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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 __s32 inotify_clone_watch(struct inotify_watch *, struct inotify_watch *);
124extern void inotify_evict_watch(struct inotify_watch *);
125extern int inotify_rm_watch(struct inotify_handle *, struct inotify_watch *);
126extern int inotify_rm_wd(struct inotify_handle *, __u32);
127extern void inotify_remove_watch_locked(struct inotify_handle *,
128 struct inotify_watch *);
129extern void get_inotify_watch(struct inotify_watch *);
130extern void put_inotify_watch(struct inotify_watch *);
131
132#else
133
134static inline void inotify_d_instantiate(struct dentry *dentry,
135 struct inode *inode)
136{
137}
138
139static inline void inotify_d_move(struct dentry *dentry)
140{
141}
142
143static inline void inotify_inode_queue_event(struct inode *inode,
144 __u32 mask, __u32 cookie,
145 const char *filename,
146 struct inode *n_inode)
147{
148}
149
150static inline void inotify_dentry_parent_queue_event(struct dentry *dentry,
151 __u32 mask, __u32 cookie,
152 const char *filename)
153{
154}
155
156static inline void inotify_unmount_inodes(struct list_head *list)
157{
158}
159
160static inline void inotify_inode_is_dead(struct inode *inode)
161{
162}
163
164static inline u32 inotify_get_cookie(void)
165{
166 return 0;
167}
168
169static inline struct inotify_handle *inotify_init(const struct inotify_operations *ops)
170{
171 return ERR_PTR(-EOPNOTSUPP);
172}
173
174static inline void inotify_init_watch(struct inotify_watch *watch)
175{
176}
177
178static inline void inotify_destroy(struct inotify_handle *ih)
179{
180}
181
182static inline __s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode,
183 struct inotify_watch **watchp)
184{
185 return -EOPNOTSUPP;
186}
187
188static inline __s32 inotify_find_update_watch(struct inotify_handle *ih,
189 struct inode *inode, u32 mask)
190{
191 return -EOPNOTSUPP;
192}
193
194static inline __s32 inotify_add_watch(struct inotify_handle *ih,
195 struct inotify_watch *watch,
196 struct inode *inode, __u32 mask)
197{
198 return -EOPNOTSUPP;
199}
200
201static inline int inotify_rm_watch(struct inotify_handle *ih,
202 struct inotify_watch *watch)
203{
204 return -EOPNOTSUPP;
205}
206
207static inline int inotify_rm_wd(struct inotify_handle *ih, __u32 wd)
208{
209 return -EOPNOTSUPP;
210}
211
212static inline void inotify_remove_watch_locked(struct inotify_handle *ih,
213 struct inotify_watch *watch)
214{
215}
216
217static inline void get_inotify_watch(struct inotify_watch *watch)
218{
219}
220
221static inline void put_inotify_watch(struct inotify_watch *watch)
222{
223}
224
225#endif /* CONFIG_INOTIFY */
226
227#endif /* __KERNEL __ */
228
229#endif /* _LINUX_INOTIFY_H */