/* 
   ldb database library

   Copyright (C) Andrew Tridgell  2004

     ** NOTE! The following LGPL license applies to the ldb
     ** library. This does NOT imply that all of Samba is released
     ** under the LGPL
   
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

/*
 *  Name: ldb
 *
 *  Component: ldb search functions
 *
 *  Description: functions to search ldb+tdb databases
 *
 *  Author: Andrew Tridgell
 */

#include "includes.h"
#include "ldb/include/ldb.h"
#include "ldb/include/ldb_private.h"
#include "ldb/ldb_tdb/ldb_tdb.h"

/*
  add one element to a message
*/
static int msg_add_element(struct ldb_context *ldb, 
			   struct ldb_message *ret, const struct ldb_message_element *el)
{
	unsigned int i;
	struct ldb_message_element *e2, *elnew;

	e2 = talloc_realloc(ret, ret->elements, struct ldb_message_element, ret->num_elements+1);
	if (!e2) {
		return -1;
	}
	ret->elements = e2;
	
	elnew = &e2[ret->num_elements];

	elnew->name = talloc_strdup(ret->elements, el->name);
	if (!elnew->name) {
		return -1;
	}

	if (el->num_values) {
		elnew->values = talloc_array(ret->elements, struct ldb_val, el->num_values);
		if (!elnew->values) {
			return -1;
		}
	} else {
		elnew->values = NULL;
	}

	for (i=0;i<el->num_values;i++) {
		elnew->values[i] = ldb_val_dup(elnew->values, &el->values[i]);
		if (elnew->values[i].length != el->values[i].length) {
			return -1;
		}
	}

	elnew->num_values = el->num_values;

	ret->num_elements++;

	return 0;
}

/*
  add all elements from one message into another
 */
static int msg_add_all_elements(struct ldb_module *module, struct ldb_message *ret,
				const struct ldb_message *msg)
{
	struct ldb_context *ldb = module->ldb;
	unsigned int i;

	for (i=0;i<msg->num_elements;i++) {
		const struct ldb_attrib_handler *h;
		h = ldb_attrib_handler(ldb, msg->elements[i].name);
		if ((msg->dn[0] != '@') && (h->flags & LDB_ATTR_FLAG_HIDDEN)) {
			continue;
		}
		if (msg_add_element(ldb, ret, &msg->elements[i]) != 0) {
			return -1;
		}
	}

	return 0;
}


/*
  pull the specified list of attributes from a message
 */
static struct ldb_message *ltdb_pull_attrs(struct ldb_module *module, 
					   const struct ldb_message *msg, 
					   const char * const *attrs)
{
	struct ldb_context *ldb = module->ldb;
	struct ldb_message *ret;
	int i;

	ret = talloc(ldb, struct ldb_message);
	if (!ret) {
		return NULL;
	}

	ret->dn = talloc_strdup(ret, msg->dn);
	if (!ret->dn) {
		talloc_free(ret);
		return NULL;
	}

	ret->num_elements = 0;
	ret->elements = NULL;

	if (!attrs) {
		if (msg_add_all_elements(module, ret, msg) != 0) {
			talloc_free(ret);
			return NULL;
		}
		return ret;
	}

	for (i=0;attrs[i];i++) {
		struct ldb_message_element *el;

		if (strcmp(attrs[i], "*") == 0) {
			if (msg_add_all_elements(module, ret, msg) != 0) {
				talloc_free(ret);
				return NULL;
			}
			continue;
		}

		if (ldb_attr_cmp(attrs[i], "dn") == 0 ||
		    ldb_attr_cmp(attrs[i], "distinguishedName") == 0) {
			struct ldb_message_element el2;
			struct ldb_val val;

			el2.flags = 0;
			el2.name = talloc_strdup(ret, attrs[i]);
			if (!el2.name) {
				talloc_free(ret);
				return NULL;				
			}
			el2.num_values = 1;
			el2.values = &val;
			val.data = ret->dn;
			val.length = strlen(ret->dn);

			if (msg_add_element(ldb, ret, &el2) != 0) {
				talloc_free(ret);
				return NULL;				
			}
			talloc_free(discard_const_p(char, el2.name));
			continue;
		}

		el = ldb_msg_find_element(msg, attrs[i]);
		if (!el) {
			continue;
		}
		if (msg_add_element(ldb, ret, el) != 0) {
			talloc_free(ret);
			return NULL;				
		}
	}

	return ret;
}


/*
  search the database for a single simple dn, returning all attributes
  in a single message

  return 1 on success, 0 on record-not-found and -1 on error
*/
int ltdb_search_dn1(struct ldb_module *module, const char *dn, struct ldb_message *msg)
{
	struct ltdb_private *ltdb = module->private_data;
	int ret;
	TDB_DATA tdb_key, tdb_data, tdb_data2;

	memset(msg, 0, sizeof(*msg));

	/* form the key */
	tdb_key = ltdb_key(module, dn);
	if (!tdb_key.dptr) {
		return -1;
	}

	tdb_data = tdb_fetch(ltdb->tdb, tdb_key);
	talloc_free(tdb_key.dptr);
	if (!tdb_data.dptr) {
		return 0;
	}

	tdb_data2.dptr = talloc_memdup(msg, tdb_data.dptr, tdb_data.dsize);
	free(tdb_data.dptr);
	if (!tdb_data2.dptr) {
		return -1;
	}
	tdb_data2.dsize = tdb_data.dsize;

	msg->num_elements = 0;
	msg->elements = NULL;

	ret = ltdb_unpack_data(module, &tdb_data2, msg);
	if (ret == -1) {
		talloc_free(tdb_data2.dptr);
		return -1;		
	}

	if (!msg->dn) {
		msg->dn = talloc_strdup(tdb_data2.dptr, dn);
	}
	if (!msg->dn) {
		talloc_free(tdb_data2.dptr);
		return -1;
	}

	return 1;
}


/*
  search the database for a single simple dn
*/
static int ltdb_search_dn(struct ldb_module *module, const char *dn,
			  const char * const attrs[], struct ldb_message ***res)
{
	struct ldb_context *ldb = module->ldb;
	struct ltdb_private *ltdb = module->private_data;
	int ret;
	struct ldb_message *msg, *msg2;

	*res = NULL;

	if (ltdb_lock_read(module) != 0) {
		return -1;
	}

	ltdb->last_err_string = NULL;

	if (ltdb_cache_load(module) != 0) {
		ltdb_unlock_read(module);
		return -1;
	}

	*res = talloc_array(ldb, struct ldb_message *, 2);
	if (! *res) {
		goto failed;
	}

	msg = talloc(*res, struct ldb_message);
	if (msg == NULL) {
		goto failed;
	}

	ret = ltdb_search_dn1(module, dn, msg);
	if (ret != 1) {
		talloc_free(*res);
		*res = NULL;
		ltdb_unlock_read(module);
		return 0;
	}

	msg2 = ltdb_pull_attrs(module, msg, attrs);

	talloc_free(msg);
	if (!msg2) {
		goto failed;
	}

	(*res)[0] = talloc_steal(*res, msg2);
	(*res)[1] = NULL;

	ltdb_unlock_read(module);

	return 1;

failed:
	talloc_free(*res);
	ltdb_unlock_read(module);
	return -1;
}


/*
  add a set of attributes from a record to a set of results
  return 0 on success, -1 on failure
*/
int ltdb_add_attr_results(struct ldb_module *module, struct ldb_message *msg,
			  const char * const attrs[], 
			  int *count, 
			  struct ldb_message ***res)
{
	struct ldb_context *ldb = module->ldb;
	struct ldb_message *msg2;
	struct ldb_message **res2;

	/* pull the attributes that the user wants */
	msg2 = ltdb_pull_attrs(module, msg, attrs);
	if (!msg2) {
		return -1;
	}

	/* add to the results list */
	res2 = talloc_realloc(ldb, *res, struct ldb_message *, (*count)+2);
	if (!res2) {
		talloc_free(msg2);
		return -1;
	}

	(*res) = res2;

	(*res)[*count] = talloc_steal(*res, msg2);
	(*res)[(*count)+1] = NULL;
	(*count)++;

	return 0;
}


/*
  internal search state during a full db search
*/
struct ltdb_search_info {
	struct ldb_module *module;
	struct ldb_parse_tree *tree;
	const char *base;
	enum ldb_scope scope;
	const char * const *attrs;
	struct ldb_message **msgs;
	int failures;
	int count;
};


/*
  search function for a non-indexed search
 */
static int search_func(struct tdb_context *tdb, TDB_DATA key, TDB_DATA data, void *state)
{
	struct ltdb_search_info *sinfo = state;
	struct ldb_message *msg;
	int ret;

	if (key.dsize < 4 || 
	    strncmp(key.dptr, "DN=", 3) != 0) {
		return 0;
	}

	msg = talloc(sinfo, struct ldb_message);
	if (msg == NULL) {
		return -1;
	}

	/* unpack the record */
	ret = ltdb_unpack_data(sinfo->module, &data, msg);
	if (ret == -1) {
		sinfo->failures++;
		talloc_free(msg);
		return 0;
	}

	if (!msg->dn) {
		msg->dn = key.dptr + 3;
	}

	/* see if it matches the given expression */
	if (!ldb_match_msg(sinfo->module->ldb, msg, sinfo->tree, 
			       sinfo->base, sinfo->scope)) {
		talloc_free(msg);
		return 0;
	}

	ret = ltdb_add_attr_results(sinfo->module, msg, sinfo->attrs, &sinfo->count, &sinfo->msgs);

	if (ret == -1) {
		sinfo->failures++;
	}

	talloc_free(msg);

	return ret;
}


/*
  search the database with a LDAP-like expression.
  this is the "full search" non-indexed variant
*/
static int ltdb_search_full(struct ldb_module *module, 
			    const char *base,
			    enum ldb_scope scope,
			    struct ldb_parse_tree *tree,
			    const char * const attrs[], struct ldb_message ***res)
{
	struct ltdb_private *ltdb = module->private_data;
	int ret, count;
	struct ltdb_search_info *sinfo;

	sinfo = talloc(ltdb, struct ltdb_search_info);
	if (sinfo == NULL) {
		return -1;
	}

	sinfo->tree = tree;
	sinfo->module = module;
	sinfo->scope = scope;
	sinfo->base = base;
	sinfo->attrs = attrs;
	sinfo->msgs = NULL;
	sinfo->count = 0;
	sinfo->failures = 0;

	ret = tdb_traverse(ltdb->tdb, search_func, sinfo);

	if (ret == -1) {
		talloc_free(sinfo);
		return -1;
	}

	*res = talloc_steal(ltdb, sinfo->msgs);
	count = sinfo->count;

	talloc_free(sinfo);

	return count;
}


/*
  search the database with a LDAP-like expression.
  choses a search method
*/
int ltdb_search_bytree(struct ldb_module *module, const char *base,
		       enum ldb_scope scope, struct ldb_parse_tree *tree,
		       const char * const attrs[], struct ldb_message ***res)
{
	struct ltdb_private *ltdb = module->private_data;
	int ret;

	/* it is important that we handle dn queries this way, and not
	   via a full db search, otherwise ldb is horribly slow */
	if (tree->operation == LDB_OP_EQUALITY &&
	    (ldb_attr_cmp(tree->u.equality.attr, "dn") == 0 ||
	     ldb_attr_cmp(tree->u.equality.attr, "distinguishedName") == 0)) {
		return ltdb_search_dn(module, tree->u.equality.value.data, attrs, res);
	}

	if (ltdb_lock_read(module) != 0) {
		return -1;
	}

	ltdb->last_err_string = NULL;

	if (ltdb_cache_load(module) != 0) {
		ltdb_unlock_read(module);
		return -1;
	}

	*res = NULL;

	ret = ltdb_search_indexed(module, base, scope, tree, attrs, res);
	if (ret == -1) {
		ret = ltdb_search_full(module, base, scope, tree, attrs, res);
	}

	ltdb_unlock_read(module);

	return ret;
}


/*
  search the database with a LDAP-like expression.
  choses a search method
*/
int ltdb_search(struct ldb_module *module, const char *base,
		enum ldb_scope scope, const char *expression,
		const char * const attrs[], struct ldb_message ***res)
{
	struct ltdb_private *ltdb = module->private_data;
	struct ldb_parse_tree *tree;
	int ret;

	/* check if we are looking for a simple dn */
	if (scope == LDB_SCOPE_BASE && (expression == NULL || expression[0] == '\0')) {
		ret = ltdb_search_dn(module, base, attrs, res);
		return ret;
	}

	tree = ldb_parse_tree(ltdb, expression);
	if (tree == NULL) {
		ltdb->last_err_string = "expression parse failed";
		return -1;
	}

	ret = ltdb_search_bytree(module, base, scope, tree, attrs, res);
	talloc_free(tree);
	return ret;
}