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sort.c

/* 
   ldb database library

   Copyright (C) Simo Sorce  2005

     ** 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 server side sort control module
 *
 *  Description: this module sorts the results of a search
 *
 *  Author: Simo Sorce
 */

#include "ldb_includes.h"

struct opaque {
      struct ldb_context *ldb;
      const struct ldb_attrib_handler *h;
      const char *attribute;
      int reverse;
      int result;
};

struct sort_context {
      struct ldb_module *module;
      void *up_context;
      int (*up_callback)(struct ldb_context *, void *, struct ldb_reply *);

      char *attributeName;
      char *orderingRule;
      int reverse;

      struct ldb_request *req;
      struct ldb_message **msgs;
      char **referrals;
      struct ldb_control **controls;
      int num_msgs;
      int num_refs;

      const struct ldb_schema_attribute *a;
      int sort_result;
};

static struct ldb_handle *init_handle(void *mem_ctx, struct ldb_module *module,
                                  void *context,
                                  int (*callback)(struct ldb_context *, void *, struct ldb_reply *))
{
      struct sort_context *ac;
      struct ldb_handle *h;

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

      h->module = module;

      ac = talloc_zero(h, struct sort_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->up_context = context;
      ac->up_callback = callback;

      return h;
}

static int build_response(void *mem_ctx, struct ldb_control ***ctrls, int result, const char *desc)
{
      struct ldb_control **controls;
      struct ldb_sort_resp_control *resp;
      int i;

      if (*ctrls) {
            controls = *ctrls;
            for (i = 0; controls[i]; i++);
            controls = talloc_realloc(mem_ctx, controls, struct ldb_control *, i + 2);
      } else {
            i = 0;
            controls = talloc_array(mem_ctx, struct ldb_control *, 2);
      }
      if (! controls )
            return LDB_ERR_OPERATIONS_ERROR;

      *ctrls = controls;

      controls[i+1] = NULL;
      controls[i] = talloc(controls, struct ldb_control);
      if (! controls[i] )
            return LDB_ERR_OPERATIONS_ERROR;

      controls[i]->oid = LDB_CONTROL_SORT_RESP_OID;
      controls[i]->critical = 0;

      resp = talloc(controls[i], struct ldb_sort_resp_control);
      if (! resp )
            return LDB_ERR_OPERATIONS_ERROR;

      resp->result = result;
      resp->attr_desc = talloc_strdup(resp, desc);

      if (! resp->attr_desc )
            return LDB_ERR_OPERATIONS_ERROR;
      
      controls[i]->data = resp;

      return LDB_SUCCESS;
}

static int sort_compare(struct ldb_message **msg1, struct ldb_message **msg2, void *opaque)
{
      struct sort_context *ac = talloc_get_type(opaque, struct sort_context);
      struct ldb_message_element *el1, *el2;

      if (ac->sort_result != 0) {
            /* an error occurred previously,
             * let's exit the sorting by returning always 0 */
            return 0;
      }

      el1 = ldb_msg_find_element(*msg1, ac->attributeName);
      el2 = ldb_msg_find_element(*msg2, ac->attributeName);

      if (!el1 || !el2) {
            /* the attribute was not found return and
             * set an error */
            ac->sort_result = 53;
            return 0;
      }

      if (ac->reverse)
            return ac->a->syntax->comparison_fn(ac->module->ldb, ac, &el2->values[0], &el1->values[0]);

      return ac->a->syntax->comparison_fn(ac->module->ldb, ac, &el1->values[0], &el2->values[0]);
}

static int server_sort_search_callback(struct ldb_context *ldb, void *context, struct ldb_reply *ares)
{
      struct sort_context *ac = NULL;
      
      if (!context || !ares) {
            ldb_set_errstring(ldb, "NULL Context or Result in callback");
            goto error;
      }     

            ac = talloc_get_type(context, struct sort_context);

      if (ares->type == LDB_REPLY_ENTRY) {
            ac->msgs = talloc_realloc(ac, ac->msgs, struct ldb_message *, ac->num_msgs + 2);
            if (! ac->msgs) {
                  goto error;
            }

            ac->msgs[ac->num_msgs + 1] = NULL;

            ac->msgs[ac->num_msgs] = talloc_move(ac->msgs, &ares->message);
            ac->num_msgs++;
      }

      if (ares->type == LDB_REPLY_REFERRAL) {
            ac->referrals = talloc_realloc(ac, ac->referrals, char *, ac->num_refs + 2);
            if (! ac->referrals) {
                  goto error;
            }

            ac->referrals[ac->num_refs + 1] = NULL;
            ac->referrals[ac->num_refs] = talloc_move(ac->referrals, &ares->referral);

            ac->num_refs++;
      }

      if (ares->type == LDB_REPLY_DONE) {
            ac->controls = talloc_move(ac, &ares->controls);
      }

      talloc_free(ares);
      return LDB_SUCCESS;

error:
      talloc_free(ares);
      return LDB_ERR_OPERATIONS_ERROR;
}

static int server_sort_search(struct ldb_module *module, struct ldb_request *req)
{
      struct ldb_control *control;
      struct ldb_server_sort_control **sort_ctrls;
      struct ldb_control **saved_controls;
      struct sort_context *ac;
      struct ldb_handle *h;
      int ret;

      /* check if there's a paged request control */
      control = ldb_request_get_control(req, LDB_CONTROL_SERVER_SORT_OID);
      if (control == NULL) {
            /* not found go on */
            return ldb_next_request(module, req);
      }

      req->handle = NULL;

      if (!req->callback || !req->context) {
            ldb_set_errstring(module->ldb,
                          "Async interface called with NULL callback function or NULL context");
            return LDB_ERR_OPERATIONS_ERROR;
      }
      
      h = init_handle(req, module, req->context, req->callback);
      if (!h) {
            return LDB_ERR_OPERATIONS_ERROR;
      }
      ac = talloc_get_type(h->private_data, struct sort_context);

      sort_ctrls = talloc_get_type(control->data, struct ldb_server_sort_control *);
      if (!sort_ctrls) {
            return LDB_ERR_PROTOCOL_ERROR;
      }

      /* FIXME: we do not support more than one attribute for sorting right now */
      /* FIXME: we need to check if the attribute type exist or return an error */
            
      if (sort_ctrls[1] != NULL) {
            if (control->critical) {
                  struct ldb_reply *ares;

                  ares = talloc_zero(req, struct ldb_reply);
                  if (!ares)
                        return LDB_ERR_OPERATIONS_ERROR;

                  /* 53 = unwilling to perform */
                  ares->type = LDB_REPLY_DONE;
                  if ((ret = build_response(ares, &ares->controls, 53, "sort control is not complete yet")) != LDB_SUCCESS) {
                        return ret;
                  }

                  h->status = LDB_ERR_UNSUPPORTED_CRITICAL_EXTENSION;
                  h->state = LDB_ASYNC_DONE;
                  ret = ac->up_callback(module->ldb, ac->up_context, ares);

                  return ret;
            } else {
                  /* just pass the call down and don't do any sorting */
                  ldb_next_request(module, req);
            }
      }

      ac->attributeName = sort_ctrls[0]->attributeName;
      ac->orderingRule = sort_ctrls[0]->orderingRule;
      ac->reverse = sort_ctrls[0]->reverse;

      ac->req = talloc(req, struct ldb_request);
      if (!ac->req)
            return LDB_ERR_OPERATIONS_ERROR;

      ac->req->operation = req->operation;
      ac->req->op.search.base = req->op.search.base;
      ac->req->op.search.scope = req->op.search.scope;
      ac->req->op.search.tree = req->op.search.tree;
      ac->req->op.search.attrs = req->op.search.attrs;
      ac->req->controls = req->controls;

      /* save it locally and remove it from the list */
      /* we do not need to replace them later as we
       * are keeping the original req intact */
      if (!save_controls(control, ac->req, &saved_controls)) {
            return LDB_ERR_OPERATIONS_ERROR;
      }

      ac->req->context = ac;
      ac->req->callback = server_sort_search_callback;
      ldb_set_timeout_from_prev_req(module->ldb, req, ac->req);

      req->handle = h;

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

static int server_sort_results(struct ldb_handle *handle)
{
      struct sort_context *ac;
      struct ldb_reply *ares;
      int i, ret;

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

      ac->a = ldb_schema_attribute_by_name(ac->module->ldb, ac->attributeName);
      ac->sort_result = 0;

      ldb_qsort(ac->msgs, ac->num_msgs,
              sizeof(struct ldb_message *),
              ac, (ldb_qsort_cmp_fn_t)sort_compare);

      for (i = 0; i < ac->num_msgs; i++) {
            ares = talloc_zero(ac, struct ldb_reply);
            if (!ares) {
                  handle->status = LDB_ERR_OPERATIONS_ERROR;
                  return handle->status;
            }

            ares->type = LDB_REPLY_ENTRY;
            ares->message = talloc_move(ares, &ac->msgs[i]);
            
            handle->status = ac->up_callback(ac->module->ldb, ac->up_context, ares);
            if (handle->status != LDB_SUCCESS) {
                  return handle->status;
            }
      }

      for (i = 0; i < ac->num_refs; i++) {
            ares = talloc_zero(ac, struct ldb_reply);
            if (!ares) {
                  handle->status = LDB_ERR_OPERATIONS_ERROR;
                  return handle->status;
            }

            ares->type = LDB_REPLY_REFERRAL;
            ares->referral = talloc_move(ares, &ac->referrals[i]);
            
            handle->status = ac->up_callback(ac->module->ldb, ac->up_context, ares);
            if (handle->status != LDB_SUCCESS) {
                  return handle->status;
            }
      }

      ares = talloc_zero(ac, struct ldb_reply);
      if (!ares) {
            handle->status = LDB_ERR_OPERATIONS_ERROR;
            return handle->status;
      }

      ares->type = LDB_REPLY_DONE;
      ares->controls = talloc_move(ares, &ac->controls);
            
      handle->status = ac->up_callback(ac->module->ldb, ac->up_context, ares);
      if (handle->status != LDB_SUCCESS) {
            return handle->status;
      }

      if ((ret = build_response(ac, &ac->controls, ac->sort_result, "sort control is not complete yet")) != LDB_SUCCESS) {
            return ret;
      }

      return LDB_SUCCESS;
}

static int server_sort_wait(struct ldb_handle *handle, enum ldb_wait_type type)
{
      struct sort_context *ac;
      int ret;
    
      if (!handle || !handle->private_data) {
            return LDB_ERR_OPERATIONS_ERROR;
      }

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

      ret = ldb_wait(ac->req->handle, type);

      if (ret != LDB_SUCCESS) {
            handle->status = ret;
            return ret;
      }
            
      handle->state = ac->req->handle->state;
      handle->status = ac->req->handle->status;

      if (handle->status != LDB_SUCCESS) {
            return handle->status;
      }

      if (handle->state == LDB_ASYNC_DONE) {
            ret = server_sort_results(handle);
      }

      return ret;
}

static int server_sort_init(struct ldb_module *module)
{
      struct ldb_request *req;
      int ret;

      req = talloc(module, struct ldb_request);
      if (req == NULL) {
            return LDB_ERR_OPERATIONS_ERROR;
      }

      req->operation = LDB_REQ_REGISTER_CONTROL;
      req->op.reg_control.oid = LDB_CONTROL_SERVER_SORT_OID;
      req->controls = NULL;

      ret = ldb_request(module->ldb, req);
      if (ret != LDB_SUCCESS) {
            ldb_debug(module->ldb, LDB_DEBUG_WARNING, "server_sort: Unable to register control with rootdse!\n");
      }

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

static const struct ldb_module_ops server_sort_ops = {
      .name          = "server_sort",
      .search            = server_sort_search,
      .wait              = server_sort_wait,
      .init_context        = server_sort_init
};

int ldb_sort_init(void)
{
      return ldb_register_module(&server_sort_ops);
}

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