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 defice 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; 252 253 poll_wait(file, &list->hidraw->wait, wait); 254 if (list->head != list->tail) 255 return EPOLLIN | EPOLLRDNORM | EPOLLOUT; 256 if (!list->hidraw->exist) 257 return EPOLLERR | EPOLLHUP; 258 return 0; 259 } 260 261 static int hidraw_open(struct inode *inode, struct file *file) 262 { 263 unsigned int minor = iminor(inode); 264 struct hidraw *dev; 265 struct hidraw_list *list; 266 unsigned long flags; 267 int err = 0; 268 269 if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) { 270 err = -ENOMEM; 271 goto out; 272 } 273 274 mutex_lock(&minors_lock); 275 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) { 276 err = -ENODEV; 277 goto out_unlock; 278 } 279 280 dev = hidraw_table[minor]; 281 if (!dev->open++) { 282 err = hid_hw_power(dev->hid, PM_HINT_FULLON); 283 if (err < 0) { 284 dev->open--; 285 goto out_unlock; 286 } 287 288 err = hid_hw_open(dev->hid); 289 if (err < 0) { 290 hid_hw_power(dev->hid, PM_HINT_NORMAL); 291 dev->open--; 292 goto out_unlock; 293 } 294 } 295 296 list->hidraw = hidraw_table[minor]; 297 mutex_init(&list->read_mutex); 298 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags); 299 list_add_tail(&list->node, &hidraw_table[minor]->list); 300 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags); 301 file->private_data = list; 302 out_unlock: 303 mutex_unlock(&minors_lock); 304 out: 305 if (err < 0) 306 kfree(list); 307 return err; 308 309 } 310 311 static int hidraw_fasync(int fd, struct file *file, int on) 312 { 313 struct hidraw_list *list = file->private_data; 314 315 return fasync_helper(fd, file, on, &list->fasync); 316 } 317 318 static void drop_ref(struct hidraw *hidraw, int exists_bit) 319 { 320 if (exists_bit) { 321 hidraw->exist = 0; 322 if (hidraw->open) { 323 hid_hw_close(hidraw->hid); 324 wake_up_interruptible(&hidraw->wait); 325 } 326 device_destroy(hidraw_class, 327 MKDEV(hidraw_major, hidraw->minor)); 328 } else { 329 --hidraw->open; 330 } 331 if (!hidraw->open) { 332 if (!hidraw->exist) { 333 hidraw_table[hidraw->minor] = NULL; 334 kfree(hidraw); 335 } else { 336 /* close device for last reader */ 337 hid_hw_close(hidraw->hid); 338 hid_hw_power(hidraw->hid, PM_HINT_NORMAL); 339 } 340 } 341 } 342 343 static int hidraw_release(struct inode * inode, struct file * file) 344 { 345 unsigned int minor = iminor(inode); 346 struct hidraw_list *list = file->private_data; 347 unsigned long flags; 348 349 mutex_lock(&minors_lock); 350 351 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags); 352 list_del(&list->node); 353 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags); 354 kfree(list); 355 356 drop_ref(hidraw_table[minor], 0); 357 358 mutex_unlock(&minors_lock); 359 return 0; 360 } 361 362 static long hidraw_ioctl(struct file *file, unsigned int cmd, 363 unsigned long arg) 364 { 365 struct inode *inode = file_inode(file); 366 unsigned int minor = iminor(inode); 367 long ret = 0; 368 struct hidraw *dev; 369 void __user *user_arg = (void __user*) arg; 370 371 mutex_lock(&minors_lock); 372 dev = hidraw_table[minor]; 373 if (!dev || !dev->exist) { 374 ret = -ENODEV; 375 goto out; 376 } 377 378 switch (cmd) { 379 case HIDIOCGRDESCSIZE: 380 if (put_user(dev->hid->rsize, (int __user *)arg)) 381 ret = -EFAULT; 382 break; 383 384 case HIDIOCGRDESC: 385 { 386 __u32 len; 387 388 if (get_user(len, (int __user *)arg)) 389 ret = -EFAULT; 390 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1) 391 ret = -EINVAL; 392 else if (copy_to_user(user_arg + offsetof( 393 struct hidraw_report_descriptor, 394 value[0]), 395 dev->hid->rdesc, 396 min(dev->hid->rsize, len))) 397 ret = -EFAULT; 398 break; 399 } 400 case HIDIOCGRAWINFO: 401 { 402 struct hidraw_devinfo dinfo; 403 404 dinfo.bustype = dev->hid->bus; 405 dinfo.vendor = dev->hid->vendor; 406 dinfo.product = dev->hid->product; 407 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo))) 408 ret = -EFAULT; 409 break; 410 } 411 default: 412 { 413 struct hid_device *hid = dev->hid; 414 if (_IOC_TYPE(cmd) != 'H') { 415 ret = -EINVAL; 416 break; 417 } 418 419 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) { 420 int len = _IOC_SIZE(cmd); 421 ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT); 422 break; 423 } 424 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) { 425 int len = _IOC_SIZE(cmd); 426 ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT); 427 break; 428 } 429 430 /* Begin Read-only ioctls. */ 431 if (_IOC_DIR(cmd) != _IOC_READ) { 432 ret = -EINVAL; 433 break; 434 } 435 436 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) { 437 int len = strlen(hid->name) + 1; 438 if (len > _IOC_SIZE(cmd)) 439 len = _IOC_SIZE(cmd); 440 ret = copy_to_user(user_arg, hid->name, len) ? 441 -EFAULT : len; 442 break; 443 } 444 445 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) { 446 int len = strlen(hid->phys) + 1; 447 if (len > _IOC_SIZE(cmd)) 448 len = _IOC_SIZE(cmd); 449 ret = copy_to_user(user_arg, hid->phys, len) ? 450 -EFAULT : len; 451 break; 452 } 453 } 454 455 ret = -ENOTTY; 456 } 457 out: 458 mutex_unlock(&minors_lock); 459 return ret; 460 } 461 462 static const struct file_operations hidraw_ops = { 463 .owner = THIS_MODULE, 464 .read = hidraw_read, 465 .write = hidraw_write, 466 .poll = hidraw_poll, 467 .open = hidraw_open, 468 .release = hidraw_release, 469 .unlocked_ioctl = hidraw_ioctl, 470 .fasync = hidraw_fasync, 471 .compat_ioctl = compat_ptr_ioctl, 472 .llseek = noop_llseek, 473 }; 474 475 int hidraw_report_event(struct hid_device *hid, u8 *data, int len) 476 { 477 struct hidraw *dev = hid->hidraw; 478 struct hidraw_list *list; 479 int ret = 0; 480 unsigned long flags; 481 482 spin_lock_irqsave(&dev->list_lock, flags); 483 list_for_each_entry(list, &dev->list, node) { 484 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1); 485 486 if (new_head == list->tail) 487 continue; 488 489 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) { 490 ret = -ENOMEM; 491 break; 492 } 493 list->buffer[list->head].len = len; 494 list->head = new_head; 495 kill_fasync(&list->fasync, SIGIO, POLL_IN); 496 } 497 spin_unlock_irqrestore(&dev->list_lock, flags); 498 499 wake_up_interruptible(&dev->wait); 500 return ret; 501 } 502 EXPORT_SYMBOL_GPL(hidraw_report_event); 503 504 int hidraw_connect(struct hid_device *hid) 505 { 506 int minor, result; 507 struct hidraw *dev; 508 509 /* we accept any HID device, all applications */ 510 511 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL); 512 if (!dev) 513 return -ENOMEM; 514 515 result = -EINVAL; 516 517 mutex_lock(&minors_lock); 518 519 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) { 520 if (hidraw_table[minor]) 521 continue; 522 hidraw_table[minor] = dev; 523 result = 0; 524 break; 525 } 526 527 if (result) { 528 mutex_unlock(&minors_lock); 529 kfree(dev); 530 goto out; 531 } 532 533 dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor), 534 NULL, "%s%d", "hidraw", minor); 535 536 if (IS_ERR(dev->dev)) { 537 hidraw_table[minor] = NULL; 538 mutex_unlock(&minors_lock); 539 result = PTR_ERR(dev->dev); 540 kfree(dev); 541 goto out; 542 } 543 544 init_waitqueue_head(&dev->wait); 545 spin_lock_init(&dev->list_lock); 546 INIT_LIST_HEAD(&dev->list); 547 548 dev->hid = hid; 549 dev->minor = minor; 550 551 dev->exist = 1; 552 hid->hidraw = dev; 553 554 mutex_unlock(&minors_lock); 555 out: 556 return result; 557 558 } 559 EXPORT_SYMBOL_GPL(hidraw_connect); 560 561 void hidraw_disconnect(struct hid_device *hid) 562 { 563 struct hidraw *hidraw = hid->hidraw; 564 565 mutex_lock(&minors_lock); 566 567 drop_ref(hidraw, 1); 568 569 mutex_unlock(&minors_lock); 570 } 571 EXPORT_SYMBOL_GPL(hidraw_disconnect); 572 573 int __init hidraw_init(void) 574 { 575 int result; 576 dev_t dev_id; 577 578 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR, 579 HIDRAW_MAX_DEVICES, "hidraw"); 580 if (result < 0) { 581 pr_warn("can't get major number\n"); 582 goto out; 583 } 584 585 hidraw_major = MAJOR(dev_id); 586 587 hidraw_class = class_create(THIS_MODULE, "hidraw"); 588 if (IS_ERR(hidraw_class)) { 589 result = PTR_ERR(hidraw_class); 590 goto error_cdev; 591 } 592 593 cdev_init(&hidraw_cdev, &hidraw_ops); 594 result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES); 595 if (result < 0) 596 goto error_class; 597 598 pr_info("raw HID events driver (C) Jiri Kosina\n"); 599 out: 600 return result; 601 602 error_class: 603 class_destroy(hidraw_class); 604 error_cdev: 605 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 606 goto out; 607 } 608 609 void hidraw_exit(void) 610 { 611 dev_t dev_id = MKDEV(hidraw_major, 0); 612 613 cdev_del(&hidraw_cdev); 614 class_destroy(hidraw_class); 615 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 616 617 } 618