lib/ldb/modules/paged_searches.c

   1 /*
   2    ldb database library
   3
   4    Copyright (C) Simo Sorce  2005-2008
   5    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2009
   6
   7      ** NOTE! The following LGPL license applies to the ldb
   8      ** library. This does NOT imply that all of Samba is released
   9      ** under the LGPL
  10
  11    This library is free software; you can redistribute it and/or
  12    modify it under the terms of the GNU Lesser General Public
  13    License as published by the Free Software Foundation; either
  14    version 3 of the License, or (at your option) any later version.
  15
  16    This library is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19    Lesser General Public License for more details.
  20
  21    You should have received a copy of the GNU Lesser General Public
  22    License along with this library; if not, see <http://www.gnu.org/licenses/>.
  23 */
  24
  25 /*
  26  *  Name: paged_searches
  27  *
  28  *  Component: ldb paged searches module
  29  *
  30  *  Description: this module detects if the remote ldap server supports
  31  *               paged results and use them to transparently access all objects
  32  *
  33  *  Author: Simo Sorce
  34  */
  35
  36 #include "replace.h"
  37 #include "system/filesys.h"
  38 #include "system/time.h"
  39 #include "ldb_module.h"
  40
  41 #define PS_DEFAULT_PAGE_SIZE 500
  42 /* 500 objects per query seem to be a decent compromise
  43  * the default AD limit per request is 1000 entries */
  44
  45 struct private_data {
  46
  47         bool paged_supported;
  48 };
  49
  50 struct ps_context {
  51         struct ldb_module *module;
  52         struct ldb_request *req;
  53
  54         bool pending;
  55
  56         char **saved_referrals;
  57         unsigned int num_referrals;
  58
  59         struct ldb_request *down_req;
  60 };
  61
  62 static int check_ps_continuation(struct ps_context *ac, struct ldb_request *req, struct ldb_reply *ares)
  63 {
  64         struct ldb_context *ldb;
  65         struct ldb_control *rep_control, *req_control;
  66         struct ldb_paged_control *paged_rep_control = NULL, *paged_req_control = NULL;
  67         ldb = ldb_module_get_ctx(ac->module);
  68
  69         rep_control = ldb_reply_get_control(ares, LDB_CONTROL_PAGED_RESULTS_OID);
  70         if (rep_control) {
  71                 paged_rep_control = talloc_get_type(rep_control->data, struct ldb_paged_control);
  72         }
  73
  74         req_control = ldb_request_get_control(req, LDB_CONTROL_PAGED_RESULTS_OID);
  75         if (req_control == NULL || req_control->data == NULL) {
  76                 ldb_set_errstring(ldb, "paged_searches: control is missing or malformed");
  77                 return LDB_ERR_OPERATIONS_ERROR;
  78         }
  79
  80         paged_req_control = talloc_get_type(req_control->data, struct ldb_paged_control);
  81
  82         if (!rep_control || !paged_rep_control) {
  83                 if (paged_req_control->cookie) {
  84                         /* something wrong here - why give us a control back befre, but not one now? */
  85                         ldb_set_errstring(ldb, "paged_searches:  ERROR: We got back a control from a previous page, but this time no control was returned!");
  86                         return LDB_ERR_OPERATIONS_ERROR;
  87                 } else {
  88                         /* No cookie received yet, valid to just return the full data set */
  89
  90                         /* we are done */
  91                         ac->pending = false;
  92                         return LDB_SUCCESS;
  93                 }
  94         }
  95
  96         if (paged_rep_control->cookie_len == 0) {
  97                 /* we are done */
  98                 ac->pending = false;
  99                 return LDB_SUCCESS;
 100         }
 101
 102         /* more processing required */
 103         /* let's fill in the request control with the new cookie */
 104         /* if there's a reply control we must find a request
 105          * control matching it */
 106
 107         if (paged_req_control->cookie) {
 108                 talloc_free(paged_req_control->cookie);
 109         }
 110
 111         paged_req_control->cookie = talloc_memdup(req_control,
 112                                                   paged_rep_control->cookie,
 113                                                   paged_rep_control->cookie_len);
 114         paged_req_control->cookie_len = paged_rep_control->cookie_len;
 115
 116         ac->pending = true;
 117         return LDB_SUCCESS;
 118 }
 119
 120 static int store_referral(struct ps_context *ac, char *referral)
 121 {
 122         ac->saved_referrals = talloc_realloc(ac, ac->saved_referrals, char *, ac->num_referrals + 2);
 123         if (!ac->saved_referrals) {
 124                 return LDB_ERR_OPERATIONS_ERROR;
 125         }
 126
 127         ac->saved_referrals[ac->num_referrals] = talloc_strdup(ac->saved_referrals, referral);
 128         if (!ac->saved_referrals[ac->num_referrals]) {
 129                 return LDB_ERR_OPERATIONS_ERROR;
 130         }
 131
 132         ac->num_referrals++;
 133         ac->saved_referrals[ac->num_referrals] = NULL;
 134
 135         return LDB_SUCCESS;
 136 }
 137
 138 static int send_referrals(struct ps_context *ac)
 139 {
 140         struct ldb_reply *ares;
 141         int ret;
 142         unsigned int i;
 143
 144         for (i = 0; i < ac->num_referrals; i++) {
 145                 ares = talloc_zero(ac->req, struct ldb_reply);
 146                 if (!ares) {
 147                         return LDB_ERR_OPERATIONS_ERROR;
 148                 }
 149
 150                 ares->type = LDB_REPLY_REFERRAL;
 151                 ares->referral = ac->saved_referrals[i];
 152
 153                 ret = ldb_module_send_referral(ac->req, ares->referral);
 154                 if (ret != LDB_SUCCESS) {
 155                         return ret;
 156                 }
 157         }
 158
 159         return LDB_SUCCESS;
 160 }
 161
 162 static int ps_callback(struct ldb_request *req, struct ldb_reply *ares)
 163 {
 164         struct ps_context *ac;
 165         int ret;
 166
 167         ac = talloc_get_type(req->context, struct ps_context);
 168
 169         if (!ares) {
 170                 return ldb_module_done(ac->req, NULL, NULL,
 171                                         LDB_ERR_OPERATIONS_ERROR);
 172         }
 173         if (ares->error != LDB_SUCCESS) {
 174                 return ldb_module_done(ac->req, ares->controls,
 175                                         ares->response, ares->error);
 176         }
 177
 178         switch (ares->type) {
 179         case LDB_REPLY_ENTRY:
 180                 ret = ldb_module_send_entry(ac->req, ares->message, ares->controls);
 181                 if (ret != LDB_SUCCESS) {
 182                         return ldb_module_done(ac->req, NULL, NULL, ret);
 183                 }
 184                 break;
 185
 186         case LDB_REPLY_REFERRAL:
 187                 ret = store_referral(ac, ares->referral);
 188                 if (ret != LDB_SUCCESS) {
 189                         return ldb_module_done(ac->req, NULL, NULL, ret);
 190                 }
 191                 break;
 192
 193         case LDB_REPLY_DONE:
 194
 195                 ret = check_ps_continuation(ac, req, ares);
 196                 if (ret != LDB_SUCCESS) {
 197                         return ldb_module_done(ac->req, NULL, NULL, ret);
 198                 }
 199
 200                 if (ac->pending) {
 201
 202                         ret = ldb_next_request(ac->module, ac->down_req);
 203
 204                         if (ret != LDB_SUCCESS) {
 205                                 return ldb_module_done(ac->req,
 206                                                         NULL, NULL, ret);
 207                         }
 208
 209                 } else {
 210
 211                         /* send referrals */
 212                         ret = send_referrals(ac);
 213                         if (ret != LDB_SUCCESS) {
 214                                 return ldb_module_done(ac->req,
 215                                                         NULL, NULL, ret);
 216                         }
 217
 218                         /* send REPLY_DONE */
 219                         return ldb_module_done(ac->req, ares->controls,
 220                                                 ares->response, LDB_SUCCESS);
 221                 }
 222                 break;
 223         }
 224
 225         talloc_free(ares);
 226         return LDB_SUCCESS;
 227 }
 228
 229 static int ps_search(struct ldb_module *module, struct ldb_request *req)
 230 {
 231         struct ldb_context *ldb;
 232         struct private_data *private_data;
 233         struct ps_context *ac;
 234         struct ldb_paged_control *control;
 235         int ret;
 236
 237         private_data = talloc_get_type(ldb_module_get_private(module), struct private_data);
 238         ldb = ldb_module_get_ctx(module);
 239
 240         /* check if paging is supported */
 241         if (!private_data || !private_data->paged_supported) {
 242                 /* do not touch this request paged controls not
 243                  * supported or we
 244                  * are just not setup yet */
 245                 return ldb_next_request(module, req);
 246         }
 247
 248         ac = talloc_zero(req, struct ps_context);
 249         if (ac == NULL) {
 250                 ldb_oom(ldb);
 251                 return LDB_ERR_OPERATIONS_ERROR;
 252         }
 253
 254         ac->module = module;
 255         ac->req = req;
 256         ac->pending = false;
 257         ac->saved_referrals = NULL;
 258         ac->num_referrals = 0;
 259
 260         ldb = ldb_module_get_ctx(ac->module);
 261
 262         control = talloc(ac, struct ldb_paged_control);
 263         if (!control) {
 264                 return LDB_ERR_OPERATIONS_ERROR;
 265         }
 266
 267         control->size = PS_DEFAULT_PAGE_SIZE;
 268         control->cookie = NULL;
 269         control->cookie_len = 0;
 270
 271         ret = ldb_build_search_req_ex(&ac->down_req, ldb, ac,
 272                                         ac->req->op.search.base,
 273                                         ac->req->op.search.scope,
 274                                         ac->req->op.search.tree,
 275                                         ac->req->op.search.attrs,
 276                                         ac->req->controls,
 277                                         ac,
 278                                         ps_callback,
 279                                         ac->req);
 280         LDB_REQ_SET_LOCATION(ac->down_req);
 281         if (ret != LDB_SUCCESS) {
 282                 return ret;
 283         }
 284
 285         ret = ldb_request_add_control(ac->down_req, LDB_CONTROL_PAGED_RESULTS_OID,
 286                                       true, control);
 287         if (ret != LDB_SUCCESS) {
 288                 return ret;
 289         }
 290
 291         talloc_steal(ac->down_req, control);
 292
 293         return ldb_next_request(ac->module, ac->down_req);
 294 }
 295
 296 static int check_supported_paged(struct ldb_request *req,
 297                                  struct ldb_reply *ares)
 298 {
 299         struct private_data *data;
 300
 301         data = talloc_get_type(req->context, struct private_data);
 302
 303         if (!ares) {
 304                 return ldb_request_done(req, LDB_ERR_OPERATIONS_ERROR);
 305         }
 306         if (ares->error != LDB_SUCCESS) {
 307                 return ldb_request_done(req, LDB_ERR_OPERATIONS_ERROR);
 308         }
 309
 310         switch (ares->type) {
 311         case LDB_REPLY_ENTRY:
 312                 if (ldb_msg_check_string_attribute(ares->message,
 313                                                    "supportedControl",
 314                                                    LDB_CONTROL_PAGED_RESULTS_OID)) {
 315                         data->paged_supported = true;
 316                 }
 317                 break;
 318
 319         case LDB_REPLY_REFERRAL:
 320                 /* ignore */
 321                 break;
 322
 323         case LDB_REPLY_DONE:
 324                 return ldb_request_done(req, LDB_SUCCESS);
 325         }
 326
 327         talloc_free(ares);
 328         return LDB_SUCCESS;
 329 }
 330
 331 static int ps_init(struct ldb_module *module)
 332 {
 333         struct ldb_context *ldb;
 334         static const char *attrs[] = { "supportedControl", NULL };
 335         struct private_data *data;
 336         struct ldb_dn *base;
 337         int ret;
 338         struct ldb_request *req;
 339
 340         ldb = ldb_module_get_ctx(module);
 341
 342         data = talloc(module, struct private_data);
 343         if (data == NULL) {
 344                 ldb_oom(ldb);
 345                 return LDB_ERR_OPERATIONS_ERROR;
 346         }
 347         data->paged_supported = false;
 348
 349         ldb_module_set_private(module, data);
 350
 351         base = ldb_dn_new(module, ldb, "");
 352         if (base == NULL) {
 353                 ldb_oom(ldb);
 354                 return LDB_ERR_OPERATIONS_ERROR;
 355         }
 356         ret = ldb_build_search_req(&req, ldb, module,
 357                                    base, LDB_SCOPE_BASE,
 358                                    "(objectClass=*)",
 359                                    attrs, NULL,
 360                                    data, check_supported_paged,
 361                                    NULL);
 362         LDB_REQ_SET_LOCATION(req);
 363         if (ret != LDB_SUCCESS) {
 364                 return ret;
 365         }
 366
 367         ret = ldb_next_request(module, req);
 368         if (ret == LDB_SUCCESS) {
 369                 ret = ldb_wait(req->handle, LDB_WAIT_ALL);
 370         }
 371         if (ret != LDB_SUCCESS) {
 372                 return ret;
 373         }
 374
 375         talloc_free(base);
 376         talloc_free(req);
 377
 378         return ldb_next_init(module);
 379 }
 380
 381 static const struct ldb_module_ops ldb_paged_searches_module_ops = {
 382         .name           = "paged_searches",
 383         .search         = ps_search,
 384         .init_context   = ps_init
 385 };
 386
 387 int ldb_paged_searches_init(const char *version)
 388 {
 389         LDB_MODULE_CHECK_VERSION(version);
 390         return ldb_register_module(&ldb_paged_searches_module_ops);
 391 }