1#ifndef _LINUX_NAMEI_H
2#define _LINUX_NAMEI_H
3
4#include <linux/dcache.h>
5#include <linux/errno.h>
6#include <linux/linkage.h>
7#include <linux/path.h>
8
9struct vfsmount;
10struct nameidata;
11
12enum { MAX_NESTED_LINKS = 8 };
13
14/*
15 * Type of the last component on LOOKUP_PARENT
16 */
17enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
18
19/*
20 * The bitmask for a lookup event:
21 *  - follow links at the end
22 *  - require a directory
23 *  - ending slashes ok even for nonexistent files
24 *  - internal "there are more path components" flag
25 *  - dentry cache is untrusted; force a real lookup
26 *  - suppress terminal automount
27 */
28#define LOOKUP_FOLLOW		0x0001
29#define LOOKUP_DIRECTORY	0x0002
30#define LOOKUP_AUTOMOUNT	0x0004
31
32#define LOOKUP_PARENT		0x0010
33#define LOOKUP_REVAL		0x0020
34#define LOOKUP_RCU		0x0040
35
36/*
37 * Intent data
38 */
39#define LOOKUP_OPEN		0x0100
40#define LOOKUP_CREATE		0x0200
41#define LOOKUP_EXCL		0x0400
42#define LOOKUP_RENAME_TARGET	0x0800
43
44#define LOOKUP_JUMPED		0x1000
45#define LOOKUP_ROOT		0x2000
46#define LOOKUP_EMPTY		0x4000
47
48extern int user_path_at(int, const char __user *, unsigned, struct path *);
49extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
50
51#define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
52#define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
53#define user_path_dir(name, path) \
54	user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
55
56extern int kern_path(const char *, unsigned, struct path *);
57
58extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
59extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
60extern void done_path_create(struct path *, struct dentry *);
61extern struct dentry *kern_path_locked(const char *, struct path *);
62extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
63
64extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
65
66extern int follow_down_one(struct path *);
67extern int follow_down(struct path *);
68extern int follow_up(struct path *);
69
70extern struct dentry *lock_rename(struct dentry *, struct dentry *);
71extern void unlock_rename(struct dentry *, struct dentry *);
72
73extern void nd_jump_link(struct nameidata *nd, struct path *path);
74extern void nd_set_link(struct nameidata *nd, char *path);
75extern char *nd_get_link(struct nameidata *nd);
76
77static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
78{
79	((char *) name)[min(len, maxlen)] = '\0';
80}
81
82/**
83 * retry_estale - determine whether the caller should retry an operation
84 * @error: the error that would currently be returned
85 * @flags: flags being used for next lookup attempt
86 *
87 * Check to see if the error code was -ESTALE, and then determine whether
88 * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
89 *
90 * Returns true if the caller should try the operation again.
91 */
92static inline bool
93retry_estale(const long error, const unsigned int flags)
94{
95	return error == -ESTALE && !(flags & LOOKUP_REVAL);
96}
97
98#endif /* _LINUX_NAMEI_H */
99