OpenSSL::X509::Extension#oid=

static VALUE
ossl_x509ext_set_oid(VALUE self, VALUE oid)
{
    X509_EXTENSION *ext;
    ASN1_OBJECT *obj;

    GetX509Ext(self, ext);
    obj = OBJ_txt2obj(StringValueCStr(oid), 0);
    if (!obj)
        ossl_raise(eX509ExtError, "OBJ_txt2obj");
    if (!X509_EXTENSION_set_object(ext, obj)) {
        ASN1_OBJECT_free(obj);
        ossl_raise(eX509ExtError, "X509_EXTENSION_set_object");
    }
    ASN1_OBJECT_free(obj);

    return oid;
}