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 /* For O_CLOEXEC and O_NONBLOCK */
  11 #include <linux/fcntl.h>
  12 #include <linux/types.h>
  13
  14 /*
  15  * struct inotify_event - structure read from the inotify device for each event
  16  *
  17  * When you are watching a directory, you will receive the filename for events
  18  * such as IN_CREATE, IN_DELETE, IN_OPEN, IN_CLOSE, ..., relative to the wd.
  19  */
  20 struct inotify_event {
  21         __s32           wd;             /* watch descriptor */
  22         __u32           mask;           /* watch mask */
  23         __u32           cookie;         /* cookie to synchronize two events */
  24         __u32           len;            /* length (including nulls) of name */
  25         char            name[0];        /* stub for possible name */
  26 };
  27
  28 /* the following are legal, implemented events that user-space can watch for */
  29 #define IN_ACCESS               0x00000001      /* File was accessed */
  30 #define IN_MODIFY               0x00000002      /* File was modified */
  31 #define IN_ATTRIB               0x00000004      /* Metadata changed */
  32 #define IN_CLOSE_WRITE          0x00000008      /* Writtable file was closed */
  33 #define IN_CLOSE_NOWRITE        0x00000010      /* Unwrittable file closed */
  34 #define IN_OPEN                 0x00000020      /* File was opened */
  35 #define IN_MOVED_FROM           0x00000040      /* File was moved from X */
  36 #define IN_MOVED_TO             0x00000080      /* File was moved to Y */
  37 #define IN_CREATE               0x00000100      /* Subfile was created */
  38 #define IN_DELETE               0x00000200      /* Subfile was deleted */
  39 #define IN_DELETE_SELF          0x00000400      /* Self was deleted */
  40 #define IN_MOVE_SELF            0x00000800      /* Self was moved */
  41
  42 /* the following are legal events.  they are sent as needed to any watch */
  43 #define IN_UNMOUNT              0x00002000      /* Backing fs was unmounted */
  44 #define IN_Q_OVERFLOW           0x00004000      /* Event queued overflowed */
  45 #define IN_IGNORED              0x00008000      /* File was ignored */
  46
  47 /* helper events */
  48 #define IN_CLOSE                (IN_CLOSE_WRITE | IN_CLOSE_NOWRITE) /* close */
  49 #define IN_MOVE                 (IN_MOVED_FROM | IN_MOVED_TO) /* moves */
  50
  51 /* special flags */
  52 #define IN_ONLYDIR              0x01000000      /* only watch the path if it is a directory */
  53 #define IN_DONT_FOLLOW          0x02000000      /* don't follow a sym link */
  54 #define IN_MASK_ADD             0x20000000      /* add to the mask of an already existing watch */
  55 #define IN_ISDIR                0x40000000      /* event occurred against dir */
  56 #define IN_ONESHOT              0x80000000      /* only send event once */
  57
  58 /*
  59  * All of the events - we build the list by hand so that we can add flags in
  60  * the future and not break backward compatibility.  Apps will get only the
  61  * events that they originally wanted.  Be sure to add new events here!
  62  */
  63 #define IN_ALL_EVENTS   (IN_ACCESS | IN_MODIFY | IN_ATTRIB | IN_CLOSE_WRITE | \
  64                          IN_CLOSE_NOWRITE | IN_OPEN | IN_MOVED_FROM | \
  65                          IN_MOVED_TO | IN_DELETE | IN_CREATE | IN_DELETE_SELF | \
  66                          IN_MOVE_SELF)
  67
  68 /* Flags for sys_inotify_init1.  */
  69 #define IN_CLOEXEC O_CLOEXEC
  70 #define IN_NONBLOCK O_NONBLOCK
  71
  72 #ifdef __KERNEL__
  73
  74 #include <linux/dcache.h>
  75 #include <linux/fs.h>
  76
  77 /*
  78  * struct inotify_watch - represents a watch request on a specific inode
  79  *
  80  * h_list is protected by ih->mutex of the associated inotify_handle.
  81  * i_list, mask are protected by inode->inotify_mutex of the associated inode.
  82  * ih, inode, and wd are never written to once the watch is created.
  83  *
  84  * Callers must use the established inotify interfaces to access inotify_watch
  85  * contents.  The content of this structure is private to the inotify
  86  * implementation.
  87  */
  88 struct inotify_watch {
  89         struct list_head        h_list; /* entry in inotify_handle's list */
  90         struct list_head        i_list; /* entry in inode's list */
  91         atomic_t                count;  /* reference count */
  92         struct inotify_handle   *ih;    /* associated inotify handle */
  93         struct inode            *inode; /* associated inode */
  94         __s32                   wd;     /* watch descriptor */
  95         __u32                   mask;   /* event mask for this watch */
  96 };
  97
  98 struct inotify_operations {
  99         void (*handle_event)(struct inotify_watch *, u32, u32, u32,
 100                              const char *, struct inode *);
 101         void (*destroy_watch)(struct inotify_watch *);
 102 };
 103
 104 #ifdef CONFIG_INOTIFY
 105
 106 /* Kernel API for producing events */
 107
 108 extern void inotify_d_instantiate(struct dentry *, struct inode *);
 109 extern void inotify_d_move(struct dentry *);
 110 extern void inotify_inode_queue_event(struct inode *, __u32, __u32,
 111                                       const char *, struct inode *);
 112 extern void inotify_dentry_parent_queue_event(struct dentry *, __u32, __u32,
 113                                               const char *);
 114 extern void inotify_unmount_inodes(struct list_head *);
 115 extern void inotify_inode_is_dead(struct inode *);
 116 extern u32 inotify_get_cookie(void);
 117
 118 /* Kernel Consumer API */
 119
 120 extern struct inotify_handle *inotify_init(const struct inotify_operations *);
 121 extern void inotify_init_watch(struct inotify_watch *);
 122 extern void inotify_destroy(struct inotify_handle *);
 123 extern __s32 inotify_find_watch(struct inotify_handle *, struct inode *,
 124                                 struct inotify_watch **);
 125 extern __s32 inotify_find_update_watch(struct inotify_handle *, struct inode *,
 126                                        u32);
 127 extern __s32 inotify_add_watch(struct inotify_handle *, struct inotify_watch *,
 128                                struct inode *, __u32);
 129 extern __s32 inotify_clone_watch(struct inotify_watch *, struct inotify_watch *);
 130 extern void inotify_evict_watch(struct inotify_watch *);
 131 extern int inotify_rm_watch(struct inotify_handle *, struct inotify_watch *);
 132 extern int inotify_rm_wd(struct inotify_handle *, __u32);
 133 extern void inotify_remove_watch_locked(struct inotify_handle *,
 134                                         struct inotify_watch *);
 135 extern void get_inotify_watch(struct inotify_watch *);
 136 extern void put_inotify_watch(struct inotify_watch *);
 137
 138 #else
 139
 140 static inline void inotify_d_instantiate(struct dentry *dentry,
 141                                         struct inode *inode)
 142 {
 143 }
 144
 145 static inline void inotify_d_move(struct dentry *dentry)
 146 {
 147 }
 148
 149 static inline void inotify_inode_queue_event(struct inode *inode,
 150                                              __u32 mask, __u32 cookie,
 151                                              const char *filename,
 152                                              struct inode *n_inode)
 153 {
 154 }
 155
 156 static inline void inotify_dentry_parent_queue_event(struct dentry *dentry,
 157                                                      __u32 mask, __u32 cookie,
 158                                                      const char *filename)
 159 {
 160 }
 161
 162 static inline void inotify_unmount_inodes(struct list_head *list)
 163 {
 164 }
 165
 166 static inline void inotify_inode_is_dead(struct inode *inode)
 167 {
 168 }
 169
 170 static inline u32 inotify_get_cookie(void)
 171 {
 172         return 0;
 173 }
 174
 175 static inline struct inotify_handle *inotify_init(const struct inotify_operations *ops)
 176 {
 177         return ERR_PTR(-EOPNOTSUPP);
 178 }
 179
 180 static inline void inotify_init_watch(struct inotify_watch *watch)
 181 {
 182 }
 183
 184 static inline void inotify_destroy(struct inotify_handle *ih)
 185 {
 186 }
 187
 188 static inline __s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode,
 189                                        struct inotify_watch **watchp)
 190 {
 191         return -EOPNOTSUPP;
 192 }
 193
 194 static inline __s32 inotify_find_update_watch(struct inotify_handle *ih,
 195                                               struct inode *inode, u32 mask)
 196 {
 197         return -EOPNOTSUPP;
 198 }
 199
 200 static inline __s32 inotify_add_watch(struct inotify_handle *ih,
 201                                       struct inotify_watch *watch,
 202                                       struct inode *inode, __u32 mask)
 203 {
 204         return -EOPNOTSUPP;
 205 }
 206
 207 static inline int inotify_rm_watch(struct inotify_handle *ih,
 208                                    struct inotify_watch *watch)
 209 {
 210         return -EOPNOTSUPP;
 211 }
 212
 213 static inline int inotify_rm_wd(struct inotify_handle *ih, __u32 wd)
 214 {
 215         return -EOPNOTSUPP;
 216 }
 217
 218 static inline void inotify_remove_watch_locked(struct inotify_handle *ih,
 219                                                struct inotify_watch *watch)
 220 {
 221 }
 222
 223 static inline void get_inotify_watch(struct inotify_watch *watch)
 224 {
 225 }
 226
 227 static inline void put_inotify_watch(struct inotify_watch *watch)
 228 {
 229 }
 230
 231 #endif  /* CONFIG_INOTIFY */
 232
 233 #endif  /* __KERNEL __ */
 234
 235 #endif  /* _LINUX_INOTIFY_H */