xref: /linux-6.15/include/linux/namei.h (revision 71ccc212)
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 	struct path	root;
22 	unsigned int	flags;
23 	int		last_type;
24 	unsigned	depth;
25 	char *saved_names[MAX_NESTED_LINKS + 1];
26 
27 	/* Intent data */
28 	union {
29 		struct open_intent open;
30 	} intent;
31 };
32 
33 /*
34  * Type of the last component on LOOKUP_PARENT
35  */
36 enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
37 
38 /*
39  * The bitmask for a lookup event:
40  *  - follow links at the end
41  *  - require a directory
42  *  - ending slashes ok even for nonexistent files
43  *  - internal "there are more path components" flag
44  *  - locked when lookup done with dcache_lock held
45  *  - dentry cache is untrusted; force a real lookup
46  */
47 #define LOOKUP_FOLLOW		 1
48 #define LOOKUP_DIRECTORY	 2
49 #define LOOKUP_CONTINUE		 4
50 #define LOOKUP_PARENT		16
51 #define LOOKUP_REVAL		64
52 /*
53  * Intent data
54  */
55 #define LOOKUP_OPEN		0x0100
56 #define LOOKUP_CREATE		0x0200
57 #define LOOKUP_EXCL		0x0400
58 #define LOOKUP_RENAME_TARGET	0x0800
59 
60 extern int user_path_at(int, const char __user *, unsigned, struct path *);
61 
62 #define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
63 #define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
64 #define user_path_dir(name, path) \
65 	user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
66 
67 extern int kern_path(const char *, unsigned, struct path *);
68 
69 extern int path_lookup(const char *, unsigned, struct nameidata *);
70 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
71 			   const char *, unsigned int, struct nameidata *);
72 
73 extern struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
74 		int (*open)(struct inode *, struct file *));
75 
76 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
77 
78 extern int follow_down(struct path *);
79 extern int follow_up(struct path *);
80 
81 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
82 extern void unlock_rename(struct dentry *, struct dentry *);
83 
84 static inline void nd_set_link(struct nameidata *nd, char *path)
85 {
86 	nd->saved_names[nd->depth] = path;
87 }
88 
89 static inline char *nd_get_link(struct nameidata *nd)
90 {
91 	return nd->saved_names[nd->depth];
92 }
93 
94 static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
95 {
96 	((char *) name)[min(len, maxlen)] = '\0';
97 }
98 
99 #endif /* _LINUX_NAMEI_H */
100