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 a child directory entry. 22 * The directory entry may have turned positive or negative or its inode may 23 * have changed (i.e. renamed over). 24 * 25 * Unlike fsnotify_parent(), the event will be reported regardless of the 26 * FS_EVENT_ON_CHILD mask on the parent inode and will not be reported if only 27 * the child is interested and not the parent. 28 */ 29 static inline int fsnotify_name(__u32 mask, const void *data, int data_type, 30 struct inode *dir, const struct qstr *name, 31 u32 cookie) 32 { 33 if (atomic_long_read(&dir->i_sb->s_fsnotify_connectors) == 0) 34 return 0; 35 36 return fsnotify(mask, data, data_type, dir, name, NULL, cookie); 37 } 38 39 static inline void fsnotify_dirent(struct inode *dir, struct dentry *dentry, 40 __u32 mask) 41 { 42 fsnotify_name(mask, dentry, FSNOTIFY_EVENT_DENTRY, dir, &dentry->d_name, 0); 43 } 44 45 static inline void fsnotify_inode(struct inode *inode, __u32 mask) 46 { 47 if (atomic_long_read(&inode->i_sb->s_fsnotify_connectors) == 0) 48 return; 49 50 if (S_ISDIR(inode->i_mode)) 51 mask |= FS_ISDIR; 52 53 fsnotify(mask, inode, FSNOTIFY_EVENT_INODE, NULL, NULL, inode, 0); 54 } 55 56 /* Notify this dentry's parent about a child's events. */ 57 static inline int fsnotify_parent(struct dentry *dentry, __u32 mask, 58 const void *data, int data_type) 59 { 60 struct inode *inode = d_inode(dentry); 61 62 if (atomic_long_read(&inode->i_sb->s_fsnotify_connectors) == 0) 63 return 0; 64 65 if (S_ISDIR(inode->i_mode)) { 66 mask |= FS_ISDIR; 67 68 /* sb/mount marks are not interested in name of directory */ 69 if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) 70 goto notify_child; 71 } 72 73 /* disconnected dentry cannot notify parent */ 74 if (IS_ROOT(dentry)) 75 goto notify_child; 76 77 return __fsnotify_parent(dentry, mask, data, data_type); 78 79 notify_child: 80 return fsnotify(mask, data, data_type, NULL, NULL, inode, 0); 81 } 82 83 /* 84 * Simple wrappers to consolidate calls to fsnotify_parent() when an event 85 * is on a file/dentry. 86 */ 87 static inline void fsnotify_dentry(struct dentry *dentry, __u32 mask) 88 { 89 fsnotify_parent(dentry, mask, dentry, FSNOTIFY_EVENT_DENTRY); 90 } 91 92 static inline int fsnotify_file(struct file *file, __u32 mask) 93 { 94 const struct path *path; 95 96 if (file->f_mode & FMODE_NONOTIFY) 97 return 0; 98 99 /* Overlayfs internal files have fake f_path */ 100 path = file_real_path(file); 101 return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH); 102 } 103 104 /* Simple call site for access decisions */ 105 static inline int fsnotify_perm(struct file *file, int mask) 106 { 107 int ret; 108 __u32 fsnotify_mask = 0; 109 110 if (!(mask & (MAY_READ | MAY_OPEN))) 111 return 0; 112 113 if (mask & MAY_OPEN) { 114 fsnotify_mask = FS_OPEN_PERM; 115 116 if (file->f_flags & __FMODE_EXEC) { 117 ret = fsnotify_file(file, FS_OPEN_EXEC_PERM); 118 119 if (ret) 120 return ret; 121 } 122 } else if (mask & MAY_READ) { 123 fsnotify_mask = FS_ACCESS_PERM; 124 } 125 126 return fsnotify_file(file, fsnotify_mask); 127 } 128 129 /* 130 * fsnotify_link_count - inode's link count changed 131 */ 132 static inline void fsnotify_link_count(struct inode *inode) 133 { 134 fsnotify_inode(inode, FS_ATTRIB); 135 } 136 137 /* 138 * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir 139 */ 140 static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, 141 const struct qstr *old_name, 142 int isdir, struct inode *target, 143 struct dentry *moved) 144 { 145 struct inode *source = moved->d_inode; 146 u32 fs_cookie = fsnotify_get_cookie(); 147 __u32 old_dir_mask = FS_MOVED_FROM; 148 __u32 new_dir_mask = FS_MOVED_TO; 149 __u32 rename_mask = FS_RENAME; 150 const struct qstr *new_name = &moved->d_name; 151 152 if (isdir) { 153 old_dir_mask |= FS_ISDIR; 154 new_dir_mask |= FS_ISDIR; 155 rename_mask |= FS_ISDIR; 156 } 157 158 /* Event with information about both old and new parent+name */ 159 fsnotify_name(rename_mask, moved, FSNOTIFY_EVENT_DENTRY, 160 old_dir, old_name, 0); 161 162 fsnotify_name(old_dir_mask, source, FSNOTIFY_EVENT_INODE, 163 old_dir, old_name, fs_cookie); 164 fsnotify_name(new_dir_mask, source, FSNOTIFY_EVENT_INODE, 165 new_dir, new_name, fs_cookie); 166 167 if (target) 168 fsnotify_link_count(target); 169 fsnotify_inode(source, FS_MOVE_SELF); 170 audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE); 171 } 172 173 /* 174 * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed 175 */ 176 static inline void fsnotify_inode_delete(struct inode *inode) 177 { 178 __fsnotify_inode_delete(inode); 179 } 180 181 /* 182 * fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed 183 */ 184 static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt) 185 { 186 __fsnotify_vfsmount_delete(mnt); 187 } 188 189 /* 190 * fsnotify_inoderemove - an inode is going away 191 */ 192 static inline void fsnotify_inoderemove(struct inode *inode) 193 { 194 fsnotify_inode(inode, FS_DELETE_SELF); 195 __fsnotify_inode_delete(inode); 196 } 197 198 /* 199 * fsnotify_create - 'name' was linked in 200 * 201 * Caller must make sure that dentry->d_name is stable. 202 * Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate 203 * ->d_inode later 204 */ 205 static inline void fsnotify_create(struct inode *dir, struct dentry *dentry) 206 { 207 audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE); 208 209 fsnotify_dirent(dir, dentry, FS_CREATE); 210 } 211 212 /* 213 * fsnotify_link - new hardlink in 'inode' directory 214 * 215 * Caller must make sure that new_dentry->d_name is stable. 216 * Note: We have to pass also the linked inode ptr as some filesystems leave 217 * new_dentry->d_inode NULL and instantiate inode pointer later 218 */ 219 static inline void fsnotify_link(struct inode *dir, struct inode *inode, 220 struct dentry *new_dentry) 221 { 222 fsnotify_link_count(inode); 223 audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE); 224 225 fsnotify_name(FS_CREATE, inode, FSNOTIFY_EVENT_INODE, 226 dir, &new_dentry->d_name, 0); 227 } 228 229 /* 230 * fsnotify_delete - @dentry was unlinked and unhashed 231 * 232 * Caller must make sure that dentry->d_name is stable. 233 * 234 * Note: unlike fsnotify_unlink(), we have to pass also the unlinked inode 235 * as this may be called after d_delete() and old_dentry may be negative. 236 */ 237 static inline void fsnotify_delete(struct inode *dir, struct inode *inode, 238 struct dentry *dentry) 239 { 240 __u32 mask = FS_DELETE; 241 242 if (S_ISDIR(inode->i_mode)) 243 mask |= FS_ISDIR; 244 245 fsnotify_name(mask, inode, FSNOTIFY_EVENT_INODE, dir, &dentry->d_name, 246 0); 247 } 248 249 /** 250 * d_delete_notify - delete a dentry and call fsnotify_delete() 251 * @dentry: The dentry to delete 252 * 253 * This helper is used to guaranty that the unlinked inode cannot be found 254 * by lookup of this name after fsnotify_delete() event has been delivered. 255 */ 256 static inline void d_delete_notify(struct inode *dir, struct dentry *dentry) 257 { 258 struct inode *inode = d_inode(dentry); 259 260 ihold(inode); 261 d_delete(dentry); 262 fsnotify_delete(dir, inode, dentry); 263 iput(inode); 264 } 265 266 /* 267 * fsnotify_unlink - 'name' was unlinked 268 * 269 * Caller must make sure that dentry->d_name is stable. 270 */ 271 static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry) 272 { 273 if (WARN_ON_ONCE(d_is_negative(dentry))) 274 return; 275 276 fsnotify_delete(dir, d_inode(dentry), dentry); 277 } 278 279 /* 280 * fsnotify_mkdir - directory 'name' was created 281 * 282 * Caller must make sure that dentry->d_name is stable. 283 * Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate 284 * ->d_inode later 285 */ 286 static inline void fsnotify_mkdir(struct inode *dir, struct dentry *dentry) 287 { 288 audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE); 289 290 fsnotify_dirent(dir, dentry, FS_CREATE | FS_ISDIR); 291 } 292 293 /* 294 * fsnotify_rmdir - directory 'name' was removed 295 * 296 * Caller must make sure that dentry->d_name is stable. 297 */ 298 static inline void fsnotify_rmdir(struct inode *dir, struct dentry *dentry) 299 { 300 if (WARN_ON_ONCE(d_is_negative(dentry))) 301 return; 302 303 fsnotify_delete(dir, d_inode(dentry), dentry); 304 } 305 306 /* 307 * fsnotify_access - file was read 308 */ 309 static inline void fsnotify_access(struct file *file) 310 { 311 fsnotify_file(file, FS_ACCESS); 312 } 313 314 /* 315 * fsnotify_modify - file was modified 316 */ 317 static inline void fsnotify_modify(struct file *file) 318 { 319 fsnotify_file(file, FS_MODIFY); 320 } 321 322 /* 323 * fsnotify_open - file was opened 324 */ 325 static inline void fsnotify_open(struct file *file) 326 { 327 __u32 mask = FS_OPEN; 328 329 if (file->f_flags & __FMODE_EXEC) 330 mask |= FS_OPEN_EXEC; 331 332 fsnotify_file(file, mask); 333 } 334 335 /* 336 * fsnotify_close - file was closed 337 */ 338 static inline void fsnotify_close(struct file *file) 339 { 340 __u32 mask = (file->f_mode & FMODE_WRITE) ? FS_CLOSE_WRITE : 341 FS_CLOSE_NOWRITE; 342 343 fsnotify_file(file, mask); 344 } 345 346 /* 347 * fsnotify_xattr - extended attributes were changed 348 */ 349 static inline void fsnotify_xattr(struct dentry *dentry) 350 { 351 fsnotify_dentry(dentry, FS_ATTRIB); 352 } 353 354 /* 355 * fsnotify_change - notify_change event. file was modified and/or metadata 356 * was changed. 357 */ 358 static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid) 359 { 360 __u32 mask = 0; 361 362 if (ia_valid & ATTR_UID) 363 mask |= FS_ATTRIB; 364 if (ia_valid & ATTR_GID) 365 mask |= FS_ATTRIB; 366 if (ia_valid & ATTR_SIZE) 367 mask |= FS_MODIFY; 368 369 /* both times implies a utime(s) call */ 370 if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME)) 371 mask |= FS_ATTRIB; 372 else if (ia_valid & ATTR_ATIME) 373 mask |= FS_ACCESS; 374 else if (ia_valid & ATTR_MTIME) 375 mask |= FS_MODIFY; 376 377 if (ia_valid & ATTR_MODE) 378 mask |= FS_ATTRIB; 379 380 if (mask) 381 fsnotify_dentry(dentry, mask); 382 } 383 384 static inline int fsnotify_sb_error(struct super_block *sb, struct inode *inode, 385 int error) 386 { 387 struct fs_error_report report = { 388 .error = error, 389 .inode = inode, 390 .sb = sb, 391 }; 392 393 return fsnotify(FS_ERROR, &report, FSNOTIFY_EVENT_ERROR, 394 NULL, NULL, NULL, 0); 395 } 396 397 #endif /* _LINUX_FS_NOTIFY_H */ 398