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ldb_match.c

/* 
   ldb database library

   Copyright (C) Andrew Tridgell  2004-2005
   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 expression matching
 *
 *  Description: ldb expression matching 
 *
 *  Author: Andrew Tridgell
 */

#include "ldb_includes.h"

/*
  check if the scope matches in a search result
*/
static int ldb_match_scope(struct ldb_context *ldb,
                     struct ldb_dn *base,
                     struct ldb_dn *dn,
                     enum ldb_scope scope)
{
      int ret = 0;

      if (base == NULL || dn == NULL) {
            return 1;
      }

      switch (scope) {
      case LDB_SCOPE_BASE:
            if (ldb_dn_compare(base, dn) == 0) {
                  ret = 1;
            }
            break;

      case LDB_SCOPE_ONELEVEL:
            if (ldb_dn_get_comp_num(dn) == (ldb_dn_get_comp_num(base) + 1)) {
                  if (ldb_dn_compare_base(base, dn) == 0) {
                        ret = 1;
                  }
            }
            break;
            
      case LDB_SCOPE_SUBTREE:
      default:
            if (ldb_dn_compare_base(base, dn) == 0) {
                  ret = 1;
            }
            break;
      }

      return ret;
}


/*
  match if node is present
*/
static int ldb_match_present(struct ldb_context *ldb, 
                       const struct ldb_message *msg,
                       const struct ldb_parse_tree *tree,
                       enum ldb_scope scope)
{
      if (ldb_attr_dn(tree->u.present.attr) == 0) {
            return 1;
      }

      if (ldb_msg_find_element(msg, tree->u.present.attr)) {
            return 1;
      }

      return 0;
}

static int ldb_match_comparison(struct ldb_context *ldb, 
                        const struct ldb_message *msg,
                        const struct ldb_parse_tree *tree,
                        enum ldb_scope scope,
                        enum ldb_parse_op comp_op)
{
      unsigned int i;
      struct ldb_message_element *el;
      const struct ldb_schema_attribute *a;
      int ret;

      /* FIXME: APPROX comparison not handled yet */
      if (comp_op == LDB_OP_APPROX) return 0;

      el = ldb_msg_find_element(msg, tree->u.comparison.attr);
      if (el == NULL) {
            return 0;
      }

      a = ldb_schema_attribute_by_name(ldb, el->name);

      for (i = 0; i < el->num_values; i++) {
            ret = a->syntax->comparison_fn(ldb, ldb, &el->values[i], &tree->u.comparison.value);

            if (ret == 0) {
                  return 1;
            }
            if (ret > 0 && comp_op == LDB_OP_GREATER) {
                  return 1;
            }
            if (ret < 0 && comp_op == LDB_OP_LESS) {
                  return 1;
            }
      }

      return 0;
}

/*
  match a simple leaf node
*/
static int ldb_match_equality(struct ldb_context *ldb, 
                        const struct ldb_message *msg,
                        const struct ldb_parse_tree *tree,
                        enum ldb_scope scope)
{
      unsigned int i;
      struct ldb_message_element *el;
      const struct ldb_schema_attribute *a;
      struct ldb_dn *valuedn;
      int ret;

      if (ldb_attr_dn(tree->u.equality.attr) == 0) {
            valuedn = ldb_dn_new(ldb, ldb, (char *)tree->u.equality.value.data);
            if (valuedn == NULL) {
                  return 0;
            }

            ret = ldb_dn_compare(msg->dn, valuedn);

            talloc_free(valuedn);

            if (ret == 0) return 1;
            return 0;
      }

      /* TODO: handle the "*" case derived from an extended search
         operation without the attibute type defined */
      el = ldb_msg_find_element(msg, tree->u.equality.attr);
      if (el == NULL) {
            return 0;
      }

      a = ldb_schema_attribute_by_name(ldb, el->name);

      for (i=0;i<el->num_values;i++) {
            if (a->syntax->comparison_fn(ldb, ldb, &tree->u.equality.value, 
                                   &el->values[i]) == 0) {
                  return 1;
            }
      }

      return 0;
}

static int ldb_wildcard_compare(struct ldb_context *ldb,
                        const struct ldb_parse_tree *tree,
                        const struct ldb_val value)
{
      const struct ldb_schema_attribute *a;
      struct ldb_val val;
      struct ldb_val cnk;
      struct ldb_val *chunk;
      char *p, *g;
      uint8_t *save_p = NULL;
      int c = 0;

      a = ldb_schema_attribute_by_name(ldb, tree->u.substring.attr);

      if(a->syntax->canonicalise_fn(ldb, ldb, &value, &val) != 0)
            return -1;

      save_p = val.data;
      cnk.data = NULL;

      if ( ! tree->u.substring.start_with_wildcard ) {

            chunk = tree->u.substring.chunks[c];
            if(a->syntax->canonicalise_fn(ldb, ldb, chunk, &cnk) != 0) goto failed;

            /* This deals with wildcard prefix searches on binary attributes (eg objectGUID) */
            if (cnk.length > val.length) {
                  goto failed;
            }
            if (memcmp((char *)val.data, (char *)cnk.data, cnk.length) != 0) goto failed;
            val.length -= cnk.length;
            val.data += cnk.length;
            c++;
            talloc_free(cnk.data);
            cnk.data = NULL;
      }

      while (tree->u.substring.chunks[c]) {

            chunk = tree->u.substring.chunks[c];
            if(a->syntax->canonicalise_fn(ldb, ldb, chunk, &cnk) != 0) goto failed;

            /* FIXME: case of embedded nulls */
            p = strstr((char *)val.data, (char *)cnk.data);
            if (p == NULL) goto failed;
            if ( (! tree->u.substring.chunks[c + 1]) && (! tree->u.substring.end_with_wildcard) ) {
                  do { /* greedy */
                        g = strstr((char *)p + cnk.length, (char *)cnk.data);
                        if (g) p = g;
                  } while(g);
            }
            val.length = val.length - (p - (char *)(val.data)) - cnk.length;
            val.data = (uint8_t *)(p + cnk.length);
            c++;
            talloc_free(cnk.data);
            cnk.data = NULL;
      }

      if ( (! tree->u.substring.end_with_wildcard) && (*(val.data) != 0) ) goto failed; /* last chunk have not reached end of string */
      talloc_free(save_p);
      return 1;

failed:
      talloc_free(save_p);
      talloc_free(cnk.data);
      return 0;
}

/*
  match a simple leaf node
*/
static int ldb_match_substring(struct ldb_context *ldb, 
                         const struct ldb_message *msg,
                         const struct ldb_parse_tree *tree,
                         enum ldb_scope scope)
{
      unsigned int i;
      struct ldb_message_element *el;

      el = ldb_msg_find_element(msg, tree->u.substring.attr);
      if (el == NULL) {
            return 0;
      }

      for (i = 0; i < el->num_values; i++) {
            if (ldb_wildcard_compare(ldb, tree, el->values[i]) == 1) {
                  return 1;
            }
      }

      return 0;
}


/*
  bitwise-and comparator
*/
static int ldb_comparator_and(const struct ldb_val *v1, const struct ldb_val *v2)
{
      uint64_t i1, i2;
      i1 = strtoull((char *)v1->data, NULL, 0);
      i2 = strtoull((char *)v2->data, NULL, 0);
      return ((i1 & i2) == i2);
}

/*
  bitwise-or comparator
*/
static int ldb_comparator_or(const struct ldb_val *v1, const struct ldb_val *v2)
{
      uint64_t i1, i2;
      i1 = strtoull((char *)v1->data, NULL, 0);
      i2 = strtoull((char *)v2->data, NULL, 0);
      return ((i1 & i2) != 0);
}


/*
  extended match, handles things like bitops
*/
static int ldb_match_extended(struct ldb_context *ldb, 
                        const struct ldb_message *msg,
                        const struct ldb_parse_tree *tree,
                        enum ldb_scope scope)
{
      int i;
      const struct {
            const char *oid;
            int (*comparator)(const struct ldb_val *, const struct ldb_val *);
      } rules[] = {
            { LDB_OID_COMPARATOR_AND, ldb_comparator_and},
            { LDB_OID_COMPARATOR_OR, ldb_comparator_or}
      };
      int (*comp)(const struct ldb_val *, const struct ldb_val *) = NULL;
      struct ldb_message_element *el;

      if (tree->u.extended.dnAttributes) {
            ldb_debug(ldb, LDB_DEBUG_ERROR, "ldb: dnAttributes extended match not supported yet");
            return -1;
      }
      if (tree->u.extended.rule_id == NULL) {
            ldb_debug(ldb, LDB_DEBUG_ERROR, "ldb: no-rule extended matches not supported yet");
            return -1;
      }
      if (tree->u.extended.attr == NULL) {
            ldb_debug(ldb, LDB_DEBUG_ERROR, "ldb: no-attribute extended matches not supported yet");
            return -1;
      }

      for (i=0;i<ARRAY_SIZE(rules);i++) {
            if (strcmp(rules[i].oid, tree->u.extended.rule_id) == 0) {
                  comp = rules[i].comparator;
                  break;
            }
      }
      if (comp == NULL) {
            ldb_debug(ldb, LDB_DEBUG_ERROR, "ldb: unknown extended rule_id %s\n",
                    tree->u.extended.rule_id);
            return -1;
      }

      /* find the message element */
      el = ldb_msg_find_element(msg, tree->u.extended.attr);
      if (el == NULL) {
            return 0;
      }

      for (i=0;i<el->num_values;i++) {
            int ret = comp(&el->values[i], &tree->u.extended.value);
            if (ret == -1 || ret == 1) return ret;
      }

      return 0;
}

/*
  return 0 if the given parse tree matches the given message. Assumes
  the message is in sorted order

  return 1 if it matches, and 0 if it doesn't match

  this is a recursive function, and does short-circuit evaluation
 */
static int ldb_match_message(struct ldb_context *ldb, 
                       const struct ldb_message *msg,
                       const struct ldb_parse_tree *tree,
                       enum ldb_scope scope)
{
      unsigned int i;
      int v;

      switch (tree->operation) {
      case LDB_OP_AND:
            for (i=0;i<tree->u.list.num_elements;i++) {
                  v = ldb_match_message(ldb, msg, tree->u.list.elements[i], scope);
                  if (!v) return 0;
            }
            return 1;

      case LDB_OP_OR:
            for (i=0;i<tree->u.list.num_elements;i++) {
                  v = ldb_match_message(ldb, msg, tree->u.list.elements[i], scope);
                  if (v) return 1;
            }
            return 0;

      case LDB_OP_NOT:
            return ! ldb_match_message(ldb, msg, tree->u.isnot.child, scope);

      case LDB_OP_EQUALITY:
            return ldb_match_equality(ldb, msg, tree, scope);

      case LDB_OP_SUBSTRING:
            return ldb_match_substring(ldb, msg, tree, scope);

      case LDB_OP_GREATER:
            return ldb_match_comparison(ldb, msg, tree, scope, LDB_OP_GREATER);

      case LDB_OP_LESS:
            return ldb_match_comparison(ldb, msg, tree, scope, LDB_OP_LESS);

      case LDB_OP_PRESENT:
            return ldb_match_present(ldb, msg, tree, scope);

      case LDB_OP_APPROX:
            return ldb_match_comparison(ldb, msg, tree, scope, LDB_OP_APPROX);

      case LDB_OP_EXTENDED:
            return ldb_match_extended(ldb, msg, tree, scope);

      }

      return 0;
}

int ldb_match_msg(struct ldb_context *ldb,
              const struct ldb_message *msg,
              const struct ldb_parse_tree *tree,
              struct ldb_dn *base,
              enum ldb_scope scope)
{
      if ( ! ldb_match_scope(ldb, base, msg->dn, scope) ) {
            return 0;
      }

      return ldb_match_message(ldb, msg, tree, scope);
}

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