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         paged_req_control = talloc_get_type(req_control->data, struct ldb_paged_control);
  76
  77         if (!rep_control || !paged_rep_control) {
  78                 if (paged_req_control->cookie) {
  79                         /* something wrong here - why give us a control back befre, but not one now? */
  80                         ldb_set_errstring(ldb, "paged_searches:  ERROR: We got back a control from a previous page, but this time no control was returned!");
  81                         return LDB_ERR_OPERATIONS_ERROR;
  82                 } else {
  83                         /* No cookie received yet, valid to just return the full data set */
  84
  85                         /* we are done */
  86                         ac->pending = false;
  87                         return LDB_SUCCESS;
  88                 }
  89         }
  90
  91         if (paged_rep_control->cookie_len == 0) {
  92                 /* we are done */
  93                 ac->pending = false;
  94                 return LDB_SUCCESS;
  95         }
  96
  97         /* more processing required */
  98         /* let's fill in the request control with the new cookie */
  99         /* if there's a reply control we must find a request
 100          * control matching it */
 101
 102         if (paged_req_control->cookie) {
 103                 talloc_free(paged_req_control->cookie);
 104         }
 105
 106         paged_req_control->cookie = talloc_memdup(req_control,
 107                                                   paged_rep_control->cookie,
 108                                                   paged_rep_control->cookie_len);
 109         paged_req_control->cookie_len = paged_rep_control->cookie_len;
 110
 111         ac->pending = true;
 112         return LDB_SUCCESS;
 113 }
 114
 115 static int store_referral(struct ps_context *ac, char *referral)
 116 {
 117         ac->saved_referrals = talloc_realloc(ac, ac->saved_referrals, char *, ac->num_referrals + 2);
 118         if (!ac->saved_referrals) {
 119                 return LDB_ERR_OPERATIONS_ERROR;
 120         }
 121
 122         ac->saved_referrals[ac->num_referrals] = talloc_strdup(ac->saved_referrals, referral);
 123         if (!ac->saved_referrals[ac->num_referrals]) {
 124                 return LDB_ERR_OPERATIONS_ERROR;
 125         }
 126
 127         ac->num_referrals++;
 128         ac->saved_referrals[ac->num_referrals] = NULL;
 129
 130         return LDB_SUCCESS;
 131 }
 132
 133 static int send_referrals(struct ps_context *ac)
 134 {
 135         struct ldb_reply *ares;
 136         int ret;
 137         unsigned int i;
 138
 139         for (i = 0; i < ac->num_referrals; i++) {
 140                 ares = talloc_zero(ac->req, struct ldb_reply);
 141                 if (!ares) {
 142                         return LDB_ERR_OPERATIONS_ERROR;
 143                 }
 144
 145                 ares->type = LDB_REPLY_REFERRAL;
 146                 ares->referral = ac->saved_referrals[i];
 147
 148                 ret = ldb_module_send_referral(ac->req, ares->referral);
 149                 if (ret != LDB_SUCCESS) {
 150                         return ret;
 151                 }
 152         }
 153
 154         return LDB_SUCCESS;
 155 }
 156
 157 static int ps_callback(struct ldb_request *req, struct ldb_reply *ares)
 158 {
 159         struct ps_context *ac;
 160         int ret;
 161
 162         ac = talloc_get_type(req->context, struct ps_context);
 163
 164         if (!ares) {
 165                 return ldb_module_done(ac->req, NULL, NULL,
 166                                         LDB_ERR_OPERATIONS_ERROR);
 167         }
 168         if (ares->error != LDB_SUCCESS) {
 169                 return ldb_module_done(ac->req, ares->controls,
 170                                         ares->response, ares->error);
 171         }
 172
 173         switch (ares->type) {
 174         case LDB_REPLY_ENTRY:
 175                 ret = ldb_module_send_entry(ac->req, ares->message, ares->controls);
 176                 if (ret != LDB_SUCCESS) {
 177                         return ldb_module_done(ac->req, NULL, NULL, ret);
 178                 }
 179                 break;
 180
 181         case LDB_REPLY_REFERRAL:
 182                 ret = store_referral(ac, ares->referral);
 183                 if (ret != LDB_SUCCESS) {
 184                         return ldb_module_done(ac->req, NULL, NULL, ret);
 185                 }
 186                 break;
 187
 188         case LDB_REPLY_DONE:
 189
 190                 ret = check_ps_continuation(ac, req, ares);
 191                 if (ret != LDB_SUCCESS) {
 192                         return ldb_module_done(ac->req, NULL, NULL, ret);
 193                 }
 194
 195                 if (ac->pending) {
 196
 197                         ret = ldb_next_request(ac->module, ac->down_req);
 198
 199                         if (ret != LDB_SUCCESS) {
 200                                 return ldb_module_done(ac->req,
 201                                                         NULL, NULL, ret);
 202                         }
 203
 204                 } else {
 205
 206                         /* send referrals */
 207                         ret = send_referrals(ac);
 208                         if (ret != LDB_SUCCESS) {
 209                                 return ldb_module_done(ac->req,
 210                                                         NULL, NULL, ret);
 211                         }
 212
 213                         /* send REPLY_DONE */
 214                         return ldb_module_done(ac->req, ares->controls,
 215                                                 ares->response, LDB_SUCCESS);
 216                 }
 217                 break;
 218         }
 219
 220         talloc_free(ares);
 221         return LDB_SUCCESS;
 222 }
 223
 224 static int ps_search(struct ldb_module *module, struct ldb_request *req)
 225 {
 226         struct ldb_context *ldb;
 227         struct private_data *private_data;
 228         struct ps_context *ac;
 229         struct ldb_paged_control *control;
 230         int ret;
 231
 232         private_data = talloc_get_type(ldb_module_get_private(module), struct private_data);
 233         ldb = ldb_module_get_ctx(module);
 234
 235         /* check if paging is supported */
 236         if (!private_data || !private_data->paged_supported) {
 237                 /* do not touch this request paged controls not
 238                  * supported or we
 239                  * are just not setup yet */
 240                 return ldb_next_request(module, req);
 241         }
 242
 243         ac = talloc_zero(req, struct ps_context);
 244         if (ac == NULL) {
 245                 ldb_oom(ldb);
 246                 return LDB_ERR_OPERATIONS_ERROR;
 247         }
 248
 249         ac->module = module;
 250         ac->req = req;
 251         ac->pending = false;
 252         ac->saved_referrals = NULL;
 253         ac->num_referrals = 0;
 254
 255         ldb = ldb_module_get_ctx(ac->module);
 256
 257         control = talloc(ac, struct ldb_paged_control);
 258         if (!control) {
 259                 return LDB_ERR_OPERATIONS_ERROR;
 260         }
 261
 262         control->size = PS_DEFAULT_PAGE_SIZE;
 263         control->cookie = NULL;
 264         control->cookie_len = 0;
 265
 266         ret = ldb_build_search_req_ex(&ac->down_req, ldb, ac,
 267                                         ac->req->op.search.base,
 268                                         ac->req->op.search.scope,
 269                                         ac->req->op.search.tree,
 270                                         ac->req->op.search.attrs,
 271                                         ac->req->controls,
 272                                         ac,
 273                                         ps_callback,
 274                                         ac->req);
 275         LDB_REQ_SET_LOCATION(ac->down_req);
 276         if (ret != LDB_SUCCESS) {
 277                 return ret;
 278         }
 279
 280         ret = ldb_request_add_control(ac->down_req, LDB_CONTROL_PAGED_RESULTS_OID,
 281                                       true, control);
 282         if (ret != LDB_SUCCESS) {
 283                 return ret;
 284         }
 285
 286         talloc_steal(ac->down_req, control);
 287
 288         return ldb_next_request(ac->module, ac->down_req);
 289 }
 290
 291 static int check_supported_paged(struct ldb_request *req,
 292                                  struct ldb_reply *ares)
 293 {
 294         struct private_data *data;
 295
 296         data = talloc_get_type(req->context, struct private_data);
 297
 298         if (!ares) {
 299                 return ldb_request_done(req, LDB_ERR_OPERATIONS_ERROR);
 300         }
 301         if (ares->error != LDB_SUCCESS) {
 302                 return ldb_request_done(req, LDB_ERR_OPERATIONS_ERROR);
 303         }
 304
 305         switch (ares->type) {
 306         case LDB_REPLY_ENTRY:
 307                 if (ldb_msg_check_string_attribute(ares->message,
 308                                                    "supportedControl",
 309                                                    LDB_CONTROL_PAGED_RESULTS_OID)) {
 310                         data->paged_supported = true;
 311                 }
 312                 break;
 313
 314         case LDB_REPLY_REFERRAL:
 315                 /* ignore */
 316                 break;
 317
 318         case LDB_REPLY_DONE:
 319                 return ldb_request_done(req, LDB_SUCCESS);
 320         }
 321
 322         talloc_free(ares);
 323         return LDB_SUCCESS;
 324 }
 325
 326 static int ps_init(struct ldb_module *module)
 327 {
 328         struct ldb_context *ldb;
 329         static const char *attrs[] = { "supportedControl", NULL };
 330         struct private_data *data;
 331         struct ldb_dn *base;
 332         int ret;
 333         struct ldb_request *req;
 334
 335         ldb = ldb_module_get_ctx(module);
 336
 337         data = talloc(module, struct private_data);
 338         if (data == NULL) {
 339                 ldb_oom(ldb);
 340                 return LDB_ERR_OPERATIONS_ERROR;
 341         }
 342         data->paged_supported = false;
 343
 344         ldb_module_set_private(module, data);
 345
 346         base = ldb_dn_new(module, ldb, "");
 347         if (base == NULL) {
 348                 ldb_oom(ldb);
 349                 return LDB_ERR_OPERATIONS_ERROR;
 350         }
 351         ret = ldb_build_search_req(&req, ldb, module,
 352                                    base, LDB_SCOPE_BASE,
 353                                    "(objectClass=*)",
 354                                    attrs, NULL,
 355                                    data, check_supported_paged,
 356                                    NULL);
 357         LDB_REQ_SET_LOCATION(req);
 358         if (ret != LDB_SUCCESS) {
 359                 return ret;
 360         }
 361
 362         ret = ldb_next_request(module, req);
 363         if (ret == LDB_SUCCESS) {
 364                 ret = ldb_wait(req->handle, LDB_WAIT_ALL);
 365         }
 366         if (ret != LDB_SUCCESS) {
 367                 return ret;
 368         }
 369
 370         talloc_free(base);
 371         talloc_free(req);
 372
 373         return ldb_next_init(module);
 374 }
 375
 376 static const struct ldb_module_ops ldb_paged_searches_module_ops = {
 377         .name           = "paged_searches",
 378         .search         = ps_search,
 379         .init_context   = ps_init
 380 };
 381
 382 int ldb_paged_searches_init(const char *version)
 383 {
 384         LDB_MODULE_CHECK_VERSION(version);
 385         return ldb_register_module(&ldb_paged_searches_module_ops);
 386 }