source/lib/ldb/modules/paged_results.c

   1 /*
   2    ldb database library
   3
   4    Copyright (C) Simo Sorce  2005-2006
   5
   6      ** NOTE! The following LGPL license applies to the ldb
   7      ** library. This does NOT imply that all of Samba is released
   8      ** under the LGPL
   9
  10    This library is free software; you can redistribute it and/or
  11    modify it under the terms of the GNU Lesser General Public
  12    License as published by the Free Software Foundation; either
  13    version 2 of the License, or (at your option) any later version.
  14
  15    This library 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 GNU
  18    Lesser General Public License for more details.
  19
  20    You should have received a copy of the GNU Lesser General Public
  21    License along with this library; if not, write to the Free Software
  22    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23 */
  24
  25 /*
  26  *  Name: paged_result
  27  *
  28  *  Component: ldb paged results control module
  29  *
  30  *  Description: this module caches a complete search and sends back
  31  *               results in chunks as asked by the client
  32  *
  33  *  Author: Simo Sorce
  34  */
  35
  36 #include "includes.h"
  37 #include "ldb/include/includes.h"
  38
  39 struct message_store {
  40         /* keep the whole ldb_reply as an optimization
  41          * instead of freeing and talloc-ing the container
  42          * on each result */
  43         struct ldb_reply *r;
  44         struct message_store *next;
  45 };
  46
  47 struct results_store {
  48         char *cookie;
  49         time_t timestamp;
  50         int num_sent; /* To be removed */
  51         struct ldb_result *result; /* To be removed */
  52         struct results_store *prev;
  53         struct results_store *next;
  54
  55         struct message_store *first;
  56         struct message_store *last;
  57         int num_entries;
  58
  59         struct message_store *first_ref;
  60         struct message_store *last_ref;
  61
  62         struct ldb_control **controls;
  63
  64         struct ldb_request *req;
  65 };
  66
  67 struct private_data {
  68
  69         int next_free_id;
  70         struct results_store *store;
  71
  72 };
  73
  74 int store_destructor(struct results_store *store)
  75 {
  76         if (store->prev) {
  77                 store->prev->next = store->next;
  78         }
  79         if (store->next) {
  80                 store->next->prev = store->prev;
  81         }
  82
  83         return 0;
  84 }
  85
  86 static struct results_store *new_store(struct private_data *priv)
  87 {
  88         struct results_store *newr;
  89         int new_id = priv->next_free_id++;
  90
  91         /* TODO: we should have a limit on the number of
  92          * outstanding paged searches
  93          */
  94
  95         newr = talloc(priv, struct results_store);
  96         if (!newr) return NULL;
  97
  98         newr->cookie = talloc_asprintf(newr, "%d", new_id);
  99         if (!newr->cookie) {
 100                 talloc_free(newr);
 101                 return NULL;
 102         }
 103
 104         newr->timestamp = time(NULL);
 105
 106         newr->num_sent = 0; /* To be removed */
 107         newr->result = NULL; /* To be removed */
 108
 109         newr->first = NULL;
 110         newr->num_entries = 0;
 111         newr->first_ref = NULL;
 112         newr->controls = NULL;
 113
 114         /* put this entry as first */
 115         newr->prev = NULL;
 116         newr->next = priv->store;
 117         if (priv->store != NULL) priv->store->prev = newr;
 118         priv->store = newr;
 119
 120         talloc_set_destructor(newr, store_destructor);
 121
 122         return newr;
 123 }
 124
 125 struct paged_context {
 126         struct ldb_module *module;
 127         void *up_context;
 128         int (*up_callback)(struct ldb_context *, void *, struct ldb_reply *);
 129
 130         int size;
 131
 132         struct results_store *store;
 133 };
 134
 135 static struct ldb_handle *init_handle(void *mem_ctx, struct ldb_module *module,
 136                                             void *context,
 137                                             int (*callback)(struct ldb_context *, void *, struct ldb_reply *))
 138 {
 139         struct paged_context *ac;
 140         struct ldb_handle *h;
 141
 142         h = talloc_zero(mem_ctx, struct ldb_handle);
 143         if (h == NULL) {
 144                 ldb_set_errstring(module->ldb, "Out of Memory");
 145                 return NULL;
 146         }
 147
 148         h->module = module;
 149
 150         ac = talloc_zero(h, struct paged_context);
 151         if (ac == NULL) {
 152                 ldb_set_errstring(module->ldb, "Out of Memory");
 153                 talloc_free(h);
 154                 return NULL;
 155         }
 156
 157         h->private_data = (void *)ac;
 158
 159         h->state = LDB_ASYNC_INIT;
 160         h->status = LDB_SUCCESS;
 161
 162         ac->module = module;
 163         ac->up_context = context;
 164         ac->up_callback = callback;
 165
 166         return h;
 167 }
 168
 169 static int paged_search_callback(struct ldb_context *ldb, void *context, struct ldb_reply *ares)
 170 {
 171         struct paged_context *ac = NULL;
 172
 173         if (!context || !ares) {
 174                 ldb_set_errstring(ldb, "NULL Context or Result in callback");
 175                 goto error;
 176         }
 177
 178         ac = talloc_get_type(context, struct paged_context);
 179
 180         if (ares->type == LDB_REPLY_ENTRY) {
 181                 if (ac->store->first == NULL) {
 182                         ac->store->first = ac->store->last = talloc(ac->store, struct message_store);
 183                 } else {
 184                         ac->store->last->next = talloc(ac->store, struct message_store);
 185                         ac->store->last = ac->store->last->next;
 186                 }
 187                 if (ac->store->last == NULL) {
 188                         goto error;
 189                 }
 190
 191                 ac->store->num_entries++;
 192
 193                 ac->store->last->r = talloc_steal(ac->store->last, ares);
 194                 ac->store->last->next = NULL;
 195         }
 196
 197         if (ares->type == LDB_REPLY_REFERRAL) {
 198                 if (ac->store->first_ref == NULL) {
 199                         ac->store->first_ref = ac->store->last_ref = talloc(ac->store, struct message_store);
 200                 } else {
 201                         ac->store->last_ref->next = talloc(ac->store, struct message_store);
 202                         ac->store->last_ref = ac->store->last_ref->next;
 203                 }
 204                 if (ac->store->last_ref == NULL) {
 205                         goto error;
 206                 }
 207
 208                 ac->store->last_ref->r = talloc_steal(ac->store->last, ares);
 209                 ac->store->last_ref->next = NULL;
 210         }
 211
 212         if (ares->type == LDB_REPLY_DONE) {
 213                 ac->store->controls = talloc_move(ac->store, ares->controls);
 214                 talloc_free(ares);
 215         }
 216
 217         return LDB_SUCCESS;
 218
 219 error:
 220         talloc_free(ares);
 221         return LDB_ERR_OPERATIONS_ERROR;
 222 }
 223
 224 static int paged_search(struct ldb_module *module, struct ldb_request *req)
 225 {
 226         struct ldb_control *control;
 227         struct private_data *private_data;
 228         struct ldb_paged_control *paged_ctrl;
 229         struct ldb_control **saved_controls;
 230         struct paged_context *ac;
 231         struct ldb_handle *h;
 232         int ret;
 233
 234         /* check if there's a paged request control */
 235         control = get_control_from_list(req->controls, LDB_CONTROL_PAGED_RESULTS_OID);
 236         if (control == NULL) {
 237                 /* not found go on */
 238                 return ldb_next_request(module, req);
 239         }
 240
 241         private_data = talloc_get_type(module->private_data, struct private_data);
 242
 243         req->handle = NULL;
 244
 245         if (!req->callback || !req->context) {
 246                 ldb_set_errstring(module->ldb,
 247                                   "Async interface called with NULL callback function or NULL context");
 248                 return LDB_ERR_OPERATIONS_ERROR;
 249         }
 250
 251         paged_ctrl = talloc_get_type(control->data, struct ldb_paged_control);
 252         if (!paged_ctrl) {
 253                 return LDB_ERR_PROTOCOL_ERROR;
 254         }
 255
 256         h = init_handle(req, module, req->context, req->callback);
 257         if (!h) {
 258                 return LDB_ERR_OPERATIONS_ERROR;
 259         }
 260         ac = talloc_get_type(h->private_data, struct paged_context);
 261
 262         ac->size = paged_ctrl->size;
 263
 264         /* check if it is a continuation search the store */
 265         if (paged_ctrl->cookie_len == 0) {
 266
 267                 ac->store = new_store(private_data);
 268                 if (ac->store == NULL) {
 269                         talloc_free(h);
 270                         return LDB_ERR_UNWILLING_TO_PERFORM;
 271                 }
 272
 273                 ac->store->req = talloc(ac->store, struct ldb_request);
 274                 if (!ac->store->req)
 275                         return LDB_ERR_OPERATIONS_ERROR;
 276
 277                 ac->store->req->operation = req->operation;
 278                 ac->store->req->op.search.base = req->op.search.base;
 279                 ac->store->req->op.search.scope = req->op.search.scope;
 280                 ac->store->req->op.search.tree = req->op.search.tree;
 281                 ac->store->req->op.search.attrs = req->op.search.attrs;
 282                 ac->store->req->controls = req->controls;
 283
 284                 /* save it locally and remove it from the list */
 285                 /* we do not need to replace them later as we
 286                  * are keeping the original req intact */
 287                 if (!save_controls(control, ac->store->req, &saved_controls)) {
 288                         return LDB_ERR_OPERATIONS_ERROR;
 289                 }
 290
 291                 ac->store->req->context = ac;
 292                 ac->store->req->callback = paged_search_callback;
 293                 ldb_set_timeout_from_prev_req(module->ldb, req, ac->store->req);
 294
 295                 ret = ldb_next_request(module, ac->store->req);
 296
 297         } else {
 298                 struct results_store *current = NULL;
 299
 300                 for (current = private_data->store; current; current = current->next) {
 301                         if (strcmp(current->cookie, paged_ctrl->cookie) == 0) {
 302                                 current->timestamp = time(NULL);
 303                                 break;
 304                         }
 305                 }
 306                 if (current == NULL) {
 307                         talloc_free(h);
 308                         return LDB_ERR_UNWILLING_TO_PERFORM;
 309                 }
 310
 311                 ac->store = current;
 312                 ret = LDB_SUCCESS;
 313         }
 314
 315         req->handle = h;
 316
 317         /* check if it is an abandon */
 318         if (ac->size == 0) {
 319                 talloc_free(ac->store);
 320                 h->status = LDB_SUCCESS;
 321                 h->state = LDB_ASYNC_DONE;
 322                 return LDB_SUCCESS;
 323         }
 324
 325         /* TODO: age out old outstanding requests */
 326
 327         return ret;
 328
 329 }
 330
 331 static int paged_results(struct ldb_handle *handle)
 332 {
 333         struct paged_context *ac;
 334         struct ldb_paged_control *paged;
 335         struct ldb_reply *ares;
 336         struct message_store *msg;
 337         int i, num_ctrls, ret;
 338
 339         ac = talloc_get_type(handle->private_data, struct paged_context);
 340
 341         if (ac->store == NULL)
 342                 return LDB_ERR_OPERATIONS_ERROR;
 343
 344         while (ac->store->num_entries > 0 && ac->size > 0) {
 345                 msg = ac->store->first;
 346                 ret = ac->up_callback(ac->module->ldb, ac->up_context, msg->r);
 347                 if (ret != LDB_SUCCESS) {
 348                         handle->status = ret;
 349                         handle->state = LDB_ASYNC_DONE;
 350                         return ret;
 351                 }
 352
 353                 ac->store->first = msg->next;
 354                 talloc_free(msg);
 355                 ac->store->num_entries--;
 356                 ac->size--;
 357         }
 358
 359         handle->state = LDB_ASYNC_DONE;
 360
 361         while (ac->store->first_ref != NULL) {
 362                 msg = ac->store->first_ref;
 363                 ret = ac->up_callback(ac->module->ldb, ac->up_context, msg->r);
 364                 if (ret != LDB_SUCCESS) {
 365                         handle->status = ret;
 366                         handle->state = LDB_ASYNC_DONE;
 367                         return ret;
 368                 }
 369
 370                 ac->store->first_ref = msg->next;
 371                 talloc_free(msg);
 372         }
 373
 374         ares = talloc_zero(ac->store, struct ldb_reply);
 375         if (ares == NULL) {
 376                 handle->status = LDB_ERR_OPERATIONS_ERROR;
 377                 return handle->status;
 378         }
 379         num_ctrls = 2;
 380         i = 0;
 381
 382         if (ac->store->controls != NULL) {
 383                 ares->controls = ac->store->controls;
 384                 while (ares->controls[i]) i++; /* counting */
 385
 386                 ares->controls = talloc_move(ares, ac->store->controls);
 387                 num_ctrls += i;
 388         }
 389
 390         ares->controls = talloc_realloc(ares, ares->controls, struct ldb_control *, num_ctrls);
 391         if (ares->controls == NULL) {
 392                 handle->status = LDB_ERR_OPERATIONS_ERROR;
 393                 return handle->status;
 394         }
 395
 396         ares->controls[i] = talloc(ares->controls, struct ldb_control);
 397         if (ares->controls[i] == NULL) {
 398                 handle->status = LDB_ERR_OPERATIONS_ERROR;
 399                 return handle->status;
 400         }
 401
 402         ares->controls[i]->oid = talloc_strdup(ares->controls[i], LDB_CONTROL_PAGED_RESULTS_OID);
 403         if (ares->controls[i]->oid == NULL) {
 404                 handle->status = LDB_ERR_OPERATIONS_ERROR;
 405                 return handle->status;
 406         }
 407
 408         ares->controls[i]->critical = 0;
 409         ares->controls[i + 1] = NULL;
 410
 411         paged = talloc(ares->controls[i], struct ldb_paged_control);
 412         if (paged == NULL) {
 413                 handle->status = LDB_ERR_OPERATIONS_ERROR;
 414                 return handle->status;
 415         }
 416
 417         ares->controls[i]->data = paged;
 418
 419         if (ac->size > 0) {
 420                 paged->size = 0;
 421                 paged->cookie = NULL;
 422                 paged->cookie_len = 0;
 423         } else {
 424                 paged->size = ac->store->num_entries;
 425                 paged->cookie = talloc_strdup(paged, ac->store->cookie);
 426                 paged->cookie_len = strlen(paged->cookie) + 1;
 427         }
 428
 429         ares->type = LDB_REPLY_DONE;
 430
 431         ret = ac->up_callback(ac->module->ldb, ac->up_context, ares);
 432
 433         handle->status = ret;
 434
 435         return ret;
 436 }
 437
 438 static int paged_wait(struct ldb_handle *handle, enum ldb_wait_type type)
 439 {
 440         struct paged_context *ac;
 441         int ret;
 442
 443         if (!handle || !handle->private_data) {
 444                 return LDB_ERR_OPERATIONS_ERROR;
 445         }
 446
 447         if (handle->state == LDB_ASYNC_DONE) {
 448                 return handle->status;
 449         }
 450
 451         handle->state = LDB_ASYNC_PENDING;
 452
 453         ac = talloc_get_type(handle->private_data, struct paged_context);
 454
 455         if (ac->store->req->handle->state == LDB_ASYNC_DONE) {
 456                 /* if lower level is finished we do not need to call it anymore */
 457                 /* return all we have until size == 0 or we empty storage */
 458                 ret = paged_results(handle);
 459
 460                 /* we are done, if num_entries is zero free the storage
 461                  * as that mean we delivered the last batch */
 462                 if (ac->store->num_entries == 0) {
 463                         talloc_free(ac->store);
 464                 }
 465
 466                 return ret;
 467         }
 468
 469         if (type == LDB_WAIT_ALL) {
 470                 while (ac->store->req->handle->state != LDB_ASYNC_DONE) {
 471                         ret = ldb_wait(ac->store->req->handle, type);
 472                         if (ret != LDB_SUCCESS) {
 473                                 handle->state = LDB_ASYNC_DONE;
 474                                 handle->status = ret;
 475                                 return ret;
 476                         }
 477                 }
 478
 479                 ret = paged_results(handle);
 480
 481                 /* we are done, if num_entries is zero free the storage
 482                  * as that mean we delivered the last batch */
 483                 if (ac->store->num_entries == 0) {
 484                         talloc_free(ac->store);
 485                 }
 486
 487                 return ret;
 488         }
 489
 490         ret = ldb_wait(ac->store->req->handle, type);
 491         if (ret != LDB_SUCCESS) {
 492                 handle->state = LDB_ASYNC_DONE;
 493                 handle->status = ret;
 494                 return ret;
 495         }
 496
 497         handle->status = ret;
 498
 499         if (ac->store->num_entries >= ac->size ||
 500             ac->store->req->handle->state == LDB_ASYNC_DONE) {
 501
 502                 ret = paged_results(handle);
 503
 504                 /* we are done, if num_entries is zero free the storage
 505                  * as that mean we delivered the last batch */
 506                 if (ac->store->num_entries == 0) {
 507                         talloc_free(ac->store);
 508                 }
 509         }
 510
 511         return ret;
 512 }
 513
 514 static int paged_request_init(struct ldb_module *module)
 515 {
 516         struct private_data *data;
 517         struct ldb_request *req;
 518         int ret;
 519
 520         data = talloc(module, struct private_data);
 521         if (data == NULL) {
 522                 return LDB_ERR_OTHER;
 523         }
 524
 525         data->next_free_id = 1;
 526         data->store = NULL;
 527         module->private_data = data;
 528
 529         req = talloc(module, struct ldb_request);
 530         if (req == NULL) {
 531                 return LDB_ERR_OPERATIONS_ERROR;
 532         }
 533
 534         req->operation = LDB_REQ_REGISTER_CONTROL;
 535         req->op.reg_control.oid = LDB_CONTROL_PAGED_RESULTS_OID;
 536         req->controls = NULL;
 537
 538         ret = ldb_request(module->ldb, req);
 539         if (ret != LDB_SUCCESS) {
 540                 ldb_debug(module->ldb, LDB_DEBUG_ERROR, "paged_request: Unable to register control with rootdse!\n");
 541                 talloc_free(req);
 542                 return LDB_ERR_OTHER;
 543         }
 544
 545         talloc_free(req);
 546         return ldb_next_init(module);
 547 }
 548
 549 static const struct ldb_module_ops paged_ops = {
 550         .name           = "paged_results",
 551         .search         = paged_search,
 552         .wait           = paged_wait,
 553         .init_context   = paged_request_init
 554 };
 555
 556 int ldb_paged_results_init(void)
 557 {
 558         return ldb_register_module(&paged_ops);
 559 }
 560