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;
  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
 150                         if ((start + end < start) || (start + end < end)) {
 151                                 ldb_asprintf_errstring(ldb,
 152                                         "range request error: start or end would overflow!");
 153                                 return ldb_module_done(ac->req, NULL, NULL,
 154                                                         LDB_ERR_UNWILLING_TO_PERFORM);
 155                         }
 156
 157                         el->num_values = 0;
 158
 159                         el->values = talloc_array(ares->message->elements,
 160                                                   struct ldb_val,
 161                                                   (end - start) + 1);
 162                         if (!el->values) {
 163                                 ldb_oom(ldb);
 164                                 return ldb_module_done(ac->req, NULL, NULL,
 165                                                         LDB_ERR_OPERATIONS_ERROR);
 166                         }
 167                         for (j=start; j <= end; j++) {
 168                                 el->values[el->num_values] = orig_values[j];
 169                                 el->num_values++;
 170                         }
 171                 }
 172                 el->name = talloc_asprintf(ares->message->elements,
 173                                            "%s;range=%u-%s", el->name, start,
 174                                            end_str);
 175                 if (!el->name) {
 176                         ldb_oom(ldb);
 177                         return ldb_module_done(ac->req, NULL, NULL,
 178                                                 LDB_ERR_OPERATIONS_ERROR);
 179                 }
 180         }
 181
 182         talloc_free(temp_ctx);
 183
 184         return ldb_module_send_entry(ac->req, ares->message, ares->controls);
 185 }
 186
 187 /* search */
 188 static int rr_search(struct ldb_module *module, struct ldb_request *req)
 189 {
 190         struct ldb_context *ldb;
 191         unsigned int i;
 192         unsigned int start, end;
 193         const char **new_attrs = NULL;
 194         bool found_rr = false;
 195         struct ldb_request *down_req;
 196         struct rr_context *ac;
 197         int ret;
 198
 199         ldb = ldb_module_get_ctx(module);
 200
 201         /* Strip the range request from the attribute */
 202         for (i = 0; req->op.search.attrs && req->op.search.attrs[i]; i++) {
 203                 char *p;
 204                 new_attrs = talloc_realloc(req, new_attrs, const char *, i+2);
 205                 new_attrs[i] = req->op.search.attrs[i];
 206                 new_attrs[i+1] = NULL;
 207                 p = strchr(new_attrs[i], ';');
 208                 if (!p) {
 209                         continue;
 210                 }
 211                 if (strncasecmp(p, ";range=", strlen(";range=")) != 0) {
 212                         continue;
 213                 }
 214                 end = (unsigned int)-1;
 215                 if (sscanf(p, ";range=%u-*", &start) != 1) {
 216                         if (sscanf(p, ";range=%u-%u", &start, &end) != 2) {
 217                                 ldb_asprintf_errstring(ldb,
 218                                         "range request error: "
 219                                         "range request malformed");
 220                                 return LDB_ERR_UNWILLING_TO_PERFORM;
 221                         }
 222                 }
 223                 if (start > end) {
 224                         ldb_asprintf_errstring(ldb, "range request error: start must not be greater than end");
 225                         return LDB_ERR_UNWILLING_TO_PERFORM;
 226                 }
 227
 228                 found_rr = true;
 229                 new_attrs[i] = talloc_strndup(new_attrs, new_attrs[i],
 230                                               (size_t)(p - new_attrs[i]));
 231
 232                 if (!new_attrs[i]) {
 233                         return ldb_oom(ldb);
 234                 }
 235         }
 236
 237         if (found_rr) {
 238                 ac = rr_init_context(module, req);
 239                 if (!ac) {
 240                         return ldb_operr(ldb);
 241                 }
 242
 243                 ret = ldb_build_search_req_ex(&down_req, ldb, ac,
 244                                               req->op.search.base,
 245                                               req->op.search.scope,
 246                                               req->op.search.tree,
 247                                               new_attrs,
 248                                               req->controls,
 249                                               ac, rr_search_callback,
 250                                               req);
 251                 LDB_REQ_SET_LOCATION(down_req);
 252                 if (ret != LDB_SUCCESS) {
 253                         return ret;
 254                 }
 255                 return ldb_next_request(module, down_req);
 256         }
 257
 258         /* No change, just run the original request as if we were never here */
 259         talloc_free(new_attrs);
 260         return ldb_next_request(module, req);
 261 }
 262
 263 static const struct ldb_module_ops ldb_ranged_results_module_ops = {
 264         .name              = "ranged_results",
 265         .search            = rr_search,
 266 };
 267
 268 int ldb_ranged_results_module_init(const char *version)
 269 {
 270         LDB_MODULE_CHECK_VERSION(version);
 271         return ldb_register_module(&ldb_ranged_results_module_ops);
 272 }