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         unsigned int mask = POLLOUT | POLLWRNORM; /* hidraw is always writable */
 266
 267         poll_wait(file, &list->hidraw->wait, wait);
 268         if (list->head != list->tail)
 269                 mask |= POLLIN | POLLRDNORM;
 270         if (!list->hidraw->exist)
 271                 mask |= POLLERR | POLLHUP;
 272         return mask;
 273 }
 274
 275 static int hidraw_open(struct inode *inode, struct file *file)
 276 {
 277         unsigned int minor = iminor(inode);
 278         struct hidraw *dev;
 279         struct hidraw_list *list;
 280         unsigned long flags;
 281         int err = 0;
 282
 283         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 284                 err = -ENOMEM;
 285                 goto out;
 286         }
 287
 288         mutex_lock(&minors_lock);
 289         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 290                 err = -ENODEV;
 291                 goto out_unlock;
 292         }
 293
 294         dev = hidraw_table[minor];
 295         if (!dev->open++) {
 296                 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
 297                 if (err < 0) {
 298                         dev->open--;
 299                         goto out_unlock;
 300                 }
 301
 302                 err = hid_hw_open(dev->hid);
 303                 if (err < 0) {
 304                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 305                         dev->open--;
 306                         goto out_unlock;
 307                 }
 308         }
 309
 310         list->hidraw = hidraw_table[minor];
 311         mutex_init(&list->read_mutex);
 312         spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
 313         list_add_tail(&list->node, &hidraw_table[minor]->list);
 314         spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
 315         file->private_data = list;
 316 out_unlock:
 317         mutex_unlock(&minors_lock);
 318 out:
 319         if (err < 0)
 320                 kfree(list);
 321         return err;
 322
 323 }
 324
 325 static int hidraw_fasync(int fd, struct file *file, int on)
 326 {
 327         struct hidraw_list *list = file->private_data;
 328
 329         return fasync_helper(fd, file, on, &list->fasync);
 330 }
 331
 332 static void drop_ref(struct hidraw *hidraw, int exists_bit)
 333 {
 334         if (exists_bit) {
 335                 hidraw->exist = 0;
 336                 if (hidraw->open) {
 337                         hid_hw_close(hidraw->hid);
 338                         wake_up_interruptible(&hidraw->wait);
 339                 }
 340                 device_destroy(hidraw_class,
 341                                MKDEV(hidraw_major, hidraw->minor));
 342         } else {
 343                 --hidraw->open;
 344         }
 345         if (!hidraw->open) {
 346                 if (!hidraw->exist) {
 347                         hidraw_table[hidraw->minor] = NULL;
 348                         kfree(hidraw);
 349                 } else {
 350                         /* close device for last reader */
 351                         hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
 352                         hid_hw_close(hidraw->hid);
 353                 }
 354         }
 355 }
 356
 357 static int hidraw_release(struct inode * inode, struct file * file)
 358 {
 359         unsigned int minor = iminor(inode);
 360         struct hidraw_list *list = file->private_data;
 361         unsigned long flags;
 362
 363         mutex_lock(&minors_lock);
 364
 365         spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
 366         list_del(&list->node);
 367         spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
 368         kfree(list);
 369
 370         drop_ref(hidraw_table[minor], 0);
 371
 372         mutex_unlock(&minors_lock);
 373         return 0;
 374 }
 375
 376 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 377                                                         unsigned long arg)
 378 {
 379         struct inode *inode = file_inode(file);
 380         unsigned int minor = iminor(inode);
 381         long ret = 0;
 382         struct hidraw *dev;
 383         void __user *user_arg = (void __user*) arg;
 384
 385         mutex_lock(&minors_lock);
 386         dev = hidraw_table[minor];
 387         if (!dev || !dev->exist) {
 388                 ret = -ENODEV;
 389                 goto out;
 390         }
 391
 392         switch (cmd) {
 393                 case HIDIOCGRDESCSIZE:
 394                         if (put_user(dev->hid->rsize, (int __user *)arg))
 395                                 ret = -EFAULT;
 396                         break;
 397
 398                 case HIDIOCGRDESC:
 399                         {
 400                                 __u32 len;
 401
 402                                 if (get_user(len, (int __user *)arg))
 403                                         ret = -EFAULT;
 404                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 405                                         ret = -EINVAL;
 406                                 else if (copy_to_user(user_arg + offsetof(
 407                                         struct hidraw_report_descriptor,
 408                                         value[0]),
 409                                         dev->hid->rdesc,
 410                                         min(dev->hid->rsize, len)))
 411                                         ret = -EFAULT;
 412                                 break;
 413                         }
 414                 case HIDIOCGRAWINFO:
 415                         {
 416                                 struct hidraw_devinfo dinfo;
 417
 418                                 dinfo.bustype = dev->hid->bus;
 419                                 dinfo.vendor = dev->hid->vendor;
 420                                 dinfo.product = dev->hid->product;
 421                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 422                                         ret = -EFAULT;
 423                                 break;
 424                         }
 425                 default:
 426                         {
 427                                 struct hid_device *hid = dev->hid;
 428                                 if (_IOC_TYPE(cmd) != 'H') {
 429                                         ret = -EINVAL;
 430                                         break;
 431                                 }
 432
 433                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
 434                                         int len = _IOC_SIZE(cmd);
 435                                         ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
 436                                         break;
 437                                 }
 438                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
 439                                         int len = _IOC_SIZE(cmd);
 440                                         ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
 441                                         break;
 442                                 }
 443
 444                                 /* Begin Read-only ioctls. */
 445                                 if (_IOC_DIR(cmd) != _IOC_READ) {
 446                                         ret = -EINVAL;
 447                                         break;
 448                                 }
 449
 450                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 451                                         int len = strlen(hid->name) + 1;
 452                                         if (len > _IOC_SIZE(cmd))
 453                                                 len = _IOC_SIZE(cmd);
 454                                         ret = copy_to_user(user_arg, hid->name, len) ?
 455                                                 -EFAULT : len;
 456                                         break;
 457                                 }
 458
 459                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 460                                         int len = strlen(hid->phys) + 1;
 461                                         if (len > _IOC_SIZE(cmd))
 462                                                 len = _IOC_SIZE(cmd);
 463                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 464                                                 -EFAULT : len;
 465                                         break;
 466                                 }
 467                         }
 468
 469                 ret = -ENOTTY;
 470         }
 471 out:
 472         mutex_unlock(&minors_lock);
 473         return ret;
 474 }
 475
 476 static const struct file_operations hidraw_ops = {
 477         .owner =        THIS_MODULE,
 478         .read =         hidraw_read,
 479         .write =        hidraw_write,
 480         .poll =         hidraw_poll,
 481         .open =         hidraw_open,
 482         .release =      hidraw_release,
 483         .unlocked_ioctl = hidraw_ioctl,
 484         .fasync =       hidraw_fasync,
 485 #ifdef CONFIG_COMPAT
 486         .compat_ioctl   = hidraw_ioctl,
 487 #endif
 488         .llseek =       noop_llseek,
 489 };
 490
 491 int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 492 {
 493         struct hidraw *dev = hid->hidraw;
 494         struct hidraw_list *list;
 495         int ret = 0;
 496         unsigned long flags;
 497
 498         spin_lock_irqsave(&dev->list_lock, flags);
 499         list_for_each_entry(list, &dev->list, node) {
 500                 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 501
 502                 if (new_head == list->tail)
 503                         continue;
 504
 505                 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
 506                         ret = -ENOMEM;
 507                         break;
 508                 }
 509                 list->buffer[list->head].len = len;
 510                 list->head = new_head;
 511                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 512         }
 513         spin_unlock_irqrestore(&dev->list_lock, flags);
 514
 515         wake_up_interruptible(&dev->wait);
 516         return ret;
 517 }
 518 EXPORT_SYMBOL_GPL(hidraw_report_event);
 519
 520 int hidraw_connect(struct hid_device *hid)
 521 {
 522         int minor, result;
 523         struct hidraw *dev;
 524
 525         /* we accept any HID device, all applications */
 526
 527         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 528         if (!dev)
 529                 return -ENOMEM;
 530
 531         result = -EINVAL;
 532
 533         mutex_lock(&minors_lock);
 534
 535         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 536                 if (hidraw_table[minor])
 537                         continue;
 538                 hidraw_table[minor] = dev;
 539                 result = 0;
 540                 break;
 541         }
 542
 543         if (result) {
 544                 mutex_unlock(&minors_lock);
 545                 kfree(dev);
 546                 goto out;
 547         }
 548
 549         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 550                                  NULL, "%s%d", "hidraw", minor);
 551
 552         if (IS_ERR(dev->dev)) {
 553                 hidraw_table[minor] = NULL;
 554                 mutex_unlock(&minors_lock);
 555                 result = PTR_ERR(dev->dev);
 556                 kfree(dev);
 557                 goto out;
 558         }
 559
 560         init_waitqueue_head(&dev->wait);
 561         spin_lock_init(&dev->list_lock);
 562         INIT_LIST_HEAD(&dev->list);
 563
 564         dev->hid = hid;
 565         dev->minor = minor;
 566
 567         dev->exist = 1;
 568         hid->hidraw = dev;
 569
 570         mutex_unlock(&minors_lock);
 571 out:
 572         return result;
 573
 574 }
 575 EXPORT_SYMBOL_GPL(hidraw_connect);
 576
 577 void hidraw_disconnect(struct hid_device *hid)
 578 {
 579         struct hidraw *hidraw = hid->hidraw;
 580
 581         mutex_lock(&minors_lock);
 582
 583         drop_ref(hidraw, 1);
 584
 585         mutex_unlock(&minors_lock);
 586 }
 587 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 588
 589 int __init hidraw_init(void)
 590 {
 591         int result;
 592         dev_t dev_id;
 593
 594         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 595                         HIDRAW_MAX_DEVICES, "hidraw");
 596
 597         hidraw_major = MAJOR(dev_id);
 598
 599         if (result < 0) {
 600                 pr_warn("can't get major number\n");
 601                 goto out;
 602         }
 603
 604         hidraw_class = class_create(THIS_MODULE, "hidraw");
 605         if (IS_ERR(hidraw_class)) {
 606                 result = PTR_ERR(hidraw_class);
 607                 goto error_cdev;
 608         }
 609
 610         cdev_init(&hidraw_cdev, &hidraw_ops);
 611         result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 612         if (result < 0)
 613                 goto error_class;
 614
 615         printk(KERN_INFO "hidraw: raw HID events driver (C) Jiri Kosina\n");
 616 out:
 617         return result;
 618
 619 error_class:
 620         class_destroy(hidraw_class);
 621 error_cdev:
 622         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 623         goto out;
 624 }
 625
 626 void hidraw_exit(void)
 627 {
 628         dev_t dev_id = MKDEV(hidraw_major, 0);
 629
 630         cdev_del(&hidraw_cdev);
 631         class_destroy(hidraw_class);
 632         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 633
 634 }