| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | #ifndef _LINUX_NAMEI_H |
| 3 | #define _LINUX_NAMEI_H |
| 4 | |
| 5 | #include <linux/kernel.h> |
| 6 | #include <linux/path.h> |
| 7 | #include <linux/fcntl.h> |
| 8 | #include <linux/errno.h> |
| 9 | |
| 10 | enum { MAX_NESTED_LINKS = 8 }; |
| 11 | |
| 12 | #define MAXSYMLINKS 40 |
| 13 | |
| 14 | /* |
| 15 | * Type of the last component on LOOKUP_PARENT |
| 16 | */ |
| 17 | enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND}; |
| 18 | |
| 19 | /* |
| 20 | * The bitmask for a lookup event: |
| 21 | * - follow links at the end |
| 22 | * - require a directory |
| 23 | * - ending slashes ok even for nonexistent files |
| 24 | * - internal "there are more path components" flag |
| 25 | * - dentry cache is untrusted; force a real lookup |
| 26 | * - suppress terminal automount |
| 27 | */ |
| 28 | #define LOOKUP_FOLLOW 0x0001 |
| 29 | #define LOOKUP_DIRECTORY 0x0002 |
| 30 | #define LOOKUP_AUTOMOUNT 0x0004 |
| 31 | |
| 32 | #define LOOKUP_PARENT 0x0010 |
| 33 | #define LOOKUP_REVAL 0x0020 |
| 34 | #define LOOKUP_RCU 0x0040 |
| 35 | #define LOOKUP_NO_REVAL 0x0080 |
| 36 | |
| 37 | /* |
| 38 | * Intent data |
| 39 | */ |
| 40 | #define LOOKUP_OPEN 0x0100 |
| 41 | #define LOOKUP_CREATE 0x0200 |
| 42 | #define LOOKUP_EXCL 0x0400 |
| 43 | #define LOOKUP_RENAME_TARGET 0x0800 |
| 44 | |
| 45 | #define LOOKUP_JUMPED 0x1000 |
| 46 | #define LOOKUP_ROOT 0x2000 |
| 47 | #define LOOKUP_EMPTY 0x4000 |
| 48 | #define LOOKUP_DOWN 0x8000 |
| 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 | static inline int user_path(const char __user *name, struct path *path) |
| 61 | { |
| 62 | return user_path_at_empty(AT_FDCWD, name, LOOKUP_FOLLOW, path, NULL); |
| 63 | } |
| 64 | |
| 65 | static inline int user_lpath(const char __user *name, struct path *path) |
| 66 | { |
| 67 | return user_path_at_empty(AT_FDCWD, name, 0, path, NULL); |
| 68 | } |
| 69 | |
| 70 | static inline int user_path_dir(const char __user *name, struct path *path) |
| 71 | { |
| 72 | return user_path_at_empty(AT_FDCWD, name, |
| 73 | LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path, NULL); |
| 74 | } |
| 75 | |
| 76 | extern int kern_path(const char *, unsigned, struct path *); |
| 77 | |
| 78 | extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int); |
| 79 | extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int); |
| 80 | extern void done_path_create(struct path *, struct dentry *); |
| 81 | extern struct dentry *kern_path_locked(const char *, struct path *); |
| 82 | extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int); |
| 83 | |
| 84 | extern struct dentry *lookup_one_len(const char *, struct dentry *, int); |
| 85 | extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int); |
| 86 | |
| 87 | extern int follow_down_one(struct path *); |
| 88 | extern int follow_down(struct path *); |
| 89 | extern int follow_up(struct path *); |
| 90 | |
| 91 | extern struct dentry *lock_rename(struct dentry *, struct dentry *); |
| 92 | extern void unlock_rename(struct dentry *, struct dentry *); |
| 93 | |
| 94 | extern void nd_jump_link(struct path *path); |
| 95 | |
| 96 | static inline void nd_terminate_link(void *name, size_t len, size_t maxlen) |
| 97 | { |
| 98 | ((char *) name)[min(len, maxlen)] = '\0'; |
| 99 | } |
| 100 | |
| 101 | /** |
| 102 | * retry_estale - determine whether the caller should retry an operation |
| 103 | * @error: the error that would currently be returned |
| 104 | * @flags: flags being used for next lookup attempt |
| 105 | * |
| 106 | * Check to see if the error code was -ESTALE, and then determine whether |
| 107 | * to retry the call based on whether "flags" already has LOOKUP_REVAL set. |
| 108 | * |
| 109 | * Returns true if the caller should try the operation again. |
| 110 | */ |
| 111 | static inline bool |
| 112 | retry_estale(const long error, const unsigned int flags) |
| 113 | { |
| 114 | return error == -ESTALE && !(flags & LOOKUP_REVAL); |
| 115 | } |
| 116 | |
| 117 | #endif /* _LINUX_NAMEI_H */ |