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.h> 37 38 #include <linux/hidraw.h> 39 40 static int hidraw_major; 41 static struct cdev hidraw_cdev; 42 static struct class *hidraw_class; 43 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES]; 44 static DEFINE_MUTEX(minors_lock); 45 46 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos) 47 { 48 struct hidraw_list *list = file->private_data; 49 int ret = 0, len; 50 DECLARE_WAITQUEUE(wait, current); 51 52 mutex_lock(&list->read_mutex); 53 54 while (ret == 0) { 55 if (list->head == list->tail) { 56 add_wait_queue(&list->hidraw->wait, &wait); 57 set_current_state(TASK_INTERRUPTIBLE); 58 59 while (list->head == list->tail) { 60 if (signal_pending(current)) { 61 ret = -ERESTARTSYS; 62 break; 63 } 64 if (!list->hidraw->exist) { 65 ret = -EIO; 66 break; 67 } 68 if (file->f_flags & O_NONBLOCK) { 69 ret = -EAGAIN; 70 break; 71 } 72 73 /* allow O_NONBLOCK to work well from other threads */ 74 mutex_unlock(&list->read_mutex); 75 schedule(); 76 mutex_lock(&list->read_mutex); 77 set_current_state(TASK_INTERRUPTIBLE); 78 } 79 80 set_current_state(TASK_RUNNING); 81 remove_wait_queue(&list->hidraw->wait, &wait); 82 } 83 84 if (ret) 85 goto out; 86 87 len = list->buffer[list->tail].len > count ? 88 count : list->buffer[list->tail].len; 89 90 if (list->buffer[list->tail].value) { 91 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) { 92 ret = -EFAULT; 93 goto out; 94 } 95 ret = len; 96 } 97 98 kfree(list->buffer[list->tail].value); 99 list->buffer[list->tail].value = NULL; 100 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1); 101 } 102 out: 103 mutex_unlock(&list->read_mutex); 104 return ret; 105 } 106 107 /* 108 * The first byte of the report buffer is expected to be a report number. 109 * 110 * This function is to be called with the minors_lock mutex held. 111 */ 112 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type) 113 { 114 unsigned int minor = iminor(file_inode(file)); 115 struct hid_device *dev; 116 __u8 *buf; 117 int ret = 0; 118 119 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) { 120 ret = -ENODEV; 121 goto out; 122 } 123 124 dev = hidraw_table[minor]->hid; 125 126 if (!dev->hid_output_raw_report) { 127 ret = -ENODEV; 128 goto out; 129 } 130 131 if (count > HID_MAX_BUFFER_SIZE) { 132 hid_warn(dev, "pid %d passed too large report\n", 133 task_pid_nr(current)); 134 ret = -EINVAL; 135 goto out; 136 } 137 138 if (count < 2) { 139 hid_warn(dev, "pid %d passed too short report\n", 140 task_pid_nr(current)); 141 ret = -EINVAL; 142 goto out; 143 } 144 145 buf = kmalloc(count * sizeof(__u8), GFP_KERNEL); 146 if (!buf) { 147 ret = -ENOMEM; 148 goto out; 149 } 150 151 if (copy_from_user(buf, buffer, count)) { 152 ret = -EFAULT; 153 goto out_free; 154 } 155 156 ret = dev->hid_output_raw_report(dev, buf, count, report_type); 157 out_free: 158 kfree(buf); 159 out: 160 return ret; 161 } 162 163 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) 164 { 165 ssize_t ret; 166 mutex_lock(&minors_lock); 167 ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT); 168 mutex_unlock(&minors_lock); 169 return ret; 170 } 171 172 173 /* 174 * This function performs a Get_Report transfer over the control endpoint 175 * per section 7.2.1 of the HID specification, version 1.1. The first byte 176 * of buffer is the report number to request, or 0x0 if the defice does not 177 * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT 178 * or HID_INPUT_REPORT. 179 * 180 * This function is to be called with the minors_lock mutex held. 181 */ 182 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type) 183 { 184 unsigned int minor = iminor(file_inode(file)); 185 struct hid_device *dev; 186 __u8 *buf; 187 int ret = 0, len; 188 unsigned char report_number; 189 190 dev = hidraw_table[minor]->hid; 191 192 if (!dev->hid_get_raw_report) { 193 ret = -ENODEV; 194 goto out; 195 } 196 197 if (count > HID_MAX_BUFFER_SIZE) { 198 printk(KERN_WARNING "hidraw: pid %d passed too large report\n", 199 task_pid_nr(current)); 200 ret = -EINVAL; 201 goto out; 202 } 203 204 if (count < 2) { 205 printk(KERN_WARNING "hidraw: pid %d passed too short report\n", 206 task_pid_nr(current)); 207 ret = -EINVAL; 208 goto out; 209 } 210 211 buf = kmalloc(count * sizeof(__u8), GFP_KERNEL); 212 if (!buf) { 213 ret = -ENOMEM; 214 goto out; 215 } 216 217 /* 218 * Read the first byte from the user. This is the report number, 219 * which is passed to dev->hid_get_raw_report(). 220 */ 221 if (copy_from_user(&report_number, buffer, 1)) { 222 ret = -EFAULT; 223 goto out_free; 224 } 225 226 ret = dev->hid_get_raw_report(dev, report_number, buf, count, report_type); 227 228 if (ret < 0) 229 goto out_free; 230 231 len = (ret < count) ? ret : count; 232 233 if (copy_to_user(buffer, buf, len)) { 234 ret = -EFAULT; 235 goto out_free; 236 } 237 238 ret = len; 239 240 out_free: 241 kfree(buf); 242 out: 243 return ret; 244 } 245 246 static unsigned int hidraw_poll(struct file *file, poll_table *wait) 247 { 248 struct hidraw_list *list = file->private_data; 249 250 poll_wait(file, &list->hidraw->wait, wait); 251 if (list->head != list->tail) 252 return POLLIN | POLLRDNORM; 253 if (!list->hidraw->exist) 254 return POLLERR | POLLHUP; 255 return 0; 256 } 257 258 static int hidraw_open(struct inode *inode, struct file *file) 259 { 260 unsigned int minor = iminor(inode); 261 struct hidraw *dev; 262 struct hidraw_list *list; 263 unsigned long flags; 264 int err = 0; 265 266 if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) { 267 err = -ENOMEM; 268 goto out; 269 } 270 271 mutex_lock(&minors_lock); 272 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) { 273 err = -ENODEV; 274 goto out_unlock; 275 } 276 277 dev = hidraw_table[minor]; 278 if (!dev->open++) { 279 err = hid_hw_power(dev->hid, PM_HINT_FULLON); 280 if (err < 0) { 281 dev->open--; 282 goto out_unlock; 283 } 284 285 err = hid_hw_open(dev->hid); 286 if (err < 0) { 287 hid_hw_power(dev->hid, PM_HINT_NORMAL); 288 dev->open--; 289 goto out_unlock; 290 } 291 } 292 293 list->hidraw = hidraw_table[minor]; 294 mutex_init(&list->read_mutex); 295 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags); 296 list_add_tail(&list->node, &hidraw_table[minor]->list); 297 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags); 298 file->private_data = list; 299 out_unlock: 300 mutex_unlock(&minors_lock); 301 out: 302 if (err < 0) 303 kfree(list); 304 return err; 305 306 } 307 308 static int hidraw_fasync(int fd, struct file *file, int on) 309 { 310 struct hidraw_list *list = file->private_data; 311 312 return fasync_helper(fd, file, on, &list->fasync); 313 } 314 315 static void drop_ref(struct hidraw *hidraw, int exists_bit) 316 { 317 if (exists_bit) { 318 hidraw->exist = 0; 319 if (hidraw->open) { 320 hid_hw_close(hidraw->hid); 321 wake_up_interruptible(&hidraw->wait); 322 } 323 } else { 324 --hidraw->open; 325 } 326 if (!hidraw->open) { 327 if (!hidraw->exist) { 328 device_destroy(hidraw_class, 329 MKDEV(hidraw_major, hidraw->minor)); 330 hidraw_table[hidraw->minor] = NULL; 331 kfree(hidraw); 332 } else { 333 /* close device for last reader */ 334 hid_hw_power(hidraw->hid, PM_HINT_NORMAL); 335 hid_hw_close(hidraw->hid); 336 } 337 } 338 } 339 340 static int hidraw_release(struct inode * inode, struct file * file) 341 { 342 unsigned int minor = iminor(inode); 343 struct hidraw_list *list = file->private_data; 344 unsigned long flags; 345 346 mutex_lock(&minors_lock); 347 348 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags); 349 list_del(&list->node); 350 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags); 351 kfree(list); 352 353 drop_ref(hidraw_table[minor], 0); 354 355 mutex_unlock(&minors_lock); 356 return 0; 357 } 358 359 static long hidraw_ioctl(struct file *file, unsigned int cmd, 360 unsigned long arg) 361 { 362 struct inode *inode = file_inode(file); 363 unsigned int minor = iminor(inode); 364 long ret = 0; 365 struct hidraw *dev; 366 void __user *user_arg = (void __user*) arg; 367 368 mutex_lock(&minors_lock); 369 dev = hidraw_table[minor]; 370 if (!dev) { 371 ret = -ENODEV; 372 goto out; 373 } 374 375 switch (cmd) { 376 case HIDIOCGRDESCSIZE: 377 if (put_user(dev->hid->rsize, (int __user *)arg)) 378 ret = -EFAULT; 379 break; 380 381 case HIDIOCGRDESC: 382 { 383 __u32 len; 384 385 if (get_user(len, (int __user *)arg)) 386 ret = -EFAULT; 387 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1) 388 ret = -EINVAL; 389 else if (copy_to_user(user_arg + offsetof( 390 struct hidraw_report_descriptor, 391 value[0]), 392 dev->hid->rdesc, 393 min(dev->hid->rsize, len))) 394 ret = -EFAULT; 395 break; 396 } 397 case HIDIOCGRAWINFO: 398 { 399 struct hidraw_devinfo dinfo; 400 401 dinfo.bustype = dev->hid->bus; 402 dinfo.vendor = dev->hid->vendor; 403 dinfo.product = dev->hid->product; 404 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo))) 405 ret = -EFAULT; 406 break; 407 } 408 default: 409 { 410 struct hid_device *hid = dev->hid; 411 if (_IOC_TYPE(cmd) != 'H') { 412 ret = -EINVAL; 413 break; 414 } 415 416 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) { 417 int len = _IOC_SIZE(cmd); 418 ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT); 419 break; 420 } 421 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) { 422 int len = _IOC_SIZE(cmd); 423 ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT); 424 break; 425 } 426 427 /* Begin Read-only ioctls. */ 428 if (_IOC_DIR(cmd) != _IOC_READ) { 429 ret = -EINVAL; 430 break; 431 } 432 433 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) { 434 int len = strlen(hid->name) + 1; 435 if (len > _IOC_SIZE(cmd)) 436 len = _IOC_SIZE(cmd); 437 ret = copy_to_user(user_arg, hid->name, len) ? 438 -EFAULT : len; 439 break; 440 } 441 442 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) { 443 int len = strlen(hid->phys) + 1; 444 if (len > _IOC_SIZE(cmd)) 445 len = _IOC_SIZE(cmd); 446 ret = copy_to_user(user_arg, hid->phys, len) ? 447 -EFAULT : len; 448 break; 449 } 450 } 451 452 ret = -ENOTTY; 453 } 454 out: 455 mutex_unlock(&minors_lock); 456 return ret; 457 } 458 459 static const struct file_operations hidraw_ops = { 460 .owner = THIS_MODULE, 461 .read = hidraw_read, 462 .write = hidraw_write, 463 .poll = hidraw_poll, 464 .open = hidraw_open, 465 .release = hidraw_release, 466 .unlocked_ioctl = hidraw_ioctl, 467 .fasync = hidraw_fasync, 468 #ifdef CONFIG_COMPAT 469 .compat_ioctl = hidraw_ioctl, 470 #endif 471 .llseek = noop_llseek, 472 }; 473 474 int hidraw_report_event(struct hid_device *hid, u8 *data, int len) 475 { 476 struct hidraw *dev = hid->hidraw; 477 struct hidraw_list *list; 478 int ret = 0; 479 unsigned long flags; 480 481 spin_lock_irqsave(&dev->list_lock, flags); 482 list_for_each_entry(list, &dev->list, node) { 483 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1); 484 485 if (new_head == list->tail) 486 continue; 487 488 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) { 489 ret = -ENOMEM; 490 break; 491 } 492 list->buffer[list->head].len = len; 493 list->head = new_head; 494 kill_fasync(&list->fasync, SIGIO, POLL_IN); 495 } 496 spin_unlock_irqrestore(&dev->list_lock, flags); 497 498 wake_up_interruptible(&dev->wait); 499 return ret; 500 } 501 EXPORT_SYMBOL_GPL(hidraw_report_event); 502 503 int hidraw_connect(struct hid_device *hid) 504 { 505 int minor, result; 506 struct hidraw *dev; 507 508 /* we accept any HID device, all applications */ 509 510 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL); 511 if (!dev) 512 return -ENOMEM; 513 514 result = -EINVAL; 515 516 mutex_lock(&minors_lock); 517 518 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) { 519 if (hidraw_table[minor]) 520 continue; 521 hidraw_table[minor] = dev; 522 result = 0; 523 break; 524 } 525 526 if (result) { 527 mutex_unlock(&minors_lock); 528 kfree(dev); 529 goto out; 530 } 531 532 dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor), 533 NULL, "%s%d", "hidraw", minor); 534 535 if (IS_ERR(dev->dev)) { 536 hidraw_table[minor] = NULL; 537 mutex_unlock(&minors_lock); 538 result = PTR_ERR(dev->dev); 539 kfree(dev); 540 goto out; 541 } 542 543 init_waitqueue_head(&dev->wait); 544 spin_lock_init(&dev->list_lock); 545 INIT_LIST_HEAD(&dev->list); 546 547 dev->hid = hid; 548 dev->minor = minor; 549 550 dev->exist = 1; 551 hid->hidraw = dev; 552 553 mutex_unlock(&minors_lock); 554 out: 555 return result; 556 557 } 558 EXPORT_SYMBOL_GPL(hidraw_connect); 559 560 void hidraw_disconnect(struct hid_device *hid) 561 { 562 struct hidraw *hidraw = hid->hidraw; 563 564 mutex_lock(&minors_lock); 565 566 drop_ref(hidraw, 1); 567 568 mutex_unlock(&minors_lock); 569 } 570 EXPORT_SYMBOL_GPL(hidraw_disconnect); 571 572 int __init hidraw_init(void) 573 { 574 int result; 575 dev_t dev_id; 576 577 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR, 578 HIDRAW_MAX_DEVICES, "hidraw"); 579 580 hidraw_major = MAJOR(dev_id); 581 582 if (result < 0) { 583 pr_warn("can't get major number\n"); 584 goto out; 585 } 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 printk(KERN_INFO "hidraw: 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