include/linux/fsnotify.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_FS_NOTIFY_H
   3 #define _LINUX_FS_NOTIFY_H
   4
   5 /*
   6  * include/linux/fsnotify.h - generic hooks for filesystem notification, to
   7  * reduce in-source duplication from both dnotify and inotify.
   8  *
   9  * We don't compile any of this away in some complicated menagerie of ifdefs.
  10  * Instead, we rely on the code inside to optimize away as needed.
  11  *
  12  * (C) Copyright 2005 Robert Love
  13  */
  14
  15 #include <linux/fsnotify_backend.h>
  16 #include <linux/audit.h>
  17 #include <linux/slab.h>
  18 #include <linux/bug.h>
  19
  20 /* Notify this dentry's parent about a child's events. */
  21 static inline int fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask)
  22 {
  23         if (!dentry)
  24                 dentry = path->dentry;
  25
  26         return __fsnotify_parent(path, dentry, mask);
  27 }
  28
  29 /* simple call site for access decisions */
  30 static inline int fsnotify_perm(struct file *file, int mask)
  31 {
  32         const struct path *path = &file->f_path;
  33         struct inode *inode = file_inode(file);
  34         __u32 fsnotify_mask = 0;
  35         int ret;
  36
  37         if (file->f_mode & FMODE_NONOTIFY)
  38                 return 0;
  39         if (!(mask & (MAY_READ | MAY_OPEN)))
  40                 return 0;
  41         if (mask & MAY_OPEN)
  42                 fsnotify_mask = FS_OPEN_PERM;
  43         else if (mask & MAY_READ)
  44                 fsnotify_mask = FS_ACCESS_PERM;
  45         else
  46                 BUG();
  47
  48         ret = fsnotify_parent(path, NULL, fsnotify_mask);
  49         if (ret)
  50                 return ret;
  51
  52         return fsnotify(inode, fsnotify_mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
  53 }
  54
  55 /*
  56  * fsnotify_link_count - inode's link count changed
  57  */
  58 static inline void fsnotify_link_count(struct inode *inode)
  59 {
  60         fsnotify(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
  61 }
  62
  63 /*
  64  * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
  65  */
  66 static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
  67                                  const unsigned char *old_name,
  68                                  int isdir, struct inode *target, struct dentry *moved)
  69 {
  70         struct inode *source = moved->d_inode;
  71         u32 fs_cookie = fsnotify_get_cookie();
  72         __u32 old_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_FROM);
  73         __u32 new_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_TO);
  74         const unsigned char *new_name = moved->d_name.name;
  75
  76         if (old_dir == new_dir)
  77                 old_dir_mask |= FS_DN_RENAME;
  78
  79         if (isdir) {
  80                 old_dir_mask |= FS_ISDIR;
  81                 new_dir_mask |= FS_ISDIR;
  82         }
  83
  84         fsnotify(old_dir, old_dir_mask, source, FSNOTIFY_EVENT_INODE, old_name,
  85                  fs_cookie);
  86         fsnotify(new_dir, new_dir_mask, source, FSNOTIFY_EVENT_INODE, new_name,
  87                  fs_cookie);
  88
  89         if (target)
  90                 fsnotify_link_count(target);
  91
  92         if (source)
  93                 fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE, NULL, 0);
  94         audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
  95 }
  96
  97 /*
  98  * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
  99  */
 100 static inline void fsnotify_inode_delete(struct inode *inode)
 101 {
 102         __fsnotify_inode_delete(inode);
 103 }
 104
 105 /*
 106  * fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
 107  */
 108 static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
 109 {
 110         __fsnotify_vfsmount_delete(mnt);
 111 }
 112
 113 /*
 114  * fsnotify_nameremove - a filename was removed from a directory
 115  */
 116 static inline void fsnotify_nameremove(struct dentry *dentry, int isdir)
 117 {
 118         __u32 mask = FS_DELETE;
 119
 120         if (isdir)
 121                 mask |= FS_ISDIR;
 122
 123         fsnotify_parent(NULL, dentry, mask);
 124 }
 125
 126 /*
 127  * fsnotify_inoderemove - an inode is going away
 128  */
 129 static inline void fsnotify_inoderemove(struct inode *inode)
 130 {
 131         fsnotify(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
 132         __fsnotify_inode_delete(inode);
 133 }
 134
 135 /*
 136  * fsnotify_create - 'name' was linked in
 137  */
 138 static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
 139 {
 140         audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
 141
 142         fsnotify(inode, FS_CREATE, dentry->d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
 143 }
 144
 145 /*
 146  * fsnotify_link - new hardlink in 'inode' directory
 147  * Note: We have to pass also the linked inode ptr as some filesystems leave
 148  *   new_dentry->d_inode NULL and instantiate inode pointer later
 149  */
 150 static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct dentry *new_dentry)
 151 {
 152         fsnotify_link_count(inode);
 153         audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
 154
 155         fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, new_dentry->d_name.name, 0);
 156 }
 157
 158 /*
 159  * fsnotify_mkdir - directory 'name' was created
 160  */
 161 static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 162 {
 163         __u32 mask = (FS_CREATE | FS_ISDIR);
 164         struct inode *d_inode = dentry->d_inode;
 165
 166         audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
 167
 168         fsnotify(inode, mask, d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
 169 }
 170
 171 /*
 172  * fsnotify_access - file was read
 173  */
 174 static inline void fsnotify_access(struct file *file)
 175 {
 176         const struct path *path = &file->f_path;
 177         struct inode *inode = file_inode(file);
 178         __u32 mask = FS_ACCESS;
 179
 180         if (S_ISDIR(inode->i_mode))
 181                 mask |= FS_ISDIR;
 182
 183         if (!(file->f_mode & FMODE_NONOTIFY)) {
 184                 fsnotify_parent(path, NULL, mask);
 185                 fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
 186         }
 187 }
 188
 189 /*
 190  * fsnotify_modify - file was modified
 191  */
 192 static inline void fsnotify_modify(struct file *file)
 193 {
 194         const struct path *path = &file->f_path;
 195         struct inode *inode = file_inode(file);
 196         __u32 mask = FS_MODIFY;
 197
 198         if (S_ISDIR(inode->i_mode))
 199                 mask |= FS_ISDIR;
 200
 201         if (!(file->f_mode & FMODE_NONOTIFY)) {
 202                 fsnotify_parent(path, NULL, mask);
 203                 fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
 204         }
 205 }
 206
 207 /*
 208  * fsnotify_open - file was opened
 209  */
 210 static inline void fsnotify_open(struct file *file)
 211 {
 212         const struct path *path = &file->f_path;
 213         struct inode *inode = file_inode(file);
 214         __u32 mask = FS_OPEN;
 215
 216         if (S_ISDIR(inode->i_mode))
 217                 mask |= FS_ISDIR;
 218
 219         fsnotify_parent(path, NULL, mask);
 220         fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
 221 }
 222
 223 /*
 224  * fsnotify_close - file was closed
 225  */
 226 static inline void fsnotify_close(struct file *file)
 227 {
 228         const struct path *path = &file->f_path;
 229         struct inode *inode = file_inode(file);
 230         fmode_t mode = file->f_mode;
 231         __u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
 232
 233         if (S_ISDIR(inode->i_mode))
 234                 mask |= FS_ISDIR;
 235
 236         if (!(file->f_mode & FMODE_NONOTIFY)) {
 237                 fsnotify_parent(path, NULL, mask);
 238                 fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
 239         }
 240 }
 241
 242 /*
 243  * fsnotify_xattr - extended attributes were changed
 244  */
 245 static inline void fsnotify_xattr(struct dentry *dentry)
 246 {
 247         struct inode *inode = dentry->d_inode;
 248         __u32 mask = FS_ATTRIB;
 249
 250         if (S_ISDIR(inode->i_mode))
 251                 mask |= FS_ISDIR;
 252
 253         fsnotify_parent(NULL, dentry, mask);
 254         fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
 255 }
 256
 257 /*
 258  * fsnotify_change - notify_change event.  file was modified and/or metadata
 259  * was changed.
 260  */
 261 static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
 262 {
 263         struct inode *inode = dentry->d_inode;
 264         __u32 mask = 0;
 265
 266         if (ia_valid & ATTR_UID)
 267                 mask |= FS_ATTRIB;
 268         if (ia_valid & ATTR_GID)
 269                 mask |= FS_ATTRIB;
 270         if (ia_valid & ATTR_SIZE)
 271                 mask |= FS_MODIFY;
 272
 273         /* both times implies a utime(s) call */
 274         if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
 275                 mask |= FS_ATTRIB;
 276         else if (ia_valid & ATTR_ATIME)
 277                 mask |= FS_ACCESS;
 278         else if (ia_valid & ATTR_MTIME)
 279                 mask |= FS_MODIFY;
 280
 281         if (ia_valid & ATTR_MODE)
 282                 mask |= FS_ATTRIB;
 283
 284         if (mask) {
 285                 if (S_ISDIR(inode->i_mode))
 286                         mask |= FS_ISDIR;
 287
 288                 fsnotify_parent(NULL, dentry, mask);
 289                 fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
 290         }
 291 }
 292
 293 #endif  /* _LINUX_FS_NOTIFY_H */