close fds when finished
close fds when finished

wfxiang08/tcpcopy,ycaihua/tcpcopy,daodaoliang/tcpcopy,eliteYang/tcpcopy,liviusATnetskope/second,ycaihua/tcpcopy,eliteYang/tcpcopy,horryq/tcpcopy,sshling/tcpcopy,u20024804/tcpcopy,daodaoliang/tcpcopy,sshling/tcpcopy,wfxiang08/tcpcopy,left2right/tcpcopy,left2right/tcpcopy,caosiyang/tcpcopy,u20024804/tcpcopy,horryq/tcpcopy,liviusATnetskope/second,caosiyang/tcpcopy