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 * - skip revalidation 28 * - don't fetch xattrs on audit_inode 29 */ 30 #define LOOKUP_FOLLOW 0x0001 31 #define LOOKUP_DIRECTORY 0x0002 32 #define LOOKUP_AUTOMOUNT 0x0004 33 34 #define LOOKUP_PARENT 0x0010 35 #define LOOKUP_REVAL 0x0020 36 #define LOOKUP_RCU 0x0040 37 #define LOOKUP_NO_REVAL 0x0080 38 #define LOOKUP_NO_EVAL 0x0100 39 40 /* 41 * Intent data 42 */ 43 #define LOOKUP_OPEN 0x0100 44 #define LOOKUP_CREATE 0x0200 45 #define LOOKUP_EXCL 0x0400 46 #define LOOKUP_RENAME_TARGET 0x0800 47 48 #define LOOKUP_JUMPED 0x1000 49 #define LOOKUP_ROOT 0x2000 50 #define LOOKUP_EMPTY 0x4000 51 #define LOOKUP_DOWN 0x8000 52 53 extern int path_pts(struct path *path); 54 55 extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty); 56 57 static inline int user_path_at(int dfd, const char __user *name, unsigned flags, 58 struct path *path) 59 { 60 return user_path_at_empty(dfd, name, flags, path, NULL); 61 } 62 63 static inline int user_path(const char __user *name, struct path *path) 64 { 65 return user_path_at_empty(AT_FDCWD, name, LOOKUP_FOLLOW, path, NULL); 66 } 67 68 static inline int user_lpath(const char __user *name, struct path *path) 69 { 70 return user_path_at_empty(AT_FDCWD, name, 0, path, NULL); 71 } 72 73 static inline int user_path_dir(const char __user *name, struct path *path) 74 { 75 return user_path_at_empty(AT_FDCWD, name, 76 LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path, NULL); 77 } 78 79 extern int kern_path(const char *, unsigned, struct path *); 80 81 extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int); 82 extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int); 83 extern void done_path_create(struct path *, struct dentry *); 84 extern struct dentry *kern_path_locked(const char *, struct path *); 85 extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int); 86 87 extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int); 88 extern struct dentry *lookup_one_len(const char *, struct dentry *, int); 89 extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int); 90 91 extern int follow_down_one(struct path *); 92 extern int follow_down(struct path *); 93 extern int follow_up(struct path *); 94 95 extern struct dentry *lock_rename(struct dentry *, struct dentry *); 96 extern void unlock_rename(struct dentry *, struct dentry *); 97 98 extern void nd_jump_link(struct path *path); 99 100 static inline void nd_terminate_link(void *name, size_t len, size_t maxlen) 101 { 102 ((char *) name)[min(len, maxlen)] = '\0'; 103 } 104 105 /** 106 * retry_estale - determine whether the caller should retry an operation 107 * @error: the error that would currently be returned 108 * @flags: flags being used for next lookup attempt 109 * 110 * Check to see if the error code was -ESTALE, and then determine whether 111 * to retry the call based on whether "flags" already has LOOKUP_REVAL set. 112 * 113 * Returns true if the caller should try the operation again. 114 */ 115 static inline bool 116 retry_estale(const long error, const unsigned int flags) 117 { 118 return error == -ESTALE && !(flags & LOOKUP_REVAL); 119 } 120 121 #endif /* _LINUX_NAMEI_H */ 122