/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_NS_COMMON_H
#define _LINUX_NS_COMMON_H

#include <linux/refcount.h>
#include <linux/rbtree.h>

struct proc_ns_operations;

struct cgroup_namespace;
struct ipc_namespace;
struct mnt_namespace;
struct net;
struct pid_namespace;
struct time_namespace;
struct user_namespace;
struct uts_namespace;

extern struct cgroup_namespace init_cgroup_ns;
extern struct ipc_namespace init_ipc_ns;
extern struct mnt_namespace init_mnt_ns;
extern struct net init_net;
extern struct pid_namespace init_pid_ns;
extern struct time_namespace init_time_ns;
extern struct user_namespace init_user_ns;
extern struct uts_namespace init_uts_ns;

struct ns_common {
	struct dentry *stashed;
	const struct proc_ns_operations *ops;
	unsigned int inum;
	refcount_t count;
	union {
		struct {
			u64 ns_id;
			struct rb_node ns_tree_node;
			struct list_head ns_list_node;
		};
		struct rcu_head ns_rcu;
	};
};

int __ns_common_init(struct ns_common *ns, const struct proc_ns_operations *ops, int inum);

#define to_ns_common(__ns)                              \
	_Generic((__ns),                                \
		struct cgroup_namespace *: &(__ns)->ns, \
		struct ipc_namespace *:    &(__ns)->ns, \
		struct mnt_namespace *:    &(__ns)->ns, \
		struct net *:              &(__ns)->ns, \
		struct pid_namespace *:    &(__ns)->ns, \
		struct time_namespace *:   &(__ns)->ns, \
		struct user_namespace *:   &(__ns)->ns, \
		struct uts_namespace *:    &(__ns)->ns)

#define ns_init_inum(__ns)                                     \
	_Generic((__ns),                                       \
		struct cgroup_namespace *: CGROUP_NS_INIT_INO, \
		struct ipc_namespace *:    IPC_NS_INIT_INO,    \
		struct mnt_namespace *:    MNT_NS_INIT_INO,    \
		struct net *:              NET_NS_INIT_INO,    \
		struct pid_namespace *:    PID_NS_INIT_INO,    \
		struct time_namespace *:   TIME_NS_INIT_INO,   \
		struct user_namespace *:   USER_NS_INIT_INO,   \
		struct uts_namespace *:    UTS_NS_INIT_INO)

#define ns_init_ns(__ns)                                    \
	_Generic((__ns),                                    \
		struct cgroup_namespace *: &init_cgroup_ns, \
		struct ipc_namespace *:    &init_ipc_ns,    \
		struct mnt_namespace *:    &init_mnt_ns,     \
		struct net *:              &init_net,       \
		struct pid_namespace *:    &init_pid_ns,    \
		struct time_namespace *:   &init_time_ns,   \
		struct user_namespace *:   &init_user_ns,   \
		struct uts_namespace *:    &init_uts_ns)

#define ns_common_init(__ns, __ops) \
	__ns_common_init(to_ns_common(__ns), __ops, (((__ns) == ns_init_ns(__ns)) ? ns_init_inum(__ns) : 0))

#define ns_common_init_inum(__ns, __ops, __inum) __ns_common_init(to_ns_common(__ns), __ops, __inum)

#endif