Function sys_recvmsg

components/lwp/lwp_syscall.c:5721–5778

* @brief Receives a message from a socket using a message header structure. * * This system call is used to receive data and associated metadata from a socket. * It supports both stream-oriented and message-oriented sockets and allows control * over the behavior of the receiving operation via the `flags` parameter. * * @param[in] socket The socket descriptor from which the message will be

 * @see sys_sendmsg()
 */
sysret_t sys_recvmsg(int socket, 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, msg, &uiov, &msg_control);

    if (!ret)
    {
        ret = recvmsg(socket, &kmsg, flgs);

        if (ret < 0)
        {
            goto _free_res;
        }

        kiov = kmsg.msg_iov;

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

            ++kiov;
            ++uiov;
        }

        lwp_put_to_user(msg_control, kmsg.msg_control, kmsg.msg_controllen);
        lwp_put_to_user(&msg->msg_flags, &kmsg.msg_flags, sizeof(kmsg.msg_flags));

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

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

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

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