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 dev = hidraw_table[minor]->hid; 196 197 if (!dev->ll_driver->raw_request) { 198 ret = -ENODEV; 199 goto out; 200 } 201 202 if (count > HID_MAX_BUFFER_SIZE) { 203 printk(KERN_WARNING "hidraw: pid %d passed too large report\n", 204 task_pid_nr(current)); 205 ret = -EINVAL; 206 goto out; 207 } 208 209 if (count < 2) { 210 printk(KERN_WARNING "hidraw: pid %d passed too short report\n", 211 task_pid_nr(current)); 212 ret = -EINVAL; 213 goto out; 214 } 215 216 buf = kmalloc(count * sizeof(__u8), GFP_KERNEL); 217 if (!buf) { 218 ret = -ENOMEM; 219 goto out; 220 } 221 222 /* 223 * Read the first byte from the user. This is the report number, 224 * which is passed to hid_hw_raw_request(). 225 */ 226 if (copy_from_user(&report_number, buffer, 1)) { 227 ret = -EFAULT; 228 goto out_free; 229 } 230 231 ret = hid_hw_raw_request(dev, report_number, buf, count, report_type, 232 HID_REQ_GET_REPORT); 233 234 if (ret < 0) 235 goto out_free; 236 237 len = (ret < count) ? ret : count; 238 239 if (copy_to_user(buffer, buf, len)) { 240 ret = -EFAULT; 241 goto out_free; 242 } 243 244 ret = len; 245 246 out_free: 247 kfree(buf); 248 out: 249 return ret; 250 } 251 252 static unsigned int hidraw_poll(struct file *file, poll_table *wait) 253 { 254 struct hidraw_list *list = file->private_data; 255 256 poll_wait(file, &list->hidraw->wait, wait); 257 if (list->head != list->tail) 258 return POLLIN | POLLRDNORM; 259 if (!list->hidraw->exist) 260 return POLLERR | POLLHUP; 261 return 0; 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 mutex_lock(&minors_lock); 278 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) { 279 err = -ENODEV; 280 goto out_unlock; 281 } 282 283 dev = hidraw_table[minor]; 284 if (!dev->open++) { 285 err = hid_hw_power(dev->hid, PM_HINT_FULLON); 286 if (err < 0) { 287 dev->open--; 288 goto out_unlock; 289 } 290 291 err = hid_hw_open(dev->hid); 292 if (err < 0) { 293 hid_hw_power(dev->hid, PM_HINT_NORMAL); 294 dev->open--; 295 goto out_unlock; 296 } 297 } 298 299 list->hidraw = hidraw_table[minor]; 300 mutex_init(&list->read_mutex); 301 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags); 302 list_add_tail(&list->node, &hidraw_table[minor]->list); 303 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags); 304 file->private_data = list; 305 out_unlock: 306 mutex_unlock(&minors_lock); 307 out: 308 if (err < 0) 309 kfree(list); 310 return err; 311 312 } 313 314 static int hidraw_fasync(int fd, struct file *file, int on) 315 { 316 struct hidraw_list *list = file->private_data; 317 318 return fasync_helper(fd, file, on, &list->fasync); 319 } 320 321 static void drop_ref(struct hidraw *hidraw, int exists_bit) 322 { 323 if (exists_bit) { 324 hidraw->exist = 0; 325 if (hidraw->open) { 326 hid_hw_close(hidraw->hid); 327 wake_up_interruptible(&hidraw->wait); 328 } 329 device_destroy(hidraw_class, 330 MKDEV(hidraw_major, hidraw->minor)); 331 } else { 332 --hidraw->open; 333 } 334 if (!hidraw->open) { 335 if (!hidraw->exist) { 336 hidraw_table[hidraw->minor] = NULL; 337 kfree(hidraw); 338 } else { 339 /* close device for last reader */ 340 hid_hw_close(hidraw->hid); 341 hid_hw_power(hidraw->hid, PM_HINT_NORMAL); 342 } 343 } 344 } 345 346 static int hidraw_release(struct inode * inode, struct file * file) 347 { 348 unsigned int minor = iminor(inode); 349 struct hidraw_list *list = file->private_data; 350 unsigned long flags; 351 352 mutex_lock(&minors_lock); 353 354 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags); 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 mutex_unlock(&minors_lock); 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 mutex_lock(&minors_lock); 375 dev = hidraw_table[minor]; 376 if (!dev) { 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 /* Begin Read-only ioctls. */ 434 if (_IOC_DIR(cmd) != _IOC_READ) { 435 ret = -EINVAL; 436 break; 437 } 438 439 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) { 440 int len = strlen(hid->name) + 1; 441 if (len > _IOC_SIZE(cmd)) 442 len = _IOC_SIZE(cmd); 443 ret = copy_to_user(user_arg, hid->name, len) ? 444 -EFAULT : len; 445 break; 446 } 447 448 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) { 449 int len = strlen(hid->phys) + 1; 450 if (len > _IOC_SIZE(cmd)) 451 len = _IOC_SIZE(cmd); 452 ret = copy_to_user(user_arg, hid->phys, len) ? 453 -EFAULT : len; 454 break; 455 } 456 } 457 458 ret = -ENOTTY; 459 } 460 out: 461 mutex_unlock(&minors_lock); 462 return ret; 463 } 464 465 static const struct file_operations hidraw_ops = { 466 .owner = THIS_MODULE, 467 .read = hidraw_read, 468 .write = hidraw_write, 469 .poll = hidraw_poll, 470 .open = hidraw_open, 471 .release = hidraw_release, 472 .unlocked_ioctl = hidraw_ioctl, 473 .fasync = hidraw_fasync, 474 #ifdef CONFIG_COMPAT 475 .compat_ioctl = hidraw_ioctl, 476 #endif 477 .llseek = noop_llseek, 478 }; 479 480 int hidraw_report_event(struct hid_device *hid, u8 *data, int len) 481 { 482 struct hidraw *dev = hid->hidraw; 483 struct hidraw_list *list; 484 int ret = 0; 485 unsigned long flags; 486 487 spin_lock_irqsave(&dev->list_lock, flags); 488 list_for_each_entry(list, &dev->list, node) { 489 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1); 490 491 if (new_head == list->tail) 492 continue; 493 494 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) { 495 ret = -ENOMEM; 496 break; 497 } 498 list->buffer[list->head].len = len; 499 list->head = new_head; 500 kill_fasync(&list->fasync, SIGIO, POLL_IN); 501 } 502 spin_unlock_irqrestore(&dev->list_lock, flags); 503 504 wake_up_interruptible(&dev->wait); 505 return ret; 506 } 507 EXPORT_SYMBOL_GPL(hidraw_report_event); 508 509 int hidraw_connect(struct hid_device *hid) 510 { 511 int minor, result; 512 struct hidraw *dev; 513 514 /* we accept any HID device, all applications */ 515 516 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL); 517 if (!dev) 518 return -ENOMEM; 519 520 result = -EINVAL; 521 522 mutex_lock(&minors_lock); 523 524 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) { 525 if (hidraw_table[minor]) 526 continue; 527 hidraw_table[minor] = dev; 528 result = 0; 529 break; 530 } 531 532 if (result) { 533 mutex_unlock(&minors_lock); 534 kfree(dev); 535 goto out; 536 } 537 538 dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor), 539 NULL, "%s%d", "hidraw", minor); 540 541 if (IS_ERR(dev->dev)) { 542 hidraw_table[minor] = NULL; 543 mutex_unlock(&minors_lock); 544 result = PTR_ERR(dev->dev); 545 kfree(dev); 546 goto out; 547 } 548 549 init_waitqueue_head(&dev->wait); 550 spin_lock_init(&dev->list_lock); 551 INIT_LIST_HEAD(&dev->list); 552 553 dev->hid = hid; 554 dev->minor = minor; 555 556 dev->exist = 1; 557 hid->hidraw = dev; 558 559 mutex_unlock(&minors_lock); 560 out: 561 return result; 562 563 } 564 EXPORT_SYMBOL_GPL(hidraw_connect); 565 566 void hidraw_disconnect(struct hid_device *hid) 567 { 568 struct hidraw *hidraw = hid->hidraw; 569 570 mutex_lock(&minors_lock); 571 572 drop_ref(hidraw, 1); 573 574 mutex_unlock(&minors_lock); 575 } 576 EXPORT_SYMBOL_GPL(hidraw_disconnect); 577 578 int __init hidraw_init(void) 579 { 580 int result; 581 dev_t dev_id; 582 583 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR, 584 HIDRAW_MAX_DEVICES, "hidraw"); 585 if (result < 0) { 586 pr_warn("can't get major number\n"); 587 goto out; 588 } 589 590 hidraw_major = MAJOR(dev_id); 591 592 hidraw_class = class_create(THIS_MODULE, "hidraw"); 593 if (IS_ERR(hidraw_class)) { 594 result = PTR_ERR(hidraw_class); 595 goto error_cdev; 596 } 597 598 cdev_init(&hidraw_cdev, &hidraw_ops); 599 result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES); 600 if (result < 0) 601 goto error_class; 602 603 printk(KERN_INFO "hidraw: raw HID events driver (C) Jiri Kosina\n"); 604 out: 605 return result; 606 607 error_class: 608 class_destroy(hidraw_class); 609 error_cdev: 610 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 611 goto out; 612 } 613 614 void hidraw_exit(void) 615 { 616 dev_t dev_id = MKDEV(hidraw_major, 0); 617 618 cdev_del(&hidraw_cdev); 619 class_destroy(hidraw_class); 620 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 621 622 } 623