4 Copyright (C) Simo Sorce 2004
6 ** NOTE! The following LGPL license applies to the ldb
7 ** library. This does NOT imply that all of Samba is released
10 This library is free software; you can redistribute it and/or
11 modify it under the terms of the GNU Lesser General Public
12 License as published by the Free Software Foundation; either
13 version 3 of the License, or (at your option) any later version.
15 This library is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 Lesser General Public License for more details.
20 You should have received a copy of the GNU Lesser General Public
21 License along with this library; if not, see <http://www.gnu.org/licenses/>.
27 * Component: ldb modules core
29 * Description: core modules routines
34 #include "ldb_includes.h"
36 #if (_SAMBA_BUILD_ >= 4)
41 #define LDB_MODULE_PREFIX "modules:"
42 #define LDB_MODULE_PREFIX_LEN 8
44 void ldb_set_modules_dir(struct ldb_context *ldb, const char *path)
46 talloc_free(ldb->modules_dir);
47 ldb->modules_dir = talloc_strdup(ldb, path);
50 static char *ldb_modules_strdup_no_spaces(TALLOC_CTX *mem_ctx, const char *string)
55 trimmed = talloc_strdup(mem_ctx, string);
60 len = strlen(trimmed);
61 for (i = 0; trimmed[i] != '\0'; i++) {
66 memmove(&trimmed[i], &trimmed[i + 1], len -i -1);
75 /* modules are called in inverse order on the stack.
76 Lets place them as an admin would think the right order is.
77 Modules order is important */
78 const char **ldb_modules_list_from_string(struct ldb_context *ldb, TALLOC_CTX *mem_ctx, const char *string)
80 char **modules = NULL;
85 /* spaces not admitted */
86 modstr = ldb_modules_strdup_no_spaces(mem_ctx, string);
88 ldb_debug(ldb, LDB_DEBUG_FATAL, "Out of Memory in ldb_modules_strdup_no_spaces()\n");
92 modules = talloc_realloc(mem_ctx, modules, char *, 2);
94 ldb_debug(ldb, LDB_DEBUG_FATAL, "Out of Memory in ldb_modules_list_from_string()\n");
98 talloc_steal(modules, modstr);
101 /* The str*r*chr walks backwards: This is how we get the inverse order mentioned above */
102 while ((p = strrchr(modstr, ',')) != NULL) {
108 modules = talloc_realloc(mem_ctx, modules, char *, i + 2);
110 ldb_debug(ldb, LDB_DEBUG_FATAL, "Out of Memory in ldb_modules_list_from_string()\n");
117 modules[i + 1] = NULL;
119 m = (const char **)modules;
124 static struct ops_list_entry {
125 const struct ldb_module_ops *ops;
126 struct ops_list_entry *next;
127 } *registered_modules = NULL;
129 #ifndef STATIC_LIBLDB_MODULES
131 #define STATIC_LIBLDB_MODULES \
132 ldb_operational_module_ops, \
133 ldb_rdn_name_module_ops, \
134 ldb_paged_results_module_ops, \
135 ldb_sort_module_ops, \
136 ldb_asq_module_ops, \
140 const static struct ldb_module_ops *builtin_modules[] = {
141 STATIC_LIBLDB_MODULES
144 static const struct ldb_module_ops *ldb_find_module_ops(const char *name)
146 struct ops_list_entry *e;
149 for (i = 0; builtin_modules[i]; i++) {
150 if (strcmp(builtin_modules[i]->name, name) == 0)
151 return builtin_modules[i];
154 for (e = registered_modules; e; e = e->next) {
155 if (strcmp(e->ops->name, name) == 0)
163 int ldb_register_module(const struct ldb_module_ops *ops)
165 struct ops_list_entry *entry = talloc(talloc_autofree_context(), struct ops_list_entry);
167 if (ldb_find_module_ops(ops->name) != NULL)
174 entry->next = registered_modules;
175 registered_modules = entry;
180 void *ldb_dso_load_symbol(struct ldb_context *ldb, const char *name,
187 if (ldb->modules_dir == NULL)
190 path = talloc_asprintf(ldb, "%s/%s.%s", ldb->modules_dir, name,
193 ldb_debug(ldb, LDB_DEBUG_TRACE, "trying to load %s from %s\n", name, path);
195 handle = dlopen(path, RTLD_NOW);
196 if (handle == NULL) {
197 ldb_debug(ldb, LDB_DEBUG_WARNING, "unable to load %s from %s: %s\n", name, path, dlerror());
201 sym = (int (*)(void))dlsym(handle, symbol);
204 ldb_debug(ldb, LDB_DEBUG_ERROR, "no symbol `%s' found in %s: %s\n", symbol, path, dlerror());
213 int ldb_load_modules_list(struct ldb_context *ldb, const char **module_list, struct ldb_module *backend, struct ldb_module **out)
215 struct ldb_module *module;
220 for (i = 0; module_list[i] != NULL; i++) {
221 struct ldb_module *current;
222 const struct ldb_module_ops *ops;
224 ops = ldb_find_module_ops(module_list[i]);
226 int (*init_fn) (void);
228 init_fn = ldb_dso_load_symbol(ldb, module_list[i],
230 if (init_fn != NULL && init_fn() == 0) {
231 ops = ldb_find_module_ops(module_list[i]);
236 char *symbol_name = talloc_asprintf(ldb, "ldb_%s_module_ops",
238 if (symbol_name == NULL) {
239 return LDB_ERR_OPERATIONS_ERROR;
241 ops = ldb_dso_load_symbol(ldb, module_list[i], symbol_name);
242 talloc_free(symbol_name);
246 ldb_debug(ldb, LDB_DEBUG_WARNING, "WARNING: Module [%s] not found\n",
251 current = talloc_zero(ldb, struct ldb_module);
252 if (current == NULL) {
253 return LDB_ERR_OPERATIONS_ERROR;
255 talloc_set_name(current, "ldb_module: %s", module_list[i]);
260 DLIST_ADD(module, current);
266 int ldb_init_module_chain(struct ldb_context *ldb, struct ldb_module *module)
268 while (module && module->ops->init_context == NULL)
269 module = module->next;
271 /* init is different in that it is not an error if modules
272 * do not require initialization */
275 int ret = module->ops->init_context(module);
276 if (ret != LDB_SUCCESS) {
277 ldb_debug(ldb, LDB_DEBUG_FATAL, "module %s initialization failed\n", module->ops->name);
285 int ldb_load_modules(struct ldb_context *ldb, const char *options[])
287 const char **modules = NULL;
290 TALLOC_CTX *mem_ctx = talloc_new(ldb);
292 return LDB_ERR_OPERATIONS_ERROR;
295 /* find out which modules we are requested to activate */
297 /* check if we have a custom module list passd as ldb option */
299 for (i = 0; options[i] != NULL; i++) {
300 if (strncmp(options[i], LDB_MODULE_PREFIX, LDB_MODULE_PREFIX_LEN) == 0) {
301 modules = ldb_modules_list_from_string(ldb, mem_ctx, &options[i][LDB_MODULE_PREFIX_LEN]);
306 /* if not overloaded by options and the backend is not ldap try to load the modules list from ldb */
307 if ((modules == NULL) && (strcmp("ldap", ldb->modules->ops->name) != 0)) {
308 const char * const attrs[] = { "@LIST" , NULL};
309 struct ldb_result *res = NULL;
310 struct ldb_dn *mods_dn;
312 mods_dn = ldb_dn_new(mem_ctx, ldb, "@MODULES");
313 if (mods_dn == NULL) {
314 talloc_free(mem_ctx);
318 ret = ldb_search_exp_fmt(ldb, mods_dn, &res, mods_dn, LDB_SCOPE_BASE, attrs, "@LIST=*");
320 if (ret == LDB_ERR_NO_SUCH_OBJECT) {
321 ldb_debug(ldb, LDB_DEBUG_TRACE, "no modules required by the db");
322 } else if (ret != LDB_SUCCESS) {
323 ldb_debug(ldb, LDB_DEBUG_FATAL, "ldb error (%s) occurred searching for modules, bailing out\n", ldb_errstring(ldb));
324 talloc_free(mem_ctx);
327 const char *module_list;
328 if (res->count == 0) {
329 ldb_debug(ldb, LDB_DEBUG_TRACE, "no modules required by the db");
330 } else if (res->count > 1) {
331 ldb_debug(ldb, LDB_DEBUG_FATAL, "Too many records found (%d), bailing out\n", res->count);
332 talloc_free(mem_ctx);
335 module_list = ldb_msg_find_attr_as_string(res->msgs[0], "@LIST", NULL);
337 ldb_debug(ldb, LDB_DEBUG_TRACE, "no modules required by the db");
339 modules = ldb_modules_list_from_string(ldb, mem_ctx,
344 talloc_free(mods_dn);
347 if (modules != NULL) {
348 ret = ldb_load_modules_list(ldb, modules, ldb->modules, &ldb->modules);
349 if (ret != LDB_SUCCESS) {
350 talloc_free(mem_ctx);
354 ldb_debug(ldb, LDB_DEBUG_TRACE, "No modules specified for this database");
357 ret = ldb_init_module_chain(ldb, ldb->modules);
358 talloc_free(mem_ctx);
363 by using this we allow ldb modules to only implement the functions they care about,
364 which makes writing a module simpler, and makes it more likely to keep working
367 #define FIND_OP(module, op) do { \
368 struct ldb_context *ldb = module->ldb; \
369 module = module->next; \
370 while (module && module->ops->op == NULL) module = module->next; \
371 if (module == NULL) { \
372 ldb_asprintf_errstring(ldb, "Unable to find backend operation for " #op ); \
373 return LDB_ERR_OPERATIONS_ERROR; \
379 helper functions to call the next module in chain
382 int ldb_next_request(struct ldb_module *module, struct ldb_request *request)
385 switch (request->operation) {
387 FIND_OP(module, search);
388 ret = module->ops->search(module, request);
391 FIND_OP(module, add);
392 ret = module->ops->add(module, request);
395 FIND_OP(module, modify);
396 ret = module->ops->modify(module, request);
399 FIND_OP(module, del);
400 ret = module->ops->del(module, request);
403 FIND_OP(module, rename);
404 ret = module->ops->rename(module, request);
407 FIND_OP(module, extended);
408 ret = module->ops->extended(module, request);
410 case LDB_SEQUENCE_NUMBER:
411 FIND_OP(module, sequence_number);
412 ret = module->ops->sequence_number(module, request);
415 FIND_OP(module, request);
416 ret = module->ops->request(module, request);
419 if (ret == LDB_SUCCESS) {
422 if (!ldb_errstring(module->ldb)) {
423 /* Set a default error string, to place the blame somewhere */
424 ldb_asprintf_errstring(module->ldb, "error in module %s: %s (%d)", module->ops->name, ldb_strerror(ret), ret);
429 int ldb_next_init(struct ldb_module *module)
431 module = module->next;
433 return ldb_init_module_chain(module->ldb, module);
436 int ldb_next_start_trans(struct ldb_module *module)
438 FIND_OP(module, start_transaction);
439 return module->ops->start_transaction(module);
442 int ldb_next_end_trans(struct ldb_module *module)
444 FIND_OP(module, end_transaction);
445 return module->ops->end_transaction(module);
448 int ldb_next_del_trans(struct ldb_module *module)
450 FIND_OP(module, del_transaction);
451 return module->ops->del_transaction(module);