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         if (atomic_long_read(&dir->i_sb->s_fsnotify_connectors) == 0)
  34                 return;
  35
  36         fsnotify(mask, child, FSNOTIFY_EVENT_INODE, 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(dir, mask, d_inode(dentry), &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, d_inode(dentry), FSNOTIFY_EVENT_INODE);
  90 }
  91
  92 static inline int fsnotify_file(struct file *file, __u32 mask)
  93 {
  94         const struct path *path = &file->f_path;
  95
  96         if (file->f_mode & FMODE_NONOTIFY)
  97                 return 0;
  98
  99         return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
 100 }
 101
 102 /* Simple call site for access decisions */
 103 static inline int fsnotify_perm(struct file *file, int mask)
 104 {
 105         int ret;
 106         __u32 fsnotify_mask = 0;
 107
 108         if (!(mask & (MAY_READ | MAY_OPEN)))
 109                 return 0;
 110
 111         if (mask & MAY_OPEN) {
 112                 fsnotify_mask = FS_OPEN_PERM;
 113
 114                 if (file->f_flags & __FMODE_EXEC) {
 115                         ret = fsnotify_file(file, FS_OPEN_EXEC_PERM);
 116
 117                         if (ret)
 118                                 return ret;
 119                 }
 120         } else if (mask & MAY_READ) {
 121                 fsnotify_mask = FS_ACCESS_PERM;
 122         }
 123
 124         return fsnotify_file(file, fsnotify_mask);
 125 }
 126
 127 /*
 128  * fsnotify_link_count - inode's link count changed
 129  */
 130 static inline void fsnotify_link_count(struct inode *inode)
 131 {
 132         fsnotify_inode(inode, FS_ATTRIB);
 133 }
 134
 135 /*
 136  * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
 137  */
 138 static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
 139                                  const struct qstr *old_name,
 140                                  int isdir, struct inode *target,
 141                                  struct dentry *moved)
 142 {
 143         struct inode *source = moved->d_inode;
 144         u32 fs_cookie = fsnotify_get_cookie();
 145         __u32 old_dir_mask = FS_MOVED_FROM;
 146         __u32 new_dir_mask = FS_MOVED_TO;
 147         const struct qstr *new_name = &moved->d_name;
 148
 149         if (old_dir == new_dir)
 150                 old_dir_mask |= FS_DN_RENAME;
 151
 152         if (isdir) {
 153                 old_dir_mask |= FS_ISDIR;
 154                 new_dir_mask |= FS_ISDIR;
 155         }
 156
 157         fsnotify_name(old_dir, old_dir_mask, source, old_name, fs_cookie);
 158         fsnotify_name(new_dir, new_dir_mask, source, new_name, fs_cookie);
 159
 160         if (target)
 161                 fsnotify_link_count(target);
 162         fsnotify_inode(source, FS_MOVE_SELF);
 163         audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
 164 }
 165
 166 /*
 167  * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
 168  */
 169 static inline void fsnotify_inode_delete(struct inode *inode)
 170 {
 171         __fsnotify_inode_delete(inode);
 172 }
 173
 174 /*
 175  * fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
 176  */
 177 static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
 178 {
 179         __fsnotify_vfsmount_delete(mnt);
 180 }
 181
 182 /*
 183  * fsnotify_inoderemove - an inode is going away
 184  */
 185 static inline void fsnotify_inoderemove(struct inode *inode)
 186 {
 187         fsnotify_inode(inode, FS_DELETE_SELF);
 188         __fsnotify_inode_delete(inode);
 189 }
 190
 191 /*
 192  * fsnotify_create - 'name' was linked in
 193  */
 194 static inline void fsnotify_create(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);
 199 }
 200
 201 /*
 202  * fsnotify_link - new hardlink in 'inode' directory
 203  * Note: We have to pass also the linked inode ptr as some filesystems leave
 204  *   new_dentry->d_inode NULL and instantiate inode pointer later
 205  */
 206 static inline void fsnotify_link(struct inode *dir, struct inode *inode,
 207                                  struct dentry *new_dentry)
 208 {
 209         fsnotify_link_count(inode);
 210         audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
 211
 212         fsnotify_name(dir, FS_CREATE, inode, &new_dentry->d_name, 0);
 213 }
 214
 215 /*
 216  * fsnotify_unlink - 'name' was unlinked
 217  *
 218  * Caller must make sure that dentry->d_name is stable.
 219  */
 220 static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry)
 221 {
 222         /* Expected to be called before d_delete() */
 223         WARN_ON_ONCE(d_is_negative(dentry));
 224
 225         fsnotify_dirent(dir, dentry, FS_DELETE);
 226 }
 227
 228 /*
 229  * fsnotify_mkdir - directory 'name' was created
 230  */
 231 static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 232 {
 233         audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
 234
 235         fsnotify_dirent(inode, dentry, FS_CREATE | FS_ISDIR);
 236 }
 237
 238 /*
 239  * fsnotify_rmdir - directory 'name' was removed
 240  *
 241  * Caller must make sure that dentry->d_name is stable.
 242  */
 243 static inline void fsnotify_rmdir(struct inode *dir, struct dentry *dentry)
 244 {
 245         /* Expected to be called before d_delete() */
 246         WARN_ON_ONCE(d_is_negative(dentry));
 247
 248         fsnotify_dirent(dir, dentry, FS_DELETE | FS_ISDIR);
 249 }
 250
 251 /*
 252  * fsnotify_access - file was read
 253  */
 254 static inline void fsnotify_access(struct file *file)
 255 {
 256         fsnotify_file(file, FS_ACCESS);
 257 }
 258
 259 /*
 260  * fsnotify_modify - file was modified
 261  */
 262 static inline void fsnotify_modify(struct file *file)
 263 {
 264         fsnotify_file(file, FS_MODIFY);
 265 }
 266
 267 /*
 268  * fsnotify_open - file was opened
 269  */
 270 static inline void fsnotify_open(struct file *file)
 271 {
 272         __u32 mask = FS_OPEN;
 273
 274         if (file->f_flags & __FMODE_EXEC)
 275                 mask |= FS_OPEN_EXEC;
 276
 277         fsnotify_file(file, mask);
 278 }
 279
 280 /*
 281  * fsnotify_close - file was closed
 282  */
 283 static inline void fsnotify_close(struct file *file)
 284 {
 285         __u32 mask = (file->f_mode & FMODE_WRITE) ? FS_CLOSE_WRITE :
 286                                                     FS_CLOSE_NOWRITE;
 287
 288         fsnotify_file(file, mask);
 289 }
 290
 291 /*
 292  * fsnotify_xattr - extended attributes were changed
 293  */
 294 static inline void fsnotify_xattr(struct dentry *dentry)
 295 {
 296         fsnotify_dentry(dentry, FS_ATTRIB);
 297 }
 298
 299 /*
 300  * fsnotify_change - notify_change event.  file was modified and/or metadata
 301  * was changed.
 302  */
 303 static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
 304 {
 305         __u32 mask = 0;
 306
 307         if (ia_valid & ATTR_UID)
 308                 mask |= FS_ATTRIB;
 309         if (ia_valid & ATTR_GID)
 310                 mask |= FS_ATTRIB;
 311         if (ia_valid & ATTR_SIZE)
 312                 mask |= FS_MODIFY;
 313
 314         /* both times implies a utime(s) call */
 315         if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
 316                 mask |= FS_ATTRIB;
 317         else if (ia_valid & ATTR_ATIME)
 318                 mask |= FS_ACCESS;
 319         else if (ia_valid & ATTR_MTIME)
 320                 mask |= FS_MODIFY;
 321
 322         if (ia_valid & ATTR_MODE)
 323                 mask |= FS_ATTRIB;
 324
 325         if (mask)
 326                 fsnotify_dentry(dentry, mask);
 327 }
 328
 329 #endif  /* _LINUX_FS_NOTIFY_H */