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 "ldb_module.h"
  33
  34 struct rr_context {
  35         struct ldb_module *module;
  36         struct ldb_request *req;
  37 };
  38
  39 static struct rr_context *rr_init_context(struct ldb_module *module,
  40                                           struct ldb_request *req)
  41 {
  42         struct rr_context *ac;
  43
  44         ac = talloc_zero(req, struct rr_context);
  45         if (ac == NULL) {
  46                 ldb_set_errstring(ldb_module_get_ctx(module), "Out of Memory");
  47                 return NULL;
  48         }
  49
  50         ac->module = module;
  51         ac->req = req;
  52
  53         return ac;
  54 }
  55
  56 static int rr_search_callback(struct ldb_request *req, struct ldb_reply *ares)
  57 {
  58         struct ldb_context *ldb;
  59         struct rr_context *ac;
  60         int i, j;
  61
  62         ac = talloc_get_type(req->context, struct rr_context);
  63         ldb = ldb_module_get_ctx(ac->module);
  64
  65         if (!ares) {
  66                 return ldb_module_done(ac->req, NULL, NULL,
  67                                         LDB_ERR_OPERATIONS_ERROR);
  68         }
  69         if (ares->error != LDB_SUCCESS) {
  70                 return ldb_module_done(ac->req, ares->controls,
  71                                         ares->response, ares->error);
  72         }
  73
  74         if (ares->type == LDB_REPLY_REFERRAL) {
  75                 return ldb_module_send_referral(ac->req, ares->referral);
  76         }
  77
  78         if (ares->type == LDB_REPLY_DONE) {
  79                 return ldb_module_done(ac->req, ares->controls,
  80                                         ares->response, ares->error);
  81         }
  82
  83         /* LDB_REPLY_ENTRY */
  84
  85         /* Find those that are range requests from the attribute list */
  86         for (i = 0; ac->req->op.search.attrs[i]; i++) {
  87                 char *p, *new_attr;
  88                 const char *end_str;
  89                 unsigned int start, end, orig_num_values;
  90                 struct ldb_message_element *el;
  91                 struct ldb_val *orig_values;
  92                 p = strchr(ac->req->op.search.attrs[i], ';');
  93                 if (!p) {
  94                         continue;
  95                 }
  96                 if (strncasecmp(p, ";range=", strlen(";range=")) != 0) {
  97                         continue;
  98                 }
  99                 if (sscanf(p, ";range=%u-%u", &start, &end) != 2) {
 100                         if (sscanf(p, ";range=%u-*", &start) == 1) {
 101                                 end = (unsigned int)-1;
 102                         } else {
 103                                 continue;
 104                         }
 105                 }
 106                 new_attr = talloc_strndup(ac->req,
 107                                           ac->req->op.search.attrs[i],
 108                                           (size_t)(p - ac->req->op.search.attrs[i]));
 109
 110                 if (!new_attr) {
 111                         ldb_oom(ldb);
 112                         return ldb_module_done(ac->req, NULL, NULL,
 113                                                 LDB_ERR_OPERATIONS_ERROR);
 114                 }
 115                 el = ldb_msg_find_element(ares->message, new_attr);
 116                 talloc_free(new_attr);
 117                 if (!el) {
 118                         continue;
 119                 }
 120                 if (end >= (el->num_values - 1)) {
 121                         /* Need to leave the requested attribute in
 122                          * there (so add an empty one to match) */
 123                         end_str = "*";
 124                         end = el->num_values - 1;
 125                 } else {
 126                         end_str = talloc_asprintf(el, "%u", end);
 127                         if (!end_str) {
 128                                 ldb_oom(ldb);
 129                                 return ldb_module_done(ac->req, NULL, NULL,
 130                                                         LDB_ERR_OPERATIONS_ERROR);
 131                         }
 132                 }
 133                 /* If start is greater then where we are find the end to be */
 134                 if (start > end) {
 135                         el->num_values = 0;
 136                         el->values = NULL;
 137                 } else {
 138                         orig_values = el->values;
 139                         orig_num_values = el->num_values;
 140
 141                         if ((start + end < start) || (start + end < end)) {
 142                                 ldb_asprintf_errstring(ldb,
 143                                         "range request error: start or end would overflow!");
 144                                 return ldb_module_done(ac->req, NULL, NULL,
 145                                                         LDB_ERR_UNWILLING_TO_PERFORM);
 146                         }
 147
 148                         el->num_values = 0;
 149
 150                         el->values = talloc_array(el, struct ldb_val, (end - start) + 1);
 151                         if (!el->values) {
 152                                 ldb_oom(ldb);
 153                                 return ldb_module_done(ac->req, NULL, NULL,
 154                                                         LDB_ERR_OPERATIONS_ERROR);
 155                         }
 156                         for (j=start; j <= end; j++) {
 157                                 el->values[el->num_values] = orig_values[j];
 158                                 el->num_values++;
 159                         }
 160                 }
 161                 el->name = talloc_asprintf(el, "%s;range=%u-%s", el->name, start, end_str);
 162                 if (!el->name) {
 163                         ldb_oom(ldb);
 164                         return ldb_module_done(ac->req, NULL, NULL,
 165                                                 LDB_ERR_OPERATIONS_ERROR);
 166                 }
 167         }
 168
 169         return ldb_module_send_entry(ac->req, ares->message, ares->controls);
 170 }
 171
 172 /* search */
 173 static int rr_search(struct ldb_module *module, struct ldb_request *req)
 174 {
 175         struct ldb_context *ldb;
 176         int i;
 177         unsigned int start, end;
 178         const char **new_attrs = NULL;
 179         bool found_rr = false;
 180         struct ldb_request *down_req;
 181         struct rr_context *ac;
 182         int ret;
 183
 184         ldb = ldb_module_get_ctx(module);
 185
 186         /* Strip the range request from the attribute */
 187         for (i = 0; req->op.search.attrs && req->op.search.attrs[i]; i++) {
 188                 char *p;
 189                 new_attrs = talloc_realloc(req, new_attrs, const char *, i+2);
 190                 new_attrs[i] = req->op.search.attrs[i];
 191                 new_attrs[i+1] = NULL;
 192                 p = strchr(new_attrs[i], ';');
 193                 if (!p) {
 194                         continue;
 195                 }
 196                 if (strncasecmp(p, ";range=", strlen(";range=")) != 0) {
 197                         continue;
 198                 }
 199                 end = (unsigned int)-1;
 200                 if (sscanf(p, ";range=%u-*", &start) != 1) {
 201                         if (sscanf(p, ";range=%u-%u", &start, &end) != 2) {
 202                                 ldb_asprintf_errstring(ldb,
 203                                         "range request error: "
 204                                         "range request malformed");
 205                                 return LDB_ERR_UNWILLING_TO_PERFORM;
 206                         }
 207                 }
 208                 if (start > end) {
 209                         ldb_asprintf_errstring(ldb, "range request error: start must not be greater than end");
 210                         return LDB_ERR_UNWILLING_TO_PERFORM;
 211                 }
 212
 213                 found_rr = true;
 214                 new_attrs[i] = talloc_strndup(new_attrs, new_attrs[i],
 215                                               (size_t)(p - new_attrs[i]));
 216
 217                 if (!new_attrs[i]) {
 218                         ldb_oom(ldb);
 219                         return LDB_ERR_OPERATIONS_ERROR;
 220                 }
 221         }
 222
 223         if (found_rr) {
 224                 ac = rr_init_context(module, req);
 225                 if (!ac) {
 226                         return LDB_ERR_OPERATIONS_ERROR;
 227                 }
 228
 229                 ret = ldb_build_search_req_ex(&down_req, ldb, ac,
 230                                               req->op.search.base,
 231                                               req->op.search.scope,
 232                                               req->op.search.tree,
 233                                               new_attrs,
 234                                               req->controls,
 235                                               ac, rr_search_callback,
 236                                               req);
 237                 if (ret != LDB_SUCCESS) {
 238                         return ret;
 239                 }
 240                 return ldb_next_request(module, down_req);
 241         }
 242
 243         /* No change, just run the original request as if we were never here */
 244         talloc_free(new_attrs);
 245         return ldb_next_request(module, req);
 246 }
 247
 248 const struct ldb_module_ops ldb_ranged_results_module_ops = {
 249         .name              = "ranged_results",
 250         .search            = rr_search,
 251 };