分类: LINUX
2012-02-27 11:48:41
int open(const char *pathname, int flags, mode_t mode); --系统调用
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long sys_open(const char __user *filename, int flags, int mode) -- fs/open.c
/*对应内核中的open接口函数*/
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long do_sys_open(int dfd, const char __user *filename, int flags, int mode) --fs/open.c
/*用户空间的filename被拷贝到内核空间,获取当前可用的文件描述符*/
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static struct file *do_filp_open(int dfd, const char *filename, int flags, int mode) --fs/open.c
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int open_namei(int dfd, const char *pathname, int flag,
int mode, struct nameidata *nd)
/*获取该文件对应的nameidata结构.该函数执行完毕,接着调用下面函数。这两个函数是顺序被do_filp_open调用*/
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struct file *nameidata_to_filp(struct nameidata *nd, int flags) --fs/open.c
/*将nameidata 结构转换为打开的struct file结构*/
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static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
int flags, struct file *f,
int (*open)(struct inode *, struct file *)) --fs/open.c
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open = f->f_op->open;
open(inode, f); --fs/open.c
/*以上两行代码分别完成了open系统调用时执行实际文件对应内核的open方法,即scull_open*/