+int lc_setgid(lua_State* L)
+{
+ int gid = -1;
+ if(lua_gettop(L) < 1)
+ return 0;
+ if(!lua_isnumber(L, 1) && lua_tostring(L, 1))
+ {
+ /* Passed GID is actually a string, so look up the GID */
+ struct group *g;
+ g = getgrnam(lua_tostring(L, 1));
+ if(!g)
+ {
+ lua_pushboolean(L, 0);
+ lua_pushstring(L, "no-such-group");
+ return 2;
+ }
+ gid = g->gr_gid;
+ }
+ else
+ {
+ gid = lua_tonumber(L, 1);
+ }
+
+ if(gid>-1)
+ {
+ /* Ok, attempt setgid */
+ errno = 0;
+ if(setgid(gid))
+ {
+ /* Fail */
+ lua_pushboolean(L, 0);
+ switch(errno)
+ {
+ case EINVAL:
+ lua_pushstring(L, "invalid-gid");
+ break;
+ case EPERM:
+ lua_pushstring(L, "permission-denied");
+ break;
+ default:
+ lua_pushstring(L, "unknown-error");
+ }
+ return 2;
+ }
+ else
+ {
+ /* Success! */
+ lua_pushboolean(L, 1);
+ return 1;
+ }
+ }
+
+ /* Seems we couldn't find a valid GID to switch to */
+ lua_pushboolean(L, 0);
+ lua_pushstring(L, "invalid-gid");
+ return 2;
+}
+
+int lc_umask(lua_State* L)
+{
+ char old_mode_string[7];
+ mode_t old_mode = umask(strtoul(luaL_checkstring(L, 1), NULL, 8));
+
+ snprintf(old_mode_string, sizeof(old_mode_string), "%03o", old_mode);
+ old_mode_string[sizeof(old_mode_string)-1] = 0;
+ lua_pushstring(L, old_mode_string);
+
+ return 1;
+}
+
+int lc_mkdir(lua_State* L)
+{
+ int ret = mkdir(luaL_checkstring(L, 1), S_IRUSR | S_IWUSR | S_IXUSR
+ | S_IRGRP | S_IWGRP | S_IXGRP
+ | S_IROTH | S_IXOTH); /* mode 775 */
+
+ lua_pushboolean(L, ret==0);
+ if(ret)
+ {
+ lua_pushstring(L, strerror(errno));
+ return 2;
+ }
+ return 1;
+}
+