Function sys_setsid

components/lwp/lwp_session.c:299–342

* setsid() creates a new session if the calling process is not a process group leader. * The calling process is the leader of the new session (i.e., its session ID is made the same as its process ID). * The calling process also becomes the process group leader of a new process group in the session * (i.e., its process group ID is made the same as its process ID). */

 *      (i.e., its process group ID is made the same as its process ID).
 */
sysret_t sys_setsid(void)
{
    rt_lwp_t process;
    pid_t pid;
    rt_processgroup_t group;
    rt_session_t session;
    sysret_t err = 0;

    process = lwp_self();
    pid = lwp_to_pid(process);

    /**
     * if the calling process is already a process group leader.
     */
    if (lwp_pgrp_find(pid))
    {
        err = -EPERM;
        goto exit;
    }

    group = lwp_pgrp_create(process);
    if (group)
    {
        lwp_pgrp_move(group, process);
        session = lwp_session_create(process);
        if (session)
        {
            lwp_session_move(session, group);
        }
        else
        {
            lwp_pgrp_delete(group);
        }
        err = lwp_sid_get_bysession(session);
    }
    else
    {
        err = -ENOMEM;
    }


exit:
    return err;
}

/**
 * getsid() returns the session ID of the process with process ID pid.