Linux kernel mirror (for testing)
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linux
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
11enum { MAX_NESTED_LINKS = 8 };
12
13#define MAXSYMLINKS 40
14
15/*
16 * Type of the last component on LOOKUP_PARENT
17 */
18enum {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#define LOOKUP_LINKAT_EMPTY 0x400000 /* Linkat request with empty path. */
48/* LOOKUP_* flags which do scope-related checks based on the dirfd. */
49#define LOOKUP_IS_SCOPED (LOOKUP_BENEATH | LOOKUP_IN_ROOT)
50
51extern int path_pts(struct path *path);
52
53extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
54
55static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
56 struct path *path)
57{
58 return user_path_at_empty(dfd, name, flags, path, NULL);
59}
60
61struct dentry *lookup_one_qstr_excl(const struct qstr *name,
62 struct dentry *base,
63 unsigned int flags);
64extern int kern_path(const char *, unsigned, struct path *);
65
66extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
67extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
68extern void done_path_create(struct path *, struct dentry *);
69extern struct dentry *kern_path_locked(const char *, struct path *);
70extern struct dentry *user_path_locked_at(int , const char __user *, struct path *);
71int vfs_path_parent_lookup(struct filename *filename, unsigned int flags,
72 struct path *parent, struct qstr *last, int *type,
73 const struct path *root);
74int vfs_path_lookup(struct dentry *, struct vfsmount *, const char *,
75 unsigned int, struct path *);
76
77extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int);
78extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
79extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);
80extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int);
81struct dentry *lookup_one(struct mnt_idmap *, const char *, struct dentry *, int);
82struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap,
83 const char *name, struct dentry *base,
84 int len);
85struct dentry *lookup_one_positive_unlocked(struct mnt_idmap *idmap,
86 const char *name,
87 struct dentry *base, int len);
88
89extern int follow_down_one(struct path *);
90extern int follow_down(struct path *path, unsigned int flags);
91extern int follow_up(struct path *);
92
93extern struct dentry *lock_rename(struct dentry *, struct dentry *);
94extern struct dentry *lock_rename_child(struct dentry *, struct dentry *);
95extern void unlock_rename(struct dentry *, struct dentry *);
96
97/**
98 * mode_strip_umask - handle vfs umask stripping
99 * @dir: parent directory of the new inode
100 * @mode: mode of the new inode to be created in @dir
101 *
102 * In most filesystems, umask stripping depends on whether or not the
103 * filesystem supports POSIX ACLs. If the filesystem doesn't support it umask
104 * stripping is done directly in here. If the filesystem does support POSIX
105 * ACLs umask stripping is deferred until the filesystem calls
106 * posix_acl_create().
107 *
108 * Some filesystems (like NFSv4) also want to avoid umask stripping by the
109 * VFS, but don't support POSIX ACLs. Those filesystems can set SB_I_NOUMASK
110 * to get this effect without declaring that they support POSIX ACLs.
111 *
112 * Returns: mode
113 */
114static inline umode_t __must_check mode_strip_umask(const struct inode *dir, umode_t mode)
115{
116 if (!IS_POSIXACL(dir) && !(dir->i_sb->s_iflags & SB_I_NOUMASK))
117 mode &= ~current_umask();
118 return mode;
119}
120
121extern int __must_check nd_jump_link(const struct path *path);
122
123static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
124{
125 ((char *) name)[min(len, maxlen)] = '\0';
126}
127
128/**
129 * retry_estale - determine whether the caller should retry an operation
130 * @error: the error that would currently be returned
131 * @flags: flags being used for next lookup attempt
132 *
133 * Check to see if the error code was -ESTALE, and then determine whether
134 * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
135 *
136 * Returns true if the caller should try the operation again.
137 */
138static inline bool
139retry_estale(const long error, const unsigned int flags)
140{
141 return unlikely(error == -ESTALE && !(flags & LOOKUP_REVAL));
142}
143
144#endif /* _LINUX_NAMEI_H */