source4/dsdb/samdb/ldb_modules/ranged_results.c

   1 /*
   2    ldb database library
   3
   4    Copyright (C) Andrew Bartlett 2007
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 /*
  21  *  Name: ldb
  22  *
  23  *  Component: ldb ranged results module
  24  *
  25  *  Description: munge AD-style 'ranged results' requests into
  26  *  requests for all values in an attribute, then return the range to
  27  *  the client.
  28  *
  29  *  Author: Andrew Bartlett
  30  */
  31
  32 #include "includes.h"
  33 #include "ldb_module.h"
  34
  35 struct rr_context {
  36         struct ldb_module *module;
  37         struct ldb_request *req;
  38 };
  39
  40 static struct rr_context *rr_init_context(struct ldb_module *module,
  41                                           struct ldb_request *req)
  42 {
  43         struct rr_context *ac;
  44
  45         ac = talloc_zero(req, struct rr_context);
  46         if (ac == NULL) {
  47                 ldb_set_errstring(ldb_module_get_ctx(module), "Out of Memory");
  48                 return NULL;
  49         }
  50
  51         ac->module = module;
  52         ac->req = req;
  53
  54         return ac;
  55 }
  56
  57 static int rr_search_callback(struct ldb_request *req, struct ldb_reply *ares)
  58 {
  59         struct ldb_context *ldb;
  60         struct rr_context *ac;
  61         unsigned int i, j;
  62         TALLOC_CTX *temp_ctx;
  63
  64         ac = talloc_get_type(req->context, struct rr_context);
  65         ldb = ldb_module_get_ctx(ac->module);
  66
  67         if (!ares) {
  68                 return ldb_module_done(ac->req, NULL, NULL,
  69                                         LDB_ERR_OPERATIONS_ERROR);
  70         }
  71         if (ares->error != LDB_SUCCESS) {
  72                 return ldb_module_done(ac->req, ares->controls,
  73                                         ares->response, ares->error);
  74         }
  75
  76         if (ares->type == LDB_REPLY_REFERRAL) {
  77                 return ldb_module_send_referral(ac->req, ares->referral);
  78         }
  79
  80         if (ares->type == LDB_REPLY_DONE) {
  81                 return ldb_module_done(ac->req, ares->controls,
  82                                         ares->response, ares->error);
  83         }
  84
  85         /* LDB_REPLY_ENTRY */
  86
  87         temp_ctx = talloc_new(ac->req);
  88         if (!temp_ctx) {
  89                 ldb_module_oom(ac->module);
  90                 return ldb_module_done(ac->req, NULL, NULL,
  91                                        LDB_ERR_OPERATIONS_ERROR);
  92         }
  93
  94         /* Find those that are range requests from the attribute list */
  95         for (i = 0; ac->req->op.search.attrs[i]; i++) {
  96                 char *p, *new_attr;
  97                 const char *end_str;
  98                 unsigned int start, end, orig_num_values;
  99                 struct ldb_message_element *el;
 100                 struct ldb_val *orig_values;
 101
 102                 p = strchr(ac->req->op.search.attrs[i], ';');
 103                 if (!p) {
 104                         continue;
 105                 }
 106                 if (strncasecmp(p, ";range=", strlen(";range=")) != 0) {
 107                         continue;
 108                 }
 109                 if (sscanf(p, ";range=%u-%u", &start, &end) != 2) {
 110                         if (sscanf(p, ";range=%u-*", &start) == 1) {
 111                                 end = (unsigned int)-1;
 112                         } else {
 113                                 continue;
 114                         }
 115                 }
 116                 new_attr = talloc_strndup(temp_ctx,
 117                                           ac->req->op.search.attrs[i],
 118                                           (size_t)(p - ac->req->op.search.attrs[i]));
 119
 120                 if (!new_attr) {
 121                         ldb_oom(ldb);
 122                         return ldb_module_done(ac->req, NULL, NULL,
 123                                                 LDB_ERR_OPERATIONS_ERROR);
 124                 }
 125                 el = ldb_msg_find_element(ares->message, new_attr);
 126                 talloc_free(new_attr);
 127                 if (!el) {
 128                         continue;
 129                 }
 130                 if (end >= (el->num_values - 1)) {
 131                         /* Need to leave the requested attribute in
 132                          * there (so add an empty one to match) */
 133                         end_str = "*";
 134                         end = el->num_values - 1;
 135                 } else {
 136                         end_str = talloc_asprintf(temp_ctx, "%u", end);
 137                         if (!end_str) {
 138                                 ldb_oom(ldb);
 139                                 return ldb_module_done(ac->req, NULL, NULL,
 140                                                         LDB_ERR_OPERATIONS_ERROR);
 141                         }
 142                 }
 143                 /* If start is greater then where we are find the end to be */
 144                 if (start > end) {
 145                         el->num_values = 0;
 146                         el->values = NULL;
 147                 } else {
 148                         orig_values = el->values;
 149                         orig_num_values = el->num_values;
 150
 151                         if ((start + end < start) || (start + end < end)) {
 152                                 ldb_asprintf_errstring(ldb,
 153                                         "range request error: start or end would overflow!");
 154                                 return ldb_module_done(ac->req, NULL, NULL,
 155                                                         LDB_ERR_UNWILLING_TO_PERFORM);
 156                         }
 157
 158                         el->num_values = 0;
 159
 160                         el->values = talloc_array(ares->message->elements,
 161                                                   struct ldb_val,
 162                                                   (end - start) + 1);
 163                         if (!el->values) {
 164                                 ldb_oom(ldb);
 165                                 return ldb_module_done(ac->req, NULL, NULL,
 166                                                         LDB_ERR_OPERATIONS_ERROR);
 167                         }
 168                         for (j=start; j <= end; j++) {
 169                                 el->values[el->num_values] = orig_values[j];
 170                                 el->num_values++;
 171                         }
 172                 }
 173                 el->name = talloc_asprintf(ares->message->elements,
 174                                            "%s;range=%u-%s", el->name, start,
 175                                            end_str);
 176                 if (!el->name) {
 177                         ldb_oom(ldb);
 178                         return ldb_module_done(ac->req, NULL, NULL,
 179                                                 LDB_ERR_OPERATIONS_ERROR);
 180                 }
 181         }
 182
 183         talloc_free(temp_ctx);
 184
 185         return ldb_module_send_entry(ac->req, ares->message, ares->controls);
 186 }
 187
 188 /* search */
 189 static int rr_search(struct ldb_module *module, struct ldb_request *req)
 190 {
 191         struct ldb_context *ldb;
 192         unsigned int i;
 193         unsigned int start, end;
 194         const char **new_attrs = NULL;
 195         bool found_rr = false;
 196         struct ldb_request *down_req;
 197         struct rr_context *ac;
 198         int ret;
 199
 200         ldb = ldb_module_get_ctx(module);
 201
 202         /* Strip the range request from the attribute */
 203         for (i = 0; req->op.search.attrs && req->op.search.attrs[i]; i++) {
 204                 char *p;
 205                 new_attrs = talloc_realloc(req, new_attrs, const char *, i+2);
 206                 new_attrs[i] = req->op.search.attrs[i];
 207                 new_attrs[i+1] = NULL;
 208                 p = strchr(new_attrs[i], ';');
 209                 if (!p) {
 210                         continue;
 211                 }
 212                 if (strncasecmp(p, ";range=", strlen(";range=")) != 0) {
 213                         continue;
 214                 }
 215                 end = (unsigned int)-1;
 216                 if (sscanf(p, ";range=%u-*", &start) != 1) {
 217                         if (sscanf(p, ";range=%u-%u", &start, &end) != 2) {
 218                                 ldb_asprintf_errstring(ldb,
 219                                         "range request error: "
 220                                         "range request malformed");
 221                                 return LDB_ERR_UNWILLING_TO_PERFORM;
 222                         }
 223                 }
 224                 if (start > end) {
 225                         ldb_asprintf_errstring(ldb, "range request error: start must not be greater than end");
 226                         return LDB_ERR_UNWILLING_TO_PERFORM;
 227                 }
 228
 229                 found_rr = true;
 230                 new_attrs[i] = talloc_strndup(new_attrs, new_attrs[i],
 231                                               (size_t)(p - new_attrs[i]));
 232
 233                 if (!new_attrs[i]) {
 234                         return ldb_oom(ldb);
 235                 }
 236         }
 237
 238         if (found_rr) {
 239                 ac = rr_init_context(module, req);
 240                 if (!ac) {
 241                         return ldb_operr(ldb);
 242                 }
 243
 244                 ret = ldb_build_search_req_ex(&down_req, ldb, ac,
 245                                               req->op.search.base,
 246                                               req->op.search.scope,
 247                                               req->op.search.tree,
 248                                               new_attrs,
 249                                               req->controls,
 250                                               ac, rr_search_callback,
 251                                               req);
 252                 LDB_REQ_SET_LOCATION(down_req);
 253                 if (ret != LDB_SUCCESS) {
 254                         return ret;
 255                 }
 256                 return ldb_next_request(module, down_req);
 257         }
 258
 259         /* No change, just run the original request as if we were never here */
 260         talloc_free(new_attrs);
 261         return ldb_next_request(module, req);
 262 }
 263
 264 static const struct ldb_module_ops ldb_ranged_results_module_ops = {
 265         .name              = "ranged_results",
 266         .search            = rr_search,
 267 };
 268
 269 int ldb_ranged_results_module_init(const char *version)
 270 {
 271         LDB_MODULE_CHECK_VERSION(version);
 272         return ldb_register_module(&ldb_ranged_results_module_ops);
 273 }