Function lwp_create

components/lwp/lwp_pid.c:628–690

* @brief Create a new lightweight process (LWP) * * @param[in] flags Creation flags that control LWP behavior * - LWP_CREATE_FLAG_NOTRACE_EXEC: Don't trace exec operations * - LWP_CREATE_FLAG_ALLOC_PID: Allocate a PID for the LWP * - LWP_CREATE_FLAG_INIT_USPACE: Initialize user space * * @return Pointer to newly created LWP structure on success * - RT_NULL on fa

 *        - RT_NULL on failure (pid allocation failed or user space init failed)
 */
rt_lwp_t lwp_create(rt_base_t flags)
{
    pid_t pid;
    rt_lwp_t new_lwp = rt_calloc(1, sizeof(struct rt_lwp));

    if (new_lwp)
    {
        /* minimal setup of lwp object */
        new_lwp->ref = 1;
#ifdef RT_USING_SMP
        new_lwp->bind_cpu = RT_CPUS_NR;
#endif
        new_lwp->exe_file = RT_NULL;
        rt_list_init(&new_lwp->t_grp);
        rt_list_init(&new_lwp->pgrp_node);
        rt_list_init(&new_lwp->timer);
        lwp_user_object_lock_init(new_lwp);
        rt_wqueue_init(&new_lwp->wait_queue);
        rt_wqueue_init(&new_lwp->waitpid_waiters);
        lwp_signal_init(&new_lwp->signal);
        rt_mutex_init(&new_lwp->lwp_lock, "lwp_lock", RT_IPC_FLAG_PRIO);

        if (flags & LWP_CREATE_FLAG_NOTRACE_EXEC)
            new_lwp->did_exec = RT_TRUE;

        /* lwp with pid */
        if (flags & LWP_CREATE_FLAG_ALLOC_PID)
        {
            lwp_pid_lock_take();
            pid = lwp_pid_get_locked();
            if (pid == 0)
            {
                lwp_user_object_lock_destroy(new_lwp);
                rt_free(new_lwp);
                new_lwp = RT_NULL;
                LOG_E("%s: pid slot fulled", __func__);
            }
            else
            {
                new_lwp->pid = pid;
                lwp_pid_set_lwp_locked(pid, new_lwp);
            }
            lwp_pid_lock_release();
        }
        rt_memset(&new_lwp->rt_rusage,0, sizeof(new_lwp->rt_rusage));

        if (flags & LWP_CREATE_FLAG_INIT_USPACE)
        {
            rt_err_t error = lwp_user_space_init(new_lwp, 0);
            if (error)
            {
                lwp_pid_put(new_lwp);
                lwp_user_object_lock_destroy(new_lwp);
                rt_free(new_lwp);
                new_lwp = RT_NULL;
                LOG_E("%s: failed to initialize user space", __func__);
            }
        }