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 == 0) {
 171                 /*
 172                  * lock order 0 is for example for dbwrap_rbt without
 173                  * real locking. Return state nevertheless to avoid
 174                  * special cases.
 175                  */
 176                 return talloc_zero(mem_ctx, struct dbwrap_lock_order_state);
 177         }
 178
 179         if (db->lock_order > DBWRAP_LOCK_ORDER_MAX) {
 180                 DEBUG(0,("Invalid lock order %d of %s\n",
 181                          (int)db->lock_order, db->name));
 182                 smb_panic("invalid lock_order\n");
 183                 return NULL;
 184         }
 185
 186         DEBUG(5, ("check lock order %d for %s\n",
 187                   (int)db->lock_order, db->name));
 188
 189
 190         for (idx=db->lock_order - 1; idx < DBWRAP_LOCK_ORDER_MAX; idx++) {
 191                 if (locked_dbs[idx] != NULL) {
 192                         DEBUG(0, ("Lock order violation: Trying %s at %d while %s at %d is locked\n",
 193                                   db->name, (int)db->lock_order, locked_dbs[idx]->name, idx + 1));
 194                         debug_lock_order(0, locked_dbs);
 195                         smb_panic("invalid lock_order");
 196                         return NULL;
 197                 }
 198         }
 199
 200         state = talloc(mem_ctx, struct dbwrap_lock_order_state);
 201         if (state == NULL) {
 202                 DEBUG(1, ("talloc failed\n"));
 203                 return NULL;
 204         }
 205         state->db = db;
 206         state->locked_dbs = locked_dbs;
 207         talloc_set_destructor(state, dbwrap_lock_order_state_destructor);
 208
 209         locked_dbs[db->lock_order - 1] = db;
 210
 211         debug_lock_order(10, locked_dbs);
 212
 213         return state;
 214 }
 215
 216 static struct db_record *dbwrap_fetch_locked_internal(
 217         struct db_context *db, TALLOC_CTX *mem_ctx, TDB_DATA key,
 218         struct db_record *(*db_fn)(struct db_context *db, TALLOC_CTX *mem_ctx,
 219                                    TDB_DATA key))
 220 {
 221         struct db_record *rec;
 222         struct dbwrap_lock_order_state *lock_order;
 223         TALLOC_CTX *frame = talloc_stackframe();
 224
 225         lock_order = dbwrap_check_lock_order(db, frame);
 226         if (lock_order == NULL) {
 227                 TALLOC_FREE(frame);
 228                 return NULL;
 229         }
 230         rec = db_fn(db, mem_ctx, key);
 231         if (rec == NULL) {
 232                 TALLOC_FREE(frame);
 233                 return NULL;
 234         }
 235         (void)talloc_steal(rec, lock_order);
 236         rec->db = db;
 237         TALLOC_FREE(frame);
 238         return rec;
 239 }
 240
 241 struct db_record *dbwrap_fetch_locked(struct db_context *db,
 242                                       TALLOC_CTX *mem_ctx,
 243                                       TDB_DATA key)
 244 {
 245         return dbwrap_fetch_locked_internal(db, mem_ctx, key,
 246                                             db->fetch_locked);
 247 }
 248
 249 struct db_record *dbwrap_try_fetch_locked(struct db_context *db,
 250                                       TALLOC_CTX *mem_ctx,
 251                                       TDB_DATA key)
 252 {
 253         return dbwrap_fetch_locked_internal(
 254                 db, mem_ctx, key,
 255                 db->try_fetch_locked
 256                 ? db->try_fetch_locked : db->fetch_locked);
 257 }
 258
 259 struct db_context *dbwrap_record_get_db(struct db_record *rec)
 260 {
 261         return rec->db;
 262 }
 263
 264 struct dbwrap_fetch_state {
 265         TALLOC_CTX *mem_ctx;
 266         TDB_DATA data;
 267 };
 268
 269 static void dbwrap_fetch_parser(TDB_DATA key, TDB_DATA data,
 270                                 void *private_data)
 271 {
 272         struct dbwrap_fetch_state *state =
 273                 (struct dbwrap_fetch_state *)private_data;
 274
 275         state->data.dsize = data.dsize;
 276         state->data.dptr = (uint8_t *)talloc_memdup(state->mem_ctx, data.dptr,
 277                                                     data.dsize);
 278 }
 279
 280 NTSTATUS dbwrap_fetch(struct db_context *db, TALLOC_CTX *mem_ctx,
 281                       TDB_DATA key, TDB_DATA *value)
 282 {
 283         struct dbwrap_fetch_state state;
 284         NTSTATUS status;
 285
 286         if (value == NULL) {
 287                 return NT_STATUS_INVALID_PARAMETER;
 288         }
 289
 290         state.mem_ctx = mem_ctx;
 291
 292         status = dbwrap_parse_record(db, key, dbwrap_fetch_parser, &state);
 293         if (!NT_STATUS_IS_OK(status)) {
 294                 return status;
 295         }
 296         if ((state.data.dsize != 0) && (state.data.dptr == NULL)) {
 297                 return NT_STATUS_NO_MEMORY;
 298         }
 299         *value = state.data;
 300         return NT_STATUS_OK;
 301 }
 302
 303 bool dbwrap_exists(struct db_context *db, TDB_DATA key)
 304 {
 305         int result;
 306         if (db->exists != NULL) {
 307                 result = db->exists(db, key);
 308         } else {
 309                 result = dbwrap_fallback_exists(db,key);
 310         }
 311         return (result == 1);
 312 }
 313
 314 NTSTATUS dbwrap_store(struct db_context *db, TDB_DATA key,
 315                       TDB_DATA data, int flags)
 316 {
 317         struct db_record *rec;
 318         NTSTATUS status;
 319         TALLOC_CTX *frame = talloc_stackframe();
 320
 321         rec = dbwrap_fetch_locked(db, frame, key);
 322         if (rec == NULL) {
 323                 TALLOC_FREE(frame);
 324                 return NT_STATUS_NO_MEMORY;
 325         }
 326
 327         status = dbwrap_record_store(rec, data, flags);
 328         TALLOC_FREE(frame);
 329         return status;
 330 }
 331
 332 NTSTATUS dbwrap_delete(struct db_context *db, TDB_DATA key)
 333 {
 334         struct db_record *rec;
 335         NTSTATUS status;
 336         TALLOC_CTX *frame = talloc_stackframe();
 337
 338         rec = dbwrap_fetch_locked(db, frame, key);
 339         if (rec == NULL) {
 340                 TALLOC_FREE(frame);
 341                 return NT_STATUS_NO_MEMORY;
 342         }
 343         status = dbwrap_record_delete(rec);
 344         TALLOC_FREE(frame);
 345         return status;
 346 }
 347
 348 NTSTATUS dbwrap_traverse(struct db_context *db,
 349                          int (*f)(struct db_record*, void*),
 350                          void *private_data,
 351                          int *count)
 352 {
 353         int ret = db->traverse(db, f, private_data);
 354
 355         if (ret < 0) {
 356                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 357         }
 358
 359         if (count != NULL) {
 360                 *count = ret;
 361         }
 362
 363         return NT_STATUS_OK;
 364 }
 365
 366 NTSTATUS dbwrap_traverse_read(struct db_context *db,
 367                               int (*f)(struct db_record*, void*),
 368                               void *private_data,
 369                               int *count)
 370 {
 371         int ret = db->traverse_read(db, f, private_data);
 372
 373         if (ret < 0) {
 374                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 375         }
 376
 377         if (count != NULL) {
 378                 *count = ret;
 379         }
 380
 381         return NT_STATUS_OK;
 382 }
 383
 384 static void dbwrap_null_parser(TDB_DATA key, TDB_DATA val, void* data)
 385 {
 386         return;
 387 }
 388
 389 NTSTATUS dbwrap_parse_record(struct db_context *db, TDB_DATA key,
 390                              void (*parser)(TDB_DATA key, TDB_DATA data,
 391                                             void *private_data),
 392                              void *private_data)
 393 {
 394         if (parser == NULL) {
 395                 parser = dbwrap_null_parser;
 396         }
 397         return db->parse_record(db, key, parser, private_data);
 398 }
 399
 400 int dbwrap_wipe(struct db_context *db)
 401 {
 402         if (db->wipe == NULL) {
 403                 return dbwrap_fallback_wipe(db);
 404         }
 405         return db->wipe(db);
 406 }
 407
 408 int dbwrap_hash_size(struct db_context *db)
 409 {
 410         return db->hash_size;
 411 }
 412
 413 int dbwrap_check(struct db_context *db)
 414 {
 415         if (db->check == NULL) {
 416                 return dbwrap_fallback_check(db);
 417         }
 418         return db->check(db);
 419 }
 420
 421 int dbwrap_get_seqnum(struct db_context *db)
 422 {
 423         return db->get_seqnum(db);
 424 }
 425
 426 int dbwrap_transaction_start(struct db_context *db)
 427 {
 428         if (!db->persistent) {
 429                 /*
 430                  * dbwrap_ctdb has two different data models for persistent
 431                  * and non-persistent databases. Transactions are supported
 432                  * only for the persistent databases. This check is here to
 433                  * prevent breakages of the cluster case, autobuild at this
 434                  * point only tests non-clustered Samba. Before removing this
 435                  * check, please make sure that this facility has also been
 436                  * added to dbwrap_ctdb.
 437                  *
 438                  * Thanks, vl
 439                  */
 440                 DEBUG(1, ("transactions not supported on non-persistent "
 441                           "database %s\n", db->name));
 442                 return -1;
 443         }
 444         return db->transaction_start(db);
 445 }
 446
 447 NTSTATUS dbwrap_transaction_start_nonblock(struct db_context *db)
 448 {
 449         if (db->transaction_start_nonblock) {
 450                 return db->transaction_start_nonblock(db);
 451         } else {
 452                 return dbwrap_transaction_start(db) == 0 ? NT_STATUS_OK
 453                         : NT_STATUS_UNSUCCESSFUL;
 454         }
 455 }
 456
 457 int dbwrap_transaction_commit(struct db_context *db)
 458 {
 459         return db->transaction_commit(db);
 460 }
 461
 462 int dbwrap_transaction_cancel(struct db_context *db)
 463 {
 464         return db->transaction_cancel(db);
 465 }
 466
 467 void dbwrap_db_id(struct db_context *db, const uint8_t **id, size_t *idlen)
 468 {
 469         db->id(db, id, idlen);
 470 }
 471
 472 bool dbwrap_is_persistent(struct db_context *db)
 473 {
 474         return db->persistent;
 475 }
 476
 477 const char *dbwrap_name(struct db_context *db)
 478 {
 479         return db->name;
 480 }