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 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 void fsnotify_name(struct inode *dir, __u32 mask,
  30                                  struct inode *child,
  31                                  const struct qstr *name, u32 cookie)
  32 {
  33         fsnotify(mask, child, FSNOTIFY_EVENT_INODE, dir, name, NULL, cookie);
  34 }
  35
  36 static inline void fsnotify_dirent(struct inode *dir, struct dentry *dentry,
  37                                    __u32 mask)
  38 {
  39         fsnotify_name(dir, mask, d_inode(dentry), &dentry->d_name, 0);
  40 }
  41
  42 static inline void fsnotify_inode(struct inode *inode, __u32 mask)
  43 {
  44         if (S_ISDIR(inode->i_mode))
  45                 mask |= FS_ISDIR;
  46
  47         fsnotify(mask, inode, FSNOTIFY_EVENT_INODE, NULL, NULL, inode, 0);
  48 }
  49
  50 /* Notify this dentry's parent about a child's events. */
  51 static inline int fsnotify_parent(struct dentry *dentry, __u32 mask,
  52                                   const void *data, int data_type)
  53 {
  54         struct inode *inode = d_inode(dentry);
  55
  56         if (S_ISDIR(inode->i_mode)) {
  57                 mask |= FS_ISDIR;
  58
  59                 /* sb/mount marks are not interested in name of directory */
  60                 if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
  61                         goto notify_child;
  62         }
  63
  64         /* disconnected dentry cannot notify parent */
  65         if (IS_ROOT(dentry))
  66                 goto notify_child;
  67
  68         return __fsnotify_parent(dentry, mask, data, data_type);
  69
  70 notify_child:
  71         return fsnotify(mask, data, data_type, NULL, NULL, inode, 0);
  72 }
  73
  74 /*
  75  * Simple wrappers to consolidate calls to fsnotify_parent() when an event
  76  * is on a file/dentry.
  77  */
  78 static inline void fsnotify_dentry(struct dentry *dentry, __u32 mask)
  79 {
  80         fsnotify_parent(dentry, mask, d_inode(dentry), FSNOTIFY_EVENT_INODE);
  81 }
  82
  83 static inline int fsnotify_file(struct file *file, __u32 mask)
  84 {
  85         const struct path *path = &file->f_path;
  86
  87         if (file->f_mode & FMODE_NONOTIFY)
  88                 return 0;
  89
  90         return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
  91 }
  92
  93 /* Simple call site for access decisions */
  94 static inline int fsnotify_perm(struct file *file, int mask)
  95 {
  96         int ret;
  97         __u32 fsnotify_mask = 0;
  98
  99         if (!(mask & (MAY_READ | MAY_OPEN)))
 100                 return 0;
 101
 102         if (mask & MAY_OPEN) {
 103                 fsnotify_mask = FS_OPEN_PERM;
 104
 105                 if (file->f_flags & __FMODE_EXEC) {
 106                         ret = fsnotify_file(file, FS_OPEN_EXEC_PERM);
 107
 108                         if (ret)
 109                                 return ret;
 110                 }
 111         } else if (mask & MAY_READ) {
 112                 fsnotify_mask = FS_ACCESS_PERM;
 113         }
 114
 115         return fsnotify_file(file, fsnotify_mask);
 116 }
 117
 118 /*
 119  * fsnotify_link_count - inode's link count changed
 120  */
 121 static inline void fsnotify_link_count(struct inode *inode)
 122 {
 123         fsnotify_inode(inode, FS_ATTRIB);
 124 }
 125
 126 /*
 127  * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
 128  */
 129 static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
 130                                  const struct qstr *old_name,
 131                                  int isdir, struct inode *target,
 132                                  struct dentry *moved)
 133 {
 134         struct inode *source = moved->d_inode;
 135         u32 fs_cookie = fsnotify_get_cookie();
 136         __u32 old_dir_mask = FS_MOVED_FROM;
 137         __u32 new_dir_mask = FS_MOVED_TO;
 138         const struct qstr *new_name = &moved->d_name;
 139
 140         if (old_dir == new_dir)
 141                 old_dir_mask |= FS_DN_RENAME;
 142
 143         if (isdir) {
 144                 old_dir_mask |= FS_ISDIR;
 145                 new_dir_mask |= FS_ISDIR;
 146         }
 147
 148         fsnotify_name(old_dir, old_dir_mask, source, old_name, fs_cookie);
 149         fsnotify_name(new_dir, new_dir_mask, source, new_name, fs_cookie);
 150
 151         if (target)
 152                 fsnotify_link_count(target);
 153         fsnotify_inode(source, FS_MOVE_SELF);
 154         audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
 155 }
 156
 157 /*
 158  * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
 159  */
 160 static inline void fsnotify_inode_delete(struct inode *inode)
 161 {
 162         __fsnotify_inode_delete(inode);
 163 }
 164
 165 /*
 166  * fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
 167  */
 168 static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
 169 {
 170         __fsnotify_vfsmount_delete(mnt);
 171 }
 172
 173 /*
 174  * fsnotify_inoderemove - an inode is going away
 175  */
 176 static inline void fsnotify_inoderemove(struct inode *inode)
 177 {
 178         fsnotify_inode(inode, FS_DELETE_SELF);
 179         __fsnotify_inode_delete(inode);
 180 }
 181
 182 /*
 183  * fsnotify_create - 'name' was linked in
 184  */
 185 static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
 186 {
 187         audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
 188
 189         fsnotify_dirent(inode, dentry, FS_CREATE);
 190 }
 191
 192 /*
 193  * fsnotify_link - new hardlink in 'inode' directory
 194  * Note: We have to pass also the linked inode ptr as some filesystems leave
 195  *   new_dentry->d_inode NULL and instantiate inode pointer later
 196  */
 197 static inline void fsnotify_link(struct inode *dir, struct inode *inode,
 198                                  struct dentry *new_dentry)
 199 {
 200         fsnotify_link_count(inode);
 201         audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
 202
 203         fsnotify_name(dir, FS_CREATE, inode, &new_dentry->d_name, 0);
 204 }
 205
 206 /*
 207  * fsnotify_unlink - 'name' was unlinked
 208  *
 209  * Caller must make sure that dentry->d_name is stable.
 210  */
 211 static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry)
 212 {
 213         /* Expected to be called before d_delete() */
 214         WARN_ON_ONCE(d_is_negative(dentry));
 215
 216         fsnotify_dirent(dir, dentry, FS_DELETE);
 217 }
 218
 219 /*
 220  * fsnotify_mkdir - directory 'name' was created
 221  */
 222 static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 223 {
 224         audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
 225
 226         fsnotify_dirent(inode, dentry, FS_CREATE | FS_ISDIR);
 227 }
 228
 229 /*
 230  * fsnotify_rmdir - directory 'name' was removed
 231  *
 232  * Caller must make sure that dentry->d_name is stable.
 233  */
 234 static inline void fsnotify_rmdir(struct inode *dir, struct dentry *dentry)
 235 {
 236         /* Expected to be called before d_delete() */
 237         WARN_ON_ONCE(d_is_negative(dentry));
 238
 239         fsnotify_dirent(dir, dentry, FS_DELETE | FS_ISDIR);
 240 }
 241
 242 /*
 243  * fsnotify_access - file was read
 244  */
 245 static inline void fsnotify_access(struct file *file)
 246 {
 247         fsnotify_file(file, FS_ACCESS);
 248 }
 249
 250 /*
 251  * fsnotify_modify - file was modified
 252  */
 253 static inline void fsnotify_modify(struct file *file)
 254 {
 255         fsnotify_file(file, FS_MODIFY);
 256 }
 257
 258 /*
 259  * fsnotify_open - file was opened
 260  */
 261 static inline void fsnotify_open(struct file *file)
 262 {
 263         __u32 mask = FS_OPEN;
 264
 265         if (file->f_flags & __FMODE_EXEC)
 266                 mask |= FS_OPEN_EXEC;
 267
 268         fsnotify_file(file, mask);
 269 }
 270
 271 /*
 272  * fsnotify_close - file was closed
 273  */
 274 static inline void fsnotify_close(struct file *file)
 275 {
 276         __u32 mask = (file->f_mode & FMODE_WRITE) ? FS_CLOSE_WRITE :
 277                                                     FS_CLOSE_NOWRITE;
 278
 279         fsnotify_file(file, mask);
 280 }
 281
 282 /*
 283  * fsnotify_xattr - extended attributes were changed
 284  */
 285 static inline void fsnotify_xattr(struct dentry *dentry)
 286 {
 287         fsnotify_dentry(dentry, FS_ATTRIB);
 288 }
 289
 290 /*
 291  * fsnotify_change - notify_change event.  file was modified and/or metadata
 292  * was changed.
 293  */
 294 static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
 295 {
 296         __u32 mask = 0;
 297
 298         if (ia_valid & ATTR_UID)
 299                 mask |= FS_ATTRIB;
 300         if (ia_valid & ATTR_GID)
 301                 mask |= FS_ATTRIB;
 302         if (ia_valid & ATTR_SIZE)
 303                 mask |= FS_MODIFY;
 304
 305         /* both times implies a utime(s) call */
 306         if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
 307                 mask |= FS_ATTRIB;
 308         else if (ia_valid & ATTR_ATIME)
 309                 mask |= FS_ACCESS;
 310         else if (ia_valid & ATTR_MTIME)
 311                 mask |= FS_MODIFY;
 312
 313         if (ia_valid & ATTR_MODE)
 314                 mask |= FS_ATTRIB;
 315
 316         if (mask)
 317                 fsnotify_dentry(dentry, mask);
 318 }
 319
 320 #endif  /* _LINUX_FS_NOTIFY_H */