source/lib/ldb/common/ldb_modules.c

   1
   2 /*
   3    ldb database library
   4
   5    Copyright (C) Simo Sorce  2004
   6
   7      ** NOTE! The following LGPL license applies to the ldb
   8      ** library. This does NOT imply that all of Samba is released
   9      ** under the LGPL
  10
  11    This library is free software; you can redistribute it and/or
  12    modify it under the terms of the GNU Lesser General Public
  13    License as published by the Free Software Foundation; either
  14    version 2 of the License, or (at your option) any later version.
  15
  16    This library is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19    Lesser General Public License for more details.
  20
  21    You should have received a copy of the GNU Lesser General Public
  22    License along with this library; if not, write to the Free Software
  23    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  24 */
  25
  26 /*
  27  *  Name: ldb
  28  *
  29  *  Component: ldb modules core
  30  *
  31  *  Description: core modules routines
  32  *
  33  *  Author: Simo Sorce
  34  */
  35
  36 #include "includes.h"
  37 #include "ldb/include/includes.h"
  38
  39 #ifdef _SAMBA_BUILD_
  40 #include "build.h"
  41 #include "dynconfig.h"
  42 #endif
  43
  44 #define LDB_MODULE_PREFIX       "modules:"
  45 #define LDB_MODULE_PREFIX_LEN   8
  46
  47 static char *talloc_strdup_no_spaces(struct ldb_context *ldb, const char *string)
  48 {
  49         int i, len;
  50         char *trimmed;
  51
  52         trimmed = talloc_strdup(ldb, string);
  53         if (!trimmed) {
  54                 ldb_debug(ldb, LDB_DEBUG_FATAL, "Out of Memory in talloc_strdup_trim_spaces()\n");
  55                 return NULL;
  56         }
  57
  58         len = strlen(trimmed);
  59         for (i = 0; trimmed[i] != '\0'; i++) {
  60                 switch (trimmed[i]) {
  61                 case ' ':
  62                 case '\t':
  63                 case '\n':
  64                         memmove(&trimmed[i], &trimmed[i + 1], len -i -1);
  65                         break;
  66                 }
  67         }
  68
  69         return trimmed;
  70 }
  71
  72
  73 /* modules are called in inverse order on the stack.
  74    Lets place them as an admin would think the right order is.
  75    Modules order is important */
  76 static const char **ldb_modules_list_from_string(struct ldb_context *ldb, TALLOC_CTX *mem_ctx, const char *string)
  77 {
  78         char **modules = NULL;
  79         const char **m;
  80         char *modstr, *p;
  81         int i;
  82
  83         /* spaces not admitted */
  84         modstr = talloc_strdup_no_spaces(mem_ctx, string);
  85         if ( ! modstr) {
  86                 return NULL;
  87         }
  88
  89         modules = talloc_realloc(mem_ctx, modules, char *, 2);
  90         if ( ! modules ) {
  91                 ldb_debug(ldb, LDB_DEBUG_FATAL, "Out of Memory in ldb_modules_list_from_string()\n");
  92                 talloc_free(modstr);
  93                 return NULL;
  94         }
  95         talloc_steal(modules, modstr);
  96
  97         i = 0;
  98         while ((p = strrchr(modstr, ',')) != NULL) {
  99                 *p = '\0';
 100                 p++;
 101                 modules[i] = p;
 102
 103                 i++;
 104                 modules = talloc_realloc(mem_ctx, modules, char *, i + 2);
 105                 if ( ! modules ) {
 106                         ldb_debug(ldb, LDB_DEBUG_FATAL, "Out of Memory in ldb_modules_list_from_string()\n");
 107                         return NULL;
 108                 }
 109
 110         }
 111         modules[i] = modstr;
 112
 113         modules[i + 1] = NULL;
 114
 115         m = (const char **)modules;
 116
 117         return m;
 118 }
 119
 120 static struct ops_list_entry {
 121         const struct ldb_module_ops *ops;
 122         struct ops_list_entry *next;
 123 } *registered_modules = NULL;
 124
 125 static const struct ldb_module_ops *ldb_find_module_ops(const char *name)
 126 {
 127         struct ops_list_entry *e;
 128
 129         for (e = registered_modules; e; e = e->next) {
 130                 if (strcmp(e->ops->name, name) == 0)
 131                         return e->ops;
 132         }
 133
 134         return NULL;
 135 }
 136
 137 #ifdef HAVE_LDAP
 138 #define LDAP_INIT ldb_ldap_init,
 139 #else
 140 #define LDAP_INIT
 141 #endif
 142
 143 #ifdef HAVE_SQLITE3
 144 #define SQLITE3_INIT ldb_sqlite3_init,
 145 #else
 146 #define SQLITE3_INIT
 147 #endif
 148
 149 #ifndef STATIC_ldb_MODULES
 150 #define STATIC_ldb_MODULES \
 151         {       \
 152                 LDAP_INIT \
 153                 SQLITE3_INIT \
 154                 ldb_tdb_init,   \
 155                 ldb_schema_init,        \
 156                 ldb_operational_init,   \
 157                 ldb_rdn_name_init,      \
 158                 ldb_objectclass_init,   \
 159                 ldb_paged_results_init, \
 160                 ldb_sort_init,          \
 161                 NULL                    \
 162         }
 163 #endif
 164
 165 int ldb_global_init(void)
 166 {
 167         static int (*static_init_fns[])(void) = STATIC_ldb_MODULES;
 168
 169         static int initialized = 0;
 170         int ret = 0, i;
 171
 172         if (initialized)
 173                 return 0;
 174
 175         initialized = 1;
 176
 177         for (i = 0; static_init_fns[i]; i++) {
 178                 if (static_init_fns[i]() == -1)
 179                         ret = -1;
 180         }
 181
 182         return ret;
 183 }
 184
 185 int ldb_register_module(const struct ldb_module_ops *ops)
 186 {
 187         struct ops_list_entry *entry = talloc(talloc_autofree_context(), struct ops_list_entry);
 188
 189         if (ldb_find_module_ops(ops->name) != NULL)
 190                 return -1;
 191
 192         if (entry == NULL)
 193                 return -1;
 194
 195         entry->ops = ops;
 196         entry->next = registered_modules;
 197         registered_modules = entry;
 198
 199         return 0;
 200 }
 201
 202 int ldb_try_load_dso(struct ldb_context *ldb, const char *name)
 203 {
 204         char *path;
 205         void *handle;
 206         int (*init_fn) (void);
 207
 208 #ifdef HAVE_DLOPEN
 209 #ifdef _SAMBA_BUILD_
 210         path = talloc_asprintf(ldb, "%s/ldb/%s.%s", dyn_MODULESDIR, name, dyn_SHLIBEXT);
 211 #else
 212         path = talloc_asprintf(ldb, "%s/%s.%s", MODULESDIR, name, SHLIBEXT);
 213 #endif
 214
 215         ldb_debug(ldb, LDB_DEBUG_TRACE, "trying to load %s from %s\n", name, path);
 216
 217         handle = dlopen(path, 0);
 218         if (handle == NULL) {
 219                 ldb_debug(ldb, LDB_DEBUG_WARNING, "unable to load %s from %s: %s\n", name, path, dlerror());
 220                 return -1;
 221         }
 222
 223         init_fn = dlsym(handle, "init_module");
 224
 225         if (init_fn == NULL) {
 226                 ldb_debug(ldb, LDB_DEBUG_ERROR, "no symbol `init_module' found in %s: %s\n", path, dlerror());
 227                 return -1;
 228         }
 229
 230         talloc_free(path);
 231
 232         return init_fn();
 233 #else
 234         ldb_debug(ldb, LDB_DEBUG_TRACE, "no dlopen() - not trying to load %s module\n", name);
 235         return -1;
 236 #endif
 237 }
 238
 239 int ldb_load_modules(struct ldb_context *ldb, const char *options[])
 240 {
 241         const char **modules = NULL;
 242         struct ldb_module *module;
 243         int i;
 244         TALLOC_CTX *mem_ctx = talloc_new(ldb);
 245         if (!mem_ctx) {
 246                 return LDB_ERR_OPERATIONS_ERROR;
 247         }
 248
 249         /* find out which modules we are requested to activate */
 250
 251         /* check if we have a custom module list passd as ldb option */
 252         if (options) {
 253                 for (i = 0; options[i] != NULL; i++) {
 254                         if (strncmp(options[i], LDB_MODULE_PREFIX, LDB_MODULE_PREFIX_LEN) == 0) {
 255                                 modules = ldb_modules_list_from_string(ldb, mem_ctx, &options[i][LDB_MODULE_PREFIX_LEN]);
 256                         }
 257                 }
 258         }
 259
 260         /* if not overloaded by options and the backend is not ldap try to load the modules list from ldb */
 261         if ((modules == NULL) && (strcmp("ldap", ldb->modules->ops->name) != 0)) {
 262                 int ret;
 263                 const char * const attrs[] = { "@LIST" , NULL};
 264                 struct ldb_result *res;
 265                 struct ldb_dn *mods;
 266
 267                 mods = ldb_dn_explode(mem_ctx, "@MODULES");
 268                 if (mods == NULL) {
 269                         talloc_free(mem_ctx);
 270                         return -1;
 271                 }
 272
 273                 ret = ldb_search(ldb, mods, LDB_SCOPE_BASE, "", attrs, &res);
 274                 talloc_free(mods);
 275                 if (ret == LDB_SUCCESS && (res->count == 0 || res->msgs[0]->num_elements == 0)) {
 276                         ldb_debug(ldb, LDB_DEBUG_TRACE, "no modules required by the db\n");
 277                 } else {
 278                         if (ret != LDB_SUCCESS) {
 279                                 ldb_debug(ldb, LDB_DEBUG_FATAL, "ldb error (%s) occurred searching for modules, bailing out\n", ldb_errstring(ldb));
 280                                 talloc_free(mem_ctx);
 281                                 return -1;
 282                         }
 283                         if (res->count > 1) {
 284                                 ldb_debug(ldb, LDB_DEBUG_FATAL, "Too many records found (%d), bailing out\n", res->count);
 285                                 talloc_free(res);
 286                                 talloc_free(mem_ctx);
 287                                 return -1;
 288                         }
 289
 290                         modules = ldb_modules_list_from_string(ldb, mem_ctx,
 291                                                                (const char *)res->msgs[0]->elements[0].values[0].data);
 292
 293                         talloc_free(res);
 294                 }
 295         }
 296
 297         if (modules != NULL) {
 298                 for (i = 0; modules[i] != NULL; i++) {
 299                         struct ldb_module *current;
 300                         const struct ldb_module_ops *ops;
 301
 302                         ops = ldb_find_module_ops(modules[i]);
 303                         if (ops == NULL) {
 304                                 if (ldb_try_load_dso(ldb, modules[i]) == 0) {
 305                                         ops = ldb_find_module_ops(modules[i]);
 306                                 }
 307                         }
 308
 309                         if (ops == NULL) {
 310                                 ldb_debug(ldb, LDB_DEBUG_WARNING, "WARNING: Module [%s] not found\n",
 311                                           modules[i]);
 312                                 continue;
 313                         }
 314
 315                         current = talloc_zero(ldb, struct ldb_module);
 316                         if (current == NULL) {
 317                                 return -1;
 318                         }
 319
 320                         current->ldb = ldb;
 321                         current->ops = ops;
 322
 323                         DLIST_ADD(ldb->modules, current);
 324                 }
 325
 326                 talloc_free(modules);
 327         } else {
 328                 ldb_debug(ldb, LDB_DEBUG_TRACE, "No modules specified for this database\n");
 329         }
 330
 331         module = ldb->modules;
 332
 333         while (module && module->ops->init_context == NULL)
 334                 module = module->next;
 335
 336         if (module && module->ops->init_context &&
 337                 module->ops->init_context(module) != LDB_SUCCESS) {
 338                 ldb_debug(ldb, LDB_DEBUG_FATAL, "module initialization failed\n");
 339                 return -1;
 340         }
 341
 342         return 0;
 343 }
 344
 345 /*
 346   by using this we allow ldb modules to only implement the functions they care about,
 347   which makes writing a module simpler, and makes it more likely to keep working
 348   when ldb is extended
 349 */
 350 #define FIND_OP(module, op) do { \
 351         struct ldb_context *ldb = module->ldb; \
 352         module = module->next; \
 353         while (module && module->ops->op == NULL) module = module->next; \
 354         if (module == NULL) { \
 355                 ldb_set_errstring(ldb, talloc_strdup(ldb, "Unable to find backend operation for " #op )); \
 356                 return LDB_ERR_OPERATIONS_ERROR;        \
 357         }                                               \
 358 } while (0)
 359
 360
 361 /*
 362    helper functions to call the next module in chain
 363 */
 364
 365 int ldb_next_request(struct ldb_module *module, struct ldb_request *request)
 366 {
 367         switch (request->operation) {
 368         case LDB_SEARCH:
 369                 FIND_OP(module, search);
 370                 return module->ops->search(module, request);
 371         case LDB_ADD:
 372                 FIND_OP(module, add);
 373                 return module->ops->add(module, request);
 374         case LDB_MODIFY:
 375                 FIND_OP(module, modify);
 376                 return module->ops->modify(module, request);
 377         case LDB_DELETE:
 378                 FIND_OP(module, del);
 379                 return module->ops->del(module, request);
 380         case LDB_RENAME:
 381                 FIND_OP(module, rename);
 382                 return module->ops->rename(module, request);
 383         case LDB_SEQUENCE_NUMBER:
 384                 FIND_OP(module, sequence_number);
 385                 return module->ops->sequence_number(module, request);
 386         default:
 387                 FIND_OP(module, request);
 388                 return module->ops->request(module, request);
 389         }
 390 }
 391
 392 int ldb_next_init(struct ldb_module *module)
 393 {
 394         /* init is different in that it is not an error if modules
 395          * do not require initialization */
 396
 397         module = module->next;
 398
 399         while (module && module->ops->init_context == NULL)
 400                 module = module->next;
 401
 402         if (module == NULL)
 403                 return LDB_SUCCESS;
 404
 405         return module->ops->init_context(module);
 406 }
 407
 408 int ldb_next_start_trans(struct ldb_module *module)
 409 {
 410         FIND_OP(module, start_transaction);
 411         return module->ops->start_transaction(module);
 412 }
 413
 414 int ldb_next_end_trans(struct ldb_module *module)
 415 {
 416         FIND_OP(module, end_transaction);
 417         return module->ops->end_transaction(module);
 418 }
 419
 420 int ldb_next_del_trans(struct ldb_module *module)
 421 {
 422         FIND_OP(module, del_transaction);
 423         return module->ops->del_transaction(module);
 424 }