Function sys_sendmsg

components/lwp/lwp_syscall.c:5970–6019

* @brief Sends a message from a socket using scatter-gather I/O. * * This system call sends data from multiple buffers specified in the `msghdr` structure. It is particularly * useful for advanced socket operations requiring ancillary data or scatter-gather I/O. * * @param[in] socket The socket descriptor through which the data will be sent. The socket must be * valid a

 * @see sys_send(), sys_sendto(), sys_recvmsg()
 */
sysret_t sys_sendmsg(int socket, const struct msghdr *msg, int flags)
{
    int flgs, ret = -1;
    struct msghdr kmsg;
#ifdef ARCH_MM_MMU
    void *msg_control;
    struct iovec *uiov, *kiov;
#endif
    if (!msg)
    {
        return -EPERM;
    }

    flgs = netflags_muslc_2_lwip(flags);

#ifdef ARCH_MM_MMU
    ret = copy_msghdr_from_user(&kmsg, (struct msghdr *)msg, &uiov, &msg_control);

    if (!ret)
    {
        kiov = kmsg.msg_iov;

        for (int i = 0; i < kmsg.msg_iovlen; ++i)
        {
            lwp_get_from_user(kiov->iov_base, uiov->iov_base, kiov->iov_len);

            ++kiov;
            ++uiov;
        }

        lwp_get_from_user(kmsg.msg_control, msg_control, kmsg.msg_controllen);

        ret = sendmsg(socket, &kmsg, flgs);

        kmem_put(kmsg.msg_iov->iov_base);
        kmem_put(kmsg.msg_iov);
    }
#else
    rt_memcpy(&kmsg, msg, sizeof(kmsg));

    ret = sendmsg(socket, &kmsg, flgs);

    if (!ret)
    {
        msg->msg_flags = kmsg.msg_flags;
    }
#endif /* ARCH_MM_MMU */

    return (ret < 0 ? GET_ERRNO() : ret);
}

/**
 * @brief Sends data to a specific address using a socket.