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