source: branches/samba-3.5.x/source3/lib/ldb/modules/objectclass.c

/* 
   ldb database library

   Copyright (C) Simo Sorce  2006
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2006

     ** 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: objectClass sorting module
 *
 *  Description: sort the objectClass attribute into the class hierarchy
 *
 *  Author: Andrew Bartlett
 */

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

struct oc_context {

        enum oc_step {OC_DO_REQ, OC_SEARCH_SELF, OC_DO_MOD} step;

        struct ldb_module *module;
        struct ldb_request *orig_req;

        struct ldb_request *down_req;

        struct ldb_request *search_req;
        struct ldb_reply *search_res;

        struct ldb_request *mod_req;
};

struct class_list {
        struct class_list *prev, *next;
        const char *objectclass;
};

static struct ldb_handle *oc_init_handle(struct ldb_request *req, struct ldb_module *module)
{
        struct oc_context *ac;
        struct ldb_handle *h;

        h = talloc_zero(req, struct ldb_handle);
        if (h == NULL) {
                ldb_set_errstring(module->ldb, "Out of Memory");
                return NULL;
        }

        h->module = module;

        ac = talloc_zero(h, struct oc_context);
        if (ac == NULL) {
                ldb_set_errstring(module->ldb, "Out of Memory");
                talloc_free(h);
                return NULL;
        }

        h->private_data = (void *)ac;

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

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

        return h;
}

static int objectclass_sort(struct ldb_module *module,
                            TALLOC_CTX *mem_ctx,
                            struct ldb_message_element *objectclass_element,
                            struct class_list **sorted_out) 
{
        int i;
        int layer;
        struct class_list *sorted = NULL, *parent_class = NULL,
                *subclass = NULL, *unsorted = NULL, *current, *poss_subclass;
        /* DESIGN:
         *
         * We work on 4 different 'bins' (implemented here as linked lists):
         *
         * * sorted:       the eventual list, in the order we wish to push
         *                 into the database.  This is the only ordered list.
         *
         * * parent_class: The current parent class 'bin' we are
         *                 trying to find subclasses for
         *
         * * subclass:     The subclasses we have found so far
         *
         * * unsorted:     The remaining objectClasses
         *
         * The process is a matter of filtering objectClasses up from
         * unsorted into sorted.  Order is irrelevent in the later 3 'bins'.
         * 
         * We start with 'top' (found and promoted to parent_class
         * initially).  Then we find (in unsorted) all the direct
         * subclasses of 'top'.  parent_classes is concatenated onto
         * the end of 'sorted', and subclass becomes the list in
         * parent_class.
         *
         * We then repeat, until we find no more subclasses.  Any left
         * over classes are added to the end.
         *
         */

        /* Firstly, dump all the objectClass elements into the
         * unsorted bin, except for 'top', which is special */
        for (i=0; i < objectclass_element->num_values; i++) {
                current = talloc(mem_ctx, struct class_list);
                if (!current) {
                        ldb_set_errstring(module->ldb, "objectclass: out of memory allocating objectclass list");
                        talloc_free(mem_ctx);
                        return LDB_ERR_OPERATIONS_ERROR;
                }
                current->objectclass = (const char *)objectclass_element->values[i].data;

                /* this is the root of the tree.  We will start
                 * looking for subclasses from here */
                if (ldb_attr_cmp("top", current->objectclass) == 0) {
                        DLIST_ADD(parent_class, current);
                } else {
                        DLIST_ADD(unsorted, current);
                }
        }

        /* DEBUGGING aid:  how many layers are we down now? */
        layer = 0;
        do {
                layer++;
                /* Find all the subclasses of classes in the
                 * parent_classes.  Push them onto the subclass list */

                /* Ensure we don't bother if there are no unsorted entries left */
                for (current = parent_class; unsorted && current; current = current->next) {
                        const char **subclasses = ldb_subclass_list(module->ldb, current->objectclass);

                        /* Walk the list of possible subclasses in unsorted */
                        for (poss_subclass = unsorted; poss_subclass; ) {
                                struct class_list *next;
                                
                                /* Save the next pointer, as the DLIST_ macros will change poss_subclass->next */
                                next = poss_subclass->next;

                                for (i = 0; subclasses && subclasses[i]; i++) {
                                        if (ldb_attr_cmp(poss_subclass->objectclass, subclasses[i]) == 0) {
                                                DLIST_REMOVE(unsorted, poss_subclass);
                                                DLIST_ADD(subclass, poss_subclass);

                                                break;
                                        }
                                }
                                poss_subclass = next;
                        }
                }

                /* Now push the parent_classes as sorted, we are done with
                these.  Add to the END of the list by concatenation */
                DLIST_CONCATENATE(sorted, parent_class, struct class_list *);

                /* and now find subclasses of these */
                parent_class = subclass;
                subclass = NULL;

                /* If we didn't find any subclasses we will fall out
                 * the bottom here */
        } while (parent_class);

        /* This shouldn't happen, and would break MMC, but we can't
         * afford to loose objectClasses.  Perhaps there was no 'top',
         * or some other schema error? 
         *
         * Detecting schema errors is the job of the schema module, so
         * at this layer we just try not to loose data
         */
        DLIST_CONCATENATE(sorted, unsorted, struct class_list *);

        *sorted_out = sorted;
        return LDB_SUCCESS;
}

static int objectclass_add(struct ldb_module *module, struct ldb_request *req)
{
        struct ldb_message_element *objectclass_element;
        struct class_list *sorted, *current;
        struct ldb_request *down_req;
        struct ldb_message *msg;
        int ret;
        TALLOC_CTX *mem_ctx;

        ldb_debug(module->ldb, LDB_DEBUG_TRACE, "objectclass_add\n");

        if (ldb_dn_is_special(req->op.add.message->dn)) { /* do not manipulate our control entries */
                return ldb_next_request(module, req);
        }
        
        objectclass_element = ldb_msg_find_element(req->op.add.message, "objectClass");

        /* If no part of this add has an objectClass, then we don't
         * need to make any changes. cn=rootdse doesn't have an objectClass */
        if (!objectclass_element) {
                return ldb_next_request(module, req);
        }

        mem_ctx = talloc_new(req);
        if (mem_ctx == NULL) {
                return LDB_ERR_OPERATIONS_ERROR;
        }

        ret = objectclass_sort(module, mem_ctx, objectclass_element, &sorted);
        if (ret != LDB_SUCCESS) {
                return ret;
        }

        /* prepare the first operation */
        down_req = talloc(req, struct ldb_request);
        if (down_req == NULL) {
                ldb_set_errstring(module->ldb, "Out of memory!");
                talloc_free(mem_ctx);
                return LDB_ERR_OPERATIONS_ERROR;
        }

        *down_req = *req; /* copy the request */

        down_req->op.add.message = msg = ldb_msg_copy_shallow(down_req, req->op.add.message);

        if (down_req->op.add.message == NULL) {
                talloc_free(mem_ctx);
                return LDB_ERR_OPERATIONS_ERROR;
        }

        ldb_msg_remove_attr(msg, "objectClass");
        ret = ldb_msg_add_empty(msg, "objectClass", 0, NULL);
        
        if (ret != LDB_SUCCESS) {
                talloc_free(mem_ctx);
                return ret;
        }

        /* We must completely replace the existing objectClass entry,
         * because we need it sorted */

        /* Move from the linked list back into an ldb msg */
        for (current = sorted; current; current = current->next) {
                ret = ldb_msg_add_string(msg, "objectClass", current->objectclass);
                if (ret != LDB_SUCCESS) {
                        ldb_set_errstring(module->ldb, "objectclass: could not re-add sorted objectclass to modify msg");
                        talloc_free(mem_ctx);
                        return ret;
                }
        }

        talloc_free(mem_ctx);
        ret = ldb_msg_sanity_check(module->ldb, msg);

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

        /* go on with the call chain */
        ret = ldb_next_request(module, down_req);

        /* do not free down_req as the call results may be linked to it,
         * it will be freed when the upper level request get freed */
        if (ret == LDB_SUCCESS) {
                req->handle = down_req->handle;
        }
        return ret;
}

static int objectclass_modify(struct ldb_module *module, struct ldb_request *req)
{
        struct ldb_message_element *objectclass_element;
        struct ldb_message *msg;
        ldb_debug(module->ldb, LDB_DEBUG_TRACE, "objectclass_modify\n");

        if (ldb_dn_is_special(req->op.mod.message->dn)) { /* do not manipulate our control entries */
                return ldb_next_request(module, req);
        }
        
        objectclass_element = ldb_msg_find_element(req->op.mod.message, "objectClass");

        /* If no part of this touches the objectClass, then we don't
         * need to make any changes.  */
        /* If the only operation is the deletion of the objectClass then go on */
        if (!objectclass_element) {
                return ldb_next_request(module, req);
        }

        switch (objectclass_element->flags & LDB_FLAG_MOD_MASK) {
        case LDB_FLAG_MOD_DELETE:
                /* Delete everything?  Probably totally illigal, but hey! */
                if (objectclass_element->num_values == 0) {
                        return ldb_next_request(module, req);
                }
                break;
        case LDB_FLAG_MOD_REPLACE:
        {
                struct ldb_request *down_req;
                struct class_list *sorted, *current;
                TALLOC_CTX *mem_ctx;
                int ret;
                mem_ctx = talloc_new(req);
                if (mem_ctx == NULL) {
                        return LDB_ERR_OPERATIONS_ERROR;
                }

                /* prepare the first operation */
                down_req = talloc(req, struct ldb_request);
                if (down_req == NULL) {
                        ldb_set_errstring(module->ldb, "Out of memory!");
                        talloc_free(mem_ctx);
                        return LDB_ERR_OPERATIONS_ERROR;
                }
                
                *down_req = *req; /* copy the request */
                
                down_req->op.mod.message = msg = ldb_msg_copy_shallow(down_req, req->op.mod.message);
                
                if (down_req->op.add.message == NULL) {
                        talloc_free(mem_ctx);
                        return LDB_ERR_OPERATIONS_ERROR;
                }
                
                ret = objectclass_sort(module, mem_ctx, objectclass_element, &sorted);
                if (ret != LDB_SUCCESS) {
                        return ret;
                }

                /* We must completely replace the existing objectClass entry,
                 * because we need it sorted */
                
                ldb_msg_remove_attr(msg, "objectClass");
                ret = ldb_msg_add_empty(msg, "objectClass", LDB_FLAG_MOD_REPLACE, NULL);
                
                if (ret != LDB_SUCCESS) {
                        talloc_free(mem_ctx);
                        return ret;
                }

                /* Move from the linked list back into an ldb msg */
                for (current = sorted; current; current = current->next) {
                        ret = ldb_msg_add_string(msg, "objectClass", current->objectclass);
                        if (ret != LDB_SUCCESS) {
                                ldb_set_errstring(module->ldb, "objectclass: could not re-add sorted objectclass to modify msg");
                                talloc_free(mem_ctx);
                                return ret;
                        }
                }
                
                talloc_free(mem_ctx);

                ret = ldb_msg_sanity_check(module->ldb, msg);
                if (ret != LDB_SUCCESS) {
                        talloc_free(mem_ctx);
                        return ret;
                }
                
                /* go on with the call chain */
                ret = ldb_next_request(module, down_req);
                
                /* do not free down_req as the call results may be linked to it,
                 * it will be freed when the upper level request get freed */
                if (ret == LDB_SUCCESS) {
                        req->handle = down_req->handle;
                }
                return ret;
        }
        }

        {
                struct ldb_handle *h;
                struct oc_context *ac;
                
                h = oc_init_handle(req, module);
                if (!h) {
                        return LDB_ERR_OPERATIONS_ERROR;
                }
                ac = talloc_get_type(h->private_data, struct oc_context);
                
                /* return or own handle to deal with this call */
                req->handle = h;
                
                /* prepare the first operation */
                ac->down_req = talloc(ac, struct ldb_request);
                if (ac->down_req == NULL) {
                        ldb_set_errstring(module->ldb, "Out of memory!");
                        return LDB_ERR_OPERATIONS_ERROR;
                }
                
                *(ac->down_req) = *req; /* copy the request */
                
                ac->down_req->context = NULL;
                ac->down_req->callback = NULL;
                ldb_set_timeout_from_prev_req(module->ldb, req, ac->down_req);
                
                ac->step = OC_DO_REQ;

                return ldb_next_request(module, ac->down_req);
        }
}

static int get_self_callback(struct ldb_context *ldb, void *context, struct ldb_reply *ares)
{
        struct oc_context *ac;

        if (!context || !ares) {
                ldb_set_errstring(ldb, "NULL Context or Result in callback");
                return LDB_ERR_OPERATIONS_ERROR;
        }

        ac = talloc_get_type(context, struct oc_context);

        /* we are interested only in the single reply (base search) we receive here */
        if (ares->type == LDB_REPLY_ENTRY) {
                if (ac->search_res != NULL) {
                        ldb_set_errstring(ldb, "Too many results");
                        talloc_free(ares);
                        return LDB_ERR_OPERATIONS_ERROR;
                }

                ac->search_res = talloc_move(ac, &ares);
        } else {
                talloc_free(ares);
        }

        return LDB_SUCCESS;
}

static int objectclass_search_self(struct ldb_handle *h) {

        struct oc_context *ac;
        static const char * const attrs[] = { "objectClass", NULL };

        ac = talloc_get_type(h->private_data, struct oc_context);

        /* prepare the search operation */
        ac->search_req = talloc_zero(ac, struct ldb_request);
        if (ac->search_req == NULL) {
                ldb_debug(ac->module->ldb, LDB_DEBUG_ERROR, "Out of Memory!\n");
                return LDB_ERR_OPERATIONS_ERROR;
        }

        ac->search_req->operation = LDB_SEARCH;
        ac->search_req->op.search.base = ac->orig_req->op.mod.message->dn;
        ac->search_req->op.search.scope = LDB_SCOPE_BASE;
        ac->search_req->op.search.tree = ldb_parse_tree(ac->search_req, NULL);
        if (ac->search_req->op.search.tree == NULL) {
                ldb_set_errstring(ac->module->ldb, "objectclass: Internal error producing null search");
                return LDB_ERR_OPERATIONS_ERROR;
        }
        ac->search_req->op.search.attrs = attrs;
        ac->search_req->controls = NULL;
        ac->search_req->context = ac;
        ac->search_req->callback = get_self_callback;
        ldb_set_timeout_from_prev_req(ac->module->ldb, ac->orig_req, ac->search_req);

        ac->step = OC_SEARCH_SELF;

        return ldb_next_request(ac->module, ac->search_req);
}

static int objectclass_do_mod(struct ldb_handle *h) {

        struct oc_context *ac;
        struct ldb_message_element *objectclass_element;
        struct ldb_message *msg;
        TALLOC_CTX *mem_ctx;
        struct class_list *sorted, *current;
        int ret;
      
        ac = talloc_get_type(h->private_data, struct oc_context);

        mem_ctx = talloc_new(ac);
        if (mem_ctx == NULL) {
                return LDB_ERR_OPERATIONS_ERROR;
        }

        ac->mod_req = talloc(ac, struct ldb_request);
        if (ac->mod_req == NULL) {
                talloc_free(mem_ctx);
                return LDB_ERR_OPERATIONS_ERROR;
        }

        ac->mod_req->operation = LDB_MODIFY;
        ac->mod_req->controls = NULL;
        ac->mod_req->context = ac;
        ac->mod_req->callback = NULL;
        ldb_set_timeout_from_prev_req(ac->module->ldb, ac->orig_req, ac->mod_req);
        
        /* use a new message structure */
        ac->mod_req->op.mod.message = msg = ldb_msg_new(ac->mod_req);
        if (msg == NULL) {
                ldb_set_errstring(ac->module->ldb, "objectclass: could not create new modify msg");
                talloc_free(mem_ctx);
                return LDB_ERR_OPERATIONS_ERROR;
        }

        /* This is now the objectClass list from the database */
        objectclass_element = ldb_msg_find_element(ac->search_res->message, 
                                                   "objectClass");
        if (!objectclass_element) {
                /* Where did it go?  Move along now, nothing to see here */
                talloc_free(mem_ctx);
                return LDB_SUCCESS;
        }
        
        /* modify dn */
        msg->dn = ac->orig_req->op.mod.message->dn;

        ret = objectclass_sort(ac->module, mem_ctx, objectclass_element, &sorted);
        if (ret != LDB_SUCCESS) {
                return ret;
        }

        /* We must completely replace the existing objectClass entry.
         * We could do a constrained add/del, but we are meant to be
         * in a transaction... */

        ret = ldb_msg_add_empty(msg, "objectClass", LDB_FLAG_MOD_REPLACE, NULL);
        if (ret != LDB_SUCCESS) {
                ldb_set_errstring(ac->module->ldb, "objectclass: could not clear objectclass in modify msg");
                talloc_free(mem_ctx);
                return ret;
        }
        
        /* Move from the linked list back into an ldb msg */
        for (current = sorted; current; current = current->next) {
                ret = ldb_msg_add_string(msg, "objectClass", current->objectclass);
                if (ret != LDB_SUCCESS) {
                        ldb_set_errstring(ac->module->ldb, "objectclass: could not re-add sorted objectclass to modify msg");
                        talloc_free(mem_ctx);
                        return ret;
                }
        }

        ret = ldb_msg_sanity_check(ac->module->ldb, msg);
        if (ret != LDB_SUCCESS) {
                talloc_free(mem_ctx);
                return ret;
        }


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

        ac->step = OC_DO_MOD;

        talloc_free(mem_ctx);
        /* perform the search */
        return ldb_next_request(ac->module, ac->mod_req);
}

static int oc_wait(struct ldb_handle *handle) {
        struct oc_context *ac;
        int ret;
    
        if (!handle || !handle->private_data) {
                return LDB_ERR_OPERATIONS_ERROR;
        }

        if (handle->state == LDB_ASYNC_DONE) {
                return handle->status;
        }

        handle->state = LDB_ASYNC_PENDING;
        handle->status = LDB_SUCCESS;

        ac = talloc_get_type(handle->private_data, struct oc_context);

        switch (ac->step) {
        case OC_DO_REQ:
                ret = ldb_wait(ac->down_req->handle, LDB_WAIT_NONE);

                if (ret != LDB_SUCCESS) {
                        handle->status = ret;
                        goto done;
                }
                if (ac->down_req->handle->status != LDB_SUCCESS) {
                        handle->status = ac->down_req->handle->status;
                        goto done;
                }

                if (ac->down_req->handle->state != LDB_ASYNC_DONE) {
                        return LDB_SUCCESS;
                }

                /* mods done, go on */
                return objectclass_search_self(handle);

        case OC_SEARCH_SELF:
                ret = ldb_wait(ac->search_req->handle, LDB_WAIT_NONE);

                if (ret != LDB_SUCCESS) {
                        handle->status = ret;
                        goto done;
                }
                if (ac->search_req->handle->status != LDB_SUCCESS) {
                        handle->status = ac->search_req->handle->status;
                        goto done;
                }

                if (ac->search_req->handle->state != LDB_ASYNC_DONE) {
                        return LDB_SUCCESS;
                }

                /* self search done, go on */
                return objectclass_do_mod(handle);

        case OC_DO_MOD:
                ret = ldb_wait(ac->mod_req->handle, LDB_WAIT_NONE);

                if (ret != LDB_SUCCESS) {
                        handle->status = ret;
                        goto done;
                }
                if (ac->mod_req->handle->status != LDB_SUCCESS) {
                        handle->status = ac->mod_req->handle->status;
                        goto done;
                }

                if (ac->mod_req->handle->state != LDB_ASYNC_DONE) {
                        return LDB_SUCCESS;
                }

                break;
                
        default:
                ret = LDB_ERR_OPERATIONS_ERROR;
                goto done;
        }

        ret = LDB_SUCCESS;

done:
        handle->state = LDB_ASYNC_DONE;
        return ret;
}

static int oc_wait_all(struct ldb_handle *handle) {

        int ret;

        while (handle->state != LDB_ASYNC_DONE) {
                ret = oc_wait(handle);
                if (ret != LDB_SUCCESS) {
                        return ret;
                }
        }

        return handle->status;
}

static int objectclass_wait(struct ldb_handle *handle, enum ldb_wait_type type)
{
        if (type == LDB_WAIT_ALL) {
                return oc_wait_all(handle);
        } else {
                return oc_wait(handle);
        }
}

static const struct ldb_module_ops objectclass_ops = {
        .name              = "objectclass",
        .add           = objectclass_add,
        .modify        = objectclass_modify,
        .wait          = objectclass_wait
};

int ldb_objectclass_init(void)
{
        return ldb_register_module(&objectclass_ops);
}