static gs_sigaction_func gs_signal_install_handler(void)
{
    struct sigaction act, oact;

    /*
     * It is important to set SA_NODEFER flag, so this signal is not added
     * to the signal mask of the calling process on entry to the signal handler.
     */
    sigemptyset(&act.sa_mask);
    act.sa_sigaction = gs_res_signal_handler;
    act.sa_flags = 0;
    act.sa_flags |= SA_SIGINFO;
    act.sa_flags |= SA_RESTART;

    if (sigaction(RES_SIGNAL, &act, &oact) < 0) {
        ereport(PANIC, (errcode(ERRCODE_INSUFFICIENT_RESOURCES), errmsg("not able to set up signal action handler")));
    }

    /* Return previously installed handler */
    return oact.sa_sigaction;
}

static void gs_res_signal_handler(int signo, siginfo_t* siginfo, void* context)
{
    void* signature = NULL;
    MemoryContext oldContext = CurrentMemoryContext;

    /*
     * Calculate the timer signature and mark the SIGALRM by myself. This is
     * because SIGALRM is dilivered by current thread's timer.
     */
    ThreadId thread_id = gs_thread_self();
    signature = (void*)(SIGALRM + thread_id);

    if (siginfo->si_value.sival_ptr == signature) {
        if (SIG_IGN != t_thrd.signal_slot->gssignal->handlerList[SIGALRM] &&
            SIG_DFL != t_thrd.signal_slot->gssignal->handlerList[SIGALRM]) {
            (t_thrd.signal_slot->gssignal->handlerList[SIGALRM])(SIGALRM);
        }

        CurrentMemoryContext = oldContext;
        return;
    }

    /* Hornour the signal */
    gs_signal_handle();

    CurrentMemoryContext = oldContext;
    return;
}