source4/lib/ldb/modules/paged_searches.c

   1 /*
   2    ldb database library
   3
   4    Copyright (C) Simo Sorce  2005-2008
   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_module.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         struct ldb_request *req;
  50
  51         bool pending;
  52
  53         char **saved_referrals;
  54         int num_referrals;
  55 };
  56
  57 static int check_ps_continuation(struct ldb_request *req, struct ldb_reply *ares)
  58 {
  59         struct ps_context *ac;
  60         struct ldb_paged_control *rep_control, *req_control;
  61
  62         ac = talloc_get_type(req->context, struct ps_context);
  63
  64         /* look up our paged control */
  65         if (!ares->controls || strcmp(LDB_CONTROL_PAGED_RESULTS_OID, ares->controls[0]->oid) != 0) {
  66                 /* something wrong here */
  67                 return LDB_ERR_OPERATIONS_ERROR;
  68         }
  69
  70         rep_control = talloc_get_type(ares->controls[0]->data, struct ldb_paged_control);
  71         if (rep_control->cookie_len == 0) {
  72                 /* we are done */
  73                 ac->pending = false;
  74                 return LDB_SUCCESS;
  75         }
  76
  77         /* more processing required */
  78         /* let's fill in the request control with the new cookie */
  79         /* if there's a reply control we must find a request
  80          * control matching it */
  81
  82         if (strcmp(LDB_CONTROL_PAGED_RESULTS_OID, req->controls[0]->oid) != 0) {
  83                 /* something wrong here */
  84                 return LDB_ERR_OPERATIONS_ERROR;
  85         }
  86
  87         req_control = talloc_get_type(req->controls[0]->data, struct ldb_paged_control);
  88
  89         if (req_control->cookie) {
  90                 talloc_free(req_control->cookie);
  91         }
  92
  93         req_control->cookie = talloc_memdup(req_control,
  94                                             rep_control->cookie,
  95                                             rep_control->cookie_len);
  96         req_control->cookie_len = rep_control->cookie_len;
  97
  98         ac->pending = true;
  99         return LDB_SUCCESS;
 100 }
 101
 102 static int store_referral(struct ps_context *ac, char *referral)
 103 {
 104         ac->saved_referrals = talloc_realloc(ac, ac->saved_referrals, char *, ac->num_referrals + 2);
 105         if (!ac->saved_referrals) {
 106                 return LDB_ERR_OPERATIONS_ERROR;
 107         }
 108
 109         ac->saved_referrals[ac->num_referrals] = talloc_strdup(ac->saved_referrals, referral);
 110         if (!ac->saved_referrals[ac->num_referrals]) {
 111                 return LDB_ERR_OPERATIONS_ERROR;
 112         }
 113
 114         ac->num_referrals++;
 115         ac->saved_referrals[ac->num_referrals] = NULL;
 116
 117         return LDB_SUCCESS;
 118 }
 119
 120 static int send_referrals(struct ps_context *ac)
 121 {
 122         struct ldb_reply *ares;
 123         int ret;
 124         int i;
 125
 126         for (i = 0; i < ac->num_referrals; i++) {
 127                 ares = talloc_zero(ac->req, struct ldb_reply);
 128                 if (!ares) {
 129                         return LDB_ERR_OPERATIONS_ERROR;
 130                 }
 131
 132                 ares->type = LDB_REPLY_REFERRAL;
 133                 ares->referral = ac->saved_referrals[i];
 134
 135                 ret = ldb_module_send_referral(ac->req, ares->referral);
 136                 if (ret != LDB_SUCCESS) {
 137                         return ret;
 138                 }
 139         }
 140
 141         return LDB_SUCCESS;
 142 }
 143
 144 static int ps_next_request(struct ps_context *ac);
 145
 146 static int ps_callback(struct ldb_request *req, struct ldb_reply *ares)
 147 {
 148         struct ps_context *ac;
 149         int ret;
 150
 151         ac = talloc_get_type(req->context, struct ps_context);
 152
 153         if (!ares) {
 154                 return ldb_module_done(ac->req, NULL, NULL,
 155                                         LDB_ERR_OPERATIONS_ERROR);
 156         }
 157         if (ares->error != LDB_SUCCESS) {
 158                 return ldb_module_done(ac->req, ares->controls,
 159                                         ares->response, ares->error);
 160         }
 161
 162         switch (ares->type) {
 163         case LDB_REPLY_ENTRY:
 164                 ret = ldb_module_send_entry(ac->req, ares->message, ares->controls);
 165                 if (ret != LDB_SUCCESS) {
 166                         return ldb_module_done(ac->req, NULL, NULL, ret);
 167                 }
 168                 break;
 169
 170         case LDB_REPLY_REFERRAL:
 171                 ret = store_referral(ac, ares->referral);
 172                 if (ret != LDB_SUCCESS) {
 173                         return ldb_module_done(ac->req, NULL, NULL, ret);
 174                 }
 175                 break;
 176
 177         case LDB_REPLY_DONE:
 178
 179                 ret = check_ps_continuation(req, ares);
 180                 if (ret != LDB_SUCCESS) {
 181                         return ldb_module_done(ac->req, NULL, NULL, ret);
 182                 }
 183
 184                 if (ac->pending) {
 185
 186                         ret = ps_next_request(ac);
 187                         if (ret != LDB_SUCCESS) {
 188                                 return ldb_module_done(ac->req,
 189                                                         NULL, NULL, ret);
 190                         }
 191
 192                 } else {
 193
 194                         /* send referrals */
 195                         ret = send_referrals(ac);
 196                         if (ret != LDB_SUCCESS) {
 197                                 return ldb_module_done(ac->req,
 198                                                         NULL, NULL, ret);
 199                         }
 200
 201                         /* send REPLY_DONE */
 202                         return ldb_module_done(ac->req, ares->controls,
 203                                                 ares->response, LDB_SUCCESS);
 204                 }
 205                 break;
 206         }
 207
 208         talloc_free(ares);
 209         return LDB_SUCCESS;
 210 }
 211
 212 static int ps_search(struct ldb_module *module, struct ldb_request *req)
 213 {
 214         struct ldb_context *ldb;
 215         struct private_data *private_data;
 216         struct ps_context *ac;
 217
 218         private_data = talloc_get_type(ldb_module_get_private(module), struct private_data);
 219         ldb = ldb_module_get_ctx(module);
 220
 221         /* check if paging is supported and if there is a any control */
 222         if (!private_data || !private_data->paged_supported || req->controls) {
 223                 /* do not touch this request paged controls not
 224                  * supported or explicit controls have been set or we
 225                  * are just not setup yet */
 226                 return ldb_next_request(module, req);
 227         }
 228
 229         ac = talloc_zero(req, struct ps_context);
 230         if (ac == NULL) {
 231                 ldb_oom(ldb);
 232                 return LDB_ERR_OPERATIONS_ERROR;
 233         }
 234
 235         ac->module = module;
 236         ac->req = req;
 237         ac->pending = false;
 238         ac->saved_referrals = NULL;
 239         ac->num_referrals = 0;
 240
 241         return ps_next_request(ac);
 242 }
 243
 244 static int ps_next_request(struct ps_context *ac) {
 245
 246         struct ldb_context *ldb;
 247         struct ldb_paged_control *control;
 248         struct ldb_control **controls;
 249         struct ldb_request *new_req;
 250         int ret;
 251
 252         ldb = ldb_module_get_ctx(ac->module);
 253
 254         controls = talloc_array(ac, struct ldb_control *, 2);
 255         if (!controls) {
 256                 return LDB_ERR_OPERATIONS_ERROR;
 257         }
 258
 259         controls[0] = talloc(controls, struct ldb_control);
 260         if (!controls[0]) {
 261                 return LDB_ERR_OPERATIONS_ERROR;
 262         }
 263
 264         control = talloc(controls[0], struct ldb_paged_control);
 265         if (!control) {
 266                 return LDB_ERR_OPERATIONS_ERROR;
 267         }
 268
 269         control->size = PS_DEFAULT_PAGE_SIZE;
 270         control->cookie = NULL;
 271         control->cookie_len = 0;
 272
 273         controls[0]->oid = LDB_CONTROL_PAGED_RESULTS_OID;
 274         controls[0]->critical = 1;
 275         controls[0]->data = control;
 276         controls[1] = NULL;
 277
 278         ret = ldb_build_search_req_ex(&new_req, ldb, ac,
 279                                         ac->req->op.search.base,
 280                                         ac->req->op.search.scope,
 281                                         ac->req->op.search.tree,
 282                                         ac->req->op.search.attrs,
 283                                         controls,
 284                                         ac,
 285                                         ps_callback,
 286                                         ac->req);
 287         if (ret != LDB_SUCCESS) {
 288                 return ret;
 289         }
 290         talloc_steal(new_req, controls);
 291
 292         return ldb_next_request(ac->module, new_req);
 293 }
 294
 295 static int check_supported_paged(struct ldb_request *req,
 296                                  struct ldb_reply *ares)
 297 {
 298         struct private_data *data;
 299
 300         data = talloc_get_type(req->context, struct private_data);
 301
 302         if (!ares) {
 303                 return ldb_request_done(req, LDB_ERR_OPERATIONS_ERROR);
 304         }
 305         if (ares->error != LDB_SUCCESS) {
 306                 return ldb_request_done(req, LDB_ERR_OPERATIONS_ERROR);
 307         }
 308
 309         switch (ares->type) {
 310         case LDB_REPLY_ENTRY:
 311                 if (ldb_msg_check_string_attribute(ares->message,
 312                                                    "supportedControl",
 313                                                    LDB_CONTROL_PAGED_RESULTS_OID)) {
 314                         data->paged_supported = true;
 315                 }
 316                 break;
 317
 318         case LDB_REPLY_REFERRAL:
 319                 /* ignore */
 320                 break;
 321
 322         case LDB_REPLY_DONE:
 323                 return ldb_request_done(req, LDB_SUCCESS);
 324         }
 325
 326         talloc_free(ares);
 327         return LDB_SUCCESS;
 328 }
 329
 330 static int ps_init(struct ldb_module *module)
 331 {
 332         struct ldb_context *ldb;
 333         static const char *attrs[] = { "supportedControl", NULL };
 334         struct private_data *data;
 335         struct ldb_dn *base;
 336         int ret;
 337         struct ldb_request *req;
 338
 339         ldb = ldb_module_get_ctx(module);
 340
 341         data = talloc(module, struct private_data);
 342         if (data == NULL) {
 343                 ldb_oom(ldb);
 344                 return LDB_ERR_OPERATIONS_ERROR;
 345         }
 346         data->paged_supported = false;
 347
 348         ldb_module_set_private(module, data);
 349
 350         base = ldb_dn_new(module, ldb, "");
 351         if (base == NULL) {
 352                 ldb_oom(ldb);
 353                 return LDB_ERR_OPERATIONS_ERROR;
 354         }
 355         ret = ldb_build_search_req(&req, ldb, module,
 356                                    base, LDB_SCOPE_BASE,
 357                                    "(objectClass=*)",
 358                                    attrs, NULL,
 359                                    data, check_supported_paged,
 360                                    NULL);
 361         if (ret != LDB_SUCCESS) {
 362                 return ret;
 363         }
 364
 365         ret = ldb_next_request(module, req);
 366         if (ret == LDB_SUCCESS) {
 367                 ret = ldb_wait(req->handle, LDB_WAIT_ALL);
 368         }
 369         if (ret != LDB_SUCCESS) {
 370                 return ret;
 371         }
 372
 373         talloc_free(base);
 374         talloc_free(req);
 375
 376         return ldb_next_init(module);
 377 }
 378
 379 _PUBLIC_ const struct ldb_module_ops ldb_paged_searches_module_ops = {
 380         .name           = "paged_searches",
 381         .search         = ps_search,
 382         .init_context   = ps_init
 383 };