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 /*
  21  * Notify this @dir inode about a change in the directory entry @dentry.
  22  *
  23  * Unlike fsnotify_parent(), the event will be reported regardless of the
  24  * FS_EVENT_ON_CHILD mask on the parent inode.
  25  */
  26 static inline int fsnotify_dirent(struct inode *dir, struct dentry *dentry,
  27                                   __u32 mask)
  28 {
  29         return fsnotify(dir, mask, d_inode(dentry), FSNOTIFY_EVENT_INODE,
  30                         &dentry->d_name, 0);
  31 }
  32
  33 /* Notify this dentry's parent about a child's events. */
  34 static inline int fsnotify_parent(const struct path *path,
  35                                   struct dentry *dentry, __u32 mask)
  36 {
  37         if (!dentry)
  38                 dentry = path->dentry;
  39
  40         return __fsnotify_parent(path, dentry, mask);
  41 }
  42
  43 /*
  44  * Simple wrapper to consolidate calls fsnotify_parent()/fsnotify() when
  45  * an event is on a path.
  46  */
  47 static inline int fsnotify_path(struct inode *inode, const struct path *path,
  48                                 __u32 mask)
  49 {
  50         int ret = fsnotify_parent(path, NULL, mask);
  51
  52         if (ret)
  53                 return ret;
  54         return fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
  55 }
  56
  57 /* Simple call site for access decisions */
  58 static inline int fsnotify_perm(struct file *file, int mask)
  59 {
  60         int ret;
  61         const struct path *path = &file->f_path;
  62         struct inode *inode = file_inode(file);
  63         __u32 fsnotify_mask = 0;
  64
  65         if (file->f_mode & FMODE_NONOTIFY)
  66                 return 0;
  67         if (!(mask & (MAY_READ | MAY_OPEN)))
  68                 return 0;
  69         if (mask & MAY_OPEN) {
  70                 fsnotify_mask = FS_OPEN_PERM;
  71
  72                 if (file->f_flags & __FMODE_EXEC) {
  73                         ret = fsnotify_path(inode, path, FS_OPEN_EXEC_PERM);
  74
  75                         if (ret)
  76                                 return ret;
  77                 }
  78         } else if (mask & MAY_READ) {
  79                 fsnotify_mask = FS_ACCESS_PERM;
  80         }
  81
  82         if (S_ISDIR(inode->i_mode))
  83                 fsnotify_mask |= FS_ISDIR;
  84
  85         return fsnotify_path(inode, path, fsnotify_mask);
  86 }
  87
  88 /*
  89  * fsnotify_link_count - inode's link count changed
  90  */
  91 static inline void fsnotify_link_count(struct inode *inode)
  92 {
  93         __u32 mask = FS_ATTRIB;
  94
  95         if (S_ISDIR(inode->i_mode))
  96                 mask |= FS_ISDIR;
  97
  98         fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
  99 }
 100
 101 /*
 102  * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
 103  */
 104 static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
 105                                  const struct qstr *old_name,
 106                                  int isdir, struct inode *target,
 107                                  struct dentry *moved)
 108 {
 109         struct inode *source = moved->d_inode;
 110         u32 fs_cookie = fsnotify_get_cookie();
 111         __u32 old_dir_mask = FS_MOVED_FROM;
 112         __u32 new_dir_mask = FS_MOVED_TO;
 113         __u32 mask = FS_MOVE_SELF;
 114         const struct qstr *new_name = &moved->d_name;
 115
 116         if (old_dir == new_dir)
 117                 old_dir_mask |= FS_DN_RENAME;
 118
 119         if (isdir) {
 120                 old_dir_mask |= FS_ISDIR;
 121                 new_dir_mask |= FS_ISDIR;
 122                 mask |= FS_ISDIR;
 123         }
 124
 125         fsnotify(old_dir, old_dir_mask, source, FSNOTIFY_EVENT_INODE, old_name,
 126                  fs_cookie);
 127         fsnotify(new_dir, new_dir_mask, source, FSNOTIFY_EVENT_INODE, new_name,
 128                  fs_cookie);
 129
 130         if (target)
 131                 fsnotify_link_count(target);
 132
 133         if (source)
 134                 fsnotify(source, mask, source, FSNOTIFY_EVENT_INODE, NULL, 0);
 135         audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
 136 }
 137
 138 /*
 139  * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
 140  */
 141 static inline void fsnotify_inode_delete(struct inode *inode)
 142 {
 143         __fsnotify_inode_delete(inode);
 144 }
 145
 146 /*
 147  * fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
 148  */
 149 static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
 150 {
 151         __fsnotify_vfsmount_delete(mnt);
 152 }
 153
 154 /*
 155  * fsnotify_inoderemove - an inode is going away
 156  */
 157 static inline void fsnotify_inoderemove(struct inode *inode)
 158 {
 159         __u32 mask = FS_DELETE_SELF;
 160
 161         if (S_ISDIR(inode->i_mode))
 162                 mask |= FS_ISDIR;
 163
 164         fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
 165         __fsnotify_inode_delete(inode);
 166 }
 167
 168 /*
 169  * fsnotify_create - 'name' was linked in
 170  */
 171 static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
 172 {
 173         audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
 174
 175         fsnotify_dirent(inode, dentry, FS_CREATE);
 176 }
 177
 178 /*
 179  * fsnotify_link - new hardlink in 'inode' directory
 180  * Note: We have to pass also the linked inode ptr as some filesystems leave
 181  *   new_dentry->d_inode NULL and instantiate inode pointer later
 182  */
 183 static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct dentry *new_dentry)
 184 {
 185         fsnotify_link_count(inode);
 186         audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
 187
 188         fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, &new_dentry->d_name, 0);
 189 }
 190
 191 /*
 192  * fsnotify_mkdir - directory 'name' was created
 193  */
 194 static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 195 {
 196         audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
 197
 198         fsnotify_dirent(inode, dentry, FS_CREATE | FS_ISDIR);
 199 }
 200
 201 /*
 202  * fsnotify_access - file was read
 203  */
 204 static inline void fsnotify_access(struct file *file)
 205 {
 206         const struct path *path = &file->f_path;
 207         struct inode *inode = file_inode(file);
 208         __u32 mask = FS_ACCESS;
 209
 210         if (S_ISDIR(inode->i_mode))
 211                 mask |= FS_ISDIR;
 212
 213         if (!(file->f_mode & FMODE_NONOTIFY))
 214                 fsnotify_path(inode, path, mask);
 215 }
 216
 217 /*
 218  * fsnotify_modify - file was modified
 219  */
 220 static inline void fsnotify_modify(struct file *file)
 221 {
 222         const struct path *path = &file->f_path;
 223         struct inode *inode = file_inode(file);
 224         __u32 mask = FS_MODIFY;
 225
 226         if (S_ISDIR(inode->i_mode))
 227                 mask |= FS_ISDIR;
 228
 229         if (!(file->f_mode & FMODE_NONOTIFY))
 230                 fsnotify_path(inode, path, mask);
 231 }
 232
 233 /*
 234  * fsnotify_open - file was opened
 235  */
 236 static inline void fsnotify_open(struct file *file)
 237 {
 238         const struct path *path = &file->f_path;
 239         struct inode *inode = file_inode(file);
 240         __u32 mask = FS_OPEN;
 241
 242         if (S_ISDIR(inode->i_mode))
 243                 mask |= FS_ISDIR;
 244         if (file->f_flags & __FMODE_EXEC)
 245                 mask |= FS_OPEN_EXEC;
 246
 247         fsnotify_path(inode, path, mask);
 248 }
 249
 250 /*
 251  * fsnotify_close - file was closed
 252  */
 253 static inline void fsnotify_close(struct file *file)
 254 {
 255         const struct path *path = &file->f_path;
 256         struct inode *inode = file_inode(file);
 257         fmode_t mode = file->f_mode;
 258         __u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
 259
 260         if (S_ISDIR(inode->i_mode))
 261                 mask |= FS_ISDIR;
 262
 263         if (!(file->f_mode & FMODE_NONOTIFY))
 264                 fsnotify_path(inode, path, mask);
 265 }
 266
 267 /*
 268  * fsnotify_xattr - extended attributes were changed
 269  */
 270 static inline void fsnotify_xattr(struct dentry *dentry)
 271 {
 272         struct inode *inode = dentry->d_inode;
 273         __u32 mask = FS_ATTRIB;
 274
 275         if (S_ISDIR(inode->i_mode))
 276                 mask |= FS_ISDIR;
 277
 278         fsnotify_parent(NULL, dentry, mask);
 279         fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
 280 }
 281
 282 /*
 283  * fsnotify_change - notify_change event.  file was modified and/or metadata
 284  * was changed.
 285  */
 286 static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
 287 {
 288         struct inode *inode = dentry->d_inode;
 289         __u32 mask = 0;
 290
 291         if (ia_valid & ATTR_UID)
 292                 mask |= FS_ATTRIB;
 293         if (ia_valid & ATTR_GID)
 294                 mask |= FS_ATTRIB;
 295         if (ia_valid & ATTR_SIZE)
 296                 mask |= FS_MODIFY;
 297
 298         /* both times implies a utime(s) call */
 299         if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
 300                 mask |= FS_ATTRIB;
 301         else if (ia_valid & ATTR_ATIME)
 302                 mask |= FS_ACCESS;
 303         else if (ia_valid & ATTR_MTIME)
 304                 mask |= FS_MODIFY;
 305
 306         if (ia_valid & ATTR_MODE)
 307                 mask |= FS_ATTRIB;
 308
 309         if (mask) {
 310                 if (S_ISDIR(inode->i_mode))
 311                         mask |= FS_ISDIR;
 312
 313                 fsnotify_parent(NULL, dentry, mask);
 314                 fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
 315         }
 316 }
 317
 318 #endif  /* _LINUX_FS_NOTIFY_H */