ldb_map.c

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/*
   ldb database mapping module

   Copyright (C) Jelmer Vernooij 2005
   Copyright (C) Martin Kuehl <[e-mail]> 2006

     ** 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 3 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, see <http://www.gnu.org/licenses/>.

*/

/* 
 *  Name: ldb
 *
 *  Component: ldb ldb_map module
 *
 *  Description: Map portions of data into a different format on a
 *  remote partition.
 *
 *  Author: Jelmer Vernooij, Martin Kuehl
 */

#include "ldb_includes.h"

#include "ldb_map.h"
#include "ldb_map_private.h"

#ifndef _PUBLIC_
#define _PUBLIC_
#endif

/* Description of the provided ldb requests:
 - special attribute 'isMapped'

 - search:
     - if parse tree can be split
         - search remote records w/ remote attrs and parse tree
     - otherwise
         - enumerate all remote records
     - for each remote result
         - map remote result to local message
         - search local result
         - is present
             - merge local into remote result
             - run callback on merged result
         - otherwise
             - run callback on remote result

 - add:
     - split message into local and remote part
     - if local message is not empty
         - add isMapped to local message
         - add local message
     - add remote message

 - modify:
     - split message into local and remote part
     - if local message is not empty
         - add isMapped to local message
         - search for local record
         - if present
             - modify local record
         - otherwise
             - add local message
     - modify remote record

 - delete:
     - search for local record
     - if present
         - delete local record
     - delete remote record

 - rename:
     - search for local record
     - if present
         - rename local record
         - modify local isMapped
     - rename remote record
*/



/* Private data structures
 * ======================= */

/* Global private data */
/* Extract mappings from private data. */
const struct ldb_map_context *map_get_context(struct ldb_module *module)
{
	const struct map_private *data = talloc_get_type(module->private_data, struct map_private);
	return data->context;
}

/* Create a generic request context. */
static struct map_context *map_init_context(struct ldb_handle *h, struct ldb_request *req)
{
	struct map_context *ac;

	ac = talloc_zero(h, struct map_context);
	if (ac == NULL) {
		map_oom(h->module);
		return NULL;
	}

	ac->module = h->module;
	ac->orig_req = req;

	return ac;
}

/* Create a search request context. */
struct map_search_context *map_init_search_context(struct map_context *ac, struct ldb_reply *ares)
{
	struct map_search_context *sc;

	sc = talloc_zero(ac, struct map_search_context);
	if (sc == NULL) {
		map_oom(ac->module);
		return NULL;
	}

	sc->ac = ac;
	sc->local_res = NULL;
	sc->remote_res = ares;

	return sc;
}

/* Create a request context and handle. */
struct ldb_handle *map_init_handle(struct ldb_request *req, struct ldb_module *module)
{
	struct map_context *ac;
	struct ldb_handle *h;

	h = talloc_zero(req, struct ldb_handle);
	if (h == NULL) {
		map_oom(module);
		return NULL;
	}

	h->module = module;

	ac = map_init_context(h, req);
	if (ac == NULL) {
		talloc_free(h);
		return NULL;
	}

	h->private_data = (void *)ac;

	h->state = LDB_ASYNC_INIT;
	h->status = LDB_SUCCESS;

	return h;
}


/* Dealing with DNs for different partitions
 * ========================================= */

/* Check whether any data should be stored in the local partition. */
bool map_check_local_db(struct ldb_module *module)
{
	const struct ldb_map_context *data = map_get_context(module);

	if (!data->remote_base_dn || !data->local_base_dn) {
		return false;
	}

	return true;
}

/* Copy a DN with the base DN of the local partition. */
static struct ldb_dn *ldb_dn_rebase_local(void *mem_ctx, const struct ldb_map_context *data, struct ldb_dn *dn)
{
	struct ldb_dn *new_dn;

	new_dn = ldb_dn_copy(mem_ctx, dn);
	if ( ! ldb_dn_validate(new_dn)) {
		talloc_free(new_dn);
		return NULL;
	}

	/* may be we don't need to rebase at all */
	if ( ! data->remote_base_dn || ! data->local_base_dn) {
		return new_dn;
	}

	if ( ! ldb_dn_remove_base_components(new_dn, ldb_dn_get_comp_num(data->remote_base_dn))) {
		talloc_free(new_dn);
		return NULL;
	}

	if ( ! ldb_dn_add_base(new_dn, data->local_base_dn)) {
		talloc_free(new_dn);
		return NULL;
	}

	return new_dn;
}

/* Copy a DN with the base DN of the remote partition. */
static struct ldb_dn *ldb_dn_rebase_remote(void *mem_ctx, const struct ldb_map_context *data, struct ldb_dn *dn)
{
	struct ldb_dn *new_dn;

	new_dn = ldb_dn_copy(mem_ctx, dn);
	if ( ! ldb_dn_validate(new_dn)) {
		talloc_free(new_dn);
		return NULL;
	}

	/* may be we don't need to rebase at all */
	if ( ! data->remote_base_dn || ! data->local_base_dn) {
		return new_dn;
	}

	if ( ! ldb_dn_remove_base_components(new_dn, ldb_dn_get_comp_num(data->local_base_dn))) {
		talloc_free(new_dn);
		return NULL;
	}

	if ( ! ldb_dn_add_base(new_dn, data->remote_base_dn)) {
		talloc_free(new_dn);
		return NULL;
	}

	return new_dn;
}

/* Run a request and make sure it targets the remote partition. */
/* TODO: free old DNs and messages? */
int ldb_next_remote_request(struct ldb_module *module, struct ldb_request *request)
{
	const struct ldb_map_context *data = map_get_context(module);
	struct ldb_message *msg;

	switch (request->operation) {
	case LDB_SEARCH:
		if (request->op.search.base) {
			request->op.search.base = ldb_dn_rebase_remote(request, data, request->op.search.base);
		} else {
			request->op.search.base = data->remote_base_dn;
			/* TODO: adjust scope? */
		}
		break;

	case LDB_ADD:
		msg = ldb_msg_copy_shallow(request, request->op.add.message);
		msg->dn = ldb_dn_rebase_remote(msg, data, msg->dn);
		request->op.add.message = msg;
		break;

	case LDB_MODIFY:
		msg = ldb_msg_copy_shallow(request, request->op.mod.message);
		msg->dn = ldb_dn_rebase_remote(msg, data, msg->dn);
		request->op.mod.message = msg;
		break;

	case LDB_DELETE:
		request->op.del.dn = ldb_dn_rebase_remote(request, data, request->op.del.dn);
		break;

	case LDB_RENAME:
		request->op.rename.olddn = ldb_dn_rebase_remote(request, data, request->op.rename.olddn);
		request->op.rename.newdn = ldb_dn_rebase_remote(request, data, request->op.rename.newdn);
		break;

	default:
		ldb_debug(module->ldb, LDB_DEBUG_ERROR, "ldb_map: "
			  "Invalid remote request!\n");
		return LDB_ERR_OPERATIONS_ERROR;
	}

	return ldb_next_request(module, request);
}


/* Finding mappings for attributes and objectClasses
 * ================================================= */

/* Find an objectClass mapping by the local name. */
static const struct ldb_map_objectclass *map_objectclass_find_local(const struct ldb_map_context *data, const char *name)
{
	int i;

	for (i = 0; data->objectclass_maps && data->objectclass_maps[i].local_name; i++) {
		if (ldb_attr_cmp(data->objectclass_maps[i].local_name, name) == 0) {
			return &data->objectclass_maps[i];
		}
	}

	return NULL;
}

/* Find an objectClass mapping by the remote name. */
static const struct ldb_map_objectclass *map_objectclass_find_remote(const struct ldb_map_context *data, const char *name)
{
	int i;

	for (i = 0; data->objectclass_maps && data->objectclass_maps[i].remote_name; i++) {
		if (ldb_attr_cmp(data->objectclass_maps[i].remote_name, name) == 0) {
			return &data->objectclass_maps[i];
		}
	}

	return NULL;
}

/* Find an attribute mapping by the local name. */
const struct ldb_map_attribute *map_attr_find_local(const struct ldb_map_context *data, const char *name)
{
	int i;

	for (i = 0; data->attribute_maps[i].local_name; i++) {
		if (ldb_attr_cmp(data->attribute_maps[i].local_name, name) == 0) {
			return &data->attribute_maps[i];
		}
	}
	for (i = 0; data->attribute_maps[i].local_name; i++) {
		if (ldb_attr_cmp(data->attribute_maps[i].local_name, "*") == 0) {
			return &data->attribute_maps[i];
		}
	}

	return NULL;
}

/* Find an attribute mapping by the remote name. */
const struct ldb_map_attribute *map_attr_find_remote(const struct ldb_map_context *data, const char *name)
{
	const struct ldb_map_attribute *map;
	const struct ldb_map_attribute *wildcard = NULL;
	int i, j;

	for (i = 0; data->attribute_maps[i].local_name; i++) {
		map = &data->attribute_maps[i];
		if (ldb_attr_cmp(map->local_name, "*") == 0) {
			wildcard = &data->attribute_maps[i];
		}

		switch (map->type) {
		case MAP_IGNORE:
			break;

		case MAP_KEEP:
			if (ldb_attr_cmp(map->local_name, name) == 0) {
				return map;
			}
			break;

		case MAP_RENAME:
		case MAP_CONVERT:
			if (ldb_attr_cmp(map->u.rename.remote_name, name) == 0) {
				return map;
			}
			break;

		case MAP_GENERATE:
			for (j = 0; map->u.generate.remote_names && map->u.generate.remote_names[j]; j++) {
				if (ldb_attr_cmp(map->u.generate.remote_names[j], name) == 0) {
					return map;
				}
			}
			break;
		}
	}

	/* We didn't find it, so return the wildcard record if one was configured */
	return wildcard;
}


/* Mapping attributes
 * ================== */

/* Check whether an attribute will be mapped into the remote partition. */
bool map_attr_check_remote(const struct ldb_map_context *data, const char *attr)
{
	const struct ldb_map_attribute *map = map_attr_find_local(data, attr);

	if (map == NULL) {
		return false;
	}
	if (map->type == MAP_IGNORE) {
		return false;
	}

	return true;
}

/* Map an attribute name into the remote partition. */
const char *map_attr_map_local(void *mem_ctx, const struct ldb_map_attribute *map, const char *attr)
{
	if (map == NULL) {
		return talloc_strdup(mem_ctx, attr);
	}

	switch (map->type) {
	case MAP_KEEP:
		return talloc_strdup(mem_ctx, attr);

	case MAP_RENAME:
	case MAP_CONVERT:
		return talloc_strdup(mem_ctx, map->u.rename.remote_name);

	default:
		return NULL;
	}
}

/* Map an attribute name back into the local partition. */
const char *map_attr_map_remote(void *mem_ctx, const struct ldb_map_attribute *map, const char *attr)
{
	if (map == NULL) {
		return talloc_strdup(mem_ctx, attr);
	}

	if (map->type == MAP_KEEP) {
		return talloc_strdup(mem_ctx, attr);
	}

	return talloc_strdup(mem_ctx, map->local_name);
}


/* Merge two lists of attributes into a single one. */
int map_attrs_merge(struct ldb_module *module, void *mem_ctx, 
		    const char ***attrs, const char * const *more_attrs)
{
	int i, j, k;

	for (i = 0; *attrs && (*attrs)[i]; i++) /* noop */ ;
	for (j = 0; more_attrs && more_attrs[j]; j++) /* noop */ ;
	
	*attrs = talloc_realloc(mem_ctx, *attrs, const char *, i+j+1);
	if (*attrs == NULL) {
		map_oom(module);
		return -1;
	}

	for (k = 0; k < j; k++) {
		(*attrs)[i + k] = more_attrs[k];
	}

	(*attrs)[i+k] = NULL;