source4/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 "includes.h"
  37 #include "ldb_module.h"
  38
  39 #define PS_DEFAULT_PAGE_SIZE 500
  40 /* 500 objects per query seem to be a decent compromise
  41  * the default AD limit per request is 1000 entries */
  42
  43 struct private_data {
  44
  45         bool paged_supported;
  46 };
  47
  48 struct ps_context {
  49         struct ldb_module *module;
  50         struct ldb_request *req;
  51
  52         bool pending;
  53
  54         char **saved_referrals;
  55         unsigned int num_referrals;
  56
  57         struct ldb_request *down_req;
  58 };
  59
  60 static int check_ps_continuation(struct ps_context *ac, struct ldb_request *req, struct ldb_reply *ares)
  61 {
  62         struct ldb_context *ldb;
  63         struct ldb_control *rep_control, *req_control;
  64         struct ldb_paged_control *paged_rep_control = NULL, *paged_req_control = NULL;
  65         ldb = ldb_module_get_ctx(ac->module);
  66
  67         rep_control = ldb_reply_get_control(ares, LDB_CONTROL_PAGED_RESULTS_OID);
  68         if (rep_control) {
  69                 paged_rep_control = talloc_get_type(rep_control->data, struct ldb_paged_control);
  70         }
  71
  72         req_control = ldb_request_get_control(req, LDB_CONTROL_PAGED_RESULTS_OID);
  73         paged_req_control = talloc_get_type(req_control->data, struct ldb_paged_control);
  74
  75         if (!rep_control || !paged_rep_control) {
  76                 if (paged_req_control->cookie) {
  77                         /* something wrong here - why give us a control back befre, but not one now? */
  78                         ldb_set_errstring(ldb, "paged_searches:  ERROR: We got back a control from a previous page, but this time no control was returned!");
  79                         return LDB_ERR_OPERATIONS_ERROR;
  80                 } else {
  81                         /* No cookie received yet, valid to just return the full data set */
  82
  83                         /* we are done */
  84                         ac->pending = false;
  85                         return LDB_SUCCESS;
  86                 }
  87         }
  88
  89         if (paged_rep_control->cookie_len == 0) {
  90                 /* we are done */
  91                 ac->pending = false;
  92                 return LDB_SUCCESS;
  93         }
  94
  95         /* more processing required */
  96         /* let's fill in the request control with the new cookie */
  97         /* if there's a reply control we must find a request
  98          * control matching it */
  99
 100         if (paged_req_control->cookie) {
 101                 talloc_free(paged_req_control->cookie);
 102         }
 103
 104         paged_req_control->cookie = talloc_memdup(req_control,
 105                                                   paged_rep_control->cookie,
 106                                                   paged_rep_control->cookie_len);
 107         paged_req_control->cookie_len = paged_rep_control->cookie_len;
 108
 109         ac->pending = true;
 110         return LDB_SUCCESS;
 111 }
 112
 113 static int store_referral(struct ps_context *ac, char *referral)
 114 {
 115         ac->saved_referrals = talloc_realloc(ac, ac->saved_referrals, char *, ac->num_referrals + 2);
 116         if (!ac->saved_referrals) {
 117                 return LDB_ERR_OPERATIONS_ERROR;
 118         }
 119
 120         ac->saved_referrals[ac->num_referrals] = talloc_strdup(ac->saved_referrals, referral);
 121         if (!ac->saved_referrals[ac->num_referrals]) {
 122                 return LDB_ERR_OPERATIONS_ERROR;
 123         }
 124
 125         ac->num_referrals++;
 126         ac->saved_referrals[ac->num_referrals] = NULL;
 127
 128         return LDB_SUCCESS;
 129 }
 130
 131 static int send_referrals(struct ps_context *ac)
 132 {
 133         struct ldb_reply *ares;
 134         int ret;
 135         unsigned int i;
 136
 137         for (i = 0; i < ac->num_referrals; i++) {
 138                 ares = talloc_zero(ac->req, struct ldb_reply);
 139                 if (!ares) {
 140                         return LDB_ERR_OPERATIONS_ERROR;
 141                 }
 142
 143                 ares->type = LDB_REPLY_REFERRAL;
 144                 ares->referral = ac->saved_referrals[i];
 145
 146                 ret = ldb_module_send_referral(ac->req, ares->referral);
 147                 if (ret != LDB_SUCCESS) {
 148                         return ret;
 149                 }
 150         }
 151
 152         return LDB_SUCCESS;
 153 }
 154
 155 static int ps_callback(struct ldb_request *req, struct ldb_reply *ares)
 156 {
 157         struct ps_context *ac;
 158         int ret;
 159
 160         ac = talloc_get_type(req->context, struct ps_context);
 161
 162         if (!ares) {
 163                 return ldb_module_done(ac->req, NULL, NULL,
 164                                         LDB_ERR_OPERATIONS_ERROR);
 165         }
 166         if (ares->error != LDB_SUCCESS) {
 167                 return ldb_module_done(ac->req, ares->controls,
 168                                         ares->response, ares->error);
 169         }
 170
 171         switch (ares->type) {
 172         case LDB_REPLY_ENTRY:
 173                 ret = ldb_module_send_entry(ac->req, ares->message, ares->controls);
 174                 if (ret != LDB_SUCCESS) {
 175                         return ldb_module_done(ac->req, NULL, NULL, ret);
 176                 }
 177                 break;
 178
 179         case LDB_REPLY_REFERRAL:
 180                 ret = store_referral(ac, ares->referral);
 181                 if (ret != LDB_SUCCESS) {
 182                         return ldb_module_done(ac->req, NULL, NULL, ret);
 183                 }
 184                 break;
 185
 186         case LDB_REPLY_DONE:
 187
 188                 ret = check_ps_continuation(ac, req, ares);
 189                 if (ret != LDB_SUCCESS) {
 190                         return ldb_module_done(ac->req, NULL, NULL, ret);
 191                 }
 192
 193                 if (ac->pending) {
 194
 195                         ret = ldb_next_request(ac->module, ac->down_req);
 196
 197                         if (ret != LDB_SUCCESS) {
 198                                 return ldb_module_done(ac->req,
 199                                                         NULL, NULL, ret);
 200                         }
 201
 202                 } else {
 203
 204                         /* send referrals */
 205                         ret = send_referrals(ac);
 206                         if (ret != LDB_SUCCESS) {
 207                                 return ldb_module_done(ac->req,
 208                                                         NULL, NULL, ret);
 209                         }
 210
 211                         /* send REPLY_DONE */
 212                         return ldb_module_done(ac->req, ares->controls,
 213                                                 ares->response, LDB_SUCCESS);
 214                 }
 215                 break;
 216         }
 217
 218         talloc_free(ares);
 219         return LDB_SUCCESS;
 220 }
 221
 222 static int ps_search(struct ldb_module *module, struct ldb_request *req)
 223 {
 224         struct ldb_context *ldb;
 225         struct private_data *private_data;
 226         struct ps_context *ac;
 227         struct ldb_paged_control *control;
 228         int ret;
 229
 230         private_data = talloc_get_type(ldb_module_get_private(module), struct private_data);
 231         ldb = ldb_module_get_ctx(module);
 232
 233         /* check if paging is supported */
 234         if (!private_data || !private_data->paged_supported) {
 235                 /* do not touch this request paged controls not
 236                  * supported or we
 237                  * are just not setup yet */
 238                 return ldb_next_request(module, req);
 239         }
 240
 241         ac = talloc_zero(req, struct ps_context);
 242         if (ac == NULL) {
 243                 ldb_oom(ldb);
 244                 return LDB_ERR_OPERATIONS_ERROR;
 245         }
 246
 247         ac->module = module;
 248         ac->req = req;
 249         ac->pending = false;
 250         ac->saved_referrals = NULL;
 251         ac->num_referrals = 0;
 252
 253         ldb = ldb_module_get_ctx(ac->module);
 254
 255         control = talloc(ac, struct ldb_paged_control);
 256         if (!control) {
 257                 return LDB_ERR_OPERATIONS_ERROR;
 258         }
 259
 260         control->size = PS_DEFAULT_PAGE_SIZE;
 261         control->cookie = NULL;
 262         control->cookie_len = 0;
 263
 264         ret = ldb_build_search_req_ex(&ac->down_req, ldb, ac,
 265                                         ac->req->op.search.base,
 266                                         ac->req->op.search.scope,
 267                                         ac->req->op.search.tree,
 268                                         ac->req->op.search.attrs,
 269                                         ac->req->controls,
 270                                         ac,
 271                                         ps_callback,
 272                                         ac->req);
 273         if (ret != LDB_SUCCESS) {
 274                 return ret;
 275         }
 276
 277         ret = ldb_request_add_control(ac->down_req, LDB_CONTROL_PAGED_RESULTS_OID,
 278                                       true, control);
 279         if (ret != LDB_SUCCESS) {
 280                 return ret;
 281         }
 282
 283         talloc_steal(ac->down_req, control);
 284
 285         return ldb_next_request(ac->module, ac->down_req);
 286 }
 287
 288 static int check_supported_paged(struct ldb_request *req,
 289                                  struct ldb_reply *ares)
 290 {
 291         struct private_data *data;
 292
 293         data = talloc_get_type(req->context, struct private_data);
 294
 295         if (!ares) {
 296                 return ldb_request_done(req, LDB_ERR_OPERATIONS_ERROR);
 297         }
 298         if (ares->error != LDB_SUCCESS) {
 299                 return ldb_request_done(req, LDB_ERR_OPERATIONS_ERROR);
 300         }
 301
 302         switch (ares->type) {
 303         case LDB_REPLY_ENTRY:
 304                 if (ldb_msg_check_string_attribute(ares->message,
 305                                                    "supportedControl",
 306                                                    LDB_CONTROL_PAGED_RESULTS_OID)) {
 307                         data->paged_supported = true;
 308                 }
 309                 break;
 310
 311         case LDB_REPLY_REFERRAL:
 312                 /* ignore */
 313                 break;
 314
 315         case LDB_REPLY_DONE:
 316                 return ldb_request_done(req, LDB_SUCCESS);
 317         }
 318
 319         talloc_free(ares);
 320         return LDB_SUCCESS;
 321 }
 322
 323 static int ps_init(struct ldb_module *module)
 324 {
 325         struct ldb_context *ldb;
 326         static const char *attrs[] = { "supportedControl", NULL };
 327         struct private_data *data;
 328         struct ldb_dn *base;
 329         int ret;
 330         struct ldb_request *req;
 331
 332         ldb = ldb_module_get_ctx(module);
 333
 334         data = talloc(module, struct private_data);
 335         if (data == NULL) {
 336                 ldb_oom(ldb);
 337                 return LDB_ERR_OPERATIONS_ERROR;
 338         }
 339         data->paged_supported = false;
 340
 341         ldb_module_set_private(module, data);
 342
 343         base = ldb_dn_new(module, ldb, "");
 344         if (base == NULL) {
 345                 ldb_oom(ldb);
 346                 return LDB_ERR_OPERATIONS_ERROR;
 347         }
 348         ret = ldb_build_search_req(&req, ldb, module,
 349                                    base, LDB_SCOPE_BASE,
 350                                    "(objectClass=*)",
 351                                    attrs, NULL,
 352                                    data, check_supported_paged,
 353                                    NULL);
 354         if (ret != LDB_SUCCESS) {
 355                 return ret;
 356         }
 357
 358         ret = ldb_next_request(module, req);
 359         if (ret == LDB_SUCCESS) {
 360                 ret = ldb_wait(req->handle, LDB_WAIT_ALL);
 361         }
 362         if (ret != LDB_SUCCESS) {
 363                 return ret;
 364         }
 365
 366         talloc_free(base);
 367         talloc_free(req);
 368
 369         return ldb_next_init(module);
 370 }
 371
 372 _PUBLIC_ const struct ldb_module_ops ldb_paged_searches_module_ops = {
 373         .name           = "paged_searches",
 374         .search         = ps_search,
 375         .init_context   = ps_init
 376 };