Function _fetch_robust_entry

components/lwp/lwp_futex.c:1030–1050

* @brief Fetches a robust futex list entry from user space * * @param[out] entry Pointer to store the retrieved robust list entry * @param[in] head Pointer to the head of the robust list in user space * @param[out] is_pi Pointer to store the PI flag status * * @return Operation status * - 0 on success * - EFAULT if user space access fails * * @note This helper function sa

 *       from user space and extracts the PI (Priority Inheritance) flag.
 */
rt_inline int _fetch_robust_entry(struct robust_list **entry,
                                  struct robust_list **head, rt_bool_t *is_pi)
{
    unsigned long uentry;

    if (!lwp_user_accessable((void *)head, sizeof(*head)))
    {
        return -EFAULT;
    }

    if (lwp_get_from_user(&uentry, (void *)head, sizeof(*head)) !=
        sizeof(*head))
    {
        return -EFAULT;
    }

    *entry = (void *)(uentry & ~1UL);
    *is_pi = uentry & 1;

    return 0;
}

/**
 * @brief Handles futex cleanup when a thread dies