r17614: Our first "client side' ldb module.

This module has been created with the purpose of being used
for searches against ldap servers without the need to handle
the control manually

You can test it by passing -o modules:paged_searches to ldbsearch

The page search size is set to 500 objects.

Simo.
(This used to be commit 07d377f3c27966b40465bb5dc4f55746ba8489af)

2 files changed, 448 insertions, 0 deletions

diff --git a/source4/lib/ldb/config.mk b/source4/lib/ldb/config.mk
index d52ec4cf06..dfbf3db449 100644
--- a/source4/lib/ldb/config.mk
+++ b/source4/lib/ldb/config.mk
@@ -29,6 +29,16 @@ OBJ_FILES = \
 ################################################
 
 ################################################
+# Start MODULE ldb_paged_results
+[MODULE::ldb_paged_searches]
+INIT_FUNCTION = ldb_paged_searches_init
+SUBSYSTEM = ldb
+OBJ_FILES = \
+		modules/paged_searches.o
+# End MODULE ldb_paged_results
+################################################
+
+################################################
 # Start MODULE ldb_operational
 [MODULE::ldb_operational]
 SUBSYSTEM = ldb
diff --git a/source4/lib/ldb/modules/paged_searches.c b/source4/lib/ldb/modules/paged_searches.c
new file mode 100644
index 0000000000..a867aab01c
--- /dev/null
+++ b/source4/lib/ldb/modules/paged_searches.c
@@ -0,0 +1,438 @@
+/* 
+   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 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: paged_searches
+ *
+ *  Component: ldb paged searches module
+ *
+ *  Description: this module detects if the remote ldap server supports
+ *               paged results and use them to transparently access all objects
+ *
+ *  Author: Simo Sorce
+ */
+
+#include "includes.h"
+#include "ldb/include/includes.h"
+
+#define PS_DEFAULT_PAGE_SIZE 500
+/* 500 objects per query seem to be a decent compromise
+ * the default AD limit per request is 1000 entries */
+
+struct private_data {
+
+	bool paged_supported;
+};
+
+struct ps_context {
+	struct ldb_module *module;
+	void *up_context;
+	int (*up_callback)(struct ldb_context *, void *, struct ldb_reply *);
+
+	struct ldb_request *orig_req;
+
+	struct ldb_request *new_req;
+
+	bool pending;
+
+	char **saved_referrals;
+	int num_referrals;
+};
+
+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 ps_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 ps_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;
+
+	ac->pending = False;
+	ac->saved_referrals = NULL;
+	ac->num_referrals = 0;
+
+	return h;
+}
+
+static bool check_ps_continuation(struct ldb_reply *ares, struct ps_context *ac)
+{
+	struct ldb_paged_control *rep_control, *req_control;
+
+	/* look up our paged control */
+	if (strcmp(LDB_CONTROL_PAGED_RESULTS_OID, ares->controls[0]->oid) != 0) {
+		/* something wrong here */
+		return False;
+	}
+
+	rep_control = talloc_get_type(ares->controls[0]->data, struct ldb_paged_control);
+	if (rep_control->cookie_len == 0) {
+		/* we are done */
+		ac->pending = False;
+		return True;
+	}
+
+	/* more processing required */
+	/* let's fill in the request control with the new cookie */
+	/* if there's a reply control we must find a request
+	 * control matching it */
+
+	if (strcmp(LDB_CONTROL_PAGED_RESULTS_OID, ac->new_req->controls[0]->oid) != 0) {
+		/* something wrong here */
+		return False;
+	}
+
+	req_control = talloc_get_type(ac->new_req->controls[0]->data, struct ldb_paged_control);
+
+	if (req_control->cookie) {
+		talloc_free(req_control->cookie);
+	}
+
+	req_control->cookie = talloc_memdup(req_control,
+					    rep_control->cookie,
+					    rep_control->cookie_len);
+	req_control->cookie_len = rep_control->cookie_len;
+
+	ac->pending = True;
+	return True;
+}
+
+static int store_referral(char *referral, struct ps_context *ac)
+{
+	ac->saved_referrals = talloc_realloc(ac, ac->saved_referrals, char *, ac->num_referrals + 2);
+	if (!ac->saved_referrals) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	ac->saved_referrals[ac->num_referrals] = talloc_strdup(ac->saved_referrals, referral);
+	if (!ac->saved_referrals[ac->num_referrals]) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	ac->num_referrals++;
+	ac->saved_referrals[ac->num_referrals] = NULL;
+
+	return LDB_SUCCESS;
+}
+
+static int send_referrals(struct ldb_context *ldb, struct ps_context *ac)
+{
+	struct ldb_reply *ares;
+	int i;
+
+	for (i = 0; i < ac->num_referrals; i++) {
+		ares = talloc_zero(ac, struct ldb_reply);
+		if (!ares) {
+			return LDB_ERR_OPERATIONS_ERROR;
+		}
+
+		ares->type = LDB_REPLY_REFERRAL;
+		ares->referral = ac->saved_referrals[i];
+
+		ac->up_callback(ldb, ac->up_context, ares);
+	}
+
+	return LDB_SUCCESS;
+}
+
+static int ps_callback(struct ldb_context *ldb, void *context, struct ldb_reply *ares)
+{
+	struct ps_context *ac = NULL;
+	int ret;
+
+	if (!context || !ares) {
+		ldb_set_errstring(ldb, "NULL Context or Result in callback");
+		goto error;
+	}
+
+	ac = talloc_get_type(context, struct ps_context);
+
+	switch (ares->type) {
+	case LDB_REPLY_ENTRY:
+		ac->up_callback(ldb, ac->up_context, ares);
+		break;
+
+	case LDB_REPLY_REFERRAL:
+		ret = store_referral(ares->referral, ac);
+		if (ret != LDB_SUCCESS) {
+			goto error;
+		}
+		break;
+
+	case LDB_REPLY_DONE:
+		if (!check_ps_continuation(ares, ac)) {
+			goto error;
+		}
+		if (!ac->pending) {
+			/* send referrals */
+			ret = send_referrals(ldb, ac);
+			if (ret != LDB_SUCCESS) {
+				goto error;
+			}
+
+			/* send REPLY_DONE */
+			ac->up_callback(ldb, ac->up_context, ares);
+		}
+		break;
+	default:
+		goto error;
+	}
+
+	return LDB_SUCCESS;
+
+error:
+	talloc_free(ares);
+	return LDB_ERR_OPERATIONS_ERROR;
+}
+
+static int ps_search(struct ldb_module *module, struct ldb_request *req)
+{
+	struct private_data *private_data;
+	struct ldb_paged_control *control;
+	struct ps_context *ac;
+	struct ldb_handle *h;
+
+	private_data = talloc_get_type(module->private_data, struct private_data);
+
+	/* check if paging is supported and if there is a any control */
+	if (!private_data->paged_supported || req->controls) {
+		/* do not touch this request
+		 * oaged controls not supported or
+		 * explicit controls have been set */
+		return ldb_next_request(module, req);
+	}
+
+	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 ps_context);
+
+	ac->new_req = talloc(ac, struct ldb_request);
+	if (!ac->new_req) return LDB_ERR_OPERATIONS_ERROR;
+
+	ac->new_req->controls = talloc_array(ac->new_req, struct ldb_control *, 2);
+	if (!ac->new_req->controls) return LDB_ERR_OPERATIONS_ERROR;
+
+	ac->new_req->controls[0] = talloc(ac->new_req->controls, struct ldb_control);
+	if (!ac->new_req->controls[0]) return LDB_ERR_OPERATIONS_ERROR;
+
+	control = talloc(ac->new_req->controls[0], struct ldb_paged_control);
+	if (!control) return LDB_ERR_OPERATIONS_ERROR;
+
+	control->size = PS_DEFAULT_PAGE_SIZE;
+	control->cookie = NULL;
+	control->cookie_len = 0;
+
+	ac->new_req->controls[0]->oid = LDB_CONTROL_PAGED_RESULTS_OID;
+	ac->new_req->controls[0]->critical = 1;
+	ac->new_req->controls[0]->data = control;
+
+	ac->new_req->controls[1] = NULL;
+
+	ac->new_req->operation = req->operation;
+	ac->new_req->op.search.base = req->op.search.base;
+	ac->new_req->op.search.scope = req->op.search.scope;
+	ac->new_req->op.search.tree = req->op.search.tree;
+	ac->new_req->op.search.attrs = req->op.search.attrs;
+	ac->new_req->context = ac;
+	ac->new_req->callback = ps_callback;
+	ldb_set_timeout_from_prev_req(module->ldb, req, ac->new_req);
+
+	req->handle = h;
+
+	return ldb_next_request(module, ac->new_req);
+}
+
+static int ps_continuation(struct ldb_handle *handle)
+{
+	struct ps_context *ac;
+
+	if (!handle || !handle->private_data) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	ac = talloc_get_type(handle->private_data, struct ps_context);
+
+	/* reset the requests handle */
+	ac->new_req->handle = NULL;
+
+	return ldb_next_request(handle->module, ac->new_req);
+}
+
+static int ps_wait_none(struct ldb_handle *handle)
+{
+	struct ps_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 ps_context);
+
+	ret = ldb_wait(ac->new_req->handle, LDB_WAIT_NONE);
+
+	if (ret != LDB_SUCCESS) {
+		handle->status = ret;
+		goto done;
+	}
+
+	if (ac->new_req->handle->status != LDB_SUCCESS) {
+		handle->status = ac->new_req->handle->status;
+		goto done;
+	}
+
+	if (ac->new_req->handle->state != LDB_ASYNC_DONE) {
+		return LDB_SUCCESS;
+	} 
+
+	/* see if we need to send another request for the next batch */
+	if (ac->pending) {
+		ret = ps_continuation(handle);
+		if (ret != LDB_SUCCESS) {
+			handle->status = ret;
+			goto done;
+		}
+
+		/* continue the search with the next request */
+		return LDB_SUCCESS;
+	}
+
+	ret = LDB_SUCCESS;
+
+done:
+	handle->state = LDB_ASYNC_DONE;
+	return ret;
+}
+
+static int ps_wait_all(struct ldb_handle *handle)
+{
+	int ret;
+
+	while (handle->state != LDB_ASYNC_DONE) {
+		ret = ps_wait_none(handle);
+		if (ret != LDB_SUCCESS) {
+			return ret;
+		}
+	}
+
+	return handle->status;
+}
+
+static int ps_wait(struct ldb_handle *handle, enum ldb_wait_type type)
+{
+	if (type == LDB_WAIT_ALL) {
+		return ps_wait_all(handle);
+	} else {
+		return ps_wait_none(handle);
+	}
+}
+
+static int ps_init(struct ldb_module *module)
+{
+	static const char *attrs[] = { "supportedControl", NULL };
+	struct private_data *data;
+	struct ldb_result *res = NULL;
+	int ret;
+
+	data = talloc(module, struct private_data);
+	if (data == NULL) {
+		return LDB_ERR_OTHER;
+	}
+	module->private_data = data;
+	data->paged_supported = False;
+	
+	/* find the supported controls */
+	ret = ldb_search(module->ldb,
+			 ldb_dn_new(module),
+			 LDB_SCOPE_BASE,
+			 "(objectClass=*)",
+			 attrs,
+			 &res);
+
+	if (ret != LDB_SUCCESS || res->count != 1) {
+		if (res) talloc_free(res);
+		return ldb_next_init(module);
+	}
+
+	if (ldb_msg_check_string_attribute(res->msgs[0],
+					   "supportedControl",
+					   LDB_CONTROL_PAGED_RESULTS_OID)) {
+
+		data->paged_supported = True;
+	}
+
+	talloc_free(res);
+
+	return ldb_next_init(module);
+}
+
+static const struct ldb_module_ops ps_ops = {
+	.name           = "paged_searches",
+	.search         = ps_search,
+	.wait           = ps_wait,
+	.init_context 	= ps_init
+};
+
+int ldb_paged_searches_init(void)
+{
+	return ldb_register_module(&ps_ops);
+}
+