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