我们下来主要来分析内核对sendmsg的实现。...case SYS_SENDMSG:
err = __sys_sendmsg(a0, (struct user_msghdr __user *)a1,...(sock, msg, &msg_sys, flags, NULL, 0);}
后面的链路很长syssendmsg->__sys_sendmsg->sock_sendmsg->sock_sendmsg_nosec...(sock->ops->sendmsg, inet6_sendmsg,
inet_sendmsg, sock, msg,...Unix域对sendmsg的实现。