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 #include <linux/fs.h>
  23 #include <linux/module.h>
  24 #include <linux/errno.h>
  25 #include <linux/kernel.h>
  26 #include <linux/init.h>
  27 #include <linux/cdev.h>
  28 #include <linux/poll.h>
  29 #include <linux/device.h>
  30 #include <linux/major.h>
  31 #include <linux/slab.h>
  32 #include <linux/hid.h>
  33 #include <linux/mutex.h>
  34 #include <linux/sched.h>
  35 #include <linux/smp_lock.h>
  36
  37 #include <linux/hidraw.h>
  38
  39 static int hidraw_major;
  40 static struct cdev hidraw_cdev;
  41 static struct class *hidraw_class;
  42 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
  43 static DEFINE_MUTEX(minors_lock);
  44
  45 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
  46 {
  47         struct hidraw_list *list = file->private_data;
  48         int ret = 0, len;
  49         char *report;
  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                 report = list->buffer[list->tail].value;
  88                 len = list->buffer[list->tail].len > count ?
  89                         count : list->buffer[list->tail].len;
  90
  91                 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
  92                         ret = -EFAULT;
  93                         goto out;
  94                 }
  95                 ret += len;
  96
  97                 kfree(list->buffer[list->tail].value);
  98                 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
  99         }
 100 out:
 101         mutex_unlock(&list->read_mutex);
 102         return ret;
 103 }
 104
 105 /* the first byte is expected to be a report number */
 106 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 107 {
 108         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 109         /* FIXME: What stops hidraw_table going NULL */
 110         struct hid_device *dev = hidraw_table[minor]->hid;
 111         __u8 *buf;
 112         int ret = 0;
 113
 114         if (!dev->hid_output_raw_report)
 115                 return -ENODEV;
 116
 117         if (count > HID_MAX_BUFFER_SIZE) {
 118                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 119                                 task_pid_nr(current));
 120                 return -EINVAL;
 121         }
 122
 123         if (count < 2) {
 124                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 125                                 task_pid_nr(current));
 126                 return -EINVAL;
 127         }
 128
 129         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 130         if (!buf)
 131                 return -ENOMEM;
 132
 133         if (copy_from_user(buf, buffer, count)) {
 134                 ret = -EFAULT;
 135                 goto out;
 136         }
 137
 138         ret = dev->hid_output_raw_report(dev, buf, count, HID_OUTPUT_REPORT);
 139 out:
 140         kfree(buf);
 141         return ret;
 142 }
 143
 144 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 145 {
 146         struct hidraw_list *list = file->private_data;
 147
 148         poll_wait(file, &list->hidraw->wait, wait);
 149         if (list->head != list->tail)
 150                 return POLLIN | POLLRDNORM;
 151         if (!list->hidraw->exist)
 152                 return POLLERR | POLLHUP;
 153         return 0;
 154 }
 155
 156 static int hidraw_open(struct inode *inode, struct file *file)
 157 {
 158         unsigned int minor = iminor(inode);
 159         struct hidraw *dev;
 160         struct hidraw_list *list;
 161         int err = 0;
 162
 163         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 164                 err = -ENOMEM;
 165                 goto out;
 166         }
 167
 168         lock_kernel();
 169         mutex_lock(&minors_lock);
 170         if (!hidraw_table[minor]) {
 171                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
 172                                 minor);
 173                 kfree(list);
 174                 err = -ENODEV;
 175                 goto out_unlock;
 176         }
 177
 178         list->hidraw = hidraw_table[minor];
 179         mutex_init(&list->read_mutex);
 180         list_add_tail(&list->node, &hidraw_table[minor]->list);
 181         file->private_data = list;
 182
 183         dev = hidraw_table[minor];
 184         if (!dev->open++) {
 185                 if (dev->hid->ll_driver->power) {
 186                         err = dev->hid->ll_driver->power(dev->hid, PM_HINT_FULLON);
 187                         if (err < 0)
 188                                 goto out_unlock;
 189                 }
 190                 err = dev->hid->ll_driver->open(dev->hid);
 191                 if (err < 0) {
 192                         if (dev->hid->ll_driver->power)
 193                                 dev->hid->ll_driver->power(dev->hid, PM_HINT_NORMAL);
 194                         dev->open--;
 195                 }
 196         }
 197
 198 out_unlock:
 199         mutex_unlock(&minors_lock);
 200         unlock_kernel();
 201 out:
 202         return err;
 203
 204 }
 205
 206 static int hidraw_release(struct inode * inode, struct file * file)
 207 {
 208         unsigned int minor = iminor(inode);
 209         struct hidraw *dev;
 210         struct hidraw_list *list = file->private_data;
 211
 212         if (!hidraw_table[minor]) {
 213                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
 214                                 minor);
 215                 return -ENODEV;
 216         }
 217
 218         list_del(&list->node);
 219         dev = hidraw_table[minor];
 220         if (!--dev->open) {
 221                 if (list->hidraw->exist) {
 222                         if (dev->hid->ll_driver->power)
 223                                 dev->hid->ll_driver->power(dev->hid, PM_HINT_NORMAL);
 224                         dev->hid->ll_driver->close(dev->hid);
 225                 } else {
 226                         kfree(list->hidraw);
 227                 }
 228         }
 229
 230         kfree(list);
 231
 232         return 0;
 233 }
 234
 235 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 236                                                         unsigned long arg)
 237 {
 238         struct inode *inode = file->f_path.dentry->d_inode;
 239         unsigned int minor = iminor(inode);
 240         long ret = 0;
 241         /* FIXME: What stops hidraw_table going NULL */
 242         struct hidraw *dev = hidraw_table[minor];
 243         void __user *user_arg = (void __user*) arg;
 244
 245         lock_kernel();
 246         switch (cmd) {
 247                 case HIDIOCGRDESCSIZE:
 248                         if (put_user(dev->hid->rsize, (int __user *)arg))
 249                                 ret = -EFAULT;
 250                         break;
 251
 252                 case HIDIOCGRDESC:
 253                         {
 254                                 __u32 len;
 255
 256                                 if (get_user(len, (int __user *)arg))
 257                                         ret = -EFAULT;
 258                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 259                                         ret = -EINVAL;
 260                                 else if (copy_to_user(user_arg + offsetof(
 261                                         struct hidraw_report_descriptor,
 262                                         value[0]),
 263                                         dev->hid->rdesc,
 264                                         min(dev->hid->rsize, len)))
 265                                         ret = -EFAULT;
 266                                 break;
 267                         }
 268                 case HIDIOCGRAWINFO:
 269                         {
 270                                 struct hidraw_devinfo dinfo;
 271
 272                                 dinfo.bustype = dev->hid->bus;
 273                                 dinfo.vendor = dev->hid->vendor;
 274                                 dinfo.product = dev->hid->product;
 275                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 276                                         ret = -EFAULT;
 277                                 break;
 278                         }
 279                 default:
 280                         {
 281                                 struct hid_device *hid = dev->hid;
 282                                 if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ) {
 283                                         ret = -EINVAL;
 284                                         break;
 285                                 }
 286
 287                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 288                                         int len;
 289                                         if (!hid->name) {
 290                                                 ret = 0;
 291                                                 break;
 292                                         }
 293                                         len = strlen(hid->name) + 1;
 294                                         if (len > _IOC_SIZE(cmd))
 295                                                 len = _IOC_SIZE(cmd);
 296                                         ret = copy_to_user(user_arg, hid->name, len) ?
 297                                                 -EFAULT : len;
 298                                         break;
 299                                 }
 300
 301                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 302                                         int len;
 303                                         if (!hid->phys) {
 304                                                 ret = 0;
 305                                                 break;
 306                                         }
 307                                         len = strlen(hid->phys) + 1;
 308                                         if (len > _IOC_SIZE(cmd))
 309                                                 len = _IOC_SIZE(cmd);
 310                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 311                                                 -EFAULT : len;
 312                                         break;
 313                                 }
 314                 }
 315
 316                 ret = -ENOTTY;
 317         }
 318         unlock_kernel();
 319         return ret;
 320 }
 321
 322 static const struct file_operations hidraw_ops = {
 323         .owner =        THIS_MODULE,
 324         .read =         hidraw_read,
 325         .write =        hidraw_write,
 326         .poll =         hidraw_poll,
 327         .open =         hidraw_open,
 328         .release =      hidraw_release,
 329         .unlocked_ioctl = hidraw_ioctl,
 330 };
 331
 332 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 333 {
 334         struct hidraw *dev = hid->hidraw;
 335         struct hidraw_list *list;
 336
 337         list_for_each_entry(list, &dev->list, node) {
 338                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 339                 list->buffer[list->head].len = len;
 340                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 341                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 342         }
 343
 344         wake_up_interruptible(&dev->wait);
 345 }
 346 EXPORT_SYMBOL_GPL(hidraw_report_event);
 347
 348 int hidraw_connect(struct hid_device *hid)
 349 {
 350         int minor, result;
 351         struct hidraw *dev;
 352
 353         /* we accept any HID device, no matter the applications */
 354
 355         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 356         if (!dev)
 357                 return -ENOMEM;
 358
 359         result = -EINVAL;
 360
 361         mutex_lock(&minors_lock);
 362
 363         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 364                 if (hidraw_table[minor])
 365                         continue;
 366                 hidraw_table[minor] = dev;
 367                 result = 0;
 368                 break;
 369         }
 370
 371         if (result) {
 372                 mutex_unlock(&minors_lock);
 373                 kfree(dev);
 374                 goto out;
 375         }
 376
 377         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 378                                  NULL, "%s%d", "hidraw", minor);
 379
 380         if (IS_ERR(dev->dev)) {
 381                 hidraw_table[minor] = NULL;
 382                 mutex_unlock(&minors_lock);
 383                 result = PTR_ERR(dev->dev);
 384                 kfree(dev);
 385                 goto out;
 386         }
 387
 388         mutex_unlock(&minors_lock);
 389         init_waitqueue_head(&dev->wait);
 390         INIT_LIST_HEAD(&dev->list);
 391
 392         dev->hid = hid;
 393         dev->minor = minor;
 394
 395         dev->exist = 1;
 396         hid->hidraw = dev;
 397
 398 out:
 399         return result;
 400
 401 }
 402 EXPORT_SYMBOL_GPL(hidraw_connect);
 403
 404 void hidraw_disconnect(struct hid_device *hid)
 405 {
 406         struct hidraw *hidraw = hid->hidraw;
 407
 408         hidraw->exist = 0;
 409
 410         mutex_lock(&minors_lock);
 411         hidraw_table[hidraw->minor] = NULL;
 412         mutex_unlock(&minors_lock);
 413
 414         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 415
 416         if (hidraw->open) {
 417                 hid->ll_driver->close(hid);
 418                 wake_up_interruptible(&hidraw->wait);
 419         } else {
 420                 kfree(hidraw);
 421         }
 422 }
 423 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 424
 425 int __init hidraw_init(void)
 426 {
 427         int result;
 428         dev_t dev_id;
 429
 430         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 431                         HIDRAW_MAX_DEVICES, "hidraw");
 432
 433         hidraw_major = MAJOR(dev_id);
 434
 435         if (result < 0) {
 436                 printk(KERN_WARNING "hidraw: can't get major number\n");
 437                 result = 0;
 438                 goto out;
 439         }
 440
 441         hidraw_class = class_create(THIS_MODULE, "hidraw");
 442         if (IS_ERR(hidraw_class)) {
 443                 result = PTR_ERR(hidraw_class);
 444                 unregister_chrdev(hidraw_major, "hidraw");
 445                 goto out;
 446         }
 447
 448         cdev_init(&hidraw_cdev, &hidraw_ops);
 449         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 450 out:
 451         return result;
 452 }
 453
 454 void hidraw_exit(void)
 455 {
 456         dev_t dev_id = MKDEV(hidraw_major, 0);
 457
 458         cdev_del(&hidraw_cdev);
 459         class_destroy(hidraw_class);
 460         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 461
 462 }