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/hid.h>
  32 #include <linux/mutex.h>
  33
  34 #include <linux/hidraw.h>
  35
  36 static int hidraw_major;
  37 static struct cdev hidraw_cdev;
  38 static struct class *hidraw_class;
  39 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
  40 static DEFINE_SPINLOCK(minors_lock);
  41
  42 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
  43 {
  44         struct hidraw_list *list = file->private_data;
  45         int ret = 0, len;
  46         char *report;
  47         DECLARE_WAITQUEUE(wait, current);
  48
  49         while (ret == 0) {
  50
  51                 mutex_lock(&list->read_mutex);
  52
  53                 if (list->head == list->tail) {
  54                         add_wait_queue(&list->hidraw->wait, &wait);
  55                         set_current_state(TASK_INTERRUPTIBLE);
  56
  57                         while (list->head == list->tail) {
  58                                 if (file->f_flags & O_NONBLOCK) {
  59                                         ret = -EAGAIN;
  60                                         break;
  61                                 }
  62                                 if (signal_pending(current)) {
  63                                         ret = -ERESTARTSYS;
  64                                         break;
  65                                 }
  66                                 if (!list->hidraw->exist) {
  67                                         ret = -EIO;
  68                                         break;
  69                                 }
  70
  71                                 /* allow O_NONBLOCK to work well from other threads */
  72                                 mutex_unlock(&list->read_mutex);
  73                                 schedule();
  74                                 mutex_lock(&list->read_mutex);
  75                                 set_current_state(TASK_INTERRUPTIBLE);
  76                         }
  77
  78                         set_current_state(TASK_RUNNING);
  79                         remove_wait_queue(&list->hidraw->wait, &wait);
  80                 }
  81
  82                 if (ret)
  83                         goto out;
  84
  85                 report = list->buffer[list->tail].value;
  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 = hidraw_table[minor]->hid;
 108         __u8 *buf;
 109         int ret = 0;
 110
 111         if (!dev->hid_output_raw_report)
 112                 return -ENODEV;
 113
 114         if (count > HID_MIN_BUFFER_SIZE) {
 115                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 116                                 current->pid);
 117                 return -EINVAL;
 118         }
 119
 120         if (count < 2) {
 121                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 122                                 current->pid);
 123                 return -EINVAL;
 124         }
 125
 126         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 127         if (!buf)
 128                 return -ENOMEM;
 129
 130         if (copy_from_user(buf, buffer, count)) {
 131                 ret = -EFAULT;
 132                 goto out;
 133         }
 134
 135         ret = dev->hid_output_raw_report(dev, buf, count);
 136 out:
 137         kfree(buf);
 138         return ret;
 139 }
 140
 141 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 142 {
 143         struct hidraw_list *list = file->private_data;
 144
 145         poll_wait(file, &list->hidraw->wait, wait);
 146         if (list->head != list->tail)
 147                 return POLLIN | POLLRDNORM;
 148         if (!list->hidraw->exist)
 149                 return POLLERR | POLLHUP;
 150         return 0;
 151 }
 152
 153 static int hidraw_open(struct inode *inode, struct file *file)
 154 {
 155         unsigned int minor = iminor(inode);
 156         struct hidraw *dev;
 157         struct hidraw_list *list;
 158         int err = 0;
 159
 160         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 161                 err = -ENOMEM;
 162                 goto out;
 163         }
 164
 165         spin_lock(&minors_lock);
 166         if (!hidraw_table[minor]) {
 167                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
 168                                 minor);
 169                 kfree(list);
 170                 err = -ENODEV;
 171                 goto out_unlock;
 172         }
 173
 174         list->hidraw = hidraw_table[minor];
 175         mutex_init(&list->read_mutex);
 176         list_add_tail(&list->node, &hidraw_table[minor]->list);
 177         file->private_data = list;
 178
 179         dev = hidraw_table[minor];
 180         if (!dev->open++)
 181                 dev->hid->hid_open(dev->hid);
 182
 183 out_unlock:
 184         spin_unlock(&minors_lock);
 185 out:
 186         return err;
 187
 188 }
 189
 190 static int hidraw_release(struct inode * inode, struct file * file)
 191 {
 192         unsigned int minor = iminor(inode);
 193         struct hidraw *dev;
 194         struct hidraw_list *list = file->private_data;
 195
 196         if (!hidraw_table[minor]) {
 197                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
 198                                 minor);
 199                 return -ENODEV;
 200         }
 201
 202         list_del(&list->node);
 203         dev = hidraw_table[minor];
 204         if (!dev->open--) {
 205                 if (list->hidraw->exist)
 206                         dev->hid->hid_close(dev->hid);
 207                 else
 208                         kfree(list->hidraw);
 209         }
 210
 211         return 0;
 212 }
 213
 214 static int hidraw_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 215 {
 216         unsigned int minor = iminor(inode);
 217         struct hidraw *dev = hidraw_table[minor];
 218         void __user *user_arg = (void __user*) arg;
 219
 220         switch (cmd) {
 221                 case HIDIOCGRDESCSIZE:
 222                         if (put_user(dev->hid->rsize, (int __user *)arg))
 223                                 return -EFAULT;
 224                         return 0;
 225
 226                 case HIDIOCGRDESC:
 227                         {
 228                                 __u32 len;
 229
 230                                 if (get_user(len, (int __user *)arg))
 231                                         return -EFAULT;
 232
 233                                 if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 234                                         return -EINVAL;
 235
 236                                 if (copy_to_user(user_arg + offsetof(
 237                                                                 struct hidraw_report_descriptor,
 238                                                                 value[0]),
 239                                                         dev->hid->rdesc,
 240                                                         min(dev->hid->rsize, len)))
 241                                                 return -EFAULT;
 242                                 return 0;
 243                         }
 244                 case HIDIOCGRAWINFO:
 245                         {
 246                                 struct hidraw_devinfo dinfo;
 247
 248                                 dinfo.bustype = dev->hid->bus;
 249                                 dinfo.vendor = dev->hid->vendor;
 250                                 dinfo.product = dev->hid->product;
 251                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 252                                         return -EFAULT;
 253
 254                                 return 0;
 255                         }
 256                 default:
 257                         printk(KERN_EMERG "hidraw: unsupported ioctl() %x\n",
 258                                         cmd);
 259         }
 260         return -EINVAL;
 261 }
 262
 263 static const struct file_operations hidraw_ops = {
 264         .owner =        THIS_MODULE,
 265         .read =         hidraw_read,
 266         .write =        hidraw_write,
 267         .poll =         hidraw_poll,
 268         .open =         hidraw_open,
 269         .release =      hidraw_release,
 270         .ioctl =        hidraw_ioctl,
 271 };
 272
 273 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 274 {
 275         struct hidraw *dev = hid->hidraw;
 276         struct hidraw_list *list;
 277
 278         list_for_each_entry(list, &dev->list, node) {
 279                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 280                 list->buffer[list->head].len = len;
 281                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 282                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 283         }
 284
 285         wake_up_interruptible(&dev->wait);
 286 }
 287 EXPORT_SYMBOL_GPL(hidraw_report_event);
 288
 289 int hidraw_connect(struct hid_device *hid)
 290 {
 291         int minor, result;
 292         struct hidraw *dev;
 293
 294         /* TODO currently we accept any HID device. This should later
 295          * probably be fixed to accept only those devices which provide
 296          * non-input applications
 297          */
 298
 299         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 300         if (!dev)
 301                 return -ENOMEM;
 302
 303         result = -EINVAL;
 304
 305         spin_lock(&minors_lock);
 306
 307         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 308                 if (hidraw_table[minor])
 309                         continue;
 310                 hidraw_table[minor] = dev;
 311                 result = 0;
 312                 break;
 313         }
 314
 315         spin_unlock(&minors_lock);
 316
 317         if (result) {
 318                 kfree(dev);
 319                 goto out;
 320         }
 321
 322         dev->dev = device_create(hidraw_class, NULL, MKDEV(hidraw_major, minor),
 323                                 "%s%d", "hidraw", minor);
 324
 325         if (IS_ERR(dev->dev)) {
 326                 spin_lock(&minors_lock);
 327                 hidraw_table[minor] = NULL;
 328                 spin_unlock(&minors_lock);
 329                 result = PTR_ERR(dev->dev);
 330                 kfree(dev);
 331                 goto out;
 332         }
 333
 334         init_waitqueue_head(&dev->wait);
 335         INIT_LIST_HEAD(&dev->list);
 336
 337         dev->hid = hid;
 338         dev->minor = minor;
 339
 340         dev->exist = 1;
 341         hid->hidraw = dev;
 342
 343 out:
 344         return result;
 345
 346 }
 347 EXPORT_SYMBOL_GPL(hidraw_connect);
 348
 349 void hidraw_disconnect(struct hid_device *hid)
 350 {
 351         struct hidraw *hidraw = hid->hidraw;
 352
 353         hidraw->exist = 0;
 354
 355         spin_lock(&minors_lock);
 356         hidraw_table[hidraw->minor] = NULL;
 357         spin_unlock(&minors_lock);
 358
 359         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 360
 361         if (hidraw->open) {
 362                 hid->hid_close(hid);
 363                 wake_up_interruptible(&hidraw->wait);
 364         } else {
 365                 kfree(hidraw);
 366         }
 367 }
 368 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 369
 370 int __init hidraw_init(void)
 371 {
 372         int result;
 373         dev_t dev_id;
 374
 375         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 376                         HIDRAW_MAX_DEVICES, "hidraw");
 377
 378         hidraw_major = MAJOR(dev_id);
 379
 380         if (result < 0) {
 381                 printk(KERN_WARNING "hidraw: can't get major number\n");
 382                 result = 0;
 383                 goto out;
 384         }
 385
 386         hidraw_class = class_create(THIS_MODULE, "hidraw");
 387         if (IS_ERR(hidraw_class)) {
 388                 result = PTR_ERR(hidraw_class);
 389                 unregister_chrdev(hidraw_major, "hidraw");
 390                 goto out;
 391         }
 392
 393         cdev_init(&hidraw_cdev, &hidraw_ops);
 394         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 395 out:
 396         return result;
 397 }
 398
 399 void __exit hidraw_exit(void)
 400 {
 401         dev_t dev_id = MKDEV(hidraw_major, 0);
 402
 403         cdev_del(&hidraw_cdev);
 404         class_destroy(hidraw_class);
 405         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 406
 407 }