text: /*
     Samba4 module loading module
  
     Copyright (C) Andrew Bartlett <abartlet@samba.org> 2009
  
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
  
  /*
   *  Name: ldb
   *
   *  Component: Samba4 module loading module
   *
   *  Description: Implement a single 'module' in the ldb database,
   *  which loads the remaining modules based on 'choice of configuration' attributes
   *
   *  This is to avoid forcing a reprovision of the ldb databases when we change the internal structure of the code
   *
   *  Author: Andrew Bartlett
   */
  
  #include "includes.h"
  #include <ldb.h>
  #include <ldb_errors.h>
  #include <ldb_module.h>
  #include "dsdb/samdb/ldb_modules/util.h"
  #include "dsdb/samdb/samdb.h"
  #include "librpc/ndr/libndr.h"
  
  static int read_at_rootdse_record(struct ldb_context *ldb, struct ldb_module *module, TALLOC_CTX *mem_ctx,
  				  struct ldb_message **msg, struct ldb_request *parent)
  {
  	int ret;
  	static const char *rootdse_attrs[] = { "defaultNamingContext", "configurationNamingContext", "schemaNamingContext", NULL };
  	struct ldb_result *rootdse_res;
  	struct ldb_dn *rootdse_dn;
  	TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
  	if (!tmp_ctx) {
  		return ldb_oom(ldb);
  	}
  
  	rootdse_dn = ldb_dn_new(tmp_ctx, ldb, "@ROOTDSE");
  	if (!rootdse_dn) {
  		talloc_free(tmp_ctx);
  		return ldb_oom(ldb);
  	}
  
  	ret = dsdb_module_search_dn(module, tmp_ctx, &rootdse_res, rootdse_dn,
  	                            rootdse_attrs, DSDB_FLAG_NEXT_MODULE, parent);
  	if (ret != LDB_SUCCESS) {
  		talloc_free(tmp_ctx);
  		return ret;
  	}
  
  	talloc_steal(mem_ctx, rootdse_res->msgs);
  	*msg = rootdse_res->msgs[0];
  
  	talloc_free(tmp_ctx);
  
  	return ret;
  }
  
  static int prepare_modules_line(struct ldb_context *ldb,
  				TALLOC_CTX *mem_ctx,
  				const struct ldb_message *rootdse_msg,
  				struct ldb_message *msg, const char *backend_attr,
  				const char *backend_mod, const char **backend_mod_list)
  {
  	int ret;
  	const char **backend_full_list;
  	const char *backend_dn;
  	char *mod_list_string;
  	char *full_string;
  	TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
  	if (!tmp_ctx) {
  		return ldb_oom(ldb);
  	}
  
  	if (backend_attr) {
  		backend_dn = ldb_msg_find_attr_as_string(rootdse_msg, backend_attr, NULL);
  		if (!backend_dn) {
  			ldb_asprintf_errstring(ldb,
  					       "samba_dsdb_init: "
  					       "unable to read %s from %s:%s",
  					       backend_attr, ldb_dn_get_linearized(rootdse_msg->dn),
  					       ldb_errstring(ldb));
  			return LDB_ERR_CONSTRAINT_VIOLATION;
  		}
  	} else {
  		backend_dn = "*";
  	}
  
  	if (backend_mod) {
  		backend_full_list = (const char **)str_list_make_single(tmp_ctx, backend_mod);
  	} else {
  		backend_full_list = (const char **)str_list_make_empty(tmp_ctx);
  	}
  	if (!backend_full_list) {
  		talloc_free(tmp_ctx);
  		return ldb_oom(ldb);
  	}
  
  	backend_full_list = str_list_append_const(backend_full_list, backend_mod_list);
  	if (!backend_full_list) {
  		talloc_free(tmp_ctx);
  		return ldb_oom(ldb);
  	}
  
  	mod_list_string = str_list_join(tmp_ctx, backend_full_list, ',');
  	if (!mod_list_string) {
  		talloc_free(tmp_ctx);
  		return ldb_oom(ldb);
  	}
  
  	full_string = talloc_asprintf(tmp_ctx, "%s:%s", backend_dn, mod_list_string);
  	ret = ldb_msg_add_steal_string(msg, "modules", full_string);
  	talloc_free(tmp_ctx);
  	return ret;
  }
  
  
  
  static int samba_dsdb_init(struct ldb_module *module)
  {
  	struct ldb_context *ldb = ldb_module_get_ctx(module);
  	int ret, len, i;
  	TALLOC_CTX *tmp_ctx = talloc_new(module);
  	struct ldb_result *res;
  	struct ldb_message *rootdse_msg, *partition_msg;
  	struct ldb_dn *samba_dsdb_dn;
  	struct ldb_module *backend_module, *module_chain;
  	const char **final_module_list, **reverse_module_list;
  	/*
  	  Add modules to the list to activate them by default
  	  beware often order is important
  
  	  Some Known ordering constraints:
  	  - rootdse must be first, as it makes redirects from "" -> cn=rootdse
  	  - extended_dn_in must be before objectclass.c, as it resolves the DN
  	  - objectclass must be before password_hash and samldb since these LDB
  	    modules require the expanded "objectClass" list
  	  - objectclass_attrs must be behind operational in order to see all
  	    attributes (the operational module protects and therefore
  	    suppresses per default some important ones)
  	  - partition must be last
  	  - each partition has its own module list then
  
  	  The list is presented here as a set of declarations to show the
  	  stack visually - the code below then handles the creation of the list
  	  based on the parameters loaded from the database.
  	*/
  	static const char *modules_list[] = {"resolve_oids",
  					     "rootdse",
  					     "lazy_commit",
  					     "paged_results",
  					     "ranged_results",
  					     "anr",
  					     "server_sort",
  					     "asq",
  					     "extended_dn_store",
  					     "extended_dn_in",
  					     "objectclass",
  					     "descriptor",
  					     "acl",
  					     "aclread",
  					     "samldb",
  					     "password_hash",
  					     "operational",
  					     "schema_load",
  					     "instancetype",
  					     "objectclass_attrs",
  					     NULL };
  
  	const char **link_modules;
  	static const char *fedora_ds_modules[] = {
  		"rdn_name", NULL };
  	static const char *openldap_modules[] = {
  		NULL };
  	static const char *tdb_modules_list[] = {
  		"rdn_name",
  		"subtree_delete",
  		"repl_meta_data",
  		"subtree_rename",
  		"linked_attributes",
  		NULL};
  
  	const char *extended_dn_module;
  	const char *extended_dn_module_ldb = "extended_dn_out_ldb";
  	const char *extended_dn_module_fds = "extended_dn_out_fds";
  	const char *extended_dn_module_openldap = "extended_dn_out_openldap";
  
  	static const char *modules_list2[] = {"show_deleted",
  					      "new_partition",
  					      "partition",
  					      NULL };
  
  	const char **backend_modules;
  	static const char *fedora_ds_backend_modules[] = {
  		"nsuniqueid", "paged_searches", "simple_dn", NULL };
  	static const char *openldap_backend_modules[] = {
  		"entryuuid", "paged_searches", "simple_dn", NULL };
  
  	static const char *samba_dsdb_attrs[] = { "backendType", "serverRole", NULL };
  	const char *backendType, *serverRole;
  
  	if (!tmp_ctx) {
  		return ldb_oom(ldb);
  	}
  
  	ret = ldb_register_samba_handlers(ldb);
  	if (ret != LDB_SUCCESS) {
  		talloc_free(tmp_ctx);
  		return ret;
  	}
  
  	samba_dsdb_dn = ldb_dn_new(tmp_ctx, ldb, "@SAMBA_DSDB");
  	if (!samba_dsdb_dn) {
  		talloc_free(tmp_ctx);
  		return ldb_oom(ldb);
  	}
  
  #define CHECK_LDB_RET(check_ret)				\
  	do {							\
  		if (check_ret != LDB_SUCCESS) {			\
  			talloc_free(tmp_ctx);			\
  			return check_ret;			\
  		}						\
  	} while (0)
  
  	ret = dsdb_module_search_dn(module, tmp_ctx, &res, samba_dsdb_dn,
  	                            samba_dsdb_attrs, DSDB_FLAG_NEXT_MODULE, NULL);
  	if (ret == LDB_ERR_NO_SUCH_OBJECT) {
  		backendType = "ldb";
  		serverRole = "domain controller";
  	} else if (ret == LDB_SUCCESS) {
  		backendType = ldb_msg_find_attr_as_string(res->msgs[0], "backendType", "ldb");
  		serverRole = ldb_msg_find_attr_as_string(res->msgs[0], "serverRole", "domain controller");
  	} else {
  		talloc_free(tmp_ctx);
  		return ret;
  	}
  
  	backend_modules = NULL;
  	if (strcasecmp(backendType, "ldb") == 0) {
  		extended_dn_module = extended_dn_module_ldb;
  		link_modules = tdb_modules_list;
  	} else {
  		if (strcasecmp(backendType, "fedora-ds") == 0) {
  			link_modules = fedora_ds_modules;
  			backend_modules = fedora_ds_backend_modules;
  			extended_dn_module = extended_dn_module_fds;
  		} else if (strcasecmp(backendType, "openldap") == 0) {
  			link_modules = openldap_modules;
  			backend_modules = openldap_backend_modules;
  			extended_dn_module = extended_dn_module_openldap;
  		} else {
  			return ldb_error(ldb, LDB_ERR_OPERATIONS_ERROR, "invalid backend type");
  		}
  		ret = ldb_set_opaque(ldb, "readOnlySchema", (void*)1);
  		if (ret != LDB_SUCCESS) {
  			ldb_set_errstring(ldb, "Failed to set readOnlySchema opaque");
  		}
  	}
  
  #define CHECK_MODULE_LIST \
  	do {							\
  		if (!final_module_list) {			\
  			talloc_free(tmp_ctx);			\
  			return ldb_oom(ldb);			\
  		}						\
  	} while (0)
  
  	final_module_list = str_list_copy_const(tmp_ctx, modules_list);
  	CHECK_MODULE_LIST;
  
  	final_module_list = str_list_append_const(final_module_list, link_modules);
  	CHECK_MODULE_LIST;
  
  	final_module_list = str_list_add_const(final_module_list, extended_dn_module);
  	CHECK_MODULE_LIST;
  
  	final_module_list = str_list_append_const(final_module_list, modules_list2);
  	CHECK_MODULE_LIST;
  
  
  	ret = read_at_rootdse_record(ldb, module, tmp_ctx, &rootdse_msg, NULL);
  	CHECK_LDB_RET(ret);
  
  	partition_msg = ldb_msg_new(tmp_ctx);
  	partition_msg->dn = ldb_dn_new(partition_msg, ldb, "@" DSDB_OPAQUE_PARTITION_MODULE_MSG_OPAQUE_NAME);
  
  	ret = prepare_modules_line(ldb, tmp_ctx,
  				   rootdse_msg,
  				   partition_msg, "defaultNamingContext",
  				   "pdc_fsmo", backend_modules);
  	CHECK_LDB_RET(ret);
  
  	ret = prepare_modules_line(ldb, tmp_ctx,
  				   rootdse_msg,
  				   partition_msg, "configurationNamingContext",
  				   "naming_fsmo", backend_modules);
  	CHECK_LDB_RET(ret);
  
  	ret = prepare_modules_line(ldb, tmp_ctx,
  				   rootdse_msg,
  				   partition_msg, "schemaNamingContext",
  				   "schema_data", backend_modules);
  	CHECK_LDB_RET(ret);
  
  	ret = prepare_modules_line(ldb, tmp_ctx,
  				   rootdse_msg,
  				   partition_msg, NULL,
  				   NULL, backend_modules);
  	CHECK_LDB_RET(ret);
  
  	ret = ldb_set_opaque(ldb, DSDB_OPAQUE_PARTITION_MODULE_MSG_OPAQUE_NAME, partition_msg);
  	CHECK_LDB_RET(ret);
  
  	talloc_steal(ldb, partition_msg);
  
  	/* Now prepare the module chain.  Oddly, we must give it to ldb_load_modules_list in REVERSE */
  	for (len = 0; final_module_list[len]; len++) { /* noop */};
  
  	reverse_module_list = talloc_array(tmp_ctx, const char *, len+1);
  	if (!reverse_module_list) {
  		talloc_free(tmp_ctx);
  		return ldb_oom(ldb);
  	}
  	for (i=0; i < len; i++) {
  		reverse_module_list[i] = final_module_list[(len - 1) - i];
  	}
  	reverse_module_list[i] = NULL;
  
  	/* The backend (at least until the partitions module
  	 * reconfigures things) is the next module in the currently
  	 * loaded chain */
  	backend_module = ldb_module_next(module);
  	ret = ldb_module_load_list(ldb, reverse_module_list, backend_module, &module_chain);
  	CHECK_LDB_RET(ret);
  
  	talloc_free(tmp_ctx);
  	/* Set this as the 'next' module, so that we effectivly append it to module chain */
  	ldb_module_set_next(module, module_chain);
  
  	return ldb_next_init(module);
  }
  
  static const struct ldb_module_ops ldb_samba_dsdb_module_ops = {
  	.name		   = "samba_dsdb",
  	.init_context	   = samba_dsdb_init,
  };
  
  int ldb_samba_dsdb_module_init(const char *version)
  {
  	LDB_MODULE_CHECK_VERSION(version);
  	return ldb_register_module(&ldb_samba_dsdb_module_ops);
  }
  