linux/include/linux/namei.h
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   1#ifndef _LINUX_NAMEI_H
   2#define _LINUX_NAMEI_H
   3
   4#include <linux/dcache.h>
   5#include <linux/errno.h>
   6#include <linux/linkage.h>
   7#include <linux/path.h>
   8
   9struct vfsmount;
  10
  11enum { MAX_NESTED_LINKS = 8 };
  12
  13struct nameidata {
  14        struct path     path;
  15        struct qstr     last;
  16        struct path     root;
  17        struct inode    *inode; /* path.dentry.d_inode */
  18        unsigned int    flags;
  19        unsigned        seq;
  20        int             last_type;
  21        unsigned        depth;
  22        char *saved_names[MAX_NESTED_LINKS + 1];
  23};
  24
  25/*
  26 * Type of the last component on LOOKUP_PARENT
  27 */
  28enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
  29
  30/*
  31 * The bitmask for a lookup event:
  32 *  - follow links at the end
  33 *  - require a directory
  34 *  - ending slashes ok even for nonexistent files
  35 *  - internal "there are more path components" flag
  36 *  - dentry cache is untrusted; force a real lookup
  37 *  - suppress terminal automount
  38 */
  39#define LOOKUP_FOLLOW           0x0001
  40#define LOOKUP_DIRECTORY        0x0002
  41#define LOOKUP_AUTOMOUNT        0x0004
  42
  43#define LOOKUP_PARENT           0x0010
  44#define LOOKUP_REVAL            0x0020
  45#define LOOKUP_RCU              0x0040
  46
  47/*
  48 * Intent data
  49 */
  50#define LOOKUP_OPEN             0x0100
  51#define LOOKUP_CREATE           0x0200
  52#define LOOKUP_EXCL             0x0400
  53#define LOOKUP_RENAME_TARGET    0x0800
  54
  55#define LOOKUP_JUMPED           0x1000
  56#define LOOKUP_ROOT             0x2000
  57#define LOOKUP_EMPTY            0x4000
  58
  59extern int user_path_at(int, const char __user *, unsigned, struct path *);
  60extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
  61
  62#define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
  63#define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
  64#define user_path_dir(name, path) \
  65        user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
  66
  67extern int kern_path(const char *, unsigned, struct path *);
  68
  69extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
  70extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
  71extern void done_path_create(struct path *, struct dentry *);
  72extern struct dentry *kern_path_locked(const char *, struct path *);
  73extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
  74                           const char *, unsigned int, struct path *);
  75
  76extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
  77
  78extern int follow_down_one(struct path *);
  79extern int follow_down(struct path *);
  80extern int follow_up(struct path *);
  81
  82extern struct dentry *lock_rename(struct dentry *, struct dentry *);
  83extern void unlock_rename(struct dentry *, struct dentry *);
  84
  85extern void nd_jump_link(struct nameidata *nd, struct path *path);
  86
  87static inline void nd_set_link(struct nameidata *nd, char *path)
  88{
  89        nd->saved_names[nd->depth] = path;
  90}
  91
  92static inline char *nd_get_link(struct nameidata *nd)
  93{
  94        return nd->saved_names[nd->depth];
  95}
  96
  97static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
  98{
  99        ((char *) name)[min(len, maxlen)] = '\0';
 100}
 101
 102/**
 103 * retry_estale - determine whether the caller should retry an operation
 104 * @error: the error that would currently be returned
 105 * @flags: flags being used for next lookup attempt
 106 *
 107 * Check to see if the error code was -ESTALE, and then determine whether
 108 * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
 109 *
 110 * Returns true if the caller should try the operation again.
 111 */
 112static inline bool
 113retry_estale(const long error, const unsigned int flags)
 114{
 115        return error == -ESTALE && !(flags & LOOKUP_REVAL);
 116}
 117
 118#endif /* _LINUX_NAMEI_H */
 119
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