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 */ 110