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