include/linux/inotify.h

   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 *);
  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 *);
 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_destroy(struct inotify_handle *);
 116 extern __s32 inotify_find_update_watch(struct inotify_handle *, struct inode *,
 117                                        u32);
 118 extern __s32 inotify_add_watch(struct inotify_handle *, struct inotify_watch *,
 119                                struct inode *, __u32);
 120 extern int inotify_rm_wd(struct inotify_handle *, __u32);
 121 extern void get_inotify_watch(struct inotify_watch *);
 122 extern void put_inotify_watch(struct inotify_watch *);
 123
 124 #else
 125
 126 static inline void inotify_d_instantiate(struct dentry *dentry,
 127                                         struct inode *inode)
 128 {
 129 }
 130
 131 static inline void inotify_d_move(struct dentry *dentry)
 132 {
 133 }
 134
 135 static inline void inotify_inode_queue_event(struct inode *inode,
 136                                              __u32 mask, __u32 cookie,
 137                                              const char *filename)
 138 {
 139 }
 140
 141 static inline void inotify_dentry_parent_queue_event(struct dentry *dentry,
 142                                                      __u32 mask, __u32 cookie,
 143                                                      const char *filename)
 144 {
 145 }
 146
 147 static inline void inotify_unmount_inodes(struct list_head *list)
 148 {
 149 }
 150
 151 static inline void inotify_inode_is_dead(struct inode *inode)
 152 {
 153 }
 154
 155 static inline u32 inotify_get_cookie(void)
 156 {
 157         return 0;
 158 }
 159
 160 static inline struct inotify_handle *inotify_init(const struct inotify_operations *ops)
 161 {
 162         return ERR_PTR(-EOPNOTSUPP);
 163 }
 164
 165 static inline void inotify_destroy(struct inotify_handle *ih)
 166 {
 167 }
 168
 169 static inline __s32 inotify_find_update_watch(struct inotify_handle *ih,
 170                                               struct inode *inode, u32 mask)
 171 {
 172         return -EOPNOTSUPP;
 173 }
 174
 175 static inline __s32 inotify_add_watch(struct inotify_handle *ih,
 176                                       struct inotify_watch *watch,
 177                                       struct inode *inode, __u32 mask)
 178 {
 179         return -EOPNOTSUPP;
 180 }
 181
 182 static inline int inotify_rm_wd(struct inotify_handle *ih, __u32 wd)
 183 {
 184         return -EOPNOTSUPP;
 185 }
 186
 187 static inline void get_inotify_watch(struct inotify_watch *watch)
 188 {
 189 }
 190
 191 static inline void put_inotify_watch(struct inotify_watch *watch)
 192 {
 193 }
 194
 195 #endif  /* CONFIG_INOTIFY */
 196
 197 #endif  /* __KERNEL __ */
 198
 199 #endif  /* _LINUX_INOTIFY_H */