| 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 | extern int kern_path(const char *, unsigned, struct path *); |
| 61 | |
| 62 | extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int); |
| 63 | extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int); |
| 64 | extern void done_path_create(struct path *, struct dentry *); |
| 65 | extern struct dentry *kern_path_locked(const char *, struct path *); |
| 66 | |
| 67 | extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int); |
| 68 | extern struct dentry *lookup_one_len(const char *, struct dentry *, int); |
| 69 | extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int); |
| 70 | extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int); |
| 71 | struct dentry *lookup_one(struct user_namespace *, const char *, struct dentry *, int); |
| 72 | struct dentry *lookup_one_unlocked(struct user_namespace *mnt_userns, |
| 73 | const char *name, struct dentry *base, |
| 74 | int len); |
| 75 | struct dentry *lookup_one_positive_unlocked(struct user_namespace *mnt_userns, |
| 76 | const char *name, |
| 77 | struct dentry *base, int len); |
| 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 int __must_check nd_jump_link(const struct path *path); |
| 87 | |
| 88 | static inline void nd_terminate_link(void *name, size_t len, size_t maxlen) |
| 89 | { |
| 90 | ((char *) name)[min(len, maxlen)] = '\0'; |
| 91 | } |
| 92 | |
| 93 | /** |
| 94 | * retry_estale - determine whether the caller should retry an operation |
| 95 | * @error: the error that would currently be returned |
| 96 | * @flags: flags being used for next lookup attempt |
| 97 | * |
| 98 | * Check to see if the error code was -ESTALE, and then determine whether |
| 99 | * to retry the call based on whether "flags" already has LOOKUP_REVAL set. |
| 100 | * |
| 101 | * Returns true if the caller should try the operation again. |
| 102 | */ |
| 103 | static inline bool |
| 104 | retry_estale(const long error, const unsigned int flags) |
| 105 | { |
| 106 | return error == -ESTALE && !(flags & LOOKUP_REVAL); |
| 107 | } |
| 108 | |
| 109 | #endif /* _LINUX_NAMEI_H */ |