r16774: This patch modifies the tdb API to allow the logging function to be used
[ira/wip.git] / source / lib / ldb / ldb_tdb / ldb_tdb.c
index 17931352f7569211207af86fbb527d19d02e3d79..15f34db5e1595a28d44698510d3dddcb48adee92 100644 (file)
@@ -2,6 +2,9 @@
    ldb database library
 
    Copyright (C) Andrew Tridgell  2004
+   Copyright (C) Stefan Metzmacher  2004
+   Copyright (C) Simo Sorce       2006
+   
 
      ** NOTE! The following LGPL license applies to the ldb
      ** library. This does NOT imply that all of Samba is released
 */
 
 /*
- *  Name: ldb
+ *  Name: ldb_tdb
  *
  *  Component: ldb tdb backend
  *
  *  Description: core functions for tdb backend
  *
  *  Author: Andrew Tridgell
+ *  Author: Stefan Metzmacher
+ *
+ *  Modifications:
+ *
+ *  - description: make the module use asyncronous calls
+ *    date: Feb 2006
+ *    Author: Simo Sorce
  */
 
 #include "includes.h"
-#include "ldb_tdb/ldb_tdb.h"
+#include "ldb/include/includes.h"
+
+#include "ldb/ldb_tdb/ldb_tdb.h"
+
+
+/*
+  map a tdb error code to a ldb error code
+*/
+static int ltdb_err_map(enum TDB_ERROR tdb_code)
+{
+       switch (tdb_code) {
+       case TDB_SUCCESS:
+               return LDB_SUCCESS;
+       case TDB_ERR_CORRUPT:
+       case TDB_ERR_OOM:
+       case TDB_ERR_EINVAL:
+               return LDB_ERR_OPERATIONS_ERROR;
+       case TDB_ERR_IO:
+               return LDB_ERR_PROTOCOL_ERROR;
+       case TDB_ERR_LOCK:
+       case TDB_ERR_NOLOCK:
+               return LDB_ERR_BUSY;
+       case TDB_ERR_LOCK_TIMEOUT:
+               return LDB_ERR_TIME_LIMIT_EXCEEDED;
+       case TDB_ERR_EXISTS:
+               return LDB_ERR_ENTRY_ALREADY_EXISTS;
+       case TDB_ERR_NOEXIST:
+               return LDB_ERR_NO_SUCH_OBJECT;
+       case TDB_ERR_RDONLY:
+               return LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS;
+       }
+       return LDB_ERR_OTHER;
+}
+
+
+struct ldb_async_handle *init_ltdb_handle(struct ltdb_private *ltdb, struct ldb_module *module,
+                                         void *context,
+                                         int (*callback)(struct ldb_context *, void *, struct ldb_async_result *))
+{
+       struct ltdb_async_context *ac;
+       struct ldb_async_handle *h;
+
+       h = talloc_zero(ltdb, struct ldb_async_handle);
+       if (h == NULL) {
+               ldb_set_errstring(module->ldb, talloc_asprintf(module, "Out of Memory"));
+               return NULL;
+       }
+
+       h->module = module;
+
+       ac = talloc_zero(h, struct ltdb_async_context);
+       if (ac == NULL) {
+               ldb_set_errstring(module->ldb, talloc_asprintf(module, "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->context = context;
+       ac->callback = callback;
+
+       return h;
+}
 
 /*
   form a TDB_DATA for a record key
   caller frees
+
+  note that the key for a record can depend on whether the 
+  dn refers to a case sensitive index record or not
 */
-struct TDB_DATA ltdb_key(const char *dn)
+struct TDB_DATA ltdb_key(struct ldb_module *module, const struct ldb_dn *dn)
 {
+       struct ldb_context *ldb = module->ldb;
        TDB_DATA key;
        char *key_str = NULL;
+       char *dn_folded = NULL;
+
+       /*
+         most DNs are case insensitive. The exception is index DNs for
+         case sensitive attributes
+
+         there are 3 cases dealt with in this code:
+
+         1) if the dn doesn't start with @ then uppercase the attribute
+             names and the attributes values of case insensitive attributes
+         2) if the dn starts with @ then leave it alone - the indexing code handles
+            the rest
+       */
+
+       dn_folded = ldb_dn_linearize_casefold(ldb, dn);
+       if (!dn_folded) {
+               goto failed;
+       }
+
+       key_str = talloc_asprintf(ldb, "DN=%s", dn_folded);
+
+       talloc_free(dn_folded);
 
-       asprintf(&key_str, "DN=%s", dn);
        if (!key_str) {
-               errno = ENOMEM;
-               key.dptr = NULL;
-               key.dsize = 0;
-               return key;
+               goto failed;
        }
 
-       key.dptr = key_str;
-       key.dsize = strlen(key_str)+1;
+       key.dptr = (uint8_t *)key_str;
+       key.dsize = strlen(key_str) + 1;
 
        return key;
+
+failed:
+       errno = ENOMEM;
+       key.dptr = NULL;
+       key.dsize = 0;
+       return key;
+}
+
+/*
+  check special dn's have valid attributes
+  currently only @ATTRIBUTES is checked
+*/
+int ltdb_check_special_dn(struct ldb_module *module, const struct ldb_message *msg)
+{
+       int i, j;
+       if (! ldb_dn_is_special(msg->dn) ||
+           ! ldb_dn_check_special(msg->dn, LTDB_ATTRIBUTES)) {
+               return 0;
+       }
+
+       /* we have @ATTRIBUTES, let's check attributes are fine */
+       /* should we check that we deny multivalued attributes ? */
+       for (i = 0; i < msg->num_elements; i++) {
+               for (j = 0; j < msg->elements[i].num_values; j++) {
+                       if (ltdb_check_at_attributes_values(&msg->elements[i].values[j]) != 0) {
+                               char *err_string = talloc_strdup(module, "Invalid attribute value in an @ATTRIBUTES entry");
+                               if (err_string) {
+                                       ldb_set_errstring(module->ldb, err_string);
+                               }
+                               return LDB_ERR_INVALID_ATTRIBUTE_SYNTAX;
+                       }
+               }
+       }
+
+       return 0;
 }
 
 
+/*
+  we've made a modification to a dn - possibly reindex and 
+  update sequence number
+*/
+static int ltdb_modified(struct ldb_module *module, const struct ldb_dn *dn)
+{
+       int ret = 0;
+
+       if (ldb_dn_is_special(dn) &&
+           (ldb_dn_check_special(dn, LTDB_INDEXLIST) ||
+            ldb_dn_check_special(dn, LTDB_ATTRIBUTES)) ) {
+               ret = ltdb_reindex(module);
+       }
+
+       if (ret == 0 &&
+           !(ldb_dn_is_special(dn) &&
+             ldb_dn_check_special(dn, LTDB_BASEINFO)) ) {
+               ret = ltdb_increase_sequence_number(module);
+       }
+
+       return ret;
+}
+
 /*
   store a record into the db
 */
-int ltdb_store(struct ldb_context *ldb, const struct ldb_message *msg, int flgs)
+int ltdb_store(struct ldb_module *module, const struct ldb_message *msg, int flgs)
 {
-       struct ltdb_private *ltdb = ldb->private;
+       struct ltdb_private *ltdb = module->private_data;
        TDB_DATA tdb_key, tdb_data;
        int ret;
 
-       tdb_key = ltdb_key(msg->dn);
+       tdb_key = ltdb_key(module, msg->dn);
        if (!tdb_key.dptr) {
-               return -1;
+               return LDB_ERR_OTHER;
        }
 
-       ret = ltdb_pack_data(ldb, msg, &tdb_data);
+       ret = ltdb_pack_data(module, msg, &tdb_data);
        if (ret == -1) {
-               free(tdb_key.dptr);
-               return -1;
+               talloc_free(tdb_key.dptr);
+               return LDB_ERR_OTHER;
        }
 
        ret = tdb_store(ltdb->tdb, tdb_key, tdb_data, flgs);
        if (ret == -1) {
+               ret = ltdb_err_map(tdb_error(ltdb->tdb));
                goto done;
        }
        
-       ret = ltdb_index_add(ldb, msg);
+       ret = ltdb_index_add(module, msg);
        if (ret == -1) {
                tdb_delete(ltdb->tdb, tdb_key);
        }
 
 done:
-       free(tdb_key.dptr);
-       free(tdb_data.dptr);
+       talloc_free(tdb_key.dptr);
+       talloc_free(tdb_data.dptr);
 
        return ret;
 }
 
 
+static int ltdb_add_internal(struct ldb_module *module, const struct ldb_message *msg)
+{
+       int ret;
+       
+       ret = ltdb_check_special_dn(module, msg);
+       if (ret != LDB_SUCCESS) {
+               return ret;
+       }
+       
+       if (ltdb_cache_load(module) != 0) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       ret = ltdb_store(module, msg, TDB_INSERT);
+       if (ret != LDB_SUCCESS) {
+               return ret;
+       }
+
+       ret = ltdb_modified(module, msg->dn);
+       if (ret != LDB_SUCCESS) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       return LDB_SUCCESS;
+}
+
 /*
   add a record to the database
 */
-static int ltdb_add(struct ldb_context *ldb, const struct ldb_message *msg)
+static int ltdb_add(struct ldb_module *module, struct ldb_request *req)
 {
-       return ltdb_store(ldb, msg, TDB_INSERT);
-}
+       struct ltdb_private *ltdb = talloc_get_type(module->private_data, struct ltdb_private);
+       struct ltdb_async_context *ltdb_ac;
+       int tret, ret = LDB_SUCCESS;
 
+       if (req->controls != NULL) {
+               ldb_debug(module->ldb, LDB_DEBUG_WARNING, "Controls should not reach the ldb_tdb backend!\n");
+               if (check_critical_controls(req->controls)) {
+                       return LDB_ERR_UNSUPPORTED_CRITICAL_EXTENSION;
+               }
+       }
+       
+       req->async.handle = init_ltdb_handle(ltdb, module, req->async.context, req->async.callback);
+       if (req->async.handle == NULL) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       ltdb_ac = talloc_get_type(req->async.handle->private_data, struct ltdb_async_context);
+
+       tret = ltdb_add_internal(module, req->op.add.message);
+       if (tret != LDB_SUCCESS) {
+               req->async.handle->status = tret;
+               goto done;
+       }
+       
+       if (ltdb_ac->callback) {
+               ret = ltdb_ac->callback(module->ldb, ltdb_ac->context, NULL);
+       }
+done:
+       req->async.handle->state = LDB_ASYNC_DONE;
+       return ret;
+}
 
 /*
   delete a record from the database, not updating indexes (used for deleting
   index records)
 */
-int ltdb_delete_noindex(struct ldb_context *ldb, const char *dn)
+int ltdb_delete_noindex(struct ldb_module *module, const struct ldb_dn *dn)
 {
-       struct ltdb_private *ltdb = ldb->private;
+       struct ltdb_private *ltdb = module->private_data;
        TDB_DATA tdb_key;
        int ret;
 
-       tdb_key = ltdb_key(dn);
+       tdb_key = ltdb_key(module, dn);
        if (!tdb_key.dptr) {
-               return -1;
+               return LDB_ERR_OTHER;
        }
 
        ret = tdb_delete(ltdb->tdb, tdb_key);
-       free(tdb_key.dptr);
+       talloc_free(tdb_key.dptr);
+
+       if (ret != 0) {
+               ret = ltdb_err_map(tdb_error(ltdb->tdb));
+       }
 
        return ret;
 }
 
-/*
-  delete a record from the database
-*/
-static int ltdb_delete(struct ldb_context *ldb, const char *dn)
+static int ltdb_delete_internal(struct ldb_module *module, const struct ldb_dn *dn)
 {
+       struct ldb_message *msg;
        int ret;
-       struct ldb_message msg;
+
+       msg = talloc(module, struct ldb_message);
+       if (msg == NULL) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
 
        /* in case any attribute of the message was indexed, we need
           to fetch the old record */
-       ret = ltdb_search_dn1(ldb, dn, &msg);
+       ret = ltdb_search_dn1(module, dn, msg);
        if (ret != 1) {
                /* not finding the old record is an error */
-               return -1;
+               talloc_free(msg);
+               return LDB_ERR_NO_SUCH_OBJECT;
        }
 
-       ret = ltdb_delete_noindex(ldb, dn);
-       if (ret == -1) {
-               ltdb_search_dn1_free(ldb, &msg);
-               return -1;
+       ret = ltdb_delete_noindex(module, dn);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(msg);
+               return LDB_ERR_NO_SUCH_OBJECT;
        }
 
        /* remove any indexed attributes */
-       ret = ltdb_index_del(ldb, &msg);
+       ret = ltdb_index_del(module, msg);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(msg);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       ret = ltdb_modified(module, dn);
+       if (ret != LDB_SUCCESS) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       talloc_free(msg);
+       return LDB_SUCCESS;
+}
+
+/*
+  delete a record from the database
+*/
+static int ltdb_delete(struct ldb_module *module, struct ldb_request *req)
+{
+       struct ltdb_private *ltdb = talloc_get_type(module->private_data, struct ltdb_private);
+       struct ltdb_async_context *ltdb_ac;
+       int tret, ret = LDB_SUCCESS;
 
-       ltdb_search_dn1_free(ldb, &msg);
+       if (req->controls != NULL) {
+               ldb_debug(module->ldb, LDB_DEBUG_WARNING, "Controls should not reach the ldb_tdb backend!\n");
+               if (check_critical_controls(req->controls)) {
+                       return LDB_ERR_UNSUPPORTED_CRITICAL_EXTENSION;
+               }
+       }
+       
+       req->async.handle = NULL;
+
+       if (ltdb_cache_load(module) != 0) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       req->async.handle = init_ltdb_handle(ltdb, module, req->async.context, req->async.callback);
+       if (req->async.handle == NULL) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       ltdb_ac = talloc_get_type(req->async.handle->private_data, struct ltdb_async_context);
 
+       tret = ltdb_delete_internal(module, req->op.del.dn);
+       if (tret != LDB_SUCCESS) {
+               req->async.handle->status = tret; 
+               goto done;
+       }
+
+       if (ltdb_ac->callback) {
+               ret = ltdb_ac->callback(module->ldb, ltdb_ac->context, NULL);
+       }
+done:
+       req->async.handle->state = LDB_ASYNC_DONE;
        return ret;
 }
 
+/*
+  find an element by attribute name. At the moment this does a linear search, it should
+  be re-coded to use a binary search once all places that modify records guarantee
+  sorted order
+
+  return the index of the first matching element if found, otherwise -1
+*/
+static int find_element(const struct ldb_message *msg, const char *name)
+{
+       unsigned int i;
+       for (i=0;i<msg->num_elements;i++) {
+               if (ldb_attr_cmp(msg->elements[i].name, name) == 0) {
+                       return i;
+               }
+       }
+       return -1;
+}
+
 
 /*
-  modify a record
+  add an element to an existing record. Assumes a elements array that we
+  can call re-alloc on, and assumed that we can re-use the data pointers from the 
+  passed in additional values. Use with care!
+
+  returns 0 on success, -1 on failure (and sets errno)
+*/
+static int msg_add_element(struct ldb_context *ldb,
+                          struct ldb_message *msg, struct ldb_message_element *el)
+{
+       struct ldb_message_element *e2;
+       unsigned int i;
+
+       e2 = talloc_realloc(msg, msg->elements, struct ldb_message_element, 
+                             msg->num_elements+1);
+       if (!e2) {
+               errno = ENOMEM;
+               return -1;
+       }
+
+       msg->elements = e2;
+
+       e2 = &msg->elements[msg->num_elements];
+
+       e2->name = el->name;
+       e2->flags = el->flags;
+       e2->values = NULL;
+       if (el->num_values != 0) {
+               e2->values = talloc_array(msg->elements, struct ldb_val, el->num_values);
+               if (!e2->values) {
+                       errno = ENOMEM;
+                       return -1;
+               }
+       }
+       for (i=0;i<el->num_values;i++) {
+               e2->values[i] = el->values[i];
+       }
+       e2->num_values = el->num_values;
+
+       msg->num_elements++;
+
+       return 0;
+}
+
+/*
+  delete all elements having a specified attribute name
 */
-static int ltdb_modify(struct ldb_context *ldb, const struct ldb_message *msg)
+static int msg_delete_attribute(struct ldb_module *module,
+                               struct ldb_context *ldb,
+                               struct ldb_message *msg, const char *name)
 {
-       struct ltdb_private *ltdb = ldb->private;
+       char *dn;
+       unsigned int i, j;
+
+       dn = ldb_dn_linearize(ldb, msg->dn);
+       if (dn == NULL) {
+               return -1;
+       }
+
+       for (i=0;i<msg->num_elements;i++) {
+               if (ldb_attr_cmp(msg->elements[i].name, name) == 0) {
+                       for (j=0;j<msg->elements[i].num_values;j++) {
+                               ltdb_index_del_value(module, dn, &msg->elements[i], j);
+                       }
+                       talloc_free(msg->elements[i].values);
+                       if (msg->num_elements > (i+1)) {
+                               memmove(&msg->elements[i], 
+                                       &msg->elements[i+1], 
+                                       sizeof(struct ldb_message_element)*
+                                       (msg->num_elements - (i+1)));
+                       }
+                       msg->num_elements--;
+                       i--;
+                       msg->elements = talloc_realloc(msg, msg->elements, 
+                                                        struct ldb_message_element, 
+                                                        msg->num_elements);
+               }
+       }
+
+       talloc_free(dn);
+       return 0;
+}
+
+/*
+  delete all elements matching an attribute name/value 
+
+  return 0 on success, -1 on failure
+*/
+static int msg_delete_element(struct ldb_module *module,
+                             struct ldb_message *msg, 
+                             const char *name,
+                             const struct ldb_val *val)
+{
+       struct ldb_context *ldb = module->ldb;
+       unsigned int i;
+       int found;
+       struct ldb_message_element *el;
+       const struct ldb_attrib_handler *h;
+
+       found = find_element(msg, name);
+       if (found == -1) {
+               return -1;
+       }
+
+       el = &msg->elements[found];
+
+       h = ldb_attrib_handler(ldb, el->name);
+
+       for (i=0;i<el->num_values;i++) {
+               if (h->comparison_fn(ldb, ldb, &el->values[i], val) == 0) {
+                       if (i<el->num_values-1) {
+                               memmove(&el->values[i], &el->values[i+1],
+                                       sizeof(el->values[i])*(el->num_values-(i+1)));
+                       }
+                       el->num_values--;
+                       if (el->num_values == 0) {
+                               return msg_delete_attribute(module, ldb, msg, name);
+                       }
+                       return 0;
+               }
+       }
+
+       return -1;
+}
+
+
+/*
+  modify a record - internal interface
+
+  yuck - this is O(n^2). Luckily n is usually small so we probably
+  get away with it, but if we ever have really large attribute lists 
+  then we'll need to look at this again
+*/
+int ltdb_modify_internal(struct ldb_module *module, const struct ldb_message *msg)
+{
+       struct ldb_context *ldb = module->ldb;
+       struct ltdb_private *ltdb = module->private_data;
        TDB_DATA tdb_key, tdb_data;
-       struct ldb_message msg2;
+       struct ldb_message *msg2;
+       unsigned i, j;
        int ret;
 
-       tdb_key = ltdb_key(msg->dn);
+       tdb_key = ltdb_key(module, msg->dn);
        if (!tdb_key.dptr) {
-               return -1;
+               return LDB_ERR_OTHER;
        }
 
        tdb_data = tdb_fetch(ltdb->tdb, tdb_key);
        if (!tdb_data.dptr) {
-               free(tdb_key.dptr);
-               return -1;
+               talloc_free(tdb_key.dptr);
+               return ltdb_err_map(tdb_error(ltdb->tdb));
+       }
+
+       msg2 = talloc(tdb_key.dptr, struct ldb_message);
+       if (msg2 == NULL) {
+               talloc_free(tdb_key.dptr);
+               return LDB_ERR_OTHER;
        }
 
-       ret = ltdb_unpack_data(ldb, &tdb_data, &msg2);
+       ret = ltdb_unpack_data(module, &tdb_data, msg2);
        if (ret == -1) {
-               free(tdb_key.dptr);
-               free(tdb_data.dptr);
-               return -1;
+               ret = LDB_ERR_OTHER;
+               goto failed;
+       }
+
+       if (!msg2->dn) {
+               msg2->dn = msg->dn;
        }
 
-#if 0
        for (i=0;i<msg->num_elements;i++) {
+               struct ldb_message_element *el = &msg->elements[i];
+               struct ldb_message_element *el2;
+               struct ldb_val *vals;
+               char *err_string;
+               char *dn;
+
                switch (msg->elements[i].flags & LDB_FLAG_MOD_MASK) {
+
                case LDB_FLAG_MOD_ADD:
-                       ret = find_element(&msg2, msg->elements[i].name);
-                       if (ret != -1) {
-                               errno = EEXIST;
+                       /* add this element to the message. fail if it
+                          already exists */
+                       ret = find_element(msg2, el->name);
+
+                       if (ret == -1) {
+                               if (msg_add_element(ldb, msg2, el) != 0) {
+                                       ret = LDB_ERR_OTHER;
+                                       goto failed;
+                               }
+                               continue;
+                       }
+
+                       el2 = &msg2->elements[ret];
+
+                       /* An attribute with this name already exists, add all
+                        * values if they don't already exist. */
+
+                       for (j=0;j<el->num_values;j++) {
+                               if (ldb_msg_find_val(el2, &el->values[j])) {
+                                       err_string = talloc_strdup(module, "Type or value exists");
+                                       if (err_string) ldb_set_errstring(module->ldb, err_string);
+                                       ret = LDB_ERR_ATTRIBUTE_OR_VALUE_EXISTS;
+                                       goto failed;
+                               }
+                       }
+
+                       vals = talloc_realloc(msg2->elements, el2->values, struct ldb_val,
+                                               el2->num_values + el->num_values);
+
+                       if (vals == NULL) {
+                               ret = LDB_ERR_OTHER;
+                               goto failed;
+                       }
+
+                       for (j=0;j<el->num_values;j++) {
+                               vals[el2->num_values + j] =
+                                       ldb_val_dup(vals, &el->values[j]);
+                       }
+
+                       el2->values = vals;
+                       el2->num_values += el->num_values;
+
+                       break;
+
+               case LDB_FLAG_MOD_REPLACE:
+                       /* replace all elements of this attribute name with the elements
+                          listed. The attribute not existing is not an error */
+                       msg_delete_attribute(module, ldb, msg2, msg->elements[i].name);
+
+                       /* add the replacement element, if not empty */
+                       if (msg->elements[i].num_values != 0 &&
+                           msg_add_element(ldb, msg2, &msg->elements[i]) != 0) {
+                               ret = LDB_ERR_OTHER;
                                goto failed;
                        }
-                       
+                       break;
+
+               case LDB_FLAG_MOD_DELETE:
+
+                       dn = ldb_dn_linearize(msg2, msg->dn);
+                       if (dn == NULL) {
+                               ret = LDB_ERR_OTHER;
+                               goto failed;
+                       }
+
+                       /* we could be being asked to delete all
+                          values or just some values */
+                       if (msg->elements[i].num_values == 0) {
+                               if (msg_delete_attribute(module, ldb, msg2, 
+                                                        msg->elements[i].name) != 0) {
+                                       err_string = talloc_asprintf(module, "No such attribute: %s", msg->elements[i].name);
+                                       if (err_string) ldb_set_errstring(module->ldb, err_string);
+                                       ret = LDB_ERR_NO_SUCH_ATTRIBUTE;
+                                       goto failed;
+                               }
+                               break;
+                       }
+                       for (j=0;j<msg->elements[i].num_values;j++) {
+                               if (msg_delete_element(module,
+                                                      msg2, 
+                                                      msg->elements[i].name,
+                                                      &msg->elements[i].values[j]) != 0) {
+                                       err_string = talloc_asprintf(module, "No such attribute: %s", msg->elements[i].name);
+                                       if (err_string) ldb_set_errstring(module->ldb, err_string);
+                                       ret = LDB_ERR_NO_SUCH_ATTRIBUTE;
+                                       goto failed;
+                               }
+                               if (ltdb_index_del_value(module, dn, &msg->elements[i], j) != 0) {
+                                       ret = LDB_ERR_OTHER;
+                                       goto failed;
+                               }
+                       }
+                       break;
+               default:
+                       err_string = talloc_asprintf(module, "Invalid ldb_modify flags on %s: 0x%x", 
+                                                    msg->elements[i].name, 
+                                                    msg->elements[i].flags & LDB_FLAG_MOD_MASK);
+                       if (err_string) ldb_set_errstring(module->ldb, err_string);
+                       ret = LDB_ERR_PROTOCOL_ERROR;
+                       goto failed;
                }
        }
 
-failed:
-#endif
+       /* we've made all the mods - save the modified record back into the database */
+       ret = ltdb_store(module, msg2, TDB_MODIFY);
+       if (ret != LDB_SUCCESS) {
+               goto failed;
+       }
+
+       if (ltdb_modified(module, msg->dn) != LDB_SUCCESS) {
+               ret = LDB_ERR_OPERATIONS_ERROR;
+               goto failed;
+       }
 
-       free(tdb_key.dptr);
+       talloc_free(tdb_key.dptr);
        free(tdb_data.dptr);
-       if (msg2.elements) free(msg2.elements);
-       
-       return -1;
+       return ret;
+
+failed:
+       talloc_free(tdb_key.dptr);
+       free(tdb_data.dptr);
+       return ret;
 }
 
 /*
-  close database
+  modify a record
 */
-static int ltdb_close(struct ldb_context *ldb)
+static int ltdb_modify(struct ldb_module *module, struct ldb_request *req)
 {
-       struct ltdb_private *ltdb = ldb->private;
-       int ret;
-       ret = tdb_close(ltdb->tdb);
-       free(ltdb);
-       free(ldb);
+       struct ltdb_private *ltdb = talloc_get_type(module->private_data, struct ltdb_private);
+       struct ltdb_async_context *ltdb_ac;
+       int tret, ret = LDB_SUCCESS;
+
+       if (req->controls != NULL) {
+               ldb_debug(module->ldb, LDB_DEBUG_WARNING, "Controls should not reach the ldb_tdb backend!\n");
+               if (check_critical_controls(req->controls)) {
+                       return LDB_ERR_UNSUPPORTED_CRITICAL_EXTENSION;
+               }
+       }
+       
+       req->async.handle = NULL;
+
+       req->async.handle = init_ltdb_handle(ltdb, module, req->async.context, req->async.callback);
+       if (req->async.handle == NULL) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       ltdb_ac = talloc_get_type(req->async.handle->private_data, struct ltdb_async_context);
+
+       tret = ltdb_check_special_dn(module, req->op.mod.message);
+       if (tret != LDB_SUCCESS) {
+               req->async.handle->status = tret;
+               goto done;
+       }
+       
+       if (ltdb_cache_load(module) != 0) {
+               ret = LDB_ERR_OPERATIONS_ERROR;
+               goto done;
+       }
+
+       tret = ltdb_modify_internal(module, req->op.mod.message);
+       if (tret != LDB_SUCCESS) {
+               req->async.handle->status = tret;
+               goto done;
+       }
+
+       if (ltdb_ac->callback) {
+               ret = ltdb_ac->callback(module->ldb, ltdb_ac->context, NULL);
+       }
+done:
+       req->async.handle->state = LDB_ASYNC_DONE;
        return ret;
 }
-                     
 
 /*
-  return extended error information
+  rename a record
 */
-static const char *ltdb_errstring(struct ldb_context *ldb)
+static int ltdb_rename(struct ldb_module *module, struct ldb_request *req)
+{
+       struct ltdb_private *ltdb = talloc_get_type(module->private_data, struct ltdb_private);
+       struct ltdb_async_context *ltdb_ac;
+       struct ldb_message *msg;
+       int tret, ret = LDB_SUCCESS;
+
+       if (req->controls != NULL) {
+               ldb_debug(module->ldb, LDB_DEBUG_WARNING, "Controls should not reach the ldb_tdb backend!\n");
+               if (check_critical_controls(req->controls)) {
+                       return LDB_ERR_UNSUPPORTED_CRITICAL_EXTENSION;
+               }
+       }
+       
+       req->async.handle = NULL;
+
+       if (ltdb_cache_load(module) != 0) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       req->async.handle = init_ltdb_handle(ltdb, module, req->async.context, req->async.callback);
+       if (req->async.handle == NULL) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       ltdb_ac = talloc_get_type(req->async.handle->private_data, struct ltdb_async_context);
+
+       msg = talloc(ltdb_ac, struct ldb_message);
+       if (msg == NULL) {
+               ret = LDB_ERR_OPERATIONS_ERROR;
+               goto done;
+       }
+
+       /* in case any attribute of the message was indexed, we need
+          to fetch the old record */
+       tret = ltdb_search_dn1(module, req->op.rename.olddn, msg);
+       if (tret != 1) {
+               /* not finding the old record is an error */
+               req->async.handle->status = LDB_ERR_NO_SUCH_OBJECT;
+               goto done;
+       }
+
+       msg->dn = ldb_dn_copy(msg, req->op.rename.newdn);
+       if (!msg->dn) {
+               ret = LDB_ERR_OPERATIONS_ERROR;
+               goto done;
+       }
+
+       tret = ltdb_add_internal(module, msg);
+       if (tret != LDB_SUCCESS) {
+               ret = LDB_ERR_OPERATIONS_ERROR;
+               goto done;
+       }
+
+       tret = ltdb_delete_internal(module, req->op.rename.olddn);
+       if (tret != LDB_SUCCESS) {
+               ltdb_delete_internal(module, req->op.rename.newdn);
+               ret = LDB_ERR_OPERATIONS_ERROR;
+               goto done;
+       }
+
+       if (ltdb_ac->callback) {
+               ret = ltdb_ac->callback(module->ldb, ltdb_ac->context, NULL);
+       }
+done:
+       req->async.handle->state = LDB_ASYNC_DONE;
+       return ret;
+}
+
+static int ltdb_start_trans(struct ldb_module *module)
 {
-       struct ltdb_private *ltdb = ldb->private;
-       return tdb_errorstr(ltdb->tdb);
+       struct ltdb_private *ltdb = module->private_data;
+
+       if (tdb_transaction_start(ltdb->tdb) != 0) {
+               return ltdb_err_map(tdb_error(ltdb->tdb));
+       }
+
+       return LDB_SUCCESS;
 }
 
+static int ltdb_end_trans(struct ldb_module *module)
+{
+       struct ltdb_private *ltdb = module->private_data;
 
-static const struct ldb_backend_ops ltdb_ops = {
-       ltdb_close, 
-       ltdb_search,
-       ltdb_search_free,
-       ltdb_add,
-       ltdb_modify,
-       ltdb_delete,
-       ltdb_errstring
-};
+       if (tdb_transaction_commit(ltdb->tdb) != 0) {
+               return ltdb_err_map(tdb_error(ltdb->tdb));
+       }
+
+       return LDB_SUCCESS;
+}
+
+static int ltdb_del_trans(struct ldb_module *module)
+{
+       struct ltdb_private *ltdb = module->private_data;
+
+       if (tdb_transaction_cancel(ltdb->tdb) != 0) {
+               return ltdb_err_map(tdb_error(ltdb->tdb));
+       }
+
+       return LDB_SUCCESS;
+}
+
+static int ltdb_async_wait(struct ldb_async_handle *handle, enum ldb_async_wait_type type)
+{
+       return handle->status;
+}
+
+static int ltdb_request(struct ldb_module *module, struct ldb_request *req)
+{
+       /* check for oustanding critical controls and return an error if found */
+       if (req->controls != NULL) {
+               ldb_debug(module->ldb, LDB_DEBUG_WARNING, "Controls should not reach the ldb_tdb backend!\n");
+               if (check_critical_controls(req->controls)) {
+                       return LDB_ERR_UNSUPPORTED_CRITICAL_EXTENSION;
+               }
+       }
+       
+       /* search, add, modify, delete, rename are handled by their own, no other op supported */
+       return LDB_ERR_OPERATIONS_ERROR;
+}
+
+/*
+  return sequenceNumber from @BASEINFO
+*/
+static int ltdb_sequence_number(struct ldb_module *module, struct ldb_request *req)
+{
+       TALLOC_CTX *tmp_ctx = talloc_new(req);
+       struct ldb_message *msg = NULL;
+       struct ldb_dn *dn = ldb_dn_explode(tmp_ctx, "@BASEINFO");
+       int tret;
+
+       if (tmp_ctx == NULL) {
+               talloc_free(tmp_ctx);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       msg = talloc(tmp_ctx, struct ldb_message);
+       if (msg == NULL) {
+               talloc_free(tmp_ctx);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       tret = ltdb_search_dn1(module, dn, msg);
+       if (tret != 1) {
+               talloc_free(tmp_ctx);
+               req->op.seq_num.seq_num = 0;
+               /* zero is as good as anything when we don't know */
+               return LDB_SUCCESS;
+       }
+
+       req->op.seq_num.seq_num = ldb_msg_find_uint64(msg, "sequenceNumber", 0);
+       talloc_free(tmp_ctx);
+       return LDB_SUCCESS;
+}
 
+static const struct ldb_module_ops ltdb_ops = {
+       .name              = "tdb",
+       .search            = ltdb_search,
+       .add               = ltdb_add,
+       .modify            = ltdb_modify,
+       .del               = ltdb_delete,
+       .rename            = ltdb_rename,
+       .request           = ltdb_request,
+       .start_transaction = ltdb_start_trans,
+       .end_transaction   = ltdb_end_trans,
+       .del_transaction   = ltdb_del_trans,
+       .async_wait        = ltdb_async_wait,
+       .sequence_number   = ltdb_sequence_number
+};
 
 /*
   connect to the database
 */
-struct ldb_context *ltdb_connect(const char *url, 
-                                unsigned int flags, 
-                                const char *options[])
+static int ltdb_connect(struct ldb_context *ldb, const char *url, 
+                       unsigned int flags, const char *options[],
+                       struct ldb_module **module)
 {
        const char *path;
        int tdb_flags, open_flags;
        struct ltdb_private *ltdb;
-       TDB_CONTEXT *tdb;
-       struct ldb_context *ldb;
 
        /* parse the url */
-       if (strncmp(url, "tdb://", 6) != 0) {
-               errno = EINVAL;
-               return NULL;
+       if (strchr(url, ':')) {
+               if (strncmp(url, "tdb://", 6) != 0) {
+                       ldb_debug(ldb, LDB_DEBUG_ERROR, "Invalid tdb URL '%s'", url);
+                       return -1;
+               }
+               path = url+6;
+       } else {
+               path = url;
        }
 
-       path = url+6;
-
        tdb_flags = TDB_DEFAULT;
 
+       /* check for the 'nosync' option */
+       if (flags & LDB_FLG_NOSYNC) {
+               tdb_flags |= TDB_NOSYNC;
+       }
+
        if (flags & LDB_FLG_RDONLY) {
                open_flags = O_RDONLY;
        } else {
                open_flags = O_CREAT | O_RDWR;
        }
 
-       tdb = tdb_open(path, 0, tdb_flags, open_flags, 0666);
-       if (!tdb) {
-               return NULL;
+       ltdb = talloc_zero(ldb, struct ltdb_private);
+       if (!ltdb) {
+               ldb_oom(ldb);
+               return -1;
        }
 
-       ltdb = malloc_p(struct ltdb_private);
-       if (!ltdb) {
-               tdb_close(tdb);
-               errno = ENOMEM;
-               return NULL;
+       /* note that we use quite a large default hash size */
+       ltdb->tdb = ltdb_wrap_open(ltdb, path, 10000, 
+                                  tdb_flags, open_flags, 0666, ldb);
+       if (!ltdb->tdb) {
+               ldb_debug(ldb, LDB_DEBUG_ERROR, "Unable to open tdb '%s'\n", path);
+               talloc_free(ltdb);
+               return -1;
        }
 
-       ltdb->tdb = tdb;
-       
+       ltdb->sequence_number = 0;
 
-       ldb = malloc_p(struct ldb_context);
-       if (!ldb) {
-               tdb_close(tdb);
-               free(ltdb);
-               errno = ENOMEM;
-               return NULL;
+       *module = talloc(ldb, struct ldb_module);
+       if (!module) {
+               ldb_oom(ldb);
+               talloc_free(ltdb);
+               return -1;
        }
+       (*module)->ldb = ldb;
+       (*module)->prev = (*module)->next = NULL;
+       (*module)->private_data = ltdb;
+       (*module)->ops = &ltdb_ops;
 
-       ldb->private = ltdb;
-       ldb->ops = &ltdb_ops;
+       return 0;
+}
 
-       return ldb;
+int ldb_tdb_init(void)
+{
+       return ldb_register_backend("tdb", ltdb_connect);
 }