Function sys_getsid

components/lwp/lwp_session.c:348–377

* getsid() returns the session ID of the process with process ID pid. * If pid is 0, getsid() returns the session ID of the calling process. */

 *  If pid is 0, getsid() returns the session ID of the calling process.
 */
sysret_t sys_getsid(pid_t pid)
{
    rt_lwp_t process, self_process;
    pid_t sid;

    lwp_pid_lock_take();
    process = lwp_from_pid_locked(pid);
    lwp_pid_lock_release();

    if (process == RT_NULL)
    {
        return -ESRCH;
    }

    self_process = lwp_self();
    sid = lwp_sid_get_byprocess(process);

    if (sid != lwp_sid_get_byprocess(self_process))
    {
        /**
         * A process with process ID pid exists, but it is not in the same session as the calling process,
         *  and the implementation considers this an error.
         *
         * Note: Linux does not return EPERM.
         */
        return -EPERM;
    }

    return sid;
}

#ifdef RT_USING_FINSH