lua: chdir and getcwd

src/lib/interpreter.c

@@ -305,6 +305,32 @@ static int lua_mkdtemp(lua_State *L) {
 	}
 }
 
+static int lua_chdir(lua_State *L) {
+	int param_count = lua_gettop(L);
+	if (param_count != 1)
+		return luaL_error(L, "chdir expects 1 parameter");
+	const char *path = luaL_checkstring(L, 1);
+	int result = chdir(path);
+	if (result == -1)
+		return luaL_error(L, "chdir to %s: %s", path, strerror(errno));
+	return 0;
+}
+
+static int lua_getcwd(lua_State *L) {
+	const char *result = NULL;
+	// An arbitrary length.
+	size_t s = 16;
+	while (!result) {
+		s *= 2;
+		char *buf = alloca(s);
+		result = getcwd(buf, s);
+		if (!result && errno != ERANGE)
+			return luaL_error(L, "getcwd: %s", strerror(errno));
+	}
+	lua_pushstring(L, result);
+	return 1;
+}
+
 struct injected_func {
 	int (*func)(lua_State *);
 	const char *name;
@@ -314,7 +340,9 @@ static const struct injected_func injected_funcs[] = {
 	{ lua_log, "log" },
 	{ lua_run_command, "run_command" },
 	{ lua_events_wait, "events_wait" },
-	{ lua_mkdtemp, "mkdtemp" }
+	{ lua_mkdtemp, "mkdtemp" },
+	{ lua_chdir, "chdir" },
+	{ lua_getcwd, "getcwd" }
 	/*
 	 * Note: watch_cancel is not provided, because it would be hell to
 	 * manage the dynamically allocated memory correctly and there doesn't

src/lib/lua_funcs.txt

@@ -84,3 +84,9 @@ mkdtemp([directory])::
   created as a subdirectory of the given directory, otherwise it is
   created inside `/tmp`. It returns path to the new directory, or
   `nil` and an error message.
+
+chdir(directory)::
+  Change the current working directory to the one provided.
+
+getcwd()::
+  Get the current working directory.

tests/Makefile.dir

@@ -18,7 +18,8 @@ C_TESTS := \
 
 LUA_TESTS := \
 	backend \
-	events
+	events \
+	interpreter
 
 define DO_C_TEST
 

tests/interpreter.lua

+--[[
+Copyright 2016, CZ.NIC z.s.p.o. (http://www.nic.cz/)
+
+This file is part of the turris updater.
+
+Updater is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+Updater 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with Updater.  If not, see <http://www.gnu.org/licenses/>.
+]]--
+
+require 'lunit'
+
+-- Some of the interpreter tests are in C, some are easier written in lua
+module("interpreter-tests", package.seeall, lunit.testcase)
+
+function test_dirs()
+	local top = os.getenv("S") or "."
+	chdir(top)
+	chdir("tests")
+	local dir = getcwd()
+	-- The current directory should be in tests now
+	assert_equal("/tests", dir:sub(-6))
+end