Line data    Source code

       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           0 :         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 mnt_idmap *, const char *, struct dentry *, int);
      72             : struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap,
      73             :                                    const char *name, struct dentry *base,
      74             :                                    int len);
      75             : struct dentry *lookup_one_positive_unlocked(struct mnt_idmap *idmap,
      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 *path, unsigned int flags);
      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           0 :         ((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           0 :         return error == -ESTALE && !(flags & LOOKUP_REVAL);
     107             : }
     108             : 
     109             : #endif /* _LINUX_NAMEI_H */