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 #include <linux/smp_lock.h>
  38
  39 #include <linux/hidraw.h>
  40
  41 static int hidraw_major;
  42 static struct cdev hidraw_cdev;
  43 static struct class *hidraw_class;
  44 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
  45 static DEFINE_MUTEX(minors_lock);
  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 (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         struct hid_device *dev;
 110         __u8 *buf;
 111         int ret = 0;
 112
 113         mutex_lock(&minors_lock);
 114
 115         if (!hidraw_table[minor]) {
 116                 ret = -ENODEV;
 117                 goto out;
 118         }
 119
 120         dev = hidraw_table[minor]->hid;
 121
 122         if (!dev->hid_output_raw_report) {
 123                 ret = -ENODEV;
 124                 goto out;
 125         }
 126
 127         if (count > HID_MAX_BUFFER_SIZE) {
 128                 hid_warn(dev, "pid %d passed too large report\n",
 129                          task_pid_nr(current));
 130                 ret = -EINVAL;
 131                 goto out;
 132         }
 133
 134         if (count < 2) {
 135                 hid_warn(dev, "pid %d passed too short report\n",
 136                          task_pid_nr(current));
 137                 ret = -EINVAL;
 138                 goto out;
 139         }
 140
 141         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 142         if (!buf) {
 143                 ret = -ENOMEM;
 144                 goto out;
 145         }
 146
 147         if (copy_from_user(buf, buffer, count)) {
 148                 ret = -EFAULT;
 149                 goto out_free;
 150         }
 151
 152         ret = dev->hid_output_raw_report(dev, buf, count, HID_OUTPUT_REPORT);
 153 out_free:
 154         kfree(buf);
 155 out:
 156         mutex_unlock(&minors_lock);
 157         return ret;
 158 }
 159
 160 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 161 {
 162         struct hidraw_list *list = file->private_data;
 163
 164         poll_wait(file, &list->hidraw->wait, wait);
 165         if (list->head != list->tail)
 166                 return POLLIN | POLLRDNORM;
 167         if (!list->hidraw->exist)
 168                 return POLLERR | POLLHUP;
 169         return 0;
 170 }
 171
 172 static int hidraw_open(struct inode *inode, struct file *file)
 173 {
 174         unsigned int minor = iminor(inode);
 175         struct hidraw *dev;
 176         struct hidraw_list *list;
 177         int err = 0;
 178
 179         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 180                 err = -ENOMEM;
 181                 goto out;
 182         }
 183
 184         mutex_lock(&minors_lock);
 185         if (!hidraw_table[minor]) {
 186                 kfree(list);
 187                 err = -ENODEV;
 188                 goto out_unlock;
 189         }
 190
 191         list->hidraw = hidraw_table[minor];
 192         mutex_init(&list->read_mutex);
 193         list_add_tail(&list->node, &hidraw_table[minor]->list);
 194         file->private_data = list;
 195
 196         dev = hidraw_table[minor];
 197         if (!dev->open++) {
 198                 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
 199                 if (err < 0)
 200                         goto out_unlock;
 201
 202                 err = hid_hw_open(dev->hid);
 203                 if (err < 0) {
 204                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 205                         dev->open--;
 206                 }
 207         }
 208
 209 out_unlock:
 210         mutex_unlock(&minors_lock);
 211 out:
 212         return err;
 213
 214 }
 215
 216 static int hidraw_release(struct inode * inode, struct file * file)
 217 {
 218         unsigned int minor = iminor(inode);
 219         struct hidraw *dev;
 220         struct hidraw_list *list = file->private_data;
 221         int ret;
 222
 223         mutex_lock(&minors_lock);
 224         if (!hidraw_table[minor]) {
 225                 ret = -ENODEV;
 226                 goto unlock;
 227         }
 228
 229         list_del(&list->node);
 230         dev = hidraw_table[minor];
 231         if (!--dev->open) {
 232                 if (list->hidraw->exist) {
 233                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 234                         hid_hw_close(dev->hid);
 235                 } else {
 236                         kfree(list->hidraw);
 237                 }
 238         }
 239         kfree(list);
 240         ret = 0;
 241 unlock:
 242         mutex_unlock(&minors_lock);
 243
 244         return ret;
 245 }
 246
 247 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 248                                                         unsigned long arg)
 249 {
 250         struct inode *inode = file->f_path.dentry->d_inode;
 251         unsigned int minor = iminor(inode);
 252         long ret = 0;
 253         struct hidraw *dev;
 254         void __user *user_arg = (void __user*) arg;
 255
 256         mutex_lock(&minors_lock);
 257         dev = hidraw_table[minor];
 258         if (!dev) {
 259                 ret = -ENODEV;
 260                 goto out;
 261         }
 262
 263         switch (cmd) {
 264                 case HIDIOCGRDESCSIZE:
 265                         if (put_user(dev->hid->rsize, (int __user *)arg))
 266                                 ret = -EFAULT;
 267                         break;
 268
 269                 case HIDIOCGRDESC:
 270                         {
 271                                 __u32 len;
 272
 273                                 if (get_user(len, (int __user *)arg))
 274                                         ret = -EFAULT;
 275                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 276                                         ret = -EINVAL;
 277                                 else if (copy_to_user(user_arg + offsetof(
 278                                         struct hidraw_report_descriptor,
 279                                         value[0]),
 280                                         dev->hid->rdesc,
 281                                         min(dev->hid->rsize, len)))
 282                                         ret = -EFAULT;
 283                                 break;
 284                         }
 285                 case HIDIOCGRAWINFO:
 286                         {
 287                                 struct hidraw_devinfo dinfo;
 288
 289                                 dinfo.bustype = dev->hid->bus;
 290                                 dinfo.vendor = dev->hid->vendor;
 291                                 dinfo.product = dev->hid->product;
 292                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 293                                         ret = -EFAULT;
 294                                 break;
 295                         }
 296                 default:
 297                         {
 298                                 struct hid_device *hid = dev->hid;
 299                                 if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ) {
 300                                         ret = -EINVAL;
 301                                         break;
 302                                 }
 303
 304                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 305                                         int len;
 306                                         if (!hid->name) {
 307                                                 ret = 0;
 308                                                 break;
 309                                         }
 310                                         len = strlen(hid->name) + 1;
 311                                         if (len > _IOC_SIZE(cmd))
 312                                                 len = _IOC_SIZE(cmd);
 313                                         ret = copy_to_user(user_arg, hid->name, len) ?
 314                                                 -EFAULT : len;
 315                                         break;
 316                                 }
 317
 318                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 319                                         int len;
 320                                         if (!hid->phys) {
 321                                                 ret = 0;
 322                                                 break;
 323                                         }
 324                                         len = strlen(hid->phys) + 1;
 325                                         if (len > _IOC_SIZE(cmd))
 326                                                 len = _IOC_SIZE(cmd);
 327                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 328                                                 -EFAULT : len;
 329                                         break;
 330                                 }
 331                 }
 332
 333                 ret = -ENOTTY;
 334         }
 335 out:
 336         mutex_unlock(&minors_lock);
 337         return ret;
 338 }
 339
 340 static const struct file_operations hidraw_ops = {
 341         .owner =        THIS_MODULE,
 342         .read =         hidraw_read,
 343         .write =        hidraw_write,
 344         .poll =         hidraw_poll,
 345         .open =         hidraw_open,
 346         .release =      hidraw_release,
 347         .unlocked_ioctl = hidraw_ioctl,
 348         .llseek =       noop_llseek,
 349 };
 350
 351 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 352 {
 353         struct hidraw *dev = hid->hidraw;
 354         struct hidraw_list *list;
 355
 356         list_for_each_entry(list, &dev->list, node) {
 357                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 358                 list->buffer[list->head].len = len;
 359                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 360                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 361         }
 362
 363         wake_up_interruptible(&dev->wait);
 364 }
 365 EXPORT_SYMBOL_GPL(hidraw_report_event);
 366
 367 int hidraw_connect(struct hid_device *hid)
 368 {
 369         int minor, result;
 370         struct hidraw *dev;
 371
 372         /* we accept any HID device, no matter the applications */
 373
 374         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 375         if (!dev)
 376                 return -ENOMEM;
 377
 378         result = -EINVAL;
 379
 380         mutex_lock(&minors_lock);
 381
 382         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 383                 if (hidraw_table[minor])
 384                         continue;
 385                 hidraw_table[minor] = dev;
 386                 result = 0;
 387                 break;
 388         }
 389
 390         if (result) {
 391                 mutex_unlock(&minors_lock);
 392                 kfree(dev);
 393                 goto out;
 394         }
 395
 396         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 397                                  NULL, "%s%d", "hidraw", minor);
 398
 399         if (IS_ERR(dev->dev)) {
 400                 hidraw_table[minor] = NULL;
 401                 mutex_unlock(&minors_lock);
 402                 result = PTR_ERR(dev->dev);
 403                 kfree(dev);
 404                 goto out;
 405         }
 406
 407         mutex_unlock(&minors_lock);
 408         init_waitqueue_head(&dev->wait);
 409         INIT_LIST_HEAD(&dev->list);
 410
 411         dev->hid = hid;
 412         dev->minor = minor;
 413
 414         dev->exist = 1;
 415         hid->hidraw = dev;
 416
 417 out:
 418         return result;
 419
 420 }
 421 EXPORT_SYMBOL_GPL(hidraw_connect);
 422
 423 void hidraw_disconnect(struct hid_device *hid)
 424 {
 425         struct hidraw *hidraw = hid->hidraw;
 426
 427         hidraw->exist = 0;
 428
 429         mutex_lock(&minors_lock);
 430         hidraw_table[hidraw->minor] = NULL;
 431         mutex_unlock(&minors_lock);
 432
 433         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 434
 435         if (hidraw->open) {
 436                 hid_hw_close(hid);
 437                 wake_up_interruptible(&hidraw->wait);
 438         } else {
 439                 kfree(hidraw);
 440         }
 441 }
 442 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 443
 444 int __init hidraw_init(void)
 445 {
 446         int result;
 447         dev_t dev_id;
 448
 449         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 450                         HIDRAW_MAX_DEVICES, "hidraw");
 451
 452         hidraw_major = MAJOR(dev_id);
 453
 454         if (result < 0) {
 455                 pr_warn("can't get major number\n");
 456                 result = 0;
 457                 goto out;
 458         }
 459
 460         hidraw_class = class_create(THIS_MODULE, "hidraw");
 461         if (IS_ERR(hidraw_class)) {
 462                 result = PTR_ERR(hidraw_class);
 463                 unregister_chrdev(hidraw_major, "hidraw");
 464                 goto out;
 465         }
 466
 467         cdev_init(&hidraw_cdev, &hidraw_ops);
 468         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 469 out:
 470         return result;
 471 }
 472
 473 void hidraw_exit(void)
 474 {
 475         dev_t dev_id = MKDEV(hidraw_major, 0);
 476
 477         cdev_del(&hidraw_cdev);
 478         class_destroy(hidraw_class);
 479         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 480
 481 }