1 /* 2 * HID raw devices, giving access to raw HID events. 3 * 4 * In comparison to hiddev, this device does not process the 5 * hid events at all (no parsing, no lookups). This lets applications 6 * to work on raw hid events as they want to, and avoids a need to 7 * use a transport-specific userspace libhid/libusb libraries. 8 * 9 * Copyright (c) 2007-2014 Jiri Kosina 10 */ 11 12 /* 13 * This program is free software; you can redistribute it and/or modify it 14 * under the terms and conditions of the GNU General Public License, 15 * version 2, as published by the Free Software Foundation. 16 * 17 * You should have received a copy of the GNU General Public License along with 18 * this program; if not, write to the Free Software Foundation, Inc., 19 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. 20 */ 21 22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 23 24 #include <linux/fs.h> 25 #include <linux/module.h> 26 #include <linux/errno.h> 27 #include <linux/kernel.h> 28 #include <linux/init.h> 29 #include <linux/cdev.h> 30 #include <linux/poll.h> 31 #include <linux/device.h> 32 #include <linux/major.h> 33 #include <linux/slab.h> 34 #include <linux/hid.h> 35 #include <linux/mutex.h> 36 #include <linux/sched/signal.h> 37 #include <linux/string.h> 38 39 #include <linux/hidraw.h> 40 41 static int hidraw_major; 42 static struct cdev hidraw_cdev; 43 static struct class *hidraw_class; 44 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES]; 45 static DEFINE_MUTEX(minors_lock); 46 47 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos) 48 { 49 struct hidraw_list *list = file->private_data; 50 int ret = 0, len; 51 DECLARE_WAITQUEUE(wait, current); 52 53 mutex_lock(&list->read_mutex); 54 55 while (ret == 0) { 56 if (list->head == list->tail) { 57 add_wait_queue(&list->hidraw->wait, &wait); 58 set_current_state(TASK_INTERRUPTIBLE); 59 60 while (list->head == list->tail) { 61 if (signal_pending(current)) { 62 ret = -ERESTARTSYS; 63 break; 64 } 65 if (!list->hidraw->exist) { 66 ret = -EIO; 67 break; 68 } 69 if (file->f_flags & O_NONBLOCK) { 70 ret = -EAGAIN; 71 break; 72 } 73 74 /* allow O_NONBLOCK to work well from other threads */ 75 mutex_unlock(&list->read_mutex); 76 schedule(); 77 mutex_lock(&list->read_mutex); 78 set_current_state(TASK_INTERRUPTIBLE); 79 } 80 81 set_current_state(TASK_RUNNING); 82 remove_wait_queue(&list->hidraw->wait, &wait); 83 } 84 85 if (ret) 86 goto out; 87 88 len = list->buffer[list->tail].len > count ? 89 count : list->buffer[list->tail].len; 90 91 if (list->buffer[list->tail].value) { 92 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) { 93 ret = -EFAULT; 94 goto out; 95 } 96 ret = len; 97 } 98 99 kfree(list->buffer[list->tail].value); 100 list->buffer[list->tail].value = NULL; 101 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1); 102 } 103 out: 104 mutex_unlock(&list->read_mutex); 105 return ret; 106 } 107 108 /* 109 * The first byte of the report buffer is expected to be a report number. 110 * 111 * This function is to be called with the minors_lock mutex held. 112 */ 113 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type) 114 { 115 unsigned int minor = iminor(file_inode(file)); 116 struct hid_device *dev; 117 __u8 *buf; 118 int ret = 0; 119 120 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) { 121 ret = -ENODEV; 122 goto out; 123 } 124 125 dev = hidraw_table[minor]->hid; 126 127 if (count > HID_MAX_BUFFER_SIZE) { 128 hid_warn(dev, "pid %d passed too large report\n", 129 task_pid_nr(current)); 130 ret = -EINVAL; 131 goto out; 132 } 133 134 if (count < 2) { 135 hid_warn(dev, "pid %d passed too short report\n", 136 task_pid_nr(current)); 137 ret = -EINVAL; 138 goto out; 139 } 140 141 buf = memdup_user(buffer, count); 142 if (IS_ERR(buf)) { 143 ret = PTR_ERR(buf); 144 goto out; 145 } 146 147 if ((report_type == HID_OUTPUT_REPORT) && 148 !(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) { 149 ret = hid_hw_output_report(dev, buf, count); 150 /* 151 * compatibility with old implementation of USB-HID and I2C-HID: 152 * if the device does not support receiving output reports, 153 * on an interrupt endpoint, fallback to SET_REPORT HID command. 154 */ 155 if (ret != -ENOSYS) 156 goto out_free; 157 } 158 159 ret = hid_hw_raw_request(dev, buf[0], buf, count, report_type, 160 HID_REQ_SET_REPORT); 161 162 out_free: 163 kfree(buf); 164 out: 165 return ret; 166 } 167 168 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) 169 { 170 ssize_t ret; 171 mutex_lock(&minors_lock); 172 ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT); 173 mutex_unlock(&minors_lock); 174 return ret; 175 } 176 177 178 /* 179 * This function performs a Get_Report transfer over the control endpoint 180 * per section 7.2.1 of the HID specification, version 1.1. The first byte 181 * of buffer is the report number to request, or 0x0 if the defice does not 182 * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT 183 * or HID_INPUT_REPORT. 184 * 185 * This function is to be called with the minors_lock mutex held. 186 */ 187 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type) 188 { 189 unsigned int minor = iminor(file_inode(file)); 190 struct hid_device *dev; 191 __u8 *buf; 192 int ret = 0, len; 193 unsigned char report_number; 194 195 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) { 196 ret = -ENODEV; 197 goto out; 198 } 199 200 dev = hidraw_table[minor]->hid; 201 202 if (!dev->ll_driver->raw_request) { 203 ret = -ENODEV; 204 goto out; 205 } 206 207 if (count > HID_MAX_BUFFER_SIZE) { 208 printk(KERN_WARNING "hidraw: pid %d passed too large report\n", 209 task_pid_nr(current)); 210 ret = -EINVAL; 211 goto out; 212 } 213 214 if (count < 2) { 215 printk(KERN_WARNING "hidraw: pid %d passed too short report\n", 216 task_pid_nr(current)); 217 ret = -EINVAL; 218 goto out; 219 } 220 221 buf = kmalloc(count, GFP_KERNEL); 222 if (!buf) { 223 ret = -ENOMEM; 224 goto out; 225 } 226 227 /* 228 * Read the first byte from the user. This is the report number, 229 * which is passed to hid_hw_raw_request(). 230 */ 231 if (copy_from_user(&report_number, buffer, 1)) { 232 ret = -EFAULT; 233 goto out_free; 234 } 235 236 ret = hid_hw_raw_request(dev, report_number, buf, count, report_type, 237 HID_REQ_GET_REPORT); 238 239 if (ret < 0) 240 goto out_free; 241 242 len = (ret < count) ? ret : count; 243 244 if (copy_to_user(buffer, buf, len)) { 245 ret = -EFAULT; 246 goto out_free; 247 } 248 249 ret = len; 250 251 out_free: 252 kfree(buf); 253 out: 254 return ret; 255 } 256 257 static __poll_t hidraw_poll(struct file *file, poll_table *wait) 258 { 259 struct hidraw_list *list = file->private_data; 260 261 poll_wait(file, &list->hidraw->wait, wait); 262 if (list->head != list->tail) 263 return EPOLLIN | EPOLLRDNORM; 264 if (!list->hidraw->exist) 265 return EPOLLERR | EPOLLHUP; 266 return 0; 267 } 268 269 static int hidraw_open(struct inode *inode, struct file *file) 270 { 271 unsigned int minor = iminor(inode); 272 struct hidraw *dev; 273 struct hidraw_list *list; 274 unsigned long flags; 275 int err = 0; 276 277 if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) { 278 err = -ENOMEM; 279 goto out; 280 } 281 282 mutex_lock(&minors_lock); 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 mutex_unlock(&minors_lock); 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 mutex_lock(&minors_lock); 358 359 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags); 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 mutex_unlock(&minors_lock); 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 mutex_lock(&minors_lock); 380 dev = hidraw_table[minor]; 381 if (!dev) { 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 /* Begin Read-only ioctls. */ 439 if (_IOC_DIR(cmd) != _IOC_READ) { 440 ret = -EINVAL; 441 break; 442 } 443 444 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) { 445 int len = strlen(hid->name) + 1; 446 if (len > _IOC_SIZE(cmd)) 447 len = _IOC_SIZE(cmd); 448 ret = copy_to_user(user_arg, hid->name, len) ? 449 -EFAULT : len; 450 break; 451 } 452 453 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) { 454 int len = strlen(hid->phys) + 1; 455 if (len > _IOC_SIZE(cmd)) 456 len = _IOC_SIZE(cmd); 457 ret = copy_to_user(user_arg, hid->phys, len) ? 458 -EFAULT : len; 459 break; 460 } 461 } 462 463 ret = -ENOTTY; 464 } 465 out: 466 mutex_unlock(&minors_lock); 467 return ret; 468 } 469 470 static const struct file_operations hidraw_ops = { 471 .owner = THIS_MODULE, 472 .read = hidraw_read, 473 .write = hidraw_write, 474 .poll = hidraw_poll, 475 .open = hidraw_open, 476 .release = hidraw_release, 477 .unlocked_ioctl = hidraw_ioctl, 478 .fasync = hidraw_fasync, 479 #ifdef CONFIG_COMPAT 480 .compat_ioctl = hidraw_ioctl, 481 #endif 482 .llseek = noop_llseek, 483 }; 484 485 int hidraw_report_event(struct hid_device *hid, u8 *data, int len) 486 { 487 struct hidraw *dev = hid->hidraw; 488 struct hidraw_list *list; 489 int ret = 0; 490 unsigned long flags; 491 492 spin_lock_irqsave(&dev->list_lock, flags); 493 list_for_each_entry(list, &dev->list, node) { 494 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1); 495 496 if (new_head == list->tail) 497 continue; 498 499 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) { 500 ret = -ENOMEM; 501 break; 502 } 503 list->buffer[list->head].len = len; 504 list->head = new_head; 505 kill_fasync(&list->fasync, SIGIO, POLL_IN); 506 } 507 spin_unlock_irqrestore(&dev->list_lock, flags); 508 509 wake_up_interruptible(&dev->wait); 510 return ret; 511 } 512 EXPORT_SYMBOL_GPL(hidraw_report_event); 513 514 int hidraw_connect(struct hid_device *hid) 515 { 516 int minor, result; 517 struct hidraw *dev; 518 519 /* we accept any HID device, all applications */ 520 521 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL); 522 if (!dev) 523 return -ENOMEM; 524 525 result = -EINVAL; 526 527 mutex_lock(&minors_lock); 528 529 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) { 530 if (hidraw_table[minor]) 531 continue; 532 hidraw_table[minor] = dev; 533 result = 0; 534 break; 535 } 536 537 if (result) { 538 mutex_unlock(&minors_lock); 539 kfree(dev); 540 goto out; 541 } 542 543 dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor), 544 NULL, "%s%d", "hidraw", minor); 545 546 if (IS_ERR(dev->dev)) { 547 hidraw_table[minor] = NULL; 548 mutex_unlock(&minors_lock); 549 result = PTR_ERR(dev->dev); 550 kfree(dev); 551 goto out; 552 } 553 554 init_waitqueue_head(&dev->wait); 555 spin_lock_init(&dev->list_lock); 556 INIT_LIST_HEAD(&dev->list); 557 558 dev->hid = hid; 559 dev->minor = minor; 560 561 dev->exist = 1; 562 hid->hidraw = dev; 563 564 mutex_unlock(&minors_lock); 565 out: 566 return result; 567 568 } 569 EXPORT_SYMBOL_GPL(hidraw_connect); 570 571 void hidraw_disconnect(struct hid_device *hid) 572 { 573 struct hidraw *hidraw = hid->hidraw; 574 575 mutex_lock(&minors_lock); 576 577 drop_ref(hidraw, 1); 578 579 mutex_unlock(&minors_lock); 580 } 581 EXPORT_SYMBOL_GPL(hidraw_disconnect); 582 583 int __init hidraw_init(void) 584 { 585 int result; 586 dev_t dev_id; 587 588 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR, 589 HIDRAW_MAX_DEVICES, "hidraw"); 590 if (result < 0) { 591 pr_warn("can't get major number\n"); 592 goto out; 593 } 594 595 hidraw_major = MAJOR(dev_id); 596 597 hidraw_class = class_create(THIS_MODULE, "hidraw"); 598 if (IS_ERR(hidraw_class)) { 599 result = PTR_ERR(hidraw_class); 600 goto error_cdev; 601 } 602 603 cdev_init(&hidraw_cdev, &hidraw_ops); 604 result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES); 605 if (result < 0) 606 goto error_class; 607 608 printk(KERN_INFO "hidraw: raw HID events driver (C) Jiri Kosina\n"); 609 out: 610 return result; 611 612 error_class: 613 class_destroy(hidraw_class); 614 error_cdev: 615 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 616 goto out; 617 } 618 619 void hidraw_exit(void) 620 { 621 dev_t dev_id = MKDEV(hidraw_major, 0); 622 623 cdev_del(&hidraw_cdev); 624 class_destroy(hidraw_class); 625 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 626 627 } 628