LXR linux/include/linux/namei.h

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