1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * HID raw devices, giving access to raw HID events. 4 * 5 * In comparison to hiddev, this device does not process the 6 * hid events at all (no parsing, no lookups). This lets applications 7 * to work on raw hid events as they want to, and avoids a need to 8 * use a transport-specific userspace libhid/libusb libraries. 9 * 10 * Copyright (c) 2007-2014 Jiri Kosina 11 */ 12 13 14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 15 16 #include <linux/fs.h> 17 #include <linux/module.h> 18 #include <linux/errno.h> 19 #include <linux/kernel.h> 20 #include <linux/init.h> 21 #include <linux/cdev.h> 22 #include <linux/poll.h> 23 #include <linux/device.h> 24 #include <linux/major.h> 25 #include <linux/slab.h> 26 #include <linux/hid.h> 27 #include <linux/mutex.h> 28 #include <linux/sched/signal.h> 29 #include <linux/string.h> 30 31 #include <linux/hidraw.h> 32 33 static int hidraw_major; 34 static struct cdev hidraw_cdev; 35 static const struct class hidraw_class = { 36 .name = "hidraw", 37 }; 38 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES]; 39 static DECLARE_RWSEM(minors_rwsem); 40 41 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos) 42 { 43 struct hidraw_list *list = file->private_data; 44 int ret = 0, len; 45 DECLARE_WAITQUEUE(wait, current); 46 47 mutex_lock(&list->read_mutex); 48 49 while (ret == 0) { 50 if (list->head == list->tail) { 51 add_wait_queue(&list->hidraw->wait, &wait); 52 set_current_state(TASK_INTERRUPTIBLE); 53 54 while (list->head == list->tail) { 55 if (signal_pending(current)) { 56 ret = -ERESTARTSYS; 57 break; 58 } 59 if (!list->hidraw->exist) { 60 ret = -EIO; 61 break; 62 } 63 if (file->f_flags & O_NONBLOCK) { 64 ret = -EAGAIN; 65 break; 66 } 67 68 /* allow O_NONBLOCK to work well from other threads */ 69 mutex_unlock(&list->read_mutex); 70 schedule(); 71 mutex_lock(&list->read_mutex); 72 set_current_state(TASK_INTERRUPTIBLE); 73 } 74 75 set_current_state(TASK_RUNNING); 76 remove_wait_queue(&list->hidraw->wait, &wait); 77 } 78 79 if (ret) 80 goto out; 81 82 len = list->buffer[list->tail].len > count ? 83 count : list->buffer[list->tail].len; 84 85 if (list->buffer[list->tail].value) { 86 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) { 87 ret = -EFAULT; 88 goto out; 89 } 90 ret = len; 91 } 92 93 kfree(list->buffer[list->tail].value); 94 list->buffer[list->tail].value = NULL; 95 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1); 96 } 97 out: 98 mutex_unlock(&list->read_mutex); 99 return ret; 100 } 101 102 /* 103 * The first byte of the report buffer is expected to be a report number. 104 */ 105 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type) 106 { 107 unsigned int minor = iminor(file_inode(file)); 108 struct hid_device *dev; 109 __u8 *buf; 110 int ret = 0; 111 112 lockdep_assert_held(&minors_rwsem); 113 114 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) { 115 ret = -ENODEV; 116 goto out; 117 } 118 119 dev = hidraw_table[minor]->hid; 120 121 if (count > HID_MAX_BUFFER_SIZE) { 122 hid_warn(dev, "pid %d passed too large report\n", 123 task_pid_nr(current)); 124 ret = -EINVAL; 125 goto out; 126 } 127 128 if (count < 2) { 129 hid_warn(dev, "pid %d passed too short report\n", 130 task_pid_nr(current)); 131 ret = -EINVAL; 132 goto out; 133 } 134 135 buf = memdup_user(buffer, count); 136 if (IS_ERR(buf)) { 137 ret = PTR_ERR(buf); 138 goto out; 139 } 140 141 if ((report_type == HID_OUTPUT_REPORT) && 142 !(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) { 143 ret = hid_hw_output_report(dev, buf, count); 144 /* 145 * compatibility with old implementation of USB-HID and I2C-HID: 146 * if the device does not support receiving output reports, 147 * on an interrupt endpoint, fallback to SET_REPORT HID command. 148 */ 149 if (ret != -ENOSYS) 150 goto out_free; 151 } 152 153 ret = hid_hw_raw_request(dev, buf[0], buf, count, report_type, 154 HID_REQ_SET_REPORT); 155 156 out_free: 157 kfree(buf); 158 out: 159 return ret; 160 } 161 162 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) 163 { 164 ssize_t ret; 165 down_read(&minors_rwsem); 166 ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT); 167 up_read(&minors_rwsem); 168 return ret; 169 } 170 171 172 /* 173 * This function performs a Get_Report transfer over the control endpoint 174 * per section 7.2.1 of the HID specification, version 1.1. The first byte 175 * of buffer is the report number to request, or 0x0 if the device does not 176 * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT 177 * or HID_INPUT_REPORT. 178 */ 179 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type) 180 { 181 unsigned int minor = iminor(file_inode(file)); 182 struct hid_device *dev; 183 __u8 *buf; 184 int ret = 0, len; 185 unsigned char report_number; 186 187 lockdep_assert_held(&minors_rwsem); 188 189 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) { 190 ret = -ENODEV; 191 goto out; 192 } 193 194 dev = hidraw_table[minor]->hid; 195 196 if (!dev->ll_driver->raw_request) { 197 ret = -ENODEV; 198 goto out; 199 } 200 201 if (count > HID_MAX_BUFFER_SIZE) { 202 hid_warn(dev, "pid %d passed too large report\n", 203 task_pid_nr(current)); 204 ret = -EINVAL; 205 goto out; 206 } 207 208 if (count < 2) { 209 hid_warn(dev, "pid %d passed too short report\n", 210 task_pid_nr(current)); 211 ret = -EINVAL; 212 goto out; 213 } 214 215 buf = kmalloc(count, GFP_KERNEL); 216 if (!buf) { 217 ret = -ENOMEM; 218 goto out; 219 } 220 221 /* 222 * Read the first byte from the user. This is the report number, 223 * which is passed to hid_hw_raw_request(). 224 */ 225 if (copy_from_user(&report_number, buffer, 1)) { 226 ret = -EFAULT; 227 goto out_free; 228 } 229 230 ret = hid_hw_raw_request(dev, report_number, buf, count, report_type, 231 HID_REQ_GET_REPORT); 232 233 if (ret < 0) 234 goto out_free; 235 236 len = (ret < count) ? ret : count; 237 238 if (copy_to_user(buffer, buf, len)) { 239 ret = -EFAULT; 240 goto out_free; 241 } 242 243 ret = len; 244 245 out_free: 246 kfree(buf); 247 out: 248 return ret; 249 } 250 251 static __poll_t hidraw_poll(struct file *file, poll_table *wait) 252 { 253 struct hidraw_list *list = file->private_data; 254 __poll_t mask = EPOLLOUT | EPOLLWRNORM; /* hidraw is always writable */ 255 256 poll_wait(file, &list->hidraw->wait, wait); 257 if (list->head != list->tail) 258 mask |= EPOLLIN | EPOLLRDNORM; 259 if (!list->hidraw->exist) 260 mask |= EPOLLERR | EPOLLHUP; 261 return mask; 262 } 263 264 static int hidraw_open(struct inode *inode, struct file *file) 265 { 266 unsigned int minor = iminor(inode); 267 struct hidraw *dev; 268 struct hidraw_list *list; 269 unsigned long flags; 270 int err = 0; 271 272 if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) { 273 err = -ENOMEM; 274 goto out; 275 } 276 277 /* 278 * Technically not writing to the hidraw_table but a write lock is 279 * required to protect the device refcount. This is symmetrical to 280 * hidraw_release(). 281 */ 282 down_write(&minors_rwsem); 283 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) { 284 err = -ENODEV; 285 goto out_unlock; 286 } 287 288 dev = hidraw_table[minor]; 289 if (!dev->open++) { 290 err = hid_hw_power(dev->hid, PM_HINT_FULLON); 291 if (err < 0) { 292 dev->open--; 293 goto out_unlock; 294 } 295 296 err = hid_hw_open(dev->hid); 297 if (err < 0) { 298 hid_hw_power(dev->hid, PM_HINT_NORMAL); 299 dev->open--; 300 goto out_unlock; 301 } 302 } 303 304 list->hidraw = hidraw_table[minor]; 305 mutex_init(&list->read_mutex); 306 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags); 307 list_add_tail(&list->node, &hidraw_table[minor]->list); 308 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags); 309 file->private_data = list; 310 out_unlock: 311 up_write(&minors_rwsem); 312 out: 313 if (err < 0) 314 kfree(list); 315 return err; 316 317 } 318 319 static int hidraw_fasync(int fd, struct file *file, int on) 320 { 321 struct hidraw_list *list = file->private_data; 322 323 return fasync_helper(fd, file, on, &list->fasync); 324 } 325 326 static void drop_ref(struct hidraw *hidraw, int exists_bit) 327 { 328 if (exists_bit) { 329 hidraw->exist = 0; 330 if (hidraw->open) { 331 hid_hw_close(hidraw->hid); 332 wake_up_interruptible(&hidraw->wait); 333 } 334 device_destroy(&hidraw_class, 335 MKDEV(hidraw_major, hidraw->minor)); 336 } else { 337 --hidraw->open; 338 } 339 if (!hidraw->open) { 340 if (!hidraw->exist) { 341 hidraw_table[hidraw->minor] = NULL; 342 kfree(hidraw); 343 } else { 344 /* close device for last reader */ 345 hid_hw_close(hidraw->hid); 346 hid_hw_power(hidraw->hid, PM_HINT_NORMAL); 347 } 348 } 349 } 350 351 static int hidraw_release(struct inode * inode, struct file * file) 352 { 353 unsigned int minor = iminor(inode); 354 struct hidraw_list *list = file->private_data; 355 unsigned long flags; 356 357 down_write(&minors_rwsem); 358 359 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags); 360 for (int i = list->tail; i < list->head; i++) 361 kfree(list->buffer[i].value); 362 list_del(&list->node); 363 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags); 364 kfree(list); 365 366 drop_ref(hidraw_table[minor], 0); 367 368 up_write(&minors_rwsem); 369 return 0; 370 } 371 372 static long hidraw_ioctl(struct file *file, unsigned int cmd, 373 unsigned long arg) 374 { 375 struct inode *inode = file_inode(file); 376 unsigned int minor = iminor(inode); 377 long ret = 0; 378 struct hidraw *dev; 379 void __user *user_arg = (void __user*) arg; 380 381 down_read(&minors_rwsem); 382 dev = hidraw_table[minor]; 383 if (!dev || !dev->exist) { 384 ret = -ENODEV; 385 goto out; 386 } 387 388 switch (cmd) { 389 case HIDIOCGRDESCSIZE: 390 if (put_user(dev->hid->rsize, (int __user *)arg)) 391 ret = -EFAULT; 392 break; 393 394 case HIDIOCGRDESC: 395 { 396 __u32 len; 397 398 if (get_user(len, (int __user *)arg)) 399 ret = -EFAULT; 400 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1) 401 ret = -EINVAL; 402 else if (copy_to_user(user_arg + offsetof( 403 struct hidraw_report_descriptor, 404 value[0]), 405 dev->hid->rdesc, 406 min(dev->hid->rsize, len))) 407 ret = -EFAULT; 408 break; 409 } 410 case HIDIOCGRAWINFO: 411 { 412 struct hidraw_devinfo dinfo; 413 414 dinfo.bustype = dev->hid->bus; 415 dinfo.vendor = dev->hid->vendor; 416 dinfo.product = dev->hid->product; 417 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo))) 418 ret = -EFAULT; 419 break; 420 } 421 default: 422 { 423 struct hid_device *hid = dev->hid; 424 if (_IOC_TYPE(cmd) != 'H') { 425 ret = -EINVAL; 426 break; 427 } 428 429 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) { 430 int len = _IOC_SIZE(cmd); 431 ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT); 432 break; 433 } 434 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) { 435 int len = _IOC_SIZE(cmd); 436 ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT); 437 break; 438 } 439 440 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSINPUT(0))) { 441 int len = _IOC_SIZE(cmd); 442 ret = hidraw_send_report(file, user_arg, len, HID_INPUT_REPORT); 443 break; 444 } 445 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGINPUT(0))) { 446 int len = _IOC_SIZE(cmd); 447 ret = hidraw_get_report(file, user_arg, len, HID_INPUT_REPORT); 448 break; 449 } 450 451 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSOUTPUT(0))) { 452 int len = _IOC_SIZE(cmd); 453 ret = hidraw_send_report(file, user_arg, len, HID_OUTPUT_REPORT); 454 break; 455 } 456 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGOUTPUT(0))) { 457 int len = _IOC_SIZE(cmd); 458 ret = hidraw_get_report(file, user_arg, len, HID_OUTPUT_REPORT); 459 break; 460 } 461 462 /* Begin Read-only ioctls. */ 463 if (_IOC_DIR(cmd) != _IOC_READ) { 464 ret = -EINVAL; 465 break; 466 } 467 468 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) { 469 int len = strlen(hid->name) + 1; 470 if (len > _IOC_SIZE(cmd)) 471 len = _IOC_SIZE(cmd); 472 ret = copy_to_user(user_arg, hid->name, len) ? 473 -EFAULT : len; 474 break; 475 } 476 477 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) { 478 int len = strlen(hid->phys) + 1; 479 if (len > _IOC_SIZE(cmd)) 480 len = _IOC_SIZE(cmd); 481 ret = copy_to_user(user_arg, hid->phys, len) ? 482 -EFAULT : len; 483 break; 484 } 485 486 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWUNIQ(0))) { 487 int len = strlen(hid->uniq) + 1; 488 if (len > _IOC_SIZE(cmd)) 489 len = _IOC_SIZE(cmd); 490 ret = copy_to_user(user_arg, hid->uniq, len) ? 491 -EFAULT : len; 492 break; 493 } 494 } 495 496 ret = -ENOTTY; 497 } 498 out: 499 up_read(&minors_rwsem); 500 return ret; 501 } 502 503 static const struct file_operations hidraw_ops = { 504 .owner = THIS_MODULE, 505 .read = hidraw_read, 506 .write = hidraw_write, 507 .poll = hidraw_poll, 508 .open = hidraw_open, 509 .release = hidraw_release, 510 .unlocked_ioctl = hidraw_ioctl, 511 .fasync = hidraw_fasync, 512 .compat_ioctl = compat_ptr_ioctl, 513 .llseek = noop_llseek, 514 }; 515 516 int hidraw_report_event(struct hid_device *hid, u8 *data, int len) 517 { 518 struct hidraw *dev = hid->hidraw; 519 struct hidraw_list *list; 520 int ret = 0; 521 unsigned long flags; 522 523 spin_lock_irqsave(&dev->list_lock, flags); 524 list_for_each_entry(list, &dev->list, node) { 525 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1); 526 527 if (new_head == list->tail) 528 continue; 529 530 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) { 531 ret = -ENOMEM; 532 break; 533 } 534 list->buffer[list->head].len = len; 535 list->head = new_head; 536 kill_fasync(&list->fasync, SIGIO, POLL_IN); 537 } 538 spin_unlock_irqrestore(&dev->list_lock, flags); 539 540 wake_up_interruptible(&dev->wait); 541 return ret; 542 } 543 EXPORT_SYMBOL_GPL(hidraw_report_event); 544 545 int hidraw_connect(struct hid_device *hid) 546 { 547 int minor, result; 548 struct hidraw *dev; 549 550 /* we accept any HID device, all applications */ 551 552 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL); 553 if (!dev) 554 return -ENOMEM; 555 556 result = -EINVAL; 557 558 down_write(&minors_rwsem); 559 560 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) { 561 if (hidraw_table[minor]) 562 continue; 563 hidraw_table[minor] = dev; 564 result = 0; 565 break; 566 } 567 568 if (result) { 569 up_write(&minors_rwsem); 570 kfree(dev); 571 goto out; 572 } 573 574 dev->dev = device_create(&hidraw_class, &hid->dev, MKDEV(hidraw_major, minor), 575 NULL, "%s%d", "hidraw", minor); 576 577 if (IS_ERR(dev->dev)) { 578 hidraw_table[minor] = NULL; 579 up_write(&minors_rwsem); 580 result = PTR_ERR(dev->dev); 581 kfree(dev); 582 goto out; 583 } 584 585 init_waitqueue_head(&dev->wait); 586 spin_lock_init(&dev->list_lock); 587 INIT_LIST_HEAD(&dev->list); 588 589 dev->hid = hid; 590 dev->minor = minor; 591 592 dev->exist = 1; 593 hid->hidraw = dev; 594 595 up_write(&minors_rwsem); 596 out: 597 return result; 598 599 } 600 EXPORT_SYMBOL_GPL(hidraw_connect); 601 602 void hidraw_disconnect(struct hid_device *hid) 603 { 604 struct hidraw *hidraw = hid->hidraw; 605 606 down_write(&minors_rwsem); 607 608 drop_ref(hidraw, 1); 609 610 up_write(&minors_rwsem); 611 } 612 EXPORT_SYMBOL_GPL(hidraw_disconnect); 613 614 int __init hidraw_init(void) 615 { 616 int result; 617 dev_t dev_id; 618 619 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR, 620 HIDRAW_MAX_DEVICES, "hidraw"); 621 if (result < 0) { 622 pr_warn("can't get major number\n"); 623 goto out; 624 } 625 626 hidraw_major = MAJOR(dev_id); 627 628 result = class_register(&hidraw_class); 629 if (result) 630 goto error_cdev; 631 632 cdev_init(&hidraw_cdev, &hidraw_ops); 633 result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES); 634 if (result < 0) 635 goto error_class; 636 637 pr_info("raw HID events driver (C) Jiri Kosina\n"); 638 out: 639 return result; 640 641 error_class: 642 class_unregister(&hidraw_class); 643 error_cdev: 644 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 645 goto out; 646 } 647 648 void hidraw_exit(void) 649 { 650 dev_t dev_id = MKDEV(hidraw_major, 0); 651 652 cdev_del(&hidraw_cdev); 653 class_unregister(&hidraw_class); 654 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 655 656 } 657