xref: /linux-6.15/include/linux/namei.h (revision 4bedea94)
1 #ifndef _LINUX_NAMEI_H
2 #define _LINUX_NAMEI_H
3 
4 #include <linux/linkage.h>
5 
6 struct vfsmount;
7 
8 struct open_intent {
9 	int	flags;
10 	int	create_mode;
11 };
12 
13 enum { MAX_NESTED_LINKS = 5 };
14 
15 struct nameidata {
16 	struct dentry	*dentry;
17 	struct vfsmount *mnt;
18 	struct qstr	last;
19 	unsigned int	flags;
20 	int		last_type;
21 	unsigned	depth;
22 	char *saved_names[MAX_NESTED_LINKS + 1];
23 
24 	/* Intent data */
25 	union {
26 		struct open_intent open;
27 	} intent;
28 };
29 
30 /*
31  * Type of the last component on LOOKUP_PARENT
32  */
33 enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
34 
35 /*
36  * The bitmask for a lookup event:
37  *  - follow links at the end
38  *  - require a directory
39  *  - ending slashes ok even for nonexistent files
40  *  - internal "there are more path compnents" flag
41  *  - locked when lookup done with dcache_lock held
42  *  - dentry cache is untrusted; force a real lookup
43  */
44 #define LOOKUP_FOLLOW		 1
45 #define LOOKUP_DIRECTORY	 2
46 #define LOOKUP_CONTINUE		 4
47 #define LOOKUP_PARENT		16
48 #define LOOKUP_NOALT		32
49 #define LOOKUP_REVAL		64
50 /*
51  * Intent data
52  */
53 #define LOOKUP_OPEN		(0x0100)
54 #define LOOKUP_CREATE		(0x0200)
55 #define LOOKUP_ACCESS		(0x0400)
56 
57 extern int FASTCALL(__user_walk(const char __user *, unsigned, struct nameidata *));
58 #define user_path_walk(name,nd) \
59 	__user_walk(name, LOOKUP_FOLLOW, nd)
60 #define user_path_walk_link(name,nd) \
61 	__user_walk(name, 0, nd)
62 extern int FASTCALL(path_lookup(const char *, unsigned, struct nameidata *));
63 extern int FASTCALL(path_walk(const char *, struct nameidata *));
64 extern int FASTCALL(link_path_walk(const char *, struct nameidata *));
65 extern void path_release(struct nameidata *);
66 extern void path_release_on_umount(struct nameidata *);
67 
68 extern struct dentry * lookup_one_len(const char *, struct dentry *, int);
69 extern struct dentry * lookup_hash(struct qstr *, struct dentry *);
70 
71 extern int follow_down(struct vfsmount **, struct dentry **);
72 extern int follow_up(struct vfsmount **, struct dentry **);
73 
74 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
75 extern void unlock_rename(struct dentry *, struct dentry *);
76 
77 static inline void nd_set_link(struct nameidata *nd, char *path)
78 {
79 	nd->saved_names[nd->depth] = path;
80 }
81 
82 static inline char *nd_get_link(struct nameidata *nd)
83 {
84 	return nd->saved_names[nd->depth];
85 }
86 
87 #endif /* _LINUX_NAMEI_H */
88