/*
   * Inode based directory notification for Linux
   *
   * Copyright (C) 2005 John McCutchan
   */
  
  #ifndef _LINUX_INOTIFY_H
  #define _LINUX_INOTIFY_H

  /* For O_CLOEXEC and O_NONBLOCK */

  #include <linux/fcntl.h>

  #include <linux/types.h>
  
  /*
   * struct inotify_event - structure read from the inotify device for each event
   *
   * When you are watching a directory, you will receive the filename for events
   * such as IN_CREATE, IN_DELETE, IN_OPEN, IN_CLOSE, ..., relative to the wd.
   */
  struct inotify_event {
  	__s32		wd;		/* watch descriptor */
  	__u32		mask;		/* watch mask */
  	__u32		cookie;		/* cookie to synchronize two events */
  	__u32		len;		/* length (including nulls) of name */
  	char		name[0];	/* stub for possible name */
  };
  
  /* the following are legal, implemented events that user-space can watch for */
  #define IN_ACCESS		0x00000001	/* File was accessed */
  #define IN_MODIFY		0x00000002	/* File was modified */
  #define IN_ATTRIB		0x00000004	/* Metadata changed */
  #define IN_CLOSE_WRITE		0x00000008	/* Writtable file was closed */
  #define IN_CLOSE_NOWRITE	0x00000010	/* Unwrittable file closed */
  #define IN_OPEN			0x00000020	/* File was opened */
  #define IN_MOVED_FROM		0x00000040	/* File was moved from X */
  #define IN_MOVED_TO		0x00000080	/* File was moved to Y */
  #define IN_CREATE		0x00000100	/* Subfile was created */
  #define IN_DELETE		0x00000200	/* Subfile was deleted */
  #define IN_DELETE_SELF		0x00000400	/* Self was deleted */

  #define IN_MOVE_SELF		0x00000800	/* Self was moved */

  
  /* the following are legal events.  they are sent as needed to any watch */
  #define IN_UNMOUNT		0x00002000	/* Backing fs was unmounted */
  #define IN_Q_OVERFLOW		0x00004000	/* Event queued overflowed */
  #define IN_IGNORED		0x00008000	/* File was ignored */
  
  /* helper events */
  #define IN_CLOSE		(IN_CLOSE_WRITE | IN_CLOSE_NOWRITE) /* close */
  #define IN_MOVE			(IN_MOVED_FROM | IN_MOVED_TO) /* moves */
  
  /* special flags */

  #define IN_ONLYDIR		0x01000000	/* only watch the path if it is a directory */
  #define IN_DONT_FOLLOW		0x02000000	/* don't follow a sym link */

  #define IN_MASK_ADD		0x20000000	/* add to the mask of an already existing watch */

  #define IN_ISDIR		0x40000000	/* event occurred against dir */
  #define IN_ONESHOT		0x80000000	/* only send event once */
  
  /*
   * All of the events - we build the list by hand so that we can add flags in
   * the future and not break backward compatibility.  Apps will get only the
   * events that they originally wanted.  Be sure to add new events here!
   */
  #define IN_ALL_EVENTS	(IN_ACCESS | IN_MODIFY | IN_ATTRIB | IN_CLOSE_WRITE | \
  			 IN_CLOSE_NOWRITE | IN_OPEN | IN_MOVED_FROM | \

  			 IN_MOVED_TO | IN_DELETE | IN_CREATE | IN_DELETE_SELF | \
  			 IN_MOVE_SELF)

  /* Flags for sys_inotify_init1.  */
  #define IN_CLOEXEC O_CLOEXEC

  #define IN_NONBLOCK O_NONBLOCK

  #ifdef __KERNEL__
  
  #include <linux/dcache.h>
  #include <linux/fs.h>

  /*
   * struct inotify_watch - represents a watch request on a specific inode
   *
   * h_list is protected by ih->mutex of the associated inotify_handle.
   * i_list, mask are protected by inode->inotify_mutex of the associated inode.
   * ih, inode, and wd are never written to once the watch is created.
   *
   * Callers must use the established inotify interfaces to access inotify_watch
   * contents.  The content of this structure is private to the inotify
   * implementation.
   */
  struct inotify_watch {
  	struct list_head	h_list;	/* entry in inotify_handle's list */
  	struct list_head	i_list;	/* entry in inode's list */
  	atomic_t		count;	/* reference count */
  	struct inotify_handle	*ih;	/* associated inotify handle */
  	struct inode		*inode;	/* associated inode */
  	__s32			wd;	/* watch descriptor */
  	__u32			mask;	/* event mask for this watch */
  };
  
  struct inotify_operations {
  	void (*handle_event)(struct inotify_watch *, u32, u32, u32,

  			     const char *, struct inode *);

  	void (*destroy_watch)(struct inotify_watch *);
  };

  #ifdef CONFIG_INOTIFY

  /* Kernel API for producing events */

  extern void inotify_d_instantiate(struct dentry *, struct inode *);
  extern void inotify_d_move(struct dentry *);

  extern void inotify_inode_queue_event(struct inode *, __u32, __u32,

  				      const char *, struct inode *);

  extern void inotify_dentry_parent_queue_event(struct dentry *, __u32, __u32,
  					      const char *);
  extern void inotify_unmount_inodes(struct list_head *);
  extern void inotify_inode_is_dead(struct inode *);
  extern u32 inotify_get_cookie(void);

  /* Kernel Consumer API */
  
  extern struct inotify_handle *inotify_init(const struct inotify_operations *);

  extern void inotify_init_watch(struct inotify_watch *);

  extern void inotify_destroy(struct inotify_handle *);

  extern __s32 inotify_find_watch(struct inotify_handle *, struct inode *,
  				struct inotify_watch **);

  extern __s32 inotify_find_update_watch(struct inotify_handle *, struct inode *,
  				       u32);
  extern __s32 inotify_add_watch(struct inotify_handle *, struct inotify_watch *,
  			       struct inode *, __u32);

  extern __s32 inotify_clone_watch(struct inotify_watch *, struct inotify_watch *);

  extern void inotify_evict_watch(struct inotify_watch *);

  extern int inotify_rm_watch(struct inotify_handle *, struct inotify_watch *);

  extern int inotify_rm_wd(struct inotify_handle *, __u32);

  extern void inotify_remove_watch_locked(struct inotify_handle *,
  					struct inotify_watch *);

  extern void get_inotify_watch(struct inotify_watch *);
  extern void put_inotify_watch(struct inotify_watch *);

  #else

  static inline void inotify_d_instantiate(struct dentry *dentry,
  					struct inode *inode)
  {
  }
  
  static inline void inotify_d_move(struct dentry *dentry)
  {
  }

  static inline void inotify_inode_queue_event(struct inode *inode,
  					     __u32 mask, __u32 cookie,

  					     const char *filename,
  					     struct inode *n_inode)

  {
  }
  
  static inline void inotify_dentry_parent_queue_event(struct dentry *dentry,
  						     __u32 mask, __u32 cookie,
  						     const char *filename)
  {
  }
  
  static inline void inotify_unmount_inodes(struct list_head *list)
  {
  }
  
  static inline void inotify_inode_is_dead(struct inode *inode)
  {
  }
  
  static inline u32 inotify_get_cookie(void)
  {
  	return 0;
  }

  static inline struct inotify_handle *inotify_init(const struct inotify_operations *ops)
  {
  	return ERR_PTR(-EOPNOTSUPP);
  }

  static inline void inotify_init_watch(struct inotify_watch *watch)
  {
  }

  static inline void inotify_destroy(struct inotify_handle *ih)
  {
  }

  static inline __s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode,
  				       struct inotify_watch **watchp)
  {
  	return -EOPNOTSUPP;
  }

  static inline __s32 inotify_find_update_watch(struct inotify_handle *ih,
  					      struct inode *inode, u32 mask)
  {
  	return -EOPNOTSUPP;
  }
  
  static inline __s32 inotify_add_watch(struct inotify_handle *ih,
  				      struct inotify_watch *watch,
  				      struct inode *inode, __u32 mask)
  {
  	return -EOPNOTSUPP;
  }

  static inline int inotify_rm_watch(struct inotify_handle *ih,
  				   struct inotify_watch *watch)
  {
  	return -EOPNOTSUPP;
  }

  static inline int inotify_rm_wd(struct inotify_handle *ih, __u32 wd)
  {
  	return -EOPNOTSUPP;
  }

  static inline void inotify_remove_watch_locked(struct inotify_handle *ih,
  					       struct inotify_watch *watch)
  {
  }

  static inline void get_inotify_watch(struct inotify_watch *watch)
  {
  }
  
  static inline void put_inotify_watch(struct inotify_watch *watch)
  {
  }

  #endif	/* CONFIG_INOTIFY */
  
  #endif	/* __KERNEL __ */
  
  #endif	/* _LINUX_INOTIFY_H */