1 /* 2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited. 3 * Copyright (C) 2004 - 2006 Red Hat, Inc. All rights reserved. 4 * 5 * This file is released under the GPL. 6 */ 7 8 #include "dm.h" 9 10 #include <linux/module.h> 11 #include <linux/vmalloc.h> 12 #include <linux/miscdevice.h> 13 #include <linux/init.h> 14 #include <linux/wait.h> 15 #include <linux/slab.h> 16 #include <linux/dm-ioctl.h> 17 #include <linux/hdreg.h> 18 #include <linux/compat.h> 19 20 #include <asm/uaccess.h> 21 22 #define DM_MSG_PREFIX "ioctl" 23 #define DM_DRIVER_EMAIL "dm-devel@redhat.com" 24 25 /*----------------------------------------------------------------- 26 * The ioctl interface needs to be able to look up devices by 27 * name or uuid. 28 *---------------------------------------------------------------*/ 29 struct hash_cell { 30 struct list_head name_list; 31 struct list_head uuid_list; 32 33 char *name; 34 char *uuid; 35 struct mapped_device *md; 36 struct dm_table *new_map; 37 }; 38 39 struct vers_iter { 40 size_t param_size; 41 struct dm_target_versions *vers, *old_vers; 42 char *end; 43 uint32_t flags; 44 }; 45 46 47 #define NUM_BUCKETS 64 48 #define MASK_BUCKETS (NUM_BUCKETS - 1) 49 static struct list_head _name_buckets[NUM_BUCKETS]; 50 static struct list_head _uuid_buckets[NUM_BUCKETS]; 51 52 static void dm_hash_remove_all(int keep_open_devices); 53 54 /* 55 * Guards access to both hash tables. 56 */ 57 static DECLARE_RWSEM(_hash_lock); 58 59 static void init_buckets(struct list_head *buckets) 60 { 61 unsigned int i; 62 63 for (i = 0; i < NUM_BUCKETS; i++) 64 INIT_LIST_HEAD(buckets + i); 65 } 66 67 static int dm_hash_init(void) 68 { 69 init_buckets(_name_buckets); 70 init_buckets(_uuid_buckets); 71 return 0; 72 } 73 74 static void dm_hash_exit(void) 75 { 76 dm_hash_remove_all(0); 77 } 78 79 /*----------------------------------------------------------------- 80 * Hash function: 81 * We're not really concerned with the str hash function being 82 * fast since it's only used by the ioctl interface. 83 *---------------------------------------------------------------*/ 84 static unsigned int hash_str(const char *str) 85 { 86 const unsigned int hash_mult = 2654435387U; 87 unsigned int h = 0; 88 89 while (*str) 90 h = (h + (unsigned int) *str++) * hash_mult; 91 92 return h & MASK_BUCKETS; 93 } 94 95 /*----------------------------------------------------------------- 96 * Code for looking up a device by name 97 *---------------------------------------------------------------*/ 98 static struct hash_cell *__get_name_cell(const char *str) 99 { 100 struct hash_cell *hc; 101 unsigned int h = hash_str(str); 102 103 list_for_each_entry (hc, _name_buckets + h, name_list) 104 if (!strcmp(hc->name, str)) { 105 dm_get(hc->md); 106 return hc; 107 } 108 109 return NULL; 110 } 111 112 static struct hash_cell *__get_uuid_cell(const char *str) 113 { 114 struct hash_cell *hc; 115 unsigned int h = hash_str(str); 116 117 list_for_each_entry (hc, _uuid_buckets + h, uuid_list) 118 if (!strcmp(hc->uuid, str)) { 119 dm_get(hc->md); 120 return hc; 121 } 122 123 return NULL; 124 } 125 126 /*----------------------------------------------------------------- 127 * Inserting, removing and renaming a device. 128 *---------------------------------------------------------------*/ 129 static struct hash_cell *alloc_cell(const char *name, const char *uuid, 130 struct mapped_device *md) 131 { 132 struct hash_cell *hc; 133 134 hc = kmalloc(sizeof(*hc), GFP_KERNEL); 135 if (!hc) 136 return NULL; 137 138 hc->name = kstrdup(name, GFP_KERNEL); 139 if (!hc->name) { 140 kfree(hc); 141 return NULL; 142 } 143 144 if (!uuid) 145 hc->uuid = NULL; 146 147 else { 148 hc->uuid = kstrdup(uuid, GFP_KERNEL); 149 if (!hc->uuid) { 150 kfree(hc->name); 151 kfree(hc); 152 return NULL; 153 } 154 } 155 156 INIT_LIST_HEAD(&hc->name_list); 157 INIT_LIST_HEAD(&hc->uuid_list); 158 hc->md = md; 159 hc->new_map = NULL; 160 return hc; 161 } 162 163 static void free_cell(struct hash_cell *hc) 164 { 165 if (hc) { 166 kfree(hc->name); 167 kfree(hc->uuid); 168 kfree(hc); 169 } 170 } 171 172 /* 173 * The kdev_t and uuid of a device can never change once it is 174 * initially inserted. 175 */ 176 static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md) 177 { 178 struct hash_cell *cell, *hc; 179 180 /* 181 * Allocate the new cells. 182 */ 183 cell = alloc_cell(name, uuid, md); 184 if (!cell) 185 return -ENOMEM; 186 187 /* 188 * Insert the cell into both hash tables. 189 */ 190 down_write(&_hash_lock); 191 hc = __get_name_cell(name); 192 if (hc) { 193 dm_put(hc->md); 194 goto bad; 195 } 196 197 list_add(&cell->name_list, _name_buckets + hash_str(name)); 198 199 if (uuid) { 200 hc = __get_uuid_cell(uuid); 201 if (hc) { 202 list_del(&cell->name_list); 203 dm_put(hc->md); 204 goto bad; 205 } 206 list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid)); 207 } 208 dm_get(md); 209 dm_set_mdptr(md, cell); 210 up_write(&_hash_lock); 211 212 return 0; 213 214 bad: 215 up_write(&_hash_lock); 216 free_cell(cell); 217 return -EBUSY; 218 } 219 220 static void __hash_remove(struct hash_cell *hc) 221 { 222 struct dm_table *table; 223 224 /* remove from the dev hash */ 225 list_del(&hc->uuid_list); 226 list_del(&hc->name_list); 227 dm_set_mdptr(hc->md, NULL); 228 229 table = dm_get_table(hc->md); 230 if (table) { 231 dm_table_event(table); 232 dm_table_put(table); 233 } 234 235 if (hc->new_map) 236 dm_table_put(hc->new_map); 237 dm_put(hc->md); 238 free_cell(hc); 239 } 240 241 static void dm_hash_remove_all(int keep_open_devices) 242 { 243 int i, dev_skipped, dev_removed; 244 struct hash_cell *hc; 245 struct list_head *tmp, *n; 246 247 down_write(&_hash_lock); 248 249 retry: 250 dev_skipped = dev_removed = 0; 251 for (i = 0; i < NUM_BUCKETS; i++) { 252 list_for_each_safe (tmp, n, _name_buckets + i) { 253 hc = list_entry(tmp, struct hash_cell, name_list); 254 255 if (keep_open_devices && 256 dm_lock_for_deletion(hc->md)) { 257 dev_skipped++; 258 continue; 259 } 260 __hash_remove(hc); 261 dev_removed = 1; 262 } 263 } 264 265 /* 266 * Some mapped devices may be using other mapped devices, so if any 267 * still exist, repeat until we make no further progress. 268 */ 269 if (dev_skipped) { 270 if (dev_removed) 271 goto retry; 272 273 DMWARN("remove_all left %d open device(s)", dev_skipped); 274 } 275 276 up_write(&_hash_lock); 277 } 278 279 static int dm_hash_rename(const char *old, const char *new) 280 { 281 char *new_name, *old_name; 282 struct hash_cell *hc; 283 struct dm_table *table; 284 285 /* 286 * duplicate new. 287 */ 288 new_name = kstrdup(new, GFP_KERNEL); 289 if (!new_name) 290 return -ENOMEM; 291 292 down_write(&_hash_lock); 293 294 /* 295 * Is new free ? 296 */ 297 hc = __get_name_cell(new); 298 if (hc) { 299 DMWARN("asked to rename to an already existing name %s -> %s", 300 old, new); 301 dm_put(hc->md); 302 up_write(&_hash_lock); 303 kfree(new_name); 304 return -EBUSY; 305 } 306 307 /* 308 * Is there such a device as 'old' ? 309 */ 310 hc = __get_name_cell(old); 311 if (!hc) { 312 DMWARN("asked to rename a non existent device %s -> %s", 313 old, new); 314 up_write(&_hash_lock); 315 kfree(new_name); 316 return -ENXIO; 317 } 318 319 /* 320 * rename and move the name cell. 321 */ 322 list_del(&hc->name_list); 323 old_name = hc->name; 324 hc->name = new_name; 325 list_add(&hc->name_list, _name_buckets + hash_str(new_name)); 326 327 /* 328 * Wake up any dm event waiters. 329 */ 330 table = dm_get_table(hc->md); 331 if (table) { 332 dm_table_event(table); 333 dm_table_put(table); 334 } 335 336 dm_kobject_uevent(hc->md); 337 338 dm_put(hc->md); 339 up_write(&_hash_lock); 340 kfree(old_name); 341 return 0; 342 } 343 344 /*----------------------------------------------------------------- 345 * Implementation of the ioctl commands 346 *---------------------------------------------------------------*/ 347 /* 348 * All the ioctl commands get dispatched to functions with this 349 * prototype. 350 */ 351 typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size); 352 353 static int remove_all(struct dm_ioctl *param, size_t param_size) 354 { 355 dm_hash_remove_all(1); 356 param->data_size = 0; 357 return 0; 358 } 359 360 /* 361 * Round up the ptr to an 8-byte boundary. 362 */ 363 #define ALIGN_MASK 7 364 static inline void *align_ptr(void *ptr) 365 { 366 return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK); 367 } 368 369 /* 370 * Retrieves the data payload buffer from an already allocated 371 * struct dm_ioctl. 372 */ 373 static void *get_result_buffer(struct dm_ioctl *param, size_t param_size, 374 size_t *len) 375 { 376 param->data_start = align_ptr(param + 1) - (void *) param; 377 378 if (param->data_start < param_size) 379 *len = param_size - param->data_start; 380 else 381 *len = 0; 382 383 return ((void *) param) + param->data_start; 384 } 385 386 static int list_devices(struct dm_ioctl *param, size_t param_size) 387 { 388 unsigned int i; 389 struct hash_cell *hc; 390 size_t len, needed = 0; 391 struct gendisk *disk; 392 struct dm_name_list *nl, *old_nl = NULL; 393 394 down_write(&_hash_lock); 395 396 /* 397 * Loop through all the devices working out how much 398 * space we need. 399 */ 400 for (i = 0; i < NUM_BUCKETS; i++) { 401 list_for_each_entry (hc, _name_buckets + i, name_list) { 402 needed += sizeof(struct dm_name_list); 403 needed += strlen(hc->name) + 1; 404 needed += ALIGN_MASK; 405 } 406 } 407 408 /* 409 * Grab our output buffer. 410 */ 411 nl = get_result_buffer(param, param_size, &len); 412 if (len < needed) { 413 param->flags |= DM_BUFFER_FULL_FLAG; 414 goto out; 415 } 416 param->data_size = param->data_start + needed; 417 418 nl->dev = 0; /* Flags no data */ 419 420 /* 421 * Now loop through filling out the names. 422 */ 423 for (i = 0; i < NUM_BUCKETS; i++) { 424 list_for_each_entry (hc, _name_buckets + i, name_list) { 425 if (old_nl) 426 old_nl->next = (uint32_t) ((void *) nl - 427 (void *) old_nl); 428 disk = dm_disk(hc->md); 429 nl->dev = huge_encode_dev(disk_devt(disk)); 430 nl->next = 0; 431 strcpy(nl->name, hc->name); 432 433 old_nl = nl; 434 nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1); 435 } 436 } 437 438 out: 439 up_write(&_hash_lock); 440 return 0; 441 } 442 443 static void list_version_get_needed(struct target_type *tt, void *needed_param) 444 { 445 size_t *needed = needed_param; 446 447 *needed += sizeof(struct dm_target_versions); 448 *needed += strlen(tt->name); 449 *needed += ALIGN_MASK; 450 } 451 452 static void list_version_get_info(struct target_type *tt, void *param) 453 { 454 struct vers_iter *info = param; 455 456 /* Check space - it might have changed since the first iteration */ 457 if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 > 458 info->end) { 459 460 info->flags = DM_BUFFER_FULL_FLAG; 461 return; 462 } 463 464 if (info->old_vers) 465 info->old_vers->next = (uint32_t) ((void *)info->vers - 466 (void *)info->old_vers); 467 info->vers->version[0] = tt->version[0]; 468 info->vers->version[1] = tt->version[1]; 469 info->vers->version[2] = tt->version[2]; 470 info->vers->next = 0; 471 strcpy(info->vers->name, tt->name); 472 473 info->old_vers = info->vers; 474 info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1); 475 } 476 477 static int list_versions(struct dm_ioctl *param, size_t param_size) 478 { 479 size_t len, needed = 0; 480 struct dm_target_versions *vers; 481 struct vers_iter iter_info; 482 483 /* 484 * Loop through all the devices working out how much 485 * space we need. 486 */ 487 dm_target_iterate(list_version_get_needed, &needed); 488 489 /* 490 * Grab our output buffer. 491 */ 492 vers = get_result_buffer(param, param_size, &len); 493 if (len < needed) { 494 param->flags |= DM_BUFFER_FULL_FLAG; 495 goto out; 496 } 497 param->data_size = param->data_start + needed; 498 499 iter_info.param_size = param_size; 500 iter_info.old_vers = NULL; 501 iter_info.vers = vers; 502 iter_info.flags = 0; 503 iter_info.end = (char *)vers+len; 504 505 /* 506 * Now loop through filling out the names & versions. 507 */ 508 dm_target_iterate(list_version_get_info, &iter_info); 509 param->flags |= iter_info.flags; 510 511 out: 512 return 0; 513 } 514 515 516 517 static int check_name(const char *name) 518 { 519 if (strchr(name, '/')) { 520 DMWARN("invalid device name"); 521 return -EINVAL; 522 } 523 524 return 0; 525 } 526 527 /* 528 * Fills in a dm_ioctl structure, ready for sending back to 529 * userland. 530 */ 531 static int __dev_status(struct mapped_device *md, struct dm_ioctl *param) 532 { 533 struct gendisk *disk = dm_disk(md); 534 struct dm_table *table; 535 536 param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG | 537 DM_ACTIVE_PRESENT_FLAG); 538 539 if (dm_suspended(md)) 540 param->flags |= DM_SUSPEND_FLAG; 541 542 param->dev = huge_encode_dev(disk_devt(disk)); 543 544 /* 545 * Yes, this will be out of date by the time it gets back 546 * to userland, but it is still very useful for 547 * debugging. 548 */ 549 param->open_count = dm_open_count(md); 550 551 if (get_disk_ro(disk)) 552 param->flags |= DM_READONLY_FLAG; 553 554 param->event_nr = dm_get_event_nr(md); 555 556 table = dm_get_table(md); 557 if (table) { 558 param->flags |= DM_ACTIVE_PRESENT_FLAG; 559 param->target_count = dm_table_get_num_targets(table); 560 dm_table_put(table); 561 } else 562 param->target_count = 0; 563 564 return 0; 565 } 566 567 static int dev_create(struct dm_ioctl *param, size_t param_size) 568 { 569 int r, m = DM_ANY_MINOR; 570 struct mapped_device *md; 571 572 r = check_name(param->name); 573 if (r) 574 return r; 575 576 if (param->flags & DM_PERSISTENT_DEV_FLAG) 577 m = MINOR(huge_decode_dev(param->dev)); 578 579 r = dm_create(m, &md); 580 if (r) 581 return r; 582 583 r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md); 584 if (r) { 585 dm_put(md); 586 return r; 587 } 588 589 param->flags &= ~DM_INACTIVE_PRESENT_FLAG; 590 591 r = __dev_status(md, param); 592 dm_put(md); 593 594 return r; 595 } 596 597 /* 598 * Always use UUID for lookups if it's present, otherwise use name or dev. 599 */ 600 static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param) 601 { 602 struct mapped_device *md; 603 void *mdptr = NULL; 604 605 if (*param->uuid) 606 return __get_uuid_cell(param->uuid); 607 608 if (*param->name) 609 return __get_name_cell(param->name); 610 611 md = dm_get_md(huge_decode_dev(param->dev)); 612 if (!md) 613 goto out; 614 615 mdptr = dm_get_mdptr(md); 616 if (!mdptr) 617 dm_put(md); 618 619 out: 620 return mdptr; 621 } 622 623 static struct mapped_device *find_device(struct dm_ioctl *param) 624 { 625 struct hash_cell *hc; 626 struct mapped_device *md = NULL; 627 628 down_read(&_hash_lock); 629 hc = __find_device_hash_cell(param); 630 if (hc) { 631 md = hc->md; 632 633 /* 634 * Sneakily write in both the name and the uuid 635 * while we have the cell. 636 */ 637 strncpy(param->name, hc->name, sizeof(param->name)); 638 if (hc->uuid) 639 strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1); 640 else 641 param->uuid[0] = '\0'; 642 643 if (hc->new_map) 644 param->flags |= DM_INACTIVE_PRESENT_FLAG; 645 else 646 param->flags &= ~DM_INACTIVE_PRESENT_FLAG; 647 } 648 up_read(&_hash_lock); 649 650 return md; 651 } 652 653 static int dev_remove(struct dm_ioctl *param, size_t param_size) 654 { 655 struct hash_cell *hc; 656 struct mapped_device *md; 657 int r; 658 659 down_write(&_hash_lock); 660 hc = __find_device_hash_cell(param); 661 662 if (!hc) { 663 DMWARN("device doesn't appear to be in the dev hash table."); 664 up_write(&_hash_lock); 665 return -ENXIO; 666 } 667 668 md = hc->md; 669 670 /* 671 * Ensure the device is not open and nothing further can open it. 672 */ 673 r = dm_lock_for_deletion(md); 674 if (r) { 675 DMWARN("unable to remove open device %s", hc->name); 676 up_write(&_hash_lock); 677 dm_put(md); 678 return r; 679 } 680 681 __hash_remove(hc); 682 up_write(&_hash_lock); 683 dm_put(md); 684 param->data_size = 0; 685 return 0; 686 } 687 688 /* 689 * Check a string doesn't overrun the chunk of 690 * memory we copied from userland. 691 */ 692 static int invalid_str(char *str, void *end) 693 { 694 while ((void *) str < end) 695 if (!*str++) 696 return 0; 697 698 return -EINVAL; 699 } 700 701 static int dev_rename(struct dm_ioctl *param, size_t param_size) 702 { 703 int r; 704 char *new_name = (char *) param + param->data_start; 705 706 if (new_name < param->data || 707 invalid_str(new_name, (void *) param + param_size)) { 708 DMWARN("Invalid new logical volume name supplied."); 709 return -EINVAL; 710 } 711 712 r = check_name(new_name); 713 if (r) 714 return r; 715 716 param->data_size = 0; 717 return dm_hash_rename(param->name, new_name); 718 } 719 720 static int dev_set_geometry(struct dm_ioctl *param, size_t param_size) 721 { 722 int r = -EINVAL, x; 723 struct mapped_device *md; 724 struct hd_geometry geometry; 725 unsigned long indata[4]; 726 char *geostr = (char *) param + param->data_start; 727 728 md = find_device(param); 729 if (!md) 730 return -ENXIO; 731 732 if (geostr < param->data || 733 invalid_str(geostr, (void *) param + param_size)) { 734 DMWARN("Invalid geometry supplied."); 735 goto out; 736 } 737 738 x = sscanf(geostr, "%lu %lu %lu %lu", indata, 739 indata + 1, indata + 2, indata + 3); 740 741 if (x != 4) { 742 DMWARN("Unable to interpret geometry settings."); 743 goto out; 744 } 745 746 if (indata[0] > 65535 || indata[1] > 255 || 747 indata[2] > 255 || indata[3] > ULONG_MAX) { 748 DMWARN("Geometry exceeds range limits."); 749 goto out; 750 } 751 752 geometry.cylinders = indata[0]; 753 geometry.heads = indata[1]; 754 geometry.sectors = indata[2]; 755 geometry.start = indata[3]; 756 757 r = dm_set_geometry(md, &geometry); 758 if (!r) 759 r = __dev_status(md, param); 760 761 param->data_size = 0; 762 763 out: 764 dm_put(md); 765 return r; 766 } 767 768 static int do_suspend(struct dm_ioctl *param) 769 { 770 int r = 0; 771 unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG; 772 struct mapped_device *md; 773 774 md = find_device(param); 775 if (!md) 776 return -ENXIO; 777 778 if (param->flags & DM_SKIP_LOCKFS_FLAG) 779 suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG; 780 if (param->flags & DM_NOFLUSH_FLAG) 781 suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG; 782 783 if (!dm_suspended(md)) 784 r = dm_suspend(md, suspend_flags); 785 786 if (!r) 787 r = __dev_status(md, param); 788 789 dm_put(md); 790 return r; 791 } 792 793 static int do_resume(struct dm_ioctl *param) 794 { 795 int r = 0; 796 unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG; 797 struct hash_cell *hc; 798 struct mapped_device *md; 799 struct dm_table *new_map; 800 801 down_write(&_hash_lock); 802 803 hc = __find_device_hash_cell(param); 804 if (!hc) { 805 DMWARN("device doesn't appear to be in the dev hash table."); 806 up_write(&_hash_lock); 807 return -ENXIO; 808 } 809 810 md = hc->md; 811 812 new_map = hc->new_map; 813 hc->new_map = NULL; 814 param->flags &= ~DM_INACTIVE_PRESENT_FLAG; 815 816 up_write(&_hash_lock); 817 818 /* Do we need to load a new map ? */ 819 if (new_map) { 820 /* Suspend if it isn't already suspended */ 821 if (param->flags & DM_SKIP_LOCKFS_FLAG) 822 suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG; 823 if (param->flags & DM_NOFLUSH_FLAG) 824 suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG; 825 if (!dm_suspended(md)) 826 dm_suspend(md, suspend_flags); 827 828 r = dm_swap_table(md, new_map); 829 if (r) { 830 dm_put(md); 831 dm_table_put(new_map); 832 return r; 833 } 834 835 if (dm_table_get_mode(new_map) & FMODE_WRITE) 836 set_disk_ro(dm_disk(md), 0); 837 else 838 set_disk_ro(dm_disk(md), 1); 839 840 dm_table_put(new_map); 841 } 842 843 if (dm_suspended(md)) 844 r = dm_resume(md); 845 846 if (!r) 847 r = __dev_status(md, param); 848 849 dm_put(md); 850 return r; 851 } 852 853 /* 854 * Set or unset the suspension state of a device. 855 * If the device already is in the requested state we just return its status. 856 */ 857 static int dev_suspend(struct dm_ioctl *param, size_t param_size) 858 { 859 if (param->flags & DM_SUSPEND_FLAG) 860 return do_suspend(param); 861 862 return do_resume(param); 863 } 864 865 /* 866 * Copies device info back to user space, used by 867 * the create and info ioctls. 868 */ 869 static int dev_status(struct dm_ioctl *param, size_t param_size) 870 { 871 int r; 872 struct mapped_device *md; 873 874 md = find_device(param); 875 if (!md) 876 return -ENXIO; 877 878 r = __dev_status(md, param); 879 dm_put(md); 880 return r; 881 } 882 883 /* 884 * Build up the status struct for each target 885 */ 886 static void retrieve_status(struct dm_table *table, 887 struct dm_ioctl *param, size_t param_size) 888 { 889 unsigned int i, num_targets; 890 struct dm_target_spec *spec; 891 char *outbuf, *outptr; 892 status_type_t type; 893 size_t remaining, len, used = 0; 894 895 outptr = outbuf = get_result_buffer(param, param_size, &len); 896 897 if (param->flags & DM_STATUS_TABLE_FLAG) 898 type = STATUSTYPE_TABLE; 899 else 900 type = STATUSTYPE_INFO; 901 902 /* Get all the target info */ 903 num_targets = dm_table_get_num_targets(table); 904 for (i = 0; i < num_targets; i++) { 905 struct dm_target *ti = dm_table_get_target(table, i); 906 907 remaining = len - (outptr - outbuf); 908 if (remaining <= sizeof(struct dm_target_spec)) { 909 param->flags |= DM_BUFFER_FULL_FLAG; 910 break; 911 } 912 913 spec = (struct dm_target_spec *) outptr; 914 915 spec->status = 0; 916 spec->sector_start = ti->begin; 917 spec->length = ti->len; 918 strncpy(spec->target_type, ti->type->name, 919 sizeof(spec->target_type)); 920 921 outptr += sizeof(struct dm_target_spec); 922 remaining = len - (outptr - outbuf); 923 if (remaining <= 0) { 924 param->flags |= DM_BUFFER_FULL_FLAG; 925 break; 926 } 927 928 /* Get the status/table string from the target driver */ 929 if (ti->type->status) { 930 if (ti->type->status(ti, type, outptr, remaining)) { 931 param->flags |= DM_BUFFER_FULL_FLAG; 932 break; 933 } 934 } else 935 outptr[0] = '\0'; 936 937 outptr += strlen(outptr) + 1; 938 used = param->data_start + (outptr - outbuf); 939 940 outptr = align_ptr(outptr); 941 spec->next = outptr - outbuf; 942 } 943 944 if (used) 945 param->data_size = used; 946 947 param->target_count = num_targets; 948 } 949 950 /* 951 * Wait for a device to report an event 952 */ 953 static int dev_wait(struct dm_ioctl *param, size_t param_size) 954 { 955 int r; 956 struct mapped_device *md; 957 struct dm_table *table; 958 959 md = find_device(param); 960 if (!md) 961 return -ENXIO; 962 963 /* 964 * Wait for a notification event 965 */ 966 if (dm_wait_event(md, param->event_nr)) { 967 r = -ERESTARTSYS; 968 goto out; 969 } 970 971 /* 972 * The userland program is going to want to know what 973 * changed to trigger the event, so we may as well tell 974 * him and save an ioctl. 975 */ 976 r = __dev_status(md, param); 977 if (r) 978 goto out; 979 980 table = dm_get_table(md); 981 if (table) { 982 retrieve_status(table, param, param_size); 983 dm_table_put(table); 984 } 985 986 out: 987 dm_put(md); 988 return r; 989 } 990 991 static inline int get_mode(struct dm_ioctl *param) 992 { 993 int mode = FMODE_READ | FMODE_WRITE; 994 995 if (param->flags & DM_READONLY_FLAG) 996 mode = FMODE_READ; 997 998 return mode; 999 } 1000 1001 static int next_target(struct dm_target_spec *last, uint32_t next, void *end, 1002 struct dm_target_spec **spec, char **target_params) 1003 { 1004 *spec = (struct dm_target_spec *) ((unsigned char *) last + next); 1005 *target_params = (char *) (*spec + 1); 1006 1007 if (*spec < (last + 1)) 1008 return -EINVAL; 1009 1010 return invalid_str(*target_params, end); 1011 } 1012 1013 static int populate_table(struct dm_table *table, 1014 struct dm_ioctl *param, size_t param_size) 1015 { 1016 int r; 1017 unsigned int i = 0; 1018 struct dm_target_spec *spec = (struct dm_target_spec *) param; 1019 uint32_t next = param->data_start; 1020 void *end = (void *) param + param_size; 1021 char *target_params; 1022 1023 if (!param->target_count) { 1024 DMWARN("populate_table: no targets specified"); 1025 return -EINVAL; 1026 } 1027 1028 for (i = 0; i < param->target_count; i++) { 1029 1030 r = next_target(spec, next, end, &spec, &target_params); 1031 if (r) { 1032 DMWARN("unable to find target"); 1033 return r; 1034 } 1035 1036 r = dm_table_add_target(table, spec->target_type, 1037 (sector_t) spec->sector_start, 1038 (sector_t) spec->length, 1039 target_params); 1040 if (r) { 1041 DMWARN("error adding target to table"); 1042 return r; 1043 } 1044 1045 next = spec->next; 1046 } 1047 1048 return dm_table_complete(table); 1049 } 1050 1051 static int table_load(struct dm_ioctl *param, size_t param_size) 1052 { 1053 int r; 1054 struct hash_cell *hc; 1055 struct dm_table *t; 1056 struct mapped_device *md; 1057 1058 md = find_device(param); 1059 if (!md) 1060 return -ENXIO; 1061 1062 r = dm_table_create(&t, get_mode(param), param->target_count, md); 1063 if (r) 1064 goto out; 1065 1066 r = populate_table(t, param, param_size); 1067 if (r) { 1068 dm_table_put(t); 1069 goto out; 1070 } 1071 1072 down_write(&_hash_lock); 1073 hc = dm_get_mdptr(md); 1074 if (!hc || hc->md != md) { 1075 DMWARN("device has been removed from the dev hash table."); 1076 dm_table_put(t); 1077 up_write(&_hash_lock); 1078 r = -ENXIO; 1079 goto out; 1080 } 1081 1082 if (hc->new_map) 1083 dm_table_put(hc->new_map); 1084 hc->new_map = t; 1085 up_write(&_hash_lock); 1086 1087 param->flags |= DM_INACTIVE_PRESENT_FLAG; 1088 r = __dev_status(md, param); 1089 1090 out: 1091 dm_put(md); 1092 1093 return r; 1094 } 1095 1096 static int table_clear(struct dm_ioctl *param, size_t param_size) 1097 { 1098 int r; 1099 struct hash_cell *hc; 1100 struct mapped_device *md; 1101 1102 down_write(&_hash_lock); 1103 1104 hc = __find_device_hash_cell(param); 1105 if (!hc) { 1106 DMWARN("device doesn't appear to be in the dev hash table."); 1107 up_write(&_hash_lock); 1108 return -ENXIO; 1109 } 1110 1111 if (hc->new_map) { 1112 dm_table_put(hc->new_map); 1113 hc->new_map = NULL; 1114 } 1115 1116 param->flags &= ~DM_INACTIVE_PRESENT_FLAG; 1117 1118 r = __dev_status(hc->md, param); 1119 md = hc->md; 1120 up_write(&_hash_lock); 1121 dm_put(md); 1122 return r; 1123 } 1124 1125 /* 1126 * Retrieves a list of devices used by a particular dm device. 1127 */ 1128 static void retrieve_deps(struct dm_table *table, 1129 struct dm_ioctl *param, size_t param_size) 1130 { 1131 unsigned int count = 0; 1132 struct list_head *tmp; 1133 size_t len, needed; 1134 struct dm_dev_internal *dd; 1135 struct dm_target_deps *deps; 1136 1137 deps = get_result_buffer(param, param_size, &len); 1138 1139 /* 1140 * Count the devices. 1141 */ 1142 list_for_each (tmp, dm_table_get_devices(table)) 1143 count++; 1144 1145 /* 1146 * Check we have enough space. 1147 */ 1148 needed = sizeof(*deps) + (sizeof(*deps->dev) * count); 1149 if (len < needed) { 1150 param->flags |= DM_BUFFER_FULL_FLAG; 1151 return; 1152 } 1153 1154 /* 1155 * Fill in the devices. 1156 */ 1157 deps->count = count; 1158 count = 0; 1159 list_for_each_entry (dd, dm_table_get_devices(table), list) 1160 deps->dev[count++] = huge_encode_dev(dd->dm_dev.bdev->bd_dev); 1161 1162 param->data_size = param->data_start + needed; 1163 } 1164 1165 static int table_deps(struct dm_ioctl *param, size_t param_size) 1166 { 1167 int r = 0; 1168 struct mapped_device *md; 1169 struct dm_table *table; 1170 1171 md = find_device(param); 1172 if (!md) 1173 return -ENXIO; 1174 1175 r = __dev_status(md, param); 1176 if (r) 1177 goto out; 1178 1179 table = dm_get_table(md); 1180 if (table) { 1181 retrieve_deps(table, param, param_size); 1182 dm_table_put(table); 1183 } 1184 1185 out: 1186 dm_put(md); 1187 return r; 1188 } 1189 1190 /* 1191 * Return the status of a device as a text string for each 1192 * target. 1193 */ 1194 static int table_status(struct dm_ioctl *param, size_t param_size) 1195 { 1196 int r; 1197 struct mapped_device *md; 1198 struct dm_table *table; 1199 1200 md = find_device(param); 1201 if (!md) 1202 return -ENXIO; 1203 1204 r = __dev_status(md, param); 1205 if (r) 1206 goto out; 1207 1208 table = dm_get_table(md); 1209 if (table) { 1210 retrieve_status(table, param, param_size); 1211 dm_table_put(table); 1212 } 1213 1214 out: 1215 dm_put(md); 1216 return r; 1217 } 1218 1219 /* 1220 * Pass a message to the target that's at the supplied device offset. 1221 */ 1222 static int target_message(struct dm_ioctl *param, size_t param_size) 1223 { 1224 int r, argc; 1225 char **argv; 1226 struct mapped_device *md; 1227 struct dm_table *table; 1228 struct dm_target *ti; 1229 struct dm_target_msg *tmsg = (void *) param + param->data_start; 1230 1231 md = find_device(param); 1232 if (!md) 1233 return -ENXIO; 1234 1235 r = __dev_status(md, param); 1236 if (r) 1237 goto out; 1238 1239 if (tmsg < (struct dm_target_msg *) param->data || 1240 invalid_str(tmsg->message, (void *) param + param_size)) { 1241 DMWARN("Invalid target message parameters."); 1242 r = -EINVAL; 1243 goto out; 1244 } 1245 1246 r = dm_split_args(&argc, &argv, tmsg->message); 1247 if (r) { 1248 DMWARN("Failed to split target message parameters"); 1249 goto out; 1250 } 1251 1252 table = dm_get_table(md); 1253 if (!table) 1254 goto out_argv; 1255 1256 ti = dm_table_find_target(table, tmsg->sector); 1257 if (!dm_target_is_valid(ti)) { 1258 DMWARN("Target message sector outside device."); 1259 r = -EINVAL; 1260 } else if (ti->type->message) 1261 r = ti->type->message(ti, argc, argv); 1262 else { 1263 DMWARN("Target type does not support messages"); 1264 r = -EINVAL; 1265 } 1266 1267 dm_table_put(table); 1268 out_argv: 1269 kfree(argv); 1270 out: 1271 param->data_size = 0; 1272 dm_put(md); 1273 return r; 1274 } 1275 1276 /*----------------------------------------------------------------- 1277 * Implementation of open/close/ioctl on the special char 1278 * device. 1279 *---------------------------------------------------------------*/ 1280 static ioctl_fn lookup_ioctl(unsigned int cmd) 1281 { 1282 static struct { 1283 int cmd; 1284 ioctl_fn fn; 1285 } _ioctls[] = { 1286 {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */ 1287 {DM_REMOVE_ALL_CMD, remove_all}, 1288 {DM_LIST_DEVICES_CMD, list_devices}, 1289 1290 {DM_DEV_CREATE_CMD, dev_create}, 1291 {DM_DEV_REMOVE_CMD, dev_remove}, 1292 {DM_DEV_RENAME_CMD, dev_rename}, 1293 {DM_DEV_SUSPEND_CMD, dev_suspend}, 1294 {DM_DEV_STATUS_CMD, dev_status}, 1295 {DM_DEV_WAIT_CMD, dev_wait}, 1296 1297 {DM_TABLE_LOAD_CMD, table_load}, 1298 {DM_TABLE_CLEAR_CMD, table_clear}, 1299 {DM_TABLE_DEPS_CMD, table_deps}, 1300 {DM_TABLE_STATUS_CMD, table_status}, 1301 1302 {DM_LIST_VERSIONS_CMD, list_versions}, 1303 1304 {DM_TARGET_MSG_CMD, target_message}, 1305 {DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry} 1306 }; 1307 1308 return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn; 1309 } 1310 1311 /* 1312 * As well as checking the version compatibility this always 1313 * copies the kernel interface version out. 1314 */ 1315 static int check_version(unsigned int cmd, struct dm_ioctl __user *user) 1316 { 1317 uint32_t version[3]; 1318 int r = 0; 1319 1320 if (copy_from_user(version, user->version, sizeof(version))) 1321 return -EFAULT; 1322 1323 if ((DM_VERSION_MAJOR != version[0]) || 1324 (DM_VERSION_MINOR < version[1])) { 1325 DMWARN("ioctl interface mismatch: " 1326 "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)", 1327 DM_VERSION_MAJOR, DM_VERSION_MINOR, 1328 DM_VERSION_PATCHLEVEL, 1329 version[0], version[1], version[2], cmd); 1330 r = -EINVAL; 1331 } 1332 1333 /* 1334 * Fill in the kernel version. 1335 */ 1336 version[0] = DM_VERSION_MAJOR; 1337 version[1] = DM_VERSION_MINOR; 1338 version[2] = DM_VERSION_PATCHLEVEL; 1339 if (copy_to_user(user->version, version, sizeof(version))) 1340 return -EFAULT; 1341 1342 return r; 1343 } 1344 1345 static void free_params(struct dm_ioctl *param) 1346 { 1347 vfree(param); 1348 } 1349 1350 static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param) 1351 { 1352 struct dm_ioctl tmp, *dmi; 1353 1354 if (copy_from_user(&tmp, user, sizeof(tmp) - sizeof(tmp.data))) 1355 return -EFAULT; 1356 1357 if (tmp.data_size < (sizeof(tmp) - sizeof(tmp.data))) 1358 return -EINVAL; 1359 1360 dmi = vmalloc(tmp.data_size); 1361 if (!dmi) 1362 return -ENOMEM; 1363 1364 if (copy_from_user(dmi, user, tmp.data_size)) { 1365 vfree(dmi); 1366 return -EFAULT; 1367 } 1368 1369 *param = dmi; 1370 return 0; 1371 } 1372 1373 static int validate_params(uint cmd, struct dm_ioctl *param) 1374 { 1375 /* Always clear this flag */ 1376 param->flags &= ~DM_BUFFER_FULL_FLAG; 1377 1378 /* Ignores parameters */ 1379 if (cmd == DM_REMOVE_ALL_CMD || 1380 cmd == DM_LIST_DEVICES_CMD || 1381 cmd == DM_LIST_VERSIONS_CMD) 1382 return 0; 1383 1384 if ((cmd == DM_DEV_CREATE_CMD)) { 1385 if (!*param->name) { 1386 DMWARN("name not supplied when creating device"); 1387 return -EINVAL; 1388 } 1389 } else if ((*param->uuid && *param->name)) { 1390 DMWARN("only supply one of name or uuid, cmd(%u)", cmd); 1391 return -EINVAL; 1392 } 1393 1394 /* Ensure strings are terminated */ 1395 param->name[DM_NAME_LEN - 1] = '\0'; 1396 param->uuid[DM_UUID_LEN - 1] = '\0'; 1397 1398 return 0; 1399 } 1400 1401 static int ctl_ioctl(uint command, struct dm_ioctl __user *user) 1402 { 1403 int r = 0; 1404 unsigned int cmd; 1405 struct dm_ioctl *uninitialized_var(param); 1406 ioctl_fn fn = NULL; 1407 size_t param_size; 1408 1409 /* only root can play with this */ 1410 if (!capable(CAP_SYS_ADMIN)) 1411 return -EACCES; 1412 1413 if (_IOC_TYPE(command) != DM_IOCTL) 1414 return -ENOTTY; 1415 1416 cmd = _IOC_NR(command); 1417 1418 /* 1419 * Check the interface version passed in. This also 1420 * writes out the kernel's interface version. 1421 */ 1422 r = check_version(cmd, user); 1423 if (r) 1424 return r; 1425 1426 /* 1427 * Nothing more to do for the version command. 1428 */ 1429 if (cmd == DM_VERSION_CMD) 1430 return 0; 1431 1432 fn = lookup_ioctl(cmd); 1433 if (!fn) { 1434 DMWARN("dm_ctl_ioctl: unknown command 0x%x", command); 1435 return -ENOTTY; 1436 } 1437 1438 /* 1439 * Trying to avoid low memory issues when a device is 1440 * suspended. 1441 */ 1442 current->flags |= PF_MEMALLOC; 1443 1444 /* 1445 * Copy the parameters into kernel space. 1446 */ 1447 r = copy_params(user, ¶m); 1448 1449 current->flags &= ~PF_MEMALLOC; 1450 1451 if (r) 1452 return r; 1453 1454 r = validate_params(cmd, param); 1455 if (r) 1456 goto out; 1457 1458 param_size = param->data_size; 1459 param->data_size = sizeof(*param); 1460 r = fn(param, param_size); 1461 1462 /* 1463 * Copy the results back to userland. 1464 */ 1465 if (!r && copy_to_user(user, param, param->data_size)) 1466 r = -EFAULT; 1467 1468 out: 1469 free_params(param); 1470 return r; 1471 } 1472 1473 static long dm_ctl_ioctl(struct file *file, uint command, ulong u) 1474 { 1475 return (long)ctl_ioctl(command, (struct dm_ioctl __user *)u); 1476 } 1477 1478 #ifdef CONFIG_COMPAT 1479 static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u) 1480 { 1481 return (long)dm_ctl_ioctl(file, command, (ulong) compat_ptr(u)); 1482 } 1483 #else 1484 #define dm_compat_ctl_ioctl NULL 1485 #endif 1486 1487 static const struct file_operations _ctl_fops = { 1488 .unlocked_ioctl = dm_ctl_ioctl, 1489 .compat_ioctl = dm_compat_ctl_ioctl, 1490 .owner = THIS_MODULE, 1491 }; 1492 1493 static struct miscdevice _dm_misc = { 1494 .minor = MISC_DYNAMIC_MINOR, 1495 .name = DM_NAME, 1496 .fops = &_ctl_fops 1497 }; 1498 1499 /* 1500 * Create misc character device and link to DM_DIR/control. 1501 */ 1502 int __init dm_interface_init(void) 1503 { 1504 int r; 1505 1506 r = dm_hash_init(); 1507 if (r) 1508 return r; 1509 1510 r = misc_register(&_dm_misc); 1511 if (r) { 1512 DMERR("misc_register failed for control device"); 1513 dm_hash_exit(); 1514 return r; 1515 } 1516 1517 DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR, 1518 DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA, 1519 DM_DRIVER_EMAIL); 1520 return 0; 1521 } 1522 1523 void dm_interface_exit(void) 1524 { 1525 if (misc_deregister(&_dm_misc) < 0) 1526 DMERR("misc_deregister failed for control device"); 1527 1528 dm_hash_exit(); 1529 } 1530 1531 /** 1532 * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers 1533 * @md: Pointer to mapped_device 1534 * @name: Buffer (size DM_NAME_LEN) for name 1535 * @uuid: Buffer (size DM_UUID_LEN) for uuid or empty string if uuid not defined 1536 */ 1537 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid) 1538 { 1539 int r = 0; 1540 struct hash_cell *hc; 1541 1542 if (!md) 1543 return -ENXIO; 1544 1545 dm_get(md); 1546 down_read(&_hash_lock); 1547 hc = dm_get_mdptr(md); 1548 if (!hc || hc->md != md) { 1549 r = -ENXIO; 1550 goto out; 1551 } 1552 1553 strcpy(name, hc->name); 1554 strcpy(uuid, hc->uuid ? : ""); 1555 1556 out: 1557 up_read(&_hash_lock); 1558 dm_put(md); 1559 1560 return r; 1561 } 1562