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 38 #include <linux/hidraw.h> 39 40 static int hidraw_major; 41 static struct cdev hidraw_cdev; 42 static struct class *hidraw_class; 43 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES]; 44 static DEFINE_MUTEX(minors_lock); 45 46 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos) 47 { 48 struct hidraw_list *list = file->private_data; 49 int ret = 0, len; 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 len = list->buffer[list->tail].len > count ? 88 count : list->buffer[list->tail].len; 89 90 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) { 91 ret = -EFAULT; 92 goto out; 93 } 94 ret += len; 95 96 kfree(list->buffer[list->tail].value); 97 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1); 98 } 99 out: 100 mutex_unlock(&list->read_mutex); 101 return ret; 102 } 103 104 /* the first byte is expected to be a report number */ 105 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) 106 { 107 unsigned int minor = iminor(file->f_path.dentry->d_inode); 108 struct hid_device *dev; 109 __u8 *buf; 110 int ret = 0; 111 112 mutex_lock(&minors_lock); 113 114 if (!hidraw_table[minor]) { 115 ret = -ENODEV; 116 goto out; 117 } 118 119 dev = hidraw_table[minor]->hid; 120 121 if (!dev->hid_output_raw_report) { 122 ret = -ENODEV; 123 goto out; 124 } 125 126 if (count > HID_MAX_BUFFER_SIZE) { 127 hid_warn(dev, "pid %d passed too large report\n", 128 task_pid_nr(current)); 129 ret = -EINVAL; 130 goto out; 131 } 132 133 if (count < 2) { 134 hid_warn(dev, "pid %d passed too short report\n", 135 task_pid_nr(current)); 136 ret = -EINVAL; 137 goto out; 138 } 139 140 buf = kmalloc(count * sizeof(__u8), GFP_KERNEL); 141 if (!buf) { 142 ret = -ENOMEM; 143 goto out; 144 } 145 146 if (copy_from_user(buf, buffer, count)) { 147 ret = -EFAULT; 148 goto out_free; 149 } 150 151 ret = dev->hid_output_raw_report(dev, buf, count, HID_OUTPUT_REPORT); 152 out_free: 153 kfree(buf); 154 out: 155 mutex_unlock(&minors_lock); 156 return ret; 157 } 158 159 static unsigned int hidraw_poll(struct file *file, poll_table *wait) 160 { 161 struct hidraw_list *list = file->private_data; 162 163 poll_wait(file, &list->hidraw->wait, wait); 164 if (list->head != list->tail) 165 return POLLIN | POLLRDNORM; 166 if (!list->hidraw->exist) 167 return POLLERR | POLLHUP; 168 return 0; 169 } 170 171 static int hidraw_open(struct inode *inode, struct file *file) 172 { 173 unsigned int minor = iminor(inode); 174 struct hidraw *dev; 175 struct hidraw_list *list; 176 int err = 0; 177 178 if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) { 179 err = -ENOMEM; 180 goto out; 181 } 182 183 mutex_lock(&minors_lock); 184 if (!hidraw_table[minor]) { 185 kfree(list); 186 err = -ENODEV; 187 goto out_unlock; 188 } 189 190 list->hidraw = hidraw_table[minor]; 191 mutex_init(&list->read_mutex); 192 list_add_tail(&list->node, &hidraw_table[minor]->list); 193 file->private_data = list; 194 195 dev = hidraw_table[minor]; 196 if (!dev->open++) { 197 err = hid_hw_power(dev->hid, PM_HINT_FULLON); 198 if (err < 0) 199 goto out_unlock; 200 201 err = hid_hw_open(dev->hid); 202 if (err < 0) { 203 hid_hw_power(dev->hid, PM_HINT_NORMAL); 204 dev->open--; 205 } 206 } 207 208 out_unlock: 209 mutex_unlock(&minors_lock); 210 out: 211 return err; 212 213 } 214 215 static int hidraw_release(struct inode * inode, struct file * file) 216 { 217 unsigned int minor = iminor(inode); 218 struct hidraw *dev; 219 struct hidraw_list *list = file->private_data; 220 int ret; 221 222 mutex_lock(&minors_lock); 223 if (!hidraw_table[minor]) { 224 ret = -ENODEV; 225 goto unlock; 226 } 227 228 list_del(&list->node); 229 dev = hidraw_table[minor]; 230 if (!--dev->open) { 231 if (list->hidraw->exist) { 232 hid_hw_power(dev->hid, PM_HINT_NORMAL); 233 hid_hw_close(dev->hid); 234 } else { 235 kfree(list->hidraw); 236 } 237 } 238 kfree(list); 239 ret = 0; 240 unlock: 241 mutex_unlock(&minors_lock); 242 243 return ret; 244 } 245 246 static long hidraw_ioctl(struct file *file, unsigned int cmd, 247 unsigned long arg) 248 { 249 struct inode *inode = file->f_path.dentry->d_inode; 250 unsigned int minor = iminor(inode); 251 long ret = 0; 252 struct hidraw *dev; 253 void __user *user_arg = (void __user*) arg; 254 255 mutex_lock(&minors_lock); 256 dev = hidraw_table[minor]; 257 if (!dev) { 258 ret = -ENODEV; 259 goto out; 260 } 261 262 switch (cmd) { 263 case HIDIOCGRDESCSIZE: 264 if (put_user(dev->hid->rsize, (int __user *)arg)) 265 ret = -EFAULT; 266 break; 267 268 case HIDIOCGRDESC: 269 { 270 __u32 len; 271 272 if (get_user(len, (int __user *)arg)) 273 ret = -EFAULT; 274 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1) 275 ret = -EINVAL; 276 else if (copy_to_user(user_arg + offsetof( 277 struct hidraw_report_descriptor, 278 value[0]), 279 dev->hid->rdesc, 280 min(dev->hid->rsize, len))) 281 ret = -EFAULT; 282 break; 283 } 284 case HIDIOCGRAWINFO: 285 { 286 struct hidraw_devinfo dinfo; 287 288 dinfo.bustype = dev->hid->bus; 289 dinfo.vendor = dev->hid->vendor; 290 dinfo.product = dev->hid->product; 291 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo))) 292 ret = -EFAULT; 293 break; 294 } 295 default: 296 { 297 struct hid_device *hid = dev->hid; 298 if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ) { 299 ret = -EINVAL; 300 break; 301 } 302 303 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) { 304 int len; 305 if (!hid->name) { 306 ret = 0; 307 break; 308 } 309 len = strlen(hid->name) + 1; 310 if (len > _IOC_SIZE(cmd)) 311 len = _IOC_SIZE(cmd); 312 ret = copy_to_user(user_arg, hid->name, len) ? 313 -EFAULT : len; 314 break; 315 } 316 317 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) { 318 int len; 319 if (!hid->phys) { 320 ret = 0; 321 break; 322 } 323 len = strlen(hid->phys) + 1; 324 if (len > _IOC_SIZE(cmd)) 325 len = _IOC_SIZE(cmd); 326 ret = copy_to_user(user_arg, hid->phys, len) ? 327 -EFAULT : len; 328 break; 329 } 330 } 331 332 ret = -ENOTTY; 333 } 334 out: 335 mutex_unlock(&minors_lock); 336 return ret; 337 } 338 339 static const struct file_operations hidraw_ops = { 340 .owner = THIS_MODULE, 341 .read = hidraw_read, 342 .write = hidraw_write, 343 .poll = hidraw_poll, 344 .open = hidraw_open, 345 .release = hidraw_release, 346 .unlocked_ioctl = hidraw_ioctl, 347 #ifdef CONFIG_COMPAT 348 .compat_ioctl = hidraw_ioctl, 349 #endif 350 .llseek = noop_llseek, 351 }; 352 353 void hidraw_report_event(struct hid_device *hid, u8 *data, int len) 354 { 355 struct hidraw *dev = hid->hidraw; 356 struct hidraw_list *list; 357 358 list_for_each_entry(list, &dev->list, node) { 359 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC); 360 list->buffer[list->head].len = len; 361 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1); 362 kill_fasync(&list->fasync, SIGIO, POLL_IN); 363 } 364 365 wake_up_interruptible(&dev->wait); 366 } 367 EXPORT_SYMBOL_GPL(hidraw_report_event); 368 369 int hidraw_connect(struct hid_device *hid) 370 { 371 int minor, result; 372 struct hidraw *dev; 373 374 /* we accept any HID device, no matter the applications */ 375 376 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL); 377 if (!dev) 378 return -ENOMEM; 379 380 result = -EINVAL; 381 382 mutex_lock(&minors_lock); 383 384 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) { 385 if (hidraw_table[minor]) 386 continue; 387 hidraw_table[minor] = dev; 388 result = 0; 389 break; 390 } 391 392 if (result) { 393 mutex_unlock(&minors_lock); 394 kfree(dev); 395 goto out; 396 } 397 398 dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor), 399 NULL, "%s%d", "hidraw", minor); 400 401 if (IS_ERR(dev->dev)) { 402 hidraw_table[minor] = NULL; 403 mutex_unlock(&minors_lock); 404 result = PTR_ERR(dev->dev); 405 kfree(dev); 406 goto out; 407 } 408 409 mutex_unlock(&minors_lock); 410 init_waitqueue_head(&dev->wait); 411 INIT_LIST_HEAD(&dev->list); 412 413 dev->hid = hid; 414 dev->minor = minor; 415 416 dev->exist = 1; 417 hid->hidraw = dev; 418 419 out: 420 return result; 421 422 } 423 EXPORT_SYMBOL_GPL(hidraw_connect); 424 425 void hidraw_disconnect(struct hid_device *hid) 426 { 427 struct hidraw *hidraw = hid->hidraw; 428 429 hidraw->exist = 0; 430 431 mutex_lock(&minors_lock); 432 hidraw_table[hidraw->minor] = NULL; 433 mutex_unlock(&minors_lock); 434 435 device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor)); 436 437 if (hidraw->open) { 438 hid_hw_close(hid); 439 wake_up_interruptible(&hidraw->wait); 440 } else { 441 kfree(hidraw); 442 } 443 } 444 EXPORT_SYMBOL_GPL(hidraw_disconnect); 445 446 int __init hidraw_init(void) 447 { 448 int result; 449 dev_t dev_id; 450 451 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR, 452 HIDRAW_MAX_DEVICES, "hidraw"); 453 454 hidraw_major = MAJOR(dev_id); 455 456 if (result < 0) { 457 pr_warn("can't get major number\n"); 458 result = 0; 459 goto out; 460 } 461 462 hidraw_class = class_create(THIS_MODULE, "hidraw"); 463 if (IS_ERR(hidraw_class)) { 464 result = PTR_ERR(hidraw_class); 465 unregister_chrdev(hidraw_major, "hidraw"); 466 goto out; 467 } 468 469 cdev_init(&hidraw_cdev, &hidraw_ops); 470 cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES); 471 out: 472 return result; 473 } 474 475 void hidraw_exit(void) 476 { 477 dev_t dev_id = MKDEV(hidraw_major, 0); 478 479 cdev_del(&hidraw_cdev); 480 class_destroy(hidraw_class); 481 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 482 483 } 484