442 lines
11 KiB
C
442 lines
11 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_FS_NOTIFY_H
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#define _LINUX_FS_NOTIFY_H
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/*
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* include/linux/fsnotify.h - generic hooks for filesystem notification, to
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* reduce in-source duplication from both dnotify and inotify.
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*
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* We don't compile any of this away in some complicated menagerie of ifdefs.
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* Instead, we rely on the code inside to optimize away as needed.
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*
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* (C) Copyright 2005 Robert Love
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*/
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#include <linux/fsnotify_backend.h>
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#include <linux/audit.h>
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#include <linux/slab.h>
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#include <linux/bug.h>
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/* Are there any inode/mount/sb objects that are being watched at all? */
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static inline bool fsnotify_sb_has_watchers(struct super_block *sb)
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{
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return atomic_long_read(&sb->s_fsnotify_connectors);
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}
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/*
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* Notify this @dir inode about a change in a child directory entry.
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* The directory entry may have turned positive or negative or its inode may
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* have changed (i.e. renamed over).
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*
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* Unlike fsnotify_parent(), the event will be reported regardless of the
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* FS_EVENT_ON_CHILD mask on the parent inode and will not be reported if only
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* the child is interested and not the parent.
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*/
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static inline int fsnotify_name(__u32 mask, const void *data, int data_type,
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struct inode *dir, const struct qstr *name,
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u32 cookie)
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{
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if (!fsnotify_sb_has_watchers(dir->i_sb))
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return 0;
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return fsnotify(mask, data, data_type, dir, name, NULL, cookie);
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}
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static inline void fsnotify_dirent(struct inode *dir, struct dentry *dentry,
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__u32 mask)
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{
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fsnotify_name(mask, dentry, FSNOTIFY_EVENT_DENTRY, dir, &dentry->d_name, 0);
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}
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static inline void fsnotify_inode(struct inode *inode, __u32 mask)
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{
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if (!fsnotify_sb_has_watchers(inode->i_sb))
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return;
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if (S_ISDIR(inode->i_mode))
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mask |= FS_ISDIR;
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fsnotify(mask, inode, FSNOTIFY_EVENT_INODE, NULL, NULL, inode, 0);
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}
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/* Notify this dentry's parent about a child's events. */
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static inline int fsnotify_parent(struct dentry *dentry, __u32 mask,
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const void *data, int data_type)
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{
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struct inode *inode = d_inode(dentry);
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if (!fsnotify_sb_has_watchers(inode->i_sb))
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return 0;
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if (S_ISDIR(inode->i_mode)) {
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mask |= FS_ISDIR;
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/* sb/mount marks are not interested in name of directory */
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if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
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goto notify_child;
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}
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/* disconnected dentry cannot notify parent */
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if (IS_ROOT(dentry))
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goto notify_child;
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return __fsnotify_parent(dentry, mask, data, data_type);
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notify_child:
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return fsnotify(mask, data, data_type, NULL, NULL, inode, 0);
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}
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/*
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* Simple wrappers to consolidate calls to fsnotify_parent() when an event
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* is on a file/dentry.
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*/
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static inline void fsnotify_dentry(struct dentry *dentry, __u32 mask)
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{
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fsnotify_parent(dentry, mask, dentry, FSNOTIFY_EVENT_DENTRY);
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}
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static inline int fsnotify_file(struct file *file, __u32 mask)
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{
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const struct path *path;
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if (file->f_mode & FMODE_NONOTIFY)
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return 0;
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path = &file->f_path;
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return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
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}
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#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
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/*
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* fsnotify_file_area_perm - permission hook before access to file range
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*/
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static inline int fsnotify_file_area_perm(struct file *file, int perm_mask,
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const loff_t *ppos, size_t count)
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{
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__u32 fsnotify_mask = FS_ACCESS_PERM;
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/*
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* filesystem may be modified in the context of permission events
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* (e.g. by HSM filling a file on access), so sb freeze protection
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* must not be held.
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*/
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lockdep_assert_once(file_write_not_started(file));
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if (!(perm_mask & MAY_READ))
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return 0;
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return fsnotify_file(file, fsnotify_mask);
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}
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/*
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* fsnotify_file_perm - permission hook before file access
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*/
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static inline int fsnotify_file_perm(struct file *file, int perm_mask)
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{
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return fsnotify_file_area_perm(file, perm_mask, NULL, 0);
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}
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/*
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* fsnotify_open_perm - permission hook before file open
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*/
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static inline int fsnotify_open_perm(struct file *file)
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{
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int ret;
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if (file->f_flags & __FMODE_EXEC) {
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ret = fsnotify_file(file, FS_OPEN_EXEC_PERM);
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if (ret)
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return ret;
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}
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return fsnotify_file(file, FS_OPEN_PERM);
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}
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#else
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static inline int fsnotify_file_area_perm(struct file *file, int perm_mask,
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const loff_t *ppos, size_t count)
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{
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return 0;
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}
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static inline int fsnotify_file_perm(struct file *file, int perm_mask)
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{
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return 0;
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}
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static inline int fsnotify_open_perm(struct file *file)
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{
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return 0;
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}
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#endif
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/*
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* fsnotify_link_count - inode's link count changed
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*/
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static inline void fsnotify_link_count(struct inode *inode)
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{
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fsnotify_inode(inode, FS_ATTRIB);
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}
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/*
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* fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
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*/
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static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
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const struct qstr *old_name,
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int isdir, struct inode *target,
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struct dentry *moved)
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{
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struct inode *source = moved->d_inode;
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u32 fs_cookie = fsnotify_get_cookie();
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__u32 old_dir_mask = FS_MOVED_FROM;
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__u32 new_dir_mask = FS_MOVED_TO;
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__u32 rename_mask = FS_RENAME;
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const struct qstr *new_name = &moved->d_name;
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if (isdir) {
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old_dir_mask |= FS_ISDIR;
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new_dir_mask |= FS_ISDIR;
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rename_mask |= FS_ISDIR;
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}
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/* Event with information about both old and new parent+name */
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fsnotify_name(rename_mask, moved, FSNOTIFY_EVENT_DENTRY,
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old_dir, old_name, 0);
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fsnotify_name(old_dir_mask, source, FSNOTIFY_EVENT_INODE,
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old_dir, old_name, fs_cookie);
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fsnotify_name(new_dir_mask, source, FSNOTIFY_EVENT_INODE,
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new_dir, new_name, fs_cookie);
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if (target)
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fsnotify_link_count(target);
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fsnotify_inode(source, FS_MOVE_SELF);
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audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
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}
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/*
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* fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
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*/
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static inline void fsnotify_inode_delete(struct inode *inode)
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{
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__fsnotify_inode_delete(inode);
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}
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/*
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* fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
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*/
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static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
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{
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__fsnotify_vfsmount_delete(mnt);
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}
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/*
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* fsnotify_inoderemove - an inode is going away
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*/
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static inline void fsnotify_inoderemove(struct inode *inode)
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{
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fsnotify_inode(inode, FS_DELETE_SELF);
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__fsnotify_inode_delete(inode);
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}
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/*
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* fsnotify_create - 'name' was linked in
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*
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* Caller must make sure that dentry->d_name is stable.
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* Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate
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* ->d_inode later
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*/
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static inline void fsnotify_create(struct inode *dir, struct dentry *dentry)
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{
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audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE);
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fsnotify_dirent(dir, dentry, FS_CREATE);
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}
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/*
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* fsnotify_link - new hardlink in 'inode' directory
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*
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* Caller must make sure that new_dentry->d_name is stable.
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* Note: We have to pass also the linked inode ptr as some filesystems leave
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* new_dentry->d_inode NULL and instantiate inode pointer later
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*/
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static inline void fsnotify_link(struct inode *dir, struct inode *inode,
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struct dentry *new_dentry)
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{
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fsnotify_link_count(inode);
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audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
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fsnotify_name(FS_CREATE, inode, FSNOTIFY_EVENT_INODE,
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dir, &new_dentry->d_name, 0);
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}
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/*
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* fsnotify_delete - @dentry was unlinked and unhashed
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*
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* Caller must make sure that dentry->d_name is stable.
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*
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* Note: unlike fsnotify_unlink(), we have to pass also the unlinked inode
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* as this may be called after d_delete() and old_dentry may be negative.
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*/
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static inline void fsnotify_delete(struct inode *dir, struct inode *inode,
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struct dentry *dentry)
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{
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__u32 mask = FS_DELETE;
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if (S_ISDIR(inode->i_mode))
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mask |= FS_ISDIR;
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fsnotify_name(mask, inode, FSNOTIFY_EVENT_INODE, dir, &dentry->d_name,
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0);
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}
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/**
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* d_delete_notify - delete a dentry and call fsnotify_delete()
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* @dentry: The dentry to delete
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*
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* This helper is used to guaranty that the unlinked inode cannot be found
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* by lookup of this name after fsnotify_delete() event has been delivered.
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*/
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static inline void d_delete_notify(struct inode *dir, struct dentry *dentry)
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{
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struct inode *inode = d_inode(dentry);
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ihold(inode);
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d_delete(dentry);
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fsnotify_delete(dir, inode, dentry);
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iput(inode);
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}
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/*
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* fsnotify_unlink - 'name' was unlinked
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*
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* Caller must make sure that dentry->d_name is stable.
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*/
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static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry)
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{
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if (WARN_ON_ONCE(d_is_negative(dentry)))
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return;
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fsnotify_delete(dir, d_inode(dentry), dentry);
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}
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/*
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* fsnotify_mkdir - directory 'name' was created
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*
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* Caller must make sure that dentry->d_name is stable.
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* Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate
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* ->d_inode later
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*/
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static inline void fsnotify_mkdir(struct inode *dir, struct dentry *dentry)
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{
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audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE);
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fsnotify_dirent(dir, dentry, FS_CREATE | FS_ISDIR);
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}
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/*
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* fsnotify_rmdir - directory 'name' was removed
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*
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* Caller must make sure that dentry->d_name is stable.
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*/
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static inline void fsnotify_rmdir(struct inode *dir, struct dentry *dentry)
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{
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if (WARN_ON_ONCE(d_is_negative(dentry)))
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return;
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fsnotify_delete(dir, d_inode(dentry), dentry);
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}
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/*
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* fsnotify_access - file was read
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*/
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static inline void fsnotify_access(struct file *file)
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{
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fsnotify_file(file, FS_ACCESS);
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}
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/*
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* fsnotify_modify - file was modified
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*/
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static inline void fsnotify_modify(struct file *file)
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{
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fsnotify_file(file, FS_MODIFY);
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}
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/*
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* fsnotify_open - file was opened
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*/
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static inline void fsnotify_open(struct file *file)
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{
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__u32 mask = FS_OPEN;
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if (file->f_flags & __FMODE_EXEC)
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mask |= FS_OPEN_EXEC;
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fsnotify_file(file, mask);
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}
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/*
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* fsnotify_close - file was closed
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*/
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static inline void fsnotify_close(struct file *file)
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{
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__u32 mask = (file->f_mode & FMODE_WRITE) ? FS_CLOSE_WRITE :
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FS_CLOSE_NOWRITE;
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fsnotify_file(file, mask);
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}
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/*
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* fsnotify_xattr - extended attributes were changed
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*/
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static inline void fsnotify_xattr(struct dentry *dentry)
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{
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fsnotify_dentry(dentry, FS_ATTRIB);
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}
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/*
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* fsnotify_change - notify_change event. file was modified and/or metadata
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* was changed.
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*/
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static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
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{
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__u32 mask = 0;
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if (ia_valid & ATTR_UID)
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mask |= FS_ATTRIB;
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if (ia_valid & ATTR_GID)
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mask |= FS_ATTRIB;
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if (ia_valid & ATTR_SIZE)
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mask |= FS_MODIFY;
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/* both times implies a utime(s) call */
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if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
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mask |= FS_ATTRIB;
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else if (ia_valid & ATTR_ATIME)
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mask |= FS_ACCESS;
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else if (ia_valid & ATTR_MTIME)
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mask |= FS_MODIFY;
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if (ia_valid & ATTR_MODE)
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mask |= FS_ATTRIB;
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if (mask)
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fsnotify_dentry(dentry, mask);
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}
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static inline int fsnotify_sb_error(struct super_block *sb, struct inode *inode,
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int error)
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{
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struct fs_error_report report = {
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.error = error,
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.inode = inode,
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.sb = sb,
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};
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return fsnotify(FS_ERROR, &report, FSNOTIFY_EVENT_ERROR,
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NULL, NULL, NULL, 0);
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}
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#endif /* _LINUX_FS_NOTIFY_H */
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