source3/lib/ldb/modules/paged_searches.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 3 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, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 /*
  25  *  Name: paged_searches
  26  *
  27  *  Component: ldb paged searches module
  28  *
  29  *  Description: this module detects if the remote ldap server supports
  30  *               paged results and use them to transparently access all objects
  31  *
  32  *  Author: Simo Sorce
  33  */
  34
  35 #include "includes.h"
  36 #include "ldb/include/includes.h"
  37
  38 #define PS_DEFAULT_PAGE_SIZE 500
  39 /* 500 objects per query seem to be a decent compromise
  40  * the default AD limit per request is 1000 entries */
  41
  42 struct private_data {
  43
  44         bool paged_supported;
  45 };
  46
  47 struct ps_context {
  48         struct ldb_module *module;
  49         void *up_context;
  50         int (*up_callback)(struct ldb_context *, void *, struct ldb_reply *);
  51
  52         struct ldb_request *orig_req;
  53
  54         struct ldb_request *new_req;
  55
  56         bool pending;
  57
  58         char **saved_referrals;
  59         int num_referrals;
  60 };
  61
  62 static struct ldb_handle *init_handle(void *mem_ctx, struct ldb_module *module,
  63                                             void *context,
  64                                             int (*callback)(struct ldb_context *, void *, struct ldb_reply *))
  65 {
  66         struct ps_context *ac;
  67         struct ldb_handle *h;
  68
  69         h = talloc_zero(mem_ctx, struct ldb_handle);
  70         if (h == NULL) {
  71                 ldb_set_errstring(module->ldb, "Out of Memory");
  72                 return NULL;
  73         }
  74
  75         h->module = module;
  76
  77         ac = talloc_zero(h, struct ps_context);
  78         if (ac == NULL) {
  79                 ldb_set_errstring(module->ldb, "Out of Memory");
  80                 talloc_free(h);
  81                 return NULL;
  82         }
  83
  84         h->private_data = (void *)ac;
  85
  86         h->state = LDB_ASYNC_INIT;
  87         h->status = LDB_SUCCESS;
  88
  89         ac->module = module;
  90         ac->up_context = context;
  91         ac->up_callback = callback;
  92
  93         ac->pending = False;
  94         ac->saved_referrals = NULL;
  95         ac->num_referrals = 0;
  96
  97         return h;
  98 }
  99
 100 static int check_ps_continuation(struct ldb_reply *ares, struct ps_context *ac)
 101 {
 102         struct ldb_paged_control *rep_control, *req_control;
 103
 104         /* look up our paged control */
 105         if (!ares->controls || strcmp(LDB_CONTROL_PAGED_RESULTS_OID, ares->controls[0]->oid) != 0) {
 106                 /* something wrong here */
 107                 return LDB_ERR_OPERATIONS_ERROR;
 108         }
 109
 110         rep_control = talloc_get_type(ares->controls[0]->data, struct ldb_paged_control);
 111         if (rep_control->cookie_len == 0) {
 112                 /* we are done */
 113                 ac->pending = False;
 114                 return LDB_SUCCESS;
 115         }
 116
 117         /* more processing required */
 118         /* let's fill in the request control with the new cookie */
 119         /* if there's a reply control we must find a request
 120          * control matching it */
 121
 122         if (strcmp(LDB_CONTROL_PAGED_RESULTS_OID, ac->new_req->controls[0]->oid) != 0) {
 123                 /* something wrong here */
 124                 return LDB_ERR_OPERATIONS_ERROR;
 125         }
 126
 127         req_control = talloc_get_type(ac->new_req->controls[0]->data, struct ldb_paged_control);
 128
 129         if (req_control->cookie) {
 130                 talloc_free(req_control->cookie);
 131         }
 132
 133         req_control->cookie = talloc_memdup(req_control,
 134                                             rep_control->cookie,
 135                                             rep_control->cookie_len);
 136         req_control->cookie_len = rep_control->cookie_len;
 137
 138         ac->pending = True;
 139         return LDB_SUCCESS;
 140 }
 141
 142 static int store_referral(char *referral, struct ps_context *ac)
 143 {
 144         ac->saved_referrals = talloc_realloc(ac, ac->saved_referrals, char *, ac->num_referrals + 2);
 145         if (!ac->saved_referrals) {
 146                 return LDB_ERR_OPERATIONS_ERROR;
 147         }
 148
 149         ac->saved_referrals[ac->num_referrals] = talloc_strdup(ac->saved_referrals, referral);
 150         if (!ac->saved_referrals[ac->num_referrals]) {
 151                 return LDB_ERR_OPERATIONS_ERROR;
 152         }
 153
 154         ac->num_referrals++;
 155         ac->saved_referrals[ac->num_referrals] = NULL;
 156
 157         return LDB_SUCCESS;
 158 }
 159
 160 static int send_referrals(struct ldb_context *ldb, struct ps_context *ac)
 161 {
 162         struct ldb_reply *ares;
 163         int i;
 164
 165         for (i = 0; i < ac->num_referrals; i++) {
 166                 ares = talloc_zero(ac, struct ldb_reply);
 167                 if (!ares) {
 168                         return LDB_ERR_OPERATIONS_ERROR;
 169                 }
 170
 171                 ares->type = LDB_REPLY_REFERRAL;
 172                 ares->referral = ac->saved_referrals[i];
 173
 174                 ac->up_callback(ldb, ac->up_context, ares);
 175         }
 176
 177         return LDB_SUCCESS;
 178 }
 179
 180 static int ps_callback(struct ldb_context *ldb, void *context, struct ldb_reply *ares)
 181 {
 182         struct ps_context *ac = NULL;
 183         int ret = LDB_ERR_OPERATIONS_ERROR;
 184
 185         if (!context || !ares) {
 186                 ldb_set_errstring(ldb, "NULL Context or Result in callback");
 187                 goto error;
 188         }
 189
 190         ac = talloc_get_type(context, struct ps_context);
 191
 192         switch (ares->type) {
 193         case LDB_REPLY_ENTRY:
 194                 ac->up_callback(ldb, ac->up_context, ares);
 195                 break;
 196
 197         case LDB_REPLY_REFERRAL:
 198                 ret = store_referral(ares->referral, ac);
 199                 if (ret != LDB_SUCCESS) {
 200                         goto error;
 201                 }
 202                 break;
 203
 204         case LDB_REPLY_DONE:
 205                 ret = check_ps_continuation(ares, ac);
 206                 if (ret != LDB_SUCCESS) {
 207                         goto error;
 208                 }
 209                 if (!ac->pending) {
 210                         /* send referrals */
 211                         ret = send_referrals(ldb, ac);
 212                         if (ret != LDB_SUCCESS) {
 213                                 goto error;
 214                         }
 215
 216                         /* send REPLY_DONE */
 217                         ac->up_callback(ldb, ac->up_context, ares);
 218                 }
 219                 break;
 220         default:
 221                 goto error;
 222         }
 223
 224         return LDB_SUCCESS;
 225
 226 error:
 227         talloc_free(ares);
 228         return ret;
 229 }
 230
 231 static int ps_search(struct ldb_module *module, struct ldb_request *req)
 232 {
 233         struct private_data *private_data;
 234         struct ldb_paged_control *control;
 235         struct ps_context *ac;
 236         struct ldb_handle *h;
 237
 238         private_data = talloc_get_type(module->private_data, struct private_data);
 239
 240         /* check if paging is supported and if there is a any control */
 241         if (!private_data || !private_data->paged_supported || req->controls) {
 242                 /* do not touch this request paged controls not
 243                  * supported or explicit controls have been set or we
 244                  * are just not setup yet */
 245                 return ldb_next_request(module, req);
 246         }
 247
 248         if (!req->callback || !req->context) {
 249                 ldb_set_errstring(module->ldb,
 250                                   "Async interface called with NULL callback function or NULL context");
 251                 return LDB_ERR_OPERATIONS_ERROR;
 252         }
 253
 254         h = init_handle(req, module, req->context, req->callback);
 255         if (!h) {
 256                 return LDB_ERR_OPERATIONS_ERROR;
 257         }
 258         ac = talloc_get_type(h->private_data, struct ps_context);
 259
 260         ac->new_req = talloc(ac, struct ldb_request);
 261         if (!ac->new_req) return LDB_ERR_OPERATIONS_ERROR;
 262
 263         ac->new_req->controls = talloc_array(ac->new_req, struct ldb_control *, 2);
 264         if (!ac->new_req->controls) return LDB_ERR_OPERATIONS_ERROR;
 265
 266         ac->new_req->controls[0] = talloc(ac->new_req->controls, struct ldb_control);
 267         if (!ac->new_req->controls[0]) return LDB_ERR_OPERATIONS_ERROR;
 268
 269         control = talloc(ac->new_req->controls[0], struct ldb_paged_control);
 270         if (!control) return LDB_ERR_OPERATIONS_ERROR;
 271
 272         control->size = PS_DEFAULT_PAGE_SIZE;
 273         control->cookie = NULL;
 274         control->cookie_len = 0;
 275
 276         ac->new_req->controls[0]->oid = LDB_CONTROL_PAGED_RESULTS_OID;
 277         ac->new_req->controls[0]->critical = 1;
 278         ac->new_req->controls[0]->data = control;
 279
 280         ac->new_req->controls[1] = NULL;
 281
 282         ac->new_req->operation = req->operation;
 283         ac->new_req->op.search.base = req->op.search.base;
 284         ac->new_req->op.search.scope = req->op.search.scope;
 285         ac->new_req->op.search.tree = req->op.search.tree;
 286         ac->new_req->op.search.attrs = req->op.search.attrs;
 287         ac->new_req->context = ac;
 288         ac->new_req->callback = ps_callback;
 289         ldb_set_timeout_from_prev_req(module->ldb, req, ac->new_req);
 290
 291         req->handle = h;
 292
 293         return ldb_next_request(module, ac->new_req);
 294 }
 295
 296 static int ps_continuation(struct ldb_handle *handle)
 297 {
 298         struct ps_context *ac;
 299
 300         if (!handle || !handle->private_data) {
 301                 return LDB_ERR_OPERATIONS_ERROR;
 302         }
 303
 304         ac = talloc_get_type(handle->private_data, struct ps_context);
 305
 306         /* reset the requests handle */
 307         ac->new_req->handle = NULL;
 308
 309         return ldb_next_request(handle->module, ac->new_req);
 310 }
 311
 312 static int ps_wait_none(struct ldb_handle *handle)
 313 {
 314         struct ps_context *ac;
 315         int ret;
 316
 317         if (!handle || !handle->private_data) {
 318                 return LDB_ERR_OPERATIONS_ERROR;
 319         }
 320
 321         if (handle->state == LDB_ASYNC_DONE) {
 322                 return handle->status;
 323         }
 324
 325         handle->state = LDB_ASYNC_PENDING;
 326         handle->status = LDB_SUCCESS;
 327
 328         ac = talloc_get_type(handle->private_data, struct ps_context);
 329
 330         ret = ldb_wait(ac->new_req->handle, LDB_WAIT_NONE);
 331
 332         if (ret != LDB_SUCCESS) {
 333                 handle->status = ret;
 334                 goto done;
 335         }
 336
 337         if (ac->new_req->handle->status != LDB_SUCCESS) {
 338                 handle->status = ac->new_req->handle->status;
 339                 goto done;
 340         }
 341
 342         if (ac->new_req->handle->state != LDB_ASYNC_DONE) {
 343                 return LDB_SUCCESS;
 344         }
 345
 346         /* see if we need to send another request for the next batch */
 347         if (ac->pending) {
 348                 ret = ps_continuation(handle);
 349                 if (ret != LDB_SUCCESS) {
 350                         handle->status = ret;
 351                         goto done;
 352                 }
 353
 354                 /* continue the search with the next request */
 355                 return LDB_SUCCESS;
 356         }
 357
 358         ret = LDB_SUCCESS;
 359
 360 done:
 361         handle->state = LDB_ASYNC_DONE;
 362         return ret;
 363 }
 364
 365 static int ps_wait_all(struct ldb_handle *handle)
 366 {
 367         int ret;
 368
 369         while (handle->state != LDB_ASYNC_DONE) {
 370                 ret = ps_wait_none(handle);
 371                 if (ret != LDB_SUCCESS) {
 372                         return ret;
 373                 }
 374         }
 375
 376         return handle->status;
 377 }
 378
 379 static int ps_wait(struct ldb_handle *handle, enum ldb_wait_type type)
 380 {
 381         if (type == LDB_WAIT_ALL) {
 382                 return ps_wait_all(handle);
 383         } else {
 384                 return ps_wait_none(handle);
 385         }
 386 }
 387
 388 static int check_supported_paged(struct ldb_context *ldb, void *context,
 389                                  struct ldb_reply *ares)
 390 {
 391         struct private_data *data;
 392         data = talloc_get_type(context,
 393                                struct private_data);
 394         if (ares->type == LDB_REPLY_ENTRY) {
 395                 if (ldb_msg_check_string_attribute(ares->message,
 396                                                    "supportedControl",
 397                                                    LDB_CONTROL_PAGED_RESULTS_OID)) {
 398                         data->paged_supported = True;
 399                 }
 400         }
 401         return LDB_SUCCESS;
 402 }
 403
 404
 405 static int ps_init(struct ldb_module *module)
 406 {
 407         static const char *attrs[] = { "supportedControl", NULL };
 408         struct private_data *data;
 409         int ret;
 410         struct ldb_request *req;
 411
 412         data = talloc(module, struct private_data);
 413         if (data == NULL) {
 414                 return LDB_ERR_OTHER;
 415         }
 416         module->private_data = data;
 417         data->paged_supported = False;
 418
 419         req = talloc(module, struct ldb_request);
 420         if (req == NULL) {
 421                 ldb_set_errstring(module->ldb, "Out of Memory");
 422                 return LDB_ERR_OPERATIONS_ERROR;
 423         }
 424
 425         req->operation = LDB_SEARCH;
 426         req->op.search.base = ldb_dn_new(req);
 427         req->op.search.scope = LDB_SCOPE_BASE;
 428
 429         req->op.search.tree = ldb_parse_tree(req, "objectClass=*");
 430         if (req->op.search.tree == NULL) {
 431                 ldb_set_errstring(module->ldb, "Unable to parse search expression");
 432                 talloc_free(req);
 433                 return LDB_ERR_OPERATIONS_ERROR;
 434         }
 435
 436         req->op.search.attrs = attrs;
 437         req->controls = NULL;
 438         req->context = data;
 439         req->callback = check_supported_paged;
 440         ldb_set_timeout(module->ldb, req, 0); /* use default timeout */
 441
 442         ret = ldb_next_request(module, req);
 443
 444         if (ret == LDB_SUCCESS) {
 445                 ret = ldb_wait(req->handle, LDB_WAIT_ALL);
 446         }
 447
 448         talloc_free(req);
 449         if (ret != LDB_SUCCESS) {
 450                 return ret;
 451         }
 452
 453         return ldb_next_init(module);
 454 }
 455
 456 static const struct ldb_module_ops ps_ops = {
 457         .name           = "paged_searches",
 458         .search         = ps_search,
 459         .wait           = ps_wait,
 460         .init_context   = ps_init
 461 };
 462
 463 int ldb_paged_searches_init(void)
 464 {
 465         return ldb_register_module(&ps_ops);
 466 }
 467