SET_GROUP_FROM
if (mkdir(SET_GROUP_FROM, 0777))
if (mount("testing", SET_GROUP_FROM, "tmpfs", MS_NOATIME | MS_NODEV,
if (mount(SET_GROUP_FROM, SET_GROUP_TO, NULL, MS_BIND, NULL))
if (mount(NULL, SET_GROUP_FROM, NULL, MS_SHARED, 0))
ret = syscall(__NR_move_mount, AT_FDCWD, SET_GROUP_FROM,