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, LAST_BIND}; 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 27 #define LOOKUP_REVAL 0x0020 /* tell ->d_revalidate() to trust no cache */ 28 #define LOOKUP_RCU 0x0040 /* RCU pathwalk mode; semi-internal */ 29 30 /* These tell filesystem methods that we are dealing with the final component... */ 31 #define LOOKUP_OPEN 0x0100 /* ... in open */ 32 #define LOOKUP_CREATE 0x0200 /* ... in object creation */ 33 #define LOOKUP_EXCL 0x0400 /* ... in exclusive creation */ 34 #define LOOKUP_RENAME_TARGET 0x0800 /* ... in destination of rename() */ 35 36 /* internal use only */ 37 #define LOOKUP_PARENT 0x0010 38 #define LOOKUP_JUMPED 0x1000 39 #define LOOKUP_ROOT 0x2000 40 #define LOOKUP_ROOT_GRABBED 0x0008 41 42 /* Scoping flags for lookup. */ 43 #define LOOKUP_NO_SYMLINKS 0x010000 /* No symlink crossing. */ 44 #define LOOKUP_NO_MAGICLINKS 0x020000 /* No nd_jump_link() crossing. */ 45 #define LOOKUP_NO_XDEV 0x040000 /* No mountpoint crossing. */ 46 #define LOOKUP_BENEATH 0x080000 /* No escaping from starting point. */ 47 #define LOOKUP_IN_ROOT 0x100000 /* Treat dirfd as fs root. */ 48 /* LOOKUP_* flags which do scope-related checks based on the dirfd. */ 49 #define LOOKUP_IS_SCOPED (LOOKUP_BENEATH | LOOKUP_IN_ROOT) 50 51 extern int path_pts(struct path *path); 52 53 extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty); 54 55 static 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 61 extern int kern_path(const char *, unsigned, struct path *); 62 63 extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int); 64 extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int); 65 extern void done_path_create(struct path *, struct dentry *); 66 extern struct dentry *kern_path_locked(const char *, struct path *); 67 extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int); 68 69 extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int); 70 extern struct dentry *lookup_one_len(const char *, struct dentry *, int); 71 extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int); 72 extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int); 73 74 extern int follow_down_one(struct path *); 75 extern int follow_down(struct path *); 76 extern int follow_up(struct path *); 77 78 extern struct dentry *lock_rename(struct dentry *, struct dentry *); 79 extern void unlock_rename(struct dentry *, struct dentry *); 80 81 extern int __must_check nd_jump_link(struct path *path); 82 83 static inline void nd_terminate_link(void *name, size_t len, size_t maxlen) 84 { 85 ((char *) name)[min(len, maxlen)] = '\0'; 86 } 87 88 /** 89 * retry_estale - determine whether the caller should retry an operation 90 * @error: the error that would currently be returned 91 * @flags: flags being used for next lookup attempt 92 * 93 * Check to see if the error code was -ESTALE, and then determine whether 94 * to retry the call based on whether "flags" already has LOOKUP_REVAL set. 95 * 96 * Returns true if the caller should try the operation again. 97 */ 98 static inline bool 99 retry_estale(const long error, const unsigned int flags) 100 { 101 return error == -ESTALE && !(flags & LOOKUP_REVAL); 102 } 103 104 #endif /* _LINUX_NAMEI_H */ 105