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