uid_from_user
if (uid_from_user(hd->uname, &(arcn->sb.st_uid)) < 0)
int uid_from_user(const char *, uid_t *);
r = uid_from_user(argv[i], &u);
r = uid_from_user(argv[i], &u);
if (uid_from_user(owner, &uid) == -1) {
if (uid_from_user(value, &uid) == 0)
if (uid_from_user(val, &uid) == -1)