1 #ifndef _LINUX_NAMEI_H
2 #define _LINUX_NAMEI_H
3
4 #include <linux/dcache.h>
5 #include <linux/errno.h>
6 #include <linux/linkage.h>
7 #include <linux/path.h>
8
9 struct vfsmount;
10
11 enum { MAX_NESTED_LINKS = 8 };
12
13 struct nameidata {
14 struct path path;
15 struct qstr last;
16 struct path root;
17 struct inode *inode; /* path.dentry.d_inode */
18 unsigned int flags;
19 unsigned seq;
20 int last_type;
21 unsigned depth;
22 char *saved_names[MAX_NESTED_LINKS + 1];
23 };
24
25 /*
26 * Type of the last component on LOOKUP_PARENT
27 */
28 enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
29
30 /*
31 * The bitmask for a lookup event:
32 * - follow links at the end
33 * - require a directory
34 * - ending slashes ok even for nonexistent files
35 * - internal "there are more path components" flag
36 * - dentry cache is untrusted; force a real lookup
37 * - suppress terminal automount
38 */
39 #define LOOKUP_FOLLOW 0x0001
40 #define LOOKUP_DIRECTORY 0x0002
41 #define LOOKUP_AUTOMOUNT 0x0004
42
43 #define LOOKUP_PARENT 0x0010
44 #define LOOKUP_REVAL 0x0020
45 #define LOOKUP_RCU 0x0040
46
47 /*
48 * Intent data
49 */
50 #define LOOKUP_OPEN 0x0100
51 #define LOOKUP_CREATE 0x0200
52 #define LOOKUP_EXCL 0x0400
53 #define LOOKUP_RENAME_TARGET 0x0800
54
55 #define LOOKUP_JUMPED 0x1000
56 #define LOOKUP_ROOT 0x2000
57 #define LOOKUP_EMPTY 0x4000
58
59 extern int user_path_at(int, const char __user *, unsigned, struct path *);
60 extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
61
62 #define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
63 #define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
64 #define user_path_dir(name, path) \
65 user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
66
67 extern int kern_path(const char *, unsigned, struct path *);
68
69 extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
70 extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
71 extern void done_path_create(struct path *, struct dentry *);
72 extern struct dentry *kern_path_locked(const char *, struct path *);
73 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
74 const char *, unsigned int, struct path *);
75
76 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
77 extern struct dentry *lookup_one_len2(const char *, struct vfsmount *mnt, struct dentry *, int);
78
79 extern int follow_down_one(struct path *);
80 extern int follow_down(struct path *);
81 extern int follow_up(struct path *);
82
83 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
84 extern void unlock_rename(struct dentry *, struct dentry *);
85
86 extern void nd_jump_link(struct nameidata *nd, struct path *path);
87
nd_set_link(struct nameidata * nd,char * path)88 static inline void nd_set_link(struct nameidata *nd, char *path)
89 {
90 nd->saved_names[nd->depth] = path;
91 }
92
nd_get_link(struct nameidata * nd)93 static inline char *nd_get_link(struct nameidata *nd)
94 {
95 return nd->saved_names[nd->depth];
96 }
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