source3/lib/g_lock.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    global locks based on dbwrap and messaging
   4    Copyright (C) 2009 by Volker Lendecke
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "system/filesys.h"
  22 #include "lib/util/server_id.h"
  23 #include "dbwrap/dbwrap.h"
  24 #include "dbwrap/dbwrap_open.h"
  25 #include "dbwrap/dbwrap_watch.h"
  26 #include "g_lock.h"
  27 #include "util_tdb.h"
  28 #include "../lib/util/tevent_ntstatus.h"
  29 #include "messages.h"
  30 #include "serverid.h"
  31
  32 struct g_lock_ctx {
  33         struct db_context *db;
  34         struct messaging_context *msg;
  35 };
  36
  37 /*
  38  * The "g_lock.tdb" file contains records, indexed by the 0-terminated
  39  * lockname. The record contains an array of "struct g_lock_rec"
  40  * structures.
  41  */
  42
  43 #define G_LOCK_REC_LENGTH (SERVER_ID_BUF_LENGTH+1)
  44
  45 static void g_lock_rec_put(uint8_t buf[G_LOCK_REC_LENGTH],
  46                            const struct g_lock_rec rec)
  47 {
  48         SCVAL(buf, 0, rec.lock_type);
  49         server_id_put(buf+1, rec.pid);
  50 }
  51
  52 static void g_lock_rec_get(struct g_lock_rec *rec,
  53                            const uint8_t buf[G_LOCK_REC_LENGTH])
  54 {
  55         rec->lock_type = CVAL(buf, 0);
  56         server_id_get(&rec->pid, buf+1);
  57 }
  58
  59 static ssize_t g_lock_put(uint8_t *buf, size_t buflen,
  60                           const struct g_lock_rec *locks,
  61                           size_t num_locks,
  62                           const uint8_t *data, size_t datalen)
  63 {
  64         size_t i, len, ofs;
  65
  66         if (num_locks > UINT32_MAX/G_LOCK_REC_LENGTH) {
  67                 return -1;
  68         }
  69
  70         len = num_locks * G_LOCK_REC_LENGTH;
  71
  72         len += sizeof(uint32_t);
  73         if (len < sizeof(uint32_t)) {
  74                 return -1;
  75         }
  76
  77         len += datalen;
  78         if (len < datalen) {
  79                 return -1;
  80         }
  81
  82         if (len > buflen) {
  83                 return len;
  84         }
  85
  86         ofs = 0;
  87         SIVAL(buf, ofs, num_locks);
  88         ofs += sizeof(uint32_t);
  89
  90         for (i=0; i<num_locks; i++) {
  91                 g_lock_rec_put(buf+ofs, locks[i]);
  92                 ofs += G_LOCK_REC_LENGTH;
  93         }
  94
  95         if ((data != NULL) && (datalen != 0)) {
  96                 memcpy(buf+ofs, data, datalen);
  97         }
  98
  99         return len;
 100 }
 101
 102 static ssize_t g_lock_get(TDB_DATA recval,
 103                           struct g_lock_rec *locks, size_t num_locks,
 104                           uint8_t **data, size_t *datalen)
 105 {
 106         size_t found_locks;
 107
 108         if (recval.dsize < sizeof(uint32_t)) {
 109                 /* Fresh or invalid record */
 110                 found_locks = 0;
 111                 goto done;
 112         }
 113
 114         found_locks = IVAL(recval.dptr, 0);
 115         recval.dptr += sizeof(uint32_t);
 116         recval.dsize -= sizeof(uint32_t);
 117
 118         if (found_locks > recval.dsize/G_LOCK_REC_LENGTH) {
 119                 /* Invalid record */
 120                 return 0;
 121         }
 122
 123         if (found_locks <= num_locks) {
 124                 size_t i;
 125
 126                 for (i=0; i<found_locks; i++) {
 127                         g_lock_rec_get(&locks[i], recval.dptr);
 128                         recval.dptr += G_LOCK_REC_LENGTH;
 129                         recval.dsize -= G_LOCK_REC_LENGTH;
 130                 }
 131         } else {
 132                 /*
 133                  * Not enough space passed in by the caller, don't
 134                  * parse the locks.
 135                  */
 136                 recval.dptr += found_locks * G_LOCK_REC_LENGTH;
 137                 recval.dsize -= found_locks * G_LOCK_REC_LENGTH;
 138         }
 139
 140 done:
 141         if (data != NULL) {
 142                 *data = recval.dptr;
 143         }
 144         if (datalen != NULL) {
 145                 *datalen = recval.dsize;
 146         }
 147         return found_locks;
 148 }
 149
 150 static NTSTATUS g_lock_get_talloc(TALLOC_CTX *mem_ctx, TDB_DATA recval,
 151                                   struct g_lock_rec **plocks,
 152                                   size_t *pnum_locks,
 153                                   uint8_t **data, size_t *datalen)
 154 {
 155         struct g_lock_rec *locks;
 156         ssize_t num_locks;
 157
 158         num_locks = g_lock_get(recval, NULL, 0, NULL, NULL);
 159         if (num_locks == -1) {
 160                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 161         }
 162         locks = talloc_array(mem_ctx, struct g_lock_rec, num_locks);
 163         if (locks == NULL) {
 164                 return NT_STATUS_NO_MEMORY;
 165         }
 166         g_lock_get(recval, locks, num_locks, data, datalen);
 167
 168         *plocks = locks;
 169         *pnum_locks = num_locks;
 170
 171         return NT_STATUS_OK;
 172 }
 173
 174 struct g_lock_ctx *g_lock_ctx_init(TALLOC_CTX *mem_ctx,
 175                                    struct messaging_context *msg)
 176 {
 177         struct g_lock_ctx *result;
 178         struct db_context *backend;
 179         char *db_path;
 180
 181         result = talloc(mem_ctx, struct g_lock_ctx);
 182         if (result == NULL) {
 183                 return NULL;
 184         }
 185         result->msg = msg;
 186
 187         db_path = lock_path("g_lock.tdb");
 188         if (db_path == NULL) {
 189                 TALLOC_FREE(result);
 190                 return NULL;
 191         }
 192
 193         backend = db_open(result, db_path, 0,
 194                           TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH,
 195                           O_RDWR|O_CREAT, 0600,
 196                           DBWRAP_LOCK_ORDER_2,
 197                           DBWRAP_FLAG_NONE);
 198         TALLOC_FREE(db_path);
 199         if (backend == NULL) {
 200                 DEBUG(1, ("g_lock_init: Could not open g_lock.tdb\n"));
 201                 TALLOC_FREE(result);
 202                 return NULL;
 203         }
 204
 205         result->db = db_open_watched(result, backend, msg);
 206         if (result->db == NULL) {
 207                 DBG_WARNING("g_lock_init: db_open_watched failed\n");
 208                 TALLOC_FREE(result);
 209                 return NULL;
 210         }
 211         return result;
 212 }
 213
 214 static bool g_lock_conflicts(enum g_lock_type l1, enum g_lock_type l2)
 215 {
 216         /*
 217          * Only tested write locks so far. Very likely this routine
 218          * needs to be fixed for read locks....
 219          */
 220         if ((l1 == G_LOCK_READ) && (l2 == G_LOCK_READ)) {
 221                 return false;
 222         }
 223         return true;
 224 }
 225
 226 static NTSTATUS g_lock_record_store(struct db_record *rec,
 227                                     const struct g_lock_rec *locks,
 228                                     size_t num_locks,
 229                                     const uint8_t *data, size_t datalen)
 230 {
 231         ssize_t len;
 232         uint8_t *buf;
 233         NTSTATUS status;
 234
 235         len = g_lock_put(NULL, 0, locks, num_locks, data, datalen);
 236         if (len == -1) {
 237                 return NT_STATUS_BUFFER_TOO_SMALL;
 238         }
 239
 240         buf = talloc_array(rec, uint8_t, len);
 241         if (buf == NULL) {
 242                 return NT_STATUS_NO_MEMORY;
 243         }
 244
 245         g_lock_put(buf, len, locks, num_locks, data, datalen);
 246
 247         status = dbwrap_record_store(
 248                 rec, (TDB_DATA) { .dptr = buf, .dsize = len }, 0);
 249
 250         TALLOC_FREE(buf);
 251
 252         return status;
 253 }
 254
 255 static NTSTATUS g_lock_trylock(struct db_record *rec, struct server_id self,
 256                                enum g_lock_type type,
 257                                struct server_id *blocker)
 258 {
 259         TDB_DATA data, userdata;
 260         size_t i, num_locks;
 261         struct g_lock_rec *locks, *tmp;
 262         NTSTATUS status;
 263         bool modified = false;
 264
 265         data = dbwrap_record_get_value(rec);
 266
 267         status = g_lock_get_talloc(talloc_tos(), data, &locks, &num_locks,
 268                                    &userdata.dptr, &userdata.dsize);
 269         if (!NT_STATUS_IS_OK(status)) {
 270                 return status;
 271         }
 272
 273         for (i=0; i<num_locks; i++) {
 274                 if (serverid_equal(&self, &locks[i].pid)) {
 275                         status = NT_STATUS_INTERNAL_ERROR;
 276                         goto done;
 277                 }
 278                 if (g_lock_conflicts(type, locks[i].lock_type)) {
 279                         struct server_id pid = locks[i].pid;
 280
 281                         /*
 282                          * As the serverid_exists might recurse into
 283                          * the g_lock code, we use
 284                          * SERVERID_UNIQUE_ID_NOT_TO_VERIFY to avoid the loop
 285                          */
 286                         pid.unique_id = SERVERID_UNIQUE_ID_NOT_TO_VERIFY;
 287
 288                         if (serverid_exists(&pid)) {
 289                                 status = NT_STATUS_LOCK_NOT_GRANTED;
 290                                 *blocker = locks[i].pid;
 291                                 goto done;
 292                         }
 293
 294                         /*
 295                          * Delete stale conflicting entry
 296                          */
 297                         locks[i] = locks[num_locks-1];
 298                         num_locks -= 1;
 299                         modified = true;
 300                 }
 301         }
 302
 303         tmp = talloc_realloc(talloc_tos(), locks, struct g_lock_rec,
 304                              num_locks+1);
 305         if (tmp == NULL) {
 306                 status = NT_STATUS_NO_MEMORY;
 307                 goto done;
 308         }
 309         locks = tmp;
 310
 311         ZERO_STRUCT(locks[num_locks]);
 312         locks[num_locks].pid = self;
 313         locks[num_locks].lock_type = type;
 314         num_locks += 1;
 315         modified = true;
 316
 317         status = NT_STATUS_OK;
 318 done:
 319         if (modified) {
 320                 NTSTATUS store_status;
 321                 store_status = g_lock_record_store(
 322                         rec, locks, num_locks, userdata.dptr, userdata.dsize);
 323                 if (!NT_STATUS_IS_OK(store_status)) {
 324                         DBG_WARNING("g_lock_record_store failed: %s\n",
 325                                     nt_errstr(store_status));
 326                         status = store_status;
 327                 }
 328         }
 329         TALLOC_FREE(locks);
 330         return status;
 331 }
 332
 333 struct g_lock_lock_state {
 334         struct tevent_context *ev;
 335         struct g_lock_ctx *ctx;
 336         const char *name;
 337         enum g_lock_type type;
 338 };
 339
 340 static void g_lock_lock_retry(struct tevent_req *subreq);
 341
 342 struct tevent_req *g_lock_lock_send(TALLOC_CTX *mem_ctx,
 343                                     struct tevent_context *ev,
 344                                     struct g_lock_ctx *ctx,
 345                                     const char *name,
 346                                     enum g_lock_type type)
 347 {
 348         struct tevent_req *req, *subreq;
 349         struct g_lock_lock_state *state;
 350         struct db_record *rec;
 351         struct server_id self, blocker;
 352         NTSTATUS status;
 353
 354         req = tevent_req_create(mem_ctx, &state, struct g_lock_lock_state);
 355         if (req == NULL) {
 356                 return NULL;
 357         }
 358         state->ev = ev;
 359         state->ctx = ctx;
 360         state->name = name;
 361         state->type = type;
 362
 363         rec = dbwrap_fetch_locked(ctx->db, talloc_tos(),
 364                                   string_term_tdb_data(state->name));
 365         if (rec == NULL) {
 366                 DEBUG(10, ("fetch_locked(\"%s\") failed\n", name));
 367                 tevent_req_nterror(req, NT_STATUS_LOCK_NOT_GRANTED);
 368                 return tevent_req_post(req, ev);
 369         }
 370
 371         self = messaging_server_id(state->ctx->msg);
 372
 373         status = g_lock_trylock(rec, self, state->type, &blocker);
 374         if (NT_STATUS_IS_OK(status)) {
 375                 TALLOC_FREE(rec);
 376                 tevent_req_done(req);
 377                 return tevent_req_post(req, ev);
 378         }
 379         if (!NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) {
 380                 TALLOC_FREE(rec);
 381                 tevent_req_nterror(req, status);
 382                 return tevent_req_post(req, ev);
 383         }
 384         subreq = dbwrap_watched_watch_send(state, state->ev, rec, blocker);
 385         TALLOC_FREE(rec);
 386         if (tevent_req_nomem(subreq, req)) {
 387                 return tevent_req_post(req, ev);
 388         }
 389         if (!tevent_req_set_endtime(
 390                     subreq, state->ev,
 391                     timeval_current_ofs(5 + sys_random() % 5, 0))) {
 392                 tevent_req_oom(req);
 393                 return tevent_req_post(req, ev);
 394         }
 395         tevent_req_set_callback(subreq, g_lock_lock_retry, req);
 396         return req;
 397 }
 398
 399 static void g_lock_lock_retry(struct tevent_req *subreq)
 400 {
 401         struct tevent_req *req = tevent_req_callback_data(
 402                 subreq, struct tevent_req);
 403         struct g_lock_lock_state *state = tevent_req_data(
 404                 req, struct g_lock_lock_state);
 405         struct server_id self = messaging_server_id(state->ctx->msg);
 406         struct server_id blocker;
 407         struct db_record *rec;
 408         NTSTATUS status;
 409
 410         status = dbwrap_watched_watch_recv(subreq, talloc_tos(), &rec, NULL,
 411                                            NULL);
 412         TALLOC_FREE(subreq);
 413
 414         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT)) {
 415                 rec = dbwrap_fetch_locked(
 416                         state->ctx->db, talloc_tos(),
 417                         string_term_tdb_data(state->name));
 418                 if (rec == NULL) {
 419                         status = map_nt_error_from_unix(errno);
 420                 } else {
 421                         status = NT_STATUS_OK;
 422                 }
 423         }
 424
 425         if (tevent_req_nterror(req, status)) {
 426                 return;
 427         }
 428         status = g_lock_trylock(rec, self, state->type, &blocker);
 429         if (NT_STATUS_IS_OK(status)) {
 430                 TALLOC_FREE(rec);
 431                 tevent_req_done(req);
 432                 return;
 433         }
 434         if (!NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) {
 435                 TALLOC_FREE(rec);
 436                 tevent_req_nterror(req, status);
 437                 return;
 438         }
 439         subreq = dbwrap_watched_watch_send(state, state->ev, rec, blocker);
 440         TALLOC_FREE(rec);
 441         if (tevent_req_nomem(subreq, req)) {
 442                 return;
 443         }
 444         if (!tevent_req_set_endtime(
 445                     subreq, state->ev,
 446                     timeval_current_ofs(5 + sys_random() % 5, 0))) {
 447                 tevent_req_oom(req);
 448                 return;
 449         }
 450         tevent_req_set_callback(subreq, g_lock_lock_retry, req);
 451         return;
 452
 453 }
 454
 455 NTSTATUS g_lock_lock_recv(struct tevent_req *req)
 456 {
 457         return tevent_req_simple_recv_ntstatus(req);
 458 }
 459
 460 NTSTATUS g_lock_lock(struct g_lock_ctx *ctx, const char *name,
 461                      enum g_lock_type type, struct timeval timeout)
 462 {
 463         TALLOC_CTX *frame = talloc_stackframe();
 464         struct tevent_context *ev;
 465         struct tevent_req *req;
 466         struct timeval end;
 467         NTSTATUS status = NT_STATUS_NO_MEMORY;
 468
 469         ev = samba_tevent_context_init(frame);
 470         if (ev == NULL) {
 471                 goto fail;
 472         }
 473         req = g_lock_lock_send(frame, ev, ctx, name, type);
 474         if (req == NULL) {
 475                 goto fail;
 476         }
 477         end = timeval_current_ofs(timeout.tv_sec, timeout.tv_usec);
 478         if (!tevent_req_set_endtime(req, ev, end)) {
 479                 goto fail;
 480         }
 481         if (!tevent_req_poll_ntstatus(req, ev, &status)) {
 482                 goto fail;
 483         }
 484         status = g_lock_lock_recv(req);
 485  fail:
 486         TALLOC_FREE(frame);
 487         return status;
 488 }
 489
 490 NTSTATUS g_lock_unlock(struct g_lock_ctx *ctx, const char *name)
 491 {
 492         struct server_id self = messaging_server_id(ctx->msg);
 493         struct db_record *rec = NULL;
 494         struct g_lock_rec *locks = NULL;
 495         size_t i, num_locks;
 496         NTSTATUS status;
 497         TDB_DATA value, userdata;
 498
 499         rec = dbwrap_fetch_locked(ctx->db, talloc_tos(),
 500                                   string_term_tdb_data(name));
 501         if (rec == NULL) {
 502                 DEBUG(10, ("fetch_locked(\"%s\") failed\n", name));
 503                 status = NT_STATUS_INTERNAL_ERROR;
 504                 goto done;
 505         }
 506
 507         value = dbwrap_record_get_value(rec);
 508
 509         status = g_lock_get_talloc(talloc_tos(), value, &locks, &num_locks,
 510                                    &userdata.dptr, &userdata.dsize);
 511         if (!NT_STATUS_IS_OK(status)) {
 512                 DBG_DEBUG("g_lock_get for %s failed: %s\n", name,
 513                           nt_errstr(status));
 514                 status = NT_STATUS_FILE_INVALID;
 515                 goto done;
 516         }
 517         for (i=0; i<num_locks; i++) {
 518                 if (serverid_equal(&self, &locks[i].pid)) {
 519                         break;
 520                 }
 521         }
 522         if (i == num_locks) {
 523                 DBG_DEBUG("Lock not found, num_locks=%zu\n", num_locks);
 524                 status = NT_STATUS_NOT_FOUND;
 525                 goto done;
 526         }
 527
 528         locks[i] = locks[num_locks-1];
 529         num_locks -= 1;
 530
 531         if ((num_locks == 0) && (userdata.dsize == 0)) {
 532                 status = dbwrap_record_delete(rec);
 533         } else {
 534                 status = g_lock_record_store(
 535                         rec, locks, num_locks, userdata.dptr, userdata.dsize);
 536         }
 537         if (!NT_STATUS_IS_OK(status)) {
 538                 DBG_WARNING("Could not store record: %s\n", nt_errstr(status));
 539                 goto done;
 540         }
 541
 542         status = NT_STATUS_OK;
 543 done:
 544         TALLOC_FREE(rec);
 545         TALLOC_FREE(locks);
 546         return status;
 547 }
 548
 549 NTSTATUS g_lock_write_data(struct g_lock_ctx *ctx, const char *name,
 550                            const uint8_t *buf, size_t buflen)
 551 {
 552         struct server_id self = messaging_server_id(ctx->msg);
 553         struct db_record *rec = NULL;
 554         struct g_lock_rec *locks = NULL;
 555         size_t i, num_locks;
 556         NTSTATUS status;
 557         TDB_DATA value;
 558
 559         rec = dbwrap_fetch_locked(ctx->db, talloc_tos(),
 560                                   string_term_tdb_data(name));
 561         if (rec == NULL) {
 562                 DEBUG(10, ("fetch_locked(\"%s\") failed\n", name));
 563                 status = NT_STATUS_INTERNAL_ERROR;
 564                 goto done;
 565         }
 566
 567         value = dbwrap_record_get_value(rec);
 568
 569         status = g_lock_get_talloc(talloc_tos(), value, &locks, &num_locks,
 570                                    NULL, NULL);
 571         if (!NT_STATUS_IS_OK(status)) {
 572                 DBG_DEBUG("g_lock_get for %s failed: %s\n", name,
 573                           nt_errstr(status));
 574                 status = NT_STATUS_FILE_INVALID;
 575                 goto done;
 576         }
 577
 578         for (i=0; i<num_locks; i++) {
 579                 if (server_id_equal(&self, &locks[i].pid) &&
 580                     (locks[i].lock_type == G_LOCK_WRITE)) {
 581                         break;
 582                 }
 583         }
 584         if (i == num_locks) {
 585                 DBG_DEBUG("Not locked by us\n");
 586                 status = NT_STATUS_NOT_LOCKED;
 587                 goto done;
 588         }
 589
 590         status = g_lock_record_store(rec, locks, num_locks, buf, buflen);
 591
 592 done:
 593         TALLOC_FREE(locks);
 594         TALLOC_FREE(rec);
 595         return status;
 596 }
 597
 598 struct g_lock_locks_state {
 599         int (*fn)(const char *name, void *private_data);
 600         void *private_data;
 601 };
 602
 603 static int g_lock_locks_fn(struct db_record *rec, void *priv)
 604 {
 605         TDB_DATA key;
 606         struct g_lock_locks_state *state = (struct g_lock_locks_state *)priv;
 607
 608         key = dbwrap_record_get_key(rec);
 609         if ((key.dsize == 0) || (key.dptr[key.dsize-1] != 0)) {
 610                 DEBUG(1, ("invalid key in g_lock.tdb, ignoring\n"));
 611                 return 0;
 612         }
 613         return state->fn((char *)key.dptr, state->private_data);
 614 }
 615
 616 int g_lock_locks(struct g_lock_ctx *ctx,
 617                  int (*fn)(const char *name, void *private_data),
 618                  void *private_data)
 619 {
 620         struct g_lock_locks_state state;
 621         NTSTATUS status;
 622         int count;
 623
 624         state.fn = fn;
 625         state.private_data = private_data;
 626
 627         status = dbwrap_traverse_read(ctx->db, g_lock_locks_fn, &state, &count);
 628         if (!NT_STATUS_IS_OK(status)) {
 629                 return -1;
 630         }
 631         return count;
 632 }
 633
 634 NTSTATUS g_lock_dump(struct g_lock_ctx *ctx, const char *name,
 635                      void (*fn)(const struct g_lock_rec *locks,
 636                                 size_t num_locks,
 637                                 const uint8_t *data,
 638                                 size_t datalen,
 639                                 void *private_data),
 640                      void *private_data)
 641 {
 642         TDB_DATA data;
 643         size_t num_locks;
 644         struct g_lock_rec *locks = NULL;
 645         uint8_t *userdata;
 646         size_t userdatalen;
 647         NTSTATUS status;
 648
 649         status = dbwrap_fetch_bystring(ctx->db, talloc_tos(), name, &data);
 650         if (!NT_STATUS_IS_OK(status)) {
 651                 return status;
 652         }
 653
 654         if ((data.dsize == 0) || (data.dptr == NULL)) {
 655                 return NT_STATUS_OK;
 656         }
 657
 658         status = g_lock_get_talloc(talloc_tos(), data, &locks, &num_locks,
 659                                    &userdata, &userdatalen);
 660
 661         if (!NT_STATUS_IS_OK(status)) {
 662                 DBG_DEBUG("g_lock_get for %s failed: %s\n", name,
 663                           nt_errstr(status));
 664                 TALLOC_FREE(data.dptr);
 665                 return NT_STATUS_INTERNAL_ERROR;
 666         }
 667
 668         fn(locks, num_locks, userdata, userdatalen, private_data);
 669
 670         TALLOC_FREE(locks);
 671         TALLOC_FREE(data.dptr);
 672         return NT_STATUS_OK;
 673 }
 674
 675 static bool g_lock_init_all(TALLOC_CTX *mem_ctx,
 676                             struct tevent_context **pev,
 677                             struct messaging_context **pmsg,
 678                             struct g_lock_ctx **pg_ctx)
 679 {
 680         struct tevent_context *ev = NULL;
 681         struct messaging_context *msg = NULL;
 682         struct g_lock_ctx *g_ctx = NULL;
 683
 684         ev = samba_tevent_context_init(mem_ctx);
 685         if (ev == NULL) {
 686                 d_fprintf(stderr, "ERROR: could not init event context\n");
 687                 goto fail;
 688         }
 689         msg = messaging_init(mem_ctx, ev);
 690         if (msg == NULL) {
 691                 d_fprintf(stderr, "ERROR: could not init messaging context\n");
 692                 goto fail;
 693         }
 694         g_ctx = g_lock_ctx_init(mem_ctx, msg);
 695         if (g_ctx == NULL) {
 696                 d_fprintf(stderr, "ERROR: could not init g_lock context\n");
 697                 goto fail;
 698         }
 699
 700         *pev = ev;
 701         *pmsg = msg;
 702         *pg_ctx = g_ctx;
 703         return true;
 704 fail:
 705         TALLOC_FREE(g_ctx);
 706         TALLOC_FREE(msg);
 707         TALLOC_FREE(ev);
 708         return false;
 709 }
 710
 711 NTSTATUS g_lock_do(const char *name, enum g_lock_type lock_type,
 712                    struct timeval timeout,
 713                    void (*fn)(void *private_data), void *private_data)
 714 {
 715         struct tevent_context *ev = NULL;
 716         struct messaging_context *msg = NULL;
 717         struct g_lock_ctx *g_ctx = NULL;
 718         NTSTATUS status;
 719
 720         if (!g_lock_init_all(talloc_tos(), &ev, &msg, &g_ctx)) {
 721                 status = NT_STATUS_ACCESS_DENIED;
 722                 goto done;
 723         }
 724
 725         status = g_lock_lock(g_ctx, name, lock_type, timeout);
 726         if (!NT_STATUS_IS_OK(status)) {
 727                 goto done;
 728         }
 729         fn(private_data);
 730         g_lock_unlock(g_ctx, name);
 731
 732 done:
 733         TALLOC_FREE(g_ctx);
 734         TALLOC_FREE(msg);
 735         TALLOC_FREE(ev);
 736         return status;
 737 }