Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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  */
 18 struct 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  */
 82 struct 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 
 92 struct 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 
102 extern void inotify_d_instantiate(struct dentry *, struct inode *);
103 extern void inotify_d_move(struct dentry *);
104 extern void inotify_inode_queue_event(struct inode *, __u32, __u32,
105                                       const char *, struct inode *);
106 extern void inotify_dentry_parent_queue_event(struct dentry *, __u32, __u32,
107                                               const char *);
108 extern void inotify_unmount_inodes(struct list_head *);
109 extern void inotify_inode_is_dead(struct inode *);
110 extern u32 inotify_get_cookie(void);
111 
112 /* Kernel Consumer API */
113 
114 extern struct inotify_handle *inotify_init(const struct inotify_operations *);
115 extern void inotify_init_watch(struct inotify_watch *);
116 extern void inotify_destroy(struct inotify_handle *);
117 extern __s32 inotify_find_watch(struct inotify_handle *, struct inode *,
118                                 struct inotify_watch **);
119 extern __s32 inotify_find_update_watch(struct inotify_handle *, struct inode *,
120                                        u32);
121 extern __s32 inotify_add_watch(struct inotify_handle *, struct inotify_watch *,
122                                struct inode *, __u32);
123 extern __s32 inotify_clone_watch(struct inotify_watch *, struct inotify_watch *);
124 extern void inotify_evict_watch(struct inotify_watch *);
125 extern int inotify_rm_watch(struct inotify_handle *, struct inotify_watch *);
126 extern int inotify_rm_wd(struct inotify_handle *, __u32);
127 extern void inotify_remove_watch_locked(struct inotify_handle *,
128                                         struct inotify_watch *);
129 extern void get_inotify_watch(struct inotify_watch *);
130 extern void put_inotify_watch(struct inotify_watch *);
131 
132 #else
133 
134 static inline void inotify_d_instantiate(struct dentry *dentry,
135                                         struct inode *inode)
136 {
137 }
138 
139 static inline void inotify_d_move(struct dentry *dentry)
140 {
141 }
142 
143 static 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 
150 static inline void inotify_dentry_parent_queue_event(struct dentry *dentry,
151                                                      __u32 mask, __u32 cookie,
152                                                      const char *filename)
153 {
154 }
155 
156 static inline void inotify_unmount_inodes(struct list_head *list)
157 {
158 }
159 
160 static inline void inotify_inode_is_dead(struct inode *inode)
161 {
162 }
163 
164 static inline u32 inotify_get_cookie(void)
165 {
166         return 0;
167 }
168 
169 static inline struct inotify_handle *inotify_init(const struct inotify_operations *ops)
170 {
171         return ERR_PTR(-EOPNOTSUPP);
172 }
173 
174 static inline void inotify_init_watch(struct inotify_watch *watch)
175 {
176 }
177 
178 static inline void inotify_destroy(struct inotify_handle *ih)
179 {
180 }
181 
182 static inline __s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode,
183                                        struct inotify_watch **watchp)
184 {
185         return -EOPNOTSUPP;
186 }
187 
188 static inline __s32 inotify_find_update_watch(struct inotify_handle *ih,
189                                               struct inode *inode, u32 mask)
190 {
191         return -EOPNOTSUPP;
192 }
193 
194 static 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 
201 static inline int inotify_rm_watch(struct inotify_handle *ih,
202                                    struct inotify_watch *watch)
203 {
204         return -EOPNOTSUPP;
205 }
206 
207 static inline int inotify_rm_wd(struct inotify_handle *ih, __u32 wd)
208 {
209         return -EOPNOTSUPP;
210 }
211 
212 static inline void inotify_remove_watch_locked(struct inotify_handle *ih,
213                                                struct inotify_watch *watch)
214 {
215 }
216 
217 static inline void get_inotify_watch(struct inotify_watch *watch)
218 {
219 }
220 
221 static 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 */
230 
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