lib/dbwrap/dbwrap.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Database interface wrapper
   4    Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2006
   5
   6    Major code contributions from Aleksey Fedoseev (fedoseev@ru.ibm.com)
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "dbwrap/dbwrap.h"
  24 #include "dbwrap/dbwrap_private.h"
  25 #include "lib/util/util_tdb.h"
  26
  27 /*
  28  * Fall back using fetch if no genuine exists operation is provided
  29  */
  30
  31 static int dbwrap_fallback_exists(struct db_context *db, TDB_DATA key)
  32 {
  33         NTSTATUS status = dbwrap_parse_record(db, key, NULL, NULL);
  34         return NT_STATUS_IS_OK(status) ? 1 : 0;
  35 }
  36
  37 static int delete_record(struct db_record *rec, void *data)
  38 {
  39         NTSTATUS status = dbwrap_record_delete(rec);
  40         return NT_STATUS_IS_OK(status) ? 0 : -1;
  41 }
  42
  43 /*
  44  * Fallback wipe implementation using traverse and delete if no genuine
  45  * wipe operation is provided
  46  */
  47 static int dbwrap_fallback_wipe(struct db_context *db)
  48 {
  49         NTSTATUS status = dbwrap_trans_traverse(db, delete_record, NULL);
  50         return NT_STATUS_IS_OK(status) ? 0 : -1;
  51 }
  52
  53 static int do_nothing(struct db_record *rec, void *unused)
  54 {
  55         return 0;
  56 }
  57
  58 /*
  59  * Fallback check operation: just traverse.
  60  */
  61 static int dbwrap_fallback_check(struct db_context *db)
  62 {
  63         NTSTATUS status = dbwrap_traverse_read(db, do_nothing, NULL, NULL);
  64         return NT_STATUS_IS_OK(status) ? 0 : -1;
  65 }
  66
  67 /*
  68  * Wrapper functions for the backend methods
  69  */
  70
  71 TDB_DATA dbwrap_record_get_key(const struct db_record *rec)
  72 {
  73         return rec->key;
  74 }
  75
  76 TDB_DATA dbwrap_record_get_value(const struct db_record *rec)
  77 {
  78         return rec->value;
  79 }
  80
  81 NTSTATUS dbwrap_record_store(struct db_record *rec, TDB_DATA data, int flags)
  82 {
  83         NTSTATUS status;
  84         struct db_context *db;
  85
  86         status = rec->store(rec, data, flags);
  87         if (!NT_STATUS_IS_OK(status)) {
  88                 return status;
  89         }
  90         db = rec->db;
  91         if (db->stored_callback != NULL) {
  92                 db->stored_callback(db, rec,
  93                                     db->stored_callback_private_data);
  94         }
  95         return NT_STATUS_OK;
  96 }
  97
  98 void dbwrap_set_stored_callback(
  99         struct db_context *db,
 100         void (*cb)(struct db_context *db, struct db_record *rec,
 101                    void *private_data),
 102         void *private_data)
 103 {
 104         db->stored_callback = cb;
 105         db->stored_callback_private_data = private_data;
 106 }
 107
 108 NTSTATUS dbwrap_record_delete(struct db_record *rec)
 109 {
 110         NTSTATUS status;
 111         struct db_context *db;
 112
 113         status = rec->delete_rec(rec);
 114         if (!NT_STATUS_IS_OK(status)) {
 115                 return status;
 116         }
 117         db = rec->db;
 118         if (db->stored_callback != NULL) {
 119                 db->stored_callback(db, rec,
 120                                     db->stored_callback_private_data);
 121         }
 122         return NT_STATUS_OK;
 123 }
 124
 125 struct dbwrap_lock_order_state {
 126         struct db_context **locked_dbs;
 127         struct db_context *db;
 128 };
 129
 130 static void debug_lock_order(int level, struct db_context *dbs[])
 131 {
 132         int i;
 133         DEBUG(level, ("lock order: "));
 134         for (i=0; i<DBWRAP_LOCK_ORDER_MAX; i++) {
 135                 DEBUGADD(level, (" %d:%s", i + 1, dbs[i] ? dbs[i]->name : "<none>"));
 136         }
 137         DEBUGADD(level, ("\n"));
 138 }
 139
 140 static int dbwrap_lock_order_state_destructor(
 141         struct dbwrap_lock_order_state *s)
 142 {
 143         int idx = s->db->lock_order - 1;
 144
 145         DEBUG(5, ("release lock order %d for %s\n",
 146                   (int)s->db->lock_order, s->db->name));
 147
 148         if (s->locked_dbs[idx] != s->db) {
 149                 DEBUG(0, ("locked db at lock order %d is %s, expected %s\n",
 150                           idx + 1, s->locked_dbs[idx]->name, s->db->name));
 151                 debug_lock_order(0, s->locked_dbs);
 152                 smb_panic("inconsistent lock_order\n");
 153         }
 154
 155         s->locked_dbs[idx] = NULL;
 156
 157         debug_lock_order(10, s->locked_dbs);
 158
 159         return 0;
 160 }
 161
 162
 163 static struct dbwrap_lock_order_state *dbwrap_check_lock_order(
 164         struct db_context *db, TALLOC_CTX *mem_ctx)
 165 {
 166         int idx;
 167         static struct db_context *locked_dbs[DBWRAP_LOCK_ORDER_MAX];
 168         struct dbwrap_lock_order_state *state = NULL;
 169
 170         if (db->lock_order > DBWRAP_LOCK_ORDER_MAX) {
 171                 DEBUG(0,("Invalid lock order %d of %s\n",
 172                          (int)db->lock_order, db->name));
 173                 smb_panic("invalid lock_order\n");
 174                 return NULL;
 175         }
 176
 177         DEBUG(5, ("check lock order %d for %s\n",
 178                   (int)db->lock_order, db->name));
 179
 180
 181         for (idx=db->lock_order - 1; idx < DBWRAP_LOCK_ORDER_MAX; idx++) {
 182                 if (locked_dbs[idx] != NULL) {
 183                         DEBUG(0, ("Lock order violation: Trying %s at %d while %s at %d is locked\n",
 184                                   db->name, (int)db->lock_order, locked_dbs[idx]->name, idx + 1));
 185                         debug_lock_order(0, locked_dbs);
 186                         smb_panic("invalid lock_order");
 187                         return NULL;
 188                 }
 189         }
 190
 191         state = talloc(mem_ctx, struct dbwrap_lock_order_state);
 192         if (state == NULL) {
 193                 DEBUG(1, ("talloc failed\n"));
 194                 return NULL;
 195         }
 196         state->db = db;
 197         state->locked_dbs = locked_dbs;
 198         talloc_set_destructor(state, dbwrap_lock_order_state_destructor);
 199
 200         locked_dbs[db->lock_order - 1] = db;
 201
 202         debug_lock_order(10, locked_dbs);
 203
 204         return state;
 205 }
 206
 207 static struct db_record *dbwrap_fetch_locked_internal(
 208         struct db_context *db, TALLOC_CTX *mem_ctx, TDB_DATA key,
 209         struct db_record *(*db_fn)(struct db_context *db, TALLOC_CTX *mem_ctx,
 210                                    TDB_DATA key))
 211 {
 212         struct db_record *rec;
 213         struct dbwrap_lock_order_state *lock_order = NULL;
 214
 215         if (db->lock_order != 0) {
 216                 lock_order = dbwrap_check_lock_order(db, mem_ctx);
 217                 if (lock_order == NULL) {
 218                         return NULL;
 219                 }
 220         }
 221         rec = db_fn(db, mem_ctx, key);
 222         if (rec == NULL) {
 223                 TALLOC_FREE(lock_order);
 224                 return NULL;
 225         }
 226         (void)talloc_steal(rec, lock_order);
 227         rec->db = db;
 228         return rec;
 229 }
 230
 231 struct db_record *dbwrap_fetch_locked(struct db_context *db,
 232                                       TALLOC_CTX *mem_ctx,
 233                                       TDB_DATA key)
 234 {
 235         return dbwrap_fetch_locked_internal(db, mem_ctx, key,
 236                                             db->fetch_locked);
 237 }
 238
 239 struct db_record *dbwrap_try_fetch_locked(struct db_context *db,
 240                                       TALLOC_CTX *mem_ctx,
 241                                       TDB_DATA key)
 242 {
 243         return dbwrap_fetch_locked_internal(
 244                 db, mem_ctx, key,
 245                 db->try_fetch_locked
 246                 ? db->try_fetch_locked : db->fetch_locked);
 247 }
 248
 249 struct db_context *dbwrap_record_get_db(struct db_record *rec)
 250 {
 251         return rec->db;
 252 }
 253
 254 struct dbwrap_fetch_state {
 255         TALLOC_CTX *mem_ctx;
 256         TDB_DATA data;
 257 };
 258
 259 static void dbwrap_fetch_parser(TDB_DATA key, TDB_DATA data,
 260                                 void *private_data)
 261 {
 262         struct dbwrap_fetch_state *state =
 263                 (struct dbwrap_fetch_state *)private_data;
 264
 265         state->data.dsize = data.dsize;
 266         state->data.dptr = (uint8_t *)talloc_memdup(state->mem_ctx, data.dptr,
 267                                                     data.dsize);
 268 }
 269
 270 NTSTATUS dbwrap_fetch(struct db_context *db, TALLOC_CTX *mem_ctx,
 271                       TDB_DATA key, TDB_DATA *value)
 272 {
 273         struct dbwrap_fetch_state state;
 274         NTSTATUS status;
 275
 276         if (value == NULL) {
 277                 return NT_STATUS_INVALID_PARAMETER;
 278         }
 279
 280         state.mem_ctx = mem_ctx;
 281
 282         status = dbwrap_parse_record(db, key, dbwrap_fetch_parser, &state);
 283         if (!NT_STATUS_IS_OK(status)) {
 284                 return status;
 285         }
 286         if ((state.data.dsize != 0) && (state.data.dptr == NULL)) {
 287                 return NT_STATUS_NO_MEMORY;
 288         }
 289         *value = state.data;
 290         return NT_STATUS_OK;
 291 }
 292
 293 bool dbwrap_exists(struct db_context *db, TDB_DATA key)
 294 {
 295         int result;
 296         if (db->exists != NULL) {
 297                 result = db->exists(db, key);
 298         } else {
 299                 result = dbwrap_fallback_exists(db,key);
 300         }
 301         return (result == 1);
 302 }
 303
 304 NTSTATUS dbwrap_store(struct db_context *db, TDB_DATA key,
 305                       TDB_DATA data, int flags)
 306 {
 307         struct db_record *rec;
 308         NTSTATUS status;
 309         TALLOC_CTX *frame = talloc_stackframe();
 310
 311         rec = dbwrap_fetch_locked(db, frame, key);
 312         if (rec == NULL) {
 313                 TALLOC_FREE(frame);
 314                 return NT_STATUS_NO_MEMORY;
 315         }
 316
 317         status = dbwrap_record_store(rec, data, flags);
 318         TALLOC_FREE(frame);
 319         return status;
 320 }
 321
 322 NTSTATUS dbwrap_delete(struct db_context *db, TDB_DATA key)
 323 {
 324         struct db_record *rec;
 325         NTSTATUS status;
 326         TALLOC_CTX *frame = talloc_stackframe();
 327
 328         rec = dbwrap_fetch_locked(db, frame, key);
 329         if (rec == NULL) {
 330                 TALLOC_FREE(frame);
 331                 return NT_STATUS_NO_MEMORY;
 332         }
 333         status = dbwrap_record_delete(rec);
 334         TALLOC_FREE(frame);
 335         return status;
 336 }
 337
 338 NTSTATUS dbwrap_traverse(struct db_context *db,
 339                          int (*f)(struct db_record*, void*),
 340                          void *private_data,
 341                          int *count)
 342 {
 343         int ret = db->traverse(db, f, private_data);
 344
 345         if (ret < 0) {
 346                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 347         }
 348
 349         if (count != NULL) {
 350                 *count = ret;
 351         }
 352
 353         return NT_STATUS_OK;
 354 }
 355
 356 NTSTATUS dbwrap_traverse_read(struct db_context *db,
 357                               int (*f)(struct db_record*, void*),
 358                               void *private_data,
 359                               int *count)
 360 {
 361         int ret = db->traverse_read(db, f, private_data);
 362
 363         if (ret < 0) {
 364                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 365         }
 366
 367         if (count != NULL) {
 368                 *count = ret;
 369         }
 370
 371         return NT_STATUS_OK;
 372 }
 373
 374 static void dbwrap_null_parser(TDB_DATA key, TDB_DATA val, void* data)
 375 {
 376         return;
 377 }
 378
 379 NTSTATUS dbwrap_parse_record(struct db_context *db, TDB_DATA key,
 380                              void (*parser)(TDB_DATA key, TDB_DATA data,
 381                                             void *private_data),
 382                              void *private_data)
 383 {
 384         if (parser == NULL) {
 385                 parser = dbwrap_null_parser;
 386         }
 387         return db->parse_record(db, key, parser, private_data);
 388 }
 389
 390 int dbwrap_wipe(struct db_context *db)
 391 {
 392         if (db->wipe == NULL) {
 393                 return dbwrap_fallback_wipe(db);
 394         }
 395         return db->wipe(db);
 396 }
 397
 398 int dbwrap_hash_size(struct db_context *db)
 399 {
 400         return db->hash_size;
 401 }
 402
 403 int dbwrap_check(struct db_context *db)
 404 {
 405         if (db->check == NULL) {
 406                 return dbwrap_fallback_check(db);
 407         }
 408         return db->check(db);
 409 }
 410
 411 int dbwrap_get_seqnum(struct db_context *db)
 412 {
 413         return db->get_seqnum(db);
 414 }
 415
 416 int dbwrap_transaction_start(struct db_context *db)
 417 {
 418         if (!db->persistent) {
 419                 /*
 420                  * dbwrap_ctdb has two different data models for persistent
 421                  * and non-persistent databases. Transactions are supported
 422                  * only for the persistent databases. This check is here to
 423                  * prevent breakages of the cluster case, autobuild at this
 424                  * point only tests non-clustered Samba. Before removing this
 425                  * check, please make sure that this facility has also been
 426                  * added to dbwrap_ctdb.
 427                  *
 428                  * Thanks, vl
 429                  */
 430                 DEBUG(1, ("transactions not supported on non-persistent "
 431                           "database %s\n", db->name));
 432                 return -1;
 433         }
 434         return db->transaction_start(db);
 435 }
 436
 437 NTSTATUS dbwrap_transaction_start_nonblock(struct db_context *db)
 438 {
 439         if (db->transaction_start_nonblock) {
 440                 return db->transaction_start_nonblock(db);
 441         } else {
 442                 return dbwrap_transaction_start(db) == 0 ? NT_STATUS_OK
 443                         : NT_STATUS_UNSUCCESSFUL;
 444         }
 445 }
 446
 447 int dbwrap_transaction_commit(struct db_context *db)
 448 {
 449         return db->transaction_commit(db);
 450 }
 451
 452 int dbwrap_transaction_cancel(struct db_context *db)
 453 {
 454         return db->transaction_cancel(db);
 455 }
 456
 457 void dbwrap_db_id(struct db_context *db, const uint8_t **id, size_t *idlen)
 458 {
 459         db->id(db, id, idlen);
 460 }
 461
 462 bool dbwrap_is_persistent(struct db_context *db)
 463 {
 464         return db->persistent;
 465 }
 466
 467 const char *dbwrap_name(struct db_context *db)
 468 {
 469         return db->name;
 470 }