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}; |
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 | #define LOOKUP_MOUNTPOINT 0x0080 /* follow mounts in the end */ |
27 | |
28 | #define LOOKUP_REVAL 0x0020 /* tell ->d_revalidate() to trust no cache */ |
29 | #define LOOKUP_RCU 0x0040 /* RCU pathwalk mode; semi-internal */ |
30 | |
31 | /* These tell filesystem methods that we are dealing with the final component... */ |
32 | #define LOOKUP_OPEN 0x0100 /* ... in open */ |
33 | #define LOOKUP_CREATE 0x0200 /* ... in object creation */ |
34 | #define LOOKUP_EXCL 0x0400 /* ... in exclusive creation */ |
35 | #define LOOKUP_RENAME_TARGET 0x0800 /* ... in destination of rename() */ |
36 | |
37 | /* internal use only */ |
38 | #define LOOKUP_PARENT 0x0010 |
39 | |
40 | /* Scoping flags for lookup. */ |
41 | #define LOOKUP_NO_SYMLINKS 0x010000 /* No symlink crossing. */ |
42 | #define LOOKUP_NO_MAGICLINKS 0x020000 /* No nd_jump_link() crossing. */ |
43 | #define LOOKUP_NO_XDEV 0x040000 /* No mountpoint crossing. */ |
44 | #define LOOKUP_BENEATH 0x080000 /* No escaping from starting point. */ |
45 | #define LOOKUP_IN_ROOT 0x100000 /* Treat dirfd as fs root. */ |
46 | #define LOOKUP_CACHED 0x200000 /* Only do cached lookup */ |
47 | /* LOOKUP_* flags which do scope-related checks based on the dirfd. */ |
48 | #define LOOKUP_IS_SCOPED (LOOKUP_BENEATH | LOOKUP_IN_ROOT) |
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 | |
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 | |
60 | struct dentry *lookup_one_qstr_excl(const struct qstr *name, |
61 | struct dentry *base, |
62 | unsigned int flags); |
63 | extern int kern_path(const char *, unsigned, struct path *); |
64 | |
65 | extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int); |
66 | extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int); |
67 | extern void done_path_create(struct path *, struct dentry *); |
68 | extern struct dentry *kern_path_locked(const char *, struct path *); |
69 | int vfs_path_parent_lookup(struct filename *filename, unsigned int flags, |
70 | struct path *parent, struct qstr *last, int *type, |
71 | const struct path *root); |
72 | int vfs_path_lookup(struct dentry *, struct vfsmount *, const char *, |
73 | unsigned int, struct path *); |
74 | |
75 | extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int); |
76 | extern struct dentry *lookup_one_len(const char *, struct dentry *, int); |
77 | extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int); |
78 | extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int); |
79 | struct dentry *lookup_one(struct mnt_idmap *, const char *, struct dentry *, int); |
80 | struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap, |
81 | const char *name, struct dentry *base, |
82 | int len); |
83 | struct dentry *lookup_one_positive_unlocked(struct mnt_idmap *idmap, |
84 | const char *name, |
85 | struct dentry *base, int len); |
86 | |
87 | extern int follow_down_one(struct path *); |
88 | extern int follow_down(struct path *path, unsigned int flags); |
89 | extern int follow_up(struct path *); |
90 | |
91 | extern struct dentry *lock_rename(struct dentry *, struct dentry *); |
92 | extern struct dentry *lock_rename_child(struct dentry *, struct dentry *); |
93 | extern void unlock_rename(struct dentry *, struct dentry *); |
94 | |
95 | /** |
96 | * mode_strip_umask - handle vfs umask stripping |
97 | * @dir: parent directory of the new inode |
98 | * @mode: mode of the new inode to be created in @dir |
99 | * |
100 | * In most filesystems, umask stripping depends on whether or not the |
101 | * filesystem supports POSIX ACLs. If the filesystem doesn't support it umask |
102 | * stripping is done directly in here. If the filesystem does support POSIX |
103 | * ACLs umask stripping is deferred until the filesystem calls |
104 | * posix_acl_create(). |
105 | * |
106 | * Some filesystems (like NFSv4) also want to avoid umask stripping by the |
107 | * VFS, but don't support POSIX ACLs. Those filesystems can set SB_I_NOUMASK |
108 | * to get this effect without declaring that they support POSIX ACLs. |
109 | * |
110 | * Returns: mode |
111 | */ |
112 | static inline umode_t __must_check mode_strip_umask(const struct inode *dir, umode_t mode) |
113 | { |
114 | if (!IS_POSIXACL(dir) && !(dir->i_sb->s_iflags & SB_I_NOUMASK)) |
115 | mode &= ~current_umask(); |
116 | return mode; |
117 | } |
118 | |
119 | extern int __must_check nd_jump_link(const struct path *path); |
120 | |
121 | static inline void nd_terminate_link(void *name, size_t len, size_t maxlen) |
122 | { |
123 | ((char *) name)[min(len, maxlen)] = '\0'; |
124 | } |
125 | |
126 | /** |
127 | * retry_estale - determine whether the caller should retry an operation |
128 | * @error: the error that would currently be returned |
129 | * @flags: flags being used for next lookup attempt |
130 | * |
131 | * Check to see if the error code was -ESTALE, and then determine whether |
132 | * to retry the call based on whether "flags" already has LOOKUP_REVAL set. |
133 | * |
134 | * Returns true if the caller should try the operation again. |
135 | */ |
136 | static inline bool |
137 | retry_estale(const long error, const unsigned int flags) |
138 | { |
139 | return unlikely(error == -ESTALE && !(flags & LOOKUP_REVAL)); |
140 | } |
141 | |
142 | #endif /* _LINUX_NAMEI_H */ |
143 | |