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