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                 kfree(list);
 263                 err = -ENODEV;
 264                 goto out_unlock;
 265         }
 266
 267         list->hidraw = hidraw_table[minor];
 268         mutex_init(&list->read_mutex);
 269         list_add_tail(&list->node, &hidraw_table[minor]->list);
 270         file->private_data = list;
 271
 272         dev = hidraw_table[minor];
 273         if (!dev->open++) {
 274                 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
 275                 if (err < 0)
 276                         goto out_unlock;
 277
 278                 err = hid_hw_open(dev->hid);
 279                 if (err < 0) {
 280                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 281                         dev->open--;
 282                 }
 283         }
 284
 285 out_unlock:
 286         mutex_unlock(&minors_lock);
 287 out:
 288         return err;
 289
 290 }
 291
 292 static int hidraw_release(struct inode * inode, struct file * file)
 293 {
 294         unsigned int minor = iminor(inode);
 295         struct hidraw *dev;
 296         struct hidraw_list *list = file->private_data;
 297         int ret;
 298
 299         mutex_lock(&minors_lock);
 300         if (!hidraw_table[minor]) {
 301                 ret = -ENODEV;
 302                 goto unlock;
 303         }
 304
 305         list_del(&list->node);
 306         dev = hidraw_table[minor];
 307         if (!--dev->open) {
 308                 if (list->hidraw->exist) {
 309                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 310                         hid_hw_close(dev->hid);
 311                 } else {
 312                         kfree(list->hidraw);
 313                 }
 314         }
 315         kfree(list);
 316         ret = 0;
 317 unlock:
 318         mutex_unlock(&minors_lock);
 319
 320         return ret;
 321 }
 322
 323 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 324                                                         unsigned long arg)
 325 {
 326         struct inode *inode = file->f_path.dentry->d_inode;
 327         unsigned int minor = iminor(inode);
 328         long ret = 0;
 329         struct hidraw *dev;
 330         void __user *user_arg = (void __user*) arg;
 331
 332         mutex_lock(&minors_lock);
 333         dev = hidraw_table[minor];
 334         if (!dev) {
 335                 ret = -ENODEV;
 336                 goto out;
 337         }
 338
 339         switch (cmd) {
 340                 case HIDIOCGRDESCSIZE:
 341                         if (put_user(dev->hid->rsize, (int __user *)arg))
 342                                 ret = -EFAULT;
 343                         break;
 344
 345                 case HIDIOCGRDESC:
 346                         {
 347                                 __u32 len;
 348
 349                                 if (get_user(len, (int __user *)arg))
 350                                         ret = -EFAULT;
 351                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 352                                         ret = -EINVAL;
 353                                 else if (copy_to_user(user_arg + offsetof(
 354                                         struct hidraw_report_descriptor,
 355                                         value[0]),
 356                                         dev->hid->rdesc,
 357                                         min(dev->hid->rsize, len)))
 358                                         ret = -EFAULT;
 359                                 break;
 360                         }
 361                 case HIDIOCGRAWINFO:
 362                         {
 363                                 struct hidraw_devinfo dinfo;
 364
 365                                 dinfo.bustype = dev->hid->bus;
 366                                 dinfo.vendor = dev->hid->vendor;
 367                                 dinfo.product = dev->hid->product;
 368                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 369                                         ret = -EFAULT;
 370                                 break;
 371                         }
 372                 default:
 373                         {
 374                                 struct hid_device *hid = dev->hid;
 375                                 if (_IOC_TYPE(cmd) != 'H') {
 376                                         ret = -EINVAL;
 377                                         break;
 378                                 }
 379
 380                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
 381                                         int len = _IOC_SIZE(cmd);
 382                                         ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
 383                                         break;
 384                                 }
 385                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
 386                                         int len = _IOC_SIZE(cmd);
 387                                         ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
 388                                         break;
 389                                 }
 390
 391                                 /* Begin Read-only ioctls. */
 392                                 if (_IOC_DIR(cmd) != _IOC_READ) {
 393                                         ret = -EINVAL;
 394                                         break;
 395                                 }
 396
 397                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 398                                         int len = strlen(hid->name) + 1;
 399                                         if (len > _IOC_SIZE(cmd))
 400                                                 len = _IOC_SIZE(cmd);
 401                                         ret = copy_to_user(user_arg, hid->name, len) ?
 402                                                 -EFAULT : len;
 403                                         break;
 404                                 }
 405
 406                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 407                                         int len = strlen(hid->phys) + 1;
 408                                         if (len > _IOC_SIZE(cmd))
 409                                                 len = _IOC_SIZE(cmd);
 410                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 411                                                 -EFAULT : len;
 412                                         break;
 413                                 }
 414                         }
 415
 416                 ret = -ENOTTY;
 417         }
 418 out:
 419         mutex_unlock(&minors_lock);
 420         return ret;
 421 }
 422
 423 static const struct file_operations hidraw_ops = {
 424         .owner =        THIS_MODULE,
 425         .read =         hidraw_read,
 426         .write =        hidraw_write,
 427         .poll =         hidraw_poll,
 428         .open =         hidraw_open,
 429         .release =      hidraw_release,
 430         .unlocked_ioctl = hidraw_ioctl,
 431 #ifdef CONFIG_COMPAT
 432         .compat_ioctl   = hidraw_ioctl,
 433 #endif
 434         .llseek =       noop_llseek,
 435 };
 436
 437 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 438 {
 439         struct hidraw *dev = hid->hidraw;
 440         struct hidraw_list *list;
 441
 442         list_for_each_entry(list, &dev->list, node) {
 443                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 444                 list->buffer[list->head].len = len;
 445                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 446                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 447         }
 448
 449         wake_up_interruptible(&dev->wait);
 450 }
 451 EXPORT_SYMBOL_GPL(hidraw_report_event);
 452
 453 int hidraw_connect(struct hid_device *hid)
 454 {
 455         int minor, result;
 456         struct hidraw *dev;
 457
 458         /* we accept any HID device, no matter the applications */
 459
 460         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 461         if (!dev)
 462                 return -ENOMEM;
 463
 464         result = -EINVAL;
 465
 466         mutex_lock(&minors_lock);
 467
 468         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 469                 if (hidraw_table[minor])
 470                         continue;
 471                 hidraw_table[minor] = dev;
 472                 result = 0;
 473                 break;
 474         }
 475
 476         if (result) {
 477                 mutex_unlock(&minors_lock);
 478                 kfree(dev);
 479                 goto out;
 480         }
 481
 482         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 483                                  NULL, "%s%d", "hidraw", minor);
 484
 485         if (IS_ERR(dev->dev)) {
 486                 hidraw_table[minor] = NULL;
 487                 mutex_unlock(&minors_lock);
 488                 result = PTR_ERR(dev->dev);
 489                 kfree(dev);
 490                 goto out;
 491         }
 492
 493         mutex_unlock(&minors_lock);
 494         init_waitqueue_head(&dev->wait);
 495         INIT_LIST_HEAD(&dev->list);
 496
 497         dev->hid = hid;
 498         dev->minor = minor;
 499
 500         dev->exist = 1;
 501         hid->hidraw = dev;
 502
 503 out:
 504         return result;
 505
 506 }
 507 EXPORT_SYMBOL_GPL(hidraw_connect);
 508
 509 void hidraw_disconnect(struct hid_device *hid)
 510 {
 511         struct hidraw *hidraw = hid->hidraw;
 512
 513         hidraw->exist = 0;
 514
 515         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 516
 517         mutex_lock(&minors_lock);
 518         hidraw_table[hidraw->minor] = NULL;
 519         mutex_unlock(&minors_lock);
 520
 521         if (hidraw->open) {
 522                 hid_hw_close(hid);
 523                 wake_up_interruptible(&hidraw->wait);
 524         } else {
 525                 kfree(hidraw);
 526         }
 527 }
 528 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 529
 530 int __init hidraw_init(void)
 531 {
 532         int result;
 533         dev_t dev_id;
 534
 535         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 536                         HIDRAW_MAX_DEVICES, "hidraw");
 537
 538         hidraw_major = MAJOR(dev_id);
 539
 540         if (result < 0) {
 541                 pr_warn("can't get major number\n");
 542                 result = 0;
 543                 goto out;
 544         }
 545
 546         hidraw_class = class_create(THIS_MODULE, "hidraw");
 547         if (IS_ERR(hidraw_class)) {
 548                 result = PTR_ERR(hidraw_class);
 549                 unregister_chrdev(hidraw_major, "hidraw");
 550                 goto out;
 551         }
 552
 553         cdev_init(&hidraw_cdev, &hidraw_ops);
 554         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 555 out:
 556         return result;
 557 }
 558
 559 void hidraw_exit(void)
 560 {
 561         dev_t dev_id = MKDEV(hidraw_major, 0);
 562
 563         cdev_del(&hidraw_cdev);
 564         class_destroy(hidraw_class);
 565         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 566
 567 }