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 /* pathwalk mode */
20 #define LOOKUP_FOLLOW 0x0001 /* follow links at the end */
21 #define LOOKUP_DIRECTORY 0x0002 /* require a directory */
22 #define LOOKUP_AUTOMOUNT 0x0004 /* force terminal automount */
23 #define LOOKUP_EMPTY 0x4000 /* accept empty path [user_... only] */
24 #define LOOKUP_DOWN 0x8000 /* follow mounts in the starting point */
25
26 #define LOOKUP_REVAL 0x0020 /* tell ->d_revalidate() to trust no cache */
27 #define LOOKUP_RCU 0x0040 /* RCU pathwalk mode; semi-internal */
28
29 /* These tell filesystem methods that we are dealing with the final component... */
30 #define LOOKUP_OPEN 0x0100 /* ... in open */
31 #define LOOKUP_CREATE 0x0200 /* ... in object creation */
32 #define LOOKUP_EXCL 0x0400 /* ... in exclusive creation */
33 #define LOOKUP_RENAME_TARGET 0x0800 /* ... in destination of rename() */
34
35 /* internal use only */
36 #define LOOKUP_PARENT 0x0010
37 #define LOOKUP_NO_REVAL 0x0080
38 #define LOOKUP_JUMPED 0x1000
39 #define LOOKUP_ROOT 0x2000
40 #define LOOKUP_ROOT_GRABBED 0x0008
41
42 extern int path_pts(struct path *path);
43
44 extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
45
user_path_at(int dfd,const char __user * name,unsigned flags,struct path * path)46 static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
47 struct path *path)
48 {
49 return user_path_at_empty(dfd, name, flags, path, NULL);
50 }
51
52 extern int kern_path(const char *, unsigned, struct path *);
53
54 extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
55 extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
56 extern void done_path_create(struct path *, struct dentry *);
57 extern struct dentry *kern_path_locked(const char *, struct path *);
58 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
59 const char *, unsigned int, struct path *);
60 extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
61
62 extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int);
63 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
64 extern struct dentry *lookup_one_len2(const char *, struct vfsmount *mnt, struct dentry *, int);
65 extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);
66
67 extern int follow_down_one(struct path *);
68 extern int follow_down(struct path *);
69 extern int follow_up(struct path *);
70
71 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
72 extern void unlock_rename(struct dentry *, struct dentry *);
73
74 extern void nd_jump_link(struct path *path);
75
nd_terminate_link(void * name,size_t len,size_t maxlen)76 static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
77 {
78 ((char *) name)[min(len, maxlen)] = '\0';
79 }
80
81 /**
82 * retry_estale - determine whether the caller should retry an operation
83 * @error: the error that would currently be returned
84 * @flags: flags being used for next lookup attempt
85 *
86 * Check to see if the error code was -ESTALE, and then determine whether
87 * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
88 *
89 * Returns true if the caller should try the operation again.
90 */
91 static inline bool
retry_estale(const long error,const unsigned int flags)92 retry_estale(const long error, const unsigned int flags)
93 {
94 return error == -ESTALE && !(flags & LOOKUP_REVAL);
95 }
96
97 #endif /* _LINUX_NAMEI_H */
98