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 #if (_SAMBA_BUILD_ >= 4)
  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 *ldb_modules_strdup_no_spaces(TALLOC_CTX *mem_ctx, const char *string)
  48 {
  49         int i, len;
  50         char *trimmed;
  51
  52         trimmed = talloc_strdup(mem_ctx, string);
  53         if (!trimmed) {
  54                 return NULL;
  55         }
  56
  57         len = strlen(trimmed);
  58         for (i = 0; trimmed[i] != '\0'; i++) {
  59                 switch (trimmed[i]) {
  60                 case ' ':
  61                 case '\t':
  62                 case '\n':
  63                         memmove(&trimmed[i], &trimmed[i + 1], len -i -1);
  64                         break;
  65                 }
  66         }
  67
  68         return trimmed;
  69 }
  70
  71
  72 /* modules are called in inverse order on the stack.
  73    Lets place them as an admin would think the right order is.
  74    Modules order is important */
  75 const char **ldb_modules_list_from_string(struct ldb_context *ldb, TALLOC_CTX *mem_ctx, const char *string)
  76 {
  77         char **modules = NULL;
  78         const char **m;
  79         char *modstr, *p;
  80         int i;
  81
  82         /* spaces not admitted */
  83         modstr = ldb_modules_strdup_no_spaces(mem_ctx, string);
  84         if ( ! modstr) {
  85                 ldb_debug(ldb, LDB_DEBUG_FATAL, "Out of Memory in ldb_modules_strdup_no_spaces()\n");
  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         /* The str*r*chr walks backwards:  This is how we get the inverse order mentioned above */
  99         while ((p = strrchr(modstr, ',')) != NULL) {
 100                 *p = '\0';
 101                 p++;
 102                 modules[i] = p;
 103
 104                 i++;
 105                 modules = talloc_realloc(mem_ctx, modules, char *, i + 2);
 106                 if ( ! modules ) {
 107                         ldb_debug(ldb, LDB_DEBUG_FATAL, "Out of Memory in ldb_modules_list_from_string()\n");
 108                         return NULL;
 109                 }
 110
 111         }
 112         modules[i] = modstr;
 113
 114         modules[i + 1] = NULL;
 115
 116         m = (const char **)modules;
 117
 118         return m;
 119 }
 120
 121 static struct ops_list_entry {
 122         const struct ldb_module_ops *ops;
 123         struct ops_list_entry *next;
 124 } *registered_modules = NULL;
 125
 126 static const struct ldb_module_ops *ldb_find_module_ops(const char *name)
 127 {
 128         struct ops_list_entry *e;
 129
 130         for (e = registered_modules; e; e = e->next) {
 131                 if (strcmp(e->ops->name, name) == 0)
 132                         return e->ops;
 133         }
 134
 135         return NULL;
 136 }
 137
 138 #ifndef STATIC_ldb_MODULES
 139
 140 #ifdef HAVE_LDB_LDAP
 141 #define LDAP_INIT ldb_ldap_init,
 142 #else
 143 #define LDAP_INIT
 144 #endif
 145
 146 #ifdef HAVE_LDB_SQLITE3
 147 #define SQLITE3_INIT ldb_sqlite3_init,
 148 #else
 149 #define SQLITE3_INIT
 150 #endif
 151
 152 #define STATIC_ldb_MODULES \
 153         {       \
 154                 LDAP_INIT \
 155                 SQLITE3_INIT \
 156                 ldb_tdb_init,   \
 157                 ldb_operational_init,   \
 158                 ldb_rdn_name_init,      \
 159                 ldb_objectclass_init,   \
 160                 ldb_paged_results_init, \
 161                 ldb_sort_init,          \
 162                 ldb_asq_init,           \
 163                 NULL                    \
 164         }
 165 #endif
 166
 167 int ldb_global_init(void)
 168 {
 169         static int (*static_init_fns[])(void) = STATIC_ldb_MODULES;
 170
 171         static int initialized = 0;
 172         int ret = 0, i;
 173
 174         if (initialized)
 175                 return 0;
 176
 177         initialized = 1;
 178
 179         for (i = 0; static_init_fns[i]; i++) {
 180                 if (static_init_fns[i]() == -1)
 181                         ret = -1;
 182         }
 183
 184         return ret;
 185 }
 186
 187 int ldb_register_module(const struct ldb_module_ops *ops)
 188 {
 189         struct ops_list_entry *entry = talloc(talloc_autofree_context(), struct ops_list_entry);
 190
 191         if (ldb_find_module_ops(ops->name) != NULL)
 192                 return -1;
 193
 194         if (entry == NULL)
 195                 return -1;
 196
 197         entry->ops = ops;
 198         entry->next = registered_modules;
 199         registered_modules = entry;
 200
 201         return 0;
 202 }
 203
 204 int ldb_try_load_dso(struct ldb_context *ldb, const char *name)
 205 {
 206         char *path;
 207         void *handle;
 208         int (*init_fn) (void);
 209         char *modulesdir;
 210
 211 #ifdef HAVE_DLOPEN
 212         if (getenv("LD_LDB_MODULE_PATH") != NULL) {
 213                 modulesdir = talloc_strdup(ldb, getenv("LD_LDB_MODULE_PATH"));
 214         } else {
 215 #ifdef _SAMBA_BUILD_
 216                 modulesdir = talloc_asprintf(ldb, "%s/ldb", dyn_MODULESDIR);
 217 #else
 218                 modulesdir = talloc_strdup(ldb, MODULESDIR);
 219 #endif
 220         }
 221
 222         path = talloc_asprintf(ldb, "%s/%s.%s", modulesdir, name, SHLIBEXT);
 223
 224         talloc_free(modulesdir);
 225
 226         ldb_debug(ldb, LDB_DEBUG_TRACE, "trying to load %s from %s\n", name, path);
 227
 228         handle = dlopen(path, RTLD_NOW);
 229         if (handle == NULL) {
 230                 ldb_debug(ldb, LDB_DEBUG_WARNING, "unable to load %s from %s: %s\n", name, path, dlerror());
 231                 return -1;
 232         }
 233
 234         init_fn = (int (*)(void))dlsym(handle, "init_module");
 235
 236         if (init_fn == NULL) {
 237                 ldb_debug(ldb, LDB_DEBUG_ERROR, "no symbol `init_module' found in %s: %s\n", path, dlerror());
 238                 return -1;
 239         }
 240
 241         talloc_free(path);
 242
 243         return init_fn();
 244 #else
 245         ldb_debug(ldb, LDB_DEBUG_TRACE, "no dlopen() - not trying to load %s module\n", name);
 246         return -1;
 247 #endif
 248 }
 249
 250 int ldb_load_modules_list(struct ldb_context *ldb, const char **module_list, struct ldb_module *backend, struct ldb_module **out)
 251 {
 252         struct ldb_module *module;
 253         int i;
 254
 255         module = backend;
 256
 257         for (i = 0; module_list[i] != NULL; i++) {
 258                 struct ldb_module *current;
 259                 const struct ldb_module_ops *ops;
 260
 261                 ops = ldb_find_module_ops(module_list[i]);
 262                 if (ops == NULL) {
 263                         if (ldb_try_load_dso(ldb, module_list[i]) == 0) {
 264                                 ops = ldb_find_module_ops(module_list[i]);
 265                         }
 266                 }
 267
 268                 if (ops == NULL) {
 269                         ldb_debug(ldb, LDB_DEBUG_WARNING, "WARNING: Module [%s] not found\n",
 270                                   module_list[i]);
 271                         continue;
 272                 }
 273
 274                 current = talloc_zero(ldb, struct ldb_module);
 275                 if (current == NULL) {
 276                         return LDB_ERR_OPERATIONS_ERROR;
 277                 }
 278                 talloc_set_name(current, "ldb_module: %s", module_list[i]);
 279
 280                 current->ldb = ldb;
 281                 current->ops = ops;
 282
 283                 DLIST_ADD(module, current);
 284         }
 285         *out = module;
 286         return LDB_SUCCESS;
 287 }
 288
 289 int ldb_init_module_chain(struct ldb_context *ldb, struct ldb_module *module)
 290 {
 291         while (module && module->ops->init_context == NULL)
 292                 module = module->next;
 293
 294         if (module && module->ops->init_context &&
 295                 module->ops->init_context(module) != LDB_SUCCESS) {
 296                 ldb_debug(ldb, LDB_DEBUG_FATAL, "module initialization failed\n");
 297                 return LDB_ERR_OPERATIONS_ERROR;
 298         }
 299
 300         return LDB_SUCCESS;
 301 }
 302
 303 int ldb_load_modules(struct ldb_context *ldb, const char *options[])
 304 {
 305         const char **modules = NULL;
 306         int i;
 307         int ret;
 308         TALLOC_CTX *mem_ctx = talloc_new(ldb);
 309         if (!mem_ctx) {
 310                 return LDB_ERR_OPERATIONS_ERROR;
 311         }
 312
 313         /* find out which modules we are requested to activate */
 314
 315         /* check if we have a custom module list passd as ldb option */
 316         if (options) {
 317                 for (i = 0; options[i] != NULL; i++) {
 318                         if (strncmp(options[i], LDB_MODULE_PREFIX, LDB_MODULE_PREFIX_LEN) == 0) {
 319                                 modules = ldb_modules_list_from_string(ldb, mem_ctx, &options[i][LDB_MODULE_PREFIX_LEN]);
 320                         }
 321                 }
 322         }
 323
 324         /* if not overloaded by options and the backend is not ldap try to load the modules list from ldb */
 325         if ((modules == NULL) && (strcmp("ldap", ldb->modules->ops->name) != 0)) {
 326                 const char * const attrs[] = { "@LIST" , NULL};
 327                 struct ldb_result *res = NULL;
 328                 struct ldb_dn *mods_dn;
 329
 330                 mods_dn = ldb_dn_explode(mem_ctx, "@MODULES");
 331                 if (mods_dn == NULL) {
 332                         talloc_free(mem_ctx);
 333                         return -1;
 334                 }
 335
 336                 ret = ldb_search(ldb, mods_dn, LDB_SCOPE_BASE, "", attrs, &res);
 337                 talloc_steal(mods_dn, res);
 338                 if (ret == LDB_SUCCESS && (res->count == 0 || res->msgs[0]->num_elements == 0)) {
 339                         ldb_debug(ldb, LDB_DEBUG_TRACE, "no modules required by the db\n");
 340                 } else {
 341                         if (ret != LDB_SUCCESS) {
 342                                 ldb_debug(ldb, LDB_DEBUG_FATAL, "ldb error (%s) occurred searching for modules, bailing out\n", ldb_errstring(ldb));
 343                                 talloc_free(mem_ctx);
 344                                 return -1;
 345                         }
 346                         if (res->count > 1) {
 347                                 ldb_debug(ldb, LDB_DEBUG_FATAL, "Too many records found (%d), bailing out\n", res->count);
 348                                 talloc_free(mem_ctx);
 349                                 return -1;
 350                         }
 351
 352                         modules = ldb_modules_list_from_string(ldb, mem_ctx,
 353                                                                (const char *)res->msgs[0]->elements[0].values[0].data);
 354
 355                 }
 356
 357                 talloc_free(mods_dn);
 358         }
 359
 360         if (modules != NULL) {
 361                 ret = ldb_load_modules_list(ldb, modules, ldb->modules, &ldb->modules);
 362                 talloc_free(modules);
 363                 if (ret != LDB_SUCCESS) {
 364                         return ret;
 365                 }
 366         } else {
 367                 ldb_debug(ldb, LDB_DEBUG_TRACE, "No modules specified for this database\n");
 368         }
 369
 370         return ldb_init_module_chain(ldb, ldb->modules);
 371 }
 372
 373 /*
 374   by using this we allow ldb modules to only implement the functions they care about,
 375   which makes writing a module simpler, and makes it more likely to keep working
 376   when ldb is extended
 377 */
 378 #define FIND_OP(module, op) do { \
 379         struct ldb_context *ldb = module->ldb; \
 380         module = module->next; \
 381         while (module && module->ops->op == NULL) module = module->next; \
 382         if (module == NULL) { \
 383                 ldb_asprintf_errstring(ldb, "Unable to find backend operation for " #op ); \
 384                 return LDB_ERR_OPERATIONS_ERROR;        \
 385         }                                               \
 386 } while (0)
 387
 388
 389 /*
 390    helper functions to call the next module in chain
 391 */
 392
 393 int ldb_next_request(struct ldb_module *module, struct ldb_request *request)
 394 {
 395         switch (request->operation) {
 396         case LDB_SEARCH:
 397                 FIND_OP(module, search);
 398                 return module->ops->search(module, request);
 399         case LDB_ADD:
 400                 FIND_OP(module, add);
 401                 return module->ops->add(module, request);
 402         case LDB_MODIFY:
 403                 FIND_OP(module, modify);
 404                 return module->ops->modify(module, request);
 405         case LDB_DELETE:
 406                 FIND_OP(module, del);
 407                 return module->ops->del(module, request);
 408         case LDB_RENAME:
 409                 FIND_OP(module, rename);
 410                 return module->ops->rename(module, request);
 411         case LDB_SEQUENCE_NUMBER:
 412                 FIND_OP(module, sequence_number);
 413                 return module->ops->sequence_number(module, request);
 414         default:
 415                 FIND_OP(module, request);
 416                 return module->ops->request(module, request);
 417         }
 418 }
 419
 420 int ldb_next_init(struct ldb_module *module)
 421 {
 422         /* init is different in that it is not an error if modules
 423          * do not require initialization */
 424
 425         module = module->next;
 426
 427         while (module && module->ops->init_context == NULL)
 428                 module = module->next;
 429
 430         if (module == NULL)
 431                 return LDB_SUCCESS;
 432
 433         return module->ops->init_context(module);
 434 }
 435
 436 int ldb_next_start_trans(struct ldb_module *module)
 437 {
 438         FIND_OP(module, start_transaction);
 439         return module->ops->start_transaction(module);
 440 }
 441
 442 int ldb_next_end_trans(struct ldb_module *module)
 443 {
 444         FIND_OP(module, end_transaction);
 445         return module->ops->end_transaction(module);
 446 }
 447
 448 int ldb_next_del_trans(struct ldb_module *module)
 449 {
 450         FIND_OP(module, del_transaction);
 451         return module->ops->del_transaction(module);
 452 }