/* 
   Unix SMB/CIFS mplementation.

   The module that handles the Schema FSMO Role Owner
   checkings, it also loads the dsdb_schema.
   
   Copyright (C) Stefan Metzmacher <metze@samba.org> 2007
   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/>.
   
*/

#include "includes.h"
#include "ldb_module.h"
#include "dsdb/samdb/samdb.h"
#include "librpc/gen_ndr/ndr_misc.h"
#include "librpc/gen_ndr/ndr_drsuapi.h"
#include "librpc/gen_ndr/ndr_drsblobs.h"
#include "param/param.h"
#include "dsdb/samdb/ldb_modules/util.h"

static int generate_objectClasses(struct ldb_context *ldb, struct ldb_message *msg,
				  const struct dsdb_schema *schema);
static int generate_attributeTypes(struct ldb_context *ldb, struct ldb_message *msg,
				   const struct dsdb_schema *schema);
static int generate_dITContentRules(struct ldb_context *ldb, struct ldb_message *msg,
				    const struct dsdb_schema *schema);
static int generate_extendedAttributeInfo(struct ldb_context *ldb, struct ldb_message *msg,
					  const struct dsdb_schema *schema);
static int generate_extendedClassInfo(struct ldb_context *ldb, struct ldb_message *msg,
				      const struct dsdb_schema *schema);
static int generate_possibleInferiors(struct ldb_context *ldb, struct ldb_message *msg,
				      const struct dsdb_schema *schema);

static const struct {
	const char *attr;
	int (*fn)(struct ldb_context *, struct ldb_message *, const struct dsdb_schema *);
	bool aggregate;
} generated_attrs[] = {
	{
		.attr = "objectClasses",
		.fn = generate_objectClasses,
		.aggregate = true,
	},
	{
		.attr = "attributeTypes",
		.fn = generate_attributeTypes,
		.aggregate = true,
	},
	{
		.attr = "dITContentRules",
		.fn = generate_dITContentRules,
		.aggregate = true,
	},
	{
		.attr = "extendedAttributeInfo",
		.fn = generate_extendedAttributeInfo,
		.aggregate = true,
	},
	{
		.attr = "extendedClassInfo",
		.fn = generate_extendedClassInfo,
		.aggregate = true,
	},
	{
		.attr = "possibleInferiors",
		.fn = generate_possibleInferiors,
		.aggregate = false,
	}
};

struct schema_fsmo_private_data {
	struct ldb_dn *aggregate_dn;
};

struct schema_fsmo_search_data {
	struct ldb_module *module;
	struct ldb_request *req;

	const struct dsdb_schema *schema;
};

/*
  Given an LDB module (pointing at the schema DB), and the DN, set the populated schema
*/

static int dsdb_schema_from_schema_dn(TALLOC_CTX *mem_ctx, struct ldb_module *module,
				      struct smb_iconv_convenience *iconv_convenience, 
				      struct ldb_dn *schema_dn,
				      struct dsdb_schema **schema) 
{
	TALLOC_CTX *tmp_ctx;
	char *error_string;
	int ret;
	struct ldb_context *ldb = ldb_module_get_ctx(module);
	struct ldb_result *schema_res;
	struct ldb_result *a_res;
	struct ldb_result *c_res;
	static const char *schema_attrs[] = {
		"prefixMap",
		"schemaInfo",
		"fSMORoleOwner",
		NULL
	};
	unsigned flags;

	tmp_ctx = talloc_new(mem_ctx);
	if (!tmp_ctx) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}

	/* we don't want to trace the schema load */
	flags = ldb_get_flags(ldb);
	ldb_set_flags(ldb, flags & ~LDB_FLG_ENABLE_TRACING);

	/*
	 * setup the prefix mappings and schema info
	 */
	ret = dsdb_module_search_dn(module, tmp_ctx, &schema_res,
				    schema_dn, schema_attrs);
	if (ret == LDB_ERR_NO_SUCH_OBJECT) {
		goto failed;
	} else if (ret != LDB_SUCCESS) {
		ldb_asprintf_errstring(ldb, 
				       "dsdb_schema: failed to search the schema head: %s",
				       ldb_errstring(ldb));
		goto failed;
	}

	/*
	 * load the attribute definitions
	 */
	ret = dsdb_module_search(module, tmp_ctx, &a_res,
				 schema_dn, LDB_SCOPE_ONELEVEL, NULL,
				 "(objectClass=attributeSchema)");
	if (ret != LDB_SUCCESS) {
		ldb_asprintf_errstring(ldb, 
				       "dsdb_schema: failed to search attributeSchema objects: %s",
				       ldb_errstring(ldb));
		goto failed;
	}

	/*
	 * load the objectClass definitions
	 */
	ret = dsdb_module_search(module, tmp_ctx, &c_res,
				 schema_dn, LDB_SCOPE_ONELEVEL, NULL,
				 "(objectClass=classSchema)");
	if (ret != LDB_SUCCESS) {
		ldb_asprintf_errstring(ldb, 
				       "dsdb_schema: failed to search attributeSchema objects: %s",
				       ldb_errstring(ldb));
		goto failed;
	}

	ret = dsdb_schema_from_ldb_results(tmp_ctx, ldb,
					   lp_iconv_convenience(ldb_get_opaque(ldb, "loadparm")),
					   schema_res, a_res, c_res, schema, &error_string);
	if (ret != LDB_SUCCESS) {
		ldb_asprintf_errstring(ldb, 
						    "dsdb_schema load failed: %s",
						    error_string);
		goto failed;
	}
	talloc_steal(mem_ctx, *schema);

failed:
	if (flags & LDB_FLG_ENABLE_TRACING) {
		flags = ldb_get_flags(ldb);
		ldb_set_flags(ldb, flags | LDB_FLG_ENABLE_TRACING);
	}
	talloc_free(tmp_ctx);
	return ret;
}	


static int schema_fsmo_init(struct ldb_module *module)
{
	struct ldb_context *ldb;
	TALLOC_CTX *mem_ctx;
	struct ldb_dn *schema_dn;
	struct dsdb_schema *schema;
	int ret;
	struct schema_fsmo_private_data *data;

	ldb = ldb_module_get_ctx(module);
	schema_dn = samdb_schema_dn(ldb);
	if (!schema_dn) {
		ldb_reset_err_string(ldb);
		ldb_debug(ldb, LDB_DEBUG_WARNING,
			  "schema_fsmo_init: no schema dn present: (skip schema loading)\n");
		return ldb_next_init(module);
	}

	data = talloc(module, struct schema_fsmo_private_data);
	if (data == NULL) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}

	/* Check to see if this is a result on the CN=Aggregate schema */
	data->aggregate_dn = ldb_dn_copy(data, schema_dn);
	if (!ldb_dn_add_child_fmt(data->aggregate_dn, "CN=Aggregate")) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}

	ldb_module_set_private(module, data);

	if (dsdb_get_schema(ldb)) {
		return ldb_next_init(module);
	}

	mem_ctx = talloc_new(module);
	if (!mem_ctx) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}

	ret = dsdb_schema_from_schema_dn(mem_ctx, module,
					 lp_iconv_convenience(ldb_get_opaque(ldb, "loadparm")),
					 schema_dn, &schema);

	if (ret == LDB_ERR_NO_SUCH_OBJECT) {
		ldb_reset_err_string(ldb);
		ldb_debug(ldb, LDB_DEBUG_WARNING,
			  "schema_fsmo_init: no schema head present: (skip schema loading)\n");
		talloc_free(mem_ctx);
		return ldb_next_init(module);
	}

	if (ret != LDB_SUCCESS) {
		talloc_free(mem_ctx);
		return ret;
	}

	/* dsdb_set_schema() steal schema into the ldb_context */
	ret = dsdb_set_schema(ldb, schema);
	if (ret != LDB_SUCCESS) {
		ldb_debug_set(ldb, LDB_DEBUG_FATAL,
			      "schema_fsmo_init: dsdb_set_schema() failed: %d:%s",
			      ret, ldb_strerror(ret));
		talloc_free(mem_ctx);
		return ret;
	}

	talloc_free(mem_ctx);
	return ldb_next_init(module);
}

static int schema_fsmo_add(struct ldb_module *module, struct ldb_request *req)
{
	struct ldb_context *ldb;
	struct dsdb_schema *schema;
	const struct ldb_val *attributeID = NULL;
	const struct ldb_val *governsID = NULL;
	const char *oid_attr = NULL;
	const char *oid = NULL;
	uint32_t id32;
	WERROR status;

	ldb = ldb_module_get_ctx(module);

	/* special objects should always go through */
	if (ldb_dn_is_special(req->op.add.message->dn)) {
		return ldb_next_request(module, req);
	}

	/* replicated update should always go through */
	if (ldb_request_get_control(req, DSDB_CONTROL_REPLICATED_UPDATE_OID)) {
		return ldb_next_request(module, req);
	}

	schema = dsdb_get_schema(ldb);
	if (!schema) {
		return ldb_next_request(module, req);
	}

	if (!schema->fsmo.we_are_master) {
		ldb_debug_set(ldb, LDB_DEBUG_ERROR,
			  "schema_fsmo_add: we are not master: reject request\n");
		return LDB_ERR_UNWILLING_TO_PERFORM;
	}

	attributeID = ldb_msg_find_ldb_val(req->op.add.message, "attributeID");
	governsID = ldb_msg_find_ldb_val(req->op.add.message, "governsID");

	if (attributeID) {
		oid_attr = "attributeID";
		oid = talloc_strndup(req, (const char *)attributeID->data, attributeID->length);
	} else if (governsID) {
		oid_attr = "governsID";
		oid = talloc_strndup(req, (const char *)governsID->data, governsID->length);
	} else {
		return ldb_next_request(module, req);
	}

	if (!oid) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}
		
	status = dsdb_map_oid2int(schema, oid, &id32);
	if (W_ERROR_IS_OK(status)) {
		return ldb_next_request(module, req);
	} else if (!W_ERROR_EQUAL(WERR_DS_NO_MSDS_INTID, status)) {
		ldb_debug_set(ldb, LDB_DEBUG_ERROR,
			  "schema_fsmo_add: failed to map %s[%s]: %s\n",
			  oid_attr, oid, win_errstr(status));
		return LDB_ERR_UNWILLING_TO_PERFORM;
	}

	status = dsdb_create_prefix_mapping(ldb, schema, oid);
	if (!W_ERROR_IS_OK(status)) {
		ldb_debug_set(ldb, LDB_DEBUG_ERROR,
			  "schema_fsmo_add: failed to create prefix mapping for %s[%s]: %s\n",
			  oid_attr, oid, win_errstr(status));
		return LDB_ERR_UNWILLING_TO_PERFORM;
	}

	return ldb_next_request(module, req);
}

static int schema_fsmo_extended(struct ldb_module *module, struct ldb_request *req)
{
	struct ldb_context *ldb;
	struct ldb_dn *schema_dn;
	struct dsdb_schema *schema;
	int ret;
	TALLOC_CTX *mem_ctx;

	ldb = ldb_module_get_ctx(module);

	if (strcmp(req->op.extended.oid, DSDB_EXTENDED_SCHEMA_UPDATE_NOW_OID) != 0) {
		return ldb_next_request(module, req);
	}
	
	schema_dn = samdb_schema_dn(ldb);
	if (!schema_dn) {
		ldb_reset_err_string(ldb);
		ldb_debug(ldb, LDB_DEBUG_WARNING,
			  "schema_fsmo_extended: no schema dn present: (skip schema loading)\n");
		return ldb_next_request(module, req);
	}
	
	mem_ctx = talloc_new(module);
	if (!mem_ctx) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}
	
	ret = dsdb_schema_from_schema_dn(mem_ctx, module,
					 lp_iconv_convenience(ldb_get_opaque(ldb, "loadparm")),
					 schema_dn, &schema);

	if (ret == LDB_ERR_NO_SUCH_OBJECT) {
		ldb_reset_err_string(ldb);
		ldb_debug(ldb, LDB_DEBUG_WARNING,
			  "schema_fsmo_extended: no schema head present: (skip schema loading)\n");
		talloc_free(mem_ctx);
		return ldb_next_request(module, req);
	}

	if (ret != LDB_SUCCESS) {
		talloc_free(mem_ctx);
		return ldb_next_request(module, req);
	}

	/* Replace the old schema*/
	ret = dsdb_set_schema(ldb, schema);
	if (ret != LDB_SUCCESS) {
		ldb_debug_set(ldb, LDB_DEBUG_FATAL,
			      "schema_fsmo_extended: dsdb_set_schema() failed: %d:%s",
			      ret, ldb_strerror(ret));
		talloc_free(mem_ctx);
		return ret;
	}

	dsdb_make_schema_global(ldb);

	talloc_free(mem_ctx);
	return LDB_SUCCESS;
}

static int generate_objectClasses(struct ldb_context *ldb, struct ldb_message *msg,
				  const struct dsdb_schema *schema) 
{
	const struct dsdb_class *sclass;
	int ret;

	for (sclass = schema->classes; sclass; sclass = sclass->next) {
		ret = ldb_msg_add_string(msg, "objectClasses", schema_class_to_description(msg, sclass));
		if (ret != LDB_SUCCESS) {
			return ret;
		}
	}
	return LDB_SUCCESS;
}
static int generate_attributeTypes(struct ldb_context *ldb, struct ldb_message *msg,
				  const struct dsdb_schema *schema) 
{
	const struct dsdb_attribute *attribute;
	int ret;
	
	for (attribute = schema->attributes; attribute; attribute = attribute->next) {
		ret = ldb_msg_add_string(msg, "attributeTypes", schema_attribute_to_description(msg, attribute));
		if (ret != LDB_SUCCESS) {
			return ret;
		}
	}
	return LDB_SUCCESS;
}

static int generate_dITContentRules(struct ldb_context *ldb, struct ldb_message *msg,
				    const struct dsdb_schema *schema) 
{
	const struct dsdb_class *sclass;
	int ret;

	for (sclass = schema->classes; sclass; sclass = sclass->next) {
		if (sclass->auxiliaryClass || sclass->systemAuxiliaryClass) {
			char *ditcontentrule = schema_class_to_dITContentRule(msg, sclass, schema);
			if (!ditcontentrule) {
				ldb_oom(ldb);
				return LDB_ERR_OPERATIONS_ERROR;
			}
			ret = ldb_msg_add_steal_string(msg, "dITContentRules", ditcontentrule);
			if (ret != LDB_SUCCESS) {
				return ret;
			}
		}
	}
	return LDB_SUCCESS;
}

static int generate_extendedAttributeInfo(struct ldb_context *ldb,
					  struct ldb_message *msg,
					  const struct dsdb_schema *schema)
{
	const struct dsdb_attribute *attribute;
	int ret;

	for (attribute = schema->attributes; attribute; attribute = attribute->next) {
		char *val = schema_attribute_to_extendedInfo(msg, attribute);
		if (!val) {
			ldb_oom(ldb);
			return LDB_ERR_OPERATIONS_ERROR;
		}

		ret = ldb_msg_add_string(msg, "extendedAttributeInfo", val);
		if (ret != LDB_SUCCESS) {
			return ret;
		}
	}

	return LDB_SUCCESS;
}

static int generate_extendedClassInfo(struct ldb_context *ldb,
				      struct ldb_message *msg,
				      const struct dsdb_schema *schema)
{
	const struct dsdb_class *sclass;
	int ret;

	for (sclass = schema->classes; sclass; sclass = sclass->next) {
		char *val = schema_class_to_extendedInfo(msg, sclass);
		if (!val) {
			ldb_oom(ldb);
			return LDB_ERR_OPERATIONS_ERROR;
		}

		ret = ldb_msg_add_string(msg, "extendedClassInfo", val);
		if (ret != LDB_SUCCESS) {
			return ret;
		}
	}

	return LDB_SUCCESS;
}


static int generate_possibleInferiors(struct ldb_context *ldb, struct ldb_message *msg,
				      const struct dsdb_schema *schema) 
{
	struct ldb_dn *dn = msg->dn;
	int ret, i;
	const char *first_component_name = ldb_dn_get_component_name(dn, 0);
	const struct ldb_val *first_component_val;
	const struct dsdb_class *schema_class;
	const char **possibleInferiors;

	if (strcasecmp(first_component_name, "cn") != 0) {
		return LDB_SUCCESS;
	}

	first_component_val = ldb_dn_get_component_val(dn, 0);

	schema_class = dsdb_class_by_cn_ldb_val(schema, first_component_val);
	if (schema_class == NULL) {
		return LDB_SUCCESS;
	}
	
	possibleInferiors = schema_class->possibleInferiors;
	if (possibleInferiors == NULL) {
		return LDB_SUCCESS;
	}

	for (i=0;possibleInferiors[i];i++) {
		ret = ldb_msg_add_string(msg, "possibleInferiors", possibleInferiors[i]);
		if (ret != LDB_SUCCESS) {
			return ret;
		}
	}

	return LDB_SUCCESS;
}


/* Add objectClasses, attributeTypes and dITContentRules from the
   schema object (they are not stored in the database)
 */
static int schema_fsmo_search_callback(struct ldb_request *req, struct ldb_reply *ares)
{
	struct ldb_context *ldb;
	struct schema_fsmo_search_data *ac;
	struct schema_fsmo_private_data *mc;
	int i, ret;

	ac = talloc_get_type(req->context, struct schema_fsmo_search_data);
	mc = talloc_get_type(ldb_module_get_private(ac->module), struct schema_fsmo_private_data);
	ldb = ldb_module_get_ctx(ac->module);

	if (!ares) {
		return ldb_module_done(ac->req, NULL, NULL,
					LDB_ERR_OPERATIONS_ERROR);
	}
	if (ares->error != LDB_SUCCESS) {
		return ldb_module_done(ac->req, ares->controls,
					ares->response, ares->error);
	}
	/* Only entries are interesting, and we handle the case of the parent seperatly */

	switch (ares->type) {
	case LDB_REPLY_ENTRY:

		if (ldb_dn_compare(ares->message->dn, mc->aggregate_dn) == 0) {
			for (i=0; i < ARRAY_SIZE(generated_attrs); i++) {
				if (generated_attrs[i].aggregate &&
				    ldb_attr_in_list(ac->req->op.search.attrs, generated_attrs[i].attr)) {
					ret = generated_attrs[i].fn(ldb, ares->message, ac->schema);
					if (ret != LDB_SUCCESS) {
						return ret;
					}
				}
			}
		} else {
			for (i=0; i < ARRAY_SIZE(generated_attrs); i++) {
				if (!generated_attrs[i].aggregate &&
				    ldb_attr_in_list(ac->req->op.search.attrs, generated_attrs[i].attr)) {
					ret = generated_attrs[i].fn(ldb, ares->message, ac->schema);
					if (ret != LDB_SUCCESS) {
						return ret;
					}
				}
			}
		}


		return ldb_module_send_entry(ac->req, ares->message, ares->controls);

	case LDB_REPLY_REFERRAL:

		return ldb_module_send_referral(ac->req, ares->referral);

	case LDB_REPLY_DONE:

		return ldb_module_done(ac->req, ares->controls,
					ares->response, ares->error);
	}

	return LDB_SUCCESS;
}

/* search */
static int schema_fsmo_search(struct ldb_module *module, struct ldb_request *req)
{
	struct ldb_context *ldb = ldb_module_get_ctx(module);
	int i, ret;
	struct schema_fsmo_search_data *search_context;
	struct ldb_request *down_req;
	struct dsdb_schema *schema = dsdb_get_schema(ldb);

	if (!schema || !ldb_module_get_private(module)) {
		/* If there is no schema, there is little we can do */
		return ldb_next_request(module, req);
	}
	for (i=0; i < ARRAY_SIZE(generated_attrs); i++) {
		if (ldb_attr_in_list(req->op.search.attrs, generated_attrs[i].attr)) {
			break;
		}
	}
	if (i == ARRAY_SIZE(generated_attrs)) {
		/* No request for a generated attr found, nothing to
		 * see here, move along... */
		return ldb_next_request(module, req);
	}

	search_context = talloc(req, struct schema_fsmo_search_data);
	if (!search_context) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}

	search_context->module = module;
	search_context->req = req;
	search_context->schema = schema;

	ret = ldb_build_search_req_ex(&down_req, ldb, search_context,
					req->op.search.base,
					req->op.search.scope,
					req->op.search.tree,
					req->op.search.attrs,
					req->controls,
					search_context, schema_fsmo_search_callback,
					req);
	if (ret != LDB_SUCCESS) {
		return LDB_ERR_OPERATIONS_ERROR;
	}

	return ldb_next_request(module, down_req);
}


_PUBLIC_ const struct ldb_module_ops ldb_schema_fsmo_module_ops = {
	.name		= "schema_fsmo",
	.init_context	= schema_fsmo_init,
	.add		= schema_fsmo_add,
	.extended	= schema_fsmo_extended,
	.search         = schema_fsmo_search
};