1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_NAMEI_H
3#define _LINUX_NAMEI_H
4
5#include <linux/kernel.h>
6#include <linux/path.h>
7#include <linux/fcntl.h>
8#include <linux/errno.h>
9
10enum { MAX_NESTED_LINKS = 8 };
11
12#define MAXSYMLINKS 40
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 * - skip revalidation
28 * - don't fetch xattrs on audit_inode
29 */
30#define LOOKUP_FOLLOW 0x0001
31#define LOOKUP_DIRECTORY 0x0002
32#define LOOKUP_AUTOMOUNT 0x0004
33
34#define LOOKUP_PARENT 0x0010
35#define LOOKUP_REVAL 0x0020
36#define LOOKUP_RCU 0x0040
37#define LOOKUP_NO_REVAL 0x0080
38#define LOOKUP_NO_EVAL 0x0100
39
40/*
41 * Intent data
42 */
43#define LOOKUP_OPEN 0x0100
44#define LOOKUP_CREATE 0x0200
45#define LOOKUP_EXCL 0x0400
46#define LOOKUP_RENAME_TARGET 0x0800
47
48#define LOOKUP_JUMPED 0x1000
49#define LOOKUP_ROOT 0x2000
50#define LOOKUP_EMPTY 0x4000
51#define LOOKUP_DOWN 0x8000
52
53extern int path_pts(struct path *path);
54
55extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
56
57static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
58 struct path *path)
59{
60 return user_path_at_empty(dfd, name, flags, path, NULL);
61}
62
63static inline int user_path(const char __user *name, struct path *path)
64{
65 return user_path_at_empty(AT_FDCWD, name, LOOKUP_FOLLOW, path, NULL);
66}
67
68static inline int user_lpath(const char __user *name, struct path *path)
69{
70 return user_path_at_empty(AT_FDCWD, name, 0, path, NULL);
71}
72
73static inline int user_path_dir(const char __user *name, struct path *path)
74{
75 return user_path_at_empty(AT_FDCWD, name,
76 LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path, NULL);
77}
78
79extern int kern_path(const char *, unsigned, struct path *);
80
81extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
82extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
83extern void done_path_create(struct path *, struct dentry *);
84extern struct dentry *kern_path_locked(const char *, struct path *);
85extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
86
87extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int);
88extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
89extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);
90
91extern int follow_down_one(struct path *);
92extern int follow_down(struct path *);
93extern int follow_up(struct path *);
94
95extern struct dentry *lock_rename(struct dentry *, struct dentry *);
96extern void unlock_rename(struct dentry *, struct dentry *);
97
98extern void nd_jump_link(struct path *path);
99
100static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
101{
102 ((char *) name)[min(len, maxlen)] = '\0';
103}
104
105/**
106 * retry_estale - determine whether the caller should retry an operation
107 * @error: the error that would currently be returned
108 * @flags: flags being used for next lookup attempt
109 *
110 * Check to see if the error code was -ESTALE, and then determine whether
111 * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
112 *
113 * Returns true if the caller should try the operation again.
114 */
115static inline bool
116retry_estale(const long error, const unsigned int flags)
117{
118 return error == -ESTALE && !(flags & LOOKUP_REVAL);
119}
120
121#endif /* _LINUX_NAMEI_H */
122