/*
 * 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 *);
extern int pin_inotify_watch(struct inotify_watch *);
extern void unpin_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)
{
}

extern inline int pin_inotify_watch(struct inotify_watch *watch)
{
        return 0;
}

extern inline void unpin_inotify_watch(struct inotify_watch *watch)
{
}

#endif  /* CONFIG_INOTIFY */

#endif  /* __KERNEL __ */

#endif  /* _LINUX_INOTIFY_H */