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