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