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_delete - @dentry was unlinked and unhashed
 193  *
 194  * Caller must make sure that dentry->d_name is stable.
 195  *
 196  * Note: unlike fsnotify_unlink(), we have to pass also the unlinked inode
 197  * as this may be called after d_delete() and old_dentry may be negative.
 198  */
 199 static inline void fsnotify_delete(struct inode *dir, struct inode *inode,
 200                                    struct dentry *dentry)
 201 {
 202         __u32 mask = FS_DELETE;
 203
 204         if (S_ISDIR(inode->i_mode))
 205                 mask |= FS_ISDIR;
 206
 207         fsnotify(dir, mask, inode, FSNOTIFY_EVENT_INODE, &dentry->d_name, 0);
 208 }
 209
 210 /**
 211  * d_delete_notify - delete a dentry and call fsnotify_delete()
 212  * @dentry: The dentry to delete
 213  *
 214  * This helper is used to guaranty that the unlinked inode cannot be found
 215  * by lookup of this name after fsnotify_delete() event has been delivered.
 216  */
 217 static inline void d_delete_notify(struct inode *dir, struct dentry *dentry)
 218 {
 219         struct inode *inode = d_inode(dentry);
 220
 221         ihold(inode);
 222         d_delete(dentry);
 223         fsnotify_delete(dir, inode, dentry);
 224         iput(inode);
 225 }
 226
 227 /*
 228  * fsnotify_unlink - 'name' was unlinked
 229  *
 230  * Caller must make sure that dentry->d_name is stable.
 231  */
 232 static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry)
 233 {
 234         if (WARN_ON_ONCE(d_is_negative(dentry)))
 235                 return;
 236
 237         fsnotify_delete(dir, d_inode(dentry), dentry);
 238 }
 239
 240 /*
 241  * fsnotify_mkdir - directory 'name' was created
 242  */
 243 static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 244 {
 245         audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
 246
 247         fsnotify_dirent(inode, dentry, FS_CREATE | FS_ISDIR);
 248 }
 249
 250 /*
 251  * fsnotify_rmdir - directory 'name' was removed
 252  *
 253  * Caller must make sure that dentry->d_name is stable.
 254  */
 255 static inline void fsnotify_rmdir(struct inode *dir, struct dentry *dentry)
 256 {
 257         if (WARN_ON_ONCE(d_is_negative(dentry)))
 258                 return;
 259
 260         fsnotify_delete(dir, d_inode(dentry), dentry);
 261 }
 262
 263 /*
 264  * fsnotify_access - file was read
 265  */
 266 static inline void fsnotify_access(struct file *file)
 267 {
 268         const struct path *path = &file->f_path;
 269         struct inode *inode = file_inode(file);
 270         __u32 mask = FS_ACCESS;
 271
 272         if (S_ISDIR(inode->i_mode))
 273                 mask |= FS_ISDIR;
 274
 275         if (!(file->f_mode & FMODE_NONOTIFY))
 276                 fsnotify_path(inode, path, mask);
 277 }
 278
 279 /*
 280  * fsnotify_modify - file was modified
 281  */
 282 static inline void fsnotify_modify(struct file *file)
 283 {
 284         const struct path *path = &file->f_path;
 285         struct inode *inode = file_inode(file);
 286         __u32 mask = FS_MODIFY;
 287
 288         if (S_ISDIR(inode->i_mode))
 289                 mask |= FS_ISDIR;
 290
 291         if (!(file->f_mode & FMODE_NONOTIFY))
 292                 fsnotify_path(inode, path, mask);
 293 }
 294
 295 /*
 296  * fsnotify_open - file was opened
 297  */
 298 static inline void fsnotify_open(struct file *file)
 299 {
 300         const struct path *path = &file->f_path;
 301         struct inode *inode = file_inode(file);
 302         __u32 mask = FS_OPEN;
 303
 304         if (S_ISDIR(inode->i_mode))
 305                 mask |= FS_ISDIR;
 306         if (file->f_flags & __FMODE_EXEC)
 307                 mask |= FS_OPEN_EXEC;
 308
 309         fsnotify_path(inode, path, mask);
 310 }
 311
 312 /*
 313  * fsnotify_close - file was closed
 314  */
 315 static inline void fsnotify_close(struct file *file)
 316 {
 317         const struct path *path = &file->f_path;
 318         struct inode *inode = file_inode(file);
 319         fmode_t mode = file->f_mode;
 320         __u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
 321
 322         if (S_ISDIR(inode->i_mode))
 323                 mask |= FS_ISDIR;
 324
 325         if (!(file->f_mode & FMODE_NONOTIFY))
 326                 fsnotify_path(inode, path, mask);
 327 }
 328
 329 /*
 330  * fsnotify_xattr - extended attributes were changed
 331  */
 332 static inline void fsnotify_xattr(struct dentry *dentry)
 333 {
 334         struct inode *inode = dentry->d_inode;
 335         __u32 mask = FS_ATTRIB;
 336
 337         if (S_ISDIR(inode->i_mode))
 338                 mask |= FS_ISDIR;
 339
 340         fsnotify_parent(NULL, dentry, mask);
 341         fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
 342 }
 343
 344 /*
 345  * fsnotify_change - notify_change event.  file was modified and/or metadata
 346  * was changed.
 347  */
 348 static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
 349 {
 350         struct inode *inode = dentry->d_inode;
 351         __u32 mask = 0;
 352
 353         if (ia_valid & ATTR_UID)
 354                 mask |= FS_ATTRIB;
 355         if (ia_valid & ATTR_GID)
 356                 mask |= FS_ATTRIB;
 357         if (ia_valid & ATTR_SIZE)
 358                 mask |= FS_MODIFY;
 359
 360         /* both times implies a utime(s) call */
 361         if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
 362                 mask |= FS_ATTRIB;
 363         else if (ia_valid & ATTR_ATIME)
 364                 mask |= FS_ACCESS;
 365         else if (ia_valid & ATTR_MTIME)
 366                 mask |= FS_MODIFY;
 367
 368         if (ia_valid & ATTR_MODE)
 369                 mask |= FS_ATTRIB;
 370
 371         if (mask) {
 372                 if (S_ISDIR(inode->i_mode))
 373                         mask |= FS_ISDIR;
 374
 375                 fsnotify_parent(NULL, dentry, mask);
 376                 fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
 377         }
 378 }
 379
 380 #endif  /* _LINUX_FS_NOTIFY_H */