Function sys_sched_getaffinity

components/lwp/lwp_syscall.c:8623–8686

* @brief Get the CPU affinity mask of a process. * * This function retrieves the CPU affinity mask for a specified process. The affinity mask indicates which CPUs the * process is allowed to execute on. The process can run on any of the CPUs represented by the bits set in the mask. * * @param[in] pid The process ID of the process whose CPU affinity is to be retrieved. If `pid` is `0`, the

 * @see sys_sched_setaffinity(), sys_getcpu()
 */
sysret_t sys_sched_getaffinity(const pid_t pid, size_t size, void *set)
{
#ifdef ARCH_MM_MMU
    LWP_DEF_RETURN_CODE(rc);
    void *mask;
    struct rt_lwp *lwp;

    if (size <= 0 || size > sizeof(cpu_set_t))
    {
        return -EINVAL;
    }
    if (!lwp_user_accessable(set, size))
    {
        return -EFAULT;
    }
    mask = kmem_get(size);
    if (!mask)
    {
        return -ENOMEM;
    }

    CPU_ZERO_S(size, mask);

    lwp_pid_lock_take();
    lwp = lwp_from_pid_locked(pid);

    if (!lwp)
    {
        rc = -ESRCH;
    }
    else
    {
#ifdef RT_USING_SMP
        if (lwp->bind_cpu == RT_CPUS_NR)    /* not bind */
        {
            for(int i = 0; i < RT_CPUS_NR; i++)
            {
                CPU_SET_S(i, size, mask);
            }
        }
        else /* set bind cpu */
        {
            /* TODO: only single-core bindings are now supported of rt-smart */
            CPU_SET_S(lwp->bind_cpu, size, mask);
        }
#else
        CPU_SET_S(0, size, mask);
#endif

        if (lwp_put_to_user(set, mask, size) != size)
            rc = -EFAULT;
        else
            rc = size;
    }

    lwp_pid_lock_release();

    kmem_put(mask);