1/*
2 * Inode based directory notification for Linux
3 *
4 * Copyright (C) 2005 John McCutchan
5 */
6
7#ifndef _LINUX_INOTIFY_H
8#define _LINUX_INOTIFY_H
9
10#include <linux/types.h>
11
12/*
13 * struct inotify_event - structure read from the inotify device for each event
14 *
15 * When you are watching a directory, you will receive the filename for events
16 * such as IN_CREATE, IN_DELETE, IN_OPEN, IN_CLOSE, ..., relative to the wd.
17 */
18struct inotify_event {
19	__s32		wd;		/* watch descriptor */
20	__u32		mask;		/* watch mask */
21	__u32		cookie;		/* cookie to synchronize two events */
22	__u32		len;		/* length (including nulls) of name */
23	char		name[0];	/* stub for possible name */
24};
25
26/* the following are legal, implemented events that user-space can watch for */
27#define IN_ACCESS		0x00000001	/* File was accessed */
28#define IN_MODIFY		0x00000002	/* File was modified */
29#define IN_ATTRIB		0x00000004	/* Metadata changed */
30#define IN_CLOSE_WRITE		0x00000008	/* Writtable file was closed */
31#define IN_CLOSE_NOWRITE	0x00000010	/* Unwrittable file closed */
32#define IN_OPEN			0x00000020	/* File was opened */
33#define IN_MOVED_FROM		0x00000040	/* File was moved from X */
34#define IN_MOVED_TO		0x00000080	/* File was moved to Y */
35#define IN_CREATE		0x00000100	/* Subfile was created */
36#define IN_DELETE		0x00000200	/* Subfile was deleted */
37#define IN_DELETE_SELF		0x00000400	/* Self was deleted */
38#define IN_MOVE_SELF		0x00000800	/* Self was moved */
39
40/* the following are legal events.  they are sent as needed to any watch */
41#define IN_UNMOUNT		0x00002000	/* Backing fs was unmounted */
42#define IN_Q_OVERFLOW		0x00004000	/* Event queued overflowed */
43#define IN_IGNORED		0x00008000	/* File was ignored */
44
45/* helper events */
46#define IN_CLOSE		(IN_CLOSE_WRITE | IN_CLOSE_NOWRITE) /* close */
47#define IN_MOVE			(IN_MOVED_FROM | IN_MOVED_TO) /* moves */
48
49/* special flags */
50#define IN_ONLYDIR		0x01000000	/* only watch the path if it is a directory */
51#define IN_DONT_FOLLOW		0x02000000	/* don't follow a sym link */
52#define IN_MASK_ADD		0x20000000	/* add to the mask of an already existing watch */
53#define IN_ISDIR		0x40000000	/* event occurred against dir */
54#define IN_ONESHOT		0x80000000	/* only send event once */
55
56/*
57 * All of the events - we build the list by hand so that we can add flags in
58 * the future and not break backward compatibility.  Apps will get only the
59 * events that they originally wanted.  Be sure to add new events here!
60 */
61#define IN_ALL_EVENTS	(IN_ACCESS | IN_MODIFY | IN_ATTRIB | IN_CLOSE_WRITE | \
62			 IN_CLOSE_NOWRITE | IN_OPEN | IN_MOVED_FROM | \
63			 IN_MOVED_TO | IN_DELETE | IN_CREATE | IN_DELETE_SELF | \
64			 IN_MOVE_SELF)
65
66#ifdef __KERNEL__
67
68#include <linux/dcache.h>
69#include <linux/fs.h>
70
71/*
72 * struct inotify_watch - represents a watch request on a specific inode
73 *
74 * h_list is protected by ih->mutex of the associated inotify_handle.
75 * i_list, mask are protected by inode->inotify_mutex of the associated inode.
76 * ih, inode, and wd are never written to once the watch is created.
77 *
78 * Callers must use the established inotify interfaces to access inotify_watch
79 * contents.  The content of this structure is private to the inotify
80 * implementation.
81 */
82struct inotify_watch {
83	struct list_head	h_list;	/* entry in inotify_handle's list */
84	struct list_head	i_list;	/* entry in inode's list */
85	atomic_t		count;	/* reference count */
86	struct inotify_handle	*ih;	/* associated inotify handle */
87	struct inode		*inode;	/* associated inode */
88	__s32			wd;	/* watch descriptor */
89	__u32			mask;	/* event mask for this watch */
90};
91
92struct inotify_operations {
93	void (*handle_event)(struct inotify_watch *, u32, u32, u32,
94			     const char *, struct inode *);
95	void (*destroy_watch)(struct inotify_watch *);
96};
97
98#ifdef CONFIG_INOTIFY
99
100/* Kernel API for producing events */
101
102extern void inotify_d_instantiate(struct dentry *, struct inode *);
103extern void inotify_d_move(struct dentry *);
104extern void inotify_inode_queue_event(struct inode *, __u32, __u32,
105				      const char *, struct inode *);
106extern void inotify_dentry_parent_queue_event(struct dentry *, __u32, __u32,
107					      const char *);
108extern void inotify_unmount_inodes(struct list_head *);
109extern void inotify_inode_is_dead(struct inode *);
110extern u32 inotify_get_cookie(void);
111
112/* Kernel Consumer API */
113
114extern struct inotify_handle *inotify_init(const struct inotify_operations *);
115extern void inotify_init_watch(struct inotify_watch *);
116extern void inotify_destroy(struct inotify_handle *);
117extern __s32 inotify_find_watch(struct inotify_handle *, struct inode *,
118				struct inotify_watch **);
119extern __s32 inotify_find_update_watch(struct inotify_handle *, struct inode *,
120				       u32);
121extern __s32 inotify_add_watch(struct inotify_handle *, struct inotify_watch *,
122			       struct inode *, __u32);
123extern int inotify_rm_watch(struct inotify_handle *, struct inotify_watch *);
124extern int inotify_rm_wd(struct inotify_handle *, __u32);
125extern void inotify_remove_watch_locked(struct inotify_handle *,
126					struct inotify_watch *);
127extern void get_inotify_watch(struct inotify_watch *);
128extern void put_inotify_watch(struct inotify_watch *);
129
130#else
131
132static inline void inotify_d_instantiate(struct dentry *dentry,
133					struct inode *inode)
134{
135}
136
137static inline void inotify_d_move(struct dentry *dentry)
138{
139}
140
141static inline void inotify_inode_queue_event(struct inode *inode,
142					     __u32 mask, __u32 cookie,
143					     const char *filename,
144					     struct inode *n_inode)
145{
146}
147
148static inline void inotify_dentry_parent_queue_event(struct dentry *dentry,
149						     __u32 mask, __u32 cookie,
150						     const char *filename)
151{
152}
153
154static inline void inotify_unmount_inodes(struct list_head *list)
155{
156}
157
158static inline void inotify_inode_is_dead(struct inode *inode)
159{
160}
161
162static inline u32 inotify_get_cookie(void)
163{
164	return 0;
165}
166
167static inline struct inotify_handle *inotify_init(const struct inotify_operations *ops)
168{
169	return ERR_PTR(-EOPNOTSUPP);
170}
171
172static inline void inotify_init_watch(struct inotify_watch *watch)
173{
174}
175
176static inline void inotify_destroy(struct inotify_handle *ih)
177{
178}
179
180static inline __s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode,
181				       struct inotify_watch **watchp)
182{
183	return -EOPNOTSUPP;
184}
185
186static inline __s32 inotify_find_update_watch(struct inotify_handle *ih,
187					      struct inode *inode, u32 mask)
188{
189	return -EOPNOTSUPP;
190}
191
192static inline __s32 inotify_add_watch(struct inotify_handle *ih,
193				      struct inotify_watch *watch,
194				      struct inode *inode, __u32 mask)
195{
196	return -EOPNOTSUPP;
197}
198
199static inline int inotify_rm_watch(struct inotify_handle *ih,
200				   struct inotify_watch *watch)
201{
202	return -EOPNOTSUPP;
203}
204
205static inline int inotify_rm_wd(struct inotify_handle *ih, __u32 wd)
206{
207	return -EOPNOTSUPP;
208}
209
210static inline void inotify_remove_watch_locked(struct inotify_handle *ih,
211					       struct inotify_watch *watch)
212{
213}
214
215static inline void get_inotify_watch(struct inotify_watch *watch)
216{
217}
218
219static inline void put_inotify_watch(struct inotify_watch *watch)
220{
221}
222
223#endif	/* CONFIG_INOTIFY */
224
225#endif	/* __KERNEL __ */
226
227#endif	/* _LINUX_INOTIFY_H */
228