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