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