drivers/hid/hidraw.c

   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
 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 = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 142         if (!buf) {
 143                 ret = -ENOMEM;
 144                 goto out;
 145         }
 146
 147         if (copy_from_user(buf, buffer, count)) {
 148                 ret = -EFAULT;
 149                 goto out_free;
 150         }
 151
 152         if ((report_type == HID_OUTPUT_REPORT) &&
 153             !(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) {
 154                 ret = hid_hw_output_report(dev, buf, count);
 155                 /*
 156                  * compatibility with old implementation of USB-HID and I2C-HID:
 157                  * if the device does not support receiving output reports,
 158                  * on an interrupt endpoint, fallback to SET_REPORT HID command.
 159                  */
 160                 if (ret != -ENOSYS)
 161                         goto out_free;
 162         }
 163
 164         ret = hid_hw_raw_request(dev, buf[0], buf, count, report_type,
 165                                 HID_REQ_SET_REPORT);
 166
 167 out_free:
 168         kfree(buf);
 169 out:
 170         return ret;
 171 }
 172
 173 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 174 {
 175         ssize_t ret;
 176         mutex_lock(&minors_lock);
 177         ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
 178         mutex_unlock(&minors_lock);
 179         return ret;
 180 }
 181
 182
 183 /*
 184  * This function performs a Get_Report transfer over the control endpoint
 185  * per section 7.2.1 of the HID specification, version 1.1.  The first byte
 186  * of buffer is the report number to request, or 0x0 if the defice does not
 187  * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
 188  * or HID_INPUT_REPORT.
 189  *
 190  * This function is to be called with the minors_lock mutex held.
 191  */
 192 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
 193 {
 194         unsigned int minor = iminor(file_inode(file));
 195         struct hid_device *dev;
 196         __u8 *buf;
 197         int ret = 0, len;
 198         unsigned char report_number;
 199
 200         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 201                 ret = -ENODEV;
 202                 goto out;
 203         }
 204
 205         dev = hidraw_table[minor]->hid;
 206
 207         if (!dev->ll_driver->raw_request) {
 208                 ret = -ENODEV;
 209                 goto out;
 210         }
 211
 212         if (count > HID_MAX_BUFFER_SIZE) {
 213                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 214                                 task_pid_nr(current));
 215                 ret = -EINVAL;
 216                 goto out;
 217         }
 218
 219         if (count < 2) {
 220                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 221                                 task_pid_nr(current));
 222                 ret = -EINVAL;
 223                 goto out;
 224         }
 225
 226         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 227         if (!buf) {
 228                 ret = -ENOMEM;
 229                 goto out;
 230         }
 231
 232         /*
 233          * Read the first byte from the user. This is the report number,
 234          * which is passed to hid_hw_raw_request().
 235          */
 236         if (copy_from_user(&report_number, buffer, 1)) {
 237                 ret = -EFAULT;
 238                 goto out_free;
 239         }
 240
 241         ret = hid_hw_raw_request(dev, report_number, buf, count, report_type,
 242                                  HID_REQ_GET_REPORT);
 243
 244         if (ret < 0)
 245                 goto out_free;
 246
 247         len = (ret < count) ? ret : count;
 248
 249         if (copy_to_user(buffer, buf, len)) {
 250                 ret = -EFAULT;
 251                 goto out_free;
 252         }
 253
 254         ret = len;
 255
 256 out_free:
 257         kfree(buf);
 258 out:
 259         return ret;
 260 }
 261
 262 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 263 {
 264         struct hidraw_list *list = file->private_data;
 265
 266         poll_wait(file, &list->hidraw->wait, wait);
 267         if (list->head != list->tail)
 268                 return POLLIN | POLLRDNORM;
 269         if (!list->hidraw->exist)
 270                 return POLLERR | POLLHUP;
 271         return 0;
 272 }
 273
 274 static int hidraw_open(struct inode *inode, struct file *file)
 275 {
 276         unsigned int minor = iminor(inode);
 277         struct hidraw *dev;
 278         struct hidraw_list *list;
 279         unsigned long flags;
 280         int err = 0;
 281
 282         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 283                 err = -ENOMEM;
 284                 goto out;
 285         }
 286
 287         mutex_lock(&minors_lock);
 288         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 289                 err = -ENODEV;
 290                 goto out_unlock;
 291         }
 292
 293         dev = hidraw_table[minor];
 294         if (!dev->open++) {
 295                 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
 296                 if (err < 0) {
 297                         dev->open--;
 298                         goto out_unlock;
 299                 }
 300
 301                 err = hid_hw_open(dev->hid);
 302                 if (err < 0) {
 303                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 304                         dev->open--;
 305                         goto out_unlock;
 306                 }
 307         }
 308
 309         list->hidraw = hidraw_table[minor];
 310         mutex_init(&list->read_mutex);
 311         spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
 312         list_add_tail(&list->node, &hidraw_table[minor]->list);
 313         spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
 314         file->private_data = list;
 315 out_unlock:
 316         mutex_unlock(&minors_lock);
 317 out:
 318         if (err < 0)
 319                 kfree(list);
 320         return err;
 321
 322 }
 323
 324 static int hidraw_fasync(int fd, struct file *file, int on)
 325 {
 326         struct hidraw_list *list = file->private_data;
 327
 328         return fasync_helper(fd, file, on, &list->fasync);
 329 }
 330
 331 static void drop_ref(struct hidraw *hidraw, int exists_bit)
 332 {
 333         if (exists_bit) {
 334                 hidraw->exist = 0;
 335                 if (hidraw->open) {
 336                         hid_hw_close(hidraw->hid);
 337                         wake_up_interruptible(&hidraw->wait);
 338                 }
 339                 device_destroy(hidraw_class,
 340                                MKDEV(hidraw_major, hidraw->minor));
 341         } else {
 342                 --hidraw->open;
 343         }
 344         if (!hidraw->open) {
 345                 if (!hidraw->exist) {
 346                         hidraw_table[hidraw->minor] = NULL;
 347                         kfree(hidraw);
 348                 } else {
 349                         /* close device for last reader */
 350                         hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
 351                         hid_hw_close(hidraw->hid);
 352                 }
 353         }
 354 }
 355
 356 static int hidraw_release(struct inode * inode, struct file * file)
 357 {
 358         unsigned int minor = iminor(inode);
 359         struct hidraw_list *list = file->private_data;
 360         unsigned long flags;
 361
 362         mutex_lock(&minors_lock);
 363
 364         spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
 365         list_del(&list->node);
 366         spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
 367         kfree(list);
 368
 369         drop_ref(hidraw_table[minor], 0);
 370
 371         mutex_unlock(&minors_lock);
 372         return 0;
 373 }
 374
 375 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 376                                                         unsigned long arg)
 377 {
 378         struct inode *inode = file_inode(file);
 379         unsigned int minor = iminor(inode);
 380         long ret = 0;
 381         struct hidraw *dev;
 382         void __user *user_arg = (void __user*) arg;
 383
 384         mutex_lock(&minors_lock);
 385         dev = hidraw_table[minor];
 386         if (!dev) {
 387                 ret = -ENODEV;
 388                 goto out;
 389         }
 390
 391         switch (cmd) {
 392                 case HIDIOCGRDESCSIZE:
 393                         if (put_user(dev->hid->rsize, (int __user *)arg))
 394                                 ret = -EFAULT;
 395                         break;
 396
 397                 case HIDIOCGRDESC:
 398                         {
 399                                 __u32 len;
 400
 401                                 if (get_user(len, (int __user *)arg))
 402                                         ret = -EFAULT;
 403                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 404                                         ret = -EINVAL;
 405                                 else if (copy_to_user(user_arg + offsetof(
 406                                         struct hidraw_report_descriptor,
 407                                         value[0]),
 408                                         dev->hid->rdesc,
 409                                         min(dev->hid->rsize, len)))
 410                                         ret = -EFAULT;
 411                                 break;
 412                         }
 413                 case HIDIOCGRAWINFO:
 414                         {
 415                                 struct hidraw_devinfo dinfo;
 416
 417                                 dinfo.bustype = dev->hid->bus;
 418                                 dinfo.vendor = dev->hid->vendor;
 419                                 dinfo.product = dev->hid->product;
 420                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 421                                         ret = -EFAULT;
 422                                 break;
 423                         }
 424                 default:
 425                         {
 426                                 struct hid_device *hid = dev->hid;
 427                                 if (_IOC_TYPE(cmd) != 'H') {
 428                                         ret = -EINVAL;
 429                                         break;
 430                                 }
 431
 432                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
 433                                         int len = _IOC_SIZE(cmd);
 434                                         ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
 435                                         break;
 436                                 }
 437                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
 438                                         int len = _IOC_SIZE(cmd);
 439                                         ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
 440                                         break;
 441                                 }
 442
 443                                 /* Begin Read-only ioctls. */
 444                                 if (_IOC_DIR(cmd) != _IOC_READ) {
 445                                         ret = -EINVAL;
 446                                         break;
 447                                 }
 448
 449                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 450                                         int len = strlen(hid->name) + 1;
 451                                         if (len > _IOC_SIZE(cmd))
 452                                                 len = _IOC_SIZE(cmd);
 453                                         ret = copy_to_user(user_arg, hid->name, len) ?
 454                                                 -EFAULT : len;
 455                                         break;
 456                                 }
 457
 458                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 459                                         int len = strlen(hid->phys) + 1;
 460                                         if (len > _IOC_SIZE(cmd))
 461                                                 len = _IOC_SIZE(cmd);
 462                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 463                                                 -EFAULT : len;
 464                                         break;
 465                                 }
 466                         }
 467
 468                 ret = -ENOTTY;
 469         }
 470 out:
 471         mutex_unlock(&minors_lock);
 472         return ret;
 473 }
 474
 475 static const struct file_operations hidraw_ops = {
 476         .owner =        THIS_MODULE,
 477         .read =         hidraw_read,
 478         .write =        hidraw_write,
 479         .poll =         hidraw_poll,
 480         .open =         hidraw_open,
 481         .release =      hidraw_release,
 482         .unlocked_ioctl = hidraw_ioctl,
 483         .fasync =       hidraw_fasync,
 484 #ifdef CONFIG_COMPAT
 485         .compat_ioctl   = hidraw_ioctl,
 486 #endif
 487         .llseek =       noop_llseek,
 488 };
 489
 490 int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 491 {
 492         struct hidraw *dev = hid->hidraw;
 493         struct hidraw_list *list;
 494         int ret = 0;
 495         unsigned long flags;
 496
 497         spin_lock_irqsave(&dev->list_lock, flags);
 498         list_for_each_entry(list, &dev->list, node) {
 499                 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 500
 501                 if (new_head == list->tail)
 502                         continue;
 503
 504                 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
 505                         ret = -ENOMEM;
 506                         break;
 507                 }
 508                 list->buffer[list->head].len = len;
 509                 list->head = new_head;
 510                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 511         }
 512         spin_unlock_irqrestore(&dev->list_lock, flags);
 513
 514         wake_up_interruptible(&dev->wait);
 515         return ret;
 516 }
 517 EXPORT_SYMBOL_GPL(hidraw_report_event);
 518
 519 int hidraw_connect(struct hid_device *hid)
 520 {
 521         int minor, result;
 522         struct hidraw *dev;
 523
 524         /* we accept any HID device, all applications */
 525
 526         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 527         if (!dev)
 528                 return -ENOMEM;
 529
 530         result = -EINVAL;
 531
 532         mutex_lock(&minors_lock);
 533
 534         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 535                 if (hidraw_table[minor])
 536                         continue;
 537                 hidraw_table[minor] = dev;
 538                 result = 0;
 539                 break;
 540         }
 541
 542         if (result) {
 543                 mutex_unlock(&minors_lock);
 544                 kfree(dev);
 545                 goto out;
 546         }
 547
 548         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 549                                  NULL, "%s%d", "hidraw", minor);
 550
 551         if (IS_ERR(dev->dev)) {
 552                 hidraw_table[minor] = NULL;
 553                 mutex_unlock(&minors_lock);
 554                 result = PTR_ERR(dev->dev);
 555                 kfree(dev);
 556                 goto out;
 557         }
 558
 559         init_waitqueue_head(&dev->wait);
 560         spin_lock_init(&dev->list_lock);
 561         INIT_LIST_HEAD(&dev->list);
 562
 563         dev->hid = hid;
 564         dev->minor = minor;
 565
 566         dev->exist = 1;
 567         hid->hidraw = dev;
 568
 569         mutex_unlock(&minors_lock);
 570 out:
 571         return result;
 572
 573 }
 574 EXPORT_SYMBOL_GPL(hidraw_connect);
 575
 576 void hidraw_disconnect(struct hid_device *hid)
 577 {
 578         struct hidraw *hidraw = hid->hidraw;
 579
 580         mutex_lock(&minors_lock);
 581
 582         drop_ref(hidraw, 1);
 583
 584         mutex_unlock(&minors_lock);
 585 }
 586 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 587
 588 int __init hidraw_init(void)
 589 {
 590         int result;
 591         dev_t dev_id;
 592
 593         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 594                         HIDRAW_MAX_DEVICES, "hidraw");
 595
 596         hidraw_major = MAJOR(dev_id);
 597
 598         if (result < 0) {
 599                 pr_warn("can't get major number\n");
 600                 goto out;
 601         }
 602
 603         hidraw_class = class_create(THIS_MODULE, "hidraw");
 604         if (IS_ERR(hidraw_class)) {
 605                 result = PTR_ERR(hidraw_class);
 606                 goto error_cdev;
 607         }
 608
 609         cdev_init(&hidraw_cdev, &hidraw_ops);
 610         result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 611         if (result < 0)
 612                 goto error_class;
 613
 614         printk(KERN_INFO "hidraw: raw HID events driver (C) Jiri Kosina\n");
 615 out:
 616         return result;
 617
 618 error_class:
 619         class_destroy(hidraw_class);
 620 error_cdev:
 621         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 622         goto out;
 623 }
 624
 625 void hidraw_exit(void)
 626 {
 627         dev_t dev_id = MKDEV(hidraw_major, 0);
 628
 629         cdev_del(&hidraw_cdev);
 630         class_destroy(hidraw_class);
 631         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 632
 633 }