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 Jiri Kosina
  10  * Copyright (c) 2014-2015, NVIDIA CORPORATION.  All rights reserved.
  11  */
  12
  13 /*
  14  * This program is free software; you can redistribute it and/or modify it
  15  * under the terms and conditions of the GNU General Public License,
  16  * version 2, as published by the Free Software Foundation.
  17  *
  18  * You should have received a copy of the GNU General Public License along with
  19  * this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  24
  25 #include <linux/fs.h>
  26 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/kernel.h>
  29 #include <linux/init.h>
  30 #include <linux/cdev.h>
  31 #include <linux/poll.h>
  32 #include <linux/device.h>
  33 #include <linux/major.h>
  34 #include <linux/slab.h>
  35 #include <linux/hid.h>
  36 #include <linux/mutex.h>
  37 #include <linux/sched.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 /* The first byte is expected to be a report number.
 109  * This function is to be called with the minors_lock mutex held */
 110 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
 111 {
 112         unsigned int minor = iminor(file_inode(file));
 113         struct hid_device *dev;
 114         __u8 *buf;
 115         int ret = 0;
 116
 117         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 118                 ret = -ENODEV;
 119                 goto out;
 120         }
 121
 122         dev = hidraw_table[minor]->hid;
 123
 124         if (!dev->hid_output_raw_report) {
 125                 ret = -ENODEV;
 126                 goto out;
 127         }
 128
 129         if (count > HID_MAX_BUFFER_SIZE) {
 130                 hid_warn(dev, "pid %d passed too large report\n",
 131                          task_pid_nr(current));
 132                 ret = -EINVAL;
 133                 goto out;
 134         }
 135
 136         if (count < 2) {
 137                 hid_warn(dev, "pid %d passed too short report\n",
 138                          task_pid_nr(current));
 139                 ret = -EINVAL;
 140                 goto out;
 141         }
 142
 143         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 144         if (!buf) {
 145                 ret = -ENOMEM;
 146                 goto out;
 147         }
 148
 149         if (copy_from_user(buf, buffer, count)) {
 150                 ret = -EFAULT;
 151                 goto out_free;
 152         }
 153
 154         ret = dev->hid_output_raw_report(dev, buf, count, report_type);
 155 out_free:
 156         kfree(buf);
 157 out:
 158         return ret;
 159 }
 160
 161 /* the first byte is expected to be a report number */
 162 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 163 {
 164         ssize_t ret;
 165         mutex_lock(&minors_lock);
 166         ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
 167         mutex_unlock(&minors_lock);
 168         return ret;
 169 }
 170
 171
 172 /* This function performs a Get_Report transfer over the control endpoint
 173  * per section 7.2.1 of the HID specification, version 1.1.  The first byte
 174  * of buffer is the report number to request, or 0x0 if the defice does not
 175  * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
 176  * or HID_INPUT_REPORT.  This function is to be called with the minors_lock
 177  *  mutex held. */
 178 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
 179 {
 180         unsigned int minor = iminor(file_inode(file));
 181         struct hid_device *dev;
 182         __u8 *buf;
 183         int ret = 0, len;
 184         unsigned char report_number;
 185
 186         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 187                 ret = -ENODEV;
 188                 goto out;
 189         }
 190
 191         dev = hidraw_table[minor]->hid;
 192
 193         if (!dev->hid_get_raw_report) {
 194                 ret = -ENODEV;
 195                 goto out;
 196         }
 197
 198         if (count > HID_MAX_BUFFER_SIZE) {
 199                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 200                                 task_pid_nr(current));
 201                 ret = -EINVAL;
 202                 goto out;
 203         }
 204
 205         if (count < 2) {
 206                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 207                                 task_pid_nr(current));
 208                 ret = -EINVAL;
 209                 goto out;
 210         }
 211
 212         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 213         if (!buf) {
 214                 ret = -ENOMEM;
 215                 goto out;
 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         if (copy_from_user(&report_number, buffer, 1)) {
 221                 ret = -EFAULT;
 222                 goto out_free;
 223         }
 224
 225         ret = dev->hid_get_raw_report(dev, report_number, buf, count, report_type);
 226
 227         if (ret < 0)
 228                 goto out_free;
 229
 230         len = (ret < count) ? ret : count;
 231
 232         if (copy_to_user(buffer, buf, len)) {
 233                 ret = -EFAULT;
 234                 goto out_free;
 235         }
 236
 237         ret = len;
 238
 239 out_free:
 240         kfree(buf);
 241 out:
 242         return ret;
 243 }
 244
 245 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 246 {
 247         struct hidraw_list *list = file->private_data;
 248
 249         poll_wait(file, &list->hidraw->wait, wait);
 250         if (list->head != list->tail)
 251                 return POLLIN | POLLRDNORM;
 252         if (!list->hidraw->exist)
 253                 return POLLERR | POLLHUP;
 254         return 0;
 255 }
 256
 257 static int hidraw_open(struct inode *inode, struct file *file)
 258 {
 259         unsigned int minor = iminor(inode);
 260         struct hidraw *dev;
 261         struct hidraw_list *list;
 262         int err = 0;
 263
 264         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 265                 err = -ENOMEM;
 266                 goto out;
 267         }
 268
 269         mutex_lock(&minors_lock);
 270         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 271                 err = -ENODEV;
 272                 goto out_unlock;
 273         }
 274
 275         list->hidraw = hidraw_table[minor];
 276         mutex_init(&list->read_mutex);
 277         list_add_tail(&list->node, &hidraw_table[minor]->list);
 278         file->private_data = list;
 279
 280         dev = hidraw_table[minor];
 281         if (!dev->open++) {
 282                 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
 283                 if (err < 0) {
 284                         dev->open--;
 285                         goto out_unlock;
 286                 }
 287
 288                 err = hid_hw_open(dev->hid);
 289                 if (err < 0) {
 290                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 291                         dev->open--;
 292                 }
 293         }
 294
 295 out_unlock:
 296         mutex_unlock(&minors_lock);
 297 out:
 298         if (err < 0)
 299                 kfree(list);
 300         return err;
 301
 302 }
 303
 304 static int hidraw_fasync(int fd, struct file *file, int on)
 305 {
 306         struct hidraw_list *list = file->private_data;
 307
 308         return fasync_helper(fd, file, on, &list->fasync);
 309 }
 310
 311 static void drop_ref(struct hidraw *hidraw, int exists_bit)
 312 {
 313         if (exists_bit) {
 314                 hidraw->exist = 0;
 315                 if (hidraw->open) {
 316                         hid_hw_close(hidraw->hid);
 317                         wake_up_interruptible(&hidraw->wait);
 318                 }
 319         } else {
 320                 --hidraw->open;
 321         }
 322
 323         if (!hidraw->open) {
 324                 if (!hidraw->exist) {
 325                         device_destroy(hidraw_class,
 326                                 MKDEV(hidraw_major, hidraw->minor));
 327                         hidraw_table[hidraw->minor] = NULL;
 328                         kfree(hidraw);
 329                 } else {
 330                         /* close device for last reader */
 331                         hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
 332                         hid_hw_close(hidraw->hid);
 333                 }
 334         }
 335 }
 336
 337 static int hidraw_release(struct inode * inode, struct file * file)
 338 {
 339         unsigned int minor = iminor(inode);
 340         struct hidraw_list *list = file->private_data;
 341         int i;
 342
 343         mutex_lock(&minors_lock);
 344
 345         for (i = 0; i < HIDRAW_BUFFER_SIZE; i++) {
 346                 kfree(list->buffer[i].value);
 347         }
 348
 349         list_del(&list->node);
 350         kfree(list);
 351
 352         drop_ref(hidraw_table[minor], 0);
 353
 354         mutex_unlock(&minors_lock);
 355         return 0;
 356 }
 357
 358 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 359                                                         unsigned long arg)
 360 {
 361         struct inode *inode = file_inode(file);
 362         unsigned int minor = iminor(inode);
 363         long ret = 0;
 364         struct hidraw *dev;
 365         void __user *user_arg = (void __user*) arg;
 366
 367         mutex_lock(&minors_lock);
 368         dev = hidraw_table[minor];
 369         if (!dev) {
 370                 ret = -ENODEV;
 371                 goto out;
 372         }
 373
 374         switch (cmd) {
 375                 case HIDIOCGRDESCSIZE:
 376                         if (put_user(dev->hid->rsize, (int __user *)arg))
 377                                 ret = -EFAULT;
 378                         break;
 379
 380                 case HIDIOCGRDESC:
 381                         {
 382                                 __u32 len;
 383
 384                                 if (get_user(len, (int __user *)arg))
 385                                         ret = -EFAULT;
 386                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 387                                         ret = -EINVAL;
 388                                 else if (copy_to_user(user_arg + offsetof(
 389                                         struct hidraw_report_descriptor,
 390                                         value[0]),
 391                                         dev->hid->rdesc,
 392                                         min(dev->hid->rsize, len)))
 393                                         ret = -EFAULT;
 394                                 break;
 395                         }
 396                 case HIDIOCGRAWINFO:
 397                         {
 398                                 struct hidraw_devinfo dinfo;
 399
 400                                 dinfo.bustype = dev->hid->bus;
 401                                 dinfo.vendor = dev->hid->vendor;
 402                                 dinfo.product = dev->hid->product;
 403                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 404                                         ret = -EFAULT;
 405                                 break;
 406                         }
 407                 default:
 408                         {
 409                                 struct hid_device *hid = dev->hid;
 410                                 if (_IOC_TYPE(cmd) != 'H') {
 411                                         ret = -EINVAL;
 412                                         break;
 413                                 }
 414
 415                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
 416                                         int len = _IOC_SIZE(cmd);
 417                                         ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
 418                                         break;
 419                                 }
 420                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
 421                                         int len = _IOC_SIZE(cmd);
 422                                         ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
 423                                         break;
 424                                 }
 425
 426                                 /* Begin Read-only ioctls. */
 427                                 if (_IOC_DIR(cmd) != _IOC_READ) {
 428                                         ret = -EINVAL;
 429                                         break;
 430                                 }
 431
 432                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 433                                         int len = strlen(hid->name) + 1;
 434                                         if (len > _IOC_SIZE(cmd))
 435                                                 len = _IOC_SIZE(cmd);
 436                                         ret = copy_to_user(user_arg, hid->name, len) ?
 437                                                 -EFAULT : len;
 438                                         break;
 439                                 }
 440
 441                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 442                                         int len = strlen(hid->phys) + 1;
 443                                         if (len > _IOC_SIZE(cmd))
 444                                                 len = _IOC_SIZE(cmd);
 445                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 446                                                 -EFAULT : len;
 447                                         break;
 448                                 }
 449                         }
 450
 451                 ret = -ENOTTY;
 452         }
 453 out:
 454         mutex_unlock(&minors_lock);
 455         return ret;
 456 }
 457
 458 static const struct file_operations hidraw_ops = {
 459         .owner =        THIS_MODULE,
 460         .read =         hidraw_read,
 461         .write =        hidraw_write,
 462         .poll =         hidraw_poll,
 463         .open =         hidraw_open,
 464         .release =      hidraw_release,
 465         .unlocked_ioctl = hidraw_ioctl,
 466         .fasync =       hidraw_fasync,
 467 #ifdef CONFIG_COMPAT
 468         .compat_ioctl   = hidraw_ioctl,
 469 #endif
 470         .llseek =       noop_llseek,
 471 };
 472
 473 int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 474 {
 475         struct hidraw *dev = hid->hidraw;
 476         struct hidraw_list *list;
 477         int ret = 0;
 478
 479         list_for_each_entry(list, &dev->list, node) {
 480                 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 481
 482                 if (new_head == list->tail)
 483                         continue;
 484
 485                 kfree(list->buffer[list->head].value);
 486                 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
 487                         ret = -ENOMEM;
 488                         break;
 489                 }
 490                 list->buffer[list->head].len = len;
 491                 list->head = new_head;
 492                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 493         }
 494
 495         wake_up_interruptible(&dev->wait);
 496         return ret;
 497 }
 498 EXPORT_SYMBOL_GPL(hidraw_report_event);
 499
 500 int hidraw_connect(struct hid_device *hid)
 501 {
 502         int minor, result;
 503         struct hidraw *dev;
 504
 505         /* we accept any HID device, no matter the applications */
 506
 507         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 508         if (!dev)
 509                 return -ENOMEM;
 510
 511         result = -EINVAL;
 512
 513         mutex_lock(&minors_lock);
 514
 515         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 516                 if (hidraw_table[minor])
 517                         continue;
 518                 hidraw_table[minor] = dev;
 519                 result = 0;
 520                 break;
 521         }
 522
 523         if (result) {
 524                 mutex_unlock(&minors_lock);
 525                 kfree(dev);
 526                 goto out;
 527         }
 528
 529         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 530                                  NULL, "%s%d", "hidraw", minor);
 531
 532         if (IS_ERR(dev->dev)) {
 533                 hidraw_table[minor] = NULL;
 534                 mutex_unlock(&minors_lock);
 535                 result = PTR_ERR(dev->dev);
 536                 kfree(dev);
 537                 goto out;
 538         }
 539
 540         mutex_unlock(&minors_lock);
 541         init_waitqueue_head(&dev->wait);
 542         INIT_LIST_HEAD(&dev->list);
 543
 544         dev->hid = hid;
 545         dev->minor = minor;
 546
 547         dev->exist = 1;
 548         hid->hidraw = dev;
 549
 550 out:
 551         return result;
 552
 553 }
 554 EXPORT_SYMBOL_GPL(hidraw_connect);
 555
 556 void hidraw_disconnect(struct hid_device *hid)
 557 {
 558         struct hidraw *hidraw = hid->hidraw;
 559
 560         mutex_lock(&minors_lock);
 561
 562         drop_ref(hidraw, 1);
 563
 564         mutex_unlock(&minors_lock);
 565 }
 566 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 567
 568 int __init hidraw_init(void)
 569 {
 570         int result;
 571         dev_t dev_id;
 572
 573         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 574                         HIDRAW_MAX_DEVICES, "hidraw");
 575
 576         hidraw_major = MAJOR(dev_id);
 577
 578         if (result < 0) {
 579                 pr_warn("can't get major number\n");
 580                 goto out;
 581         }
 582
 583         hidraw_class = class_create(THIS_MODULE, "hidraw");
 584         if (IS_ERR(hidraw_class)) {
 585                 result = PTR_ERR(hidraw_class);
 586                 goto error_cdev;
 587         }
 588
 589         cdev_init(&hidraw_cdev, &hidraw_ops);
 590         result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 591         if (result < 0)
 592                 goto error_class;
 593
 594         printk(KERN_INFO "hidraw: raw HID events driver (C) Jiri Kosina\n");
 595 out:
 596         return result;
 597
 598 error_class:
 599         class_destroy(hidraw_class);
 600 error_cdev:
 601         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 602         goto out;
 603 }
 604
 605 void hidraw_exit(void)
 606 {
 607         dev_t dev_id = MKDEV(hidraw_major, 0);
 608
 609         cdev_del(&hidraw_cdev);
 610         class_destroy(hidraw_class);
 611         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 612
 613 }