file_opration操作在linux系统中非常多，今天给大家分析一下这个程序的原理。

file_operations 在内核中定义linux/fs.h

  struct file_operations {

  struct module *owner;

  loff_t (*llseek) (struct file *, loff_t, int);

        ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);

  ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);

  unsigned int (*poll) (struct file *, struct poll_table_struct *);

  int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);

  int (*mmap) (struct file *, struct vm_area_struct *);

  int (*open) (struct inode *, struct file *);

  int (*release) (struct inode *, struct file *);

  int (*fsync) (struct file *, struct dentry *, int datasync);

  ……

  };

其中每个函数的结构及功能如下：

open逆操作

我们自己写的时候按照相关功能调用即可。