1 files changed, 395 insertions, 0 deletions
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
new file mode 100644
index 000000000..bb8467cd1
--- /dev/null
+++ b/include/linux/fsnotify.h
@@ -0,0 +1,395 @@
+/* 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>
+
+/*
+ * 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 (atomic_long_read(&dir->i_sb->s_fsnotify_connectors) == 0)
+		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 (atomic_long_read(&inode->i_sb->s_fsnotify_connectors) == 0)
+		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 (atomic_long_read(&inode->i_sb->s_fsnotify_connectors) == 0)
+		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 = &file->f_path;
+
+	if (file->f_mode & FMODE_NONOTIFY)
+		return 0;
+
+	return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
+}
+
+/* Simple call site for access decisions */
+static inline int fsnotify_perm(struct file *file, int mask)
+{
+	int ret;
+	__u32 fsnotify_mask = 0;
+
+	if (!(mask & (MAY_READ | MAY_OPEN)))
+		return 0;
+
+	if (mask & MAY_OPEN) {
+		fsnotify_mask = FS_OPEN_PERM;
+
+		if (file->f_flags & __FMODE_EXEC) {
+			ret = fsnotify_file(file, FS_OPEN_EXEC_PERM);
+
+			if (ret)
+				return ret;
+		}
+	} else if (mask & MAY_READ) {
+		fsnotify_mask = FS_ACCESS_PERM;
+	}
+
+	return fsnotify_file(file, fsnotify_mask);
+}
+
+/*
+ * 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 */