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 */ 118