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, (u64)(long)file, false); 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, (u64)(long)file, false); 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, (u64)(long)file, false); 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 while (list->tail != list->head) { 361 kfree(list->buffer[list->tail].value); 362 list->buffer[list->tail].value = NULL; 363 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1); 364 } 365 list_del(&list->node); 366 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags); 367 kfree(list); 368 369 drop_ref(hidraw_table[minor], 0); 370 371 up_write(&minors_rwsem); 372 return 0; 373 } 374 375 static long hidraw_ioctl(struct file *file, unsigned int cmd, 376 unsigned long arg) 377 { 378 struct inode *inode = file_inode(file); 379 unsigned int minor = iminor(inode); 380 long ret = 0; 381 struct hidraw *dev; 382 void __user *user_arg = (void __user*) arg; 383 384 down_read(&minors_rwsem); 385 dev = hidraw_table[minor]; 386 if (!dev || !dev->exist) { 387 ret = -ENODEV; 388 goto out; 389 } 390 391 switch (cmd) { 392 case HIDIOCGRDESCSIZE: 393 if (put_user(dev->hid->rsize, (int __user *)arg)) 394 ret = -EFAULT; 395 break; 396 397 case HIDIOCGRDESC: 398 { 399 __u32 len; 400 401 if (get_user(len, (int __user *)arg)) 402 ret = -EFAULT; 403 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1) 404 ret = -EINVAL; 405 else if (copy_to_user(user_arg + offsetof( 406 struct hidraw_report_descriptor, 407 value[0]), 408 dev->hid->rdesc, 409 min(dev->hid->rsize, len))) 410 ret = -EFAULT; 411 break; 412 } 413 case HIDIOCGRAWINFO: 414 { 415 struct hidraw_devinfo dinfo; 416 417 dinfo.bustype = dev->hid->bus; 418 dinfo.vendor = dev->hid->vendor; 419 dinfo.product = dev->hid->product; 420 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo))) 421 ret = -EFAULT; 422 break; 423 } 424 default: 425 { 426 struct hid_device *hid = dev->hid; 427 if (_IOC_TYPE(cmd) != 'H') { 428 ret = -EINVAL; 429 break; 430 } 431 432 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) { 433 int len = _IOC_SIZE(cmd); 434 ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT); 435 break; 436 } 437 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) { 438 int len = _IOC_SIZE(cmd); 439 ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT); 440 break; 441 } 442 443 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSINPUT(0))) { 444 int len = _IOC_SIZE(cmd); 445 ret = hidraw_send_report(file, user_arg, len, HID_INPUT_REPORT); 446 break; 447 } 448 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGINPUT(0))) { 449 int len = _IOC_SIZE(cmd); 450 ret = hidraw_get_report(file, user_arg, len, HID_INPUT_REPORT); 451 break; 452 } 453 454 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSOUTPUT(0))) { 455 int len = _IOC_SIZE(cmd); 456 ret = hidraw_send_report(file, user_arg, len, HID_OUTPUT_REPORT); 457 break; 458 } 459 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGOUTPUT(0))) { 460 int len = _IOC_SIZE(cmd); 461 ret = hidraw_get_report(file, user_arg, len, HID_OUTPUT_REPORT); 462 break; 463 } 464 465 /* Begin Read-only ioctls. */ 466 if (_IOC_DIR(cmd) != _IOC_READ) { 467 ret = -EINVAL; 468 break; 469 } 470 471 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) { 472 int len = strlen(hid->name) + 1; 473 if (len > _IOC_SIZE(cmd)) 474 len = _IOC_SIZE(cmd); 475 ret = copy_to_user(user_arg, hid->name, len) ? 476 -EFAULT : len; 477 break; 478 } 479 480 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) { 481 int len = strlen(hid->phys) + 1; 482 if (len > _IOC_SIZE(cmd)) 483 len = _IOC_SIZE(cmd); 484 ret = copy_to_user(user_arg, hid->phys, len) ? 485 -EFAULT : len; 486 break; 487 } 488 489 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWUNIQ(0))) { 490 int len = strlen(hid->uniq) + 1; 491 if (len > _IOC_SIZE(cmd)) 492 len = _IOC_SIZE(cmd); 493 ret = copy_to_user(user_arg, hid->uniq, len) ? 494 -EFAULT : len; 495 break; 496 } 497 } 498 499 ret = -ENOTTY; 500 } 501 out: 502 up_read(&minors_rwsem); 503 return ret; 504 } 505 506 static const struct file_operations hidraw_ops = { 507 .owner = THIS_MODULE, 508 .read = hidraw_read, 509 .write = hidraw_write, 510 .poll = hidraw_poll, 511 .open = hidraw_open, 512 .release = hidraw_release, 513 .unlocked_ioctl = hidraw_ioctl, 514 .fasync = hidraw_fasync, 515 .compat_ioctl = compat_ptr_ioctl, 516 .llseek = noop_llseek, 517 }; 518 519 int hidraw_report_event(struct hid_device *hid, u8 *data, int len) 520 { 521 struct hidraw *dev = hid->hidraw; 522 struct hidraw_list *list; 523 int ret = 0; 524 unsigned long flags; 525 526 spin_lock_irqsave(&dev->list_lock, flags); 527 list_for_each_entry(list, &dev->list, node) { 528 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1); 529 530 if (new_head == list->tail) 531 continue; 532 533 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) { 534 ret = -ENOMEM; 535 break; 536 } 537 list->buffer[list->head].len = len; 538 list->head = new_head; 539 kill_fasync(&list->fasync, SIGIO, POLL_IN); 540 } 541 spin_unlock_irqrestore(&dev->list_lock, flags); 542 543 wake_up_interruptible(&dev->wait); 544 return ret; 545 } 546 EXPORT_SYMBOL_GPL(hidraw_report_event); 547 548 int hidraw_connect(struct hid_device *hid) 549 { 550 int minor, result; 551 struct hidraw *dev; 552 553 /* we accept any HID device, all applications */ 554 555 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL); 556 if (!dev) 557 return -ENOMEM; 558 559 result = -EINVAL; 560 561 down_write(&minors_rwsem); 562 563 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) { 564 if (hidraw_table[minor]) 565 continue; 566 hidraw_table[minor] = dev; 567 result = 0; 568 break; 569 } 570 571 if (result) { 572 up_write(&minors_rwsem); 573 kfree(dev); 574 goto out; 575 } 576 577 dev->dev = device_create(&hidraw_class, &hid->dev, MKDEV(hidraw_major, minor), 578 NULL, "%s%d", "hidraw", minor); 579 580 if (IS_ERR(dev->dev)) { 581 hidraw_table[minor] = NULL; 582 up_write(&minors_rwsem); 583 result = PTR_ERR(dev->dev); 584 kfree(dev); 585 goto out; 586 } 587 588 init_waitqueue_head(&dev->wait); 589 spin_lock_init(&dev->list_lock); 590 INIT_LIST_HEAD(&dev->list); 591 592 dev->hid = hid; 593 dev->minor = minor; 594 595 dev->exist = 1; 596 hid->hidraw = dev; 597 598 up_write(&minors_rwsem); 599 out: 600 return result; 601 602 } 603 EXPORT_SYMBOL_GPL(hidraw_connect); 604 605 void hidraw_disconnect(struct hid_device *hid) 606 { 607 struct hidraw *hidraw = hid->hidraw; 608 609 down_write(&minors_rwsem); 610 611 drop_ref(hidraw, 1); 612 613 up_write(&minors_rwsem); 614 } 615 EXPORT_SYMBOL_GPL(hidraw_disconnect); 616 617 int __init hidraw_init(void) 618 { 619 int result; 620 dev_t dev_id; 621 622 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR, 623 HIDRAW_MAX_DEVICES, "hidraw"); 624 if (result < 0) { 625 pr_warn("can't get major number\n"); 626 goto out; 627 } 628 629 hidraw_major = MAJOR(dev_id); 630 631 result = class_register(&hidraw_class); 632 if (result) 633 goto error_cdev; 634 635 cdev_init(&hidraw_cdev, &hidraw_ops); 636 result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES); 637 if (result < 0) 638 goto error_class; 639 640 pr_info("raw HID events driver (C) Jiri Kosina\n"); 641 out: 642 return result; 643 644 error_class: 645 class_unregister(&hidraw_class); 646 error_cdev: 647 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 648 goto out; 649 } 650 651 void hidraw_exit(void) 652 { 653 dev_t dev_id = MKDEV(hidraw_major, 0); 654 655 cdev_del(&hidraw_cdev); 656 class_unregister(&hidraw_class); 657 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 658 659 } 660