Why does su source code of Android call strcpy() after strdup()? Is this duplicated?

Question

The "su" source code snippet is shown as below:

void extract_uidgids() {
    ......
    clobberablegids = strdup(uidgids);
    strcpy(clobberablegids, uidgids);
    ......
}

why is strcpy() called after strdup()?

Thanks.