xref: /linux-6.15/include/linux/namei.h (revision 1795cf48)
1 #ifndef _LINUX_NAMEI_H
2 #define _LINUX_NAMEI_H
3 
4 #include <linux/dcache.h>
5 #include <linux/linkage.h>
6 #include <linux/path.h>
7 
8 struct vfsmount;
9 
10 struct open_intent {
11 	int	flags;
12 	int	create_mode;
13 	struct file *file;
14 };
15 
16 enum { MAX_NESTED_LINKS = 8 };
17 
18 struct nameidata {
19 	struct path	path;
20 	struct qstr	last;
21 	unsigned int	flags;
22 	int		last_type;
23 	unsigned	depth;
24 	char *saved_names[MAX_NESTED_LINKS + 1];
25 
26 	/* Intent data */
27 	union {
28 		struct open_intent open;
29 	} intent;
30 };
31 
32 /*
33  * Type of the last component on LOOKUP_PARENT
34  */
35 enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
36 
37 /*
38  * The bitmask for a lookup event:
39  *  - follow links at the end
40  *  - require a directory
41  *  - ending slashes ok even for nonexistent files
42  *  - internal "there are more path compnents" flag
43  *  - locked when lookup done with dcache_lock held
44  *  - dentry cache is untrusted; force a real lookup
45  */
46 #define LOOKUP_FOLLOW		 1
47 #define LOOKUP_DIRECTORY	 2
48 #define LOOKUP_CONTINUE		 4
49 #define LOOKUP_PARENT		16
50 #define LOOKUP_REVAL		64
51 /*
52  * Intent data
53  */
54 #define LOOKUP_OPEN		(0x0100)
55 #define LOOKUP_CREATE		(0x0200)
56 
57 extern int user_path_at(int, const char __user *, unsigned, struct path *);
58 
59 #define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
60 #define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
61 #define user_path_dir(name, path) \
62 	user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
63 
64 extern int path_lookup(const char *, unsigned, struct nameidata *);
65 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
66 			   const char *, unsigned int, struct nameidata *);
67 
68 extern int path_lookup_open(int dfd, const char *name, unsigned lookup_flags, struct nameidata *, int open_flags);
69 extern struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
70 		int (*open)(struct inode *, struct file *));
71 extern struct file *nameidata_to_filp(struct nameidata *nd, int flags);
72 extern void release_open_intent(struct nameidata *);
73 
74 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
75 extern struct dentry *lookup_one_noperm(const char *, struct dentry *);
76 
77 extern int follow_down(struct vfsmount **, struct dentry **);
78 extern int follow_up(struct vfsmount **, struct dentry **);
79 
80 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
81 extern void unlock_rename(struct dentry *, struct dentry *);
82 
83 static inline void nd_set_link(struct nameidata *nd, char *path)
84 {
85 	nd->saved_names[nd->depth] = path;
86 }
87 
88 static inline char *nd_get_link(struct nameidata *nd)
89 {
90 	return nd->saved_names[nd->depth];
91 }
92 
93 #endif /* _LINUX_NAMEI_H */
94