1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * User-space I/O driver support for HID subsystem 4 * Copyright (c) 2012 David Herrmann 5 */ 6 7 /* 8 */ 9 10 #include <linux/atomic.h> 11 #include <linux/compat.h> 12 #include <linux/cred.h> 13 #include <linux/device.h> 14 #include <linux/fs.h> 15 #include <linux/hid.h> 16 #include <linux/input.h> 17 #include <linux/miscdevice.h> 18 #include <linux/module.h> 19 #include <linux/mutex.h> 20 #include <linux/poll.h> 21 #include <linux/sched.h> 22 #include <linux/spinlock.h> 23 #include <linux/uhid.h> 24 #include <linux/wait.h> 25 26 #define UHID_NAME "uhid" 27 #define UHID_BUFSIZE 32 28 29 struct uhid_device { 30 struct mutex devlock; 31 32 /* This flag tracks whether the HID device is usable for commands from 33 * userspace. The flag is already set before hid_add_device(), which 34 * runs in workqueue context, to allow hid_add_device() to communicate 35 * with userspace. 36 * However, if hid_add_device() fails, the flag is cleared without 37 * holding devlock. 38 * We guarantee that if @running changes from true to false while you're 39 * holding @devlock, it's still fine to access @hid. 40 */ 41 bool running; 42 43 __u8 *rd_data; 44 uint rd_size; 45 46 /* When this is NULL, userspace may use UHID_CREATE/UHID_CREATE2. */ 47 struct hid_device *hid; 48 struct uhid_event input_buf; 49 50 wait_queue_head_t waitq; 51 spinlock_t qlock; 52 __u8 head; 53 __u8 tail; 54 struct uhid_event *outq[UHID_BUFSIZE]; 55 56 /* blocking GET_REPORT support; state changes protected by qlock */ 57 struct mutex report_lock; 58 wait_queue_head_t report_wait; 59 bool report_running; 60 u32 report_id; 61 u32 report_type; 62 struct uhid_event report_buf; 63 struct work_struct worker; 64 }; 65 66 static struct miscdevice uhid_misc; 67 68 static void uhid_device_add_worker(struct work_struct *work) 69 { 70 struct uhid_device *uhid = container_of(work, struct uhid_device, worker); 71 int ret; 72 73 ret = hid_add_device(uhid->hid); 74 if (ret) { 75 hid_err(uhid->hid, "Cannot register HID device: error %d\n", ret); 76 77 /* We used to call hid_destroy_device() here, but that's really 78 * messy to get right because we have to coordinate with 79 * concurrent writes from userspace that might be in the middle 80 * of using uhid->hid. 81 * Just leave uhid->hid as-is for now, and clean it up when 82 * userspace tries to close or reinitialize the uhid instance. 83 * 84 * However, we do have to clear the ->running flag and do a 85 * wakeup to make sure userspace knows that the device is gone. 86 */ 87 WRITE_ONCE(uhid->running, false); 88 wake_up_interruptible(&uhid->report_wait); 89 } 90 } 91 92 static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev) 93 { 94 __u8 newhead; 95 96 newhead = (uhid->head + 1) % UHID_BUFSIZE; 97 98 if (newhead != uhid->tail) { 99 uhid->outq[uhid->head] = ev; 100 uhid->head = newhead; 101 wake_up_interruptible(&uhid->waitq); 102 } else { 103 hid_warn(uhid->hid, "Output queue is full\n"); 104 kfree(ev); 105 } 106 } 107 108 static int uhid_queue_event(struct uhid_device *uhid, __u32 event) 109 { 110 unsigned long flags; 111 struct uhid_event *ev; 112 113 ev = kzalloc(sizeof(*ev), GFP_KERNEL); 114 if (!ev) 115 return -ENOMEM; 116 117 ev->type = event; 118 119 spin_lock_irqsave(&uhid->qlock, flags); 120 uhid_queue(uhid, ev); 121 spin_unlock_irqrestore(&uhid->qlock, flags); 122 123 return 0; 124 } 125 126 static int uhid_hid_start(struct hid_device *hid) 127 { 128 struct uhid_device *uhid = hid->driver_data; 129 struct uhid_event *ev; 130 unsigned long flags; 131 132 ev = kzalloc(sizeof(*ev), GFP_KERNEL); 133 if (!ev) 134 return -ENOMEM; 135 136 ev->type = UHID_START; 137 138 if (hid->report_enum[HID_FEATURE_REPORT].numbered) 139 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_FEATURE_REPORTS; 140 if (hid->report_enum[HID_OUTPUT_REPORT].numbered) 141 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_OUTPUT_REPORTS; 142 if (hid->report_enum[HID_INPUT_REPORT].numbered) 143 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_INPUT_REPORTS; 144 145 spin_lock_irqsave(&uhid->qlock, flags); 146 uhid_queue(uhid, ev); 147 spin_unlock_irqrestore(&uhid->qlock, flags); 148 149 return 0; 150 } 151 152 static void uhid_hid_stop(struct hid_device *hid) 153 { 154 struct uhid_device *uhid = hid->driver_data; 155 156 hid->claimed = 0; 157 uhid_queue_event(uhid, UHID_STOP); 158 } 159 160 static int uhid_hid_open(struct hid_device *hid) 161 { 162 struct uhid_device *uhid = hid->driver_data; 163 164 return uhid_queue_event(uhid, UHID_OPEN); 165 } 166 167 static void uhid_hid_close(struct hid_device *hid) 168 { 169 struct uhid_device *uhid = hid->driver_data; 170 171 uhid_queue_event(uhid, UHID_CLOSE); 172 } 173 174 static int uhid_hid_parse(struct hid_device *hid) 175 { 176 struct uhid_device *uhid = hid->driver_data; 177 178 return hid_parse_report(hid, uhid->rd_data, uhid->rd_size); 179 } 180 181 /* must be called with report_lock held */ 182 static int __uhid_report_queue_and_wait(struct uhid_device *uhid, 183 struct uhid_event *ev, 184 __u32 *report_id) 185 { 186 unsigned long flags; 187 int ret; 188 189 spin_lock_irqsave(&uhid->qlock, flags); 190 *report_id = ++uhid->report_id; 191 uhid->report_type = ev->type + 1; 192 uhid->report_running = true; 193 uhid_queue(uhid, ev); 194 spin_unlock_irqrestore(&uhid->qlock, flags); 195 196 ret = wait_event_interruptible_timeout(uhid->report_wait, 197 !uhid->report_running || !READ_ONCE(uhid->running), 198 5 * HZ); 199 if (!ret || !READ_ONCE(uhid->running) || uhid->report_running) 200 ret = -EIO; 201 else if (ret < 0) 202 ret = -ERESTARTSYS; 203 else 204 ret = 0; 205 206 uhid->report_running = false; 207 208 return ret; 209 } 210 211 static void uhid_report_wake_up(struct uhid_device *uhid, u32 id, 212 const struct uhid_event *ev) 213 { 214 unsigned long flags; 215 216 spin_lock_irqsave(&uhid->qlock, flags); 217 218 /* id for old report; drop it silently */ 219 if (uhid->report_type != ev->type || uhid->report_id != id) 220 goto unlock; 221 if (!uhid->report_running) 222 goto unlock; 223 224 memcpy(&uhid->report_buf, ev, sizeof(*ev)); 225 uhid->report_running = false; 226 wake_up_interruptible(&uhid->report_wait); 227 228 unlock: 229 spin_unlock_irqrestore(&uhid->qlock, flags); 230 } 231 232 static int uhid_hid_get_report(struct hid_device *hid, unsigned char rnum, 233 u8 *buf, size_t count, u8 rtype) 234 { 235 struct uhid_device *uhid = hid->driver_data; 236 struct uhid_get_report_reply_req *req; 237 struct uhid_event *ev; 238 int ret; 239 240 if (!READ_ONCE(uhid->running)) 241 return -EIO; 242 243 ev = kzalloc(sizeof(*ev), GFP_KERNEL); 244 if (!ev) 245 return -ENOMEM; 246 247 ev->type = UHID_GET_REPORT; 248 ev->u.get_report.rnum = rnum; 249 ev->u.get_report.rtype = rtype; 250 251 ret = mutex_lock_interruptible(&uhid->report_lock); 252 if (ret) { 253 kfree(ev); 254 return ret; 255 } 256 257 /* this _always_ takes ownership of @ev */ 258 ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.get_report.id); 259 if (ret) 260 goto unlock; 261 262 req = &uhid->report_buf.u.get_report_reply; 263 if (req->err) { 264 ret = -EIO; 265 } else { 266 ret = min3(count, (size_t)req->size, (size_t)UHID_DATA_MAX); 267 memcpy(buf, req->data, ret); 268 } 269 270 unlock: 271 mutex_unlock(&uhid->report_lock); 272 return ret; 273 } 274 275 static int uhid_hid_set_report(struct hid_device *hid, unsigned char rnum, 276 const u8 *buf, size_t count, u8 rtype) 277 { 278 struct uhid_device *uhid = hid->driver_data; 279 struct uhid_event *ev; 280 int ret; 281 282 if (!READ_ONCE(uhid->running) || count > UHID_DATA_MAX) 283 return -EIO; 284 285 ev = kzalloc(sizeof(*ev), GFP_KERNEL); 286 if (!ev) 287 return -ENOMEM; 288 289 ev->type = UHID_SET_REPORT; 290 ev->u.set_report.rnum = rnum; 291 ev->u.set_report.rtype = rtype; 292 ev->u.set_report.size = count; 293 memcpy(ev->u.set_report.data, buf, count); 294 295 ret = mutex_lock_interruptible(&uhid->report_lock); 296 if (ret) { 297 kfree(ev); 298 return ret; 299 } 300 301 /* this _always_ takes ownership of @ev */ 302 ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.set_report.id); 303 if (ret) 304 goto unlock; 305 306 if (uhid->report_buf.u.set_report_reply.err) 307 ret = -EIO; 308 else 309 ret = count; 310 311 unlock: 312 mutex_unlock(&uhid->report_lock); 313 return ret; 314 } 315 316 static int uhid_hid_raw_request(struct hid_device *hid, unsigned char reportnum, 317 __u8 *buf, size_t len, unsigned char rtype, 318 int reqtype) 319 { 320 u8 u_rtype; 321 322 switch (rtype) { 323 case HID_FEATURE_REPORT: 324 u_rtype = UHID_FEATURE_REPORT; 325 break; 326 case HID_OUTPUT_REPORT: 327 u_rtype = UHID_OUTPUT_REPORT; 328 break; 329 case HID_INPUT_REPORT: 330 u_rtype = UHID_INPUT_REPORT; 331 break; 332 default: 333 return -EINVAL; 334 } 335 336 switch (reqtype) { 337 case HID_REQ_GET_REPORT: 338 return uhid_hid_get_report(hid, reportnum, buf, len, u_rtype); 339 case HID_REQ_SET_REPORT: 340 return uhid_hid_set_report(hid, reportnum, buf, len, u_rtype); 341 default: 342 return -EIO; 343 } 344 } 345 346 static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count, 347 unsigned char report_type) 348 { 349 struct uhid_device *uhid = hid->driver_data; 350 __u8 rtype; 351 unsigned long flags; 352 struct uhid_event *ev; 353 354 switch (report_type) { 355 case HID_FEATURE_REPORT: 356 rtype = UHID_FEATURE_REPORT; 357 break; 358 case HID_OUTPUT_REPORT: 359 rtype = UHID_OUTPUT_REPORT; 360 break; 361 default: 362 return -EINVAL; 363 } 364 365 if (count < 1 || count > UHID_DATA_MAX) 366 return -EINVAL; 367 368 ev = kzalloc(sizeof(*ev), GFP_KERNEL); 369 if (!ev) 370 return -ENOMEM; 371 372 ev->type = UHID_OUTPUT; 373 ev->u.output.size = count; 374 ev->u.output.rtype = rtype; 375 memcpy(ev->u.output.data, buf, count); 376 377 spin_lock_irqsave(&uhid->qlock, flags); 378 uhid_queue(uhid, ev); 379 spin_unlock_irqrestore(&uhid->qlock, flags); 380 381 return count; 382 } 383 384 static int uhid_hid_output_report(struct hid_device *hid, __u8 *buf, 385 size_t count) 386 { 387 return uhid_hid_output_raw(hid, buf, count, HID_OUTPUT_REPORT); 388 } 389 390 static const struct hid_ll_driver uhid_hid_driver = { 391 .start = uhid_hid_start, 392 .stop = uhid_hid_stop, 393 .open = uhid_hid_open, 394 .close = uhid_hid_close, 395 .parse = uhid_hid_parse, 396 .raw_request = uhid_hid_raw_request, 397 .output_report = uhid_hid_output_report, 398 .max_buffer_size = UHID_DATA_MAX, 399 }; 400 401 #ifdef CONFIG_COMPAT 402 403 /* Apparently we haven't stepped on these rakes enough times yet. */ 404 struct uhid_create_req_compat { 405 __u8 name[128]; 406 __u8 phys[64]; 407 __u8 uniq[64]; 408 409 compat_uptr_t rd_data; 410 __u16 rd_size; 411 412 __u16 bus; 413 __u32 vendor; 414 __u32 product; 415 __u32 version; 416 __u32 country; 417 } __attribute__((__packed__)); 418 419 static int uhid_event_from_user(const char __user *buffer, size_t len, 420 struct uhid_event *event) 421 { 422 if (in_compat_syscall()) { 423 u32 type; 424 425 if (get_user(type, buffer)) 426 return -EFAULT; 427 428 if (type == UHID_CREATE) { 429 /* 430 * This is our messed up request with compat pointer. 431 * It is largish (more than 256 bytes) so we better 432 * allocate it from the heap. 433 */ 434 struct uhid_create_req_compat *compat; 435 436 compat = kzalloc(sizeof(*compat), GFP_KERNEL); 437 if (!compat) 438 return -ENOMEM; 439 440 buffer += sizeof(type); 441 len -= sizeof(type); 442 if (copy_from_user(compat, buffer, 443 min(len, sizeof(*compat)))) { 444 kfree(compat); 445 return -EFAULT; 446 } 447 448 /* Shuffle the data over to proper structure */ 449 event->type = type; 450 451 memcpy(event->u.create.name, compat->name, 452 sizeof(compat->name)); 453 memcpy(event->u.create.phys, compat->phys, 454 sizeof(compat->phys)); 455 memcpy(event->u.create.uniq, compat->uniq, 456 sizeof(compat->uniq)); 457 458 event->u.create.rd_data = compat_ptr(compat->rd_data); 459 event->u.create.rd_size = compat->rd_size; 460 461 event->u.create.bus = compat->bus; 462 event->u.create.vendor = compat->vendor; 463 event->u.create.product = compat->product; 464 event->u.create.version = compat->version; 465 event->u.create.country = compat->country; 466 467 kfree(compat); 468 return 0; 469 } 470 /* All others can be copied directly */ 471 } 472 473 if (copy_from_user(event, buffer, min(len, sizeof(*event)))) 474 return -EFAULT; 475 476 return 0; 477 } 478 #else 479 static int uhid_event_from_user(const char __user *buffer, size_t len, 480 struct uhid_event *event) 481 { 482 if (copy_from_user(event, buffer, min(len, sizeof(*event)))) 483 return -EFAULT; 484 485 return 0; 486 } 487 #endif 488 489 static int uhid_dev_create2(struct uhid_device *uhid, 490 const struct uhid_event *ev) 491 { 492 struct hid_device *hid; 493 size_t rd_size; 494 void *rd_data; 495 int ret; 496 497 if (uhid->hid) 498 return -EALREADY; 499 500 rd_size = ev->u.create2.rd_size; 501 if (rd_size <= 0 || rd_size > HID_MAX_DESCRIPTOR_SIZE) 502 return -EINVAL; 503 504 rd_data = kmemdup(ev->u.create2.rd_data, rd_size, GFP_KERNEL); 505 if (!rd_data) 506 return -ENOMEM; 507 508 uhid->rd_size = rd_size; 509 uhid->rd_data = rd_data; 510 511 hid = hid_allocate_device(); 512 if (IS_ERR(hid)) { 513 ret = PTR_ERR(hid); 514 goto err_free; 515 } 516 517 BUILD_BUG_ON(sizeof(hid->name) != sizeof(ev->u.create2.name)); 518 strscpy(hid->name, ev->u.create2.name, sizeof(hid->name)); 519 BUILD_BUG_ON(sizeof(hid->phys) != sizeof(ev->u.create2.phys)); 520 strscpy(hid->phys, ev->u.create2.phys, sizeof(hid->phys)); 521 BUILD_BUG_ON(sizeof(hid->uniq) != sizeof(ev->u.create2.uniq)); 522 strscpy(hid->uniq, ev->u.create2.uniq, sizeof(hid->uniq)); 523 524 hid->ll_driver = &uhid_hid_driver; 525 hid->bus = ev->u.create2.bus; 526 hid->vendor = ev->u.create2.vendor; 527 hid->product = ev->u.create2.product; 528 hid->version = ev->u.create2.version; 529 hid->country = ev->u.create2.country; 530 hid->driver_data = uhid; 531 hid->dev.parent = uhid_misc.this_device; 532 533 uhid->hid = hid; 534 uhid->running = true; 535 536 /* Adding of a HID device is done through a worker, to allow HID drivers 537 * which use feature requests during .probe to work, without they would 538 * be blocked on devlock, which is held by uhid_char_write. 539 */ 540 schedule_work(&uhid->worker); 541 542 return 0; 543 544 err_free: 545 kfree(uhid->rd_data); 546 uhid->rd_data = NULL; 547 uhid->rd_size = 0; 548 return ret; 549 } 550 551 static int uhid_dev_create(struct uhid_device *uhid, 552 struct uhid_event *ev) 553 { 554 struct uhid_create_req orig; 555 556 orig = ev->u.create; 557 558 if (orig.rd_size <= 0 || orig.rd_size > HID_MAX_DESCRIPTOR_SIZE) 559 return -EINVAL; 560 if (copy_from_user(&ev->u.create2.rd_data, orig.rd_data, orig.rd_size)) 561 return -EFAULT; 562 563 memcpy(ev->u.create2.name, orig.name, sizeof(orig.name)); 564 memcpy(ev->u.create2.phys, orig.phys, sizeof(orig.phys)); 565 memcpy(ev->u.create2.uniq, orig.uniq, sizeof(orig.uniq)); 566 ev->u.create2.rd_size = orig.rd_size; 567 ev->u.create2.bus = orig.bus; 568 ev->u.create2.vendor = orig.vendor; 569 ev->u.create2.product = orig.product; 570 ev->u.create2.version = orig.version; 571 ev->u.create2.country = orig.country; 572 573 return uhid_dev_create2(uhid, ev); 574 } 575 576 static int uhid_dev_destroy(struct uhid_device *uhid) 577 { 578 if (!uhid->hid) 579 return -EINVAL; 580 581 WRITE_ONCE(uhid->running, false); 582 wake_up_interruptible(&uhid->report_wait); 583 584 cancel_work_sync(&uhid->worker); 585 586 hid_destroy_device(uhid->hid); 587 uhid->hid = NULL; 588 kfree(uhid->rd_data); 589 590 return 0; 591 } 592 593 static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev) 594 { 595 if (!READ_ONCE(uhid->running)) 596 return -EINVAL; 597 598 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data, 599 min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0); 600 601 return 0; 602 } 603 604 static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev) 605 { 606 if (!READ_ONCE(uhid->running)) 607 return -EINVAL; 608 609 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data, 610 min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0); 611 612 return 0; 613 } 614 615 static int uhid_dev_get_report_reply(struct uhid_device *uhid, 616 struct uhid_event *ev) 617 { 618 if (!READ_ONCE(uhid->running)) 619 return -EINVAL; 620 621 uhid_report_wake_up(uhid, ev->u.get_report_reply.id, ev); 622 return 0; 623 } 624 625 static int uhid_dev_set_report_reply(struct uhid_device *uhid, 626 struct uhid_event *ev) 627 { 628 if (!READ_ONCE(uhid->running)) 629 return -EINVAL; 630 631 uhid_report_wake_up(uhid, ev->u.set_report_reply.id, ev); 632 return 0; 633 } 634 635 static int uhid_char_open(struct inode *inode, struct file *file) 636 { 637 struct uhid_device *uhid; 638 639 uhid = kzalloc(sizeof(*uhid), GFP_KERNEL); 640 if (!uhid) 641 return -ENOMEM; 642 643 mutex_init(&uhid->devlock); 644 mutex_init(&uhid->report_lock); 645 spin_lock_init(&uhid->qlock); 646 init_waitqueue_head(&uhid->waitq); 647 init_waitqueue_head(&uhid->report_wait); 648 uhid->running = false; 649 INIT_WORK(&uhid->worker, uhid_device_add_worker); 650 651 file->private_data = uhid; 652 stream_open(inode, file); 653 654 return 0; 655 } 656 657 static int uhid_char_release(struct inode *inode, struct file *file) 658 { 659 struct uhid_device *uhid = file->private_data; 660 unsigned int i; 661 662 uhid_dev_destroy(uhid); 663 664 for (i = 0; i < UHID_BUFSIZE; ++i) 665 kfree(uhid->outq[i]); 666 667 kfree(uhid); 668 669 return 0; 670 } 671 672 static ssize_t uhid_char_read(struct file *file, char __user *buffer, 673 size_t count, loff_t *ppos) 674 { 675 struct uhid_device *uhid = file->private_data; 676 int ret; 677 unsigned long flags; 678 size_t len; 679 680 /* they need at least the "type" member of uhid_event */ 681 if (count < sizeof(__u32)) 682 return -EINVAL; 683 684 try_again: 685 if (file->f_flags & O_NONBLOCK) { 686 if (uhid->head == uhid->tail) 687 return -EAGAIN; 688 } else { 689 ret = wait_event_interruptible(uhid->waitq, 690 uhid->head != uhid->tail); 691 if (ret) 692 return ret; 693 } 694 695 ret = mutex_lock_interruptible(&uhid->devlock); 696 if (ret) 697 return ret; 698 699 if (uhid->head == uhid->tail) { 700 mutex_unlock(&uhid->devlock); 701 goto try_again; 702 } else { 703 len = min(count, sizeof(**uhid->outq)); 704 if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) { 705 ret = -EFAULT; 706 } else { 707 kfree(uhid->outq[uhid->tail]); 708 uhid->outq[uhid->tail] = NULL; 709 710 spin_lock_irqsave(&uhid->qlock, flags); 711 uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE; 712 spin_unlock_irqrestore(&uhid->qlock, flags); 713 } 714 } 715 716 mutex_unlock(&uhid->devlock); 717 return ret ? ret : len; 718 } 719 720 static ssize_t uhid_char_write(struct file *file, const char __user *buffer, 721 size_t count, loff_t *ppos) 722 { 723 struct uhid_device *uhid = file->private_data; 724 int ret; 725 size_t len; 726 727 /* we need at least the "type" member of uhid_event */ 728 if (count < sizeof(__u32)) 729 return -EINVAL; 730 731 ret = mutex_lock_interruptible(&uhid->devlock); 732 if (ret) 733 return ret; 734 735 memset(&uhid->input_buf, 0, sizeof(uhid->input_buf)); 736 len = min(count, sizeof(uhid->input_buf)); 737 738 ret = uhid_event_from_user(buffer, len, &uhid->input_buf); 739 if (ret) 740 goto unlock; 741 742 switch (uhid->input_buf.type) { 743 case UHID_CREATE: 744 /* 745 * 'struct uhid_create_req' contains a __user pointer which is 746 * copied from, so it's unsafe to allow this with elevated 747 * privileges (e.g. from a setuid binary) or via kernel_write(). 748 */ 749 if (file->f_cred != current_cred()) { 750 pr_err_once("UHID_CREATE from different security context by process %d (%s), this is not allowed.\n", 751 task_tgid_vnr(current), current->comm); 752 ret = -EACCES; 753 goto unlock; 754 } 755 ret = uhid_dev_create(uhid, &uhid->input_buf); 756 break; 757 case UHID_CREATE2: 758 ret = uhid_dev_create2(uhid, &uhid->input_buf); 759 break; 760 case UHID_DESTROY: 761 ret = uhid_dev_destroy(uhid); 762 break; 763 case UHID_INPUT: 764 ret = uhid_dev_input(uhid, &uhid->input_buf); 765 break; 766 case UHID_INPUT2: 767 ret = uhid_dev_input2(uhid, &uhid->input_buf); 768 break; 769 case UHID_GET_REPORT_REPLY: 770 ret = uhid_dev_get_report_reply(uhid, &uhid->input_buf); 771 break; 772 case UHID_SET_REPORT_REPLY: 773 ret = uhid_dev_set_report_reply(uhid, &uhid->input_buf); 774 break; 775 default: 776 ret = -EOPNOTSUPP; 777 } 778 779 unlock: 780 mutex_unlock(&uhid->devlock); 781 782 /* return "count" not "len" to not confuse the caller */ 783 return ret ? ret : count; 784 } 785 786 static __poll_t uhid_char_poll(struct file *file, poll_table *wait) 787 { 788 struct uhid_device *uhid = file->private_data; 789 __poll_t mask = EPOLLOUT | EPOLLWRNORM; /* uhid is always writable */ 790 791 poll_wait(file, &uhid->waitq, wait); 792 793 if (uhid->head != uhid->tail) 794 mask |= EPOLLIN | EPOLLRDNORM; 795 796 return mask; 797 } 798 799 static const struct file_operations uhid_fops = { 800 .owner = THIS_MODULE, 801 .open = uhid_char_open, 802 .release = uhid_char_release, 803 .read = uhid_char_read, 804 .write = uhid_char_write, 805 .poll = uhid_char_poll, 806 .llseek = no_llseek, 807 }; 808 809 static struct miscdevice uhid_misc = { 810 .fops = &uhid_fops, 811 .minor = UHID_MINOR, 812 .name = UHID_NAME, 813 }; 814 module_misc_device(uhid_misc); 815 816 MODULE_LICENSE("GPL"); 817 MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>"); 818 MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem"); 819 MODULE_ALIAS_MISCDEV(UHID_MINOR); 820 MODULE_ALIAS("devname:" UHID_NAME); 821