lib/ldb/modules/sort.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: ldb
  26  *
  27  *  Component: ldb server side sort control module
  28  *
  29  *  Description: this module sorts the results of a search
  30  *
  31  *  Author: Simo Sorce
  32  */
  33
  34 #include "replace.h"
  35 #include "system/filesys.h"
  36 #include "system/time.h"
  37 #include "ldb_module.h"
  38
  39 struct opaque {
  40         struct ldb_context *ldb;
  41         const struct ldb_attrib_handler *h;
  42         const char *attribute;
  43         int reverse;
  44         int result;
  45 };
  46
  47 struct sort_context {
  48         struct ldb_module *module;
  49
  50         const char *attributeName;
  51         const char *orderingRule;
  52         int reverse;
  53
  54         struct ldb_request *req;
  55         struct ldb_message **msgs;
  56         char **referrals;
  57         unsigned int num_msgs;
  58         unsigned int num_refs;
  59
  60         const struct ldb_schema_attribute *a;
  61         int sort_result;
  62 };
  63
  64 static int build_response(void *mem_ctx, struct ldb_control ***ctrls, int result, const char *desc)
  65 {
  66         struct ldb_control **controls;
  67         struct ldb_sort_resp_control *resp;
  68         unsigned int i;
  69
  70         if (*ctrls) {
  71                 controls = *ctrls;
  72                 for (i = 0; controls[i]; i++);
  73                 controls = talloc_realloc(mem_ctx, controls, struct ldb_control *, i + 2);
  74         } else {
  75                 i = 0;
  76                 controls = talloc_array(mem_ctx, struct ldb_control *, 2);
  77         }
  78         if (! controls )
  79                 return LDB_ERR_OPERATIONS_ERROR;
  80
  81         *ctrls = controls;
  82
  83         controls[i+1] = NULL;
  84         controls[i] = talloc(controls, struct ldb_control);
  85         if (! controls[i] )
  86                 return LDB_ERR_OPERATIONS_ERROR;
  87
  88         controls[i]->oid = LDB_CONTROL_SORT_RESP_OID;
  89         controls[i]->critical = 0;
  90
  91         resp = talloc(controls[i], struct ldb_sort_resp_control);
  92         if (! resp )
  93                 return LDB_ERR_OPERATIONS_ERROR;
  94
  95         resp->result = result;
  96         resp->attr_desc = talloc_strdup(resp, desc);
  97
  98         if (! resp->attr_desc )
  99                 return LDB_ERR_OPERATIONS_ERROR;
 100
 101         controls[i]->data = resp;
 102
 103         return LDB_SUCCESS;
 104 }
 105
 106 static int sort_compare(struct ldb_message **msg1, struct ldb_message **msg2, void *opaque)
 107 {
 108         struct sort_context *ac = talloc_get_type(opaque, struct sort_context);
 109         struct ldb_message_element *el1, *el2;
 110         struct ldb_context *ldb;
 111
 112         ldb = ldb_module_get_ctx(ac->module);
 113
 114         if (ac->sort_result != 0) {
 115                 /* an error occurred previously,
 116                  * let's exit the sorting by returning always 0 */
 117                 return 0;
 118         }
 119
 120         el1 = ldb_msg_find_element(*msg1, ac->attributeName);
 121         el2 = ldb_msg_find_element(*msg2, ac->attributeName);
 122
 123         if (!el1 && el2) {
 124                 return 1;
 125         }
 126         if (el1 && !el2) {
 127                 return -1;
 128         }
 129         if (!el1 && !el2) {
 130                 return 0;
 131         }
 132
 133         if (ac->reverse)
 134                 return ac->a->syntax->comparison_fn(ldb, ac, &el2->values[0], &el1->values[0]);
 135
 136         return ac->a->syntax->comparison_fn(ldb, ac, &el1->values[0], &el2->values[0]);
 137 }
 138
 139 static int server_sort_results(struct sort_context *ac)
 140 {
 141         struct ldb_context *ldb;
 142         struct ldb_reply *ares;
 143         unsigned int i;
 144         int ret;
 145
 146         ldb = ldb_module_get_ctx(ac->module);
 147
 148         ac->a = ldb_schema_attribute_by_name(ldb, ac->attributeName);
 149         ac->sort_result = 0;
 150
 151         LDB_TYPESAFE_QSORT(ac->msgs, ac->num_msgs, ac, sort_compare);
 152
 153         if (ac->sort_result != LDB_SUCCESS) {
 154                 return ac->sort_result;
 155         }
 156
 157         for (i = 0; i < ac->num_msgs; i++) {
 158                 ares = talloc_zero(ac, struct ldb_reply);
 159                 if (!ares) {
 160                         return LDB_ERR_OPERATIONS_ERROR;
 161                 }
 162
 163                 ares->type = LDB_REPLY_ENTRY;
 164                 ares->message = talloc_move(ares, &ac->msgs[i]);
 165
 166                 ret = ldb_module_send_entry(ac->req, ares->message, ares->controls);
 167                 if (ret != LDB_SUCCESS) {
 168                         return ret;
 169                 }
 170         }
 171
 172         for (i = 0; i < ac->num_refs; i++) {
 173                 ares = talloc_zero(ac, struct ldb_reply);
 174                 if (!ares) {
 175                         return LDB_ERR_OPERATIONS_ERROR;
 176                 }
 177
 178                 ares->type = LDB_REPLY_REFERRAL;
 179                 ares->referral = talloc_move(ares, &ac->referrals[i]);
 180
 181                 ret = ldb_module_send_referral(ac->req, ares->referral);
 182                 if (ret != LDB_SUCCESS) {
 183                         return ret;
 184                 }
 185         }
 186
 187         return LDB_SUCCESS;
 188 }
 189
 190 static int server_sort_search_callback(struct ldb_request *req, struct ldb_reply *ares)
 191 {
 192         struct sort_context *ac;
 193         struct ldb_context *ldb;
 194         int ret;
 195
 196         ac = talloc_get_type(req->context, struct sort_context);
 197         ldb = ldb_module_get_ctx(ac->module);
 198
 199         if (!ares) {
 200                 return ldb_module_done(ac->req, NULL, NULL,
 201                                         LDB_ERR_OPERATIONS_ERROR);
 202         }
 203         if (ares->error != LDB_SUCCESS) {
 204                 return ldb_module_done(ac->req, ares->controls,
 205                                         ares->response, ares->error);
 206         }
 207
 208         switch (ares->type) {
 209         case LDB_REPLY_ENTRY:
 210                 ac->msgs = talloc_realloc(ac, ac->msgs, struct ldb_message *, ac->num_msgs + 2);
 211                 if (! ac->msgs) {
 212                         talloc_free(ares);
 213                         ldb_oom(ldb);
 214                         return ldb_module_done(ac->req, NULL, NULL,
 215                                                 LDB_ERR_OPERATIONS_ERROR);
 216                 }
 217
 218                 ac->msgs[ac->num_msgs] = talloc_steal(ac->msgs, ares->message);
 219                 ac->num_msgs++;
 220                 ac->msgs[ac->num_msgs] = NULL;
 221
 222                 break;
 223
 224         case LDB_REPLY_REFERRAL:
 225                 ac->referrals = talloc_realloc(ac, ac->referrals, char *, ac->num_refs + 2);
 226                 if (! ac->referrals) {
 227                         talloc_free(ares);
 228                         ldb_oom(ldb);
 229                         return ldb_module_done(ac->req, NULL, NULL,
 230                                                 LDB_ERR_OPERATIONS_ERROR);
 231                 }
 232
 233                 ac->referrals[ac->num_refs] = talloc_steal(ac->referrals, ares->referral);
 234                 ac->num_refs++;
 235                 ac->referrals[ac->num_refs] = NULL;
 236
 237                 break;
 238
 239         case LDB_REPLY_DONE:
 240
 241                 ret = server_sort_results(ac);
 242                 return ldb_module_done(ac->req, ares->controls,
 243                                         ares->response, ret);
 244         }
 245
 246         talloc_free(ares);
 247         return LDB_SUCCESS;
 248 }
 249
 250 static int server_sort_search(struct ldb_module *module, struct ldb_request *req)
 251 {
 252         struct ldb_control *control;
 253         struct ldb_server_sort_control **sort_ctrls;
 254         struct ldb_control **saved_controls;
 255         struct ldb_control **controls;
 256         struct ldb_request *down_req;
 257         struct sort_context *ac;
 258         struct ldb_context *ldb;
 259         int ret;
 260
 261         ldb = ldb_module_get_ctx(module);
 262
 263         /* check if there's a server sort control */
 264         control = ldb_request_get_control(req, LDB_CONTROL_SERVER_SORT_OID);
 265         if (control == NULL) {
 266                 /* not found go on */
 267                 return ldb_next_request(module, req);
 268         }
 269
 270         ac = talloc_zero(req, struct sort_context);
 271         if (ac == NULL) {
 272                 ldb_oom(ldb);
 273                 return LDB_ERR_OPERATIONS_ERROR;
 274         }
 275
 276         ac->module = module;
 277         ac->req = req;
 278
 279         sort_ctrls = talloc_get_type(control->data, struct ldb_server_sort_control *);
 280         if (!sort_ctrls) {
 281                 return LDB_ERR_PROTOCOL_ERROR;
 282         }
 283
 284         /* FIXME: we do not support more than one attribute for sorting right now */
 285         /* FIXME: we need to check if the attribute type exist or return an error */
 286
 287         if (sort_ctrls[1] != NULL) {
 288                 if (control->critical) {
 289
 290                         /* callback immediately */
 291                         ret = build_response(req, &controls,
 292                                              LDB_ERR_UNWILLING_TO_PERFORM,
 293                                              "sort control is not complete yet");
 294                         if (ret != LDB_SUCCESS) {
 295                                 return ldb_module_done(req, NULL, NULL,
 296                                                     LDB_ERR_OPERATIONS_ERROR);
 297                         }
 298
 299                         return ldb_module_done(req, controls, NULL, ret);
 300                 } else {
 301                         /* just pass the call down and don't do any sorting */
 302                         return ldb_next_request(module, req);
 303                 }
 304         }
 305
 306         ac->attributeName = sort_ctrls[0]->attributeName;
 307         ac->orderingRule = sort_ctrls[0]->orderingRule;
 308         ac->reverse = sort_ctrls[0]->reverse;
 309
 310         ret = ldb_build_search_req_ex(&down_req, ldb, ac,
 311                                         req->op.search.base,
 312                                         req->op.search.scope,
 313                                         req->op.search.tree,
 314                                         req->op.search.attrs,
 315                                         req->controls,
 316                                         ac,
 317                                         server_sort_search_callback,
 318                                         req);
 319         if (ret != LDB_SUCCESS) {
 320                 return ret;
 321         }
 322
 323         /* save it locally and remove it from the list */
 324         /* we do not need to replace them later as we
 325          * are keeping the original req intact */
 326         if (!ldb_save_controls(control, down_req, &saved_controls)) {
 327                 return LDB_ERR_OPERATIONS_ERROR;
 328         }
 329
 330         return ldb_next_request(module, down_req);
 331 }
 332
 333 static int server_sort_init(struct ldb_module *module)
 334 {
 335         struct ldb_context *ldb;
 336         int ret;
 337
 338         ldb = ldb_module_get_ctx(module);
 339
 340         ret = ldb_mod_register_control(module, LDB_CONTROL_SERVER_SORT_OID);
 341         if (ret != LDB_SUCCESS) {
 342                 ldb_debug(ldb, LDB_DEBUG_WARNING,
 343                         "server_sort:"
 344                         "Unable to register control with rootdse!");
 345         }
 346
 347         return ldb_next_init(module);
 348 }
 349
 350 static const struct ldb_module_ops ldb_server_sort_module_ops = {
 351         .name              = "server_sort",
 352         .search            = server_sort_search,
 353         .init_context      = server_sort_init
 354 };
 355
 356 int ldb_server_sort_init(const char *version)
 357 {
 358         LDB_MODULE_CHECK_VERSION(version);
 359         return ldb_register_module(&ldb_server_sort_module_ops);
 360 }