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1 /* SPDX-License-Identifier: GPL-2.0 */
6 #include <linux/kernel.h>
7 #include <linux/path.h>
8 #include <linux/fcntl.h>
9 #include <linux/errno.h>
11 enum { MAX_NESTED_LINKS
= 8 };
13 #define MAXSYMLINKS 40
16 * Type of the last component on LOOKUP_PARENT
18 enum {LAST_NORM
, LAST_ROOT
, LAST_DOT
, LAST_DOTDOT
};
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 */
28 #define LOOKUP_REVAL 0x0020 /* tell ->d_revalidate() to trust no cache */
29 #define LOOKUP_RCU 0x0040 /* RCU pathwalk mode; semi-internal */
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() */
37 /* internal use only */
38 #define LOOKUP_PARENT 0x0010
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)
50 extern int path_pts(struct path
*path
);
52 extern int user_path_at_empty(int, const char __user
*, unsigned, struct path
*, int *empty
);
54 static inline int user_path_at(int dfd
, const char __user
*name
, unsigned flags
,
57 return user_path_at_empty(dfd
, name
, flags
, path
, NULL
);
60 extern int kern_path(const char *, unsigned, struct path
*);
62 extern struct dentry
*kern_path_create(int, const char *, struct path
*, unsigned int);
63 extern struct dentry
*user_path_create(int, const char __user
*, struct path
*, unsigned int);
64 extern void done_path_create(struct path
*, struct dentry
*);
65 extern struct dentry
*kern_path_locked(const char *, struct path
*);
67 extern struct dentry
*try_lookup_one_len(const char *, struct dentry
*, int);
68 extern struct dentry
*lookup_one_len(const char *, struct dentry
*, int);
69 extern struct dentry
*lookup_one_len_unlocked(const char *, struct dentry
*, int);
70 extern struct dentry
*lookup_positive_unlocked(const char *, struct dentry
*, int);
71 struct dentry
*lookup_one(struct user_namespace
*, const char *, struct dentry
*, int);
73 extern int follow_down_one(struct path
*);
74 extern int follow_down(struct path
*);
75 extern int follow_up(struct path
*);
77 extern struct dentry
*lock_rename(struct dentry
*, struct dentry
*);
78 extern void unlock_rename(struct dentry
*, struct dentry
*);
80 extern int __must_check
nd_jump_link(struct path
*path
);
82 static inline void nd_terminate_link(void *name
, size_t len
, size_t maxlen
)
84 ((char *) name
)[min(len
, maxlen
)] = '\0';
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
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.
95 * Returns true if the caller should try the operation again.
98 retry_estale(const long error
, const unsigned int flags
)
100 return error
== -ESTALE
&& !(flags
& LOOKUP_REVAL
);
103 #endif /* _LINUX_NAMEI_H */