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         DECLARE_WAITQUEUE(wait, current);
  50
  51         mutex_lock(&list->read_mutex);
  52
  53         while (ret == 0) {
  54                 if (list->head == list->tail) {
  55                         add_wait_queue(&list->hidraw->wait, &wait);
  56                         set_current_state(TASK_INTERRUPTIBLE);
  57
  58                         while (list->head == list->tail) {
  59                                 if (file->f_flags & O_NONBLOCK) {
  60                                         ret = -EAGAIN;
  61                                         break;
  62                                 }
  63                                 if (signal_pending(current)) {
  64                                         ret = -ERESTARTSYS;
  65                                         break;
  66                                 }
  67                                 if (!list->hidraw->exist) {
  68                                         ret = -EIO;
  69                                         break;
  70                                 }
  71
  72                                 /* allow O_NONBLOCK to work well from other threads */
  73                                 mutex_unlock(&list->read_mutex);
  74                                 schedule();
  75                                 mutex_lock(&list->read_mutex);
  76                                 set_current_state(TASK_INTERRUPTIBLE);
  77                         }
  78
  79                         set_current_state(TASK_RUNNING);
  80                         remove_wait_queue(&list->hidraw->wait, &wait);
  81                 }
  82
  83                 if (ret)
  84                         goto out;
  85
  86                 len = list->buffer[list->tail].len > count ?
  87                         count : list->buffer[list->tail].len;
  88
  89                 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
  90                         ret = -EFAULT;
  91                         goto out;
  92                 }
  93                 ret += len;
  94
  95                 kfree(list->buffer[list->tail].value);
  96                 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
  97         }
  98 out:
  99         mutex_unlock(&list->read_mutex);
 100         return ret;
 101 }
 102
 103 /* the first byte is expected to be a report number */
 104 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 105 {
 106         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 107         struct hid_device *dev;
 108         __u8 *buf;
 109         int ret = 0;
 110
 111         mutex_lock(&minors_lock);
 112         dev = hidraw_table[minor]->hid;
 113
 114         if (!dev->hid_output_raw_report) {
 115                 ret = -ENODEV;
 116                 goto out;
 117         }
 118
 119         if (count > HID_MAX_BUFFER_SIZE) {
 120                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 121                                 task_pid_nr(current));
 122                 ret = -EINVAL;
 123                 goto out;
 124         }
 125
 126         if (count < 2) {
 127                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 128                                 task_pid_nr(current));
 129                 ret = -EINVAL;
 130                 goto out;
 131         }
 132
 133         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 134         if (!buf) {
 135                 ret = -ENOMEM;
 136                 goto out;
 137         }
 138
 139         if (copy_from_user(buf, buffer, count)) {
 140                 ret = -EFAULT;
 141                 goto out_free;
 142         }
 143
 144         ret = dev->hid_output_raw_report(dev, buf, count, HID_OUTPUT_REPORT);
 145 out_free:
 146         kfree(buf);
 147 out:
 148         mutex_unlock(&minors_lock);
 149         return ret;
 150 }
 151
 152 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 153 {
 154         struct hidraw_list *list = file->private_data;
 155
 156         poll_wait(file, &list->hidraw->wait, wait);
 157         if (list->head != list->tail)
 158                 return POLLIN | POLLRDNORM;
 159         if (!list->hidraw->exist)
 160                 return POLLERR | POLLHUP;
 161         return 0;
 162 }
 163
 164 static int hidraw_open(struct inode *inode, struct file *file)
 165 {
 166         unsigned int minor = iminor(inode);
 167         struct hidraw *dev;
 168         struct hidraw_list *list;
 169         int err = 0;
 170
 171         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 172                 err = -ENOMEM;
 173                 goto out;
 174         }
 175
 176         mutex_lock(&minors_lock);
 177         if (!hidraw_table[minor]) {
 178                 kfree(list);
 179                 err = -ENODEV;
 180                 goto out_unlock;
 181         }
 182
 183         list->hidraw = hidraw_table[minor];
 184         mutex_init(&list->read_mutex);
 185         list_add_tail(&list->node, &hidraw_table[minor]->list);
 186         file->private_data = list;
 187
 188         dev = hidraw_table[minor];
 189         if (!dev->open++) {
 190                 if (dev->hid->ll_driver->power) {
 191                         err = dev->hid->ll_driver->power(dev->hid, PM_HINT_FULLON);
 192                         if (err < 0)
 193                                 goto out_unlock;
 194                 }
 195                 err = dev->hid->ll_driver->open(dev->hid);
 196                 if (err < 0) {
 197                         if (dev->hid->ll_driver->power)
 198                                 dev->hid->ll_driver->power(dev->hid, PM_HINT_NORMAL);
 199                         dev->open--;
 200                 }
 201         }
 202
 203 out_unlock:
 204         mutex_unlock(&minors_lock);
 205 out:
 206         return err;
 207
 208 }
 209
 210 static int hidraw_release(struct inode * inode, struct file * file)
 211 {
 212         unsigned int minor = iminor(inode);
 213         struct hidraw *dev;
 214         struct hidraw_list *list = file->private_data;
 215
 216         if (!hidraw_table[minor])
 217                 return -ENODEV;
 218
 219         list_del(&list->node);
 220         dev = hidraw_table[minor];
 221         if (!--dev->open) {
 222                 if (list->hidraw->exist) {
 223                         if (dev->hid->ll_driver->power)
 224                                 dev->hid->ll_driver->power(dev->hid, PM_HINT_NORMAL);
 225                         dev->hid->ll_driver->close(dev->hid);
 226                 } else {
 227                         kfree(list->hidraw);
 228                 }
 229         }
 230
 231         kfree(list);
 232
 233         return 0;
 234 }
 235
 236 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 237                                                         unsigned long arg)
 238 {
 239         struct inode *inode = file->f_path.dentry->d_inode;
 240         unsigned int minor = iminor(inode);
 241         long ret = 0;
 242         struct hidraw *dev;
 243         void __user *user_arg = (void __user*) arg;
 244
 245         mutex_lock(&minors_lock);
 246         dev = hidraw_table[minor];
 247
 248         switch (cmd) {
 249                 case HIDIOCGRDESCSIZE:
 250                         if (put_user(dev->hid->rsize, (int __user *)arg))
 251                                 ret = -EFAULT;
 252                         break;
 253
 254                 case HIDIOCGRDESC:
 255                         {
 256                                 __u32 len;
 257
 258                                 if (get_user(len, (int __user *)arg))
 259                                         ret = -EFAULT;
 260                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 261                                         ret = -EINVAL;
 262                                 else if (copy_to_user(user_arg + offsetof(
 263                                         struct hidraw_report_descriptor,
 264                                         value[0]),
 265                                         dev->hid->rdesc,
 266                                         min(dev->hid->rsize, len)))
 267                                         ret = -EFAULT;
 268                                 break;
 269                         }
 270                 case HIDIOCGRAWINFO:
 271                         {
 272                                 struct hidraw_devinfo dinfo;
 273
 274                                 dinfo.bustype = dev->hid->bus;
 275                                 dinfo.vendor = dev->hid->vendor;
 276                                 dinfo.product = dev->hid->product;
 277                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 278                                         ret = -EFAULT;
 279                                 break;
 280                         }
 281                 default:
 282                         {
 283                                 struct hid_device *hid = dev->hid;
 284                                 if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ) {
 285                                         ret = -EINVAL;
 286                                         break;
 287                                 }
 288
 289                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 290                                         int len;
 291                                         if (!hid->name) {
 292                                                 ret = 0;
 293                                                 break;
 294                                         }
 295                                         len = strlen(hid->name) + 1;
 296                                         if (len > _IOC_SIZE(cmd))
 297                                                 len = _IOC_SIZE(cmd);
 298                                         ret = copy_to_user(user_arg, hid->name, len) ?
 299                                                 -EFAULT : len;
 300                                         break;
 301                                 }
 302
 303                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 304                                         int len;
 305                                         if (!hid->phys) {
 306                                                 ret = 0;
 307                                                 break;
 308                                         }
 309                                         len = strlen(hid->phys) + 1;
 310                                         if (len > _IOC_SIZE(cmd))
 311                                                 len = _IOC_SIZE(cmd);
 312                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 313                                                 -EFAULT : len;
 314                                         break;
 315                                 }
 316                 }
 317
 318                 ret = -ENOTTY;
 319         }
 320         mutex_unlock(&minors_lock);
 321         return ret;
 322 }
 323
 324 static const struct file_operations hidraw_ops = {
 325         .owner =        THIS_MODULE,
 326         .read =         hidraw_read,
 327         .write =        hidraw_write,
 328         .poll =         hidraw_poll,
 329         .open =         hidraw_open,
 330         .release =      hidraw_release,
 331         .unlocked_ioctl = hidraw_ioctl,
 332         .llseek =       noop_llseek,
 333 };
 334
 335 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 336 {
 337         struct hidraw *dev = hid->hidraw;
 338         struct hidraw_list *list;
 339
 340         list_for_each_entry(list, &dev->list, node) {
 341                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 342                 list->buffer[list->head].len = len;
 343                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 344                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 345         }
 346
 347         wake_up_interruptible(&dev->wait);
 348 }
 349 EXPORT_SYMBOL_GPL(hidraw_report_event);
 350
 351 int hidraw_connect(struct hid_device *hid)
 352 {
 353         int minor, result;
 354         struct hidraw *dev;
 355
 356         /* we accept any HID device, no matter the applications */
 357
 358         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 359         if (!dev)
 360                 return -ENOMEM;
 361
 362         result = -EINVAL;
 363
 364         mutex_lock(&minors_lock);
 365
 366         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 367                 if (hidraw_table[minor])
 368                         continue;
 369                 hidraw_table[minor] = dev;
 370                 result = 0;
 371                 break;
 372         }
 373
 374         if (result) {
 375                 mutex_unlock(&minors_lock);
 376                 kfree(dev);
 377                 goto out;
 378         }
 379
 380         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 381                                  NULL, "%s%d", "hidraw", minor);
 382
 383         if (IS_ERR(dev->dev)) {
 384                 hidraw_table[minor] = NULL;
 385                 mutex_unlock(&minors_lock);
 386                 result = PTR_ERR(dev->dev);
 387                 kfree(dev);
 388                 goto out;
 389         }
 390
 391         mutex_unlock(&minors_lock);
 392         init_waitqueue_head(&dev->wait);
 393         INIT_LIST_HEAD(&dev->list);
 394
 395         dev->hid = hid;
 396         dev->minor = minor;
 397
 398         dev->exist = 1;
 399         hid->hidraw = dev;
 400
 401 out:
 402         return result;
 403
 404 }
 405 EXPORT_SYMBOL_GPL(hidraw_connect);
 406
 407 void hidraw_disconnect(struct hid_device *hid)
 408 {
 409         struct hidraw *hidraw = hid->hidraw;
 410
 411         hidraw->exist = 0;
 412
 413         mutex_lock(&minors_lock);
 414         hidraw_table[hidraw->minor] = NULL;
 415         mutex_unlock(&minors_lock);
 416
 417         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 418
 419         if (hidraw->open) {
 420                 hid->ll_driver->close(hid);
 421                 wake_up_interruptible(&hidraw->wait);
 422         } else {
 423                 kfree(hidraw);
 424         }
 425 }
 426 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 427
 428 int __init hidraw_init(void)
 429 {
 430         int result;
 431         dev_t dev_id;
 432
 433         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 434                         HIDRAW_MAX_DEVICES, "hidraw");
 435
 436         hidraw_major = MAJOR(dev_id);
 437
 438         if (result < 0) {
 439                 printk(KERN_WARNING "hidraw: can't get major number\n");
 440                 result = 0;
 441                 goto out;
 442         }
 443
 444         hidraw_class = class_create(THIS_MODULE, "hidraw");
 445         if (IS_ERR(hidraw_class)) {
 446                 result = PTR_ERR(hidraw_class);
 447                 unregister_chrdev(hidraw_major, "hidraw");
 448                 goto out;
 449         }
 450
 451         cdev_init(&hidraw_cdev, &hidraw_ops);
 452         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 453 out:
 454         return result;
 455 }
 456
 457 void hidraw_exit(void)
 458 {
 459         dev_t dev_id = MKDEV(hidraw_major, 0);
 460
 461         cdev_del(&hidraw_cdev);
 462         class_destroy(hidraw_class);
 463         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 464
 465 }