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
10 enum { MAX_NESTED_LINKS = 8 };
11
12 #define MAXSYMLINKS 40
13
14 /*
15 * Type of the last component on LOOKUP_PARENT
16 */
17 enum {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 */
28 #define LOOKUP_FOLLOW 0x0001
29 #define LOOKUP_DIRECTORY 0x0002
30 #define LOOKUP_AUTOMOUNT 0x0004
31
32 #define LOOKUP_PARENT 0x0010
33 #define LOOKUP_REVAL 0x0020
34 #define LOOKUP_RCU 0x0040
35 #define LOOKUP_NO_REVAL 0x0080
36
37 /*
38 * Intent data
39 */
40 #define LOOKUP_OPEN 0x0100
41 #define LOOKUP_CREATE 0x0200
42 #define LOOKUP_EXCL 0x0400
43 #define LOOKUP_RENAME_TARGET 0x0800
44
45 #define LOOKUP_JUMPED 0x1000
46 #define LOOKUP_ROOT 0x2000
47 #define LOOKUP_EMPTY 0x4000
48 #define LOOKUP_DOWN 0x8000
49
50 extern int path_pts(struct path *path);
51
52 extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
53
user_path_at(int dfd,const char __user * name,unsigned flags,struct path * path)54 static 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
user_path(const char __user * name,struct path * path)60 static inline int user_path(const char __user *name, struct path *path)
61 {
62 return user_path_at_empty(AT_FDCWD, name, LOOKUP_FOLLOW, path, NULL);
63 }
64
user_lpath(const char __user * name,struct path * path)65 static inline int user_lpath(const char __user *name, struct path *path)
66 {
67 return user_path_at_empty(AT_FDCWD, name, 0, path, NULL);
68 }
69
user_path_dir(const char __user * name,struct path * path)70 static inline int user_path_dir(const char __user *name, struct path *path)
71 {
72 return user_path_at_empty(AT_FDCWD, name,
73 LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path, NULL);
74 }
75
76 extern int kern_path(const char *, unsigned, struct path *);
77
78 extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
79 extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
80 extern void done_path_create(struct path *, struct dentry *);
81 extern struct dentry *kern_path_locked(const char *, struct path *);
82 extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
83
84 extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int);
85 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
86 extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);
87 extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int);
88
89 extern int follow_down_one(struct path *);
90 extern int follow_down(struct path *);
91 extern int follow_up(struct path *);
92
93 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
94 extern void unlock_rename(struct dentry *, struct dentry *);
95
96 extern void nd_jump_link(struct path *path);
97
nd_terminate_link(void * name,size_t len,size_t maxlen)98 static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
99 {
100 ((char *) name)[min(len, maxlen)] = '\0';
101 }
102
103 /**
104 * retry_estale - determine whether the caller should retry an operation
105 * @error: the error that would currently be returned
106 * @flags: flags being used for next lookup attempt
107 *
108 * Check to see if the error code was -ESTALE, and then determine whether
109 * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
110 *
111 * Returns true if the caller should try the operation again.
112 */
113 static inline bool
retry_estale(const long error,const unsigned int flags)114 retry_estale(const long error, const unsigned int flags)
115 {
116 return error == -ESTALE && !(flags & LOOKUP_REVAL);
117 }
118
119 #endif /* _LINUX_NAMEI_H */
120