Function sys_poll

components/lwp/lwp_syscall.c:895–930

* @brief Monitors multiple file descriptors to see if they are ready for I/O. * * This system call monitors the file descriptors specified in `fds` for any * I/O events such as readiness for reading, writing, or exceptional conditions. * It waits up to the specified timeout and returns with information about which * file descriptors are ready for the requested operations. * * @param fds An

 * @see sys_select(), poll(), select()
 */
sysret_t sys_poll(struct pollfd *fds, nfds_t nfds, int timeout)
{
    int ret = -1;
#ifdef ARCH_MM_MMU
    struct pollfd *kfds = RT_NULL;

    if (!lwp_user_accessable((void *)fds, nfds * sizeof *fds))
    {
        return -EFAULT;
    }

    kfds = (struct pollfd *)kmem_get(nfds * sizeof *kfds);
    if (!kfds)
    {
        return -ENOMEM;
    }

    lwp_get_from_user(kfds, fds, nfds * sizeof *kfds);

    ret = poll(kfds, nfds, timeout);
    if (ret > 0)
    {
        lwp_put_to_user(fds, kfds, nfds * sizeof *kfds);
    }

    kmem_put(kfds);
    return ret;
#else
    if (!lwp_user_accessable((void *)fds, nfds * sizeof *fds))
    {
        return -EFAULT;
    }
    ret = poll(fds, nfds, timeout);
    return ret;
#endif /* ARCH_MM_MMU */
}

/**
 * @brief Monitors multiple file descriptors for readiness to perform I/O operations.