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