xref: /linux-6.15/include/linux/namei.h (revision 4f193362)
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 	struct file *file;
12 };
13 
14 enum { MAX_NESTED_LINKS = 5 };
15 
16 struct nameidata {
17 	struct dentry	*dentry;
18 	struct vfsmount *mnt;
19 	struct qstr	last;
20 	unsigned int	flags;
21 	int		last_type;
22 	unsigned	depth;
23 	char *saved_names[MAX_NESTED_LINKS + 1];
24 
25 	/* Intent data */
26 	union {
27 		struct open_intent open;
28 	} intent;
29 };
30 
31 /*
32  * Type of the last component on LOOKUP_PARENT
33  */
34 enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
35 
36 /*
37  * The bitmask for a lookup event:
38  *  - follow links at the end
39  *  - require a directory
40  *  - ending slashes ok even for nonexistent files
41  *  - internal "there are more path compnents" flag
42  *  - locked when lookup done with dcache_lock held
43  *  - dentry cache is untrusted; force a real lookup
44  */
45 #define LOOKUP_FOLLOW		 1
46 #define LOOKUP_DIRECTORY	 2
47 #define LOOKUP_CONTINUE		 4
48 #define LOOKUP_PARENT		16
49 #define LOOKUP_NOALT		32
50 #define LOOKUP_REVAL		64
51 /*
52  * Intent data
53  */
54 #define LOOKUP_OPEN		(0x0100)
55 #define LOOKUP_CREATE		(0x0200)
56 #define LOOKUP_ACCESS		(0x0400)
57 
58 extern int FASTCALL(__user_walk(const char __user *, unsigned, struct nameidata *));
59 extern int FASTCALL(__user_walk_fd(int dfd, const char __user *, unsigned, struct nameidata *));
60 #define user_path_walk(name,nd) \
61 	__user_walk_fd(AT_FDCWD, name, LOOKUP_FOLLOW, nd)
62 #define user_path_walk_link(name,nd) \
63 	__user_walk_fd(AT_FDCWD, name, 0, nd)
64 extern int FASTCALL(path_lookup(const char *, unsigned, struct nameidata *));
65 extern int FASTCALL(path_walk(const char *, struct nameidata *));
66 extern int FASTCALL(link_path_walk(const char *, struct nameidata *));
67 extern void path_release(struct nameidata *);
68 extern void path_release_on_umount(struct nameidata *);
69 
70 extern int __user_path_lookup_open(const char __user *, unsigned lookup_flags, struct nameidata *nd, int open_flags);
71 extern int path_lookup_open(int dfd, const char *name, unsigned lookup_flags, struct nameidata *, int open_flags);
72 extern struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
73 		int (*open)(struct inode *, struct file *));
74 extern struct file *nameidata_to_filp(struct nameidata *nd, int flags);
75 extern void release_open_intent(struct nameidata *);
76 
77 extern struct dentry * lookup_one_len(const char *, struct dentry *, int);
78 extern __deprecated_for_modules struct dentry * lookup_hash(struct nameidata *);
79 
80 extern int follow_down(struct vfsmount **, struct dentry **);
81 extern int follow_up(struct vfsmount **, struct dentry **);
82 
83 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
84 extern void unlock_rename(struct dentry *, struct dentry *);
85 
86 static inline void nd_set_link(struct nameidata *nd, char *path)
87 {
88 	nd->saved_names[nd->depth] = path;
89 }
90 
91 static inline char *nd_get_link(struct nameidata *nd)
92 {
93 	return nd->saved_names[nd->depth];
94 }
95 
96 #endif /* _LINUX_NAMEI_H */
97