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