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  */
  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 (file->f_flags & O_NONBLOCK) {
  61                                         ret = -EAGAIN;
  62                                         break;
  63                                 }
  64                                 if (signal_pending(current)) {
  65                                         ret = -ERESTARTSYS;
  66                                         break;
  67                                 }
  68                                 if (!list->hidraw->exist) {
  69                                         ret = -EIO;
  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->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
 100         }
 101 out:
 102         mutex_unlock(&list->read_mutex);
 103         return ret;
 104 }
 105
 106 /* The first byte is expected to be a report number.
 107  * This function is to be called with the minors_lock mutex held */
 108 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
 109 {
 110         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 111         struct hid_device *dev;
 112         __u8 *buf;
 113         int ret = 0;
 114
 115         if (!hidraw_table[minor]) {
 116                 ret = -ENODEV;
 117                 goto out;
 118         }
 119
 120         dev = hidraw_table[minor]->hid;
 121
 122         if (!dev->hid_output_raw_report) {
 123                 ret = -ENODEV;
 124                 goto out;
 125         }
 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 = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 142         if (!buf) {
 143                 ret = -ENOMEM;
 144                 goto out;
 145         }
 146
 147         if (copy_from_user(buf, buffer, count)) {
 148                 ret = -EFAULT;
 149                 goto out_free;
 150         }
 151
 152         ret = dev->hid_output_raw_report(dev, buf, count, report_type);
 153 out_free:
 154         kfree(buf);
 155 out:
 156         return ret;
 157 }
 158
 159 /* the first byte is expected to be a report number */
 160 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 161 {
 162         ssize_t ret;
 163         mutex_lock(&minors_lock);
 164         ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
 165         mutex_unlock(&minors_lock);
 166         return ret;
 167 }
 168
 169
 170 /* This function performs a Get_Report transfer over the control endpoint
 171  * per section 7.2.1 of the HID specification, version 1.1.  The first byte
 172  * of buffer is the report number to request, or 0x0 if the defice does not
 173  * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
 174  * or HID_INPUT_REPORT.  This function is to be called with the minors_lock
 175  *  mutex held. */
 176 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
 177 {
 178         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 179         struct hid_device *dev;
 180         __u8 *buf;
 181         int ret = 0, len;
 182         unsigned char report_number;
 183
 184         dev = hidraw_table[minor]->hid;
 185
 186         if (!dev->hid_get_raw_report) {
 187                 ret = -ENODEV;
 188                 goto out;
 189         }
 190
 191         if (count > HID_MAX_BUFFER_SIZE) {
 192                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 193                                 task_pid_nr(current));
 194                 ret = -EINVAL;
 195                 goto out;
 196         }
 197
 198         if (count < 2) {
 199                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 200                                 task_pid_nr(current));
 201                 ret = -EINVAL;
 202                 goto out;
 203         }
 204
 205         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 206         if (!buf) {
 207                 ret = -ENOMEM;
 208                 goto out;
 209         }
 210
 211         /* Read the first byte from the user. This is the report number,
 212          * which is passed to dev->hid_get_raw_report(). */
 213         if (copy_from_user(&report_number, buffer, 1)) {
 214                 ret = -EFAULT;
 215                 goto out_free;
 216         }
 217
 218         ret = dev->hid_get_raw_report(dev, report_number, buf, count, report_type);
 219
 220         if (ret < 0)
 221                 goto out_free;
 222
 223         len = (ret < count) ? ret : count;
 224
 225         if (copy_to_user(buffer, buf, len)) {
 226                 ret = -EFAULT;
 227                 goto out_free;
 228         }
 229
 230         ret = len;
 231
 232 out_free:
 233         kfree(buf);
 234 out:
 235         return ret;
 236 }
 237
 238 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 239 {
 240         struct hidraw_list *list = file->private_data;
 241
 242         poll_wait(file, &list->hidraw->wait, wait);
 243         if (list->head != list->tail)
 244                 return POLLIN | POLLRDNORM;
 245         if (!list->hidraw->exist)
 246                 return POLLERR | POLLHUP;
 247         return 0;
 248 }
 249
 250 static int hidraw_open(struct inode *inode, struct file *file)
 251 {
 252         unsigned int minor = iminor(inode);
 253         struct hidraw *dev;
 254         struct hidraw_list *list;
 255         int err = 0;
 256
 257         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 258                 err = -ENOMEM;
 259                 goto out;
 260         }
 261
 262         mutex_lock(&minors_lock);
 263         if (!hidraw_table[minor]) {
 264                 err = -ENODEV;
 265                 goto out_unlock;
 266         }
 267
 268         list->hidraw = hidraw_table[minor];
 269         mutex_init(&list->read_mutex);
 270         list_add_tail(&list->node, &hidraw_table[minor]->list);
 271         file->private_data = list;
 272
 273         dev = hidraw_table[minor];
 274         if (!dev->open++) {
 275                 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
 276                 if (err < 0) {
 277                         dev->open--;
 278                         goto out_unlock;
 279                 }
 280
 281                 err = hid_hw_open(dev->hid);
 282                 if (err < 0) {
 283                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 284                         dev->open--;
 285                 }
 286         }
 287
 288 out_unlock:
 289         mutex_unlock(&minors_lock);
 290 out:
 291         if (err < 0)
 292                 kfree(list);
 293         return err;
 294
 295 }
 296
 297 static int hidraw_release(struct inode * inode, struct file * file)
 298 {
 299         unsigned int minor = iminor(inode);
 300         struct hidraw *dev;
 301         struct hidraw_list *list = file->private_data;
 302         int ret;
 303
 304         mutex_lock(&minors_lock);
 305         if (!hidraw_table[minor]) {
 306                 ret = -ENODEV;
 307                 goto unlock;
 308         }
 309
 310         list_del(&list->node);
 311         dev = hidraw_table[minor];
 312         if (!--dev->open) {
 313                 if (list->hidraw->exist) {
 314                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 315                         hid_hw_close(dev->hid);
 316                 } else {
 317                         kfree(list->hidraw);
 318                 }
 319         }
 320         kfree(list);
 321         ret = 0;
 322 unlock:
 323         mutex_unlock(&minors_lock);
 324
 325         return ret;
 326 }
 327
 328 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 329                                                         unsigned long arg)
 330 {
 331         struct inode *inode = file->f_path.dentry->d_inode;
 332         unsigned int minor = iminor(inode);
 333         long ret = 0;
 334         struct hidraw *dev;
 335         void __user *user_arg = (void __user*) arg;
 336
 337         mutex_lock(&minors_lock);
 338         dev = hidraw_table[minor];
 339         if (!dev) {
 340                 ret = -ENODEV;
 341                 goto out;
 342         }
 343
 344         switch (cmd) {
 345                 case HIDIOCGRDESCSIZE:
 346                         if (put_user(dev->hid->rsize, (int __user *)arg))
 347                                 ret = -EFAULT;
 348                         break;
 349
 350                 case HIDIOCGRDESC:
 351                         {
 352                                 __u32 len;
 353
 354                                 if (get_user(len, (int __user *)arg))
 355                                         ret = -EFAULT;
 356                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 357                                         ret = -EINVAL;
 358                                 else if (copy_to_user(user_arg + offsetof(
 359                                         struct hidraw_report_descriptor,
 360                                         value[0]),
 361                                         dev->hid->rdesc,
 362                                         min(dev->hid->rsize, len)))
 363                                         ret = -EFAULT;
 364                                 break;
 365                         }
 366                 case HIDIOCGRAWINFO:
 367                         {
 368                                 struct hidraw_devinfo dinfo;
 369
 370                                 dinfo.bustype = dev->hid->bus;
 371                                 dinfo.vendor = dev->hid->vendor;
 372                                 dinfo.product = dev->hid->product;
 373                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 374                                         ret = -EFAULT;
 375                                 break;
 376                         }
 377                 default:
 378                         {
 379                                 struct hid_device *hid = dev->hid;
 380                                 if (_IOC_TYPE(cmd) != 'H') {
 381                                         ret = -EINVAL;
 382                                         break;
 383                                 }
 384
 385                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
 386                                         int len = _IOC_SIZE(cmd);
 387                                         ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
 388                                         break;
 389                                 }
 390                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
 391                                         int len = _IOC_SIZE(cmd);
 392                                         ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
 393                                         break;
 394                                 }
 395
 396                                 /* Begin Read-only ioctls. */
 397                                 if (_IOC_DIR(cmd) != _IOC_READ) {
 398                                         ret = -EINVAL;
 399                                         break;
 400                                 }
 401
 402                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 403                                         int len = strlen(hid->name) + 1;
 404                                         if (len > _IOC_SIZE(cmd))
 405                                                 len = _IOC_SIZE(cmd);
 406                                         ret = copy_to_user(user_arg, hid->name, len) ?
 407                                                 -EFAULT : len;
 408                                         break;
 409                                 }
 410
 411                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 412                                         int len = strlen(hid->phys) + 1;
 413                                         if (len > _IOC_SIZE(cmd))
 414                                                 len = _IOC_SIZE(cmd);
 415                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 416                                                 -EFAULT : len;
 417                                         break;
 418                                 }
 419                         }
 420
 421                 ret = -ENOTTY;
 422         }
 423 out:
 424         mutex_unlock(&minors_lock);
 425         return ret;
 426 }
 427
 428 static const struct file_operations hidraw_ops = {
 429         .owner =        THIS_MODULE,
 430         .read =         hidraw_read,
 431         .write =        hidraw_write,
 432         .poll =         hidraw_poll,
 433         .open =         hidraw_open,
 434         .release =      hidraw_release,
 435         .unlocked_ioctl = hidraw_ioctl,
 436 #ifdef CONFIG_COMPAT
 437         .compat_ioctl   = hidraw_ioctl,
 438 #endif
 439         .llseek =       noop_llseek,
 440 };
 441
 442 int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 443 {
 444         struct hidraw *dev = hid->hidraw;
 445         struct hidraw_list *list;
 446         int ret = 0;
 447
 448         list_for_each_entry(list, &dev->list, node) {
 449                 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
 450                         ret = -ENOMEM;
 451                         break;
 452                 }
 453                 list->buffer[list->head].len = len;
 454                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 455                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 456         }
 457
 458         wake_up_interruptible(&dev->wait);
 459         return ret;
 460 }
 461 EXPORT_SYMBOL_GPL(hidraw_report_event);
 462
 463 int hidraw_connect(struct hid_device *hid)
 464 {
 465         int minor, result;
 466         struct hidraw *dev;
 467
 468         /* we accept any HID device, no matter the applications */
 469
 470         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 471         if (!dev)
 472                 return -ENOMEM;
 473
 474         result = -EINVAL;
 475
 476         mutex_lock(&minors_lock);
 477
 478         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 479                 if (hidraw_table[minor])
 480                         continue;
 481                 hidraw_table[minor] = dev;
 482                 result = 0;
 483                 break;
 484         }
 485
 486         if (result) {
 487                 mutex_unlock(&minors_lock);
 488                 kfree(dev);
 489                 goto out;
 490         }
 491
 492         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 493                                  NULL, "%s%d", "hidraw", minor);
 494
 495         if (IS_ERR(dev->dev)) {
 496                 hidraw_table[minor] = NULL;
 497                 mutex_unlock(&minors_lock);
 498                 result = PTR_ERR(dev->dev);
 499                 kfree(dev);
 500                 goto out;
 501         }
 502
 503         mutex_unlock(&minors_lock);
 504         init_waitqueue_head(&dev->wait);
 505         INIT_LIST_HEAD(&dev->list);
 506
 507         dev->hid = hid;
 508         dev->minor = minor;
 509
 510         dev->exist = 1;
 511         hid->hidraw = dev;
 512
 513 out:
 514         return result;
 515
 516 }
 517 EXPORT_SYMBOL_GPL(hidraw_connect);
 518
 519 void hidraw_disconnect(struct hid_device *hid)
 520 {
 521         struct hidraw *hidraw = hid->hidraw;
 522
 523         mutex_lock(&minors_lock);
 524         hidraw->exist = 0;
 525
 526         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 527
 528         hidraw_table[hidraw->minor] = NULL;
 529
 530         if (hidraw->open) {
 531                 hid_hw_close(hid);
 532                 wake_up_interruptible(&hidraw->wait);
 533         } else {
 534                 kfree(hidraw);
 535         }
 536         mutex_unlock(&minors_lock);
 537 }
 538 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 539
 540 int __init hidraw_init(void)
 541 {
 542         int result;
 543         dev_t dev_id;
 544
 545         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 546                         HIDRAW_MAX_DEVICES, "hidraw");
 547
 548         hidraw_major = MAJOR(dev_id);
 549
 550         if (result < 0) {
 551                 pr_warn("can't get major number\n");
 552                 result = 0;
 553                 goto out;
 554         }
 555
 556         hidraw_class = class_create(THIS_MODULE, "hidraw");
 557         if (IS_ERR(hidraw_class)) {
 558                 result = PTR_ERR(hidraw_class);
 559                 unregister_chrdev(hidraw_major, "hidraw");
 560                 goto out;
 561         }
 562
 563         cdev_init(&hidraw_cdev, &hidraw_ops);
 564         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 565 out:
 566         return result;
 567 }
 568
 569 void hidraw_exit(void)
 570 {
 571         dev_t dev_id = MKDEV(hidraw_major, 0);
 572
 573         cdev_del(&hidraw_cdev);
 574         class_destroy(hidraw_class);
 575         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 576
 577 }