socket();
bind();
listen()
while(1)
{
accept();
if( fork() ==0 )
{
if( fork() == 0 )
{
while(1)
{
read();
process();
write();
}
close();
exit();
}
else
{
exit(0);//子进程退出，孙子进程的父进程变成init
}
}
close();
}