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 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 106 {
 107         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 108         struct hid_device *dev;
 109         __u8 *buf;
 110         int ret = 0;
 111
 112         mutex_lock(&minors_lock);
 113
 114         if (!hidraw_table[minor]) {
 115                 ret = -ENODEV;
 116                 goto out;
 117         }
 118
 119         dev = hidraw_table[minor]->hid;
 120
 121         if (!dev->hid_output_raw_report) {
 122                 ret = -ENODEV;
 123                 goto out;
 124         }
 125
 126         if (count > HID_MAX_BUFFER_SIZE) {
 127                 hid_warn(dev, "pid %d passed too large report\n",
 128                          task_pid_nr(current));
 129                 ret = -EINVAL;
 130                 goto out;
 131         }
 132
 133         if (count < 2) {
 134                 hid_warn(dev, "pid %d passed too short report\n",
 135                          task_pid_nr(current));
 136                 ret = -EINVAL;
 137                 goto out;
 138         }
 139
 140         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 141         if (!buf) {
 142                 ret = -ENOMEM;
 143                 goto out;
 144         }
 145
 146         if (copy_from_user(buf, buffer, count)) {
 147                 ret = -EFAULT;
 148                 goto out_free;
 149         }
 150
 151         ret = dev->hid_output_raw_report(dev, buf, count, HID_OUTPUT_REPORT);
 152 out_free:
 153         kfree(buf);
 154 out:
 155         mutex_unlock(&minors_lock);
 156         return ret;
 157 }
 158
 159 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 160 {
 161         struct hidraw_list *list = file->private_data;
 162
 163         poll_wait(file, &list->hidraw->wait, wait);
 164         if (list->head != list->tail)
 165                 return POLLIN | POLLRDNORM;
 166         if (!list->hidraw->exist)
 167                 return POLLERR | POLLHUP;
 168         return 0;
 169 }
 170
 171 static int hidraw_open(struct inode *inode, struct file *file)
 172 {
 173         unsigned int minor = iminor(inode);
 174         struct hidraw *dev;
 175         struct hidraw_list *list;
 176         int err = 0;
 177
 178         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 179                 err = -ENOMEM;
 180                 goto out;
 181         }
 182
 183         mutex_lock(&minors_lock);
 184         if (!hidraw_table[minor]) {
 185                 kfree(list);
 186                 err = -ENODEV;
 187                 goto out_unlock;
 188         }
 189
 190         list->hidraw = hidraw_table[minor];
 191         mutex_init(&list->read_mutex);
 192         list_add_tail(&list->node, &hidraw_table[minor]->list);
 193         file->private_data = list;
 194
 195         dev = hidraw_table[minor];
 196         if (!dev->open++) {
 197                 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
 198                 if (err < 0)
 199                         goto out_unlock;
 200
 201                 err = hid_hw_open(dev->hid);
 202                 if (err < 0) {
 203                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 204                         dev->open--;
 205                 }
 206         }
 207
 208 out_unlock:
 209         mutex_unlock(&minors_lock);
 210 out:
 211         return err;
 212
 213 }
 214
 215 static int hidraw_release(struct inode * inode, struct file * file)
 216 {
 217         unsigned int minor = iminor(inode);
 218         struct hidraw *dev;
 219         struct hidraw_list *list = file->private_data;
 220         int ret;
 221
 222         mutex_lock(&minors_lock);
 223         if (!hidraw_table[minor]) {
 224                 ret = -ENODEV;
 225                 goto unlock;
 226         }
 227
 228         list_del(&list->node);
 229         dev = hidraw_table[minor];
 230         if (!--dev->open) {
 231                 if (list->hidraw->exist) {
 232                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 233                         hid_hw_close(dev->hid);
 234                 } else {
 235                         kfree(list->hidraw);
 236                 }
 237         }
 238         kfree(list);
 239         ret = 0;
 240 unlock:
 241         mutex_unlock(&minors_lock);
 242
 243         return ret;
 244 }
 245
 246 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 247                                                         unsigned long arg)
 248 {
 249         struct inode *inode = file->f_path.dentry->d_inode;
 250         unsigned int minor = iminor(inode);
 251         long ret = 0;
 252         struct hidraw *dev;
 253         void __user *user_arg = (void __user*) arg;
 254
 255         mutex_lock(&minors_lock);
 256         dev = hidraw_table[minor];
 257         if (!dev) {
 258                 ret = -ENODEV;
 259                 goto out;
 260         }
 261
 262         switch (cmd) {
 263                 case HIDIOCGRDESCSIZE:
 264                         if (put_user(dev->hid->rsize, (int __user *)arg))
 265                                 ret = -EFAULT;
 266                         break;
 267
 268                 case HIDIOCGRDESC:
 269                         {
 270                                 __u32 len;
 271
 272                                 if (get_user(len, (int __user *)arg))
 273                                         ret = -EFAULT;
 274                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 275                                         ret = -EINVAL;
 276                                 else if (copy_to_user(user_arg + offsetof(
 277                                         struct hidraw_report_descriptor,
 278                                         value[0]),
 279                                         dev->hid->rdesc,
 280                                         min(dev->hid->rsize, len)))
 281                                         ret = -EFAULT;
 282                                 break;
 283                         }
 284                 case HIDIOCGRAWINFO:
 285                         {
 286                                 struct hidraw_devinfo dinfo;
 287
 288                                 dinfo.bustype = dev->hid->bus;
 289                                 dinfo.vendor = dev->hid->vendor;
 290                                 dinfo.product = dev->hid->product;
 291                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 292                                         ret = -EFAULT;
 293                                 break;
 294                         }
 295                 default:
 296                         {
 297                                 struct hid_device *hid = dev->hid;
 298                                 if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ) {
 299                                         ret = -EINVAL;
 300                                         break;
 301                                 }
 302
 303                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 304                                         int len;
 305                                         if (!hid->name) {
 306                                                 ret = 0;
 307                                                 break;
 308                                         }
 309                                         len = strlen(hid->name) + 1;
 310                                         if (len > _IOC_SIZE(cmd))
 311                                                 len = _IOC_SIZE(cmd);
 312                                         ret = copy_to_user(user_arg, hid->name, len) ?
 313                                                 -EFAULT : len;
 314                                         break;
 315                                 }
 316
 317                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 318                                         int len;
 319                                         if (!hid->phys) {
 320                                                 ret = 0;
 321                                                 break;
 322                                         }
 323                                         len = strlen(hid->phys) + 1;
 324                                         if (len > _IOC_SIZE(cmd))
 325                                                 len = _IOC_SIZE(cmd);
 326                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 327                                                 -EFAULT : len;
 328                                         break;
 329                                 }
 330                 }
 331
 332                 ret = -ENOTTY;
 333         }
 334 out:
 335         mutex_unlock(&minors_lock);
 336         return ret;
 337 }
 338
 339 static const struct file_operations hidraw_ops = {
 340         .owner =        THIS_MODULE,
 341         .read =         hidraw_read,
 342         .write =        hidraw_write,
 343         .poll =         hidraw_poll,
 344         .open =         hidraw_open,
 345         .release =      hidraw_release,
 346         .unlocked_ioctl = hidraw_ioctl,
 347         .llseek =       noop_llseek,
 348 };
 349
 350 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 351 {
 352         struct hidraw *dev = hid->hidraw;
 353         struct hidraw_list *list;
 354
 355         list_for_each_entry(list, &dev->list, node) {
 356                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 357                 list->buffer[list->head].len = len;
 358                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 359                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 360         }
 361
 362         wake_up_interruptible(&dev->wait);
 363 }
 364 EXPORT_SYMBOL_GPL(hidraw_report_event);
 365
 366 int hidraw_connect(struct hid_device *hid)
 367 {
 368         int minor, result;
 369         struct hidraw *dev;
 370
 371         /* we accept any HID device, no matter the applications */
 372
 373         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 374         if (!dev)
 375                 return -ENOMEM;
 376
 377         result = -EINVAL;
 378
 379         mutex_lock(&minors_lock);
 380
 381         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 382                 if (hidraw_table[minor])
 383                         continue;
 384                 hidraw_table[minor] = dev;
 385                 result = 0;
 386                 break;
 387         }
 388
 389         if (result) {
 390                 mutex_unlock(&minors_lock);
 391                 kfree(dev);
 392                 goto out;
 393         }
 394
 395         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 396                                  NULL, "%s%d", "hidraw", minor);
 397
 398         if (IS_ERR(dev->dev)) {
 399                 hidraw_table[minor] = NULL;
 400                 mutex_unlock(&minors_lock);
 401                 result = PTR_ERR(dev->dev);
 402                 kfree(dev);
 403                 goto out;
 404         }
 405
 406         mutex_unlock(&minors_lock);
 407         init_waitqueue_head(&dev->wait);
 408         INIT_LIST_HEAD(&dev->list);
 409
 410         dev->hid = hid;
 411         dev->minor = minor;
 412
 413         dev->exist = 1;
 414         hid->hidraw = dev;
 415
 416 out:
 417         return result;
 418
 419 }
 420 EXPORT_SYMBOL_GPL(hidraw_connect);
 421
 422 void hidraw_disconnect(struct hid_device *hid)
 423 {
 424         struct hidraw *hidraw = hid->hidraw;
 425
 426         hidraw->exist = 0;
 427
 428         mutex_lock(&minors_lock);
 429         hidraw_table[hidraw->minor] = NULL;
 430         mutex_unlock(&minors_lock);
 431
 432         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 433
 434         if (hidraw->open) {
 435                 hid_hw_close(hid);
 436                 wake_up_interruptible(&hidraw->wait);
 437         } else {
 438                 kfree(hidraw);
 439         }
 440 }
 441 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 442
 443 int __init hidraw_init(void)
 444 {
 445         int result;
 446         dev_t dev_id;
 447
 448         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 449                         HIDRAW_MAX_DEVICES, "hidraw");
 450
 451         hidraw_major = MAJOR(dev_id);
 452
 453         if (result < 0) {
 454                 pr_warn("can't get major number\n");
 455                 result = 0;
 456                 goto out;
 457         }
 458
 459         hidraw_class = class_create(THIS_MODULE, "hidraw");
 460         if (IS_ERR(hidraw_class)) {
 461                 result = PTR_ERR(hidraw_class);
 462                 unregister_chrdev(hidraw_major, "hidraw");
 463                 goto out;
 464         }
 465
 466         cdev_init(&hidraw_cdev, &hidraw_ops);
 467         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 468 out:
 469         return result;
 470 }
 471
 472 void hidraw_exit(void)
 473 {
 474         dev_t dev_id = MKDEV(hidraw_major, 0);
 475
 476         cdev_del(&hidraw_cdev);
 477         class_destroy(hidraw_class);
 478         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 479
 480 }