xref: /linux-6.15/include/linux/namei.h (revision 6fa79bca)
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 enum { MAX_NESTED_LINKS = 8 };
11 
12 struct nameidata {
13 	struct path	path;
14 	struct qstr	last;
15 	struct path	root;
16 	struct inode	*inode; /* path.dentry.d_inode */
17 	unsigned int	flags;
18 	unsigned	seq;
19 	int		last_type;
20 	unsigned	depth;
21 	char *saved_names[MAX_NESTED_LINKS + 1];
22 };
23 
24 /*
25  * Type of the last component on LOOKUP_PARENT
26  */
27 enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
28 
29 /*
30  * The bitmask for a lookup event:
31  *  - follow links at the end
32  *  - require a directory
33  *  - ending slashes ok even for nonexistent files
34  *  - internal "there are more path components" flag
35  *  - dentry cache is untrusted; force a real lookup
36  *  - suppress terminal automount
37  */
38 #define LOOKUP_FOLLOW		0x0001
39 #define LOOKUP_DIRECTORY	0x0002
40 #define LOOKUP_AUTOMOUNT	0x0004
41 
42 #define LOOKUP_PARENT		0x0010
43 #define LOOKUP_REVAL		0x0020
44 #define LOOKUP_RCU		0x0040
45 
46 /*
47  * Intent data
48  */
49 #define LOOKUP_OPEN		0x0100
50 #define LOOKUP_CREATE		0x0200
51 #define LOOKUP_EXCL		0x0400
52 #define LOOKUP_RENAME_TARGET	0x0800
53 
54 #define LOOKUP_JUMPED		0x1000
55 #define LOOKUP_ROOT		0x2000
56 #define LOOKUP_EMPTY		0x4000
57 
58 extern int user_path_at(int, const char __user *, unsigned, struct path *);
59 extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
60 
61 #define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
62 #define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
63 #define user_path_dir(name, path) \
64 	user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
65 
66 extern int kern_path(const char *, unsigned, struct path *);
67 
68 extern struct dentry *kern_path_create(int, const char *, struct path *, int);
69 extern struct dentry *user_path_create(int, const char __user *, struct path *, int);
70 extern void done_path_create(struct path *, struct dentry *);
71 extern struct dentry *kern_path_locked(const char *, struct path *);
72 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
73 			   const char *, unsigned int, struct path *);
74 
75 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
76 
77 extern int follow_down_one(struct path *);
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 extern void nd_jump_link(struct nameidata *nd, struct path *path);
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 static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
97 {
98 	((char *) name)[min(len, maxlen)] = '\0';
99 }
100 
101 #endif /* _LINUX_NAMEI_H */
102