/* SPDX-License-Identifier: GPL-2.0 */


#ifndef __LINUX_FSNOTIFY_BACKEND_H
#define __LINUX_FSNOTIFY_BACKEND_H

#ifdef __KERNEL__

#include <linux/idr.h> 
#include <linux/fs.h> 
#include <linux/list.h>
#include <linux/path.h> 
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/atomic.h>
#include <linux/user_namespace.h>
#include <linux/refcount.h>
#include <linux/mempool.h>
#include <linux/sched/mm.h>


#define FS_ACCESS		0x00000001	
#define FS_MODIFY		0x00000002	
#define FS_ATTRIB		0x00000004	
#define FS_CLOSE_WRITE		0x00000008	
#define FS_CLOSE_NOWRITE	0x00000010	
#define FS_OPEN			0x00000020	
#define FS_MOVED_FROM		0x00000040	
#define FS_MOVED_TO		0x00000080	
#define FS_CREATE		0x00000100	
#define FS_DELETE		0x00000200	
#define FS_DELETE_SELF		0x00000400	
#define FS_MOVE_SELF		0x00000800	
#define FS_OPEN_EXEC		0x00001000	

#define FS_UNMOUNT		0x00002000	
#define FS_Q_OVERFLOW		0x00004000	
#define FS_ERROR		0x00008000	


#define FS_IN_IGNORED		0x00008000	

#define FS_OPEN_PERM		0x00010000	
#define FS_ACCESS_PERM		0x00020000	
#define FS_OPEN_EXEC_PERM	0x00040000	


#define FS_EVENT_ON_CHILD	0x08000000

#define FS_RENAME		0x10000000	
#define FS_DN_MULTISHOT		0x20000000	
#define FS_ISDIR		0x40000000	

#define FS_MOVE			(FS_MOVED_FROM | FS_MOVED_TO)


#define ALL_FSNOTIFY_DIRENT_EVENTS (FS_CREATE | FS_DELETE | FS_MOVE | FS_RENAME)

#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM | \
				  FS_OPEN_EXEC_PERM)


#define FS_EVENTS_POSS_ON_CHILD   (ALL_FSNOTIFY_PERM_EVENTS | \
				   FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
				   FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | \
				   FS_OPEN | FS_OPEN_EXEC)


#define FS_EVENTS_POSS_TO_PARENT (FS_EVENTS_POSS_ON_CHILD)


#define ALL_FSNOTIFY_EVENTS (ALL_FSNOTIFY_DIRENT_EVENTS | \
			     FS_EVENTS_POSS_ON_CHILD | \
			     FS_DELETE_SELF | FS_MOVE_SELF | \
			     FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
			     FS_ERROR)


#define ALL_FSNOTIFY_FLAGS  (FS_ISDIR | FS_EVENT_ON_CHILD | FS_DN_MULTISHOT)

#define ALL_FSNOTIFY_BITS   (ALL_FSNOTIFY_EVENTS | ALL_FSNOTIFY_FLAGS)

struct fsnotify_group;
struct fsnotify_event;
struct fsnotify_mark;
struct fsnotify_event_private_data;
struct fsnotify_fname;
struct fsnotify_iter_info;

struct mem_cgroup;


struct fsnotify_ops {
	int (*handle_event)(struct fsnotify_group *group, u32 mask,
			    const void *data, int data_type, struct inode *dir,
			    const struct qstr *file_name, u32 cookie,
			    struct fsnotify_iter_info *iter_info);
	int (*handle_inode_event)(struct fsnotify_mark *mark, u32 mask,
			    struct inode *inode, struct inode *dir,
			    const struct qstr *file_name, u32 cookie);
	void (*free_group_priv)(struct fsnotify_group *group);
	void (*freeing_mark)(struct fsnotify_mark *mark, struct fsnotify_group *group);
	void (*free_event)(struct fsnotify_group *group, struct fsnotify_event *event);
	
	void (*free_mark)(struct fsnotify_mark *mark);
};


struct fsnotify_event {
	struct list_head list;
};


struct fsnotify_group {
	const struct fsnotify_ops *ops;	

	
	refcount_t refcnt;		

	
	spinlock_t notification_lock;		
	struct list_head notification_list;	
	wait_queue_head_t notification_waitq;	
	unsigned int q_len;			
	unsigned int max_events;		
	
	#define FS_PRIO_0	0 
	#define FS_PRIO_1	1 
	#define FS_PRIO_2	2 
	unsigned int priority;
	bool shutdown;		

#define FSNOTIFY_GROUP_USER	0x01 
#define FSNOTIFY_GROUP_DUPS	0x02 
#define FSNOTIFY_GROUP_NOFS	0x04 
	int flags;
	unsigned int owner_flags;	

	
	struct mutex mark_mutex;	
	atomic_t user_waits;		
	struct list_head marks_list;	

	struct fasync_struct *fsn_fa;    

	struct fsnotify_event *overflow_event;	

	struct mem_cgroup *memcg;	

	
	union {
		void *private;
#ifdef CONFIG_INOTIFY_USER
		struct inotify_group_private_data {
			spinlock_t	idr_lock;
			struct idr      idr;
			struct ucounts *ucounts;
		} inotify_data;
#endif
#ifdef CONFIG_FANOTIFY
		struct fanotify_group_private_data {
			
			struct hlist_head *merge_hash;
			
			struct list_head access_list;
			wait_queue_head_t access_waitq;
			int flags;           
			int f_flags; 
			struct ucounts *ucounts;
			mempool_t error_events_pool;
		} fanotify_data;
#endif 
	};
};


static inline void fsnotify_group_lock(struct fsnotify_group *group)
{
	mutex_lock(&group->mark_mutex);
	if (group->flags & FSNOTIFY_GROUP_NOFS)
		group->owner_flags = memalloc_nofs_save();
}

static inline void fsnotify_group_unlock(struct fsnotify_group *group)
{
	if (group->flags & FSNOTIFY_GROUP_NOFS)
		memalloc_nofs_restore(group->owner_flags);
	mutex_unlock(&group->mark_mutex);
}

static inline void fsnotify_group_assert_locked(struct fsnotify_group *group)
{
	WARN_ON_ONCE(!mutex_is_locked(&group->mark_mutex));
	if (group->flags & FSNOTIFY_GROUP_NOFS)
		WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
}


enum fsnotify_data_type {
	FSNOTIFY_EVENT_NONE,
	FSNOTIFY_EVENT_PATH,
	FSNOTIFY_EVENT_INODE,
	FSNOTIFY_EVENT_DENTRY,
	FSNOTIFY_EVENT_ERROR,
};

struct fs_error_report {
	int error;
	struct inode *inode;
	struct super_block *sb;
};

static inline struct inode *fsnotify_data_inode(const void *data, int data_type)
{
	switch (data_type) {
	case FSNOTIFY_EVENT_INODE:
		return (struct inode *)data;
	case FSNOTIFY_EVENT_DENTRY:
		return d_inode(data);
	case FSNOTIFY_EVENT_PATH:
		return d_inode(((const struct path *)data)->dentry);
	case FSNOTIFY_EVENT_ERROR:
		return ((struct fs_error_report *)data)->inode;
	default:
		return NULL;
	}
}

static inline struct dentry *fsnotify_data_dentry(const void *data, int data_type)
{
	switch (data_type) {
	case FSNOTIFY_EVENT_DENTRY:
		
		return (struct dentry *)data;
	case FSNOTIFY_EVENT_PATH:
		return ((const struct path *)data)->dentry;
	default:
		return NULL;
	}
}

static inline const struct path *fsnotify_data_path(const void *data,
						    int data_type)
{
	switch (data_type) {
	case FSNOTIFY_EVENT_PATH:
		return data;
	default:
		return NULL;
	}
}

static inline struct super_block *fsnotify_data_sb(const void *data,
						   int data_type)
{
	switch (data_type) {
	case FSNOTIFY_EVENT_INODE:
		return ((struct inode *)data)->i_sb;
	case FSNOTIFY_EVENT_DENTRY:
		return ((struct dentry *)data)->d_sb;
	case FSNOTIFY_EVENT_PATH:
		return ((const struct path *)data)->dentry->d_sb;
	case FSNOTIFY_EVENT_ERROR:
		return ((struct fs_error_report *) data)->sb;
	default:
		return NULL;
	}
}

static inline struct fs_error_report *fsnotify_data_error_report(
							const void *data,
							int data_type)
{
	switch (data_type) {
	case FSNOTIFY_EVENT_ERROR:
		return (struct fs_error_report *) data;
	default:
		return NULL;
	}
}


enum fsnotify_iter_type {
	FSNOTIFY_ITER_TYPE_INODE,
	FSNOTIFY_ITER_TYPE_VFSMOUNT,
	FSNOTIFY_ITER_TYPE_SB,
	FSNOTIFY_ITER_TYPE_PARENT,
	FSNOTIFY_ITER_TYPE_INODE2,
	FSNOTIFY_ITER_TYPE_COUNT
};


enum fsnotify_obj_type {
	FSNOTIFY_OBJ_TYPE_ANY = -1,
	FSNOTIFY_OBJ_TYPE_INODE,
	FSNOTIFY_OBJ_TYPE_VFSMOUNT,
	FSNOTIFY_OBJ_TYPE_SB,
	FSNOTIFY_OBJ_TYPE_COUNT,
	FSNOTIFY_OBJ_TYPE_DETACHED = FSNOTIFY_OBJ_TYPE_COUNT
};

static inline bool fsnotify_valid_obj_type(unsigned int obj_type)
{
	return (obj_type < FSNOTIFY_OBJ_TYPE_COUNT);
}

struct fsnotify_iter_info {
	struct fsnotify_mark *marks[FSNOTIFY_ITER_TYPE_COUNT];
	struct fsnotify_group *current_group;
	unsigned int report_mask;
	int srcu_idx;
};

static inline bool fsnotify_iter_should_report_type(
		struct fsnotify_iter_info *iter_info, int iter_type)
{
	return (iter_info->report_mask & (1U << iter_type));
}

static inline void fsnotify_iter_set_report_type(
		struct fsnotify_iter_info *iter_info, int iter_type)
{
	iter_info->report_mask |= (1U << iter_type);
}

static inline struct fsnotify_mark *fsnotify_iter_mark(
		struct fsnotify_iter_info *iter_info, int iter_type)
{
	if (fsnotify_iter_should_report_type(iter_info, iter_type))
		return iter_info->marks[iter_type];
	return NULL;
}

static inline int fsnotify_iter_step(struct fsnotify_iter_info *iter, int type,
				     struct fsnotify_mark **markp)
{
	while (type < FSNOTIFY_ITER_TYPE_COUNT) {
		*markp = fsnotify_iter_mark(iter, type);
		if (*markp)
			break;
		type++;
	}
	return type;
}

#define FSNOTIFY_ITER_FUNCS(name, NAME) \
static inline struct fsnotify_mark *fsnotify_iter_##name##_mark( \
		struct fsnotify_iter_info *iter_info) \
{ \
	return fsnotify_iter_mark(iter_info, FSNOTIFY_ITER_TYPE_##NAME); \
}

FSNOTIFY_ITER_FUNCS(inode, INODE)
FSNOTIFY_ITER_FUNCS(parent, PARENT)
FSNOTIFY_ITER_FUNCS(vfsmount, VFSMOUNT)
FSNOTIFY_ITER_FUNCS(sb, SB)

#define fsnotify_foreach_iter_type(type) \
	for (type = 0; type < FSNOTIFY_ITER_TYPE_COUNT; type++)
#define fsnotify_foreach_iter_mark_type(iter, mark, type) \
	for (type = 0; \
	     type = fsnotify_iter_step(iter, type, &mark), \
	     type < FSNOTIFY_ITER_TYPE_COUNT; \
	     type++)


struct fsnotify_mark_connector;
typedef struct fsnotify_mark_connector __rcu *fsnotify_connp_t;


struct fsnotify_mark_connector {
	spinlock_t lock;
	unsigned short type;	
#define FSNOTIFY_CONN_FLAG_HAS_FSID	0x01
#define FSNOTIFY_CONN_FLAG_HAS_IREF	0x02
	unsigned short flags;	
	__kernel_fsid_t fsid;	
	union {
		
		fsnotify_connp_t *obj;
		
		struct fsnotify_mark_connector *destroy_next;
	};
	struct hlist_head list;
};


struct fsnotify_mark {
	
	__u32 mask;
	
	refcount_t refcnt;
	
	struct fsnotify_group *group;
	
	struct list_head g_list;
	
	spinlock_t lock;
	
	struct hlist_node obj_list;
	
	struct fsnotify_mark_connector *connector;
	
	__u32 ignore_mask;
	
#define FSNOTIFY_MARK_FLAG_ALIVE		0x0001
#define FSNOTIFY_MARK_FLAG_ATTACHED		0x0002
	
#define FSNOTIFY_MARK_FLAG_EXCL_UNLINK		0x0010
#define FSNOTIFY_MARK_FLAG_IN_ONESHOT		0x0020
	
#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY	0x0100
#define FSNOTIFY_MARK_FLAG_NO_IREF		0x0200
#define FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS	0x0400
	unsigned int flags;		
};

#ifdef CONFIG_FSNOTIFY




extern int fsnotify(__u32 mask, const void *data, int data_type,
		    struct inode *dir, const struct qstr *name,
		    struct inode *inode, u32 cookie);
extern int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
			   int data_type);
extern void __fsnotify_inode_delete(struct inode *inode);
extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
extern void fsnotify_sb_delete(struct super_block *sb);
extern u32 fsnotify_get_cookie(void);

static inline __u32 fsnotify_parent_needed_mask(__u32 mask)
{
	
	if (!(mask & FS_EVENT_ON_CHILD))
		return 0;
	
	return mask & FS_EVENTS_POSS_TO_PARENT;
}

static inline int fsnotify_inode_watches_children(struct inode *inode)
{
	__u32 parent_mask = READ_ONCE(inode->i_fsnotify_mask);

	
	if (!(parent_mask & FS_EVENT_ON_CHILD))
		return 0;
	
	return parent_mask & FS_EVENTS_POSS_ON_CHILD;
}


static inline void fsnotify_update_flags(struct dentry *dentry)
{
	assert_spin_locked(&dentry->d_lock);

	
	if (fsnotify_inode_watches_children(dentry->d_parent->d_inode))
		dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
	else
		dentry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
}




extern struct fsnotify_group *fsnotify_alloc_group(
				const struct fsnotify_ops *ops,
				int flags);

extern void fsnotify_get_group(struct fsnotify_group *group);

extern void fsnotify_put_group(struct fsnotify_group *group);

extern void fsnotify_group_stop_queueing(struct fsnotify_group *group);

extern void fsnotify_destroy_group(struct fsnotify_group *group);

extern int fsnotify_fasync(int fd, struct file *file, int on);

extern void fsnotify_destroy_event(struct fsnotify_group *group,
				   struct fsnotify_event *event);

extern int fsnotify_insert_event(struct fsnotify_group *group,
				 struct fsnotify_event *event,
				 int (*merge)(struct fsnotify_group *,
					      struct fsnotify_event *),
				 void (*insert)(struct fsnotify_group *,
						struct fsnotify_event *));

static inline int fsnotify_add_event(struct fsnotify_group *group,
				     struct fsnotify_event *event,
				     int (*merge)(struct fsnotify_group *,
						  struct fsnotify_event *))
{
	return fsnotify_insert_event(group, event, merge, NULL);
}


static inline void fsnotify_queue_overflow(struct fsnotify_group *group)
{
	fsnotify_add_event(group, group->overflow_event, NULL);
}

static inline bool fsnotify_is_overflow_event(u32 mask)
{
	return mask & FS_Q_OVERFLOW;
}

static inline bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group)
{
	assert_spin_locked(&group->notification_lock);

	return list_empty(&group->notification_list);
}

extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group);

extern struct fsnotify_event *fsnotify_peek_first_event(struct fsnotify_group *group);

extern struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group *group);

extern void fsnotify_remove_queued_event(struct fsnotify_group *group,
					 struct fsnotify_event *event);




static inline __u32 fsnotify_ignore_mask(struct fsnotify_mark *mark)
{
	__u32 ignore_mask = mark->ignore_mask;

	
	if (mark->flags & FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS)
		return ignore_mask;

	
	ignore_mask |= FS_ISDIR;
	ignore_mask &= ~FS_EVENT_ON_CHILD;
	ignore_mask |= mark->mask & FS_EVENT_ON_CHILD;

	return ignore_mask;
}


static inline __u32 fsnotify_ignored_events(struct fsnotify_mark *mark)
{
	return mark->ignore_mask & ALL_FSNOTIFY_EVENTS;
}


static inline bool fsnotify_mask_applicable(__u32 mask, bool is_dir,
					    int iter_type)
{
	
	if (is_dir && !(mask & FS_ISDIR))
		return false;

	
	if (iter_type == FSNOTIFY_ITER_TYPE_PARENT &&
	    !(mask & FS_EVENT_ON_CHILD))
		return false;

	return true;
}


static inline __u32 fsnotify_effective_ignore_mask(struct fsnotify_mark *mark,
						   bool is_dir, int iter_type)
{
	__u32 ignore_mask = fsnotify_ignored_events(mark);

	if (!ignore_mask)
		return 0;

	
	if (!is_dir && iter_type != FSNOTIFY_ITER_TYPE_PARENT)
		return ignore_mask;

	ignore_mask = fsnotify_ignore_mask(mark);
	if (!fsnotify_mask_applicable(ignore_mask, is_dir, iter_type))
		return 0;

	return ignore_mask & ALL_FSNOTIFY_EVENTS;
}


static inline __u32 fsnotify_calc_mask(struct fsnotify_mark *mark)
{
	__u32 mask = mark->mask;

	if (!fsnotify_ignored_events(mark))
		return mask;

	
	if (!(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
		mask |= FS_MODIFY;

	
	return mask | mark->ignore_mask;
}


extern __u32 fsnotify_conn_mask(struct fsnotify_mark_connector *conn);

extern void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn);
extern void fsnotify_init_mark(struct fsnotify_mark *mark,
			       struct fsnotify_group *group);

extern struct fsnotify_mark *fsnotify_find_mark(fsnotify_connp_t *connp,
						struct fsnotify_group *group);

extern int fsnotify_get_conn_fsid(const struct fsnotify_mark_connector *conn,
				  __kernel_fsid_t *fsid);

extern int fsnotify_add_mark(struct fsnotify_mark *mark,
			     fsnotify_connp_t *connp, unsigned int obj_type,
			     int add_flags, __kernel_fsid_t *fsid);
extern int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
				    fsnotify_connp_t *connp,
				    unsigned int obj_type, int add_flags,
				    __kernel_fsid_t *fsid);


static inline int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
					  struct inode *inode,
					  int add_flags)
{
	return fsnotify_add_mark(mark, &inode->i_fsnotify_marks,
				 FSNOTIFY_OBJ_TYPE_INODE, add_flags, NULL);
}
static inline int fsnotify_add_inode_mark_locked(struct fsnotify_mark *mark,
						 struct inode *inode,
						 int add_flags)
{
	return fsnotify_add_mark_locked(mark, &inode->i_fsnotify_marks,
					FSNOTIFY_OBJ_TYPE_INODE, add_flags,
					NULL);
}


extern void fsnotify_destroy_mark(struct fsnotify_mark *mark,
				  struct fsnotify_group *group);

extern void fsnotify_detach_mark(struct fsnotify_mark *mark);

extern void fsnotify_free_mark(struct fsnotify_mark *mark);

extern void fsnotify_wait_marks_destroyed(void);

extern void fsnotify_clear_marks_by_group(struct fsnotify_group *group,
					  unsigned int obj_type);

static inline void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
{
	fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_VFSMOUNT);
}

static inline void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group)
{
	fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_INODE);
}

static inline void fsnotify_clear_sb_marks_by_group(struct fsnotify_group *group)
{
	fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_SB);
}
extern void fsnotify_get_mark(struct fsnotify_mark *mark);
extern void fsnotify_put_mark(struct fsnotify_mark *mark);
struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark);
extern void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info);
extern bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info);

static inline void fsnotify_init_event(struct fsnotify_event *event)
{
	INIT_LIST_HEAD(&event->list);
}

#else

static inline int fsnotify(__u32 mask, const void *data, int data_type,
			   struct inode *dir, const struct qstr *name,
			   struct inode *inode, u32 cookie)
{
	return 0;
}

static inline int __fsnotify_parent(struct dentry *dentry, __u32 mask,
				  const void *data, int data_type)
{
	return 0;
}

static inline void __fsnotify_inode_delete(struct inode *inode)
{}

static inline void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
{}

static inline void fsnotify_sb_delete(struct super_block *sb)
{}

static inline void fsnotify_update_flags(struct dentry *dentry)
{}

static inline u32 fsnotify_get_cookie(void)
{
	return 0;
}

static inline void fsnotify_unmount_inodes(struct super_block *sb)
{}

#endif	

#endif	

#endif	
