Linux kernel mirror (for testing)
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linux
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_NAMEI_H
3#define _LINUX_NAMEI_H
4
5#include <linux/fs.h>
6#include <linux/kernel.h>
7#include <linux/path.h>
8#include <linux/fcntl.h>
9#include <linux/errno.h>
10
11enum { MAX_NESTED_LINKS = 8 };
12
13#define MAXSYMLINKS 40
14
15/*
16 * Type of the last component on LOOKUP_PARENT
17 */
18enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT};
19
20/* pathwalk mode */
21#define LOOKUP_FOLLOW 0x0001 /* follow links at the end */
22#define LOOKUP_DIRECTORY 0x0002 /* require a directory */
23#define LOOKUP_AUTOMOUNT 0x0004 /* force terminal automount */
24#define LOOKUP_EMPTY 0x4000 /* accept empty path [user_... only] */
25#define LOOKUP_DOWN 0x8000 /* follow mounts in the starting point */
26#define LOOKUP_MOUNTPOINT 0x0080 /* follow mounts in the end */
27
28#define LOOKUP_REVAL 0x0020 /* tell ->d_revalidate() to trust no cache */
29#define LOOKUP_RCU 0x0040 /* RCU pathwalk mode; semi-internal */
30
31/* These tell filesystem methods that we are dealing with the final component... */
32#define LOOKUP_OPEN 0x0100 /* ... in open */
33#define LOOKUP_CREATE 0x0200 /* ... in object creation */
34#define LOOKUP_EXCL 0x0400 /* ... in exclusive creation */
35#define LOOKUP_RENAME_TARGET 0x0800 /* ... in destination of rename() */
36
37/* internal use only */
38#define LOOKUP_PARENT 0x0010
39
40/* Scoping flags for lookup. */
41#define LOOKUP_NO_SYMLINKS 0x010000 /* No symlink crossing. */
42#define LOOKUP_NO_MAGICLINKS 0x020000 /* No nd_jump_link() crossing. */
43#define LOOKUP_NO_XDEV 0x040000 /* No mountpoint crossing. */
44#define LOOKUP_BENEATH 0x080000 /* No escaping from starting point. */
45#define LOOKUP_IN_ROOT 0x100000 /* Treat dirfd as fs root. */
46#define LOOKUP_CACHED 0x200000 /* Only do cached lookup */
47/* LOOKUP_* flags which do scope-related checks based on the dirfd. */
48#define LOOKUP_IS_SCOPED (LOOKUP_BENEATH | LOOKUP_IN_ROOT)
49
50extern int path_pts(struct path *path);
51
52extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
53
54static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
55 struct path *path)
56{
57 return user_path_at_empty(dfd, name, flags, path, NULL);
58}
59
60extern int kern_path(const char *, unsigned, struct path *);
61
62extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
63extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
64extern void done_path_create(struct path *, struct dentry *);
65extern struct dentry *kern_path_locked(const char *, struct path *);
66
67extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int);
68extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
69extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);
70extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int);
71struct dentry *lookup_one(struct user_namespace *, const char *, struct dentry *, int);
72
73extern int follow_down_one(struct path *);
74extern int follow_down(struct path *);
75extern int follow_up(struct path *);
76
77extern struct dentry *lock_rename(struct dentry *, struct dentry *);
78extern void unlock_rename(struct dentry *, struct dentry *);
79
80extern int __must_check nd_jump_link(struct path *path);
81
82static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
83{
84 ((char *) name)[min(len, maxlen)] = '\0';
85}
86
87/**
88 * retry_estale - determine whether the caller should retry an operation
89 * @error: the error that would currently be returned
90 * @flags: flags being used for next lookup attempt
91 *
92 * Check to see if the error code was -ESTALE, and then determine whether
93 * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
94 *
95 * Returns true if the caller should try the operation again.
96 */
97static inline bool
98retry_estale(const long error, const unsigned int flags)
99{
100 return error == -ESTALE && !(flags & LOOKUP_REVAL);
101}
102
103#endif /* _LINUX_NAMEI_H */