xref: /linux-6.15/include/linux/namei.h (revision facb4edc)
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 	struct file	*file;
23 	struct inode	*inode; /* path.dentry.d_inode */
24 	unsigned int	flags;
25 	unsigned	seq;
26 	int		last_type;
27 	unsigned	depth;
28 	char *saved_names[MAX_NESTED_LINKS + 1];
29 
30 	/* Intent data */
31 	union {
32 		struct open_intent open;
33 	} intent;
34 };
35 
36 /*
37  * Type of the last component on LOOKUP_PARENT
38  */
39 enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
40 
41 /*
42  * The bitmask for a lookup event:
43  *  - follow links at the end
44  *  - require a directory
45  *  - ending slashes ok even for nonexistent files
46  *  - internal "there are more path components" flag
47  *  - dentry cache is untrusted; force a real lookup
48  */
49 #define LOOKUP_FOLLOW		0x0001
50 #define LOOKUP_DIRECTORY	0x0002
51 #define LOOKUP_CONTINUE		0x0004
52 
53 #define LOOKUP_PARENT		0x0010
54 #define LOOKUP_REVAL		0x0020
55 #define LOOKUP_RCU		0x0040
56 /*
57  * Intent data
58  */
59 #define LOOKUP_OPEN		0x0100
60 #define LOOKUP_CREATE		0x0200
61 #define LOOKUP_EXCL		0x0400
62 #define LOOKUP_RENAME_TARGET	0x0800
63 
64 extern int user_path_at(int, const char __user *, unsigned, struct path *);
65 
66 #define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
67 #define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
68 #define user_path_dir(name, path) \
69 	user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
70 
71 extern int kern_path(const char *, unsigned, struct path *);
72 
73 extern int path_lookup(const char *, unsigned, struct nameidata *);
74 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
75 			   const char *, unsigned int, struct nameidata *);
76 
77 extern struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
78 		int (*open)(struct inode *, struct file *));
79 
80 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
81 
82 extern int follow_down(struct path *);
83 extern int follow_up(struct path *);
84 
85 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
86 extern void unlock_rename(struct dentry *, struct dentry *);
87 
88 static inline void nd_set_link(struct nameidata *nd, char *path)
89 {
90 	nd->saved_names[nd->depth] = path;
91 }
92 
93 static inline char *nd_get_link(struct nameidata *nd)
94 {
95 	return nd->saved_names[nd->depth];
96 }
97 
98 static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
99 {
100 	((char *) name)[min(len, maxlen)] = '\0';
101 }
102 
103 #endif /* _LINUX_NAMEI_H */
104