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 (signal_pending(current)) {
  61                                         ret = -ERESTARTSYS;
  62                                         break;
  63                                 }
  64                                 if (!list->hidraw->exist) {
  65                                         ret = -EIO;
  66                                         break;
  67                                 }
  68                                 if (file->f_flags & O_NONBLOCK) {
  69                                         ret = -EAGAIN;
  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->buffer[list->tail].value = NULL;
 100                 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
 101         }
 102 out:
 103         mutex_unlock(&list->read_mutex);
 104         return ret;
 105 }
 106
 107 /* The first byte is expected to be a report number.
 108  * This function is to be called with the minors_lock mutex held */
 109 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
 110 {
 111         unsigned int minor = iminor(file_inode(file));
 112         struct hid_device *dev;
 113         __u8 *buf;
 114         int ret = 0;
 115
 116         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 117                 ret = -ENODEV;
 118                 goto out;
 119         }
 120
 121         dev = hidraw_table[minor]->hid;
 122
 123         if (!dev->hid_output_raw_report) {
 124                 ret = -ENODEV;
 125                 goto out;
 126         }
 127
 128         if (count > HID_MAX_BUFFER_SIZE) {
 129                 hid_warn(dev, "pid %d passed too large report\n",
 130                          task_pid_nr(current));
 131                 ret = -EINVAL;
 132                 goto out;
 133         }
 134
 135         if (count < 2) {
 136                 hid_warn(dev, "pid %d passed too short report\n",
 137                          task_pid_nr(current));
 138                 ret = -EINVAL;
 139                 goto out;
 140         }
 141
 142         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 143         if (!buf) {
 144                 ret = -ENOMEM;
 145                 goto out;
 146         }
 147
 148         if (copy_from_user(buf, buffer, count)) {
 149                 ret = -EFAULT;
 150                 goto out_free;
 151         }
 152
 153         ret = dev->hid_output_raw_report(dev, buf, count, report_type);
 154 out_free:
 155         kfree(buf);
 156 out:
 157         return ret;
 158 }
 159
 160 /* the first byte is expected to be a report number */
 161 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 162 {
 163         ssize_t ret;
 164         mutex_lock(&minors_lock);
 165         ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
 166         mutex_unlock(&minors_lock);
 167         return ret;
 168 }
 169
 170
 171 /* This function performs a Get_Report transfer over the control endpoint
 172  * per section 7.2.1 of the HID specification, version 1.1.  The first byte
 173  * of buffer is the report number to request, or 0x0 if the defice does not
 174  * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
 175  * or HID_INPUT_REPORT.  This function is to be called with the minors_lock
 176  *  mutex held. */
 177 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
 178 {
 179         unsigned int minor = iminor(file_inode(file));
 180         struct hid_device *dev;
 181         __u8 *buf;
 182         int ret = 0, len;
 183         unsigned char report_number;
 184
 185         dev = hidraw_table[minor]->hid;
 186
 187         if (!dev->hid_get_raw_report) {
 188                 ret = -ENODEV;
 189                 goto out;
 190         }
 191
 192         if (count > HID_MAX_BUFFER_SIZE) {
 193                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 194                                 task_pid_nr(current));
 195                 ret = -EINVAL;
 196                 goto out;
 197         }
 198
 199         if (count < 2) {
 200                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 201                                 task_pid_nr(current));
 202                 ret = -EINVAL;
 203                 goto out;
 204         }
 205
 206         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 207         if (!buf) {
 208                 ret = -ENOMEM;
 209                 goto out;
 210         }
 211
 212         /* Read the first byte from the user. This is the report number,
 213          * which is passed to dev->hid_get_raw_report(). */
 214         if (copy_from_user(&report_number, buffer, 1)) {
 215                 ret = -EFAULT;
 216                 goto out_free;
 217         }
 218
 219         ret = dev->hid_get_raw_report(dev, report_number, buf, count, report_type);
 220
 221         if (ret < 0)
 222                 goto out_free;
 223
 224         len = (ret < count) ? ret : count;
 225
 226         if (copy_to_user(buffer, buf, len)) {
 227                 ret = -EFAULT;
 228                 goto out_free;
 229         }
 230
 231         ret = len;
 232
 233 out_free:
 234         kfree(buf);
 235 out:
 236         return ret;
 237 }
 238
 239 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 240 {
 241         struct hidraw_list *list = file->private_data;
 242
 243         poll_wait(file, &list->hidraw->wait, wait);
 244         if (list->head != list->tail)
 245                 return POLLIN | POLLRDNORM;
 246         if (!list->hidraw->exist)
 247                 return POLLERR | POLLHUP;
 248         return 0;
 249 }
 250
 251 static int hidraw_open(struct inode *inode, struct file *file)
 252 {
 253         unsigned int minor = iminor(inode);
 254         struct hidraw *dev;
 255         struct hidraw_list *list;
 256         int err = 0;
 257
 258         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 259                 err = -ENOMEM;
 260                 goto out;
 261         }
 262
 263         mutex_lock(&minors_lock);
 264         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 265                 err = -ENODEV;
 266                 goto out_unlock;
 267         }
 268
 269         list->hidraw = hidraw_table[minor];
 270         mutex_init(&list->read_mutex);
 271         list_add_tail(&list->node, &hidraw_table[minor]->list);
 272         file->private_data = list;
 273
 274         dev = hidraw_table[minor];
 275         if (!dev->open++) {
 276                 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
 277                 if (err < 0) {
 278                         dev->open--;
 279                         goto out_unlock;
 280                 }
 281
 282                 err = hid_hw_open(dev->hid);
 283                 if (err < 0) {
 284                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 285                         dev->open--;
 286                 }
 287         }
 288
 289 out_unlock:
 290         mutex_unlock(&minors_lock);
 291 out:
 292         if (err < 0)
 293                 kfree(list);
 294         return err;
 295
 296 }
 297
 298 static int hidraw_fasync(int fd, struct file *file, int on)
 299 {
 300         struct hidraw_list *list = file->private_data;
 301
 302         return fasync_helper(fd, file, on, &list->fasync);
 303 }
 304
 305 static void drop_ref(struct hidraw *hidraw, int exists_bit)
 306 {
 307         if (exists_bit) {
 308                 hid_hw_close(hidraw->hid);
 309                 hidraw->exist = 0;
 310                 if (hidraw->open)
 311                         wake_up_interruptible(&hidraw->wait);
 312         } else {
 313                 --hidraw->open;
 314         }
 315
 316         if (!hidraw->open && !hidraw->exist) {
 317                 device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 318                 hidraw_table[hidraw->minor] = NULL;
 319                 kfree(hidraw);
 320         }
 321 }
 322
 323 static int hidraw_release(struct inode * inode, struct file * file)
 324 {
 325         unsigned int minor = iminor(inode);
 326         struct hidraw_list *list = file->private_data;
 327
 328         mutex_lock(&minors_lock);
 329
 330         list_del(&list->node);
 331         kfree(list);
 332
 333         drop_ref(hidraw_table[minor], 0);
 334
 335         mutex_unlock(&minors_lock);
 336         return 0;
 337 }
 338
 339 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 340                                                         unsigned long arg)
 341 {
 342         struct inode *inode = file_inode(file);
 343         unsigned int minor = iminor(inode);
 344         long ret = 0;
 345         struct hidraw *dev;
 346         void __user *user_arg = (void __user*) arg;
 347
 348         mutex_lock(&minors_lock);
 349         dev = hidraw_table[minor];
 350         if (!dev) {
 351                 ret = -ENODEV;
 352                 goto out;
 353         }
 354
 355         switch (cmd) {
 356                 case HIDIOCGRDESCSIZE:
 357                         if (put_user(dev->hid->rsize, (int __user *)arg))
 358                                 ret = -EFAULT;
 359                         break;
 360
 361                 case HIDIOCGRDESC:
 362                         {
 363                                 __u32 len;
 364
 365                                 if (get_user(len, (int __user *)arg))
 366                                         ret = -EFAULT;
 367                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 368                                         ret = -EINVAL;
 369                                 else if (copy_to_user(user_arg + offsetof(
 370                                         struct hidraw_report_descriptor,
 371                                         value[0]),
 372                                         dev->hid->rdesc,
 373                                         min(dev->hid->rsize, len)))
 374                                         ret = -EFAULT;
 375                                 break;
 376                         }
 377                 case HIDIOCGRAWINFO:
 378                         {
 379                                 struct hidraw_devinfo dinfo;
 380
 381                                 dinfo.bustype = dev->hid->bus;
 382                                 dinfo.vendor = dev->hid->vendor;
 383                                 dinfo.product = dev->hid->product;
 384                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 385                                         ret = -EFAULT;
 386                                 break;
 387                         }
 388                 default:
 389                         {
 390                                 struct hid_device *hid = dev->hid;
 391                                 if (_IOC_TYPE(cmd) != 'H') {
 392                                         ret = -EINVAL;
 393                                         break;
 394                                 }
 395
 396                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
 397                                         int len = _IOC_SIZE(cmd);
 398                                         ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
 399                                         break;
 400                                 }
 401                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
 402                                         int len = _IOC_SIZE(cmd);
 403                                         ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
 404                                         break;
 405                                 }
 406
 407                                 /* Begin Read-only ioctls. */
 408                                 if (_IOC_DIR(cmd) != _IOC_READ) {
 409                                         ret = -EINVAL;
 410                                         break;
 411                                 }
 412
 413                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 414                                         int len = strlen(hid->name) + 1;
 415                                         if (len > _IOC_SIZE(cmd))
 416                                                 len = _IOC_SIZE(cmd);
 417                                         ret = copy_to_user(user_arg, hid->name, len) ?
 418                                                 -EFAULT : len;
 419                                         break;
 420                                 }
 421
 422                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 423                                         int len = strlen(hid->phys) + 1;
 424                                         if (len > _IOC_SIZE(cmd))
 425                                                 len = _IOC_SIZE(cmd);
 426                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 427                                                 -EFAULT : len;
 428                                         break;
 429                                 }
 430                         }
 431
 432                 ret = -ENOTTY;
 433         }
 434 out:
 435         mutex_unlock(&minors_lock);
 436         return ret;
 437 }
 438
 439 static const struct file_operations hidraw_ops = {
 440         .owner =        THIS_MODULE,
 441         .read =         hidraw_read,
 442         .write =        hidraw_write,
 443         .poll =         hidraw_poll,
 444         .open =         hidraw_open,
 445         .release =      hidraw_release,
 446         .unlocked_ioctl = hidraw_ioctl,
 447         .fasync =       hidraw_fasync,
 448 #ifdef CONFIG_COMPAT
 449         .compat_ioctl   = hidraw_ioctl,
 450 #endif
 451         .llseek =       noop_llseek,
 452 };
 453
 454 int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 455 {
 456         struct hidraw *dev = hid->hidraw;
 457         struct hidraw_list *list;
 458         int ret = 0;
 459
 460         list_for_each_entry(list, &dev->list, node) {
 461                 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 462
 463                 if (new_head == list->tail)
 464                         continue;
 465
 466                 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
 467                         ret = -ENOMEM;
 468                         break;
 469                 }
 470                 list->buffer[list->head].len = len;
 471                 list->head = new_head;
 472                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 473         }
 474
 475         wake_up_interruptible(&dev->wait);
 476         return ret;
 477 }
 478 EXPORT_SYMBOL_GPL(hidraw_report_event);
 479
 480 int hidraw_connect(struct hid_device *hid)
 481 {
 482         int minor, result;
 483         struct hidraw *dev;
 484
 485         /* we accept any HID device, no matter the applications */
 486
 487         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 488         if (!dev)
 489                 return -ENOMEM;
 490
 491         result = -EINVAL;
 492
 493         mutex_lock(&minors_lock);
 494
 495         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 496                 if (hidraw_table[minor])
 497                         continue;
 498                 hidraw_table[minor] = dev;
 499                 result = 0;
 500                 break;
 501         }
 502
 503         if (result) {
 504                 mutex_unlock(&minors_lock);
 505                 kfree(dev);
 506                 goto out;
 507         }
 508
 509         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 510                                  NULL, "%s%d", "hidraw", minor);
 511
 512         if (IS_ERR(dev->dev)) {
 513                 hidraw_table[minor] = NULL;
 514                 mutex_unlock(&minors_lock);
 515                 result = PTR_ERR(dev->dev);
 516                 kfree(dev);
 517                 goto out;
 518         }
 519
 520         mutex_unlock(&minors_lock);
 521         init_waitqueue_head(&dev->wait);
 522         INIT_LIST_HEAD(&dev->list);
 523
 524         dev->hid = hid;
 525         dev->minor = minor;
 526
 527         dev->exist = 1;
 528         hid->hidraw = dev;
 529
 530 out:
 531         return result;
 532
 533 }
 534 EXPORT_SYMBOL_GPL(hidraw_connect);
 535
 536 void hidraw_disconnect(struct hid_device *hid)
 537 {
 538         struct hidraw *hidraw = hid->hidraw;
 539
 540         mutex_lock(&minors_lock);
 541
 542         drop_ref(hidraw, 1);
 543
 544         mutex_unlock(&minors_lock);
 545 }
 546 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 547
 548 int __init hidraw_init(void)
 549 {
 550         int result;
 551         dev_t dev_id;
 552
 553         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 554                         HIDRAW_MAX_DEVICES, "hidraw");
 555
 556         hidraw_major = MAJOR(dev_id);
 557
 558         if (result < 0) {
 559                 pr_warn("can't get major number\n");
 560                 goto out;
 561         }
 562
 563         hidraw_class = class_create(THIS_MODULE, "hidraw");
 564         if (IS_ERR(hidraw_class)) {
 565                 result = PTR_ERR(hidraw_class);
 566                 goto error_cdev;
 567         }
 568
 569         cdev_init(&hidraw_cdev, &hidraw_ops);
 570         result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 571         if (result < 0)
 572                 goto error_class;
 573
 574         printk(KERN_INFO "hidraw: raw HID events driver (C) Jiri Kosina\n");
 575 out:
 576         return result;
 577
 578 error_class:
 579         class_destroy(hidraw_class);
 580 error_cdev:
 581         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 582         goto out;
 583 }
 584
 585 void hidraw_exit(void)
 586 {
 587         dev_t dev_id = MKDEV(hidraw_major, 0);
 588
 589         cdev_del(&hidraw_cdev);
 590         class_destroy(hidraw_class);
 591         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 592
 593 }