1 /* 2 * Event char devices, giving access to raw input device events. 3 * 4 * Copyright (c) 1999-2002 Vojtech Pavlik 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 as published by 8 * the Free Software Foundation. 9 */ 10 11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 12 13 #define EVDEV_MINOR_BASE 64 14 #define EVDEV_MINORS 32 15 #define EVDEV_MIN_BUFFER_SIZE 64U 16 #define EVDEV_BUF_PACKETS 8 17 18 #include <linux/poll.h> 19 #include <linux/sched.h> 20 #include <linux/slab.h> 21 #include <linux/module.h> 22 #include <linux/init.h> 23 #include <linux/input.h> 24 #include <linux/major.h> 25 #include <linux/device.h> 26 #include "input-compat.h" 27 28 struct evdev { 29 int open; 30 int minor; 31 struct input_handle handle; 32 wait_queue_head_t wait; 33 struct evdev_client __rcu *grab; 34 struct list_head client_list; 35 spinlock_t client_lock; /* protects client_list */ 36 struct mutex mutex; 37 struct device dev; 38 bool exist; 39 }; 40 41 struct evdev_client { 42 unsigned int head; 43 unsigned int tail; 44 unsigned int packet_head; /* [future] position of the first element of next packet */ 45 spinlock_t buffer_lock; /* protects access to buffer, head and tail */ 46 struct fasync_struct *fasync; 47 struct evdev *evdev; 48 struct list_head node; 49 unsigned int bufsize; 50 struct input_event buffer[]; 51 }; 52 53 static struct evdev *evdev_table[EVDEV_MINORS]; 54 static DEFINE_MUTEX(evdev_table_mutex); 55 56 static void evdev_pass_event(struct evdev_client *client, 57 struct input_event *event) 58 { 59 /* Interrupts are disabled, just acquire the lock. */ 60 spin_lock(&client->buffer_lock); 61 62 client->buffer[client->head++] = *event; 63 client->head &= client->bufsize - 1; 64 65 if (unlikely(client->head == client->tail)) { 66 /* 67 * This effectively "drops" all unconsumed events, leaving 68 * EV_SYN/SYN_DROPPED plus the newest event in the queue. 69 */ 70 client->tail = (client->head - 2) & (client->bufsize - 1); 71 72 client->buffer[client->tail].time = event->time; 73 client->buffer[client->tail].type = EV_SYN; 74 client->buffer[client->tail].code = SYN_DROPPED; 75 client->buffer[client->tail].value = 0; 76 77 client->packet_head = client->tail; 78 } 79 80 if (event->type == EV_SYN && event->code == SYN_REPORT) { 81 client->packet_head = client->head; 82 kill_fasync(&client->fasync, SIGIO, POLL_IN); 83 } 84 85 spin_unlock(&client->buffer_lock); 86 } 87 88 /* 89 * Pass incoming event to all connected clients. 90 */ 91 static void evdev_event(struct input_handle *handle, 92 unsigned int type, unsigned int code, int value) 93 { 94 struct evdev *evdev = handle->private; 95 struct evdev_client *client; 96 struct input_event event; 97 98 do_gettimeofday(&event.time); 99 event.type = type; 100 event.code = code; 101 event.value = value; 102 103 rcu_read_lock(); 104 105 client = rcu_dereference(evdev->grab); 106 if (client) 107 evdev_pass_event(client, &event); 108 else 109 list_for_each_entry_rcu(client, &evdev->client_list, node) 110 evdev_pass_event(client, &event); 111 112 rcu_read_unlock(); 113 114 wake_up_interruptible(&evdev->wait); 115 } 116 117 static int evdev_fasync(int fd, struct file *file, int on) 118 { 119 struct evdev_client *client = file->private_data; 120 121 return fasync_helper(fd, file, on, &client->fasync); 122 } 123 124 static int evdev_flush(struct file *file, fl_owner_t id) 125 { 126 struct evdev_client *client = file->private_data; 127 struct evdev *evdev = client->evdev; 128 int retval; 129 130 retval = mutex_lock_interruptible(&evdev->mutex); 131 if (retval) 132 return retval; 133 134 if (!evdev->exist) 135 retval = -ENODEV; 136 else 137 retval = input_flush_device(&evdev->handle, file); 138 139 mutex_unlock(&evdev->mutex); 140 return retval; 141 } 142 143 static void evdev_free(struct device *dev) 144 { 145 struct evdev *evdev = container_of(dev, struct evdev, dev); 146 147 input_put_device(evdev->handle.dev); 148 kfree(evdev); 149 } 150 151 /* 152 * Grabs an event device (along with underlying input device). 153 * This function is called with evdev->mutex taken. 154 */ 155 static int evdev_grab(struct evdev *evdev, struct evdev_client *client) 156 { 157 int error; 158 159 if (evdev->grab) 160 return -EBUSY; 161 162 error = input_grab_device(&evdev->handle); 163 if (error) 164 return error; 165 166 rcu_assign_pointer(evdev->grab, client); 167 168 return 0; 169 } 170 171 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client) 172 { 173 if (evdev->grab != client) 174 return -EINVAL; 175 176 rcu_assign_pointer(evdev->grab, NULL); 177 synchronize_rcu(); 178 input_release_device(&evdev->handle); 179 180 return 0; 181 } 182 183 static void evdev_attach_client(struct evdev *evdev, 184 struct evdev_client *client) 185 { 186 spin_lock(&evdev->client_lock); 187 list_add_tail_rcu(&client->node, &evdev->client_list); 188 spin_unlock(&evdev->client_lock); 189 } 190 191 static void evdev_detach_client(struct evdev *evdev, 192 struct evdev_client *client) 193 { 194 spin_lock(&evdev->client_lock); 195 list_del_rcu(&client->node); 196 spin_unlock(&evdev->client_lock); 197 synchronize_rcu(); 198 } 199 200 static int evdev_open_device(struct evdev *evdev) 201 { 202 int retval; 203 204 retval = mutex_lock_interruptible(&evdev->mutex); 205 if (retval) 206 return retval; 207 208 if (!evdev->exist) 209 retval = -ENODEV; 210 else if (!evdev->open++) { 211 retval = input_open_device(&evdev->handle); 212 if (retval) 213 evdev->open--; 214 } 215 216 mutex_unlock(&evdev->mutex); 217 return retval; 218 } 219 220 static void evdev_close_device(struct evdev *evdev) 221 { 222 mutex_lock(&evdev->mutex); 223 224 if (evdev->exist && !--evdev->open) 225 input_close_device(&evdev->handle); 226 227 mutex_unlock(&evdev->mutex); 228 } 229 230 /* 231 * Wake up users waiting for IO so they can disconnect from 232 * dead device. 233 */ 234 static void evdev_hangup(struct evdev *evdev) 235 { 236 struct evdev_client *client; 237 238 spin_lock(&evdev->client_lock); 239 list_for_each_entry(client, &evdev->client_list, node) 240 kill_fasync(&client->fasync, SIGIO, POLL_HUP); 241 spin_unlock(&evdev->client_lock); 242 243 wake_up_interruptible(&evdev->wait); 244 } 245 246 static int evdev_release(struct inode *inode, struct file *file) 247 { 248 struct evdev_client *client = file->private_data; 249 struct evdev *evdev = client->evdev; 250 251 mutex_lock(&evdev->mutex); 252 if (evdev->grab == client) 253 evdev_ungrab(evdev, client); 254 mutex_unlock(&evdev->mutex); 255 256 evdev_detach_client(evdev, client); 257 kfree(client); 258 259 evdev_close_device(evdev); 260 put_device(&evdev->dev); 261 262 return 0; 263 } 264 265 static unsigned int evdev_compute_buffer_size(struct input_dev *dev) 266 { 267 unsigned int n_events = 268 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS, 269 EVDEV_MIN_BUFFER_SIZE); 270 271 return roundup_pow_of_two(n_events); 272 } 273 274 static int evdev_open(struct inode *inode, struct file *file) 275 { 276 struct evdev *evdev; 277 struct evdev_client *client; 278 int i = iminor(inode) - EVDEV_MINOR_BASE; 279 unsigned int bufsize; 280 int error; 281 282 if (i >= EVDEV_MINORS) 283 return -ENODEV; 284 285 error = mutex_lock_interruptible(&evdev_table_mutex); 286 if (error) 287 return error; 288 evdev = evdev_table[i]; 289 if (evdev) 290 get_device(&evdev->dev); 291 mutex_unlock(&evdev_table_mutex); 292 293 if (!evdev) 294 return -ENODEV; 295 296 bufsize = evdev_compute_buffer_size(evdev->handle.dev); 297 298 client = kzalloc(sizeof(struct evdev_client) + 299 bufsize * sizeof(struct input_event), 300 GFP_KERNEL); 301 if (!client) { 302 error = -ENOMEM; 303 goto err_put_evdev; 304 } 305 306 client->bufsize = bufsize; 307 spin_lock_init(&client->buffer_lock); 308 client->evdev = evdev; 309 evdev_attach_client(evdev, client); 310 311 error = evdev_open_device(evdev); 312 if (error) 313 goto err_free_client; 314 315 file->private_data = client; 316 nonseekable_open(inode, file); 317 318 return 0; 319 320 err_free_client: 321 evdev_detach_client(evdev, client); 322 kfree(client); 323 err_put_evdev: 324 put_device(&evdev->dev); 325 return error; 326 } 327 328 static ssize_t evdev_write(struct file *file, const char __user *buffer, 329 size_t count, loff_t *ppos) 330 { 331 struct evdev_client *client = file->private_data; 332 struct evdev *evdev = client->evdev; 333 struct input_event event; 334 int retval; 335 336 if (count < input_event_size()) 337 return -EINVAL; 338 339 retval = mutex_lock_interruptible(&evdev->mutex); 340 if (retval) 341 return retval; 342 343 if (!evdev->exist) { 344 retval = -ENODEV; 345 goto out; 346 } 347 348 do { 349 if (input_event_from_user(buffer + retval, &event)) { 350 retval = -EFAULT; 351 goto out; 352 } 353 retval += input_event_size(); 354 355 input_inject_event(&evdev->handle, 356 event.type, event.code, event.value); 357 } while (retval + input_event_size() <= count); 358 359 out: 360 mutex_unlock(&evdev->mutex); 361 return retval; 362 } 363 364 static int evdev_fetch_next_event(struct evdev_client *client, 365 struct input_event *event) 366 { 367 int have_event; 368 369 spin_lock_irq(&client->buffer_lock); 370 371 have_event = client->head != client->tail; 372 if (have_event) { 373 *event = client->buffer[client->tail++]; 374 client->tail &= client->bufsize - 1; 375 } 376 377 spin_unlock_irq(&client->buffer_lock); 378 379 return have_event; 380 } 381 382 static ssize_t evdev_read(struct file *file, char __user *buffer, 383 size_t count, loff_t *ppos) 384 { 385 struct evdev_client *client = file->private_data; 386 struct evdev *evdev = client->evdev; 387 struct input_event event; 388 int retval; 389 390 if (count < input_event_size()) 391 return -EINVAL; 392 393 if (client->packet_head == client->tail && evdev->exist && 394 (file->f_flags & O_NONBLOCK)) 395 return -EAGAIN; 396 397 retval = wait_event_interruptible(evdev->wait, 398 client->packet_head != client->tail || !evdev->exist); 399 if (retval) 400 return retval; 401 402 if (!evdev->exist) 403 return -ENODEV; 404 405 while (retval + input_event_size() <= count && 406 evdev_fetch_next_event(client, &event)) { 407 408 if (input_event_to_user(buffer + retval, &event)) 409 return -EFAULT; 410 411 retval += input_event_size(); 412 } 413 414 return retval; 415 } 416 417 /* No kernel lock - fine */ 418 static unsigned int evdev_poll(struct file *file, poll_table *wait) 419 { 420 struct evdev_client *client = file->private_data; 421 struct evdev *evdev = client->evdev; 422 unsigned int mask; 423 424 poll_wait(file, &evdev->wait, wait); 425 426 mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR; 427 if (client->packet_head != client->tail) 428 mask |= POLLIN | POLLRDNORM; 429 430 return mask; 431 } 432 433 #ifdef CONFIG_COMPAT 434 435 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8) 436 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1) 437 438 #ifdef __BIG_ENDIAN 439 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 440 unsigned int maxlen, void __user *p, int compat) 441 { 442 int len, i; 443 444 if (compat) { 445 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t); 446 if (len > maxlen) 447 len = maxlen; 448 449 for (i = 0; i < len / sizeof(compat_long_t); i++) 450 if (copy_to_user((compat_long_t __user *) p + i, 451 (compat_long_t *) bits + 452 i + 1 - ((i % 2) << 1), 453 sizeof(compat_long_t))) 454 return -EFAULT; 455 } else { 456 len = BITS_TO_LONGS(maxbit) * sizeof(long); 457 if (len > maxlen) 458 len = maxlen; 459 460 if (copy_to_user(p, bits, len)) 461 return -EFAULT; 462 } 463 464 return len; 465 } 466 #else 467 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 468 unsigned int maxlen, void __user *p, int compat) 469 { 470 int len = compat ? 471 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) : 472 BITS_TO_LONGS(maxbit) * sizeof(long); 473 474 if (len > maxlen) 475 len = maxlen; 476 477 return copy_to_user(p, bits, len) ? -EFAULT : len; 478 } 479 #endif /* __BIG_ENDIAN */ 480 481 #else 482 483 static int bits_to_user(unsigned long *bits, unsigned int maxbit, 484 unsigned int maxlen, void __user *p, int compat) 485 { 486 int len = BITS_TO_LONGS(maxbit) * sizeof(long); 487 488 if (len > maxlen) 489 len = maxlen; 490 491 return copy_to_user(p, bits, len) ? -EFAULT : len; 492 } 493 494 #endif /* CONFIG_COMPAT */ 495 496 static int str_to_user(const char *str, unsigned int maxlen, void __user *p) 497 { 498 int len; 499 500 if (!str) 501 return -ENOENT; 502 503 len = strlen(str) + 1; 504 if (len > maxlen) 505 len = maxlen; 506 507 return copy_to_user(p, str, len) ? -EFAULT : len; 508 } 509 510 #define OLD_KEY_MAX 0x1ff 511 static int handle_eviocgbit(struct input_dev *dev, 512 unsigned int type, unsigned int size, 513 void __user *p, int compat_mode) 514 { 515 static unsigned long keymax_warn_time; 516 unsigned long *bits; 517 int len; 518 519 switch (type) { 520 521 case 0: bits = dev->evbit; len = EV_MAX; break; 522 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break; 523 case EV_REL: bits = dev->relbit; len = REL_MAX; break; 524 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break; 525 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break; 526 case EV_LED: bits = dev->ledbit; len = LED_MAX; break; 527 case EV_SND: bits = dev->sndbit; len = SND_MAX; break; 528 case EV_FF: bits = dev->ffbit; len = FF_MAX; break; 529 case EV_SW: bits = dev->swbit; len = SW_MAX; break; 530 default: return -EINVAL; 531 } 532 533 /* 534 * Work around bugs in userspace programs that like to do 535 * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len' 536 * should be in bytes, not in bits. 537 */ 538 if (type == EV_KEY && size == OLD_KEY_MAX) { 539 len = OLD_KEY_MAX; 540 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000)) 541 pr_warning("(EVIOCGBIT): Suspicious buffer size %u, " 542 "limiting output to %zu bytes. See " 543 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n", 544 OLD_KEY_MAX, 545 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long)); 546 } 547 548 return bits_to_user(bits, len, size, p, compat_mode); 549 } 550 #undef OLD_KEY_MAX 551 552 static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p) 553 { 554 struct input_keymap_entry ke = { 555 .len = sizeof(unsigned int), 556 .flags = 0, 557 }; 558 int __user *ip = (int __user *)p; 559 int error; 560 561 /* legacy case */ 562 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 563 return -EFAULT; 564 565 error = input_get_keycode(dev, &ke); 566 if (error) 567 return error; 568 569 if (put_user(ke.keycode, ip + 1)) 570 return -EFAULT; 571 572 return 0; 573 } 574 575 static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p) 576 { 577 struct input_keymap_entry ke; 578 int error; 579 580 if (copy_from_user(&ke, p, sizeof(ke))) 581 return -EFAULT; 582 583 error = input_get_keycode(dev, &ke); 584 if (error) 585 return error; 586 587 if (copy_to_user(p, &ke, sizeof(ke))) 588 return -EFAULT; 589 590 return 0; 591 } 592 593 static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p) 594 { 595 struct input_keymap_entry ke = { 596 .len = sizeof(unsigned int), 597 .flags = 0, 598 }; 599 int __user *ip = (int __user *)p; 600 601 if (copy_from_user(ke.scancode, p, sizeof(unsigned int))) 602 return -EFAULT; 603 604 if (get_user(ke.keycode, ip + 1)) 605 return -EFAULT; 606 607 return input_set_keycode(dev, &ke); 608 } 609 610 static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p) 611 { 612 struct input_keymap_entry ke; 613 614 if (copy_from_user(&ke, p, sizeof(ke))) 615 return -EFAULT; 616 617 if (ke.len > sizeof(ke.scancode)) 618 return -EINVAL; 619 620 return input_set_keycode(dev, &ke); 621 } 622 623 static long evdev_do_ioctl(struct file *file, unsigned int cmd, 624 void __user *p, int compat_mode) 625 { 626 struct evdev_client *client = file->private_data; 627 struct evdev *evdev = client->evdev; 628 struct input_dev *dev = evdev->handle.dev; 629 struct input_absinfo abs; 630 struct ff_effect effect; 631 int __user *ip = (int __user *)p; 632 unsigned int i, t, u, v; 633 unsigned int size; 634 int error; 635 636 /* First we check for fixed-length commands */ 637 switch (cmd) { 638 639 case EVIOCGVERSION: 640 return put_user(EV_VERSION, ip); 641 642 case EVIOCGID: 643 if (copy_to_user(p, &dev->id, sizeof(struct input_id))) 644 return -EFAULT; 645 return 0; 646 647 case EVIOCGREP: 648 if (!test_bit(EV_REP, dev->evbit)) 649 return -ENOSYS; 650 if (put_user(dev->rep[REP_DELAY], ip)) 651 return -EFAULT; 652 if (put_user(dev->rep[REP_PERIOD], ip + 1)) 653 return -EFAULT; 654 return 0; 655 656 case EVIOCSREP: 657 if (!test_bit(EV_REP, dev->evbit)) 658 return -ENOSYS; 659 if (get_user(u, ip)) 660 return -EFAULT; 661 if (get_user(v, ip + 1)) 662 return -EFAULT; 663 664 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u); 665 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v); 666 667 return 0; 668 669 case EVIOCRMFF: 670 return input_ff_erase(dev, (int)(unsigned long) p, file); 671 672 case EVIOCGEFFECTS: 673 i = test_bit(EV_FF, dev->evbit) ? 674 dev->ff->max_effects : 0; 675 if (put_user(i, ip)) 676 return -EFAULT; 677 return 0; 678 679 case EVIOCGRAB: 680 if (p) 681 return evdev_grab(evdev, client); 682 else 683 return evdev_ungrab(evdev, client); 684 685 case EVIOCGKEYCODE: 686 return evdev_handle_get_keycode(dev, p); 687 688 case EVIOCSKEYCODE: 689 return evdev_handle_set_keycode(dev, p); 690 691 case EVIOCGKEYCODE_V2: 692 return evdev_handle_get_keycode_v2(dev, p); 693 694 case EVIOCSKEYCODE_V2: 695 return evdev_handle_set_keycode_v2(dev, p); 696 } 697 698 size = _IOC_SIZE(cmd); 699 700 /* Now check variable-length commands */ 701 #define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT)) 702 switch (EVIOC_MASK_SIZE(cmd)) { 703 704 case EVIOCGPROP(0): 705 return bits_to_user(dev->propbit, INPUT_PROP_MAX, 706 size, p, compat_mode); 707 708 case EVIOCGKEY(0): 709 return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode); 710 711 case EVIOCGLED(0): 712 return bits_to_user(dev->led, LED_MAX, size, p, compat_mode); 713 714 case EVIOCGSND(0): 715 return bits_to_user(dev->snd, SND_MAX, size, p, compat_mode); 716 717 case EVIOCGSW(0): 718 return bits_to_user(dev->sw, SW_MAX, size, p, compat_mode); 719 720 case EVIOCGNAME(0): 721 return str_to_user(dev->name, size, p); 722 723 case EVIOCGPHYS(0): 724 return str_to_user(dev->phys, size, p); 725 726 case EVIOCGUNIQ(0): 727 return str_to_user(dev->uniq, size, p); 728 729 case EVIOC_MASK_SIZE(EVIOCSFF): 730 if (input_ff_effect_from_user(p, size, &effect)) 731 return -EFAULT; 732 733 error = input_ff_upload(dev, &effect, file); 734 735 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id))) 736 return -EFAULT; 737 738 return error; 739 } 740 741 /* Multi-number variable-length handlers */ 742 if (_IOC_TYPE(cmd) != 'E') 743 return -EINVAL; 744 745 if (_IOC_DIR(cmd) == _IOC_READ) { 746 747 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) 748 return handle_eviocgbit(dev, 749 _IOC_NR(cmd) & EV_MAX, size, 750 p, compat_mode); 751 752 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) { 753 754 if (!dev->absinfo) 755 return -EINVAL; 756 757 t = _IOC_NR(cmd) & ABS_MAX; 758 abs = dev->absinfo[t]; 759 760 if (copy_to_user(p, &abs, min_t(size_t, 761 size, sizeof(struct input_absinfo)))) 762 return -EFAULT; 763 764 return 0; 765 } 766 } 767 768 if (_IOC_DIR(cmd) == _IOC_WRITE) { 769 770 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) { 771 772 if (!dev->absinfo) 773 return -EINVAL; 774 775 t = _IOC_NR(cmd) & ABS_MAX; 776 777 if (copy_from_user(&abs, p, min_t(size_t, 778 size, sizeof(struct input_absinfo)))) 779 return -EFAULT; 780 781 if (size < sizeof(struct input_absinfo)) 782 abs.resolution = 0; 783 784 /* We can't change number of reserved MT slots */ 785 if (t == ABS_MT_SLOT) 786 return -EINVAL; 787 788 /* 789 * Take event lock to ensure that we are not 790 * changing device parameters in the middle 791 * of event. 792 */ 793 spin_lock_irq(&dev->event_lock); 794 dev->absinfo[t] = abs; 795 spin_unlock_irq(&dev->event_lock); 796 797 return 0; 798 } 799 } 800 801 return -EINVAL; 802 } 803 804 static long evdev_ioctl_handler(struct file *file, unsigned int cmd, 805 void __user *p, int compat_mode) 806 { 807 struct evdev_client *client = file->private_data; 808 struct evdev *evdev = client->evdev; 809 int retval; 810 811 retval = mutex_lock_interruptible(&evdev->mutex); 812 if (retval) 813 return retval; 814 815 if (!evdev->exist) { 816 retval = -ENODEV; 817 goto out; 818 } 819 820 retval = evdev_do_ioctl(file, cmd, p, compat_mode); 821 822 out: 823 mutex_unlock(&evdev->mutex); 824 return retval; 825 } 826 827 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 828 { 829 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0); 830 } 831 832 #ifdef CONFIG_COMPAT 833 static long evdev_ioctl_compat(struct file *file, 834 unsigned int cmd, unsigned long arg) 835 { 836 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1); 837 } 838 #endif 839 840 static const struct file_operations evdev_fops = { 841 .owner = THIS_MODULE, 842 .read = evdev_read, 843 .write = evdev_write, 844 .poll = evdev_poll, 845 .open = evdev_open, 846 .release = evdev_release, 847 .unlocked_ioctl = evdev_ioctl, 848 #ifdef CONFIG_COMPAT 849 .compat_ioctl = evdev_ioctl_compat, 850 #endif 851 .fasync = evdev_fasync, 852 .flush = evdev_flush, 853 .llseek = no_llseek, 854 }; 855 856 static int evdev_install_chrdev(struct evdev *evdev) 857 { 858 /* 859 * No need to do any locking here as calls to connect and 860 * disconnect are serialized by the input core 861 */ 862 evdev_table[evdev->minor] = evdev; 863 return 0; 864 } 865 866 static void evdev_remove_chrdev(struct evdev *evdev) 867 { 868 /* 869 * Lock evdev table to prevent race with evdev_open() 870 */ 871 mutex_lock(&evdev_table_mutex); 872 evdev_table[evdev->minor] = NULL; 873 mutex_unlock(&evdev_table_mutex); 874 } 875 876 /* 877 * Mark device non-existent. This disables writes, ioctls and 878 * prevents new users from opening the device. Already posted 879 * blocking reads will stay, however new ones will fail. 880 */ 881 static void evdev_mark_dead(struct evdev *evdev) 882 { 883 mutex_lock(&evdev->mutex); 884 evdev->exist = false; 885 mutex_unlock(&evdev->mutex); 886 } 887 888 static void evdev_cleanup(struct evdev *evdev) 889 { 890 struct input_handle *handle = &evdev->handle; 891 892 evdev_mark_dead(evdev); 893 evdev_hangup(evdev); 894 evdev_remove_chrdev(evdev); 895 896 /* evdev is marked dead so no one else accesses evdev->open */ 897 if (evdev->open) { 898 input_flush_device(handle, NULL); 899 input_close_device(handle); 900 } 901 } 902 903 /* 904 * Create new evdev device. Note that input core serializes calls 905 * to connect and disconnect so we don't need to lock evdev_table here. 906 */ 907 static int evdev_connect(struct input_handler *handler, struct input_dev *dev, 908 const struct input_device_id *id) 909 { 910 struct evdev *evdev; 911 int minor; 912 int error; 913 914 for (minor = 0; minor < EVDEV_MINORS; minor++) 915 if (!evdev_table[minor]) 916 break; 917 918 if (minor == EVDEV_MINORS) { 919 pr_err("no more free evdev devices\n"); 920 return -ENFILE; 921 } 922 923 evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL); 924 if (!evdev) 925 return -ENOMEM; 926 927 INIT_LIST_HEAD(&evdev->client_list); 928 spin_lock_init(&evdev->client_lock); 929 mutex_init(&evdev->mutex); 930 init_waitqueue_head(&evdev->wait); 931 932 dev_set_name(&evdev->dev, "event%d", minor); 933 evdev->exist = true; 934 evdev->minor = minor; 935 936 evdev->handle.dev = input_get_device(dev); 937 evdev->handle.name = dev_name(&evdev->dev); 938 evdev->handle.handler = handler; 939 evdev->handle.private = evdev; 940 941 evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor); 942 evdev->dev.class = &input_class; 943 evdev->dev.parent = &dev->dev; 944 evdev->dev.release = evdev_free; 945 device_initialize(&evdev->dev); 946 947 error = input_register_handle(&evdev->handle); 948 if (error) 949 goto err_free_evdev; 950 951 error = evdev_install_chrdev(evdev); 952 if (error) 953 goto err_unregister_handle; 954 955 error = device_add(&evdev->dev); 956 if (error) 957 goto err_cleanup_evdev; 958 959 return 0; 960 961 err_cleanup_evdev: 962 evdev_cleanup(evdev); 963 err_unregister_handle: 964 input_unregister_handle(&evdev->handle); 965 err_free_evdev: 966 put_device(&evdev->dev); 967 return error; 968 } 969 970 static void evdev_disconnect(struct input_handle *handle) 971 { 972 struct evdev *evdev = handle->private; 973 974 device_del(&evdev->dev); 975 evdev_cleanup(evdev); 976 input_unregister_handle(handle); 977 put_device(&evdev->dev); 978 } 979 980 static const struct input_device_id evdev_ids[] = { 981 { .driver_info = 1 }, /* Matches all devices */ 982 { }, /* Terminating zero entry */ 983 }; 984 985 MODULE_DEVICE_TABLE(input, evdev_ids); 986 987 static struct input_handler evdev_handler = { 988 .event = evdev_event, 989 .connect = evdev_connect, 990 .disconnect = evdev_disconnect, 991 .fops = &evdev_fops, 992 .minor = EVDEV_MINOR_BASE, 993 .name = "evdev", 994 .id_table = evdev_ids, 995 }; 996 997 static int __init evdev_init(void) 998 { 999 return input_register_handler(&evdev_handler); 1000 } 1001 1002 static void __exit evdev_exit(void) 1003 { 1004 input_unregister_handler(&evdev_handler); 1005 } 1006 1007 module_init(evdev_init); 1008 module_exit(evdev_exit); 1009 1010 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); 1011 MODULE_DESCRIPTION("Input driver event char devices"); 1012 MODULE_LICENSE("GPL"); 1013