sys_dup3
asmlinkage long sys_dup3(unsigned int oldfd, unsigned int newfd, int flags);
__SYSCALL(__NR_dup3, sys_dup3)
return __sysret(sys_dup3(old, new, flags));
__SYSCALL(__NR_dup3, sys_dup3)
err = sys_dup3(tmp_fd, fixed_fd, O_CLOEXEC);