1 #ifndef _LINUX_NAMEI_H
2 #define _LINUX_NAMEI_H
3
4 #include <linux/kernel.h>
5 #include <linux/path.h>
6 #include <linux/fcntl.h>
7 #include <linux/errno.h>
8
9 enum { MAX_NESTED_LINKS = 8 };
10
11 #define MAXSYMLINKS 40
12
13 /*
14 * Type of the last component on LOOKUP_PARENT
15 */
16 enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
17
18 /*
19 * The bitmask for a lookup event:
20 * - follow links at the end
21 * - require a directory
22 * - ending slashes ok even for nonexistent files
23 * - internal "there are more path components" flag
24 * - dentry cache is untrusted; force a real lookup
25 * - suppress terminal automount
26 */
27 #define LOOKUP_FOLLOW 0x0001
28 #define LOOKUP_DIRECTORY 0x0002
29 #define LOOKUP_AUTOMOUNT 0x0004
30
31 #define LOOKUP_PARENT 0x0010
32 #define LOOKUP_REVAL 0x0020
33 #define LOOKUP_RCU 0x0040
34
35 /*
36 * Intent data
37 */
38 #define LOOKUP_OPEN 0x0100
39 #define LOOKUP_CREATE 0x0200
40 #define LOOKUP_EXCL 0x0400
41 #define LOOKUP_RENAME_TARGET 0x0800
42
43 #define LOOKUP_JUMPED 0x1000
44 #define LOOKUP_ROOT 0x2000
45 #define LOOKUP_EMPTY 0x4000
46
47 extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
48
49 static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
50 struct path *path)
51 {
52 return user_path_at_empty(dfd, name, flags, path, NULL);
53 }
54
55 static inline int user_path(const char __user *name, struct path *path)
56 {
57 return user_path_at_empty(AT_FDCWD, name, LOOKUP_FOLLOW, path, NULL);
58 }
59
60 static inline int user_lpath(const char __user *name, struct path *path)
61 {
62 return user_path_at_empty(AT_FDCWD, name, 0, path, NULL);
63 }
64
65 static inline int user_path_dir(const char __user *name, struct path *path)
66 {
67 return user_path_at_empty(AT_FDCWD, name,
68 LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path, NULL);
69 }
70
71 extern int kern_path(const char *, unsigned, struct path *);
72
73 extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
74 extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
75 extern void done_path_create(struct path *, struct dentry *);
76 extern struct dentry *kern_path_locked(const char *, struct path *);
77 extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
78
79 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
80 extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);
81
82 extern int follow_down_one(struct path *);
83 extern int follow_down(struct path *);
84 extern int follow_up(struct path *);
85
86 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
87 extern void unlock_rename(struct dentry *, struct dentry *);
88
89 extern void nd_jump_link(struct path *path);
90
91 static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
92 {
93 ((char *) name)[min(len, maxlen)] = '\0';
94 }
95
96 /**
97 * retry_estale - determine whether the caller should retry an operation
98 * @error: the error that would currently be returned
99 * @flags: flags being used for next lookup attempt
100 *
101 * Check to see if the error code was -ESTALE, and then determine whether
102 * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
103 *
104 * Returns true if the caller should try the operation again.
105 */
106 static inline bool
107 retry_estale(const long error, const unsigned int flags)
108 {
109 return error == -ESTALE && !(flags & LOOKUP_REVAL);
110 }
111
112 #endif /* _LINUX_NAMEI_H */
113
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