linux/drivers/md/dm-ioctl.c
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   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 *---------------------------------------------------------------*/
  29struct 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
  39struct 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)
  49static struct list_head _name_buckets[NUM_BUCKETS];
  50static struct list_head _uuid_buckets[NUM_BUCKETS];
  51
  52static void dm_hash_remove_all(int keep_open_devices);
  53
  54/*
  55 * Guards access to both hash tables.
  56 */
  57static DECLARE_RWSEM(_hash_lock);
  58
  59/*
  60 * Protects use of mdptr to obtain hash cell name and uuid from mapped device.
  61 */
  62static DEFINE_MUTEX(dm_hash_cells_mutex);
  63
  64static void init_buckets(struct list_head *buckets)
  65{
  66        unsigned int i;
  67
  68        for (i = 0; i < NUM_BUCKETS; i++)
  69                INIT_LIST_HEAD(buckets + i);
  70}
  71
  72static int dm_hash_init(void)
  73{
  74        init_buckets(_name_buckets);
  75        init_buckets(_uuid_buckets);
  76        return 0;
  77}
  78
  79static void dm_hash_exit(void)
  80{
  81        dm_hash_remove_all(0);
  82}
  83
  84/*-----------------------------------------------------------------
  85 * Hash function:
  86 * We're not really concerned with the str hash function being
  87 * fast since it's only used by the ioctl interface.
  88 *---------------------------------------------------------------*/
  89static unsigned int hash_str(const char *str)
  90{
  91        const unsigned int hash_mult = 2654435387U;
  92        unsigned int h = 0;
  93
  94        while (*str)
  95                h = (h + (unsigned int) *str++) * hash_mult;
  96
  97        return h & MASK_BUCKETS;
  98}
  99
 100/*-----------------------------------------------------------------
 101 * Code for looking up a device by name
 102 *---------------------------------------------------------------*/
 103static struct hash_cell *__get_name_cell(const char *str)
 104{
 105        struct hash_cell *hc;
 106        unsigned int h = hash_str(str);
 107
 108        list_for_each_entry (hc, _name_buckets + h, name_list)
 109                if (!strcmp(hc->name, str)) {
 110                        dm_get(hc->md);
 111                        return hc;
 112                }
 113
 114        return NULL;
 115}
 116
 117static struct hash_cell *__get_uuid_cell(const char *str)
 118{
 119        struct hash_cell *hc;
 120        unsigned int h = hash_str(str);
 121
 122        list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
 123                if (!strcmp(hc->uuid, str)) {
 124                        dm_get(hc->md);
 125                        return hc;
 126                }
 127
 128        return NULL;
 129}
 130
 131static struct hash_cell *__get_dev_cell(uint64_t dev)
 132{
 133        struct mapped_device *md;
 134        struct hash_cell *hc;
 135
 136        md = dm_get_md(huge_decode_dev(dev));
 137        if (!md)
 138                return NULL;
 139
 140        hc = dm_get_mdptr(md);
 141        if (!hc) {
 142                dm_put(md);
 143                return NULL;
 144        }
 145
 146        return hc;
 147}
 148
 149/*-----------------------------------------------------------------
 150 * Inserting, removing and renaming a device.
 151 *---------------------------------------------------------------*/
 152static struct hash_cell *alloc_cell(const char *name, const char *uuid,
 153                                    struct mapped_device *md)
 154{
 155        struct hash_cell *hc;
 156
 157        hc = kmalloc(sizeof(*hc), GFP_KERNEL);
 158        if (!hc)
 159                return NULL;
 160
 161        hc->name = kstrdup(name, GFP_KERNEL);
 162        if (!hc->name) {
 163                kfree(hc);
 164                return NULL;
 165        }
 166
 167        if (!uuid)
 168                hc->uuid = NULL;
 169
 170        else {
 171                hc->uuid = kstrdup(uuid, GFP_KERNEL);
 172                if (!hc->uuid) {
 173                        kfree(hc->name);
 174                        kfree(hc);
 175                        return NULL;
 176                }
 177        }
 178
 179        INIT_LIST_HEAD(&hc->name_list);
 180        INIT_LIST_HEAD(&hc->uuid_list);
 181        hc->md = md;
 182        hc->new_map = NULL;
 183        return hc;
 184}
 185
 186static void free_cell(struct hash_cell *hc)
 187{
 188        if (hc) {
 189                kfree(hc->name);
 190                kfree(hc->uuid);
 191                kfree(hc);
 192        }
 193}
 194
 195/*
 196 * The kdev_t and uuid of a device can never change once it is
 197 * initially inserted.
 198 */
 199static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
 200{
 201        struct hash_cell *cell, *hc;
 202
 203        /*
 204         * Allocate the new cells.
 205         */
 206        cell = alloc_cell(name, uuid, md);
 207        if (!cell)
 208                return -ENOMEM;
 209
 210        /*
 211         * Insert the cell into both hash tables.
 212         */
 213        down_write(&_hash_lock);
 214        hc = __get_name_cell(name);
 215        if (hc) {
 216                dm_put(hc->md);
 217                goto bad;
 218        }
 219
 220        list_add(&cell->name_list, _name_buckets + hash_str(name));
 221
 222        if (uuid) {
 223                hc = __get_uuid_cell(uuid);
 224                if (hc) {
 225                        list_del(&cell->name_list);
 226                        dm_put(hc->md);
 227                        goto bad;
 228                }
 229                list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
 230        }
 231        dm_get(md);
 232        mutex_lock(&dm_hash_cells_mutex);
 233        dm_set_mdptr(md, cell);
 234        mutex_unlock(&dm_hash_cells_mutex);
 235        up_write(&_hash_lock);
 236
 237        return 0;
 238
 239 bad:
 240        up_write(&_hash_lock);
 241        free_cell(cell);
 242        return -EBUSY;
 243}
 244
 245static void __hash_remove(struct hash_cell *hc)
 246{
 247        struct dm_table *table;
 248
 249        /* remove from the dev hash */
 250        list_del(&hc->uuid_list);
 251        list_del(&hc->name_list);
 252        mutex_lock(&dm_hash_cells_mutex);
 253        dm_set_mdptr(hc->md, NULL);
 254        mutex_unlock(&dm_hash_cells_mutex);
 255
 256        table = dm_get_live_table(hc->md);
 257        if (table) {
 258                dm_table_event(table);
 259                dm_table_put(table);
 260        }
 261
 262        if (hc->new_map)
 263                dm_table_destroy(hc->new_map);
 264        dm_put(hc->md);
 265        free_cell(hc);
 266}
 267
 268static void dm_hash_remove_all(int keep_open_devices)
 269{
 270        int i, dev_skipped;
 271        struct hash_cell *hc;
 272        struct mapped_device *md;
 273
 274retry:
 275        dev_skipped = 0;
 276
 277        down_write(&_hash_lock);
 278
 279        for (i = 0; i < NUM_BUCKETS; i++) {
 280                list_for_each_entry(hc, _name_buckets + i, name_list) {
 281                        md = hc->md;
 282                        dm_get(md);
 283
 284                        if (keep_open_devices && dm_lock_for_deletion(md)) {
 285                                dm_put(md);
 286                                dev_skipped++;
 287                                continue;
 288                        }
 289
 290                        __hash_remove(hc);
 291
 292                        up_write(&_hash_lock);
 293
 294                        dm_put(md);
 295                        if (likely(keep_open_devices))
 296                                dm_destroy(md);
 297                        else
 298                                dm_destroy_immediate(md);
 299
 300                        /*
 301                         * Some mapped devices may be using other mapped
 302                         * devices, so repeat until we make no further
 303                         * progress.  If a new mapped device is created
 304                         * here it will also get removed.
 305                         */
 306                        goto retry;
 307                }
 308        }
 309
 310        up_write(&_hash_lock);
 311
 312        if (dev_skipped)
 313                DMWARN("remove_all left %d open device(s)", dev_skipped);
 314}
 315
 316/*
 317 * Set the uuid of a hash_cell that isn't already set.
 318 */
 319static void __set_cell_uuid(struct hash_cell *hc, char *new_uuid)
 320{
 321        mutex_lock(&dm_hash_cells_mutex);
 322        hc->uuid = new_uuid;
 323        mutex_unlock(&dm_hash_cells_mutex);
 324
 325        list_add(&hc->uuid_list, _uuid_buckets + hash_str(new_uuid));
 326}
 327
 328/*
 329 * Changes the name of a hash_cell and returns the old name for
 330 * the caller to free.
 331 */
 332static char *__change_cell_name(struct hash_cell *hc, char *new_name)
 333{
 334        char *old_name;
 335
 336        /*
 337         * Rename and move the name cell.
 338         */
 339        list_del(&hc->name_list);
 340        old_name = hc->name;
 341
 342        mutex_lock(&dm_hash_cells_mutex);
 343        hc->name = new_name;
 344        mutex_unlock(&dm_hash_cells_mutex);
 345
 346        list_add(&hc->name_list, _name_buckets + hash_str(new_name));
 347
 348        return old_name;
 349}
 350
 351static struct mapped_device *dm_hash_rename(struct dm_ioctl *param,
 352                                            const char *new)
 353{
 354        char *new_data, *old_name = NULL;
 355        struct hash_cell *hc;
 356        struct dm_table *table;
 357        struct mapped_device *md;
 358        unsigned change_uuid = (param->flags & DM_UUID_FLAG) ? 1 : 0;
 359
 360        /*
 361         * duplicate new.
 362         */
 363        new_data = kstrdup(new, GFP_KERNEL);
 364        if (!new_data)
 365                return ERR_PTR(-ENOMEM);
 366
 367        down_write(&_hash_lock);
 368
 369        /*
 370         * Is new free ?
 371         */
 372        if (change_uuid)
 373                hc = __get_uuid_cell(new);
 374        else
 375                hc = __get_name_cell(new);
 376
 377        if (hc) {
 378                DMWARN("Unable to change %s on mapped device %s to one that "
 379                       "already exists: %s",
 380                       change_uuid ? "uuid" : "name",
 381                       param->name, new);
 382                dm_put(hc->md);
 383                up_write(&_hash_lock);
 384                kfree(new_data);
 385                return ERR_PTR(-EBUSY);
 386        }
 387
 388        /*
 389         * Is there such a device as 'old' ?
 390         */
 391        hc = __get_name_cell(param->name);
 392        if (!hc) {
 393                DMWARN("Unable to rename non-existent device, %s to %s%s",
 394                       param->name, change_uuid ? "uuid " : "", new);
 395                up_write(&_hash_lock);
 396                kfree(new_data);
 397                return ERR_PTR(-ENXIO);
 398        }
 399
 400        /*
 401         * Does this device already have a uuid?
 402         */
 403        if (change_uuid && hc->uuid) {
 404                DMWARN("Unable to change uuid of mapped device %s to %s "
 405                       "because uuid is already set to %s",
 406                       param->name, new, hc->uuid);
 407                dm_put(hc->md);
 408                up_write(&_hash_lock);
 409                kfree(new_data);
 410                return ERR_PTR(-EINVAL);
 411        }
 412
 413        if (change_uuid)
 414                __set_cell_uuid(hc, new_data);
 415        else
 416                old_name = __change_cell_name(hc, new_data);
 417
 418        /*
 419         * Wake up any dm event waiters.
 420         */
 421        table = dm_get_live_table(hc->md);
 422        if (table) {
 423                dm_table_event(table);
 424                dm_table_put(table);
 425        }
 426
 427        if (!dm_kobject_uevent(hc->md, KOBJ_CHANGE, param->event_nr))
 428                param->flags |= DM_UEVENT_GENERATED_FLAG;
 429
 430        md = hc->md;
 431        up_write(&_hash_lock);
 432        kfree(old_name);
 433
 434        return md;
 435}
 436
 437/*-----------------------------------------------------------------
 438 * Implementation of the ioctl commands
 439 *---------------------------------------------------------------*/
 440/*
 441 * All the ioctl commands get dispatched to functions with this
 442 * prototype.
 443 */
 444typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
 445
 446static int remove_all(struct dm_ioctl *param, size_t param_size)
 447{
 448        dm_hash_remove_all(1);
 449        param->data_size = 0;
 450        return 0;
 451}
 452
 453/*
 454 * Round up the ptr to an 8-byte boundary.
 455 */
 456#define ALIGN_MASK 7
 457static inline void *align_ptr(void *ptr)
 458{
 459        return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
 460}
 461
 462/*
 463 * Retrieves the data payload buffer from an already allocated
 464 * struct dm_ioctl.
 465 */
 466static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
 467                               size_t *len)
 468{
 469        param->data_start = align_ptr(param + 1) - (void *) param;
 470
 471        if (param->data_start < param_size)
 472                *len = param_size - param->data_start;
 473        else
 474                *len = 0;
 475
 476        return ((void *) param) + param->data_start;
 477}
 478
 479static int list_devices(struct dm_ioctl *param, size_t param_size)
 480{
 481        unsigned int i;
 482        struct hash_cell *hc;
 483        size_t len, needed = 0;
 484        struct gendisk *disk;
 485        struct dm_name_list *nl, *old_nl = NULL;
 486
 487        down_write(&_hash_lock);
 488
 489        /*
 490         * Loop through all the devices working out how much
 491         * space we need.
 492         */
 493        for (i = 0; i < NUM_BUCKETS; i++) {
 494                list_for_each_entry (hc, _name_buckets + i, name_list) {
 495                        needed += sizeof(struct dm_name_list);
 496                        needed += strlen(hc->name) + 1;
 497                        needed += ALIGN_MASK;
 498                }
 499        }
 500
 501        /*
 502         * Grab our output buffer.
 503         */
 504        nl = get_result_buffer(param, param_size, &len);
 505        if (len < needed) {
 506                param->flags |= DM_BUFFER_FULL_FLAG;
 507                goto out;
 508        }
 509        param->data_size = param->data_start + needed;
 510
 511        nl->dev = 0;    /* Flags no data */
 512
 513        /*
 514         * Now loop through filling out the names.
 515         */
 516        for (i = 0; i < NUM_BUCKETS; i++) {
 517                list_for_each_entry (hc, _name_buckets + i, name_list) {
 518                        if (old_nl)
 519                                old_nl->next = (uint32_t) ((void *) nl -
 520                                                           (void *) old_nl);
 521                        disk = dm_disk(hc->md);
 522                        nl->dev = huge_encode_dev(disk_devt(disk));
 523                        nl->next = 0;
 524                        strcpy(nl->name, hc->name);
 525
 526                        old_nl = nl;
 527                        nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
 528                }
 529        }
 530
 531 out:
 532        up_write(&_hash_lock);
 533        return 0;
 534}
 535
 536static void list_version_get_needed(struct target_type *tt, void *needed_param)
 537{
 538    size_t *needed = needed_param;
 539
 540    *needed += sizeof(struct dm_target_versions);
 541    *needed += strlen(tt->name);
 542    *needed += ALIGN_MASK;
 543}
 544
 545static void list_version_get_info(struct target_type *tt, void *param)
 546{
 547    struct vers_iter *info = param;
 548
 549    /* Check space - it might have changed since the first iteration */
 550    if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
 551        info->end) {
 552
 553        info->flags = DM_BUFFER_FULL_FLAG;
 554        return;
 555    }
 556
 557    if (info->old_vers)
 558        info->old_vers->next = (uint32_t) ((void *)info->vers -
 559                                           (void *)info->old_vers);
 560    info->vers->version[0] = tt->version[0];
 561    info->vers->version[1] = tt->version[1];
 562    info->vers->version[2] = tt->version[2];
 563    info->vers->next = 0;
 564    strcpy(info->vers->name, tt->name);
 565
 566    info->old_vers = info->vers;
 567    info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
 568}
 569
 570static int list_versions(struct dm_ioctl *param, size_t param_size)
 571{
 572        size_t len, needed = 0;
 573        struct dm_target_versions *vers;
 574        struct vers_iter iter_info;
 575
 576        /*
 577         * Loop through all the devices working out how much
 578         * space we need.
 579         */
 580        dm_target_iterate(list_version_get_needed, &needed);
 581
 582        /*
 583         * Grab our output buffer.
 584         */
 585        vers = get_result_buffer(param, param_size, &len);
 586        if (len < needed) {
 587                param->flags |= DM_BUFFER_FULL_FLAG;
 588                goto out;
 589        }
 590        param->data_size = param->data_start + needed;
 591
 592        iter_info.param_size = param_size;
 593        iter_info.old_vers = NULL;
 594        iter_info.vers = vers;
 595        iter_info.flags = 0;
 596        iter_info.end = (char *)vers+len;
 597
 598        /*
 599         * Now loop through filling out the names & versions.
 600         */
 601        dm_target_iterate(list_version_get_info, &iter_info);
 602        param->flags |= iter_info.flags;
 603
 604 out:
 605        return 0;
 606}
 607
 608static int check_name(const char *name)
 609{
 610        if (strchr(name, '/')) {
 611                DMWARN("invalid device name");
 612                return -EINVAL;
 613        }
 614
 615        return 0;
 616}
 617
 618/*
 619 * On successful return, the caller must not attempt to acquire
 620 * _hash_lock without first calling dm_table_put, because dm_table_destroy
 621 * waits for this dm_table_put and could be called under this lock.
 622 */
 623static struct dm_table *dm_get_inactive_table(struct mapped_device *md)
 624{
 625        struct hash_cell *hc;
 626        struct dm_table *table = NULL;
 627
 628        down_read(&_hash_lock);
 629        hc = dm_get_mdptr(md);
 630        if (!hc || hc->md != md) {
 631                DMWARN("device has been removed from the dev hash table.");
 632                goto out;
 633        }
 634
 635        table = hc->new_map;
 636        if (table)
 637                dm_table_get(table);
 638
 639out:
 640        up_read(&_hash_lock);
 641
 642        return table;
 643}
 644
 645static struct dm_table *dm_get_live_or_inactive_table(struct mapped_device *md,
 646                                                      struct dm_ioctl *param)
 647{
 648        return (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) ?
 649                dm_get_inactive_table(md) : dm_get_live_table(md);
 650}
 651
 652/*
 653 * Fills in a dm_ioctl structure, ready for sending back to
 654 * userland.
 655 */
 656static void __dev_status(struct mapped_device *md, struct dm_ioctl *param)
 657{
 658        struct gendisk *disk = dm_disk(md);
 659        struct dm_table *table;
 660
 661        param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
 662                          DM_ACTIVE_PRESENT_FLAG);
 663
 664        if (dm_suspended_md(md))
 665                param->flags |= DM_SUSPEND_FLAG;
 666
 667        param->dev = huge_encode_dev(disk_devt(disk));
 668
 669        /*
 670         * Yes, this will be out of date by the time it gets back
 671         * to userland, but it is still very useful for
 672         * debugging.
 673         */
 674        param->open_count = dm_open_count(md);
 675
 676        param->event_nr = dm_get_event_nr(md);
 677        param->target_count = 0;
 678
 679        table = dm_get_live_table(md);
 680        if (table) {
 681                if (!(param->flags & DM_QUERY_INACTIVE_TABLE_FLAG)) {
 682                        if (get_disk_ro(disk))
 683                                param->flags |= DM_READONLY_FLAG;
 684                        param->target_count = dm_table_get_num_targets(table);
 685                }
 686                dm_table_put(table);
 687
 688                param->flags |= DM_ACTIVE_PRESENT_FLAG;
 689        }
 690
 691        if (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) {
 692                table = dm_get_inactive_table(md);
 693                if (table) {
 694                        if (!(dm_table_get_mode(table) & FMODE_WRITE))
 695                                param->flags |= DM_READONLY_FLAG;
 696                        param->target_count = dm_table_get_num_targets(table);
 697                        dm_table_put(table);
 698                }
 699        }
 700}
 701
 702static int dev_create(struct dm_ioctl *param, size_t param_size)
 703{
 704        int r, m = DM_ANY_MINOR;
 705        struct mapped_device *md;
 706
 707        r = check_name(param->name);
 708        if (r)
 709                return r;
 710
 711        if (param->flags & DM_PERSISTENT_DEV_FLAG)
 712                m = MINOR(huge_decode_dev(param->dev));
 713
 714        r = dm_create(m, &md);
 715        if (r)
 716                return r;
 717
 718        r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
 719        if (r) {
 720                dm_put(md);
 721                dm_destroy(md);
 722                return r;
 723        }
 724
 725        param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 726
 727        __dev_status(md, param);
 728
 729        dm_put(md);
 730
 731        return 0;
 732}
 733
 734/*
 735 * Always use UUID for lookups if it's present, otherwise use name or dev.
 736 */
 737static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
 738{
 739        struct hash_cell *hc = NULL;
 740
 741        if (*param->uuid) {
 742                if (*param->name || param->dev)
 743                        return NULL;
 744
 745                hc = __get_uuid_cell(param->uuid);
 746                if (!hc)
 747                        return NULL;
 748        } else if (*param->name) {
 749                if (param->dev)
 750                        return NULL;
 751
 752                hc = __get_name_cell(param->name);
 753                if (!hc)
 754                        return NULL;
 755        } else if (param->dev) {
 756                hc = __get_dev_cell(param->dev);
 757                if (!hc)
 758                        return NULL;
 759        } else
 760                return NULL;
 761
 762        /*
 763         * Sneakily write in both the name and the uuid
 764         * while we have the cell.
 765         */
 766        strlcpy(param->name, hc->name, sizeof(param->name));
 767        if (hc->uuid)
 768                strlcpy(param->uuid, hc->uuid, sizeof(param->uuid));
 769        else
 770                param->uuid[0] = '\0';
 771
 772        if (hc->new_map)
 773                param->flags |= DM_INACTIVE_PRESENT_FLAG;
 774        else
 775                param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 776
 777        return hc;
 778}
 779
 780static struct mapped_device *find_device(struct dm_ioctl *param)
 781{
 782        struct hash_cell *hc;
 783        struct mapped_device *md = NULL;
 784
 785        down_read(&_hash_lock);
 786        hc = __find_device_hash_cell(param);
 787        if (hc)
 788                md = hc->md;
 789        up_read(&_hash_lock);
 790
 791        return md;
 792}
 793
 794static int dev_remove(struct dm_ioctl *param, size_t param_size)
 795{
 796        struct hash_cell *hc;
 797        struct mapped_device *md;
 798        int r;
 799
 800        down_write(&_hash_lock);
 801        hc = __find_device_hash_cell(param);
 802
 803        if (!hc) {
 804                DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table.");
 805                up_write(&_hash_lock);
 806                return -ENXIO;
 807        }
 808
 809        md = hc->md;
 810
 811        /*
 812         * Ensure the device is not open and nothing further can open it.
 813         */
 814        r = dm_lock_for_deletion(md);
 815        if (r) {
 816                DMDEBUG_LIMIT("unable to remove open device %s", hc->name);
 817                up_write(&_hash_lock);
 818                dm_put(md);
 819                return r;
 820        }
 821
 822        __hash_remove(hc);
 823        up_write(&_hash_lock);
 824
 825        if (!dm_kobject_uevent(md, KOBJ_REMOVE, param->event_nr))
 826                param->flags |= DM_UEVENT_GENERATED_FLAG;
 827
 828        dm_put(md);
 829        dm_destroy(md);
 830        return 0;
 831}
 832
 833/*
 834 * Check a string doesn't overrun the chunk of
 835 * memory we copied from userland.
 836 */
 837static int invalid_str(char *str, void *end)
 838{
 839        while ((void *) str < end)
 840                if (!*str++)
 841                        return 0;
 842
 843        return -EINVAL;
 844}
 845
 846static int dev_rename(struct dm_ioctl *param, size_t param_size)
 847{
 848        int r;
 849        char *new_data = (char *) param + param->data_start;
 850        struct mapped_device *md;
 851        unsigned change_uuid = (param->flags & DM_UUID_FLAG) ? 1 : 0;
 852
 853        if (new_data < param->data ||
 854            invalid_str(new_data, (void *) param + param_size) ||
 855            strlen(new_data) > (change_uuid ? DM_UUID_LEN - 1 : DM_NAME_LEN - 1)) {
 856                DMWARN("Invalid new mapped device name or uuid string supplied.");
 857                return -EINVAL;
 858        }
 859
 860        if (!change_uuid) {
 861                r = check_name(new_data);
 862                if (r)
 863                        return r;
 864        }
 865
 866        md = dm_hash_rename(param, new_data);
 867        if (IS_ERR(md))
 868                return PTR_ERR(md);
 869
 870        __dev_status(md, param);
 871        dm_put(md);
 872
 873        return 0;
 874}
 875
 876static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
 877{
 878        int r = -EINVAL, x;
 879        struct mapped_device *md;
 880        struct hd_geometry geometry;
 881        unsigned long indata[4];
 882        char *geostr = (char *) param + param->data_start;
 883        char dummy;
 884
 885        md = find_device(param);
 886        if (!md)
 887                return -ENXIO;
 888
 889        if (geostr < param->data ||
 890            invalid_str(geostr, (void *) param + param_size)) {
 891                DMWARN("Invalid geometry supplied.");
 892                goto out;
 893        }
 894
 895        x = sscanf(geostr, "%lu %lu %lu %lu%c", indata,
 896                   indata + 1, indata + 2, indata + 3, &dummy);
 897
 898        if (x != 4) {
 899                DMWARN("Unable to interpret geometry settings.");
 900                goto out;
 901        }
 902
 903        if (indata[0] > 65535 || indata[1] > 255 ||
 904            indata[2] > 255 || indata[3] > ULONG_MAX) {
 905                DMWARN("Geometry exceeds range limits.");
 906                goto out;
 907        }
 908
 909        geometry.cylinders = indata[0];
 910        geometry.heads = indata[1];
 911        geometry.sectors = indata[2];
 912        geometry.start = indata[3];
 913
 914        r = dm_set_geometry(md, &geometry);
 915
 916        param->data_size = 0;
 917
 918out:
 919        dm_put(md);
 920        return r;
 921}
 922
 923static int do_suspend(struct dm_ioctl *param)
 924{
 925        int r = 0;
 926        unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
 927        struct mapped_device *md;
 928
 929        md = find_device(param);
 930        if (!md)
 931                return -ENXIO;
 932
 933        if (param->flags & DM_SKIP_LOCKFS_FLAG)
 934                suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
 935        if (param->flags & DM_NOFLUSH_FLAG)
 936                suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
 937
 938        if (!dm_suspended_md(md)) {
 939                r = dm_suspend(md, suspend_flags);
 940                if (r)
 941                        goto out;
 942        }
 943
 944        __dev_status(md, param);
 945
 946out:
 947        dm_put(md);
 948
 949        return r;
 950}
 951
 952static int do_resume(struct dm_ioctl *param)
 953{
 954        int r = 0;
 955        unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
 956        struct hash_cell *hc;
 957        struct mapped_device *md;
 958        struct dm_table *new_map, *old_map = NULL;
 959
 960        down_write(&_hash_lock);
 961
 962        hc = __find_device_hash_cell(param);
 963        if (!hc) {
 964                DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table.");
 965                up_write(&_hash_lock);
 966                return -ENXIO;
 967        }
 968
 969        md = hc->md;
 970
 971        new_map = hc->new_map;
 972        hc->new_map = NULL;
 973        param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 974
 975        up_write(&_hash_lock);
 976
 977        /* Do we need to load a new map ? */
 978        if (new_map) {
 979                /* Suspend if it isn't already suspended */
 980                if (param->flags & DM_SKIP_LOCKFS_FLAG)
 981                        suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
 982                if (param->flags & DM_NOFLUSH_FLAG)
 983                        suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
 984                if (!dm_suspended_md(md))
 985                        dm_suspend(md, suspend_flags);
 986
 987                old_map = dm_swap_table(md, new_map);
 988                if (IS_ERR(old_map)) {
 989                        dm_table_destroy(new_map);
 990                        dm_put(md);
 991                        return PTR_ERR(old_map);
 992                }
 993
 994                if (dm_table_get_mode(new_map) & FMODE_WRITE)
 995                        set_disk_ro(dm_disk(md), 0);
 996                else
 997                        set_disk_ro(dm_disk(md), 1);
 998        }
 999
1000        if (dm_suspended_md(md)) {
1001                r = dm_resume(md);
1002                if (!r && !dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr))
1003                        param->flags |= DM_UEVENT_GENERATED_FLAG;
1004        }
1005
1006        if (old_map)
1007                dm_table_destroy(old_map);
1008
1009        if (!r)
1010                __dev_status(md, param);
1011
1012        dm_put(md);
1013        return r;
1014}
1015
1016/*
1017 * Set or unset the suspension state of a device.
1018 * If the device already is in the requested state we just return its status.
1019 */
1020static int dev_suspend(struct dm_ioctl *param, size_t param_size)
1021{
1022        if (param->flags & DM_SUSPEND_FLAG)
1023                return do_suspend(param);
1024
1025        return do_resume(param);
1026}
1027
1028/*
1029 * Copies device info back to user space, used by
1030 * the create and info ioctls.
1031 */
1032static int dev_status(struct dm_ioctl *param, size_t param_size)
1033{
1034        struct mapped_device *md;
1035
1036        md = find_device(param);
1037        if (!md)
1038                return -ENXIO;
1039
1040        __dev_status(md, param);
1041        dm_put(md);
1042
1043        return 0;
1044}
1045
1046/*
1047 * Build up the status struct for each target
1048 */
1049static void retrieve_status(struct dm_table *table,
1050                            struct dm_ioctl *param, size_t param_size)
1051{
1052        unsigned int i, num_targets;
1053        struct dm_target_spec *spec;
1054        char *outbuf, *outptr;
1055        status_type_t type;
1056        size_t remaining, len, used = 0;
1057        unsigned status_flags = 0;
1058
1059        outptr = outbuf = get_result_buffer(param, param_size, &len);
1060
1061        if (param->flags & DM_STATUS_TABLE_FLAG)
1062                type = STATUSTYPE_TABLE;
1063        else
1064                type = STATUSTYPE_INFO;
1065
1066        /* Get all the target info */
1067        num_targets = dm_table_get_num_targets(table);
1068        for (i = 0; i < num_targets; i++) {
1069                struct dm_target *ti = dm_table_get_target(table, i);
1070                size_t l;
1071
1072                remaining = len - (outptr - outbuf);
1073                if (remaining <= sizeof(struct dm_target_spec)) {
1074                        param->flags |= DM_BUFFER_FULL_FLAG;
1075                        break;
1076                }
1077
1078                spec = (struct dm_target_spec *) outptr;
1079
1080                spec->status = 0;
1081                spec->sector_start = ti->begin;
1082                spec->length = ti->len;
1083                strncpy(spec->target_type, ti->type->name,
1084                        sizeof(spec->target_type));
1085
1086                outptr += sizeof(struct dm_target_spec);
1087                remaining = len - (outptr - outbuf);
1088                if (remaining <= 0) {
1089                        param->flags |= DM_BUFFER_FULL_FLAG;
1090                        break;
1091                }
1092
1093                /* Get the status/table string from the target driver */
1094                if (ti->type->status) {
1095                        if (param->flags & DM_NOFLUSH_FLAG)
1096                                status_flags |= DM_STATUS_NOFLUSH_FLAG;
1097                        ti->type->status(ti, type, status_flags, outptr, remaining);
1098                } else
1099                        outptr[0] = '\0';
1100
1101                l = strlen(outptr) + 1;
1102                if (l == remaining) {
1103                        param->flags |= DM_BUFFER_FULL_FLAG;
1104                        break;
1105                }
1106
1107                outptr += l;
1108                used = param->data_start + (outptr - outbuf);
1109
1110                outptr = align_ptr(outptr);
1111                spec->next = outptr - outbuf;
1112        }
1113
1114        if (used)
1115                param->data_size = used;
1116
1117        param->target_count = num_targets;
1118}
1119
1120/*
1121 * Wait for a device to report an event
1122 */
1123static int dev_wait(struct dm_ioctl *param, size_t param_size)
1124{
1125        int r = 0;
1126        struct mapped_device *md;
1127        struct dm_table *table;
1128
1129        md = find_device(param);
1130        if (!md)
1131                return -ENXIO;
1132
1133        /*
1134         * Wait for a notification event
1135         */
1136        if (dm_wait_event(md, param->event_nr)) {
1137                r = -ERESTARTSYS;
1138                goto out;
1139        }
1140
1141        /*
1142         * The userland program is going to want to know what
1143         * changed to trigger the event, so we may as well tell
1144         * him and save an ioctl.
1145         */
1146        __dev_status(md, param);
1147
1148        table = dm_get_live_or_inactive_table(md, param);
1149        if (table) {
1150                retrieve_status(table, param, param_size);
1151                dm_table_put(table);
1152        }
1153
1154out:
1155        dm_put(md);
1156
1157        return r;
1158}
1159
1160static inline fmode_t get_mode(struct dm_ioctl *param)
1161{
1162        fmode_t mode = FMODE_READ | FMODE_WRITE;
1163
1164        if (param->flags & DM_READONLY_FLAG)
1165                mode = FMODE_READ;
1166
1167        return mode;
1168}
1169
1170static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
1171                       struct dm_target_spec **spec, char **target_params)
1172{
1173        *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
1174        *target_params = (char *) (*spec + 1);
1175
1176        if (*spec < (last + 1))
1177                return -EINVAL;
1178
1179        return invalid_str(*target_params, end);
1180}
1181
1182static int populate_table(struct dm_table *table,
1183                          struct dm_ioctl *param, size_t param_size)
1184{
1185        int r;
1186        unsigned int i = 0;
1187        struct dm_target_spec *spec = (struct dm_target_spec *) param;
1188        uint32_t next = param->data_start;
1189        void *end = (void *) param + param_size;
1190        char *target_params;
1191
1192        if (!param->target_count) {
1193                DMWARN("populate_table: no targets specified");
1194                return -EINVAL;
1195        }
1196
1197        for (i = 0; i < param->target_count; i++) {
1198
1199                r = next_target(spec, next, end, &spec, &target_params);
1200                if (r) {
1201                        DMWARN("unable to find target");
1202                        return r;
1203                }
1204
1205                r = dm_table_add_target(table, spec->target_type,
1206                                        (sector_t) spec->sector_start,
1207                                        (sector_t) spec->length,
1208                                        target_params);
1209                if (r) {
1210                        DMWARN("error adding target to table");
1211                        return r;
1212                }
1213
1214                next = spec->next;
1215        }
1216
1217        return dm_table_complete(table);
1218}
1219
1220static int table_load(struct dm_ioctl *param, size_t param_size)
1221{
1222        int r;
1223        struct hash_cell *hc;
1224        struct dm_table *t;
1225        struct mapped_device *md;
1226        struct target_type *immutable_target_type;
1227
1228        md = find_device(param);
1229        if (!md)
1230                return -ENXIO;
1231
1232        r = dm_table_create(&t, get_mode(param), param->target_count, md);
1233        if (r)
1234                goto out;
1235
1236        r = populate_table(t, param, param_size);
1237        if (r) {
1238                dm_table_destroy(t);
1239                goto out;
1240        }
1241
1242        immutable_target_type = dm_get_immutable_target_type(md);
1243        if (immutable_target_type &&
1244            (immutable_target_type != dm_table_get_immutable_target_type(t))) {
1245                DMWARN("can't replace immutable target type %s",
1246                       immutable_target_type->name);
1247                dm_table_destroy(t);
1248                r = -EINVAL;
1249                goto out;
1250        }
1251
1252        /* Protect md->type and md->queue against concurrent table loads. */
1253        dm_lock_md_type(md);
1254        if (dm_get_md_type(md) == DM_TYPE_NONE)
1255                /* Initial table load: acquire type of table. */
1256                dm_set_md_type(md, dm_table_get_type(t));
1257        else if (dm_get_md_type(md) != dm_table_get_type(t)) {
1258                DMWARN("can't change device type after initial table load.");
1259                dm_table_destroy(t);
1260                dm_unlock_md_type(md);
1261                r = -EINVAL;
1262                goto out;
1263        }
1264
1265        /* setup md->queue to reflect md's type (may block) */
1266        r = dm_setup_md_queue(md);
1267        if (r) {
1268                DMWARN("unable to set up device queue for new table.");
1269                dm_table_destroy(t);
1270                dm_unlock_md_type(md);
1271                goto out;
1272        }
1273        dm_unlock_md_type(md);
1274
1275        /* stage inactive table */
1276        down_write(&_hash_lock);
1277        hc = dm_get_mdptr(md);
1278        if (!hc || hc->md != md) {
1279                DMWARN("device has been removed from the dev hash table.");
1280                dm_table_destroy(t);
1281                up_write(&_hash_lock);
1282                r = -ENXIO;
1283                goto out;
1284        }
1285
1286        if (hc->new_map)
1287                dm_table_destroy(hc->new_map);
1288        hc->new_map = t;
1289        up_write(&_hash_lock);
1290
1291        param->flags |= DM_INACTIVE_PRESENT_FLAG;
1292        __dev_status(md, param);
1293
1294out:
1295        dm_put(md);
1296
1297        return r;
1298}
1299
1300static int table_clear(struct dm_ioctl *param, size_t param_size)
1301{
1302        struct hash_cell *hc;
1303        struct mapped_device *md;
1304
1305        down_write(&_hash_lock);
1306
1307        hc = __find_device_hash_cell(param);
1308        if (!hc) {
1309                DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table.");
1310                up_write(&_hash_lock);
1311                return -ENXIO;
1312        }
1313
1314        if (hc->new_map) {
1315                dm_table_destroy(hc->new_map);
1316                hc->new_map = NULL;
1317        }
1318
1319        param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1320
1321        __dev_status(hc->md, param);
1322        md = hc->md;
1323        up_write(&_hash_lock);
1324        dm_put(md);
1325
1326        return 0;
1327}
1328
1329/*
1330 * Retrieves a list of devices used by a particular dm device.
1331 */
1332static void retrieve_deps(struct dm_table *table,
1333                          struct dm_ioctl *param, size_t param_size)
1334{
1335        unsigned int count = 0;
1336        struct list_head *tmp;
1337        size_t len, needed;
1338        struct dm_dev_internal *dd;
1339        struct dm_target_deps *deps;
1340
1341        deps = get_result_buffer(param, param_size, &len);
1342
1343        /*
1344         * Count the devices.
1345         */
1346        list_for_each (tmp, dm_table_get_devices(table))
1347                count++;
1348
1349        /*
1350         * Check we have enough space.
1351         */
1352        needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1353        if (len < needed) {
1354                param->flags |= DM_BUFFER_FULL_FLAG;
1355                return;
1356        }
1357
1358        /*
1359         * Fill in the devices.
1360         */
1361        deps->count = count;
1362        count = 0;
1363        list_for_each_entry (dd, dm_table_get_devices(table), list)
1364                deps->dev[count++] = huge_encode_dev(dd->dm_dev.bdev->bd_dev);
1365
1366        param->data_size = param->data_start + needed;
1367}
1368
1369static int table_deps(struct dm_ioctl *param, size_t param_size)
1370{
1371        struct mapped_device *md;
1372        struct dm_table *table;
1373
1374        md = find_device(param);
1375        if (!md)
1376                return -ENXIO;
1377
1378        __dev_status(md, param);
1379
1380        table = dm_get_live_or_inactive_table(md, param);
1381        if (table) {
1382                retrieve_deps(table, param, param_size);
1383                dm_table_put(table);
1384        }
1385
1386        dm_put(md);
1387
1388        return 0;
1389}
1390
1391/*
1392 * Return the status of a device as a text string for each
1393 * target.
1394 */
1395static int table_status(struct dm_ioctl *param, size_t param_size)
1396{
1397        struct mapped_device *md;
1398        struct dm_table *table;
1399
1400        md = find_device(param);
1401        if (!md)
1402                return -ENXIO;
1403
1404        __dev_status(md, param);
1405
1406        table = dm_get_live_or_inactive_table(md, param);
1407        if (table) {
1408                retrieve_status(table, param, param_size);
1409                dm_table_put(table);
1410        }
1411
1412        dm_put(md);
1413
1414        return 0;
1415}
1416
1417static bool buffer_test_overflow(char *result, unsigned maxlen)
1418{
1419        return !maxlen || strlen(result) + 1 >= maxlen;
1420}
1421
1422/*
1423 * Process device-mapper dependent messages.
1424 * Returns a number <= 1 if message was processed by device mapper.
1425 * Returns 2 if message should be delivered to the target.
1426 */
1427static int message_for_md(struct mapped_device *md, unsigned argc, char **argv,
1428                          char *result, unsigned maxlen)
1429{
1430        return 2;
1431}
1432
1433/*
1434 * Pass a message to the target that's at the supplied device offset.
1435 */
1436static int target_message(struct dm_ioctl *param, size_t param_size)
1437{
1438        int r, argc;
1439        char **argv;
1440        struct mapped_device *md;
1441        struct dm_table *table;
1442        struct dm_target *ti;
1443        struct dm_target_msg *tmsg = (void *) param + param->data_start;
1444        size_t maxlen;
1445        char *result = get_result_buffer(param, param_size, &maxlen);
1446
1447        md = find_device(param);
1448        if (!md)
1449                return -ENXIO;
1450
1451        if (tmsg < (struct dm_target_msg *) param->data ||
1452            invalid_str(tmsg->message, (void *) param + param_size)) {
1453                DMWARN("Invalid target message parameters.");
1454                r = -EINVAL;
1455                goto out;
1456        }
1457
1458        r = dm_split_args(&argc, &argv, tmsg->message);
1459        if (r) {
1460                DMWARN("Failed to split target message parameters");
1461                goto out;
1462        }
1463
1464        if (!argc) {
1465                DMWARN("Empty message received.");
1466                goto out_argv;
1467        }
1468
1469        r = message_for_md(md, argc, argv, result, maxlen);
1470        if (r <= 1)
1471                goto out_argv;
1472
1473        table = dm_get_live_table(md);
1474        if (!table)
1475                goto out_argv;
1476
1477        if (dm_deleting_md(md)) {
1478                r = -ENXIO;
1479                goto out_table;
1480        }
1481
1482        ti = dm_table_find_target(table, tmsg->sector);
1483        if (!dm_target_is_valid(ti)) {
1484                DMWARN("Target message sector outside device.");
1485                r = -EINVAL;
1486        } else if (ti->type->message)
1487                r = ti->type->message(ti, argc, argv);
1488        else {
1489                DMWARN("Target type does not support messages");
1490                r = -EINVAL;
1491        }
1492
1493 out_table:
1494        dm_table_put(table);
1495 out_argv:
1496        kfree(argv);
1497 out:
1498        if (r >= 0)
1499                __dev_status(md, param);
1500
1501        if (r == 1) {
1502                param->flags |= DM_DATA_OUT_FLAG;
1503                if (buffer_test_overflow(result, maxlen))
1504                        param->flags |= DM_BUFFER_FULL_FLAG;
1505                else
1506                        param->data_size = param->data_start + strlen(result) + 1;
1507                r = 0;
1508        }
1509
1510        dm_put(md);
1511        return r;
1512}
1513
1514/*
1515 * The ioctl parameter block consists of two parts, a dm_ioctl struct
1516 * followed by a data buffer.  This flag is set if the second part,
1517 * which has a variable size, is not used by the function processing
1518 * the ioctl.
1519 */
1520#define IOCTL_FLAGS_NO_PARAMS   1
1521
1522/*-----------------------------------------------------------------
1523 * Implementation of open/close/ioctl on the special char
1524 * device.
1525 *---------------------------------------------------------------*/
1526static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags)
1527{
1528        static struct {
1529                int cmd;
1530                int flags;
1531                ioctl_fn fn;
1532        } _ioctls[] = {
1533                {DM_VERSION_CMD, 0, NULL}, /* version is dealt with elsewhere */
1534                {DM_REMOVE_ALL_CMD, IOCTL_FLAGS_NO_PARAMS, remove_all},
1535                {DM_LIST_DEVICES_CMD, 0, list_devices},
1536
1537                {DM_DEV_CREATE_CMD, IOCTL_FLAGS_NO_PARAMS, dev_create},
1538                {DM_DEV_REMOVE_CMD, IOCTL_FLAGS_NO_PARAMS, dev_remove},
1539                {DM_DEV_RENAME_CMD, 0, dev_rename},
1540                {DM_DEV_SUSPEND_CMD, IOCTL_FLAGS_NO_PARAMS, dev_suspend},
1541                {DM_DEV_STATUS_CMD, IOCTL_FLAGS_NO_PARAMS, dev_status},
1542                {DM_DEV_WAIT_CMD, 0, dev_wait},
1543
1544                {DM_TABLE_LOAD_CMD, 0, table_load},
1545                {DM_TABLE_CLEAR_CMD, IOCTL_FLAGS_NO_PARAMS, table_clear},
1546                {DM_TABLE_DEPS_CMD, 0, table_deps},
1547                {DM_TABLE_STATUS_CMD, 0, table_status},
1548
1549                {DM_LIST_VERSIONS_CMD, 0, list_versions},
1550
1551                {DM_TARGET_MSG_CMD, 0, target_message},
1552                {DM_DEV_SET_GEOMETRY_CMD, 0, dev_set_geometry}
1553        };
1554
1555        if (unlikely(cmd >= ARRAY_SIZE(_ioctls)))
1556                return NULL;
1557
1558        *ioctl_flags = _ioctls[cmd].flags;
1559        return _ioctls[cmd].fn;
1560}
1561
1562/*
1563 * As well as checking the version compatibility this always
1564 * copies the kernel interface version out.
1565 */
1566static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1567{
1568        uint32_t version[3];
1569        int r = 0;
1570
1571        if (copy_from_user(version, user->version, sizeof(version)))
1572                return -EFAULT;
1573
1574        if ((DM_VERSION_MAJOR != version[0]) ||
1575            (DM_VERSION_MINOR < version[1])) {
1576                DMWARN("ioctl interface mismatch: "
1577                       "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1578                       DM_VERSION_MAJOR, DM_VERSION_MINOR,
1579                       DM_VERSION_PATCHLEVEL,
1580                       version[0], version[1], version[2], cmd);
1581                r = -EINVAL;
1582        }
1583
1584        /*
1585         * Fill in the kernel version.
1586         */
1587        version[0] = DM_VERSION_MAJOR;
1588        version[1] = DM_VERSION_MINOR;
1589        version[2] = DM_VERSION_PATCHLEVEL;
1590        if (copy_to_user(user->version, version, sizeof(version)))
1591                return -EFAULT;
1592
1593        return r;
1594}
1595
1596#define DM_PARAMS_KMALLOC       0x0001  /* Params alloced with kmalloc */
1597#define DM_PARAMS_VMALLOC       0x0002  /* Params alloced with vmalloc */
1598#define DM_WIPE_BUFFER          0x0010  /* Wipe input buffer before returning from ioctl */
1599
1600static void free_params(struct dm_ioctl *param, size_t param_size, int param_flags)
1601{
1602        if (param_flags & DM_WIPE_BUFFER)
1603                memset(param, 0, param_size);
1604
1605        if (param_flags & DM_PARAMS_KMALLOC)
1606                kfree(param);
1607        if (param_flags & DM_PARAMS_VMALLOC)
1608                vfree(param);
1609}
1610
1611static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kernel,
1612                       int ioctl_flags,
1613                       struct dm_ioctl **param, int *param_flags)
1614{
1615        struct dm_ioctl *dmi;
1616        int secure_data;
1617        const size_t minimum_data_size = sizeof(*param_kernel) - sizeof(param_kernel->data);
1618
1619        if (copy_from_user(param_kernel, user, minimum_data_size))
1620                return -EFAULT;
1621
1622        if (param_kernel->data_size < minimum_data_size)
1623                return -EINVAL;
1624
1625        secure_data = param_kernel->flags & DM_SECURE_DATA_FLAG;
1626
1627        *param_flags = secure_data ? DM_WIPE_BUFFER : 0;
1628
1629        if (ioctl_flags & IOCTL_FLAGS_NO_PARAMS) {
1630                dmi = param_kernel;
1631                dmi->data_size = minimum_data_size;
1632                goto data_copied;
1633        }
1634
1635        /*
1636         * Try to avoid low memory issues when a device is suspended.
1637         * Use kmalloc() rather than vmalloc() when we can.
1638         */
1639        dmi = NULL;
1640        if (param_kernel->data_size <= KMALLOC_MAX_SIZE) {
1641                dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
1642                if (dmi)
1643                        *param_flags |= DM_PARAMS_KMALLOC;
1644        }
1645
1646        if (!dmi) {
1647                dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_REPEAT | __GFP_HIGH, PAGE_KERNEL);
1648                if (dmi)
1649                        *param_flags |= DM_PARAMS_VMALLOC;
1650        }
1651
1652        if (!dmi) {
1653                if (secure_data && clear_user(user, param_kernel->data_size))
1654                        return -EFAULT;
1655                return -ENOMEM;
1656        }
1657
1658        if (copy_from_user(dmi, user, param_kernel->data_size))
1659                goto bad;
1660
1661data_copied:
1662        /*
1663         * Abort if something changed the ioctl data while it was being copied.
1664         */
1665        if (dmi->data_size != param_kernel->data_size) {
1666                DMERR("rejecting ioctl: data size modified while processing parameters");
1667                goto bad;
1668        }
1669
1670        /* Wipe the user buffer so we do not return it to userspace */
1671        if (secure_data && clear_user(user, param_kernel->data_size))
1672                goto bad;
1673
1674        *param = dmi;
1675        return 0;
1676
1677bad:
1678        free_params(dmi, param_kernel->data_size, *param_flags);
1679
1680        return -EFAULT;
1681}
1682
1683static int validate_params(uint cmd, struct dm_ioctl *param)
1684{
1685        /* Always clear this flag */
1686        param->flags &= ~DM_BUFFER_FULL_FLAG;
1687        param->flags &= ~DM_UEVENT_GENERATED_FLAG;
1688        param->flags &= ~DM_SECURE_DATA_FLAG;
1689        param->flags &= ~DM_DATA_OUT_FLAG;
1690
1691        /* Ignores parameters */
1692        if (cmd == DM_REMOVE_ALL_CMD ||
1693            cmd == DM_LIST_DEVICES_CMD ||
1694            cmd == DM_LIST_VERSIONS_CMD)
1695                return 0;
1696
1697        if ((cmd == DM_DEV_CREATE_CMD)) {
1698                if (!*param->name) {
1699                        DMWARN("name not supplied when creating device");
1700                        return -EINVAL;
1701                }
1702        } else if ((*param->uuid && *param->name)) {
1703                DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1704                return -EINVAL;
1705        }
1706
1707        /* Ensure strings are terminated */
1708        param->name[DM_NAME_LEN - 1] = '\0';
1709        param->uuid[DM_UUID_LEN - 1] = '\0';
1710
1711        return 0;
1712}
1713
1714static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
1715{
1716        int r = 0;
1717        int ioctl_flags;
1718        int param_flags;
1719        unsigned int cmd;
1720        struct dm_ioctl *uninitialized_var(param);
1721        ioctl_fn fn = NULL;
1722        size_t input_param_size;
1723        struct dm_ioctl param_kernel;
1724
1725        /* only root can play with this */
1726        if (!capable(CAP_SYS_ADMIN))
1727                return -EACCES;
1728
1729        if (_IOC_TYPE(command) != DM_IOCTL)
1730                return -ENOTTY;
1731
1732        cmd = _IOC_NR(command);
1733
1734        /*
1735         * Check the interface version passed in.  This also
1736         * writes out the kernel's interface version.
1737         */
1738        r = check_version(cmd, user);
1739        if (r)
1740                return r;
1741
1742        /*
1743         * Nothing more to do for the version command.
1744         */
1745        if (cmd == DM_VERSION_CMD)
1746                return 0;
1747
1748        fn = lookup_ioctl(cmd, &ioctl_flags);
1749        if (!fn) {
1750                DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1751                return -ENOTTY;
1752        }
1753
1754        /*
1755         * Copy the parameters into kernel space.
1756         */
1757        r = copy_params(user, &param_kernel, ioctl_flags, &param, &param_flags);
1758
1759        if (r)
1760                return r;
1761
1762        input_param_size = param->data_size;
1763        r = validate_params(cmd, param);
1764        if (r)
1765                goto out;
1766
1767        param->data_size = sizeof(*param);
1768        r = fn(param, input_param_size);
1769
1770        if (unlikely(param->flags & DM_BUFFER_FULL_FLAG) &&
1771            unlikely(ioctl_flags & IOCTL_FLAGS_NO_PARAMS))
1772                DMERR("ioctl %d tried to output some data but has IOCTL_FLAGS_NO_PARAMS set", cmd);
1773
1774        /*
1775         * Copy the results back to userland.
1776         */
1777        if (!r && copy_to_user(user, param, param->data_size))
1778                r = -EFAULT;
1779
1780out:
1781        free_params(param, input_param_size, param_flags);
1782        return r;
1783}
1784
1785static long dm_ctl_ioctl(struct file *file, uint command, ulong u)
1786{
1787        return (long)ctl_ioctl(command, (struct dm_ioctl __user *)u);
1788}
1789
1790#ifdef CONFIG_COMPAT
1791static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u)
1792{
1793        return (long)dm_ctl_ioctl(file, command, (ulong) compat_ptr(u));
1794}
1795#else
1796#define dm_compat_ctl_ioctl NULL
1797#endif
1798
1799static const struct file_operations _ctl_fops = {
1800        .open = nonseekable_open,
1801        .unlocked_ioctl  = dm_ctl_ioctl,
1802        .compat_ioctl = dm_compat_ctl_ioctl,
1803        .owner   = THIS_MODULE,
1804        .llseek  = noop_llseek,
1805};
1806
1807static struct miscdevice _dm_misc = {
1808        .minor          = MAPPER_CTRL_MINOR,
1809        .name           = DM_NAME,
1810        .nodename       = DM_DIR "/" DM_CONTROL_NODE,
1811        .fops           = &_ctl_fops
1812};
1813
1814MODULE_ALIAS_MISCDEV(MAPPER_CTRL_MINOR);
1815MODULE_ALIAS("devname:" DM_DIR "/" DM_CONTROL_NODE);
1816
1817/*
1818 * Create misc character device and link to DM_DIR/control.
1819 */
1820int __init dm_interface_init(void)
1821{
1822        int r;
1823
1824        r = dm_hash_init();
1825        if (r)
1826                return r;
1827
1828        r = misc_register(&_dm_misc);
1829        if (r) {
1830                DMERR("misc_register failed for control device");
1831                dm_hash_exit();
1832                return r;
1833        }
1834
1835        DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1836               DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1837               DM_DRIVER_EMAIL);
1838        return 0;
1839}
1840
1841void dm_interface_exit(void)
1842{
1843        if (misc_deregister(&_dm_misc) < 0)
1844                DMERR("misc_deregister failed for control device");
1845
1846        dm_hash_exit();
1847}
1848
1849/**
1850 * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers
1851 * @md: Pointer to mapped_device
1852 * @name: Buffer (size DM_NAME_LEN) for name
1853 * @uuid: Buffer (size DM_UUID_LEN) for uuid or empty string if uuid not defined
1854 */
1855int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
1856{
1857        int r = 0;
1858        struct hash_cell *hc;
1859
1860        if (!md)
1861                return -ENXIO;
1862
1863        mutex_lock(&dm_hash_cells_mutex);
1864        hc = dm_get_mdptr(md);
1865        if (!hc || hc->md != md) {
1866                r = -ENXIO;
1867                goto out;
1868        }
1869
1870        if (name)
1871                strcpy(name, hc->name);
1872        if (uuid)
1873                strcpy(uuid, hc->uuid ? : "");
1874
1875out:
1876        mutex_unlock(&dm_hash_cells_mutex);
1877
1878        return r;
1879}
1880
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