r18866: Jeremy and Volker have given the go-ahead on the group mapping ldb

code. Yay!

This first commit copies lib/ldb/ from Samba4. A huge congratulations
should go to Simo on this - he has put an enormous amount of work into
ldb, and it's great to see it go into the Samba3 tree.
(This used to be commit bbedf2e34315f5c420a3a05dfe22b1d5cf79f042)

1 files changed, 802 insertions, 0 deletions

diff --git a/source3/lib/ldb/common/ldb_msg.c b/source3/lib/ldb/common/ldb_msg.c
new file mode 100644
index 0000000000..52c6b82484
--- /dev/null
+++ b/source3/lib/ldb/common/ldb_msg.c
@@ -0,0 +1,802 @@
+/* 
+   ldb database library
+
+   Copyright (C) Andrew Tridgell  2004
+
+     ** 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 message component utility functions
+ *
+ *  Description: functions for manipulating ldb_message structures
+ *
+ *  Author: Andrew Tridgell
+ */
+
+#include "includes.h"
+#include "ldb/include/includes.h"
+
+/*
+  create a new ldb_message in a given memory context (NULL for top level)
+*/
+struct ldb_message *ldb_msg_new(void *mem_ctx)
+{
+	return talloc_zero(mem_ctx, struct ldb_message);
+}
+
+/*
+  find an element in a message by attribute name
+*/
+struct ldb_message_element *ldb_msg_find_element(const struct ldb_message *msg, 
+						 const char *attr_name)
+{
+	unsigned int i;
+	for (i=0;i<msg->num_elements;i++) {
+		if (ldb_attr_cmp(msg->elements[i].name, attr_name) == 0) {
+			return &msg->elements[i];
+		}
+	}
+	return NULL;
+}
+
+/*
+  see if two ldb_val structures contain exactly the same data
+  return 1 for a match, 0 for a mis-match
+*/
+int ldb_val_equal_exact(const struct ldb_val *v1, const struct ldb_val *v2)
+{
+	if (v1->length != v2->length) return 0;
+
+	if (v1->length == 0) return 1;
+
+	if (memcmp(v1->data, v2->data, v1->length) == 0) {
+		return 1;
+	}
+
+	return 0;
+}
+
+/*
+  find a value in an element
+  assumes case sensitive comparison
+*/
+struct ldb_val *ldb_msg_find_val(const struct ldb_message_element *el, 
+				 struct ldb_val *val)
+{
+	unsigned int i;
+	for (i=0;i<el->num_values;i++) {
+		if (ldb_val_equal_exact(val, &el->values[i])) {
+			return &el->values[i];
+		}
+	}
+	return NULL;
+}
+
+/*
+  duplicate a ldb_val structure
+*/
+struct ldb_val ldb_val_dup(void *mem_ctx, const struct ldb_val *v)
+{
+	struct ldb_val v2;
+	v2.length = v->length;
+	if (v->data == NULL) {
+		v2.data = NULL;
+		return v2;
+	}
+
+	/* the +1 is to cope with buggy C library routines like strndup
+	   that look one byte beyond */
+	v2.data = talloc_array(mem_ctx, uint8_t, v->length+1);
+	if (!v2.data) {
+		v2.length = 0;
+		return v2;
+	}
+
+	memcpy(v2.data, v->data, v->length);
+	((char *)v2.data)[v->length] = 0;
+	return v2;
+}
+
+/*
+  add an empty element to a message
+*/
+int ldb_msg_add_empty(struct ldb_message *msg, const char *attr_name, int flags)
+{
+	struct ldb_message_element *els;
+
+	if (! ldb_valid_attr_name(attr_name)) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	els = talloc_realloc(msg, msg->elements, 
+			     struct ldb_message_element, msg->num_elements+1);
+	if (!els) {
+		errno = ENOMEM;
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	els[msg->num_elements].values = NULL;
+	els[msg->num_elements].num_values = 0;
+	els[msg->num_elements].flags = flags;
+	els[msg->num_elements].name = talloc_strdup(els, attr_name);
+	if (!els[msg->num_elements].name) {
+		errno = ENOMEM;
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	msg->elements = els;
+	msg->num_elements++;
+
+	return LDB_SUCCESS;
+}
+
+/*
+  add an empty element to a message
+*/
+int ldb_msg_add(struct ldb_message *msg, 
+		const struct ldb_message_element *el, 
+		int flags)
+{
+	if (ldb_msg_add_empty(msg, el->name, flags) != 0) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	msg->elements[msg->num_elements-1] = *el;
+	msg->elements[msg->num_elements-1].flags = flags;
+
+	return LDB_SUCCESS;
+}
+
+/*
+  add a value to a message
+*/
+int ldb_msg_add_value(struct ldb_message *msg, 
+		      const char *attr_name,
+		      const struct ldb_val *val)
+{
+	struct ldb_message_element *el;
+	struct ldb_val *vals;
+
+	el = ldb_msg_find_element(msg, attr_name);
+	if (!el) {
+		ldb_msg_add_empty(msg, attr_name, 0);
+		el = ldb_msg_find_element(msg, attr_name);
+	}
+	if (!el) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	vals = talloc_realloc(msg, el->values, struct ldb_val, el->num_values+1);
+	if (!vals) {
+		errno = ENOMEM;
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+	el->values = vals;
+	el->values[el->num_values] = *val;
+	el->num_values++;
+
+	return LDB_SUCCESS;
+}
+
+
+/*
+  add a value to a message, stealing it into the 'right' place
+*/
+int ldb_msg_add_steal_value(struct ldb_message *msg, 
+			    const char *attr_name,
+			    struct ldb_val *val)
+{
+	int ret;
+	ret = ldb_msg_add_value(msg, attr_name, val);
+	if (ret == LDB_SUCCESS) {
+		struct ldb_message_element *el;
+		el = ldb_msg_find_element(msg, attr_name);
+		talloc_steal(el->values, val->data);
+	}
+	return ret;
+}
+
+
+/*
+  add a string element to a message
+*/
+int ldb_msg_add_string(struct ldb_message *msg, 
+		       const char *attr_name, const char *str)
+{
+	struct ldb_val val;
+
+	val.data = discard_const_p(uint8_t, str);
+	val.length = strlen(str);
+
+	return ldb_msg_add_value(msg, attr_name, &val);
+}
+
+/*
+  add a string element to a message, stealing it into the 'right' place
+*/
+int ldb_msg_add_steal_string(struct ldb_message *msg, 
+			     const char *attr_name, char *str)
+{
+	struct ldb_val val;
+
+	val.data = (uint8_t *)str;
+	val.length = strlen(str);
+
+	return ldb_msg_add_steal_value(msg, attr_name, &val);
+}
+
+/*
+  add a printf formatted element to a message
+*/
+int ldb_msg_add_fmt(struct ldb_message *msg, 
+		    const char *attr_name, const char *fmt, ...)
+{
+	struct ldb_val val;
+	va_list ap;
+	char *str;
+
+	va_start(ap, fmt);
+	str = talloc_vasprintf(msg, fmt, ap);
+	va_end(ap);
+
+	if (str == NULL) return LDB_ERR_OPERATIONS_ERROR;
+
+	val.data   = (uint8_t *)str;
+	val.length = strlen(str);
+
+	return ldb_msg_add_steal_value(msg, attr_name, &val);
+}
+
+/*
+  compare two ldb_message_element structures
+  assumes case senistive comparison
+*/
+int ldb_msg_element_compare(struct ldb_message_element *el1, 
+			    struct ldb_message_element *el2)
+{
+	unsigned int i;
+
+	if (el1->num_values != el2->num_values) {
+		return el1->num_values - el2->num_values;
+	}
+
+	for (i=0;i<el1->num_values;i++) {
+		if (!ldb_msg_find_val(el2, &el1->values[i])) {
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+/*
+  compare two ldb_message_element structures
+  comparing by element name
+*/
+int ldb_msg_element_compare_name(struct ldb_message_element *el1, 
+				 struct ldb_message_element *el2)
+{
+	return ldb_attr_cmp(el1->name, el2->name);
+}
+
+/*
+  convenience functions to return common types from a message
+  these return the first value if the attribute is multi-valued
+*/
+const struct ldb_val *ldb_msg_find_ldb_val(const struct ldb_message *msg, const char *attr_name)
+{
+	struct ldb_message_element *el = ldb_msg_find_element(msg, attr_name);
+	if (!el || el->num_values == 0) {
+		return NULL;
+	}
+	return &el->values[0];
+}
+
+int ldb_msg_find_attr_as_int(const struct ldb_message *msg, 
+			     const char *attr_name,
+			     int default_value)
+{
+	const struct ldb_val *v = ldb_msg_find_ldb_val(msg, attr_name);
+	if (!v || !v->data) {
+		return default_value;
+	}
+	return strtol((const char *)v->data, NULL, 0);
+}
+
+unsigned int ldb_msg_find_attr_as_uint(const struct ldb_message *msg, 
+				       const char *attr_name,
+				       unsigned int default_value)
+{
+	const struct ldb_val *v = ldb_msg_find_ldb_val(msg, attr_name);
+	if (!v || !v->data) {
+		return default_value;
+	}
+	return strtoul((const char *)v->data, NULL, 0);
+}
+
+int64_t ldb_msg_find_attr_as_int64(const struct ldb_message *msg, 
+				   const char *attr_name,
+				   int64_t default_value)
+{
+	const struct ldb_val *v = ldb_msg_find_ldb_val(msg, attr_name);
+	if (!v || !v->data) {
+		return default_value;
+	}
+	return strtoll((const char *)v->data, NULL, 0);
+}
+
+uint64_t ldb_msg_find_attr_as_uint64(const struct ldb_message *msg, 
+				     const char *attr_name,
+				     uint64_t default_value)
+{
+	const struct ldb_val *v = ldb_msg_find_ldb_val(msg, attr_name);
+	if (!v || !v->data) {
+		return default_value;
+	}
+	return strtoull((const char *)v->data, NULL, 0);
+}
+
+double ldb_msg_find_attr_as_double(const struct ldb_message *msg, 
+				   const char *attr_name,
+				   double default_value)
+{
+	const struct ldb_val *v = ldb_msg_find_ldb_val(msg, attr_name);
+	if (!v || !v->data) {
+		return default_value;
+	}
+	return strtod((const char *)v->data, NULL);
+}
+
+int ldb_msg_find_attr_as_bool(const struct ldb_message *msg, 
+			      const char *attr_name,
+			      int default_value)
+{
+	const struct ldb_val *v = ldb_msg_find_ldb_val(msg, attr_name);
+	if (!v || !v->data) {
+		return default_value;
+	}
+	if (strcasecmp((const char *)v->data, "FALSE") == 0) {
+		return 0;
+	}
+	if (strcasecmp((const char *)v->data, "TRUE") == 0) {
+		return 1;
+	}
+	return default_value;
+}
+
+const char *ldb_msg_find_attr_as_string(const struct ldb_message *msg, 
+					const char *attr_name,
+					const char *default_value)
+{
+	const struct ldb_val *v = ldb_msg_find_ldb_val(msg, attr_name);
+	if (!v || !v->data) {
+		return default_value;
+	}
+	return (const char *)v->data;
+}
+
+struct ldb_dn *ldb_msg_find_attr_as_dn(void *mem_ctx,
+				       const struct ldb_message *msg,
+				       const char *attr_name)
+{
+	const struct ldb_val *v;
+
+	v = ldb_msg_find_ldb_val(msg, attr_name);
+	if (!v || !v->data) {
+		return NULL;
+	}
+	return ldb_dn_explode(mem_ctx, (const char *)v->data);
+}
+
+/*
+  sort the elements of a message by name
+*/
+void ldb_msg_sort_elements(struct ldb_message *msg)
+{
+	qsort(msg->elements, msg->num_elements, sizeof(struct ldb_message_element), 
+	      (comparison_fn_t)ldb_msg_element_compare_name);
+}
+
+/*
+  shallow copy a message - copying only the elements array so that the caller
+  can safely add new elements without changing the message
+*/
+struct ldb_message *ldb_msg_copy_shallow(TALLOC_CTX *mem_ctx, 
+					 const struct ldb_message *msg)
+{
+	struct ldb_message *msg2;
+	int i;
+
+	msg2 = talloc(mem_ctx, struct ldb_message);
+	if (msg2 == NULL) return NULL;
+
+	*msg2 = *msg;
+	msg2->private_data = NULL;
+
+	msg2->elements = talloc_array(msg2, struct ldb_message_element, 
+				      msg2->num_elements);
+	if (msg2->elements == NULL) goto failed;
+
+	for (i=0;i<msg2->num_elements;i++) {
+		msg2->elements[i] = msg->elements[i];
+	}
+
+	return msg2;
+
+failed:
+	talloc_free(msg2);
+	return NULL;
+}
+
+
+/*
+  copy a message, allocating new memory for all parts
+*/
+struct ldb_message *ldb_msg_copy(TALLOC_CTX *mem_ctx, 
+				 const struct ldb_message *msg)
+{
+	struct ldb_message *msg2;
+	int i, j;
+
+	msg2 = ldb_msg_copy_shallow(mem_ctx, msg);
+	if (msg2 == NULL) return NULL;
+
+	msg2->dn = ldb_dn_copy(msg2, msg2->dn);
+	if (msg2->dn == NULL) goto failed;
+
+	for (i=0;i<msg2->num_elements;i++) {
+		struct ldb_message_element *el = &msg2->elements[i];
+		struct ldb_val *values = el->values;
+		el->name = talloc_strdup(msg2->elements, el->name);
+		if (el->name == NULL) goto failed;
+		el->values = talloc_array(msg2->elements, struct ldb_val, el->num_values);
+		for (j=0;j<el->num_values;j++) {
+			el->values[j] = ldb_val_dup(el->values, &values[j]);
+			if (el->values[j].data == NULL && values[j].length != 0) {
+				goto failed;
+			}
+		}
+	}
+
+	return msg2;
+
+failed:
+	talloc_free(msg2);
+	return NULL;
+}
+
+
+/*
+  canonicalise a message, merging elements of the same name
+*/
+struct ldb_message *ldb_msg_canonicalize(struct ldb_context *ldb, 
+					 const struct ldb_message *msg)
+{
+	int i;
+	struct ldb_message *msg2;
+
+	msg2 = ldb_msg_copy(ldb, msg);
+	if (msg2 == NULL) return NULL;
+
+	ldb_msg_sort_elements(msg2);
+
+	for (i=1;i<msg2->num_elements;i++) {
+		struct ldb_message_element *el1 = &msg2->elements[i-1];
+		struct ldb_message_element *el2 = &msg2->elements[i];
+		if (ldb_msg_element_compare_name(el1, el2) == 0) {
+			el1->values = talloc_realloc(msg2->elements, el1->values, struct ldb_val, 
+						       el1->num_values + el2->num_values);
+			if (el1->values == NULL) {
+				return NULL;
+			}
+			memcpy(el1->values + el1->num_values,
+			       el2->values,
+			       sizeof(struct ldb_val) * el2->num_values);
+			el1->num_values += el2->num_values;
+			talloc_free(discard_const_p(char, el2->name));
+			if (i+1<msg2->num_elements) {
+				memmove(el2, el2+1, sizeof(struct ldb_message_element) * 
+					(msg2->num_elements - (i+1)));
+			}
+			msg2->num_elements--;
+			i--;
+		}
+	}
+
+	return msg2;
+}
+
+
+/*
+  return a ldb_message representing the differences between msg1 and msg2. If you
+  then use this in a ldb_modify() call it can be used to save edits to a message
+*/
+struct ldb_message *ldb_msg_diff(struct ldb_context *ldb, 
+				 struct ldb_message *msg1,
+				 struct ldb_message *msg2)
+{
+	struct ldb_message *mod;
+	struct ldb_message_element *el;
+	unsigned int i;
+
+	mod = ldb_msg_new(ldb);
+
+	mod->dn = msg1->dn;
+	mod->num_elements = 0;
+	mod->elements = NULL;
+
+	msg2 = ldb_msg_canonicalize(ldb, msg2);
+	if (msg2 == NULL) {
+		return NULL;
+	}
+	
+	/* look in msg2 to find elements that need to be added
+	   or modified */
+	for (i=0;i<msg2->num_elements;i++) {
+		el = ldb_msg_find_element(msg1, msg2->elements[i].name);
+
+		if (el && ldb_msg_element_compare(el, &msg2->elements[i]) == 0) {
+			continue;
+		}
+
+		if (ldb_msg_add(mod, 
+				&msg2->elements[i],
+				el?LDB_FLAG_MOD_REPLACE:LDB_FLAG_MOD_ADD) != 0) {
+			return NULL;
+		}
+	}
+
+	/* look in msg1 to find elements that need to be deleted */
+	for (i=0;i<msg1->num_elements;i++) {
+		el = ldb_msg_find_element(msg2, msg1->elements[i].name);
+		if (!el) {
+			if (ldb_msg_add_empty(mod, 
+					      msg1->elements[i].name,
+					      LDB_FLAG_MOD_DELETE) != 0) {
+				return NULL;
+			}
+		}
+	}
+
+	return mod;
+}
+
+int ldb_msg_sanity_check(struct ldb_context *ldb, 
+			 const struct ldb_message *msg)
+{
+	int i, j;
+
+	/* basic check on DN */
+	if (msg->dn == NULL) {
+		/* TODO: return also an error string */
+		ldb_set_errstring(ldb, "ldb message lacks a DN!");
+		return LDB_ERR_INVALID_DN_SYNTAX;
+	}
+	if (msg->dn->comp_num == 0) {
+		/* root dse has empty dn */
+		ldb_set_errstring(ldb, "DN on new ldb message is '' (not permitted)!");
+		return LDB_ERR_ENTRY_ALREADY_EXISTS;
+	}
+
+	/* basic syntax checks */
+	for (i = 0; i < msg->num_elements; i++) {
+		for (j = 0; j < msg->elements[i].num_values; j++) {
+			if (msg->elements[i].values[j].length == 0) {
+				TALLOC_CTX *mem_ctx = talloc_new(ldb);
+				/* an attribute cannot be empty */
+				/* TODO: return also an error string */
+				ldb_asprintf_errstring(ldb, "Element %s has empty attribute in ldb message (%s)!",
+							    msg->elements[i].name, 
+							    ldb_dn_linearize(mem_ctx, msg->dn));
+				talloc_free(mem_ctx);
+				return LDB_ERR_INVALID_ATTRIBUTE_SYNTAX;
+			}
+		}
+	}
+
+	return LDB_SUCCESS;
+}
+
+
+
+
+/*
+  copy an attribute list. This only copies the array, not the elements
+  (ie. the elements are left as the same pointers)
+*/
+const char **ldb_attr_list_copy(TALLOC_CTX *mem_ctx, const char * const *attrs)
+{
+	const char **ret;
+	int i;
+	for (i=0;attrs[i];i++) /* noop */ ;
+	ret = talloc_array(mem_ctx, const char *, i+1);
+	if (ret == NULL) {
+		return NULL;
+	}
+	for (i=0;attrs[i];i++) {
+		ret[i] = attrs[i];
+	}
+	ret[i] = attrs[i];
+	return ret;
+}
+
+
+/*
+  copy an attribute list. This only copies the array, not the elements
+  (ie. the elements are left as the same pointers)
+*/
+const char **ldb_attr_list_copy_add(TALLOC_CTX *mem_ctx, const char * const *attrs, const char *new_attr)
+{
+	const char **ret;
+	int i;
+	for (i=0;attrs[i];i++) /* noop */ ;
+	ret = talloc_array(mem_ctx, const char *, i+2);
+	if (ret == NULL) {
+		return NULL;
+	}
+	for (i=0;attrs[i];i++) {
+		ret[i] = attrs[i];
+	}
+	ret[i] = new_attr;
+	ret[i+1] = NULL;
+	return ret;
+}
+
+
+/*
+  return 1 if an attribute is in a list of attributes, or 0 otherwise
+*/
+int ldb_attr_in_list(const char * const *attrs, const char *attr)
+{
+	int i;
+	for (i=0;attrs[i];i++) {
+		if (ldb_attr_cmp(attrs[i], attr) == 0) {
+			return 1;
+		}
+	}
+	return 0;
+}
+
+
+/*
+  rename the specified attribute in a search result
+*/
+int ldb_msg_rename_attr(struct ldb_message *msg, const char *attr, const char *replace)
+{
+	struct ldb_message_element *el = ldb_msg_find_element(msg, attr);
+	if (el == NULL) {
+		return LDB_SUCCESS;
+	}
+	el->name = talloc_strdup(msg->elements, replace);
+	if (el->name == NULL) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+	return LDB_SUCCESS;
+}
+
+
+/*
+  copy the specified attribute in a search result to a new attribute
+*/
+int ldb_msg_copy_attr(struct ldb_message *msg, const char *attr, const char *replace)
+{
+	struct ldb_message_element *el = ldb_msg_find_element(msg, attr);
+	if (el == NULL) {
+		return LDB_SUCCESS;
+	}
+	if (ldb_msg_add(msg, el, 0) != 0) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+	return ldb_msg_rename_attr(msg, attr, replace);
+}
+
+
+/*
+  remove the specified attribute in a search result
+*/
+void ldb_msg_remove_attr(struct ldb_message *msg, const char *attr)
+{
+	struct ldb_message_element *el = ldb_msg_find_element(msg, attr);
+	if (el) {
+		int n = (el - msg->elements);
+		if (n != msg->num_elements-1) {
+			memmove(el, el+1, ((msg->num_elements-1) - n)*sizeof(*el));
+		}
+		msg->num_elements--;
+	}
+}
+
+/*
+  return a LDAP formatted time string
+*/
+char *ldb_timestring(TALLOC_CTX *mem_ctx, time_t t)
+{
+	struct tm *tm = gmtime(&t);
+
+	if (!tm) {
+		return NULL;
+	}
+
+	/* formatted like: 20040408072012.0Z */
+	return talloc_asprintf(mem_ctx, 
+			       "%04u%02u%02u%02u%02u%02u.0Z",
+			       tm->tm_year+1900, tm->tm_mon+1,
+			       tm->tm_mday, tm->tm_hour, tm->tm_min,
+			       tm->tm_sec);
+}
+
+
+/*
+  convert a LDAP time string to a time_t. Return 0 if unable to convert
+*/
+time_t ldb_string_to_time(const char *s)
+{
+	struct tm tm;
+	
+	if (s == NULL) return 0;
+	
+	memset(&tm, 0, sizeof(tm));
+	if (sscanf(s, "%04u%02u%02u%02u%02u%02u", 
+		   &tm.tm_year, &tm.tm_mon, &tm.tm_mday, 
+		   &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
+		return 0;
+	}
+	tm.tm_year -= 1900;
+	tm.tm_mon -= 1;
+	
+	return timegm(&tm);
+}
+
+
+/*
+  dump a set of results to a file. Useful from within gdb
+*/
+void ldb_dump_results(struct ldb_context *ldb, struct ldb_result *result, FILE *f)
+{
+	int i;
+
+	for (i = 0; i < result->count; i++) {
+		struct ldb_ldif ldif;
+		fprintf(f, "# record %d\n", i+1);
+		ldif.changetype = LDB_CHANGETYPE_NONE;
+		ldif.msg = result->msgs[i];
+		ldb_ldif_write_file(ldb, f, &ldif);
+	}
+}
+
+int ldb_msg_check_string_attribute(const struct ldb_message *msg, const char *name, const char *value)
+{
+	struct ldb_message_element *el;
+	struct ldb_val val;
+	
+	el = ldb_msg_find_element(msg, name);
+	if (el == NULL)
+		return 0;
+
+	val.data = discard_const(value);
+	val.length = strlen(value);
+
+	if (ldb_msg_find_val(el, &val))
+		return 1;
+
+	return 0;
+}