source/lib/ldb/modules/paged_searches.c

   1 /*
   2    ldb database library
   3
   4    Copyright (C) Simo Sorce  2005-2006
   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 2 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, write to the Free Software
  22    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  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/include/includes.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         void *up_context;
  51         int (*up_callback)(struct ldb_context *, void *, struct ldb_reply *);
  52
  53         struct ldb_request *orig_req;
  54
  55         struct ldb_request *new_req;
  56
  57         bool pending;
  58
  59         char **saved_referrals;
  60         int num_referrals;
  61 };
  62
  63 static struct ldb_handle *init_handle(void *mem_ctx, struct ldb_module *module,
  64                                             void *context,
  65                                             int (*callback)(struct ldb_context *, void *, struct ldb_reply *))
  66 {
  67         struct ps_context *ac;
  68         struct ldb_handle *h;
  69
  70         h = talloc_zero(mem_ctx, struct ldb_handle);
  71         if (h == NULL) {
  72                 ldb_set_errstring(module->ldb, "Out of Memory");
  73                 return NULL;
  74         }
  75
  76         h->module = module;
  77
  78         ac = talloc_zero(h, struct ps_context);
  79         if (ac == NULL) {
  80                 ldb_set_errstring(module->ldb, "Out of Memory");
  81                 talloc_free(h);
  82                 return NULL;
  83         }
  84
  85         h->private_data = (void *)ac;
  86
  87         h->state = LDB_ASYNC_INIT;
  88         h->status = LDB_SUCCESS;
  89
  90         ac->module = module;
  91         ac->up_context = context;
  92         ac->up_callback = callback;
  93
  94         ac->pending = False;
  95         ac->saved_referrals = NULL;
  96         ac->num_referrals = 0;
  97
  98         return h;
  99 }
 100
 101 static int check_ps_continuation(struct ldb_reply *ares, struct ps_context *ac)
 102 {
 103         struct ldb_paged_control *rep_control, *req_control;
 104
 105         /* look up our paged control */
 106         if (!ares->controls || strcmp(LDB_CONTROL_PAGED_RESULTS_OID, ares->controls[0]->oid) != 0) {
 107                 /* something wrong here */
 108                 return LDB_ERR_OPERATIONS_ERROR;
 109         }
 110
 111         rep_control = talloc_get_type(ares->controls[0]->data, struct ldb_paged_control);
 112         if (rep_control->cookie_len == 0) {
 113                 /* we are done */
 114                 ac->pending = False;
 115                 return LDB_SUCCESS;
 116         }
 117
 118         /* more processing required */
 119         /* let's fill in the request control with the new cookie */
 120         /* if there's a reply control we must find a request
 121          * control matching it */
 122
 123         if (strcmp(LDB_CONTROL_PAGED_RESULTS_OID, ac->new_req->controls[0]->oid) != 0) {
 124                 /* something wrong here */
 125                 return LDB_ERR_OPERATIONS_ERROR;
 126         }
 127
 128         req_control = talloc_get_type(ac->new_req->controls[0]->data, struct ldb_paged_control);
 129
 130         if (req_control->cookie) {
 131                 talloc_free(req_control->cookie);
 132         }
 133
 134         req_control->cookie = talloc_memdup(req_control,
 135                                             rep_control->cookie,
 136                                             rep_control->cookie_len);
 137         req_control->cookie_len = rep_control->cookie_len;
 138
 139         ac->pending = True;
 140         return LDB_SUCCESS;
 141 }
 142
 143 static int store_referral(char *referral, struct ps_context *ac)
 144 {
 145         ac->saved_referrals = talloc_realloc(ac, ac->saved_referrals, char *, ac->num_referrals + 2);
 146         if (!ac->saved_referrals) {
 147                 return LDB_ERR_OPERATIONS_ERROR;
 148         }
 149
 150         ac->saved_referrals[ac->num_referrals] = talloc_strdup(ac->saved_referrals, referral);
 151         if (!ac->saved_referrals[ac->num_referrals]) {
 152                 return LDB_ERR_OPERATIONS_ERROR;
 153         }
 154
 155         ac->num_referrals++;
 156         ac->saved_referrals[ac->num_referrals] = NULL;
 157
 158         return LDB_SUCCESS;
 159 }
 160
 161 static int send_referrals(struct ldb_context *ldb, struct ps_context *ac)
 162 {
 163         struct ldb_reply *ares;
 164         int i;
 165
 166         for (i = 0; i < ac->num_referrals; i++) {
 167                 ares = talloc_zero(ac, struct ldb_reply);
 168                 if (!ares) {
 169                         return LDB_ERR_OPERATIONS_ERROR;
 170                 }
 171
 172                 ares->type = LDB_REPLY_REFERRAL;
 173                 ares->referral = ac->saved_referrals[i];
 174
 175                 ac->up_callback(ldb, ac->up_context, ares);
 176         }
 177
 178         return LDB_SUCCESS;
 179 }
 180
 181 static int ps_callback(struct ldb_context *ldb, void *context, struct ldb_reply *ares)
 182 {
 183         struct ps_context *ac = NULL;
 184         int ret = LDB_ERR_OPERATIONS_ERROR;
 185
 186         if (!context || !ares) {
 187                 ldb_set_errstring(ldb, "NULL Context or Result in callback");
 188                 goto error;
 189         }
 190
 191         ac = talloc_get_type(context, struct ps_context);
 192
 193         switch (ares->type) {
 194         case LDB_REPLY_ENTRY:
 195                 ac->up_callback(ldb, ac->up_context, ares);
 196                 break;
 197
 198         case LDB_REPLY_REFERRAL:
 199                 ret = store_referral(ares->referral, ac);
 200                 if (ret != LDB_SUCCESS) {
 201                         goto error;
 202                 }
 203                 break;
 204
 205         case LDB_REPLY_DONE:
 206                 ret = check_ps_continuation(ares, ac);
 207                 if (ret != LDB_SUCCESS) {
 208                         goto error;
 209                 }
 210                 if (!ac->pending) {
 211                         /* send referrals */
 212                         ret = send_referrals(ldb, ac);
 213                         if (ret != LDB_SUCCESS) {
 214                                 goto error;
 215                         }
 216
 217                         /* send REPLY_DONE */
 218                         ac->up_callback(ldb, ac->up_context, ares);
 219                 }
 220                 break;
 221         default:
 222                 goto error;
 223         }
 224
 225         return LDB_SUCCESS;
 226
 227 error:
 228         talloc_free(ares);
 229         return ret;
 230 }
 231
 232 static int ps_search(struct ldb_module *module, struct ldb_request *req)
 233 {
 234         struct private_data *private_data;
 235         struct ldb_paged_control *control;
 236         struct ps_context *ac;
 237         struct ldb_handle *h;
 238
 239         private_data = talloc_get_type(module->private_data, struct private_data);
 240
 241         /* check if paging is supported and if there is a any control */
 242         if (!private_data || !private_data->paged_supported || req->controls) {
 243                 /* do not touch this request paged controls not
 244                  * supported or explicit controls have been set or we
 245                  * are just not setup yet */
 246                 return ldb_next_request(module, req);
 247         }
 248
 249         if (!req->callback || !req->context) {
 250                 ldb_set_errstring(module->ldb,
 251                                   "Async interface called with NULL callback function or NULL context");
 252                 return LDB_ERR_OPERATIONS_ERROR;
 253         }
 254
 255         h = init_handle(req, module, req->context, req->callback);
 256         if (!h) {
 257                 return LDB_ERR_OPERATIONS_ERROR;
 258         }
 259         ac = talloc_get_type(h->private_data, struct ps_context);
 260
 261         ac->new_req = talloc(ac, struct ldb_request);
 262         if (!ac->new_req) return LDB_ERR_OPERATIONS_ERROR;
 263
 264         ac->new_req->controls = talloc_array(ac->new_req, struct ldb_control *, 2);
 265         if (!ac->new_req->controls) return LDB_ERR_OPERATIONS_ERROR;
 266
 267         ac->new_req->controls[0] = talloc(ac->new_req->controls, struct ldb_control);
 268         if (!ac->new_req->controls[0]) return LDB_ERR_OPERATIONS_ERROR;
 269
 270         control = talloc(ac->new_req->controls[0], struct ldb_paged_control);
 271         if (!control) return LDB_ERR_OPERATIONS_ERROR;
 272
 273         control->size = PS_DEFAULT_PAGE_SIZE;
 274         control->cookie = NULL;
 275         control->cookie_len = 0;
 276
 277         ac->new_req->controls[0]->oid = LDB_CONTROL_PAGED_RESULTS_OID;
 278         ac->new_req->controls[0]->critical = 1;
 279         ac->new_req->controls[0]->data = control;
 280
 281         ac->new_req->controls[1] = NULL;
 282
 283         ac->new_req->operation = req->operation;
 284         ac->new_req->op.search.base = req->op.search.base;
 285         ac->new_req->op.search.scope = req->op.search.scope;
 286         ac->new_req->op.search.tree = req->op.search.tree;
 287         ac->new_req->op.search.attrs = req->op.search.attrs;
 288         ac->new_req->context = ac;
 289         ac->new_req->callback = ps_callback;
 290         ldb_set_timeout_from_prev_req(module->ldb, req, ac->new_req);
 291
 292         req->handle = h;
 293
 294         return ldb_next_request(module, ac->new_req);
 295 }
 296
 297 static int ps_continuation(struct ldb_handle *handle)
 298 {
 299         struct ps_context *ac;
 300
 301         if (!handle || !handle->private_data) {
 302                 return LDB_ERR_OPERATIONS_ERROR;
 303         }
 304
 305         ac = talloc_get_type(handle->private_data, struct ps_context);
 306
 307         /* reset the requests handle */
 308         ac->new_req->handle = NULL;
 309
 310         return ldb_next_request(handle->module, ac->new_req);
 311 }
 312
 313 static int ps_wait_none(struct ldb_handle *handle)
 314 {
 315         struct ps_context *ac;
 316         int ret;
 317
 318         if (!handle || !handle->private_data) {
 319                 return LDB_ERR_OPERATIONS_ERROR;
 320         }
 321
 322         if (handle->state == LDB_ASYNC_DONE) {
 323                 return handle->status;
 324         }
 325
 326         handle->state = LDB_ASYNC_PENDING;
 327         handle->status = LDB_SUCCESS;
 328
 329         ac = talloc_get_type(handle->private_data, struct ps_context);
 330
 331         ret = ldb_wait(ac->new_req->handle, LDB_WAIT_NONE);
 332
 333         if (ret != LDB_SUCCESS) {
 334                 handle->status = ret;
 335                 goto done;
 336         }
 337
 338         if (ac->new_req->handle->status != LDB_SUCCESS) {
 339                 handle->status = ac->new_req->handle->status;
 340                 goto done;
 341         }
 342
 343         if (ac->new_req->handle->state != LDB_ASYNC_DONE) {
 344                 return LDB_SUCCESS;
 345         }
 346
 347         /* see if we need to send another request for the next batch */
 348         if (ac->pending) {
 349                 ret = ps_continuation(handle);
 350                 if (ret != LDB_SUCCESS) {
 351                         handle->status = ret;
 352                         goto done;
 353                 }
 354
 355                 /* continue the search with the next request */
 356                 return LDB_SUCCESS;
 357         }
 358
 359         ret = LDB_SUCCESS;
 360
 361 done:
 362         handle->state = LDB_ASYNC_DONE;
 363         return ret;
 364 }
 365
 366 static int ps_wait_all(struct ldb_handle *handle)
 367 {
 368         int ret;
 369
 370         while (handle->state != LDB_ASYNC_DONE) {
 371                 ret = ps_wait_none(handle);
 372                 if (ret != LDB_SUCCESS) {
 373                         return ret;
 374                 }
 375         }
 376
 377         return handle->status;
 378 }
 379
 380 static int ps_wait(struct ldb_handle *handle, enum ldb_wait_type type)
 381 {
 382         if (type == LDB_WAIT_ALL) {
 383                 return ps_wait_all(handle);
 384         } else {
 385                 return ps_wait_none(handle);
 386         }
 387 }
 388
 389 static int check_supported_paged(struct ldb_context *ldb, void *context,
 390                                  struct ldb_reply *ares)
 391 {
 392         struct private_data *data;
 393         data = talloc_get_type(context,
 394                                struct private_data);
 395         if (ares->type == LDB_REPLY_ENTRY) {
 396                 if (ldb_msg_check_string_attribute(ares->message,
 397                                                    "supportedControl",
 398                                                    LDB_CONTROL_PAGED_RESULTS_OID)) {
 399                         data->paged_supported = True;
 400                 }
 401         }
 402         return LDB_SUCCESS;
 403 }
 404
 405
 406 static int ps_init(struct ldb_module *module)
 407 {
 408         static const char *attrs[] = { "supportedControl", NULL };
 409         struct private_data *data;
 410         int ret;
 411         struct ldb_request *req;
 412
 413         data = talloc(module, struct private_data);
 414         if (data == NULL) {
 415                 return LDB_ERR_OTHER;
 416         }
 417         module->private_data = data;
 418         data->paged_supported = False;
 419
 420         req = talloc(module, struct ldb_request);
 421         if (req == NULL) {
 422                 ldb_set_errstring(module->ldb, "Out of Memory");
 423                 return LDB_ERR_OPERATIONS_ERROR;
 424         }
 425
 426         req->operation = LDB_SEARCH;
 427         req->op.search.base = ldb_dn_new(req);
 428         req->op.search.scope = LDB_SCOPE_BASE;
 429
 430         req->op.search.tree = ldb_parse_tree(req, "objectClass=*");
 431         if (req->op.search.tree == NULL) {
 432                 ldb_set_errstring(module->ldb, "Unable to parse search expression");
 433                 talloc_free(req);
 434                 return LDB_ERR_OPERATIONS_ERROR;
 435         }
 436
 437         req->op.search.attrs = attrs;
 438         req->controls = NULL;
 439         req->context = data;
 440         req->callback = check_supported_paged;
 441         ldb_set_timeout(module->ldb, req, 0); /* use default timeout */
 442
 443         ret = ldb_next_request(module, req);
 444
 445         if (ret == LDB_SUCCESS) {
 446                 ret = ldb_wait(req->handle, LDB_WAIT_ALL);
 447         }
 448
 449         talloc_free(req);
 450         if (ret != LDB_SUCCESS) {
 451                 return ret;
 452         }
 453
 454         return ldb_next_init(module);
 455 }
 456
 457 static const struct ldb_module_ops ps_ops = {
 458         .name           = "paged_searches",
 459         .search         = ps_search,
 460         .wait           = ps_wait,
 461         .init_context   = ps_init
 462 };
 463
 464 int ldb_paged_searches_init(void)
 465 {
 466         return ldb_register_module(&ps_ops);
 467 }
 468