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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 : :
11 : : enum { MAX_NESTED_LINKS = 8 };
12 : :
13 : : #define MAXSYMLINKS 40
14 : :
15 : : /*
16 : : * Type of the last component on LOOKUP_PARENT
17 : : */
18 : : enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
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 : :
27 : : #define LOOKUP_REVAL 0x0020 /* tell ->d_revalidate() to trust no cache */
28 : : #define LOOKUP_RCU 0x0040 /* RCU pathwalk mode; semi-internal */
29 : :
30 : : /* These tell filesystem methods that we are dealing with the final component... */
31 : : #define LOOKUP_OPEN 0x0100 /* ... in open */
32 : : #define LOOKUP_CREATE 0x0200 /* ... in object creation */
33 : : #define LOOKUP_EXCL 0x0400 /* ... in exclusive creation */
34 : : #define LOOKUP_RENAME_TARGET 0x0800 /* ... in destination of rename() */
35 : :
36 : : /* internal use only */
37 : : #define LOOKUP_PARENT 0x0010
38 : : #define LOOKUP_JUMPED 0x1000
39 : : #define LOOKUP_ROOT 0x2000
40 : : #define LOOKUP_ROOT_GRABBED 0x0008
41 : :
42 : : /* Scoping flags for lookup. */
43 : : #define LOOKUP_NO_SYMLINKS 0x010000 /* No symlink crossing. */
44 : : #define LOOKUP_NO_MAGICLINKS 0x020000 /* No nd_jump_link() crossing. */
45 : : #define LOOKUP_NO_XDEV 0x040000 /* No mountpoint crossing. */
46 : : #define LOOKUP_BENEATH 0x080000 /* No escaping from starting point. */
47 : : #define LOOKUP_IN_ROOT 0x100000 /* Treat dirfd as fs root. */
48 : : /* LOOKUP_* flags which do scope-related checks based on the dirfd. */
49 : : #define LOOKUP_IS_SCOPED (LOOKUP_BENEATH | LOOKUP_IN_ROOT)
50 : :
51 : : extern int path_pts(struct path *path);
52 : :
53 : : extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
54 : :
55 : 176626 : static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
56 : : struct path *path)
57 : : {
58 : 176626 : return user_path_at_empty(dfd, name, flags, path, NULL);
59 : : }
60 : :
61 : : extern int kern_path(const char *, unsigned, struct path *);
62 : :
63 : : extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
64 : : extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
65 : : extern void done_path_create(struct path *, struct dentry *);
66 : : extern struct dentry *kern_path_locked(const char *, struct path *);
67 : : extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
68 : :
69 : : extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int);
70 : : extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
71 : : extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);
72 : : extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int);
73 : :
74 : : extern int follow_down_one(struct path *);
75 : : extern int follow_down(struct path *);
76 : : extern int follow_up(struct path *);
77 : :
78 : : extern struct dentry *lock_rename(struct dentry *, struct dentry *);
79 : : extern void unlock_rename(struct dentry *, struct dentry *);
80 : :
81 : : extern int __must_check nd_jump_link(struct path *path);
82 : :
83 : 1651 : static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
84 : : {
85 : 1651 : ((char *) name)[min(len, maxlen)] = '\0';
86 : 1651 : }
87 : :
88 : : /**
89 : : * retry_estale - determine whether the caller should retry an operation
90 : : * @error: the error that would currently be returned
91 : : * @flags: flags being used for next lookup attempt
92 : : *
93 : : * Check to see if the error code was -ESTALE, and then determine whether
94 : : * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
95 : : *
96 : : * Returns true if the caller should try the operation again.
97 : : */
98 : : static inline bool
99 : 157419 : retry_estale(const long error, const unsigned int flags)
100 : : {
101 [ - + - - : 311796 : return error == -ESTALE && !(flags & LOOKUP_REVAL);
- + - + -
- - + - +
- - - + -
+ - - - +
- + - - -
+ - + - -
- + - + -
- - + ]
102 : : }
103 : :
104 : : #endif /* _LINUX_NAMEI_H */
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