle_get_val(struct evdev_client *client,
 887				struct input_dev *dev, unsigned int type,
 888				unsigned long *bits, unsigned int maxbit,
 889				unsigned int maxlen, void __user *p,
 890				int compat)
 891{
 892	int ret;
 893	unsigned long *mem;
 894
 895	mem = bitmap_alloc(maxbit, GFP_KERNEL);
 896	if (!mem)
 897		return -ENOMEM;
 898
 899	spin_lock_irq(&dev->event_lock);
 900	spin_lock(&client->buffer_lock);
 901
 902	bitmap_copy(mem, bits, maxbit);
 903
 904	spin_unlock(&dev->event_lock);
 905
 906	__evdev_flush_queue(client, type);
 907
 908	spin_unlock_irq(&client->buffer_lock);
 909
 910	ret = bits_to_user(mem, maxbit, maxlen, p, compat);
 911	if (ret < 0)
 912		evdev_queue_syn_dropped(client);
 913
 914	bitmap_free(mem);
 915
 916	return ret;
 917}
 918
 919static int evdev_handle_mt_request(struct input_dev *dev,
 920				   unsigned int size,
 921				   int __user *ip)
 922{
 923	const struct input_mt *mt = dev->mt;
 924	unsigned int code;
 925	int max_slots;
 926	int i;
 927
 928	if (get_user(code, &ip[0]))
 929		return -EFAULT;
 930	if (!mt || !input_is_mt_value(code))
 931		return -EINVAL;
 932
 933	max_slots = (size - sizeof(__u32)) / sizeof(__s32);
 934	for (i = 0; i < mt->num_slots && i < max_slots; i++) {
 935		int value = input_mt_get_value(&mt->slots[i], code);
 936		if (put_user(value, &ip[1 + i]))
 937			return -EFAULT;
 938	}
 939
 940	return 0;
 941}
 942
 943static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
 944			struct file *file)
 945{
 946	client->revoked = true;
 947	evdev_ungrab(evdev, client);
 948	input_flush_device(&evdev->handle, file);
 949	wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR);
 950
 951	return 0;
 952}
 953
 954/* must be called with evdev-mutex held */
 955static int evdev_set_mask(struct evdev_client *client,
 956			  unsigned int type,
 957			  const void __user *codes,
 958			  u32 codes_size,
 959			  int compat)
 960{
 961	unsigned long flags, *mask, *oldmask;
 962	size_t cnt;
 963	int error;
 964
 965	/* we allow unknown types and 'codes_size > size' for forward-compat */
 966	cnt = evdev_get_mask_cnt(type);
 967	if (!cnt)
 968		return 0;
 969
 970	mask = bitmap_zalloc(cnt, GFP_KERNEL);
 971	if (!mask)
 972		return -ENOMEM;
 973
 974	error = bits_from_user(mask, cnt - 1, codes_size, codes, compat);
 975	if (error < 0) {
 976		bitmap_free(mask);
 977		return error;
 978	}
 979
 980	spin_lock_irqsave(&client->buffer_lock, flags);
 981	oldmask = client->evmasks[type];
 982	client->evmasks[type] = mask;
 983	spin_unlock_irqrestore(&client->buffer_lock, flags);
 984
 985	bitmap_free(oldmask);
 986
 987	return 0;
 988}
 989
 990/* must be called with evdev-mutex held */
 991static int evdev_get_mask(struct evdev_client *client,
 992			  unsigned int type,
 993			  void __user *codes,
 994			  u32 codes_size,
 995			  int compat)
 996{
 997	unsigned long *mask;
 998	size_t cnt, size, xfer_size;
 999	int i;
1000	int error;
1001
1002	/* we allow unknown types and 'codes_size > size' for forward-compat */
1003	cnt = evdev_get_mask_cnt(type);
1004	size = sizeof(unsigned long) * BITS_TO_LONGS(cnt);
1005	xfer_size = min_t(size_t, codes_size, size);
1006
1007	if (cnt > 0) {
1008		mask = client->evmasks[type];
1009		if (mask) {
1010			error = bits_to_user(mask, cnt - 1,
1011					     xfer_size, codes, compat);
1012			if (error < 0)
1013				return error;
1014		} else {
1015			/* fake mask with all bits set */
1016			for (i = 0; i < xfer_size; i++)
1017				if (put_user(0xffU, (u8 __user *)codes + i))
1018					return -EFAULT;
1019		}
1020	}
1021
1022	if (xfer_size < codes_size)
1023		if (clear_user(codes + xfer_size, codes_size - xfer_size))
1024			return -EFAULT;
1025
1026	return 0;
1027}
1028
1029static long evdev_do_ioctl(struct file *file, unsigned int cmd,
1030			   void __user *p, int compat_mode)
1031{
1032	struct evdev_client *client = file->private_data;
1033	struct evdev *evdev = client->evdev;
1034	struct input_dev *dev = evdev->handle.dev;
1035	struct input_absinfo abs;
1036	struct input_mask mask;
1037	struct ff_effect effect;
1038	int __user *ip = (int __user *)p;
1039	unsigned int i, t, u, v;
1040	unsigned int size;
1041	int error;
1042
1043	/* First we check for fixed-length commands */
1044	switch (cmd) {
1045
1046	case EVIOCGVERSION:
1047		return put_user(EV_VERSION, ip);
1048
1049	case EVIOCGID:
1050		if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
1051			return -EFAULT;
1052		return 0;
1053
1054	case EVIOCGREP:
1055		if (!test_bit(EV_REP, dev->evbit))
1056			return -ENOSYS;
1057		if (put_user(dev->rep[REP_DELAY], ip))
1058			return -EFAULT;
1059		if (put_user(dev->rep[REP_PERIOD], ip + 1))
1060			return -EFAULT;
1061		return 0;
1062
1063	case EVIOCSREP:
1064		if (!test_bit(EV_REP, dev->evbit))
1065			return -ENOSYS;
1066		if (get_user(u, ip))
1067			return -EFAULT;
1068		if (get_user(v, ip + 1))
1069			return -EFAULT;
1070
1071		input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
1072		input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
1073
1074		return 0;
1075
1076	case EVIOCRMFF:
1077		return input_ff_erase(dev, (int)(unsigned long) p, file);
1078
1079	case EVIOCGEFFECTS:
1080		i = test_bit(EV_FF, dev->evbit) ?
1081				dev->ff->max_effects : 0;
1082		if (put_user(i, ip))
1083			return -EFAULT;
1084		return 0;
1085
1086	case EVIOCGRAB:
1087		if (p)
1088			return evdev_grab(evdev, client);
1089		else
1090			return evdev_ungrab(evdev, client);
1091
1092	case EVIOCREVOKE:
1093		if (p)
1094			return -EINVAL;
1095		else
1096			return evdev_revoke(evdev, client, file);
1097
1098	case EVIOCGMASK: {
1099		void __user *codes_ptr;
1100
1101		if (copy_from_user(&mask, p, sizeof(mask)))
1102			return -EFAULT;
1103
1104		codes_ptr = (void __user *)(unsigned long)mask.codes_ptr;
1105		return evdev_get_mask(client,
1106				      mask.type, codes_ptr, mask.codes_size,
1107				      compat_mode);
1108	}
1109
1110	case EVIOCSMASK: {
1111		const void __user *codes_ptr;
1112
1113		if (copy_from_user(&mask, p, sizeof(mask)))
1114			return -EFAULT;
1115
1116		codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr;
1117		return evdev_set_mask(client,
1118				      mask.type, codes_ptr, mask.codes_size,
1119				      compat_mode);
1120	}
1121
1122	case EVIOCSCLOCKID:
1123		if (copy_from_user(&i, p, sizeof(unsigned int)))
1124			return -EFAULT;
1125
1126		return evdev_set_clk_type(client, i);
1127
1128	case EVIOCGKEYCODE:
1129		return evdev_handle_get_keycode(dev, p);
1130
1131	case EVIOCSKEYCODE:
1132		return evdev_handle_set_keycode(dev, p);
1133
1134	case EVIOCGKEYCODE_V2:
1135		return evdev_handle_get_keycode_v2(dev, p);
1136
1137	case EVIOCSKEYCODE_V2:
1138		return evdev_handle_set_keycode_v2(dev, p);
1139	}
1140
1141	size = _IOC_SIZE(cmd);
1142
1143	/* Now check variable-length commands */
1144#define EVIOC_MASK_SIZE(nr)	((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
1145	switch (EVIOC_MASK_SIZE(cmd)) {
1146
1147	case EVIOCGPROP(0):
1148		return bits_to_user(dev->propbit, INPUT_PROP_MAX,
1149				    size, p, compat_mode);
1150
1151	case EVIOCGMTSLOTS(0):
1152		return evdev_handle_mt_request(dev, size, ip);
1153
1154	case EVIOCGKEY(0):
1155		return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
1156					    KEY_MAX, size, p, compat_mode);
1157
1158	case EVIOCGLED(0):
1159		return evdev_handle_get_val(client, dev, EV_LED, dev->led,
1160					    LED_MAX, size, p, compat_mode);
1161
1162	case EVIOCGSND(0):
1163		return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
1164					    SND_MAX, size, p, compat_mode);
1165
1166	case EVIOCGSW(0):
1167		return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
1168					    SW_MAX, size, p, compat_mode);
1169
1170	case EVIOCGNAME(0):
1171		return str_to_user(dev->name, size, p);
1172
1173	case EVIOCGPHYS(0):
1174		return str_to_user(dev->phys, size, p);
1175
1176	case EVIOCGUNIQ(0):
1177		return str_to_user(dev->uniq, size, p);
1178
1179	case EVIOC_MASK_SIZE(EVIOCSFF):
1180		if (input_ff_effect_from_user(p, size, &effect))
1181			return -EFAULT;
1182
1183		error = input_ff_upload(dev, &effect, file);
1184		if (error)
1185			return error;
1186
1187		if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
1188			return -EFAULT;
1189
1190		return 0;
1191	}
1192
1193	/* Multi-number variable-length handlers */
1194	if (_IOC_TYPE(cmd) != 'E')
1195		return -EINVAL;
1196
1197	if (_IOC_DIR(cmd) == _IOC_READ) {
1198
1199		if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
1200			return handle_eviocgbit(dev,
1201						_IOC_NR(cmd) & EV_MAX, size,
1202						p, compat_mode);
1203
1204		if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1205
1206			if (!dev->absinfo)
1207				return -EINVAL;
1208
1209			t = _IOC_NR(cmd) & ABS_MAX;
1210			abs = dev->absinfo[t];
1211
1212			if (copy_to_user(p, &abs, min_t(size_t,
1213					size, sizeof(struct input_absinfo))))
1214				return -EFAULT;
1215
1216			return 0;
1217		}
1218	}
1219
1220	if (_IOC_DIR(cmd) == _IOC_WRITE) {
1221
1222		if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1223
1224			if (!dev->absinfo)
1225				return -EINVAL;
1226
1227			t = _IOC_NR(cmd) & ABS_MAX;
1228
1229			if (copy_from_user(&abs, p, min_t(size_t,
1230					size, sizeof(struct input_absinfo))))
1231				return -EFAULT;
1232
1233			if (size < sizeof(struct input_absinfo))
1234				abs.resolution = 0;
1235
1236			/* We can't change number of reserved MT slots */
1237			if (t == ABS_MT_SLOT)
1238				return -EINVAL;
1239
1240			/*
1241			 * Take event lock to ensure that we are not
1242			 * changing device parameters in the middle
1243			 * of event.
1244			 */
1245			spin_lock_irq(&dev->event_lock);
1246			dev->absinfo[t] = abs;
1247			spin_unlock_irq(&dev->event_lock);
1248
1249			return 0;
1250		}
1251	}
1252
1253	return -EINVAL;
1254}
1255
1256static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1257				void __user *p, int compat_mode)
1258{
1259	struct evdev_client *client = file->private_data;
1260	struct evdev *evdev = client->evdev;
1261	int retval;
1262
1263	retval = mutex_lock_interruptible(&evdev->mutex);
1264	if (retval)
1265		return retval;
1266
1267	if (!evdev->exist || client->revoked) {
1268		retval = -ENODEV;
1269		goto out;
1270	}
1271
1272	retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1273
1274 out:
1275	mutex_unlock(&evdev->mutex);
1276	return retval;
1277}
1278
1279static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1280{
1281	return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1282}
1283
1284#ifdef CONFIG_COMPAT
1285static long evdev_ioctl_compat(struct file *file,
1286				unsigned int cmd, unsigned long arg)
1287{
1288	return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1289}
1290#endif
1291
1292static const struct file_operations evdev_fops = {
1293	.owner		= THIS_MODULE,
1294	.read		= evdev_read,
1295	.write		= evdev_write,
1296	.poll		= evdev_poll,
1297	.open		= evdev_open,
1298	.release	= evdev_release,
1299	.unlocked_ioctl	= evdev_ioctl,
1300#ifdef CONFIG_COMPAT
1301	.compat_ioctl	= evdev_ioctl_compat,
1302#endif
1303	.fasync		= evdev_fasync,
1304	.llseek		= no_llseek,
1305};
1306
1307/*
1308 * Mark device non-existent. This disables writes, ioctls and
1309 * prevents new users from opening the device. Already posted
1310 * blocking reads will stay, however new ones will fail.
1311 */
1312static void evdev_mark_dead(struct evdev *evdev)
1313{
1314	mutex_lock(&evdev->mutex);
1315	evdev->exist = false;
1316	mutex_unlock(&evdev->mutex);
1317}
1318
1319static void evdev_cleanup(struct evdev *evdev)
1320{
1321	struct input_handle *handle = &evdev->handle;
1322
1323	evdev_mark_dead(evdev);
1324	evdev_hangup(evdev);
1325
1326	/* evdev is marked dead so no one else accesses evdev->open */
1327	if (evdev->open) {
1328		input_flush_device(handle, NULL);
1329		input_close_device(handle);
1330	}
1331}
1332
1333/*
1334 * Create new evdev device. Note that input core serializes calls
1335 * to connect and disconnect.
1336 */
1337static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1338			 const struct input_device_id *id)
1339{
1340	struct evdev *evdev;
1341	int minor;
1342	int dev_no;
1343	int error;
1344
1345	minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1346	if (minor < 0) {
1347		error = minor;
1348		pr_err("failed to reserve new minor: %d\n", error);
1349		return error;
1350	}
1351
1352	evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
1353	if (!evdev) {
1354		error = -ENOMEM;
1355		goto err_free_minor;
1356	}
1357
1358	INIT_LIST_HEAD(&evdev->client_list);
1359	spin_lock_init(&evdev->client_lock);
1360	mutex_init(&evdev->mutex);
1361	evdev->exist = true;
1362
1363	dev_no = minor;
1364	/* Normalize device number if it falls into legacy range */
1365	if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1366		dev_no -= EVDEV_MINOR_BASE;
1367	dev_set_name(&evdev->dev, "event%d", dev_no);
1368
1369	evdev->handle.dev = input_get_device(dev);
1370	evdev->handle.name = dev_name(&evdev->dev);
1371	evdev->handle.handler = handler;
1372	evdev->handle.private = evdev;
1373
1374	evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1375	evdev->dev.class = &input_class;
1376	evdev->dev.parent = &dev->dev;
1377	evdev->dev.release = evdev_free;
1378	device_initialize(&evdev->dev);
1379
1380	error = input_register_handle(&evdev->handle);
1381	if (error)
1382		goto err_free_evdev;
1383
1384	cdev_init(&evdev->cdev, &evdev_fops);
1385
1386	error = cdev_device_add(&evdev->cdev, &evdev->dev);
1387	if (error)
1388		goto err_cleanup_evdev;
1389
1390	return 0;
1391
1392 err_cleanup_evdev:
1393	evdev_cleanup(evdev);
1394	input_unregister_handle(&evdev->handle);
1395 err_free_evdev:
1396	put_device(&evdev->dev);
1397 err_free_minor:
1398	input_free_minor(minor);
1399	return error;
1400}
1401
1402static void evdev_disconnect(struct input_handle *handle)
1403{
1404	struct evdev *evdev = handle->private;
1405
1406	cdev_device_del(&evdev->cdev, &evdev->dev);
1407	evdev_cleanup(evdev);
1408	input_free_minor(MINOR(evdev->dev.devt));
1409	input_unregister_handle(handle);
1410	put_device(&evdev->dev);
1411}
1412
1413static const struct input_device_id evdev_ids[] = {
1414	{ .driver_info = 1 },	/* Matches all devices */
1415	{ },			/* Terminating zero entry */
1416};
1417
1418MODULE_DEVICE_TABLE(input, evdev_ids);
1419
1420static struct input_handler evdev_handler = {
1421	.event		= evdev_event,
1422	.events		= evdev_events,
1423	.connect	= evdev_connect,
1424	.disconnect	= evdev_disconnect,
1425	.legacy_minors	= true,
1426	.minor		= EVDEV_MINOR_BASE,
1427	.name		= "evdev",
1428	.id_table	= evdev_ids,
1429};
1430
1431static int __init evdev_init(void)
1432{
1433	return input_register_handler(&evdev_handler);
1434}
1435
1436static void __exit evdev_exit(void)
1437{
1438	input_unregister_handler(&evdev_handler);
1439}
1440
1441module_init(evdev_init);
1442module_exit(evdev_exit);
1443
1444MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
1445MODULE_DESCRIPTION("Input driver event char devices");
1446MODULE_LICENSE("GPL");