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 28 struct 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 40 struct 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 56 static 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 */ 75 static 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 */ 101 static 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 } 142 143 static 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 } 164 165 static 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 } 173 174 static 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 } 213 214 static 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 } 243 244 static 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 */ 291 static unsigned int evdev_events(struct input_handle *handle, 292 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 return count; 311 } 312 313 static int evdev_fasync(int fd, struct file *file, int on) 314 { 315 struct evdev_client *client = file->private_data; 316 317 return fasync_helper(fd, file, on, &client->fasync); 318 } 319 320 static void evdev_free(struct device *dev) 321 { 322 struct evdev *evdev = container_of(dev, struct evdev, dev); 323 324 input_put_device(evdev->handle.dev); 325 kfree(evdev); 326 } 327 328 /* 329 * Grabs an event device (along with underlying input device). 330 * This function is called with evdev->mutex taken. 331 */ 332 static int evdev_grab(struct evdev *evdev, struct evdev_client *client) 333 { 334 int error; 335 336 if (evdev->grab) 337 return -EBUSY; 338 339 error = input_grab_device(&evdev->handle); 340 if (error) 341 return error; 342 343 rcu_assign_pointer(evdev->grab, client); 344 345 return 0; 346 } 347 348 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client) 349 { 350 struct evdev_client *grab = rcu_dereference_protected(evdev->grab, 351 lockdep_is_held(&evdev->mutex)); 352 353 if (grab != client) 354 return -EINVAL; 355 356 rcu_assign_pointer(evdev->grab, NULL); 357 synchronize_rcu(); 358 input_release_device(&evdev->handle); 359 360 return 0; 361 } 362 363 static void evdev_attach_client(struct evdev *evdev, 364 struct evdev_client *client) 365 { 366 spin_lock(&evdev->client_lock); 367 list_add_tail_rcu(&client->node, &evdev->client_list); 368 spin_unlock(&evdev->client_lock); 369 } 370 371 static void evdev_detach_client(struct evdev *evdev, 372 struct evdev_client *client) 373 { 374 spin_lock(&evdev->client_lock); 375 list_del_rcu(&client->node); 376 spin_unlock(&evdev->client_lock); 377 synchronize_rcu(); 378 } 379 380 static int evdev_open_device(struct evdev *evdev) 381 { 382 int retval; 383 384 retval = mutex_lock_interruptible(&evdev->mutex); 385 if (retval) 386 return retval; 387 388 if (!evdev->exist) 389 retval = -ENODEV; 390 else if (!evdev->open++) { 391 retval = input_open_device(&evdev->handle); 392 if (retval) 393 evdev->open--; 394 } 395 396 mutex_unlock(&evdev->mutex); 397 return retval; 398 } 399 400 static void evdev_close_device(struct evdev *evdev) 401 { 402 mutex_lock(&evdev->mutex); 403 404 if (evdev->exist && !--evdev->open) 405 input_close_device(&evdev->handle); 406 407 mutex_unlock(&evdev->mutex); 408 } 409 410 /* 411 * Wake up users waiting for IO so they can disconnect from 412 * dead device. 413 */ 414 static void evdev_hangup(struct evdev *evdev) 415 { 416 struct evdev_client *client; 417 418 spin_lock(&evdev->client_lock); 419 list_for_each_entry(client, &evdev->client_list, node) { 420 kill_fasync(&client->fasync, SIGIO, POLL_HUP); 421 wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR); 422 } 423 spin_unlock(&evdev->client_lock); 424 } 425 426 static int evdev_release(struct inode *inode, struct file *file) 427 { 428 struct evdev_client *client = file->private_data; 429 struct evdev *evdev = client->evdev; 430 unsigned int i; 431 432 mutex_lock(&evdev->mutex); 433 434 if (evdev->exist && !client->revoked) 435 input_flush_device(&evdev->handle, file); 436 437 evdev_ungrab(evdev, client); 438 mutex_unlock(&evdev->mutex); 439 440 evdev_detach_client(evdev, client); 441 442 for (i = 0; i < EV_CNT; ++i) 443 bitmap_free(client->evmasks[i]); 444 445 kvfree(client); 446 447 evdev_close_device(evdev); 448 449 return 0; 450 } 451 452 static unsigned int evdev_compute_buffer_size(struct input_dev *dev) 453 { 454 unsigned int n_events = 455 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS, 456 EVDEV_MIN_BUFFER_SIZE); 457 458 return roundup_pow_of_two(n_events); 459 } 460 461 static int evdev_open(struct inode *inode, struct file *file) 462 { 463 struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev); 464 unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev); 465 struct evdev_client *client; 466 int error; 467 468 client = kvzalloc(struct_size(client, buffer, bufsize), GFP_KERNEL); 469 if (!client) 470 return -ENOMEM; 471 472 init_waitqueue_head(&client->wait); 473 client->bufsize = bufsize; 474 spin_lock_init(&client->buffer_lock); 475 client->evdev = evdev; 476 evdev_attach_client(evdev, client); 477 478 error = evdev_open_device(evdev); 479 if (error) 480 goto err_free_client; 481 482 file->private_data = client; 483 stream_open(inode, file); 484 485 return 0; 486 487 err_free_client: 488 evdev_detach_client(evdev, client); 489 kvfree(client); 490 return error; 491 } 492 493 static ssize_t evdev_write(struct file *file, const char __user *buffer, 494 size_t count, loff_t *ppos) 495 { 496 struct evdev_client *client = file->private_data; 497 struct evdev *evdev = client->evdev; 498 struct input_event event; 499 int retval = 0; 500 501 /* 502 * Limit amount of data we inject into the input subsystem so that 503 * we do not hold evdev->mutex for too long. 4096 bytes corresponds 504 * to 170 input events. 505 */ 506 count = min(count, 4096); 507 508 if (count != 0 && count < input_event_size()) 509 return -EINVAL; 510 511 retval = mutex_lock_interruptible(&evdev->mutex); 512 if (retval) 513 return retval; 514 515 if (!evdev->exist || client->revoked) { 516 retval = -ENODEV; 517 goto out; 518 } 519 520 while (retval + input_event_size() <= count) { 521 522 if (input_event_from_user(buffer + retval, &event)) { 523 retval = -EFAULT; 524 goto out; 525 } 526 retval += input_event_size(); 527 528 input_inject_event(&evdev->handle, 529 event.type, event.code, event.value); 530 cond_resched(); 531 } 532 533 out: 534 mutex_unlock(&evdev->mutex); 535 return retval; 536 } 537 538 static int evdev_fetch_next_event(struct evdev_client *client, 539 struct input_event *event) 540 { 541 int have_event; 542 543 spin_lock_irq(&client->buffer_lock); 544 545 have_event = client->packet_head != client->tail; 546 if (have_event) { 547 *event = client->buffer[client->tail++]; 548 client->tail &= client->bufsize - 1; 549 } 550 551 spin_unlock_irq(&client->buffer_lock); 552 553 return have_event; 554 } 555 556 static ssize_t evdev_read(struct file *file, char __user *buffer, 557 size_t count, loff_t *ppos) 558 { 559 struct evdev_client *client = file->private_data; 560 struct evdev *evdev = client->evdev; 561 struct input_event event; 562 size_t read = 0; 563 int error; 564 565 if (count != 0 && count < input_event_size()) 566 return -EINVAL; 567 568 for (;;) { 569 if (!evdev->exist || client->revoked) 570 return -ENODEV; 571 572 if (client->packet_head == client->tail && 573 (file->f_flags & O_NONBLOCK)) 574 return -EAGAIN; 575 576 /* 577 * count == 0 is special - no IO is done but we check 578 * for error conditions (see above). 579 */ 580 if (count == 0) 581 break; 582 583 while (read + input_event_size() <= count && 584 evdev_fetch_next_event(client, &event)) { 585 586 if (input_event_to_user(buffer + read, &event)) 587 return -EFAULT; 588 589 read += input_event_size(); 590 } 591 592 if (read) 593 break; 594 595 if (!(file->f_flags & O_NONBLOCK)) { 596 error = wait_event_interruptible(client->wait, 597 client->packet_head != client->tail || 598 !evdev->exist || client->revoked); 599 if (error) 600 return error; 601 } 602 } 603 604 return read; 605 } 606 607 /* No kernel lock - fine */ 608 static __poll_t evdev_poll(struct file *file, poll_table *wait) 609 { 610 struct evdev_client *client = file->private_data; 611 struct evdev *evdev = client->evdev; 612 __poll_t mask; 613 614 poll_wait(file, &client->wait, wait); 615 616 if (evdev->exist && !client->revoked) 617 mask = EPOLLOUT | EPOLLWRNORM; 618 else 619 mask = EPOLLHUP | EPOLLERR; 620 621 if (client->packet_head != client->tail) 622 mask |= EPOLLIN | EPOLLRDNORM; 623 624 return mask; 625 } 626 627 #ifdef CONFIG_COMPAT 628 629 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8) 630 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1) 631 632 #ifdef __BIG_ENDIAN 633 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 634 unsigned int maxlen, void __user *p, int compat) 635 { 636 int len, i; 637 638 if (compat) { 639 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t); 640 if (len > maxlen) 641 len = maxlen; 642 643 for (i = 0; i < len / sizeof(compat_long_t); i++) 644 if (copy_to_user((compat_long_t __user *) p + i, 645 (compat_long_t *) bits + 646 i + 1 - ((i % 2) << 1), 647 sizeof(compat_long_t))) 648 return -EFAULT; 649 } else { 650 len = BITS_TO_LONGS(maxbit) * sizeof(long); 651 if (len > maxlen) 652 len = maxlen; 653 654 if (copy_to_user(p, bits, len)) 655 return -EFAULT; 656 } 657 658 return len; 659 } 660 661 static int bits_from_user(unsigned long *bits, unsigned int maxbit, 662 unsigned int maxlen, const void __user *p, int compat) 663 { 664 int len, i; 665 666 if (compat) { 667 if (maxlen % sizeof(compat_long_t)) 668 return -EINVAL; 669 670 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t); 671 if (len > maxlen) 672 len = maxlen; 673 674 for (i = 0; i < len / sizeof(compat_long_t); i++) 675 if (copy_from_user((compat_long_t *) bits + 676 i + 1 - ((i % 2) << 1), 677 (compat_long_t __user *) p + i, 678 sizeof(compat_long_t))) 679 return -EFAULT; 680 if (i % 2) 681 *((compat_long_t *) bits + i - 1) = 0; 682 683 } else { 684 if (maxlen % sizeof(long)) 685 return -EINVAL; 686 687 len = BITS_TO_LONGS(maxbit) * sizeof(long); 688 if (len > maxlen) 689 len = maxlen; 690 691 if (copy_from_user(bits, p, len)) 692 return -EFAULT; 693 } 694 695 return len; 696 } 697 698 #else 699 700 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 701 unsigned int maxlen, void __user *p, int compat) 702 { 703 int len = compat ? 704 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) : 705 BITS_TO_LONGS(maxbit) * sizeof(long); 706 707 if (len > maxlen) 708 len = maxlen; 709 710 return copy_to_user(p, bits, len) ? -EFAULT : len; 711 } 712 713 static int bits_from_user(unsigned long *bits, unsigned int maxbit, 714 unsigned int maxlen, const void __user *p, int compat) 715 { 716 size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long); 717 int len; 718 719 if (maxlen % chunk_size) 720 return -EINVAL; 721 722 len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit); 723 len *= chunk_size; 724 if (len > maxlen) 725 len = maxlen; 726 727 return copy_from_user(bits, p, len) ? -EFAULT : len; 728 } 729 730 #endif /* __BIG_ENDIAN */ 731 732 #else 733 734 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 735 unsigned int maxlen, void __user *p, int compat) 736 { 737 int len = BITS_TO_LONGS(maxbit) * sizeof(long); 738 739 if (len > maxlen) 740 len = maxlen; 741 742 return copy_to_user(p, bits, len) ? -EFAULT : len; 743 } 744 745 static int bits_from_user(unsigned long *bits, unsigned int maxbit, 746 unsigned int maxlen, const void __user *p, int compat) 747 { 748 int len; 749 750 if (maxlen % sizeof(long)) 751 return -EINVAL; 752 753 len = BITS_TO_LONGS(maxbit) * sizeof(long); 754 if (len > maxlen) 755 len = maxlen; 756 757 return copy_from_user(bits, p, len) ? -EFAULT : len; 758 } 759 760 #endif /* CONFIG_COMPAT */ 761 762 static int str_to_user(const char *str, unsigned int maxlen, void __user *p) 763 { 764 int len; 765 766 if (!str) 767 return -ENOENT; 768 769 len = strlen(str) + 1; 770 if (len > maxlen) 771 len = maxlen; 772 773 return copy_to_user(p, str, len) ? -EFAULT : len; 774 } 775 776 static int handle_eviocgbit(struct input_dev *dev, 777 unsigned int type, unsigned int size, 778 void __user *p, int compat_mode) 779 { 780 unsigned long *bits; 781 int len; 782 783 switch (type) { 784 785 case 0: bits = dev->evbit; len = EV_MAX; break; 786 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break; 787 case EV_REL: bits = dev->relbit; len = REL_MAX; break; 788 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break; 789 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break; 790 case EV_LED: bits = dev->ledbit; len = LED_MAX; break; 791 case EV_SND: bits = dev->sndbit; len = SND_MAX; break; 792 case EV_FF: bits = dev->ffbit; len = FF_MAX; break; 793 case EV_SW: bits = dev->swbit; len = SW_MAX; break; 794 default: return -EINVAL; 795 } 796 797 return bits_to_user(bits, len, size, p, compat_mode); 798 } 799 800 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p) 801 { 802 struct input_keymap_entry ke = { 803 .len = sizeof(unsigned int), 804 .flags = 0, 805 }; 806 int __user *ip = (int __user *)p; 807 int error; 808 809 /* legacy case */ 810 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 811 return -EFAULT; 812 813 error = input_get_keycode(dev, &ke); 814 if (error) 815 return error; 816 817 if (put_user(ke.keycode, ip + 1)) 818 return -EFAULT; 819 820 return 0; 821 } 822 823 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p) 824 { 825 struct input_keymap_entry ke; 826 int error; 827 828 if (copy_from_user(&ke, p, sizeof(ke))) 829 return -EFAULT; 830 831 error = input_get_keycode(dev, &ke); 832 if (error) 833 return error; 834 835 if (copy_to_user(p, &ke, sizeof(ke))) 836 return -EFAULT; 837 838 return 0; 839 } 840 841 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p) 842 { 843 struct input_keymap_entry ke = { 844 .len = sizeof(unsigned int), 845 .flags = 0, 846 }; 847 int __user *ip = (int __user *)p; 848 849 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 850 return -EFAULT; 851 852 if (get_user(ke.keycode, ip + 1)) 853 return -EFAULT; 854 855 return input_set_keycode(dev, &ke); 856 } 857 858 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p) 859 { 860 struct input_keymap_entry ke; 861 862 if (copy_from_user(&ke, p, sizeof(ke))) 863 return -EFAULT; 864 865 if (ke.len > sizeof(ke.scancode)) 866 return -EINVAL; 867 868 return input_set_keycode(dev, &ke); 869 } 870 871 /* 872 * If we transfer state to the user, we should flush all pending events 873 * of the same type from the client's queue. Otherwise, they might end up 874 * with duplicate events, which can screw up client's state tracking. 875 * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED 876 * event so user-space will notice missing events. 877 * 878 * LOCKING: 879 * We need to take event_lock before buffer_lock to avoid dead-locks. But we 880 * need the even_lock only to guarantee consistent state. We can safely release 881 * it while flushing the queue. This allows input-core to handle filters while 882 * we flush the queue. 883 */ 884 static int evdev_handle_get_val(struct evdev_client *client, 885 struct input_dev *dev, unsigned int type, 886 unsigned long *bits, unsigned int maxbit, 887 unsigned int maxlen, void __user *p, 888 int compat) 889 { 890 int ret; 891 unsigned long *mem; 892 893 mem = bitmap_alloc(maxbit, GFP_KERNEL); 894 if (!mem) 895 return -ENOMEM; 896 897 spin_lock_irq(&dev->event_lock); 898 spin_lock(&client->buffer_lock); 899 900 bitmap_copy(mem, bits, maxbit); 901 902 spin_unlock(&dev->event_lock); 903 904 __evdev_flush_queue(client, type); 905 906 spin_unlock_irq(&client->buffer_lock); 907 908 ret = bits_to_user(mem, maxbit, maxlen, p, compat); 909 if (ret < 0) 910 evdev_queue_syn_dropped(client); 911 912 bitmap_free(mem); 913 914 return ret; 915 } 916 917 static int evdev_handle_mt_request(struct input_dev *dev, 918 unsigned int size, 919 int __user *ip) 920 { 921 const struct input_mt *mt = dev->mt; 922 unsigned int code; 923 int max_slots; 924 int i; 925 926 if (get_user(code, &ip[0])) 927 return -EFAULT; 928 if (!mt || !input_is_mt_value(code)) 929 return -EINVAL; 930 931 max_slots = (size - sizeof(__u32)) / sizeof(__s32); 932 for (i = 0; i < mt->num_slots && i < max_slots; i++) { 933 int value = input_mt_get_value(&mt->slots[i], code); 934 if (put_user(value, &ip[1 + i])) 935 return -EFAULT; 936 } 937 938 return 0; 939 } 940 941 static int evdev_revoke(struct evdev *evdev, struct evdev_client *client, 942 struct file *file) 943 { 944 client->revoked = true; 945 evdev_ungrab(evdev, client); 946 input_flush_device(&evdev->handle, file); 947 wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR); 948 949 return 0; 950 } 951 952 /* must be called with evdev-mutex held */ 953 static int evdev_set_mask(struct evdev_client *client, 954 unsigned int type, 955 const void __user *codes, 956 u32 codes_size, 957 int compat) 958 { 959 unsigned long flags, *mask, *oldmask; 960 size_t cnt; 961 int error; 962 963 /* we allow unknown types and 'codes_size > size' for forward-compat */ 964 cnt = evdev_get_mask_cnt(type); 965 if (!cnt) 966 return 0; 967 968 mask = bitmap_zalloc(cnt, GFP_KERNEL); 969 if (!mask) 970 return -ENOMEM; 971 972 error = bits_from_user(mask, cnt - 1, codes_size, codes, compat); 973 if (error < 0) { 974 bitmap_free(mask); 975 return error; 976 } 977 978 spin_lock_irqsave(&client->buffer_lock, flags); 979 oldmask = client->evmasks[type]; 980 client->evmasks[type] = mask; 981 spin_unlock_irqrestore(&client->buffer_lock, flags); 982 983 bitmap_free(oldmask); 984 985 return 0; 986 } 987 988 /* must be called with evdev-mutex held */ 989 static int evdev_get_mask(struct evdev_client *client, 990 unsigned int type, 991 void __user *codes, 992 u32 codes_size, 993 int compat) 994 { 995 unsigned long *mask; 996 size_t cnt, size, xfer_size; 997 int i; 998 int error; 999 1000 /* we allow unknown types and 'codes_size > size' for forward-compat */ 1001 cnt = evdev_get_mask_cnt(type); 1002 size = sizeof(unsigned long) * BITS_TO_LONGS(cnt); 1003 xfer_size = min_t(size_t, codes_size, size); 1004 1005 if (cnt > 0) { 1006 mask = client->evmasks[type]; 1007 if (mask) { 1008 error = bits_to_user(mask, cnt - 1, 1009 xfer_size, codes, compat); 1010 if (error < 0) 1011 return error; 1012 } else { 1013 /* fake mask with all bits set */ 1014 for (i = 0; i < xfer_size; i++) 1015 if (put_user(0xffU, (u8 __user *)codes + i)) 1016 return -EFAULT; 1017 } 1018 } 1019 1020 if (xfer_size < codes_size) 1021 if (clear_user(codes + xfer_size, codes_size - xfer_size)) 1022 return -EFAULT; 1023 1024 return 0; 1025 } 1026 1027 static long evdev_do_ioctl(struct file *file, unsigned int cmd, 1028 void __user *p, int compat_mode) 1029 { 1030 struct evdev_client *client = file->private_data; 1031 struct evdev *evdev = client->evdev; 1032 struct input_dev *dev = evdev->handle.dev; 1033 struct input_absinfo abs; 1034 struct input_mask mask; 1035 struct ff_effect effect; 1036 int __user *ip = (int __user *)p; 1037 unsigned int i, t, u, v; 1038 unsigned int size; 1039 int error; 1040 1041 /* First we check for fixed-length commands */ 1042 switch (cmd) { 1043 1044 case EVIOCGVERSION: 1045 return put_user(EV_VERSION, ip); 1046 1047 case EVIOCGID: 1048 if (copy_to_user(p, &dev->id, sizeof(struct input_id))) 1049 return -EFAULT; 1050 return 0; 1051 1052 case EVIOCGREP: 1053 if (!test_bit(EV_REP, dev->evbit)) 1054 return -ENOSYS; 1055 if (put_user(dev->rep[REP_DELAY], ip)) 1056 return -EFAULT; 1057 if (put_user(dev->rep[REP_PERIOD], ip + 1)) 1058 return -EFAULT; 1059 return 0; 1060 1061 case EVIOCSREP: 1062 if (!test_bit(EV_REP, dev->evbit)) 1063 return -ENOSYS; 1064 if (get_user(u, ip)) 1065 return -EFAULT; 1066 if (get_user(v, ip + 1)) 1067 return -EFAULT; 1068 1069 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u); 1070 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v); 1071 1072 return 0; 1073 1074 case EVIOCRMFF: 1075 return input_ff_erase(dev, (int)(unsigned long) p, file); 1076 1077 case EVIOCGEFFECTS: 1078 i = test_bit(EV_FF, dev->evbit) ? 1079 dev->ff->max_effects : 0; 1080 if (put_user(i, ip)) 1081 return -EFAULT; 1082 return 0; 1083 1084 case EVIOCGRAB: 1085 if (p) 1086 return evdev_grab(evdev, client); 1087 else 1088 return evdev_ungrab(evdev, client); 1089 1090 case EVIOCREVOKE: 1091 if (p) 1092 return -EINVAL; 1093 else 1094 return evdev_revoke(evdev, client, file); 1095 1096 case EVIOCGMASK: { 1097 void __user *codes_ptr; 1098 1099 if (copy_from_user(&mask, p, sizeof(mask))) 1100 return -EFAULT; 1101 1102 codes_ptr = (void __user *)(unsigned long)mask.codes_ptr; 1103 return evdev_get_mask(client, 1104 mask.type, codes_ptr, mask.codes_size, 1105 compat_mode); 1106 } 1107 1108 case EVIOCSMASK: { 1109 const void __user *codes_ptr; 1110 1111 if (copy_from_user(&mask, p, sizeof(mask))) 1112 return -EFAULT; 1113 1114 codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr; 1115 return evdev_set_mask(client, 1116 mask.type, codes_ptr, mask.codes_size, 1117 compat_mode); 1118 } 1119 1120 case EVIOCSCLOCKID: 1121 if (copy_from_user(&i, p, sizeof(unsigned int))) 1122 return -EFAULT; 1123 1124 return evdev_set_clk_type(client, i); 1125 1126 case EVIOCGKEYCODE: 1127 return evdev_handle_get_keycode(dev, p); 1128 1129 case EVIOCSKEYCODE: 1130 return evdev_handle_set_keycode(dev, p); 1131 1132 case EVIOCGKEYCODE_V2: 1133 return evdev_handle_get_keycode_v2(dev, p); 1134 1135 case EVIOCSKEYCODE_V2: 1136 return evdev_handle_set_keycode_v2(dev, p); 1137 } 1138 1139 size = _IOC_SIZE(cmd); 1140 1141 /* Now check variable-length commands */ 1142 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT)) 1143 switch (EVIOC_MASK_SIZE(cmd)) { 1144 1145 case EVIOCGPROP(0): 1146 return bits_to_user(dev->propbit, INPUT_PROP_MAX, 1147 size, p, compat_mode); 1148 1149 case EVIOCGMTSLOTS(0): 1150 return evdev_handle_mt_request(dev, size, ip); 1151 1152 case EVIOCGKEY(0): 1153 return evdev_handle_get_val(client, dev, EV_KEY, dev->key, 1154 KEY_MAX, size, p, compat_mode); 1155 1156 case EVIOCGLED(0): 1157 return evdev_handle_get_val(client, dev, EV_LED, dev->led, 1158 LED_MAX, size, p, compat_mode); 1159 1160 case EVIOCGSND(0): 1161 return evdev_handle_get_val(client, dev, EV_SND, dev->snd, 1162 SND_MAX, size, p, compat_mode); 1163 1164 case EVIOCGSW(0): 1165 return evdev_handle_get_val(client, dev, EV_SW, dev->sw, 1166 SW_MAX, size, p, compat_mode); 1167 1168 case EVIOCGNAME(0): 1169 return str_to_user(dev->name, size, p); 1170 1171 case EVIOCGPHYS(0): 1172 return str_to_user(dev->phys, size, p); 1173 1174 case EVIOCGUNIQ(0): 1175 return str_to_user(dev->uniq, size, p); 1176 1177 case EVIOC_MASK_SIZE(EVIOCSFF): 1178 if (input_ff_effect_from_user(p, size, &effect)) 1179 return -EFAULT; 1180 1181 error = input_ff_upload(dev, &effect, file); 1182 if (error) 1183 return error; 1184 1185 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id))) 1186 return -EFAULT; 1187 1188 return 0; 1189 } 1190 1191 /* Multi-number variable-length handlers */ 1192 if (_IOC_TYPE(cmd) != 'E') 1193 return -EINVAL; 1194 1195 if (_IOC_DIR(cmd) == _IOC_READ) { 1196 1197 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) 1198 return handle_eviocgbit(dev, 1199 _IOC_NR(cmd) & EV_MAX, size, 1200 p, compat_mode); 1201 1202 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) { 1203 1204 if (!dev->absinfo) 1205 return -EINVAL; 1206 1207 t = _IOC_NR(cmd) & ABS_MAX; 1208 abs = dev->absinfo[t]; 1209 1210 if (copy_to_user(p, &abs, min_t(size_t, 1211 size, sizeof(struct input_absinfo)))) 1212 return -EFAULT; 1213 1214 return 0; 1215 } 1216 } 1217 1218 if (_IOC_DIR(cmd) == _IOC_WRITE) { 1219 1220 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) { 1221 1222 if (!dev->absinfo) 1223 return -EINVAL; 1224 1225 t = _IOC_NR(cmd) & ABS_MAX; 1226 1227 if (copy_from_user(&abs, p, min_t(size_t, 1228 size, sizeof(struct input_absinfo)))) 1229 return -EFAULT; 1230 1231 if (size < sizeof(struct input_absinfo)) 1232 abs.resolution = 0; 1233 1234 /* We can't change number of reserved MT slots */ 1235 if (t == ABS_MT_SLOT) 1236 return -EINVAL; 1237 1238 /* 1239 * Take event lock to ensure that we are not 1240 * changing device parameters in the middle 1241 * of event. 1242 */ 1243 spin_lock_irq(&dev->event_lock); 1244 dev->absinfo[t] = abs; 1245 spin_unlock_irq(&dev->event_lock); 1246 1247 return 0; 1248 } 1249 } 1250 1251 return -EINVAL; 1252 } 1253 1254 static long evdev_ioctl_handler(struct file *file, unsigned int cmd, 1255 void __user *p, int compat_mode) 1256 { 1257 struct evdev_client *client = file->private_data; 1258 struct evdev *evdev = client->evdev; 1259 int retval; 1260 1261 retval = mutex_lock_interruptible(&evdev->mutex); 1262 if (retval) 1263 return retval; 1264 1265 if (!evdev->exist || client->revoked) { 1266 retval = -ENODEV; 1267 goto out; 1268 } 1269 1270 retval = evdev_do_ioctl(file, cmd, p, compat_mode); 1271 1272 out: 1273 mutex_unlock(&evdev->mutex); 1274 return retval; 1275 } 1276 1277 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 1278 { 1279 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0); 1280 } 1281 1282 #ifdef CONFIG_COMPAT 1283 static long evdev_ioctl_compat(struct file *file, 1284 unsigned int cmd, unsigned long arg) 1285 { 1286 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1); 1287 } 1288 #endif 1289 1290 static const struct file_operations evdev_fops = { 1291 .owner = THIS_MODULE, 1292 .read = evdev_read, 1293 .write = evdev_write, 1294 .poll = evdev_poll, 1295 .open = evdev_open, 1296 .release = evdev_release, 1297 .unlocked_ioctl = evdev_ioctl, 1298 #ifdef CONFIG_COMPAT 1299 .compat_ioctl = evdev_ioctl_compat, 1300 #endif 1301 .fasync = evdev_fasync, 1302 }; 1303 1304 /* 1305 * Mark device non-existent. This disables writes, ioctls and 1306 * prevents new users from opening the device. Already posted 1307 * blocking reads will stay, however new ones will fail. 1308 */ 1309 static void evdev_mark_dead(struct evdev *evdev) 1310 { 1311 mutex_lock(&evdev->mutex); 1312 evdev->exist = false; 1313 mutex_unlock(&evdev->mutex); 1314 } 1315 1316 static void evdev_cleanup(struct evdev *evdev) 1317 { 1318 struct input_handle *handle = &evdev->handle; 1319 1320 evdev_mark_dead(evdev); 1321 evdev_hangup(evdev); 1322 1323 /* evdev is marked dead so no one else accesses evdev->open */ 1324 if (evdev->open) { 1325 input_flush_device(handle, NULL); 1326 input_close_device(handle); 1327 } 1328 } 1329 1330 /* 1331 * Create new evdev device. Note that input core serializes calls 1332 * to connect and disconnect. 1333 */ 1334 static int evdev_connect(struct input_handler *handler, struct input_dev *dev, 1335 const struct input_device_id *id) 1336 { 1337 struct evdev *evdev; 1338 int minor; 1339 int dev_no; 1340 int error; 1341 1342 minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true); 1343 if (minor < 0) { 1344 error = minor; 1345 pr_err("failed to reserve new minor: %d\n", error); 1346 return error; 1347 } 1348 1349 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL); 1350 if (!evdev) { 1351 error = -ENOMEM; 1352 goto err_free_minor; 1353 } 1354 1355 INIT_LIST_HEAD(&evdev->client_list); 1356 spin_lock_init(&evdev->client_lock); 1357 mutex_init(&evdev->mutex); 1358 evdev->exist = true; 1359 1360 dev_no = minor; 1361 /* Normalize device number if it falls into legacy range */ 1362 if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS) 1363 dev_no -= EVDEV_MINOR_BASE; 1364 dev_set_name(&evdev->dev, "event%d", dev_no); 1365 1366 evdev->handle.dev = input_get_device(dev); 1367 evdev->handle.name = dev_name(&evdev->dev); 1368 evdev->handle.handler = handler; 1369 evdev->handle.private = evdev; 1370 1371 evdev->dev.devt = MKDEV(INPUT_MAJOR, minor); 1372 evdev->dev.class = &input_class; 1373 evdev->dev.parent = &dev->dev; 1374 evdev->dev.release = evdev_free; 1375 device_initialize(&evdev->dev); 1376 1377 error = input_register_handle(&evdev->handle); 1378 if (error) 1379 goto err_free_evdev; 1380 1381 cdev_init(&evdev->cdev, &evdev_fops); 1382 1383 error = cdev_device_add(&evdev->cdev, &evdev->dev); 1384 if (error) 1385 goto err_cleanup_evdev; 1386 1387 return 0; 1388 1389 err_cleanup_evdev: 1390 evdev_cleanup(evdev); 1391 input_unregister_handle(&evdev->handle); 1392 err_free_evdev: 1393 put_device(&evdev->dev); 1394 err_free_minor: 1395 input_free_minor(minor); 1396 return error; 1397 } 1398 1399 static void evdev_disconnect(struct input_handle *handle) 1400 { 1401 struct evdev *evdev = handle->private; 1402 1403 cdev_device_del(&evdev->cdev, &evdev->dev); 1404 evdev_cleanup(evdev); 1405 input_free_minor(MINOR(evdev->dev.devt)); 1406 input_unregister_handle(handle); 1407 put_device(&evdev->dev); 1408 } 1409 1410 static const struct input_device_id evdev_ids[] = { 1411 { .driver_info = 1 }, /* Matches all devices */ 1412 { }, /* Terminating zero entry */ 1413 }; 1414 1415 MODULE_DEVICE_TABLE(input, evdev_ids); 1416 1417 static struct input_handler evdev_handler = { 1418 .events = evdev_events, 1419 .connect = evdev_connect, 1420 .disconnect = evdev_disconnect, 1421 .legacy_minors = true, 1422 .minor = EVDEV_MINOR_BASE, 1423 .name = "evdev", 1424 .id_table = evdev_ids, 1425 }; 1426 1427 static int __init evdev_init(void) 1428 { 1429 return input_register_handler(&evdev_handler); 1430 } 1431 1432 static void __exit evdev_exit(void) 1433 { 1434 input_unregister_handler(&evdev_handler); 1435 } 1436 1437 module_init(evdev_init); 1438 module_exit(evdev_exit); 1439 1440 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); 1441 MODULE_DESCRIPTION("Input driver event char devices"); 1442 MODULE_LICENSE("GPL"); 1443