/* 
   Unix SMB/CIFS mplementation.
   DSDB schema header
   
   Copyright (C) Stefan Metzmacher <metze@samba.org> 2006-2007
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2006-2008

   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 "lib/util/dlinklist.h"
#include "dsdb/samdb/samdb.h"
#include "lib/ldb/include/ldb_module.h"
#include "param/param.h"
#include "librpc/ndr/libndr.h"
#include "librpc/gen_ndr/ndr_misc.h"
#include "lib/util/tsort.h"

/*
  override the name to attribute handler function
 */
const struct ldb_schema_attribute *dsdb_attribute_handler_override(struct ldb_context *ldb, 
								   void *private_data,
								   const char *name)
{
	struct dsdb_schema *schema = talloc_get_type_abort(private_data, struct dsdb_schema);
	const struct dsdb_attribute *a = dsdb_attribute_by_lDAPDisplayName(schema, name);
	if (a == NULL) {
		/* this will fall back to ldb internal handling */
		return NULL;
	}
	return a->ldb_schema_attribute;
}

static int dsdb_schema_set_attributes(struct ldb_context *ldb, struct dsdb_schema *schema, bool write_attributes)
{
	int ret = LDB_SUCCESS;
	struct ldb_result *res;
	struct ldb_result *res_idx;
	struct dsdb_attribute *attr;
	struct ldb_message *mod_msg;
	TALLOC_CTX *mem_ctx;
	struct ldb_message *msg;
	struct ldb_message *msg_idx;

	/* setup our own attribute name to schema handler */
	ldb_schema_attribute_set_override_handler(ldb, dsdb_attribute_handler_override, schema);

	if (!write_attributes) {
		return ret;
	}

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

	msg = ldb_msg_new(mem_ctx);
	if (!msg) {
		ldb_oom(ldb);
		goto op_error;
	}
	msg_idx = ldb_msg_new(mem_ctx);
	if (!msg_idx) {
		ldb_oom(ldb);
		goto op_error;
	}
	msg->dn = ldb_dn_new(msg, ldb, "@ATTRIBUTES");
	if (!msg->dn) {
		ldb_oom(ldb);
		goto op_error;
	}
	msg_idx->dn = ldb_dn_new(msg, ldb, "@INDEXLIST");
	if (!msg_idx->dn) {
		ldb_oom(ldb);
		goto op_error;
	}

	ret = ldb_msg_add_string(msg_idx, "@IDXONE", "1");
	if (ret != LDB_SUCCESS) {
		goto op_error;
	}

	for (attr = schema->attributes; attr; attr = attr->next) {
		const char *syntax = attr->syntax->ldb_syntax;
		
		if (!syntax) {
			syntax = attr->syntax->ldap_oid;
		}

		/* Write out a rough approximation of the schema as an @ATTRIBUTES value, for bootstrapping */
		if (strcmp(syntax, LDB_SYNTAX_INTEGER) == 0) {
			ret = ldb_msg_add_string(msg, attr->lDAPDisplayName, "INTEGER");
		} else if (strcmp(syntax, LDB_SYNTAX_DIRECTORY_STRING) == 0) {
			ret = ldb_msg_add_string(msg, attr->lDAPDisplayName, "CASE_INSENSITIVE");
		} 
		if (ret != LDB_SUCCESS) {
			break;
		}

		if (attr->searchFlags & SEARCH_FLAG_ATTINDEX) {
			ret = ldb_msg_add_string(msg_idx, "@IDXATTR", attr->lDAPDisplayName);
			if (ret != LDB_SUCCESS) {
				break;
			}
		}
	}

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

	/* Try to avoid churning the attributes too much - we only want to do this if they have changed */
	ret = ldb_search(ldb, mem_ctx, &res, msg->dn, LDB_SCOPE_BASE, NULL, "dn=%s", ldb_dn_get_linearized(msg->dn));
	if (ret == LDB_ERR_NO_SUCH_OBJECT) {
		ret = ldb_add(ldb, msg);
	} else if (ret != LDB_SUCCESS) {
	} else if (res->count != 1) {
		ret = ldb_add(ldb, msg);
	} else {
		ret = LDB_SUCCESS;
		/* Annoyingly added to our search results */
		ldb_msg_remove_attr(res->msgs[0], "distinguishedName");
		
		mod_msg = ldb_msg_diff(ldb, res->msgs[0], msg);
		if (mod_msg->num_elements > 0) {
			ret = dsdb_replace(ldb, mod_msg, 0);
		}
	}

	if (ret == LDB_ERR_OPERATIONS_ERROR || ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS || ret == LDB_ERR_INVALID_DN_SYNTAX) {
		/* We might be on a read-only DB or LDAP */
		ret = LDB_SUCCESS;
	}
	if (ret != LDB_SUCCESS) {
		talloc_free(mem_ctx);
		return ret;
	}

	/* Now write out the indexs, as found in the schema (if they have changed) */

	ret = ldb_search(ldb, mem_ctx, &res_idx, msg_idx->dn, LDB_SCOPE_BASE, NULL, "dn=%s", ldb_dn_get_linearized(msg_idx->dn));
	if (ret == LDB_ERR_NO_SUCH_OBJECT) {
		ret = ldb_add(ldb, msg_idx);
	} else if (ret != LDB_SUCCESS) {
	} else if (res_idx->count != 1) {
		ret = ldb_add(ldb, msg_idx);
	} else {
		ret = LDB_SUCCESS;
		/* Annoyingly added to our search results */
		ldb_msg_remove_attr(res_idx->msgs[0], "distinguishedName");

		mod_msg = ldb_msg_diff(ldb, res_idx->msgs[0], msg_idx);
		if (mod_msg->num_elements > 0) {
			ret = dsdb_replace(ldb, mod_msg, 0);
		}
	}
	if (ret == LDB_ERR_OPERATIONS_ERROR || ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS || ret == LDB_ERR_INVALID_DN_SYNTAX) {
		/* We might be on a read-only DB */
		ret = LDB_SUCCESS;
	}
	talloc_free(mem_ctx);
	return ret;

op_error:
	talloc_free(mem_ctx);
	return LDB_ERR_OPERATIONS_ERROR;
}

static int uint32_cmp(uint32_t c1, uint32_t c2)
{
	if (c1 == c2) return 0;
	return c1 > c2 ? 1 : -1;
}

static int dsdb_compare_class_by_lDAPDisplayName(struct dsdb_class **c1, struct dsdb_class **c2)
{
	return strcasecmp((*c1)->lDAPDisplayName, (*c2)->lDAPDisplayName);
}
static int dsdb_compare_class_by_governsID_id(struct dsdb_class **c1, struct dsdb_class **c2)
{
	return uint32_cmp((*c1)->governsID_id, (*c2)->governsID_id);
}
static int dsdb_compare_class_by_governsID_oid(struct dsdb_class **c1, struct dsdb_class **c2)
{
	return strcasecmp((*c1)->governsID_oid, (*c2)->governsID_oid);
}
static int dsdb_compare_class_by_cn(struct dsdb_class **c1, struct dsdb_class **c2)
{
	return strcasecmp((*c1)->cn, (*c2)->cn);
}

static int dsdb_compare_attribute_by_lDAPDisplayName(struct dsdb_attribute **a1, struct dsdb_attribute **a2)
{
	return strcasecmp((*a1)->lDAPDisplayName, (*a2)->lDAPDisplayName);
}
static int dsdb_compare_attribute_by_attributeID_id(struct dsdb_attribute **a1, struct dsdb_attribute **a2)
{
	return uint32_cmp((*a1)->attributeID_id, (*a2)->attributeID_id);
}
static int dsdb_compare_attribute_by_attributeID_oid(struct dsdb_attribute **a1, struct dsdb_attribute **a2)
{
	return strcasecmp((*a1)->attributeID_oid, (*a2)->attributeID_oid);
}
static int dsdb_compare_attribute_by_linkID(struct dsdb_attribute **a1, struct dsdb_attribute **a2)
{
	return uint32_cmp((*a1)->linkID, (*a2)->linkID);
}

/*
  create the sorted accessor arrays for the schema
 */
static int dsdb_setup_sorted_accessors(struct ldb_context *ldb,
				       struct dsdb_schema *schema)
{
	struct dsdb_class *cur;
	struct dsdb_attribute *a;
	unsigned int i;

	talloc_free(schema->classes_by_lDAPDisplayName);
	talloc_free(schema->classes_by_governsID_id);
	talloc_free(schema->classes_by_governsID_oid);
	talloc_free(schema->classes_by_cn);

	/* count the classes */
	for (i=0, cur=schema->classes; cur; i++, cur=cur->next) /* noop */ ;
	schema->num_classes = i;

	/* setup classes_by_* */
	schema->classes_by_lDAPDisplayName = talloc_array(schema, struct dsdb_class *, i);
	schema->classes_by_governsID_id    = talloc_array(schema, struct dsdb_class *, i);
	schema->classes_by_governsID_oid   = talloc_array(schema, struct dsdb_class *, i);
	schema->classes_by_cn              = talloc_array(schema, struct dsdb_class *, i);
	if (schema->classes_by_lDAPDisplayName == NULL ||
	    schema->classes_by_governsID_id == NULL ||
	    schema->classes_by_governsID_oid == NULL ||
	    schema->classes_by_cn == NULL) {
		goto failed;
	}

	for (i=0, cur=schema->classes; cur; i++, cur=cur->next) {
		schema->classes_by_lDAPDisplayName[i] = cur;
		schema->classes_by_governsID_id[i]    = cur;
		schema->classes_by_governsID_oid[i]   = cur;
		schema->classes_by_cn[i]              = cur;
	}

	/* sort the arrays */
	TYPESAFE_QSORT(schema->classes_by_lDAPDisplayName, schema->num_classes, dsdb_compare_class_by_lDAPDisplayName);
	TYPESAFE_QSORT(schema->classes_by_governsID_id, schema->num_classes, dsdb_compare_class_by_governsID_id);
	TYPESAFE_QSORT(schema->classes_by_governsID_oid, schema->num_classes, dsdb_compare_class_by_governsID_oid);
	TYPESAFE_QSORT(schema->classes_by_cn, schema->num_classes, dsdb_compare_class_by_cn);

	/* now build the attribute accessor arrays */
	talloc_free(schema->attributes_by_lDAPDisplayName);
	talloc_free(schema->attributes_by_attributeID_id);
	talloc_free(schema->attributes_by_attributeID_oid);
	talloc_free(schema->attributes_by_linkID);

	/* count the attributes */
	for (i=0, a=schema->attributes; a; i++, a=a->next) /* noop */ ;
	schema->num_attributes = i;

	/* setup attributes_by_* */
	schema->attributes_by_lDAPDisplayName = talloc_array(schema, struct dsdb_attribute *, i);
	schema->attributes_by_attributeID_id    = talloc_array(schema, struct dsdb_attribute *, i);
	schema->attributes_by_attributeID_oid   = talloc_array(schema, struct dsdb_attribute *, i);
	schema->attributes_by_linkID              = talloc_array(schema, struct dsdb_attribute *, i);
	if (schema->attributes_by_lDAPDisplayName == NULL ||
	    schema->attributes_by_attributeID_id == NULL ||
	    schema->attributes_by_attributeID_oid == NULL ||
	    schema->attributes_by_linkID == NULL) {
		goto failed;
	}

	for (i=0, a=schema->attributes; a; i++, a=a->next) {
		schema->attributes_by_lDAPDisplayName[i] = a;
		schema->attributes_by_attributeID_id[i]    = a;
		schema->attributes_by_attributeID_oid[i]   = a;
		schema->attributes_by_linkID[i]          = a;
	}

	/* sort the arrays */
	TYPESAFE_QSORT(schema->attributes_by_lDAPDisplayName, schema->num_attributes, dsdb_compare_attribute_by_lDAPDisplayName);
	TYPESAFE_QSORT(schema->attributes_by_attributeID_id, schema->num_attributes, dsdb_compare_attribute_by_attributeID_id);
	TYPESAFE_QSORT(schema->attributes_by_attributeID_oid, schema->num_attributes, dsdb_compare_attribute_by_attributeID_oid);
	TYPESAFE_QSORT(schema->attributes_by_linkID, schema->num_attributes, dsdb_compare_attribute_by_linkID);

	return LDB_SUCCESS;

failed:
	schema->classes_by_lDAPDisplayName = NULL;
	schema->classes_by_governsID_id = NULL;
	schema->classes_by_governsID_oid = NULL;
	schema->classes_by_cn = NULL;
	schema->attributes_by_lDAPDisplayName = NULL;
	schema->attributes_by_attributeID_id = NULL;
	schema->attributes_by_attributeID_oid = NULL;
	schema->attributes_by_linkID = NULL;
	ldb_oom(ldb);
	return LDB_ERR_OPERATIONS_ERROR;
}

int dsdb_setup_schema_inversion(struct ldb_context *ldb, struct dsdb_schema *schema)
{
	/* Walk the list of schema classes */

	/*  For each subClassOf, add us to subclasses of the parent */

	/* collect these subclasses into a recursive list of total subclasses, preserving order */

	/* For each subclass under 'top', write the index from it's
	 * order as an integer in the dsdb_class (for sorting
	 * objectClass lists efficiently) */

	/* Walk the list of scheam classes */
	
	/*  Create a 'total possible superiors' on each class */
	return LDB_SUCCESS;
}

/**
 * Attach the schema to an opaque pointer on the ldb, so ldb modules
 * can find it 
 */

int dsdb_set_schema(struct ldb_context *ldb, struct dsdb_schema *schema)
{
	int ret;

	ret = dsdb_setup_sorted_accessors(ldb, schema);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	ret = schema_fill_constructed(schema);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	ret = ldb_set_opaque(ldb, "dsdb_schema", schema);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	ret = ldb_set_opaque(ldb, "dsdb_use_global_schema", NULL);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	/* Set the new attributes based on the new schema */
	ret = dsdb_schema_set_attributes(ldb, schema, true);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	talloc_steal(ldb, schema);

	return LDB_SUCCESS;
}

/**
 * Global variable to hold one copy of the schema, used to avoid memory bloat
 */
static struct dsdb_schema *global_schema;

/**
 * Make this ldb use a specified schema, already fully calculated and belonging to another ldb
 */
int dsdb_reference_schema(struct ldb_context *ldb, struct dsdb_schema *schema,
			  bool write_attributes)
{
	int ret;
	ret = ldb_set_opaque(ldb, "dsdb_schema", schema);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	return LDB_SUCCESS;
}

/**
 * Make this ldb use the 'global' schema, setup to avoid having multiple copies in this process
 */
int dsdb_set_global_schema(struct ldb_context *ldb)
{
	int ret;
	void *use_global_schema = (void *)1;
	if (!global_schema) {
		return LDB_SUCCESS;
	}

	ret = ldb_set_opaque(ldb, "dsdb_use_global_schema", use_global_schema);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	/* Set the new attributes based on the new schema */
	ret = dsdb_schema_set_attributes(ldb, global_schema, false /* Don't write attributes, it's expensive */);
	if (ret == LDB_SUCCESS) {
		/* Keep a reference to this schema, just incase the original copy is replaced */
		if (talloc_reference(ldb, global_schema) == NULL) {
			return LDB_ERR_OPERATIONS_ERROR;
		}
	}

	return ret;
}

/**
 * Find the schema object for this ldb
 *
 * If reference_ctx is not NULL, then talloc_reference onto that context
 */

struct dsdb_schema *dsdb_get_schema(struct ldb_context *ldb, TALLOC_CTX *reference_ctx)
{
	const void *p;
	struct dsdb_schema *schema_out;
	struct dsdb_schema *schema_in;
	bool use_global_schema;

	/* see if we have a cached copy */
	use_global_schema = (ldb_get_opaque(ldb, "dsdb_use_global_schema") != NULL);
	if (use_global_schema) {
		schema_in = global_schema;
	} else {
		p = ldb_get_opaque(ldb, "dsdb_schema");

		schema_in = talloc_get_type(p, struct dsdb_schema);
		if (!schema_in) {
			return NULL;
		}
	}

	if (schema_in->refresh_fn && !schema_in->refresh_in_progress) {
		schema_in->refresh_in_progress = true;
		/* This may change schema, if it needs to reload it from disk */
		schema_out = schema_in->refresh_fn(schema_in->loaded_from_module,
						   schema_in,
						   use_global_schema);
		schema_in->refresh_in_progress = false;
		if (schema_out != schema_in) {
			talloc_unlink(schema_in, ldb);
		}
	} else {
		schema_out = schema_in;
	}

	if (!reference_ctx) {
		return schema_out;
	} else {
		return talloc_reference(reference_ctx, schema_out);
	}
}

/**
 * Make the schema found on this ldb the 'global' schema
 */

void dsdb_make_schema_global(struct ldb_context *ldb, struct dsdb_schema *schema)
{
	if (!schema) {
		return;
	}

	if (global_schema) {
		talloc_unlink(talloc_autofree_context(), global_schema);
	}

	/* Wipe any reference to the exact schema - we will set 'use the global schema' below */
	ldb_set_opaque(ldb, "dsdb_schema", NULL);

	/* we want the schema to be around permanently */
	talloc_reparent(ldb, talloc_autofree_context(), schema);
	global_schema = schema;

	/* This calls the talloc_reference() of the global schema back onto the ldb */
	dsdb_set_global_schema(ldb);
}

/* When loading the schema from LDIF files, we don't get the extended DNs. 
   
   We need to set these up, so that from the moment we start the provision, the defaultObjectCategory links are set up correctly. 
 */
int dsdb_schema_fill_extended_dn(struct ldb_context *ldb, struct dsdb_schema *schema)
{
	struct dsdb_class *cur;
	const struct dsdb_class *target_class;
	for (cur = schema->classes; cur; cur = cur->next) {
		const struct ldb_val *rdn;
		struct ldb_val guid;
		NTSTATUS status;
		struct ldb_dn *dn = ldb_dn_new(NULL, ldb, cur->defaultObjectCategory);

		if (!dn) {
			return LDB_ERR_INVALID_DN_SYNTAX;
		}
		rdn = ldb_dn_get_component_val(dn, 0);
		if (!rdn) {
			talloc_free(dn);
			return LDB_ERR_INVALID_DN_SYNTAX;
		}
		target_class = dsdb_class_by_cn_ldb_val(schema, rdn);
		if (!target_class) {
			talloc_free(dn);
			return LDB_ERR_CONSTRAINT_VIOLATION;
		}
		
		status = GUID_to_ndr_blob(&target_class->objectGUID, dn, &guid);
		if (!NT_STATUS_IS_OK(status)) {
			talloc_free(dn);
			return LDB_ERR_OPERATIONS_ERROR;
		}
		ldb_dn_set_extended_component(dn, "GUID", &guid);

		cur->defaultObjectCategory = ldb_dn_get_extended_linearized(cur, dn, 1);
		talloc_free(dn);
	}
	return LDB_SUCCESS;
}

/** 
 * Add an element to the schema (attribute or class) from an LDB message
 */
WERROR dsdb_schema_set_el_from_ldb_msg(struct ldb_context *ldb, struct dsdb_schema *schema, 
				       struct ldb_message *msg) 
{
	static struct ldb_parse_tree *attr_tree, *class_tree;
	if (!attr_tree) {
		attr_tree = ldb_parse_tree(talloc_autofree_context(), "(objectClass=attributeSchema)");
		if (!attr_tree) {
			return WERR_NOMEM;
		}
	}

	if (!class_tree) {
		class_tree = ldb_parse_tree(talloc_autofree_context(), "(objectClass=classSchema)");
		if (!class_tree) {
			return WERR_NOMEM;
		}
	}

	if (ldb_match_msg(ldb, msg, attr_tree, NULL, LDB_SCOPE_BASE)) {
		return dsdb_attribute_from_ldb(ldb, schema, msg);
	} else if (ldb_match_msg(ldb, msg, class_tree, NULL, LDB_SCOPE_BASE)) {
		return dsdb_class_from_ldb(schema, msg);
	}

	/* Don't fail on things not classes or attributes */
	return WERR_OK;
}

/**
 * Rather than read a schema from the LDB itself, read it from an ldif
 * file.  This allows schema to be loaded and used while adding the
 * schema itself to the directory.
 */

WERROR dsdb_set_schema_from_ldif(struct ldb_context *ldb, const char *pf, const char *df)
{
	struct ldb_ldif *ldif;
	struct ldb_message *msg;
	TALLOC_CTX *mem_ctx;
	WERROR status;
	int ret;
	struct dsdb_schema *schema;
	const struct ldb_val *prefix_val;
	const struct ldb_val *info_val;
	struct ldb_val info_val_default;


	mem_ctx = talloc_new(ldb);
	if (!mem_ctx) {
		goto nomem;
	}

	schema = dsdb_new_schema(mem_ctx, lp_iconv_convenience(ldb_get_opaque(ldb, "loadparm")));

	schema->fsmo.we_are_master = true;
	schema->fsmo.master_dn = ldb_dn_new_fmt(schema, ldb, "@PROVISION_SCHEMA_MASTER");
	if (!schema->fsmo.master_dn) {
		goto nomem;
	}

	/*
	 * load the prefixMap attribute from pf
	 */
	ldif = ldb_ldif_read_string(ldb, &pf);
	if (!ldif) {
		status = WERR_INVALID_PARAM;
		goto failed;
	}
	talloc_steal(mem_ctx, ldif);

	msg = ldb_msg_canonicalize(ldb, ldif->msg);
	if (!msg) {
		goto nomem;
	}
	talloc_steal(mem_ctx, msg);
	talloc_free(ldif);

	prefix_val = ldb_msg_find_ldb_val(msg, "prefixMap");
	if (!prefix_val) {
	    	status = WERR_INVALID_PARAM;
		goto failed;
	}

	info_val = ldb_msg_find_ldb_val(msg, "schemaInfo");
	if (!info_val) {
		info_val_default = strhex_to_data_blob(mem_ctx, "FF0000000000000000000000000000000000000000");
		if (!info_val_default.data) {
			goto nomem;
		}
		info_val = &info_val_default;
	}

	status = dsdb_load_oid_mappings_ldb(schema, prefix_val, info_val);
	if (!W_ERROR_IS_OK(status)) {
		goto failed;
	}

	/*
	 * load the attribute and class definitions outof df
	 */
	while ((ldif = ldb_ldif_read_string(ldb, &df))) {
		talloc_steal(mem_ctx, ldif);

		msg = ldb_msg_canonicalize(ldb, ldif->msg);
		if (!msg) {
			goto nomem;
		}

		status = dsdb_schema_set_el_from_ldb_msg(ldb, schema, msg);
		talloc_free(ldif);
		if (!W_ERROR_IS_OK(status)) {
			goto failed;
		}
	}

	ret = dsdb_set_schema(ldb, schema);
	if (ret != LDB_SUCCESS) {
		status = WERR_FOOBAR;
		goto failed;
	}

	ret = dsdb_schema_fill_extended_dn(ldb, schema);
	if (ret != LDB_SUCCESS) {
		status = WERR_FOOBAR;
		goto failed;
	}

	goto done;

nomem:
	status = WERR_NOMEM;
failed:
done:
	talloc_free(mem_ctx);
	return status;
}