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 #include <linux/sched.h> 34 #include <linux/smp_lock.h> 35 36 #include <linux/hidraw.h> 37 38 static int hidraw_major; 39 static struct cdev hidraw_cdev; 40 static struct class *hidraw_class; 41 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES]; 42 static DEFINE_MUTEX(minors_lock); 43 44 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos) 45 { 46 struct hidraw_list *list = file->private_data; 47 int ret = 0, len; 48 char *report; 49 DECLARE_WAITQUEUE(wait, current); 50 51 while (ret == 0) { 52 53 mutex_lock(&list->read_mutex); 54 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); 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 } 463