r18830: ensure backends aren't added twice (needed for samba3)

(This used to be commit 54b864b491d8a10c28833d28b764262503a72e91)

1 files changed, 19 insertions, 13 deletions

diff --git a/source4/lib/ldb/common/ldb.c b/source4/lib/ldb/common/ldb.c
index 1aae76bad6..760a311383 100644
--- a/source4/lib/ldb/common/ldb.c
+++ b/source4/lib/ldb/common/ldb.c
@@ -61,6 +61,21 @@ static struct ldb_backend {
 	ldb_connect_fn connect_fn;
 	struct ldb_backend *prev, *next;
 } *ldb_backends = NULL;
+
+
+static ldb_connect_fn ldb_find_backend(const char *url)
+{
+	struct ldb_backend *backend;
+
+	for (backend = ldb_backends; backend; backend = backend->next) {
+		if (strncmp(backend->name, url, strlen(backend->name)) == 0) {
+			return backend->connect_fn;
+		}
+	}
+
+	return NULL;
+}
+
 /*
  register a new ldb backend
 */
@@ -68,6 +83,10 @@ int ldb_register_backend(const char *url_prefix, ldb_connect_fn connectfn)
 {
 	struct ldb_backend *backend = talloc(talloc_autofree_context(), struct ldb_backend);
 
+	if (ldb_find_backend(url_prefix)) {
+		return LDB_SUCCESS;
+	}
+
 	/* Maybe check for duplicity here later on? */
 
 	backend->name = talloc_strdup(backend, url_prefix);
@@ -77,19 +96,6 @@ int ldb_register_backend(const char *url_prefix, ldb_connect_fn connectfn)
 	return LDB_SUCCESS;
 }
 
-static ldb_connect_fn ldb_find_backend(const char *url)
-{
-	struct ldb_backend *backend;
-
-	for (backend = ldb_backends; backend; backend = backend->next) {
-		if (strncmp(backend->name, url, strlen(backend->name)) == 0) {
-			return backend->connect_fn;
-		}
-	}
-
-	return NULL;
-}
-
 /* 
    Return the ldb module form of a database. The URL can either be one of the following forms
    ldb://path