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 (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
  91                         ret = -EFAULT;
  92                         goto out;
  93                 }
  94                 ret = len;
  95
  96                 kfree(list->buffer[list->tail].value);
  97                 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
  98         }
  99 out:
 100         mutex_unlock(&list->read_mutex);
 101         return ret;
 102 }
 103
 104 /* The first byte is expected to be a report number.
 105  * This function is to be called with the minors_lock mutex held */
 106 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
 107 {
 108         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 109         struct hid_device *dev;
 110         __u8 *buf;
 111         int ret = 0;
 112
 113         if (!hidraw_table[minor]) {
 114                 ret = -ENODEV;
 115                 goto out;
 116         }
 117
 118         dev = hidraw_table[minor]->hid;
 119
 120         if (!dev->hid_output_raw_report) {
 121                 ret = -ENODEV;
 122                 goto out;
 123         }
 124
 125         if (count > HID_MAX_BUFFER_SIZE) {
 126                 hid_warn(dev, "pid %d passed too large report\n",
 127                          task_pid_nr(current));
 128                 ret = -EINVAL;
 129                 goto out;
 130         }
 131
 132         if (count < 2) {
 133                 hid_warn(dev, "pid %d passed too short report\n",
 134                          task_pid_nr(current));
 135                 ret = -EINVAL;
 136                 goto out;
 137         }
 138
 139         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 140         if (!buf) {
 141                 ret = -ENOMEM;
 142                 goto out;
 143         }
 144
 145         if (copy_from_user(buf, buffer, count)) {
 146                 ret = -EFAULT;
 147                 goto out_free;
 148         }
 149
 150         ret = dev->hid_output_raw_report(dev, buf, count, report_type);
 151 out_free:
 152         kfree(buf);
 153 out:
 154         return ret;
 155 }
 156
 157 /* the first byte is expected to be a report number */
 158 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 159 {
 160         ssize_t ret;
 161         mutex_lock(&minors_lock);
 162         ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
 163         mutex_unlock(&minors_lock);
 164         return ret;
 165 }
 166
 167
 168 /* This function performs a Get_Report transfer over the control endpoint
 169  * per section 7.2.1 of the HID specification, version 1.1.  The first byte
 170  * of buffer is the report number to request, or 0x0 if the defice does not
 171  * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
 172  * or HID_INPUT_REPORT.  This function is to be called with the minors_lock
 173  *  mutex held. */
 174 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
 175 {
 176         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 177         struct hid_device *dev;
 178         __u8 *buf;
 179         int ret = 0, len;
 180         unsigned char report_number;
 181
 182         dev = hidraw_table[minor]->hid;
 183
 184         if (!dev->hid_get_raw_report) {
 185                 ret = -ENODEV;
 186                 goto out;
 187         }
 188
 189         if (count > HID_MAX_BUFFER_SIZE) {
 190                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 191                                 task_pid_nr(current));
 192                 ret = -EINVAL;
 193                 goto out;
 194         }
 195
 196         if (count < 2) {
 197                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 198                                 task_pid_nr(current));
 199                 ret = -EINVAL;
 200                 goto out;
 201         }
 202
 203         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 204         if (!buf) {
 205                 ret = -ENOMEM;
 206                 goto out;
 207         }
 208
 209         /* Read the first byte from the user. This is the report number,
 210          * which is passed to dev->hid_get_raw_report(). */
 211         if (copy_from_user(&report_number, buffer, 1)) {
 212                 ret = -EFAULT;
 213                 goto out_free;
 214         }
 215
 216         ret = dev->hid_get_raw_report(dev, report_number, buf, count, report_type);
 217
 218         if (ret < 0)
 219                 goto out_free;
 220
 221         len = (ret < count) ? ret : count;
 222
 223         if (copy_to_user(buffer, buf, len)) {
 224                 ret = -EFAULT;
 225                 goto out_free;
 226         }
 227
 228         ret = len;
 229
 230 out_free:
 231         kfree(buf);
 232 out:
 233         return ret;
 234 }
 235
 236 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 237 {
 238         struct hidraw_list *list = file->private_data;
 239
 240         poll_wait(file, &list->hidraw->wait, wait);
 241         if (list->head != list->tail)
 242                 return POLLIN | POLLRDNORM;
 243         if (!list->hidraw->exist)
 244                 return POLLERR | POLLHUP;
 245         return 0;
 246 }
 247
 248 static int hidraw_open(struct inode *inode, struct file *file)
 249 {
 250         unsigned int minor = iminor(inode);
 251         struct hidraw *dev;
 252         struct hidraw_list *list;
 253         int err = 0;
 254
 255         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 256                 err = -ENOMEM;
 257                 goto out;
 258         }
 259
 260         mutex_lock(&minors_lock);
 261         if (!hidraw_table[minor]) {
 262                 err = -ENODEV;
 263                 goto out_unlock;
 264         }
 265
 266         list->hidraw = hidraw_table[minor];
 267         mutex_init(&list->read_mutex);
 268         list_add_tail(&list->node, &hidraw_table[minor]->list);
 269         file->private_data = list;
 270
 271         dev = hidraw_table[minor];
 272         if (!dev->open++) {
 273                 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
 274                 if (err < 0) {
 275                         dev->open--;
 276                         goto out_unlock;
 277                 }
 278
 279                 err = hid_hw_open(dev->hid);
 280                 if (err < 0) {
 281                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 282                         dev->open--;
 283                 }
 284         }
 285
 286 out_unlock:
 287         mutex_unlock(&minors_lock);
 288 out:
 289         if (err < 0)
 290                 kfree(list);
 291         return err;
 292
 293 }
 294
 295 static int hidraw_release(struct inode * inode, struct file * file)
 296 {
 297         unsigned int minor = iminor(inode);
 298         struct hidraw *dev;
 299         struct hidraw_list *list = file->private_data;
 300         int ret;
 301
 302         mutex_lock(&minors_lock);
 303         if (!hidraw_table[minor]) {
 304                 ret = -ENODEV;
 305                 goto unlock;
 306         }
 307
 308         list_del(&list->node);
 309         dev = hidraw_table[minor];
 310         if (!--dev->open) {
 311                 if (list->hidraw->exist) {
 312                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 313                         hid_hw_close(dev->hid);
 314                 } else {
 315                         kfree(list->hidraw);
 316                 }
 317         }
 318         kfree(list);
 319         ret = 0;
 320 unlock:
 321         mutex_unlock(&minors_lock);
 322
 323         return ret;
 324 }
 325
 326 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 327                                                         unsigned long arg)
 328 {
 329         struct inode *inode = file->f_path.dentry->d_inode;
 330         unsigned int minor = iminor(inode);
 331         long ret = 0;
 332         struct hidraw *dev;
 333         void __user *user_arg = (void __user*) arg;
 334
 335         mutex_lock(&minors_lock);
 336         dev = hidraw_table[minor];
 337         if (!dev) {
 338                 ret = -ENODEV;
 339                 goto out;
 340         }
 341
 342         switch (cmd) {
 343                 case HIDIOCGRDESCSIZE:
 344                         if (put_user(dev->hid->rsize, (int __user *)arg))
 345                                 ret = -EFAULT;
 346                         break;
 347
 348                 case HIDIOCGRDESC:
 349                         {
 350                                 __u32 len;
 351
 352                                 if (get_user(len, (int __user *)arg))
 353                                         ret = -EFAULT;
 354                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 355                                         ret = -EINVAL;
 356                                 else if (copy_to_user(user_arg + offsetof(
 357                                         struct hidraw_report_descriptor,
 358                                         value[0]),
 359                                         dev->hid->rdesc,
 360                                         min(dev->hid->rsize, len)))
 361                                         ret = -EFAULT;
 362                                 break;
 363                         }
 364                 case HIDIOCGRAWINFO:
 365                         {
 366                                 struct hidraw_devinfo dinfo;
 367
 368                                 dinfo.bustype = dev->hid->bus;
 369                                 dinfo.vendor = dev->hid->vendor;
 370                                 dinfo.product = dev->hid->product;
 371                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 372                                         ret = -EFAULT;
 373                                 break;
 374                         }
 375                 default:
 376                         {
 377                                 struct hid_device *hid = dev->hid;
 378                                 if (_IOC_TYPE(cmd) != 'H') {
 379                                         ret = -EINVAL;
 380                                         break;
 381                                 }
 382
 383                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
 384                                         int len = _IOC_SIZE(cmd);
 385                                         ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
 386                                         break;
 387                                 }
 388                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
 389                                         int len = _IOC_SIZE(cmd);
 390                                         ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
 391                                         break;
 392                                 }
 393
 394                                 /* Begin Read-only ioctls. */
 395                                 if (_IOC_DIR(cmd) != _IOC_READ) {
 396                                         ret = -EINVAL;
 397                                         break;
 398                                 }
 399
 400                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 401                                         int len = strlen(hid->name) + 1;
 402                                         if (len > _IOC_SIZE(cmd))
 403                                                 len = _IOC_SIZE(cmd);
 404                                         ret = copy_to_user(user_arg, hid->name, len) ?
 405                                                 -EFAULT : len;
 406                                         break;
 407                                 }
 408
 409                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 410                                         int len = strlen(hid->phys) + 1;
 411                                         if (len > _IOC_SIZE(cmd))
 412                                                 len = _IOC_SIZE(cmd);
 413                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 414                                                 -EFAULT : len;
 415                                         break;
 416                                 }
 417                         }
 418
 419                 ret = -ENOTTY;
 420         }
 421 out:
 422         mutex_unlock(&minors_lock);
 423         return ret;
 424 }
 425
 426 static const struct file_operations hidraw_ops = {
 427         .owner =        THIS_MODULE,
 428         .read =         hidraw_read,
 429         .write =        hidraw_write,
 430         .poll =         hidraw_poll,
 431         .open =         hidraw_open,
 432         .release =      hidraw_release,
 433         .unlocked_ioctl = hidraw_ioctl,
 434 #ifdef CONFIG_COMPAT
 435         .compat_ioctl   = hidraw_ioctl,
 436 #endif
 437         .llseek =       noop_llseek,
 438 };
 439
 440 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 441 {
 442         struct hidraw *dev = hid->hidraw;
 443         struct hidraw_list *list;
 444
 445         list_for_each_entry(list, &dev->list, node) {
 446                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 447                 list->buffer[list->head].len = len;
 448                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 449                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 450         }
 451
 452         wake_up_interruptible(&dev->wait);
 453 }
 454 EXPORT_SYMBOL_GPL(hidraw_report_event);
 455
 456 int hidraw_connect(struct hid_device *hid)
 457 {
 458         int minor, result;
 459         struct hidraw *dev;
 460
 461         /* we accept any HID device, no matter the applications */
 462
 463         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 464         if (!dev)
 465                 return -ENOMEM;
 466
 467         result = -EINVAL;
 468
 469         mutex_lock(&minors_lock);
 470
 471         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 472                 if (hidraw_table[minor])
 473                         continue;
 474                 hidraw_table[minor] = dev;
 475                 result = 0;
 476                 break;
 477         }
 478
 479         if (result) {
 480                 mutex_unlock(&minors_lock);
 481                 kfree(dev);
 482                 goto out;
 483         }
 484
 485         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 486                                  NULL, "%s%d", "hidraw", minor);
 487
 488         if (IS_ERR(dev->dev)) {
 489                 hidraw_table[minor] = NULL;
 490                 mutex_unlock(&minors_lock);
 491                 result = PTR_ERR(dev->dev);
 492                 kfree(dev);
 493                 goto out;
 494         }
 495
 496         mutex_unlock(&minors_lock);
 497         init_waitqueue_head(&dev->wait);
 498         INIT_LIST_HEAD(&dev->list);
 499
 500         dev->hid = hid;
 501         dev->minor = minor;
 502
 503         dev->exist = 1;
 504         hid->hidraw = dev;
 505
 506 out:
 507         return result;
 508
 509 }
 510 EXPORT_SYMBOL_GPL(hidraw_connect);
 511
 512 void hidraw_disconnect(struct hid_device *hid)
 513 {
 514         struct hidraw *hidraw = hid->hidraw;
 515
 516         mutex_lock(&minors_lock);
 517         hidraw->exist = 0;
 518
 519         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 520
 521         hidraw_table[hidraw->minor] = NULL;
 522
 523         if (hidraw->open) {
 524                 hid_hw_close(hid);
 525                 wake_up_interruptible(&hidraw->wait);
 526         } else {
 527                 kfree(hidraw);
 528         }
 529         mutex_unlock(&minors_lock);
 530 }
 531 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 532
 533 int __init hidraw_init(void)
 534 {
 535         int result;
 536         dev_t dev_id;
 537
 538         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 539                         HIDRAW_MAX_DEVICES, "hidraw");
 540
 541         hidraw_major = MAJOR(dev_id);
 542
 543         if (result < 0) {
 544                 pr_warn("can't get major number\n");
 545                 result = 0;
 546                 goto out;
 547         }
 548
 549         hidraw_class = class_create(THIS_MODULE, "hidraw");
 550         if (IS_ERR(hidraw_class)) {
 551                 result = PTR_ERR(hidraw_class);
 552                 unregister_chrdev(hidraw_major, "hidraw");
 553                 goto out;
 554         }
 555
 556         cdev_init(&hidraw_cdev, &hidraw_ops);
 557         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 558 out:
 559         return result;
 560 }
 561
 562 void hidraw_exit(void)
 563 {
 564         dev_t dev_id = MKDEV(hidraw_major, 0);
 565
 566         cdev_del(&hidraw_cdev);
 567         class_destroy(hidraw_class);
 568         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 569
 570 }