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 DEFINE_MUTEX(minors_lock); 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_lock); 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 mutex_lock(&minors_lock); 164 ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT); 165 mutex_unlock(&minors_lock); 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_lock); 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 mutex_lock(&minors_lock); 276 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) { 277 err = -ENODEV; 278 goto out_unlock; 279 } 280 281 dev = hidraw_table[minor]; 282 if (!dev->open++) { 283 err = hid_hw_power(dev->hid, PM_HINT_FULLON); 284 if (err < 0) { 285 dev->open--; 286 goto out_unlock; 287 } 288 289 err = hid_hw_open(dev->hid); 290 if (err < 0) { 291 hid_hw_power(dev->hid, PM_HINT_NORMAL); 292 dev->open--; 293 goto out_unlock; 294 } 295 } 296 297 list->hidraw = hidraw_table[minor]; 298 mutex_init(&list->read_mutex); 299 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags); 300 list_add_tail(&list->node, &hidraw_table[minor]->list); 301 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags); 302 file->private_data = list; 303 out_unlock: 304 mutex_unlock(&minors_lock); 305 out: 306 if (err < 0) 307 kfree(list); 308 return err; 309 310 } 311 312 static int hidraw_fasync(int fd, struct file *file, int on) 313 { 314 struct hidraw_list *list = file->private_data; 315 316 return fasync_helper(fd, file, on, &list->fasync); 317 } 318 319 static void drop_ref(struct hidraw *hidraw, int exists_bit) 320 { 321 if (exists_bit) { 322 hidraw->exist = 0; 323 if (hidraw->open) { 324 hid_hw_close(hidraw->hid); 325 wake_up_interruptible(&hidraw->wait); 326 } 327 device_destroy(hidraw_class, 328 MKDEV(hidraw_major, hidraw->minor)); 329 } else { 330 --hidraw->open; 331 } 332 if (!hidraw->open) { 333 if (!hidraw->exist) { 334 hidraw_table[hidraw->minor] = NULL; 335 kfree(hidraw); 336 } else { 337 /* close device for last reader */ 338 hid_hw_close(hidraw->hid); 339 hid_hw_power(hidraw->hid, PM_HINT_NORMAL); 340 } 341 } 342 } 343 344 static int hidraw_release(struct inode * inode, struct file * file) 345 { 346 unsigned int minor = iminor(inode); 347 struct hidraw_list *list = file->private_data; 348 unsigned long flags; 349 int i; 350 351 mutex_lock(&minors_lock); 352 353 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags); 354 for (i = list->tail; i < list->head; i++) 355 kfree(list->buffer[i].value); 356 list_del(&list->node); 357 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags); 358 kfree(list); 359 360 drop_ref(hidraw_table[minor], 0); 361 362 mutex_unlock(&minors_lock); 363 return 0; 364 } 365 366 static long hidraw_ioctl(struct file *file, unsigned int cmd, 367 unsigned long arg) 368 { 369 struct inode *inode = file_inode(file); 370 unsigned int minor = iminor(inode); 371 long ret = 0; 372 struct hidraw *dev; 373 void __user *user_arg = (void __user*) arg; 374 375 mutex_lock(&minors_lock); 376 dev = hidraw_table[minor]; 377 if (!dev || !dev->exist) { 378 ret = -ENODEV; 379 goto out; 380 } 381 382 switch (cmd) { 383 case HIDIOCGRDESCSIZE: 384 if (put_user(dev->hid->rsize, (int __user *)arg)) 385 ret = -EFAULT; 386 break; 387 388 case HIDIOCGRDESC: 389 { 390 __u32 len; 391 392 if (get_user(len, (int __user *)arg)) 393 ret = -EFAULT; 394 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1) 395 ret = -EINVAL; 396 else if (copy_to_user(user_arg + offsetof( 397 struct hidraw_report_descriptor, 398 value[0]), 399 dev->hid->rdesc, 400 min(dev->hid->rsize, len))) 401 ret = -EFAULT; 402 break; 403 } 404 case HIDIOCGRAWINFO: 405 { 406 struct hidraw_devinfo dinfo; 407 408 dinfo.bustype = dev->hid->bus; 409 dinfo.vendor = dev->hid->vendor; 410 dinfo.product = dev->hid->product; 411 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo))) 412 ret = -EFAULT; 413 break; 414 } 415 default: 416 { 417 struct hid_device *hid = dev->hid; 418 if (_IOC_TYPE(cmd) != 'H') { 419 ret = -EINVAL; 420 break; 421 } 422 423 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) { 424 int len = _IOC_SIZE(cmd); 425 ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT); 426 break; 427 } 428 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) { 429 int len = _IOC_SIZE(cmd); 430 ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT); 431 break; 432 } 433 434 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSINPUT(0))) { 435 int len = _IOC_SIZE(cmd); 436 ret = hidraw_send_report(file, user_arg, len, HID_INPUT_REPORT); 437 break; 438 } 439 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGINPUT(0))) { 440 int len = _IOC_SIZE(cmd); 441 ret = hidraw_get_report(file, user_arg, len, HID_INPUT_REPORT); 442 break; 443 } 444 445 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSOUTPUT(0))) { 446 int len = _IOC_SIZE(cmd); 447 ret = hidraw_send_report(file, user_arg, len, HID_OUTPUT_REPORT); 448 break; 449 } 450 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGOUTPUT(0))) { 451 int len = _IOC_SIZE(cmd); 452 ret = hidraw_get_report(file, user_arg, len, HID_OUTPUT_REPORT); 453 break; 454 } 455 456 /* Begin Read-only ioctls. */ 457 if (_IOC_DIR(cmd) != _IOC_READ) { 458 ret = -EINVAL; 459 break; 460 } 461 462 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) { 463 int len = strlen(hid->name) + 1; 464 if (len > _IOC_SIZE(cmd)) 465 len = _IOC_SIZE(cmd); 466 ret = copy_to_user(user_arg, hid->name, len) ? 467 -EFAULT : len; 468 break; 469 } 470 471 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) { 472 int len = strlen(hid->phys) + 1; 473 if (len > _IOC_SIZE(cmd)) 474 len = _IOC_SIZE(cmd); 475 ret = copy_to_user(user_arg, hid->phys, len) ? 476 -EFAULT : len; 477 break; 478 } 479 480 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWUNIQ(0))) { 481 int len = strlen(hid->uniq) + 1; 482 if (len > _IOC_SIZE(cmd)) 483 len = _IOC_SIZE(cmd); 484 ret = copy_to_user(user_arg, hid->uniq, len) ? 485 -EFAULT : len; 486 break; 487 } 488 } 489 490 ret = -ENOTTY; 491 } 492 out: 493 mutex_unlock(&minors_lock); 494 return ret; 495 } 496 497 static const struct file_operations hidraw_ops = { 498 .owner = THIS_MODULE, 499 .read = hidraw_read, 500 .write = hidraw_write, 501 .poll = hidraw_poll, 502 .open = hidraw_open, 503 .release = hidraw_release, 504 .unlocked_ioctl = hidraw_ioctl, 505 .fasync = hidraw_fasync, 506 .compat_ioctl = compat_ptr_ioctl, 507 .llseek = noop_llseek, 508 }; 509 510 int hidraw_report_event(struct hid_device *hid, u8 *data, int len) 511 { 512 struct hidraw *dev = hid->hidraw; 513 struct hidraw_list *list; 514 int ret = 0; 515 unsigned long flags; 516 517 spin_lock_irqsave(&dev->list_lock, flags); 518 list_for_each_entry(list, &dev->list, node) { 519 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1); 520 521 if (new_head == list->tail) 522 continue; 523 524 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) { 525 ret = -ENOMEM; 526 break; 527 } 528 list->buffer[list->head].len = len; 529 list->head = new_head; 530 kill_fasync(&list->fasync, SIGIO, POLL_IN); 531 } 532 spin_unlock_irqrestore(&dev->list_lock, flags); 533 534 wake_up_interruptible(&dev->wait); 535 return ret; 536 } 537 EXPORT_SYMBOL_GPL(hidraw_report_event); 538 539 int hidraw_connect(struct hid_device *hid) 540 { 541 int minor, result; 542 struct hidraw *dev; 543 544 /* we accept any HID device, all applications */ 545 546 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL); 547 if (!dev) 548 return -ENOMEM; 549 550 result = -EINVAL; 551 552 mutex_lock(&minors_lock); 553 554 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) { 555 if (hidraw_table[minor]) 556 continue; 557 hidraw_table[minor] = dev; 558 result = 0; 559 break; 560 } 561 562 if (result) { 563 mutex_unlock(&minors_lock); 564 kfree(dev); 565 goto out; 566 } 567 568 dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor), 569 NULL, "%s%d", "hidraw", minor); 570 571 if (IS_ERR(dev->dev)) { 572 hidraw_table[minor] = NULL; 573 mutex_unlock(&minors_lock); 574 result = PTR_ERR(dev->dev); 575 kfree(dev); 576 goto out; 577 } 578 579 init_waitqueue_head(&dev->wait); 580 spin_lock_init(&dev->list_lock); 581 INIT_LIST_HEAD(&dev->list); 582 583 dev->hid = hid; 584 dev->minor = minor; 585 586 dev->exist = 1; 587 hid->hidraw = dev; 588 589 mutex_unlock(&minors_lock); 590 out: 591 return result; 592 593 } 594 EXPORT_SYMBOL_GPL(hidraw_connect); 595 596 void hidraw_disconnect(struct hid_device *hid) 597 { 598 struct hidraw *hidraw = hid->hidraw; 599 600 mutex_lock(&minors_lock); 601 602 drop_ref(hidraw, 1); 603 604 mutex_unlock(&minors_lock); 605 } 606 EXPORT_SYMBOL_GPL(hidraw_disconnect); 607 608 int __init hidraw_init(void) 609 { 610 int result; 611 dev_t dev_id; 612 613 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR, 614 HIDRAW_MAX_DEVICES, "hidraw"); 615 if (result < 0) { 616 pr_warn("can't get major number\n"); 617 goto out; 618 } 619 620 hidraw_major = MAJOR(dev_id); 621 622 hidraw_class = class_create(THIS_MODULE, "hidraw"); 623 if (IS_ERR(hidraw_class)) { 624 result = PTR_ERR(hidraw_class); 625 goto error_cdev; 626 } 627 628 cdev_init(&hidraw_cdev, &hidraw_ops); 629 result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES); 630 if (result < 0) 631 goto error_class; 632 633 pr_info("raw HID events driver (C) Jiri Kosina\n"); 634 out: 635 return result; 636 637 error_class: 638 class_destroy(hidraw_class); 639 error_cdev: 640 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 641 goto out; 642 } 643 644 void hidraw_exit(void) 645 { 646 dev_t dev_id = MKDEV(hidraw_major, 0); 647 648 cdev_del(&hidraw_cdev); 649 class_destroy(hidraw_class); 650 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 651 652 } 653