1 files changed, 95 insertions, 0 deletions
diff --git a/daemon/bindings/impl.c b/daemon/bindings/impl.c
new file mode 100644
index 0000000..8c48df8
--- /dev/null
+++ b/daemon/bindings/impl.c
@@ -0,0 +1,95 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-resolver@labs.nic.cz>
+ *  SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include <dirent.h>
+#include <lua.h>
+#include <lauxlib.h>
+#include <string.h>
+
+
+const char * lua_table_checkindices(lua_State *L, const char *keys[])
+{
+	/* Iterate over table at the top of the stack.
+	 * http://www.lua.org/manual/5.1/manual.html#lua_next */
+	for (lua_pushnil(L); lua_next(L, -2); lua_pop(L, 1)) {
+		lua_pop(L, 1); /* we don't need the value */
+		/* We need to copy the key, as _tostring() confuses _next().
+		 * https://www.lua.org/manual/5.1/manual.html#lua_tolstring */
+		lua_pushvalue(L, -1);
+		const char *key = lua_tostring(L, -1);
+		if (!key)
+			return "<NON-STRING_INDEX>";
+		for (const char **k = keys; ; ++k) {
+			if (*k == NULL)
+				return key;
+			if (strcmp(*k, key) == 0)
+				break;
+		}
+	}
+	return NULL;
+}
+
+/** Return table listing filenames in a given directory (ls -A). */
+static int kluautil_list_dir(lua_State *L)
+{
+	lua_newtable(L); // empty table even on errors
+
+	const char *path = lua_tolstring(L, 1, NULL);
+	if (!path) return 1;
+	DIR *dir = opendir(path);
+	if (!dir) return 1;
+
+	struct dirent *entry;
+	int lua_i = 1;
+	while ((entry = readdir(dir)) != NULL) {
+		if (strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) {
+			lua_pushstring(L, entry->d_name);
+			lua_rawseti(L, -2, lua_i++);
+		}
+	}
+
+	closedir(dir);
+	return 1;
+}
+
+
+/* Each of these just creates the correspondingly named lua table of functions. */
+int kr_bindings_cache   (lua_State *L); /* ./cache.c   */
+int kr_bindings_event   (lua_State *L); /* ./event.c   */
+int kr_bindings_modules (lua_State *L); /* ./modules.c */
+int kr_bindings_net     (lua_State *L); /* ./net.c     */
+int kr_bindings_worker  (lua_State *L); /* ./worker.c  */
+
+void kr_bindings_register(lua_State *L)
+{
+	kr_bindings_cache(L);
+	kr_bindings_event(L);
+	kr_bindings_modules(L);
+	kr_bindings_net(L);
+	kr_bindings_worker(L);
+
+	/* Finally some lua utils *written in C*, not really a binding. */
+	lua_register(L, "kluautil_list_dir", kluautil_list_dir);
+}
+
+void lua_error_p(lua_State *L, const char *fmt, ...)
+{
+	/* Add a stack trace and throw the result as a lua error. */
+	luaL_traceback(L, L, "error occurred here (config filename:lineno is at the bottom, if config is involved):", 0);
+	/* Push formatted custom message, prepended with "ERROR: ". */
+	lua_pushliteral(L, "\nERROR: ");
+	{
+		va_list args;
+		va_start(args, fmt);
+		lua_pushvfstring(L, fmt, args);
+		va_end(args);
+	}
+	lua_concat(L, 3);
+	lua_error(L);
+	/* TODO: we might construct a little more friendly trace by using luaL_where().
+	 * In particular, in case the error happens in a function that was called
+	 * directly from a config file (the most common case), there isn't much need
+	 * to format the trace in this heavy way. */
+}
+