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