/* SPDX-License-Identifier: GPL-2.0 */

  #ifndef _LINUX_NAMEI_H
  #define _LINUX_NAMEI_H

  #include <linux/fs.h>

  #include <linux/kernel.h>

  #include <linux/path.h>

  #include <linux/fcntl.h>
  #include <linux/errno.h>

  enum { MAX_NESTED_LINKS = 8 };

  #define MAXSYMLINKS 40

  /*
   * Type of the last component on LOOKUP_PARENT
   */

  enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT};

  /* pathwalk mode */
  #define LOOKUP_FOLLOW		0x0001	/* follow links at the end */
  #define LOOKUP_DIRECTORY	0x0002	/* require a directory */
  #define LOOKUP_AUTOMOUNT	0x0004  /* force terminal automount */
  #define LOOKUP_EMPTY		0x4000	/* accept empty path [user_... only] */
  #define LOOKUP_DOWN		0x8000	/* follow mounts in the starting point */

  #define LOOKUP_MOUNTPOINT	0x0080	/* follow mounts in the end */

  
  #define LOOKUP_REVAL		0x0020	/* tell ->d_revalidate() to trust no cache */
  #define LOOKUP_RCU		0x0040	/* RCU pathwalk mode; semi-internal */
  
  /* These tell filesystem methods that we are dealing with the final component... */
  #define LOOKUP_OPEN		0x0100	/* ... in open */
  #define LOOKUP_CREATE		0x0200	/* ... in object creation */
  #define LOOKUP_EXCL		0x0400	/* ... in exclusive creation */
  #define LOOKUP_RENAME_TARGET	0x0800	/* ... in destination of rename() */
  
  /* internal use only */

  #define LOOKUP_PARENT		0x0010

  #define LOOKUP_JUMPED		0x1000

  #define LOOKUP_ROOT		0x2000

  #define LOOKUP_ROOT_GRABBED	0x0008

  /* Scoping flags for lookup. */
  #define LOOKUP_NO_SYMLINKS	0x010000 /* No symlink crossing. */

  #define LOOKUP_NO_MAGICLINKS	0x020000 /* No nd_jump_link() crossing. */

  #define LOOKUP_NO_XDEV		0x040000 /* No mountpoint crossing. */

  #define LOOKUP_BENEATH		0x080000 /* No escaping from starting point. */

  #define LOOKUP_IN_ROOT		0x100000 /* Treat dirfd as fs root. */

  /* LOOKUP_* flags which do scope-related checks based on the dirfd. */

  #define LOOKUP_IS_SCOPED (LOOKUP_BENEATH | LOOKUP_IN_ROOT)

  extern int path_pts(struct path *path);

  extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);

  static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
  		 struct path *path)
  {
  	return user_path_at_empty(dfd, name, flags, path, NULL);
  }

  extern int kern_path(const char *, unsigned, struct path *);

  extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
  extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);

  extern void done_path_create(struct path *, struct dentry *);

  extern struct dentry *kern_path_locked(const char *, struct path *);

  extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int);

  extern struct dentry *lookup_one_len(const char *, struct dentry *, int);

  extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);

  extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int);

  extern int follow_down_one(struct path *);

  extern int follow_down(struct path *);

  extern int follow_up(struct path *);

  
  extern struct dentry *lock_rename(struct dentry *, struct dentry *);
  extern void unlock_rename(struct dentry *, struct dentry *);

  extern int __must_check nd_jump_link(struct path *path);

  static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
  {
  	((char *) name)[min(len, maxlen)] = '\0';
  }

  /**
   * retry_estale - determine whether the caller should retry an operation
   * @error: the error that would currently be returned
   * @flags: flags being used for next lookup attempt
   *
   * Check to see if the error code was -ESTALE, and then determine whether
   * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
   *
   * Returns true if the caller should try the operation again.
   */
  static inline bool
  retry_estale(const long error, const unsigned int flags)
  {
  	return error == -ESTALE && !(flags & LOOKUP_REVAL);
  }

  #endif /* _LINUX_NAMEI_H */