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
 884        md = find_device(param);
 885        if (!md)
 886                return -ENXIO;
 887
 888        if (geostr < param->data ||
 889            invalid_str(geostr, (void *) param + param_size)) {
 890                DMWARN("Invalid geometry supplied.");
 891                goto out;
 892        }
 893
 894        x = sscanf(geostr, "%lu %lu %lu %lu", indata,
 895                   indata + 1, indata + 2, indata + 3);
 896
 897        if (x != 4) {
 898                DMWARN("Unable to interpret geometry settings.");
 899                goto out;
 900        }
 901
 902        if (indata[0] > 65535 || indata[1] > 255 ||
 903            indata[2] > 255 || indata[3] > ULONG_MAX) {
 904                DMWARN("Geometry exceeds range limits.");
 905                goto out;
 906        }
 907
 908        geometry.cylinders = indata[0];
 909        geometry.heads = indata[1];
 910        geometry.sectors = indata[2];
 911        geometry.start = indata[3];
 912
 913        r = dm_set_geometry(md, &geometry);
 914
 915        param->data_size = 0;
 916
 917out:
 918        dm_put(md);
 919        return r;
 920}
 921
 922static int do_suspend(struct dm_ioctl *param)
 923{
 924        int r = 0;
 925        unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
 926        struct mapped_device *md;
 927
 928        md = find_device(param);
 929        if (!md)
 930                return -ENXIO;
 931
 932        if (param->flags & DM_SKIP_LOCKFS_FLAG)
 933                suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
 934        if (param->flags & DM_NOFLUSH_FLAG)
 935                suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
 936
 937        if (!dm_suspended_md(md)) {
 938                r = dm_suspend(md, suspend_flags);
 939                if (r)
 940                        goto out;
 941        }
 942
 943        __dev_status(md, param);
 944
 945out:
 946        dm_put(md);
 947
 948        return r;
 949}
 950
 951static int do_resume(struct dm_ioctl *param)
 952{
 953        int r = 0;
 954        unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
 955        struct hash_cell *hc;
 956        struct mapped_device *md;
 957        struct dm_table *new_map, *old_map = NULL;
 958
 959        down_write(&_hash_lock);
 960
 961        hc = __find_device_hash_cell(param);
 962        if (!hc) {
 963                DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table.");
 964                up_write(&_hash_lock);
 965                return -ENXIO;
 966        }
 967
 968        md = hc->md;
 969
 970        new_map = hc->new_map;
 971        hc->new_map = NULL;
 972        param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 973
 974        up_write(&_hash_lock);
 975
 976        /* Do we need to load a new map ? */
 977        if (new_map) {
 978                /* Suspend if it isn't already suspended */
 979                if (param->flags & DM_SKIP_LOCKFS_FLAG)
 980                        suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
 981                if (param->flags & DM_NOFLUSH_FLAG)
 982                        suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
 983                if (!dm_suspended_md(md))
 984                        dm_suspend(md, suspend_flags);
 985
 986                old_map = dm_swap_table(md, new_map);
 987                if (IS_ERR(old_map)) {
 988                        dm_table_destroy(new_map);
 989                        dm_put(md);
 990                        return PTR_ERR(old_map);
 991                }
 992
 993                if (dm_table_get_mode(new_map) & FMODE_WRITE)
 994                        set_disk_ro(dm_disk(md), 0);
 995                else
 996                        set_disk_ro(dm_disk(md), 1);
 997        }
 998
 999        if (dm_suspended_md(md)) {
1000                r = dm_resume(md);
1001                if (!r && !dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr))
1002                        param->flags |= DM_UEVENT_GENERATED_FLAG;
1003        }
1004
1005        if (old_map)
1006                dm_table_destroy(old_map);
1007
1008        if (!r)
1009                __dev_status(md, param);
1010
1011        dm_put(md);
1012        return r;
1013}
1014
1015/*
1016 * Set or unset the suspension state of a device.
1017 * If the device already is in the requested state we just return its status.
1018 */
1019static int dev_suspend(struct dm_ioctl *param, size_t param_size)
1020{
1021        if (param->flags & DM_SUSPEND_FLAG)
1022                return do_suspend(param);
1023
1024        return do_resume(param);
1025}
1026
1027/*
1028 * Copies device info back to user space, used by
1029 * the create and info ioctls.
1030 */
1031static int dev_status(struct dm_ioctl *param, size_t param_size)
1032{
1033        struct mapped_device *md;
1034
1035        md = find_device(param);
1036        if (!md)
1037                return -ENXIO;
1038
1039        __dev_status(md, param);
1040        dm_put(md);
1041
1042        return 0;
1043}
1044
1045/*
1046 * Build up the status struct for each target
1047 */
1048static void retrieve_status(struct dm_table *table,
1049                            struct dm_ioctl *param, size_t param_size)
1050{
1051        unsigned int i, num_targets;
1052        struct dm_target_spec *spec;
1053        char *outbuf, *outptr;
1054        status_type_t type;
1055        size_t remaining, len, used = 0;
1056
1057        outptr = outbuf = get_result_buffer(param, param_size, &len);
1058
1059        if (param->flags & DM_STATUS_TABLE_FLAG)
1060                type = STATUSTYPE_TABLE;
1061        else
1062                type = STATUSTYPE_INFO;
1063
1064        /* Get all the target info */
1065        num_targets = dm_table_get_num_targets(table);
1066        for (i = 0; i < num_targets; i++) {
1067                struct dm_target *ti = dm_table_get_target(table, i);
1068
1069                remaining = len - (outptr - outbuf);
1070                if (remaining <= sizeof(struct dm_target_spec)) {
1071                        param->flags |= DM_BUFFER_FULL_FLAG;
1072                        break;
1073                }
1074
1075                spec = (struct dm_target_spec *) outptr;
1076
1077                spec->status = 0;
1078                spec->sector_start = ti->begin;
1079                spec->length = ti->len;
1080                strncpy(spec->target_type, ti->type->name,
1081                        sizeof(spec->target_type));
1082
1083                outptr += sizeof(struct dm_target_spec);
1084                remaining = len - (outptr - outbuf);
1085                if (remaining <= 0) {
1086                        param->flags |= DM_BUFFER_FULL_FLAG;
1087                        break;
1088                }
1089
1090                /* Get the status/table string from the target driver */
1091                if (ti->type->status) {
1092                        if (ti->type->status(ti, type, outptr, remaining)) {
1093                                param->flags |= DM_BUFFER_FULL_FLAG;
1094                                break;
1095                        }
1096                } else
1097                        outptr[0] = '\0';
1098
1099                outptr += strlen(outptr) + 1;
1100                used = param->data_start + (outptr - outbuf);
1101
1102                outptr = align_ptr(outptr);
1103                spec->next = outptr - outbuf;
1104        }
1105
1106        if (used)
1107                param->data_size = used;
1108
1109        param->target_count = num_targets;
1110}
1111
1112/*
1113 * Wait for a device to report an event
1114 */
1115static int dev_wait(struct dm_ioctl *param, size_t param_size)
1116{
1117        int r = 0;
1118        struct mapped_device *md;
1119        struct dm_table *table;
1120
1121        md = find_device(param);
1122        if (!md)
1123                return -ENXIO;
1124
1125        /*
1126         * Wait for a notification event
1127         */
1128        if (dm_wait_event(md, param->event_nr)) {
1129                r = -ERESTARTSYS;
1130                goto out;
1131        }
1132
1133        /*
1134         * The userland program is going to want to know what
1135         * changed to trigger the event, so we may as well tell
1136         * him and save an ioctl.
1137         */
1138        __dev_status(md, param);
1139
1140        table = dm_get_live_or_inactive_table(md, param);
1141        if (table) {
1142                retrieve_status(table, param, param_size);
1143                dm_table_put(table);
1144        }
1145
1146out:
1147        dm_put(md);
1148
1149        return r;
1150}
1151
1152static inline fmode_t get_mode(struct dm_ioctl *param)
1153{
1154        fmode_t mode = FMODE_READ | FMODE_WRITE;
1155
1156        if (param->flags & DM_READONLY_FLAG)
1157                mode = FMODE_READ;
1158
1159        return mode;
1160}
1161
1162static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
1163                       struct dm_target_spec **spec, char **target_params)
1164{
1165        *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
1166        *target_params = (char *) (*spec + 1);
1167
1168        if (*spec < (last + 1))
1169                return -EINVAL;
1170
1171        return invalid_str(*target_params, end);
1172}
1173
1174static int populate_table(struct dm_table *table,
1175                          struct dm_ioctl *param, size_t param_size)
1176{
1177        int r;
1178        unsigned int i = 0;
1179        struct dm_target_spec *spec = (struct dm_target_spec *) param;
1180        uint32_t next = param->data_start;
1181        void *end = (void *) param + param_size;
1182        char *target_params;
1183
1184        if (!param->target_count) {
1185                DMWARN("populate_table: no targets specified");
1186                return -EINVAL;
1187        }
1188
1189        for (i = 0; i < param->target_count; i++) {
1190
1191                r = next_target(spec, next, end, &spec, &target_params);
1192                if (r) {
1193                        DMWARN("unable to find target");
1194                        return r;
1195                }
1196
1197                r = dm_table_add_target(table, spec->target_type,
1198                                        (sector_t) spec->sector_start,
1199                                        (sector_t) spec->length,
1200                                        target_params);
1201                if (r) {
1202                        DMWARN("error adding target to table");
1203                        return r;
1204                }
1205
1206                next = spec->next;
1207        }
1208
1209        return dm_table_complete(table);
1210}
1211
1212static int table_load(struct dm_ioctl *param, size_t param_size)
1213{
1214        int r;
1215        struct hash_cell *hc;
1216        struct dm_table *t;
1217        struct mapped_device *md;
1218        struct target_type *immutable_target_type;
1219
1220        md = find_device(param);
1221        if (!md)
1222                return -ENXIO;
1223
1224        r = dm_table_create(&t, get_mode(param), param->target_count, md);
1225        if (r)
1226                goto out;
1227
1228        r = populate_table(t, param, param_size);
1229        if (r) {
1230                dm_table_destroy(t);
1231                goto out;
1232        }
1233
1234        immutable_target_type = dm_get_immutable_target_type(md);
1235        if (immutable_target_type &&
1236            (immutable_target_type != dm_table_get_immutable_target_type(t))) {
1237                DMWARN("can't replace immutable target type %s",
1238                       immutable_target_type->name);
1239                dm_table_destroy(t);
1240                r = -EINVAL;
1241                goto out;
1242        }
1243
1244        /* Protect md->type and md->queue against concurrent table loads. */
1245        dm_lock_md_type(md);
1246        if (dm_get_md_type(md) == DM_TYPE_NONE)
1247                /* Initial table load: acquire type of table. */
1248                dm_set_md_type(md, dm_table_get_type(t));
1249        else if (dm_get_md_type(md) != dm_table_get_type(t)) {
1250                DMWARN("can't change device type after initial table load.");
1251                dm_table_destroy(t);
1252                dm_unlock_md_type(md);
1253                r = -EINVAL;
1254                goto out;
1255        }
1256
1257        /* setup md->queue to reflect md's type (may block) */
1258        r = dm_setup_md_queue(md);
1259        if (r) {
1260                DMWARN("unable to set up device queue for new table.");
1261                dm_table_destroy(t);
1262                dm_unlock_md_type(md);
1263                goto out;
1264        }
1265        dm_unlock_md_type(md);
1266
1267        /* stage inactive table */
1268        down_write(&_hash_lock);
1269        hc = dm_get_mdptr(md);
1270        if (!hc || hc->md != md) {
1271                DMWARN("device has been removed from the dev hash table.");
1272                dm_table_destroy(t);
1273                up_write(&_hash_lock);
1274                r = -ENXIO;
1275                goto out;
1276        }
1277
1278        if (hc->new_map)
1279                dm_table_destroy(hc->new_map);
1280        hc->new_map = t;
1281        up_write(&_hash_lock);
1282
1283        param->flags |= DM_INACTIVE_PRESENT_FLAG;
1284        __dev_status(md, param);
1285
1286out:
1287        dm_put(md);
1288
1289        return r;
1290}
1291
1292static int table_clear(struct dm_ioctl *param, size_t param_size)
1293{
1294        struct hash_cell *hc;
1295        struct mapped_device *md;
1296
1297        down_write(&_hash_lock);
1298
1299        hc = __find_device_hash_cell(param);
1300        if (!hc) {
1301                DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table.");
1302                up_write(&_hash_lock);
1303                return -ENXIO;
1304        }
1305
1306        if (hc->new_map) {
1307                dm_table_destroy(hc->new_map);
1308                hc->new_map = NULL;
1309        }
1310
1311        param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1312
1313        __dev_status(hc->md, param);
1314        md = hc->md;
1315        up_write(&_hash_lock);
1316        dm_put(md);
1317
1318        return 0;
1319}
1320
1321/*
1322 * Retrieves a list of devices used by a particular dm device.
1323 */
1324static void retrieve_deps(struct dm_table *table,
1325                          struct dm_ioctl *param, size_t param_size)
1326{
1327        unsigned int count = 0;
1328        struct list_head *tmp;
1329        size_t len, needed;
1330        struct dm_dev_internal *dd;
1331        struct dm_target_deps *deps;
1332
1333        deps = get_result_buffer(param, param_size, &len);
1334
1335        /*
1336         * Count the devices.
1337         */
1338        list_for_each (tmp, dm_table_get_devices(table))
1339                count++;
1340
1341        /*
1342         * Check we have enough space.
1343         */
1344        needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1345        if (len < needed) {
1346                param->flags |= DM_BUFFER_FULL_FLAG;
1347                return;
1348        }
1349
1350        /*
1351         * Fill in the devices.
1352         */
1353        deps->count = count;
1354        count = 0;
1355        list_for_each_entry (dd, dm_table_get_devices(table), list)
1356                deps->dev[count++] = huge_encode_dev(dd->dm_dev.bdev->bd_dev);
1357
1358        param->data_size = param->data_start + needed;
1359}
1360
1361static int table_deps(struct dm_ioctl *param, size_t param_size)
1362{
1363        struct mapped_device *md;
1364        struct dm_table *table;
1365
1366        md = find_device(param);
1367        if (!md)
1368                return -ENXIO;
1369
1370        __dev_status(md, param);
1371
1372        table = dm_get_live_or_inactive_table(md, param);
1373        if (table) {
1374                retrieve_deps(table, param, param_size);
1375                dm_table_put(table);
1376        }
1377
1378        dm_put(md);
1379
1380        return 0;
1381}
1382
1383/*
1384 * Return the status of a device as a text string for each
1385 * target.
1386 */
1387static int table_status(struct dm_ioctl *param, size_t param_size)
1388{
1389        struct mapped_device *md;
1390        struct dm_table *table;
1391
1392        md = find_device(param);
1393        if (!md)
1394                return -ENXIO;
1395
1396        __dev_status(md, param);
1397
1398        table = dm_get_live_or_inactive_table(md, param);
1399        if (table) {
1400                retrieve_status(table, param, param_size);
1401                dm_table_put(table);
1402        }
1403
1404        dm_put(md);
1405
1406        return 0;
1407}
1408
1409/*
1410 * Pass a message to the target that's at the supplied device offset.
1411 */
1412static int target_message(struct dm_ioctl *param, size_t param_size)
1413{
1414        int r, argc;
1415        char **argv;
1416        struct mapped_device *md;
1417        struct dm_table *table;
1418        struct dm_target *ti;
1419        struct dm_target_msg *tmsg = (void *) param + param->data_start;
1420
1421        md = find_device(param);
1422        if (!md)
1423                return -ENXIO;
1424
1425        if (tmsg < (struct dm_target_msg *) param->data ||
1426            invalid_str(tmsg->message, (void *) param + param_size)) {
1427                DMWARN("Invalid target message parameters.");
1428                r = -EINVAL;
1429                goto out;
1430        }
1431
1432        r = dm_split_args(&argc, &argv, tmsg->message);
1433        if (r) {
1434                DMWARN("Failed to split target message parameters");
1435                goto out;
1436        }
1437
1438        if (!argc) {
1439                DMWARN("Empty message received.");
1440                goto out_argv;
1441        }
1442
1443        table = dm_get_live_table(md);
1444        if (!table)
1445                goto out_argv;
1446
1447        if (dm_deleting_md(md)) {
1448                r = -ENXIO;
1449                goto out_table;
1450        }
1451
1452        ti = dm_table_find_target(table, tmsg->sector);
1453        if (!dm_target_is_valid(ti)) {
1454                DMWARN("Target message sector outside device.");
1455                r = -EINVAL;
1456        } else if (ti->type->message)
1457                r = ti->type->message(ti, argc, argv);
1458        else {
1459                DMWARN("Target type does not support messages");
1460                r = -EINVAL;
1461        }
1462
1463 out_table:
1464        dm_table_put(table);
1465 out_argv:
1466        kfree(argv);
1467 out:
1468        param->data_size = 0;
1469        dm_put(md);
1470        return r;
1471}
1472
1473/*-----------------------------------------------------------------
1474 * Implementation of open/close/ioctl on the special char
1475 * device.
1476 *---------------------------------------------------------------*/
1477static ioctl_fn lookup_ioctl(unsigned int cmd)
1478{
1479        static struct {
1480                int cmd;
1481                ioctl_fn fn;
1482        } _ioctls[] = {
1483                {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
1484                {DM_REMOVE_ALL_CMD, remove_all},
1485                {DM_LIST_DEVICES_CMD, list_devices},
1486
1487                {DM_DEV_CREATE_CMD, dev_create},
1488                {DM_DEV_REMOVE_CMD, dev_remove},
1489                {DM_DEV_RENAME_CMD, dev_rename},
1490                {DM_DEV_SUSPEND_CMD, dev_suspend},
1491                {DM_DEV_STATUS_CMD, dev_status},
1492                {DM_DEV_WAIT_CMD, dev_wait},
1493
1494                {DM_TABLE_LOAD_CMD, table_load},
1495                {DM_TABLE_CLEAR_CMD, table_clear},
1496                {DM_TABLE_DEPS_CMD, table_deps},
1497                {DM_TABLE_STATUS_CMD, table_status},
1498
1499                {DM_LIST_VERSIONS_CMD, list_versions},
1500
1501                {DM_TARGET_MSG_CMD, target_message},
1502                {DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
1503        };
1504
1505        return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
1506}
1507
1508/*
1509 * As well as checking the version compatibility this always
1510 * copies the kernel interface version out.
1511 */
1512static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1513{
1514        uint32_t version[3];
1515        int r = 0;
1516
1517        if (copy_from_user(version, user->version, sizeof(version)))
1518                return -EFAULT;
1519
1520        if ((DM_VERSION_MAJOR != version[0]) ||
1521            (DM_VERSION_MINOR < version[1])) {
1522                DMWARN("ioctl interface mismatch: "
1523                       "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1524                       DM_VERSION_MAJOR, DM_VERSION_MINOR,
1525                       DM_VERSION_PATCHLEVEL,
1526                       version[0], version[1], version[2], cmd);
1527                r = -EINVAL;
1528        }
1529
1530        /*
1531         * Fill in the kernel version.
1532         */
1533        version[0] = DM_VERSION_MAJOR;
1534        version[1] = DM_VERSION_MINOR;
1535        version[2] = DM_VERSION_PATCHLEVEL;
1536        if (copy_to_user(user->version, version, sizeof(version)))
1537                return -EFAULT;
1538
1539        return r;
1540}
1541
1542static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
1543{
1544        struct dm_ioctl tmp, *dmi;
1545        int secure_data;
1546
1547        if (copy_from_user(&tmp, user, sizeof(tmp) - sizeof(tmp.data)))
1548                return -EFAULT;
1549
1550        if (tmp.data_size < (sizeof(tmp) - sizeof(tmp.data)))
1551                return -EINVAL;
1552
1553        secure_data = tmp.flags & DM_SECURE_DATA_FLAG;
1554
1555        dmi = vmalloc(tmp.data_size);
1556        if (!dmi) {
1557                if (secure_data && clear_user(user, tmp.data_size))
1558                        return -EFAULT;
1559                return -ENOMEM;
1560        }
1561
1562        if (copy_from_user(dmi, user, tmp.data_size))
1563                goto bad;
1564
1565        /* Wipe the user buffer so we do not return it to userspace */
1566        if (secure_data && clear_user(user, tmp.data_size))
1567                goto bad;
1568
1569        *param = dmi;
1570        return 0;
1571
1572bad:
1573        if (secure_data)
1574                memset(dmi, 0, tmp.data_size);
1575        vfree(dmi);
1576        return -EFAULT;
1577}
1578
1579static int validate_params(uint cmd, struct dm_ioctl *param)
1580{
1581        /* Always clear this flag */
1582        param->flags &= ~DM_BUFFER_FULL_FLAG;
1583        param->flags &= ~DM_UEVENT_GENERATED_FLAG;
1584        param->flags &= ~DM_SECURE_DATA_FLAG;
1585
1586        /* Ignores parameters */
1587        if (cmd == DM_REMOVE_ALL_CMD ||
1588            cmd == DM_LIST_DEVICES_CMD ||
1589            cmd == DM_LIST_VERSIONS_CMD)
1590                return 0;
1591
1592        if ((cmd == DM_DEV_CREATE_CMD)) {
1593                if (!*param->name) {
1594                        DMWARN("name not supplied when creating device");
1595                        return -EINVAL;
1596                }
1597        } else if ((*param->uuid && *param->name)) {
1598                DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1599                return -EINVAL;
1600        }
1601
1602        /* Ensure strings are terminated */
1603        param->name[DM_NAME_LEN - 1] = '\0';
1604        param->uuid[DM_UUID_LEN - 1] = '\0';
1605
1606        return 0;
1607}
1608
1609static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
1610{
1611        int r = 0;
1612        int wipe_buffer;
1613        unsigned int cmd;
1614        struct dm_ioctl *uninitialized_var(param);
1615        ioctl_fn fn = NULL;
1616        size_t input_param_size;
1617
1618        /* only root can play with this */
1619        if (!capable(CAP_SYS_ADMIN))
1620                return -EACCES;
1621
1622        if (_IOC_TYPE(command) != DM_IOCTL)
1623                return -ENOTTY;
1624
1625        cmd = _IOC_NR(command);
1626
1627        /*
1628         * Check the interface version passed in.  This also
1629         * writes out the kernel's interface version.
1630         */
1631        r = check_version(cmd, user);
1632        if (r)
1633                return r;
1634
1635        /*
1636         * Nothing more to do for the version command.
1637         */
1638        if (cmd == DM_VERSION_CMD)
1639                return 0;
1640
1641        fn = lookup_ioctl(cmd);
1642        if (!fn) {
1643                DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1644                return -ENOTTY;
1645        }
1646
1647        /*
1648         * Trying to avoid low memory issues when a device is
1649         * suspended.
1650         */
1651        current->flags |= PF_MEMALLOC;
1652
1653        /*
1654         * Copy the parameters into kernel space.
1655         */
1656        r = copy_params(user, &param);
1657
1658        current->flags &= ~PF_MEMALLOC;
1659
1660        if (r)
1661                return r;
1662
1663        input_param_size = param->data_size;
1664        wipe_buffer = param->flags & DM_SECURE_DATA_FLAG;
1665
1666        r = validate_params(cmd, param);
1667        if (r)
1668                goto out;
1669
1670        param->data_size = sizeof(*param);
1671        r = fn(param, input_param_size);
1672
1673        /*
1674         * Copy the results back to userland.
1675         */
1676        if (!r && copy_to_user(user, param, param->data_size))
1677                r = -EFAULT;
1678
1679out:
1680        if (wipe_buffer)
1681                memset(param, 0, input_param_size);
1682
1683        vfree(param);
1684        return r;
1685}
1686
1687static long dm_ctl_ioctl(struct file *file, uint command, ulong u)
1688{
1689        return (long)ctl_ioctl(command, (struct dm_ioctl __user *)u);
1690}
1691
1692#ifdef CONFIG_COMPAT
1693static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u)
1694{
1695        return (long)dm_ctl_ioctl(file, command, (ulong) compat_ptr(u));
1696}
1697#else
1698#define dm_compat_ctl_ioctl NULL
1699#endif
1700
1701static const struct file_operations _ctl_fops = {
1702        .open = nonseekable_open,
1703        .unlocked_ioctl  = dm_ctl_ioctl,
1704        .compat_ioctl = dm_compat_ctl_ioctl,
1705        .owner   = THIS_MODULE,
1706        .llseek  = noop_llseek,
1707};
1708
1709static struct miscdevice _dm_misc = {
1710        .minor          = MAPPER_CTRL_MINOR,
1711        .name           = DM_NAME,
1712        .nodename       = DM_DIR "/" DM_CONTROL_NODE,
1713        .fops           = &_ctl_fops
1714};
1715
1716MODULE_ALIAS_MISCDEV(MAPPER_CTRL_MINOR);
1717MODULE_ALIAS("devname:" DM_DIR "/" DM_CONTROL_NODE);
1718
1719/*
1720 * Create misc character device and link to DM_DIR/control.
1721 */
1722int __init dm_interface_init(void)
1723{
1724        int r;
1725
1726        r = dm_hash_init();
1727        if (r)
1728                return r;
1729
1730        r = misc_register(&_dm_misc);
1731        if (r) {
1732                DMERR("misc_register failed for control device");
1733                dm_hash_exit();
1734                return r;
1735        }
1736
1737        DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1738               DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1739               DM_DRIVER_EMAIL);
1740        return 0;
1741}
1742
1743void dm_interface_exit(void)
1744{
1745        if (misc_deregister(&_dm_misc) < 0)
1746                DMERR("misc_deregister failed for control device");
1747
1748        dm_hash_exit();
1749}
1750
1751/**
1752 * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers
1753 * @md: Pointer to mapped_device
1754 * @name: Buffer (size DM_NAME_LEN) for name
1755 * @uuid: Buffer (size DM_UUID_LEN) for uuid or empty string if uuid not defined
1756 */
1757int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
1758{
1759        int r = 0;
1760        struct hash_cell *hc;
1761
1762        if (!md)
1763                return -ENXIO;
1764
1765        mutex_lock(&dm_hash_cells_mutex);
1766        hc = dm_get_mdptr(md);
1767        if (!hc || hc->md != md) {
1768                r = -ENXIO;
1769                goto out;
1770        }
1771
1772        if (name)
1773                strcpy(name, hc->name);
1774        if (uuid)
1775                strcpy(uuid, hc->uuid ? : "");
1776
1777out:
1778        mutex_unlock(&dm_hash_cells_mutex);
1779
1780        return r;
1781}
1782