1 files changed, 59 insertions, 0 deletions
diff --git a/src/auth/userdb-prefetch.c b/src/auth/userdb-prefetch.c
new file mode 100644
index 0000000..a5730b9
--- /dev/null
+++ b/src/auth/userdb-prefetch.c
@@ -0,0 +1,59 @@
+/* Copyright (c) 2004-2018 Dovecot authors, see the included COPYING file */
+
+#include "auth-common.h"
+#include "userdb.h"
+
+#ifdef USERDB_PREFETCH
+
+#include "str.h"
+#include "var-expand.h"
+
+
+static void prefetch_lookup(struct auth_request *auth_request,
+			    userdb_callback_t *callback)
+{
+	/* auth_request_set_field() should have already placed the userdb_*
+	   values to userdb_reply. */
+	if (!auth_request->userdb_prefetch_set) {
+		if (auth_request_get_auth(auth_request)->userdbs->next == NULL) {
+			/* no other userdbs */
+			if (auth_request->userdb_lookup) {
+				e_error(authdb_event(auth_request),
+					"userdb lookup not possible with only userdb prefetch");
+			} else {
+				e_error(authdb_event(auth_request),
+					"passdb didn't return userdb entries");
+			}
+			callback(USERDB_RESULT_INTERNAL_FAILURE, auth_request);
+			return;
+		}
+		/* more userdbs, they may know the user */
+		e_debug(authdb_event(auth_request),
+			"passdb didn't return userdb entries, "
+			"trying the next userdb");
+		callback(USERDB_RESULT_USER_UNKNOWN, auth_request);
+		return;
+	}
+
+	e_debug(authdb_event(auth_request), "success");
+	callback(USERDB_RESULT_OK, auth_request);
+}
+
+struct userdb_module_interface userdb_prefetch = {
+	"prefetch",
+
+	NULL,
+	NULL,
+	NULL,
+
+	prefetch_lookup,
+
+	NULL,
+	NULL,
+	NULL
+};
+#else
+struct userdb_module_interface userdb_prefetch = {
+	.name = "prefetch"
+};
+#endif