1 files changed, 557 insertions, 0 deletions

diff --git a/ldb/modules/paged_results.c b/ldb/modules/paged_results.c
new file mode 100644
index 000000000..b62b1f92c
--- /dev/null
+++ b/ldb/modules/paged_results.c
@@ -0,0 +1,557 @@
+/* 
+   ldb database library
+
+   Copyright (C) Simo Sorce  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: paged_result
+ *
+ *  Component: ldb paged results control module
+ *
+ *  Description: this module caches a complete search and sends back
+ *  		 results in chunks as asked by the client
+ *
+ *  Author: Simo Sorce
+ */
+
+#include "ldb_includes.h"
+
+struct message_store {
+	/* keep the whole ldb_reply as an optimization
+	 * instead of freeing and talloc-ing the container
+	 * on each result */
+	struct ldb_reply *r;
+	struct message_store *next;
+};
+
+struct private_data;
+
+struct results_store {
+
+	struct private_data *priv;
+
+	char *cookie;
+	time_t timestamp;
+
+	struct results_store *prev;
+	struct results_store *next;
+	
+	struct message_store *first;
+	struct message_store *last;
+	int num_entries;
+
+	struct message_store *first_ref;
+	struct message_store *last_ref;
+
+	struct ldb_control **controls;
+
+	struct ldb_request *req;
+};
+
+struct private_data {
+
+	int next_free_id;
+	struct results_store *store;
+	
+};
+
+int store_destructor(struct results_store *store)
+{
+	if (store->prev) {
+		store->prev->next = store->next;
+	}
+	if (store->next) {
+		store->next->prev = store->prev;
+	}
+
+	if (store == store->priv->store) {
+		store->priv->store = NULL;
+	}
+
+	return 0;
+}
+
+static struct results_store *new_store(struct private_data *priv)
+{
+	struct results_store *newr;
+	int new_id = priv->next_free_id++;
+
+	/* TODO: we should have a limit on the number of
+	 * outstanding paged searches
+	 */
+
+	newr = talloc(priv, struct results_store);
+	if (!newr) return NULL;
+
+	newr->priv = priv;
+
+	newr->cookie = talloc_asprintf(newr, "%d", new_id);
+	if (!newr->cookie) {
+		talloc_free(newr);
+		return NULL;
+	}
+
+	newr->timestamp = time(NULL);
+
+	newr->first = NULL;
+	newr->num_entries = 0;
+	newr->first_ref = NULL;
+	newr->controls = NULL;
+
+	/* put this entry as first */
+	newr->prev = NULL;
+	newr->next = priv->store;
+	if (priv->store != NULL) priv->store->prev = newr;
+	priv->store = newr;
+
+	talloc_set_destructor(newr, store_destructor);
+
+	return newr;
+}
+
+struct paged_context {
+	struct ldb_module *module;
+	void *up_context;
+	int (*up_callback)(struct ldb_context *, void *, struct ldb_reply *);
+
+	int size;
+
+	struct results_store *store;
+};
+
+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 paged_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 paged_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 paged_search_callback(struct ldb_context *ldb, void *context, struct ldb_reply *ares)
+{
+	struct paged_context *ac = NULL;
+
+	if (!context || !ares) {
+		ldb_set_errstring(ldb, "NULL Context or Result in callback");
+		goto error;
+	}
+
+	ac = talloc_get_type(context, struct paged_context);
+
+	if (ares->type == LDB_REPLY_ENTRY) {
+		if (ac->store->first == NULL) {
+			ac->store->first = ac->store->last = talloc(ac->store, struct message_store);
+		} else {
+			ac->store->last->next = talloc(ac->store, struct message_store);
+			ac->store->last = ac->store->last->next;
+		}
+		if (ac->store->last == NULL) {
+			goto error;
+		}
+
+		ac->store->num_entries++;
+
+		ac->store->last->r = talloc_steal(ac->store->last, ares);
+		ac->store->last->next = NULL;
+	}
+
+	if (ares->type == LDB_REPLY_REFERRAL) {
+		if (ac->store->first_ref == NULL) {
+			ac->store->first_ref = ac->store->last_ref = talloc(ac->store, struct message_store);
+		} else {
+			ac->store->last_ref->next = talloc(ac->store, struct message_store);
+			ac->store->last_ref = ac->store->last_ref->next;
+		}
+		if (ac->store->last_ref == NULL) {
+			goto error;
+		}
+
+		ac->store->last_ref->r = talloc_steal(ac->store->last, ares);
+		ac->store->last_ref->next = NULL;
+	}
+
+	if (ares->type == LDB_REPLY_DONE) {
+		ac->store->controls = talloc_move(ac->store, &ares->controls);
+		talloc_free(ares);
+	}
+
+	return LDB_SUCCESS;
+
+error:
+	talloc_free(ares);
+	return LDB_ERR_OPERATIONS_ERROR;
+}
+
+static int paged_search(struct ldb_module *module, struct ldb_request *req)
+{
+	struct ldb_control *control;
+	struct private_data *private_data;
+	struct ldb_paged_control *paged_ctrl;
+	struct ldb_control **saved_controls;
+	struct paged_context *ac;
+	struct ldb_handle *h;
+	int ret;
+
+	/* check if there's a paged request control */
+	control = ldb_request_get_control(req, LDB_CONTROL_PAGED_RESULTS_OID);
+	if (control == NULL) {
+		/* not found go on */
+		return ldb_next_request(module, req);
+	}
+
+	private_data = talloc_get_type(module->private_data, struct private_data);
+
+	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;
+	}
+	
+	paged_ctrl = talloc_get_type(control->data, struct ldb_paged_control);
+	if (!paged_ctrl) {
+		return LDB_ERR_PROTOCOL_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 paged_context);
+
+	ac->size = paged_ctrl->size;
+
+	/* check if it is a continuation search the store */
+	if (paged_ctrl->cookie_len == 0) {
+		
+		ac->store = new_store(private_data);
+		if (ac->store == NULL) {
+			talloc_free(h);
+			return LDB_ERR_UNWILLING_TO_PERFORM;
+		}
+
+		ac->store->req = talloc(ac->store, struct ldb_request);
+		if (!ac->store->req)
+			return LDB_ERR_OPERATIONS_ERROR;
+
+		ac->store->req->operation = req->operation;
+		ac->store->req->op.search.base = req->op.search.base;
+		ac->store->req->op.search.scope = req->op.search.scope;
+		ac->store->req->op.search.tree = req->op.search.tree;
+		ac->store->req->op.search.attrs = req->op.search.attrs;
+		ac->store->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->store->req, &saved_controls)) {
+			return LDB_ERR_OPERATIONS_ERROR;
+		}
+
+		ac->store->req->context = ac;
+		ac->store->req->callback = paged_search_callback;
+		ldb_set_timeout_from_prev_req(module->ldb, req, ac->store->req);
+
+		ret = ldb_next_request(module, ac->store->req);
+
+	} else {
+		struct results_store *current = NULL;
+
+		for (current = private_data->store; current; current = current->next) {
+			if (strcmp(current->cookie, paged_ctrl->cookie) == 0) {
+				current->timestamp = time(NULL);
+				break;
+			}
+		}
+		if (current == NULL) {
+			talloc_free(h);
+			return LDB_ERR_UNWILLING_TO_PERFORM;
+		}
+
+		ac->store = current;
+		ret = LDB_SUCCESS;
+	}
+
+	req->handle = h;
+
+	/* check if it is an abandon */
+	if (ac->size == 0) {
+		talloc_free(ac->store);
+		h->status = LDB_SUCCESS;
+		h->state = LDB_ASYNC_DONE;
+		return LDB_SUCCESS;
+	}
+
+	/* TODO: age out old outstanding requests */
+
+	return ret;
+
+}
+
+static int paged_results(struct ldb_handle *handle)
+{
+	struct paged_context *ac;
+	struct ldb_paged_control *paged;
+	struct ldb_reply *ares;
+	struct message_store *msg;
+	int i, num_ctrls, ret;
+
+	ac = talloc_get_type(handle->private_data, struct paged_context);
+
+	if (ac->store == NULL)
+		return LDB_ERR_OPERATIONS_ERROR;
+
+	while (ac->store->num_entries > 0 && ac->size > 0) {
+		msg = ac->store->first;
+		ret = ac->up_callback(ac->module->ldb, ac->up_context, msg->r);
+		if (ret != LDB_SUCCESS) {
+			handle->status = ret;
+			handle->state = LDB_ASYNC_DONE;
+			return ret;
+		}
+
+		ac->store->first = msg->next;
+		talloc_free(msg);
+		ac->store->num_entries--;
+		ac->size--;
+	}
+
+	handle->state = LDB_ASYNC_DONE;
+
+	while (ac->store->first_ref != NULL) {
+		msg = ac->store->first_ref;
+		ret = ac->up_callback(ac->module->ldb, ac->up_context, msg->r);
+		if (ret != LDB_SUCCESS) {
+			handle->status = ret;
+			handle->state = LDB_ASYNC_DONE;
+			return ret;
+		}
+
+		ac->store->first_ref = msg->next;
+		talloc_free(msg);
+	}
+
+	ares = talloc_zero(ac->store, struct ldb_reply);
+	if (ares == NULL) {
+		handle->status = LDB_ERR_OPERATIONS_ERROR;
+		return handle->status;
+	}
+	num_ctrls = 2;
+	i = 0;
+
+	if (ac->store->controls != NULL) {
+		ares->controls = ac->store->controls;
+		while (ares->controls[i]) i++; /* counting */
+
+		ares->controls = talloc_move(ares, &ac->store->controls);
+		num_ctrls += i;
+	}
+
+	ares->controls = talloc_realloc(ares, ares->controls, struct ldb_control *, num_ctrls);
+	if (ares->controls == NULL) {
+		handle->status = LDB_ERR_OPERATIONS_ERROR;
+		return handle->status;
+	}
+
+	ares->controls[i] = talloc(ares->controls, struct ldb_control);
+	if (ares->controls[i] == NULL) {
+		handle->status = LDB_ERR_OPERATIONS_ERROR;
+		return handle->status;
+	}
+
+	ares->controls[i]->oid = talloc_strdup(ares->controls[i], LDB_CONTROL_PAGED_RESULTS_OID);
+	if (ares->controls[i]->oid == NULL) {
+		handle->status = LDB_ERR_OPERATIONS_ERROR;
+		return handle->status;
+	}
+		
+	ares->controls[i]->critical = 0;
+	ares->controls[i + 1] = NULL;
+
+	paged = talloc(ares->controls[i], struct ldb_paged_control);
+	if (paged == NULL) {
+		handle->status = LDB_ERR_OPERATIONS_ERROR;
+		return handle->status;
+	}
+	
+	ares->controls[i]->data = paged;
+
+	if (ac->size > 0) {
+		paged->size = 0;
+		paged->cookie = NULL;
+		paged->cookie_len = 0;
+	} else {
+		paged->size = ac->store->num_entries;
+		paged->cookie = talloc_strdup(paged, ac->store->cookie);
+		paged->cookie_len = strlen(paged->cookie) + 1;
+	}
+
+	ares->type = LDB_REPLY_DONE;
+
+	ret = ac->up_callback(ac->module->ldb, ac->up_context, ares);
+
+	handle->status = ret;
+
+	return ret;
+}
+
+static int paged_wait_once(struct ldb_handle *handle) {
+	struct paged_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;
+
+	ac = talloc_get_type(handle->private_data, struct paged_context);
+
+	if (ac->store->req->handle->state == LDB_ASYNC_DONE) {
+		/* if lower level is finished we do not need to call it anymore */
+		/* return all we have until size == 0 or we empty storage */
+		ret = paged_results(handle);
+
+		/* we are done, if num_entries is zero free the storage
+		 * as that mean we delivered the last batch */
+		if (ac->store->num_entries == 0) {
+			talloc_free(ac->store);
+		}
+
+		return ret;
+	}
+
+	ret = ldb_wait(ac->store->req->handle, LDB_WAIT_NONE);
+	if (ret != LDB_SUCCESS) {
+		handle->state = LDB_ASYNC_DONE;
+		handle->status = ret;
+		return ret;
+	}
+
+	handle->status = ret;
+
+	if (ac->store->num_entries >= ac->size ||
+	    ac->store->req->handle->state == LDB_ASYNC_DONE) {
+
+		ret = paged_results(handle);
+
+		/* we are done, if num_entries is zero free the storage
+		 * as that mean we delivered the last batch */
+		if (ac->store->num_entries == 0) {
+			talloc_free(ac->store);
+		}
+	}
+
+	return ret;
+}
+
+static int paged_wait(struct ldb_handle *handle, enum ldb_wait_type type)
+{
+	int ret;
+ 
+	if (!handle || !handle->private_data) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	if (type == LDB_WAIT_ALL) {
+		while (handle->state != LDB_ASYNC_DONE) {
+			ret = paged_wait_once(handle);
+			if (ret != LDB_SUCCESS) {
+				return ret;
+			}
+		}
+
+		return handle->status;
+	}
+
+	return paged_wait_once(handle);
+}
+
+static int paged_request_init(struct ldb_module *module)
+{
+	struct private_data *data;
+	struct ldb_request *req;
+	int ret;
+
+	data = talloc(module, struct private_data);
+	if (data == NULL) {
+		return LDB_ERR_OTHER;
+	}
+	
+	data->next_free_id = 1;
+	data->store = NULL;
+	module->private_data = data;
+
+	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_PAGED_RESULTS_OID;
+	req->controls = NULL;
+
+	ret = ldb_request(module->ldb, req);
+	if (ret != LDB_SUCCESS) {
+		ldb_debug(module->ldb, LDB_DEBUG_WARNING, "paged_request: Unable to register control with rootdse!\n");
+	}
+
+	talloc_free(req);
+	return ldb_next_init(module);
+}
+
+const struct ldb_module_ops ldb_paged_results_module_ops = {
+	.name           = "paged_results",
+	.search         = paged_search,
+	.wait           = paged_wait,
+	.init_context 	= paged_request_init
+};