Mutex

int green_mutex_lock(green_mutex_t *mutex) {
    // block timer interrupt
    sigprocmask(SIG_BLOCK, &block, NULL);

    green_t *susp = running;
    while(mutex->taken) {
        // suspend the running thread. Should I have a susp list?
        // add susp to susp queue
        if (mutex->susp == NULL){
            mutex->susp = running;
        }
        else {
            green_t* current = mutex->susp;
            while(current->next != NULL){
                current = current->next;
            }
            current->next = running;
        }

        // select the next thread for execution
        struct green_t* next = myDeQueue();
        // find the next thread
        running = next;
        swapcontext(susp->context, next->context);
    }
    // take the lock. This is enough, the caller function will wait until it gets back, and do whatever with the locks.
    mutex->taken = TRUE;
    mutex->susp = running;

    // unblock
    sigprocmask(SIG_UNBLOCK, &block, NULL);
    return 0;
}
int green_mutex_unlock(green_mutex_t *mutex) {
    // block timer interrupt
    sigprocmask(SIG_BLOCK, &block, NULL);
    // move suspended threads to ready queue
    while (mutex->susp != NULL){
        myEnQueue(mutex->susp);
        mutex->susp = mutex->susp->next;
    }
    // release lock
    mutex->taken = FALSE;
    // unblock
    sigprocmask(SIG_UNBLOCK, &block, NULL);
    return 0;
}