linux-c目录文件相关

获取当前目录：https://blog.csdn.net/a351945755/article/details/20048111?utm_source=blogxgwz3

文件相关：
https://songlee24.github.io/2014/09/20/linux-get-directory/

stat结构体：
https://blog.csdn.net/tianmohust/article/details/6609470

获取相对路径对应的绝对路径
https://www.xuebuyuan.com/2961573.html