include/linux/proc_ns.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * procfs namespace bits
 */
#ifndef _LINUX_PROC_NS_H
#define _LINUX_PROC_NS_H

#include <linux/ns_common.h>

struct pid_namespace;
struct nsset;
struct path;
struct task_struct;
struct inode;

struct proc_ns_operations {
	const char *name;
	const char *real_ns_name;
	int type;
	struct ns_common *(*get)(struct task_struct *task);
	void (*put)(struct ns_common *ns);
	int (*install)(struct nsset *nsset, struct ns_common *ns);
	struct user_namespace *(*owner)(struct ns_common *ns);
	struct ns_common *(*get_parent)(struct ns_common *ns);
} __randomize_layout;

extern const struct proc_ns_operations netns_operations;
extern const struct proc_ns_operations utsns_operations;
extern const struct proc_ns_operations ipcns_operations;
extern const struct proc_ns_operations pidns_operations;
extern const struct proc_ns_operations pidns_for_children_operations;
extern const struct proc_ns_operations userns_operations;
extern const struct proc_ns_operations mntns_operations;
extern const struct proc_ns_operations cgroupns_operations;
extern const struct proc_ns_operations timens_operations;
extern const struct proc_ns_operations timens_for_children_operations;

/*
 * We always define these enumerators
 */
enum {
	PROC_ROOT_INO		= 1,
	PROC_IPC_INIT_INO	= 0xEFFFFFFFU,
	PROC_UTS_INIT_INO	= 0xEFFFFFFEU,
	PROC_USER_INIT_INO	= 0xEFFFFFFDU,
	PROC_PID_INIT_INO	= 0xEFFFFFFCU,
	PROC_CGROUP_INIT_INO	= 0xEFFFFFFBU,
	PROC_TIME_INIT_INO	= 0xEFFFFFFAU,
};

#ifdef CONFIG_PROC_FS

extern int proc_alloc_inum(unsigned int *pino);
extern void proc_free_inum(unsigned int inum);

#else /* CONFIG_PROC_FS */

static inline int proc_alloc_inum(unsigned int *inum)
{
	*inum = 1;
	return 0;
}
static inline void proc_free_inum(unsigned int inum) {}

#endif /* CONFIG_PROC_FS */

/**
 * init_ns_common - Initialise the common part of a namespace
 * @ns: The namespace to initialise
 * @anon: The namespace will be anonymous
 *
 * Set up the common part of a namespace, assigning an inode number and
 * creating a tag.  Returns 0 on success and a negative error code on failure.
 * On failure, the caller must call destroy_ns_common().
 */
static inline int init_ns_common(struct ns_common *ns, bool anon)
{
	struct ns_tag *tag;

	tag = kzalloc(sizeof(*tag), GFP_KERNEL);
	if (!tag)
		return -ENOMEM;

	refcount_set(&tag->usage, 1);
	ns->tag = tag;
	ns->inum = 0;
	atomic_long_set(&ns->stashed, 0);
	refcount_set(&ns->count, 1);

	return anon ? 0 : proc_alloc_inum(&ns->inum);
}

/**
 * destroy_ns_common - Clean up the common part of a namespace
 * @ns: The namespace to clean up
 */
static inline void destroy_ns_common(struct ns_common *ns)
{
	put_ns_tag(ns->tag);
	ns->tag = NULL;
	if (ns->inum) {
		proc_free_inum(ns->inum);
		ns->inum = 0;
	}
}

extern struct file *proc_ns_fget(int fd);
#define get_proc_ns(inode) ((struct ns_common *)(inode)->i_private)
extern int ns_get_path(struct path *path, struct task_struct *task,
			const struct proc_ns_operations *ns_ops);
typedef struct ns_common *ns_get_path_helper_t(void *);
extern int ns_get_path_cb(struct path *path, ns_get_path_helper_t ns_get_cb,
			    void *private_data);

extern bool ns_match(const struct ns_common *ns, dev_t dev, ino_t ino);

extern int ns_get_name(char *buf, size_t size, struct task_struct *task,
			const struct proc_ns_operations *ns_ops);
extern void nsfs_init(void);

#endif /* _LINUX_PROC_NS_H */