source4/dsdb/samdb/ldb_modules/schema_load.c

   1 /*
   2    Unix SMB/CIFS mplementation.
   3
   4    The module that handles the Schema FSMO Role Owner
   5    checkings, it also loads the dsdb_schema.
   6
   7    Copyright (C) Stefan Metzmacher <metze@samba.org> 2007
   8    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2009-2010
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 */
  24
  25 #include "includes.h"
  26 #include "ldb_module.h"
  27 #include "dsdb/samdb/samdb.h"
  28 #include "librpc/gen_ndr/ndr_misc.h"
  29 #include "librpc/gen_ndr/ndr_drsuapi.h"
  30 #include "librpc/gen_ndr/ndr_drsblobs.h"
  31 #include "param/param.h"
  32 #include "lib/tdb_wrap/tdb_wrap.h"
  33 #include "lib/tdb_compat/tdb_compat.h"
  34 #include "dsdb/samdb/ldb_modules/util.h"
  35
  36 #include "system/filesys.h"
  37 struct schema_load_private_data {
  38         bool in_transaction;
  39         struct tdb_wrap *metadata;
  40 };
  41
  42 static int dsdb_schema_from_db(struct ldb_module *module, struct ldb_dn *schema_dn, uint64_t current_usn,
  43                                struct dsdb_schema **schema);
  44
  45 /*
  46  * Open sam.ldb.d/metadata.tdb.
  47  */
  48 static int schema_metadata_open(struct ldb_module *module)
  49 {
  50         struct schema_load_private_data *data = talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
  51         struct ldb_context *ldb = ldb_module_get_ctx(module);
  52         TALLOC_CTX *tmp_ctx;
  53         struct loadparm_context *lp_ctx;
  54         const char *sam_name;
  55         char *filename;
  56         int open_flags;
  57         struct stat statbuf;
  58
  59         if (!data) {
  60                 return ldb_module_error(module, LDB_ERR_OPERATIONS_ERROR,
  61                                         "schema_load: metadata not initialized");
  62         }
  63         data->metadata = NULL;
  64
  65         tmp_ctx = talloc_new(NULL);
  66         if (tmp_ctx == NULL) {
  67                 return ldb_module_oom(module);
  68         }
  69
  70         sam_name = (const char *)ldb_get_opaque(ldb, "ldb_url");
  71         if (!sam_name) {
  72                 talloc_free(tmp_ctx);
  73                 return ldb_operr(ldb);
  74         }
  75         if (strncmp("tdb://", sam_name, 6) == 0) {
  76                 sam_name += 6;
  77         }
  78         filename = talloc_asprintf(tmp_ctx, "%s.d/metadata.tdb", sam_name);
  79         if (!filename) {
  80                 talloc_free(tmp_ctx);
  81                 return ldb_oom(ldb);
  82         }
  83
  84         open_flags = O_RDWR;
  85         if (stat(filename, &statbuf) != 0) {
  86                 talloc_free(tmp_ctx);
  87                 return LDB_ERR_OPERATIONS_ERROR;
  88         }
  89
  90         lp_ctx = talloc_get_type_abort(ldb_get_opaque(ldb, "loadparm"),
  91                                        struct loadparm_context);
  92
  93         data->metadata = tdb_wrap_open(data, filename, 10,
  94                                               TDB_DEFAULT, open_flags, 0660,
  95                                               lp_ctx);
  96         if (data->metadata == NULL) {
  97                 talloc_free(tmp_ctx);
  98                 return LDB_ERR_OPERATIONS_ERROR;
  99         }
 100
 101         talloc_free(tmp_ctx);
 102         return LDB_SUCCESS;
 103 }
 104
 105 static int schema_metadata_get_uint64(struct ldb_module *module,
 106                                          const char *key, uint64_t *value,
 107                                          uint64_t default_value)
 108 {
 109         struct schema_load_private_data *data = talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
 110         struct tdb_context *tdb;
 111         TDB_DATA tdb_key, tdb_data;
 112         char *value_str;
 113         TALLOC_CTX *tmp_ctx;
 114
 115         if (!data || !data->metadata) {
 116                 *value = default_value;
 117                 return LDB_SUCCESS;
 118         }
 119
 120         tmp_ctx = talloc_new(NULL);
 121         if (tmp_ctx == NULL) {
 122                 return ldb_module_oom(module);
 123         }
 124
 125         tdb = data->metadata->tdb;
 126
 127         tdb_key.dptr = (uint8_t *)discard_const_p(char, key);
 128         tdb_key.dsize = strlen(key);
 129
 130         tdb_data = tdb_fetch_compat(tdb, tdb_key);
 131         if (!tdb_data.dptr) {
 132                 if (tdb_error(tdb) == TDB_ERR_NOEXIST) {
 133                         *value = default_value;
 134                         talloc_free(tmp_ctx);
 135                         return LDB_SUCCESS;
 136                 } else {
 137                         talloc_free(tmp_ctx);
 138                         return ldb_module_error(module, LDB_ERR_OPERATIONS_ERROR,
 139                                                 tdb_errorstr_compat(tdb));
 140                 }
 141         }
 142
 143         value_str = talloc_strndup(tmp_ctx, (char *)tdb_data.dptr, tdb_data.dsize);
 144         if (value_str == NULL) {
 145                 SAFE_FREE(tdb_data.dptr);
 146                 talloc_free(tmp_ctx);
 147                 return ldb_module_oom(module);
 148         }
 149
 150         *value = strtoull(value_str, NULL, 10);
 151
 152         SAFE_FREE(tdb_data.dptr);
 153         talloc_free(tmp_ctx);
 154
 155         return LDB_SUCCESS;
 156 }
 157
 158 static struct dsdb_schema *dsdb_schema_refresh(struct ldb_module *module, struct dsdb_schema *schema, bool is_global_schema)
 159 {
 160         uint64_t current_usn, value;
 161         int ret;
 162         struct ldb_context *ldb = ldb_module_get_ctx(module);
 163         struct dsdb_schema *new_schema;
 164         struct ldb_dn *schema_dn = ldb_get_schema_basedn(ldb);
 165         time_t ts, lastts;
 166
 167         struct schema_load_private_data *private_data = talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
 168         if (!private_data) {
 169                 /* We can't refresh until the init function has run */
 170                 return schema;
 171         }
 172
 173         /* We don't allow a schema reload during a transaction - nobody else can modify our schema behind our backs */
 174         if (private_data->in_transaction) {
 175                 return schema;
 176         }
 177
 178         lastts = schema->last_refresh;
 179         ts = time(NULL);
 180         if (lastts > (ts - schema->refresh_interval)) {
 181                 DEBUG(11, ("Less than %d seconds since last reload, returning cached version ts = %d\n", (int)schema->refresh_interval, (int)lastts));
 182                 return schema;
 183         }
 184
 185         /*
 186          * We update right now the last refresh timestamp so that if
 187          * the schema partition hasn't change we don't keep on retrying.
 188          * Otherwise if the timestamp was update only when the schema has
 189          * actually changed (and therefor completely reloaded) we would
 190          * continue to hit the database to get the highest USN.
 191          */
 192
 193         ret = schema_metadata_get_uint64(module, DSDB_METADATA_SCHEMA_SEQ_NUM, &value, 0);
 194         if (ret == LDB_SUCCESS) {
 195                 schema->metadata_usn = value;
 196         } else {
 197                 /* From an old provision it can happen that the tdb didn't exists yet */
 198                 DEBUG(0, ("Error while searching for the schema usn in the metadata\n"));
 199                 schema->metadata_usn = 0;
 200         }
 201         schema->last_refresh = ts;
 202
 203         ret = dsdb_module_load_partition_usn(module, schema_dn, &current_usn, NULL, NULL);
 204         if (ret != LDB_SUCCESS || current_usn == schema->loaded_usn) {
 205                 return schema;
 206         }
 207
 208         ret = dsdb_schema_from_db(module, schema_dn, current_usn, &new_schema);
 209         if (ret != LDB_SUCCESS) {
 210                 return schema;
 211         }
 212
 213         if (is_global_schema) {
 214                 dsdb_make_schema_global(ldb, new_schema);
 215         }
 216         return new_schema;
 217 }
 218
 219
 220 /*
 221   Given an LDB module (pointing at the schema DB), and the DN, set the populated schema
 222 */
 223
 224 static int dsdb_schema_from_db(struct ldb_module *module, struct ldb_dn *schema_dn, uint64_t current_usn,
 225                                struct dsdb_schema **schema)
 226 {
 227         struct ldb_context *ldb = ldb_module_get_ctx(module);
 228         TALLOC_CTX *tmp_ctx;
 229         char *error_string;
 230         int ret;
 231         struct ldb_result *schema_res;
 232         struct ldb_result *res;
 233         static const char *schema_attrs[] = {
 234                 "prefixMap",
 235                 "schemaInfo",
 236                 "fSMORoleOwner",
 237                 NULL
 238         };
 239         unsigned flags;
 240
 241         tmp_ctx = talloc_new(module);
 242         if (!tmp_ctx) {
 243                 return ldb_oom(ldb);
 244         }
 245
 246         /* we don't want to trace the schema load */
 247         flags = ldb_get_flags(ldb);
 248         ldb_set_flags(ldb, flags & ~LDB_FLG_ENABLE_TRACING);
 249
 250         /*
 251          * setup the prefix mappings and schema info
 252          */
 253         ret = dsdb_module_search_dn(module, tmp_ctx, &schema_res,
 254                                     schema_dn, schema_attrs,
 255                                     DSDB_FLAG_NEXT_MODULE, NULL);
 256         if (ret == LDB_ERR_NO_SUCH_OBJECT) {
 257                 ldb_reset_err_string(ldb);
 258                 ldb_debug(ldb, LDB_DEBUG_WARNING,
 259                           "schema_load_init: no schema head present: (skip schema loading)\n");
 260                 goto failed;
 261         } else if (ret != LDB_SUCCESS) {
 262                 ldb_asprintf_errstring(ldb,
 263                                        "dsdb_schema: failed to search the schema head: %s",
 264                                        ldb_errstring(ldb));
 265                 goto failed;
 266         }
 267
 268         /*
 269          * load the attribute definitions
 270          */
 271         ret = dsdb_module_search(module, tmp_ctx, &res,
 272                                  schema_dn, LDB_SCOPE_ONELEVEL, NULL,
 273                                  DSDB_FLAG_NEXT_MODULE |
 274                                  DSDB_SEARCH_SHOW_DN_IN_STORAGE_FORMAT,
 275                                  NULL,
 276                                  "(|(objectClass=attributeSchema)(objectClass=classSchema))");
 277         if (ret != LDB_SUCCESS) {
 278                 ldb_asprintf_errstring(ldb,
 279                                        "dsdb_schema: failed to search attributeSchema and classSchema objects: %s",
 280                                        ldb_errstring(ldb));
 281                 goto failed;
 282         }
 283
 284         ret = dsdb_schema_from_ldb_results(tmp_ctx, ldb,
 285                                            schema_res, res, schema, &error_string);
 286         if (ret != LDB_SUCCESS) {
 287                 ldb_asprintf_errstring(ldb,
 288                                        "dsdb_schema load failed: %s",
 289                                        error_string);
 290                 goto failed;
 291         }
 292
 293         (*schema)->refresh_in_progress = true;
 294
 295         /* If we have the readOnlySchema opaque, then don't check for
 296          * runtime schema updates, as they are not permitted (we would
 297          * have to update the backend server schema too */
 298         if (!ldb_get_opaque(ldb, "readOnlySchema")) {
 299                 (*schema)->refresh_fn = dsdb_schema_refresh;
 300                 (*schema)->loaded_from_module = module;
 301                 (*schema)->loaded_usn = current_usn;
 302         }
 303
 304         /* "dsdb_set_schema()" steals schema into the ldb_context */
 305         ret = dsdb_set_schema(ldb, (*schema));
 306
 307         (*schema)->refresh_in_progress = false;
 308         (*schema)->last_refresh = time(NULL);
 309
 310         if (ret != LDB_SUCCESS) {
 311                 ldb_debug_set(ldb, LDB_DEBUG_FATAL,
 312                               "schema_load_init: dsdb_set_schema() failed: %d:%s: %s",
 313                               ret, ldb_strerror(ret), ldb_errstring(ldb));
 314                 goto failed;
 315         }
 316
 317         /* Ensure this module won't go away before the callback.  This
 318          * causes every schema to have the LDB that originally loaded
 319          * the first schema as a talloc child. */
 320         if (talloc_reference(*schema, ldb) == NULL) {
 321                 ldb_oom(ldb);
 322                 ret = LDB_ERR_OPERATIONS_ERROR;
 323         }
 324
 325 failed:
 326         if (flags & LDB_FLG_ENABLE_TRACING) {
 327                 flags = ldb_get_flags(ldb);
 328                 ldb_set_flags(ldb, flags | LDB_FLG_ENABLE_TRACING);
 329         }
 330         talloc_free(tmp_ctx);
 331         return ret;
 332 }
 333
 334
 335 static int schema_load_init(struct ldb_module *module)
 336 {
 337         struct schema_load_private_data *private_data;
 338         struct dsdb_schema *schema;
 339         struct ldb_context *ldb = ldb_module_get_ctx(module);
 340         int ret;
 341         uint64_t current_usn;
 342         struct ldb_dn *schema_dn;
 343
 344         private_data = talloc_zero(module, struct schema_load_private_data);
 345         if (private_data == NULL) {
 346                 return ldb_oom(ldb);
 347         }
 348
 349         ldb_module_set_private(module, private_data);
 350
 351         ret = ldb_next_init(module);
 352         if (ret != LDB_SUCCESS) {
 353                 return ret;
 354         }
 355
 356         if (dsdb_get_schema(ldb, NULL)) {
 357                 return LDB_SUCCESS;
 358         }
 359
 360         schema_dn = ldb_get_schema_basedn(ldb);
 361         if (!schema_dn) {
 362                 ldb_reset_err_string(ldb);
 363                 ldb_debug(ldb, LDB_DEBUG_WARNING,
 364                           "schema_load_init: no schema dn present: (skip schema loading)\n");
 365                 return LDB_SUCCESS;
 366         }
 367
 368         ret = dsdb_module_load_partition_usn(module, schema_dn, &current_usn, NULL, NULL);
 369         if (ret != LDB_SUCCESS) {
 370                 /* Ignore the error and just reload the DB more often */
 371                 current_usn = 0;
 372         }
 373
 374         ret = dsdb_schema_from_db(module, schema_dn, current_usn, &schema);
 375         /* We don't care too much on the result of this action
 376          * the most probable reason for this to fail is that the tdb didn't
 377          * exists yet and this will be corrected by the partition module.
 378          */
 379         if (ret == LDB_SUCCESS && schema_metadata_open(module) == LDB_SUCCESS) {
 380                 uint64_t value;
 381
 382                 ret = schema_metadata_get_uint64(module, DSDB_METADATA_SCHEMA_SEQ_NUM, &value, 0);
 383                 if (ret == LDB_SUCCESS) {
 384                         schema->metadata_usn = value;
 385                 } else {
 386                         schema->metadata_usn = 0;
 387                 }
 388         }
 389         return ret;
 390 }
 391
 392 static int schema_search(struct ldb_module *module, struct ldb_request *req)
 393 {
 394         struct dsdb_schema *schema;
 395         struct ldb_context *ldb = ldb_module_get_ctx(module);
 396         uint64_t value;
 397         int ret;
 398         struct schema_load_private_data *private_data =
 399                 talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
 400
 401         schema = dsdb_get_schema(ldb, NULL);
 402         if (schema && private_data && !private_data->in_transaction) {
 403                 ret = schema_metadata_get_uint64(module, DSDB_METADATA_SCHEMA_SEQ_NUM, &value, 0);
 404                 if (ret == LDB_SUCCESS && schema->metadata_usn < value) {
 405                         /* The usn of the schema was changed in the metadata,
 406                         * this indicate that another process has modified the schema and
 407                         * that a reload is needed.
 408                         */
 409                         schema->last_refresh = 0;
 410                         schema = dsdb_get_schema(ldb, NULL);
 411                 }
 412         }
 413
 414         return ldb_next_request(module, req);
 415 }
 416
 417 static int schema_load_start_transaction(struct ldb_module *module)
 418 {
 419         struct schema_load_private_data *private_data =
 420                 talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
 421         struct dsdb_schema *schema;
 422         struct ldb_context *ldb = ldb_module_get_ctx(module);
 423         uint64_t value;
 424         int ret;
 425
 426         schema = dsdb_get_schema(ldb, NULL);
 427         if (!private_data->metadata) {
 428                 schema_metadata_open(module);
 429         }
 430         ret = schema_metadata_get_uint64(module, DSDB_METADATA_SCHEMA_SEQ_NUM, &value, 0);
 431         if (ret == LDB_SUCCESS && schema->metadata_usn < value) {
 432                 /* The usn of the schema was changed in the metadata,
 433                  * this indicate that another process has modified the schema and
 434                  * that a reload is needed.
 435                  */
 436                 schema->last_refresh = 0;
 437                 schema = dsdb_get_schema(ldb, NULL);
 438         }
 439         private_data->in_transaction = true;
 440
 441         return ldb_next_start_trans(module);
 442 }
 443
 444 static int schema_load_end_transaction(struct ldb_module *module)
 445 {
 446         struct schema_load_private_data *private_data =
 447                 talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
 448
 449         private_data->in_transaction = false;
 450
 451         return ldb_next_end_trans(module);
 452 }
 453
 454 static int schema_load_del_transaction(struct ldb_module *module)
 455 {
 456         struct schema_load_private_data *private_data =
 457                 talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
 458
 459         private_data->in_transaction = false;
 460
 461         return ldb_next_del_trans(module);
 462 }
 463
 464 static int schema_load_extended(struct ldb_module *module, struct ldb_request *req)
 465 {
 466         time_t *lastts;
 467         struct ldb_context *ldb = ldb_module_get_ctx(module);
 468         struct dsdb_schema *schema;
 469
 470         if (strcmp(req->op.extended.oid, DSDB_EXTENDED_SCHEMA_UPDATE_NOW_OID) != 0) {
 471                 return ldb_next_request(module, req);
 472         }
 473         lastts = (time_t *)ldb_get_opaque(ldb, DSDB_OPAQUE_LAST_SCHEMA_UPDATE_MSG_OPAQUE_NAME);
 474         if (!lastts) {
 475                 lastts = talloc(ldb, time_t);
 476         }
 477         schema = dsdb_get_schema(ldb, NULL);
 478         /* Force a refresh */
 479         schema->last_refresh = 0;
 480         *lastts = 0;
 481         ldb_set_opaque(ldb, DSDB_OPAQUE_LAST_SCHEMA_UPDATE_MSG_OPAQUE_NAME, lastts);
 482
 483         /* Pass to next module, the partition one should finish the chain */
 484         return ldb_next_request(module, req);
 485 }
 486
 487
 488 static const struct ldb_module_ops ldb_schema_load_module_ops = {
 489         .name           = "schema_load",
 490         .init_context   = schema_load_init,
 491         .extended       = schema_load_extended,
 492         .search         = schema_search,
 493         .start_transaction = schema_load_start_transaction,
 494         .end_transaction   = schema_load_end_transaction,
 495         .del_transaction   = schema_load_del_transaction,
 496 };
 497
 498 int ldb_schema_load_module_init(const char *version)
 499 {
 500         LDB_MODULE_CHECK_VERSION(version);
 501         return ldb_register_module(&ldb_schema_load_module_ops);
 502 }