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       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                 :            : /* pathwalk mode */
      20                 :            : #define LOOKUP_FOLLOW           0x0001  /* follow links at the end */
      21                 :            : #define LOOKUP_DIRECTORY        0x0002  /* require a directory */
      22                 :            : #define LOOKUP_AUTOMOUNT        0x0004  /* force terminal automount */
      23                 :            : #define LOOKUP_EMPTY            0x4000  /* accept empty path [user_... only] */
      24                 :            : #define LOOKUP_DOWN             0x8000  /* follow mounts in the starting point */
      25                 :            : 
      26                 :            : #define LOOKUP_REVAL            0x0020  /* tell ->d_revalidate() to trust no cache */
      27                 :            : #define LOOKUP_RCU              0x0040  /* RCU pathwalk mode; semi-internal */
      28                 :            : 
      29                 :            : /* These tell filesystem methods that we are dealing with the final component... */
      30                 :            : #define LOOKUP_OPEN             0x0100  /* ... in open */
      31                 :            : #define LOOKUP_CREATE           0x0200  /* ... in object creation */
      32                 :            : #define LOOKUP_EXCL             0x0400  /* ... in exclusive creation */
      33                 :            : #define LOOKUP_RENAME_TARGET    0x0800  /* ... in destination of rename() */
      34                 :            : 
      35                 :            : /* internal use only */
      36                 :            : #define LOOKUP_PARENT           0x0010
      37                 :            : #define LOOKUP_NO_REVAL         0x0080
      38                 :            : #define LOOKUP_JUMPED           0x1000
      39                 :            : #define LOOKUP_ROOT             0x2000
      40                 :            : #define LOOKUP_ROOT_GRABBED     0x0008
      41                 :            : 
      42                 :            : extern int path_pts(struct path *path);
      43                 :            : 
      44                 :            : extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
      45                 :            : 
      46                 :            : static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
      47                 :            :                  struct path *path)
      48                 :            : {
      49                 :          3 :         return user_path_at_empty(dfd, name, flags, path, NULL);
      50                 :            : }
      51                 :            : 
      52                 :            : extern int kern_path(const char *, unsigned, struct path *);
      53                 :            : 
      54                 :            : extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
      55                 :            : extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
      56                 :            : extern void done_path_create(struct path *, struct dentry *);
      57                 :            : extern struct dentry *kern_path_locked(const char *, struct path *);
      58                 :            : extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
      59                 :            : 
      60                 :            : extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int);
      61                 :            : extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
      62                 :            : extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);
      63                 :            : 
      64                 :            : extern int follow_down_one(struct path *);
      65                 :            : extern int follow_down(struct path *);
      66                 :            : extern int follow_up(struct path *);
      67                 :            : 
      68                 :            : extern struct dentry *lock_rename(struct dentry *, struct dentry *);
      69                 :            : extern void unlock_rename(struct dentry *, struct dentry *);
      70                 :            : 
      71                 :            : extern void nd_jump_link(struct path *path);
      72                 :            : 
      73                 :            : static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
      74                 :            : {
      75                 :          3 :         ((char *) name)[min(len, maxlen)] = '\0';
      76                 :            : }
      77                 :            : 
      78                 :            : /**
      79                 :            :  * retry_estale - determine whether the caller should retry an operation
      80                 :            :  * @error: the error that would currently be returned
      81                 :            :  * @flags: flags being used for next lookup attempt
      82                 :            :  *
      83                 :            :  * Check to see if the error code was -ESTALE, and then determine whether
      84                 :            :  * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
      85                 :            :  *
      86                 :            :  * Returns true if the caller should try the operation again.
      87                 :            :  */
      88                 :            : static inline bool
      89                 :            : retry_estale(const long error, const unsigned int flags)
      90                 :            : {
      91                 :          3 :         return error == -ESTALE && !(flags & LOOKUP_REVAL);
      92                 :            : }
      93                 :            : 
      94                 :            : #endif /* _LINUX_NAMEI_H */