/*
* sysctl.h: General linux system control interface
*
* Begun 24 March 1995, Stephen Tweedie
*
****************************************************************
****************************************************************
**
** WARNING:
** The values in this file are exported to user space via
** the sysctl() binary interface. Do *NOT* change the
** numbering of any existing values here, and do not change
** any numbers within any one set of values. If you have to
** redefine an existing interface, use a new number for it.
** The kernel will then return -ENOTDIR to any application using
** the old binary interface.
**
****************************************************************
****************************************************************
*/
#ifndef _LINUX_SYSCTL_H
#define _LINUX_SYSCTL_H

#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/wait.h>
#include <linux/rbtree.h>
#include <uapi/linux/sysctl.h>

/* For the /proc/sys support */
struct ctl_table;
struct nsproxy;
struct ctl_table_root;
struct ctl_table_header;
struct ctl_dir;

typedef struct ctl_table ctl_table;

typedef int proc_handler (struct ctl_table *ctl, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);

extern int proc_dostring(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_dointvec(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_dointvec_minmax(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_dointvec_jiffies(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_dointvec_ms_jiffies(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_doulongvec_minmax(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int,
void __user *, size_t *, loff_t *);
extern int proc_do_large_bitmap(struct ctl_table *, int,
void __user *, size_t *, loff_t *);

/*
* Register a set of sysctl names by calling register_sysctl_table
* with an initialised array of struct ctl_table's. An entry with
* NULL procname terminates the table. table->de will be
* set up by the registration and need not be initialised in advance.
*
* sysctl names can be mirrored automatically under /proc/sys. The
* procname supplied controls /proc naming.
*
* The table's mode will be honoured both for sys_sysctl(2) and
* proc-fs access.
*
* Leaf nodes in the sysctl tree will be represented by a single file
* under /proc; non-leaf nodes will be represented by directories. A
* null procname disables /proc mirroring at this node.
*
* sysctl(2) can automatically manage read and write requests through
* the sysctl table. The data and maxlen fields of the ctl_table
* struct enable minimal validation of the values being written to be
* performed, and the mode field allows minimal authentication.
*
* There must be a proc_handler routine for any terminal nodes
* mirrored under /proc/sys (non-terminals are handled by a built-in
* directory handler). Several default handlers are available to
* cover common cases.
*/

/* Support for userspace poll() to watch for changes */
struct ctl_table_poll {
atomic_t event;
wait_queue_head_t wait;
};

static inline void *proc_sys_poll_event(struct ctl_table_poll *poll)
{
return (void *)(unsigned long)atomic_read(&poll->event);
}

#define __CTL_TABLE_POLL_INITIALIZER(name) { \
.event = ATOMIC_INIT(0), \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) }

#define DEFINE_CTL_TABLE_POLL(name) \
struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name)

/* A sysctl table is an array of struct ctl_table: */
struct ctl_table
{
const char *procname; /* Text ID for /proc/sys, or zero */
void *data;
int maxlen;
umode_t mode;
struct ctl_table *child; /* Deprecated */
proc_handler *proc_handler; /* Callback for text formatting */
struct ctl_table_poll *poll;
void *extra1;
void *extra2;
};

struct ctl_node {
struct rb_node node;
struct ctl_table_header *header;
};

/* struct ctl_table_header is used to maintain dynamic lists of
struct ctl_table trees. */
struct ctl_table_header
{
union {
struct {
struct ctl_table *ctl_table;
int used;
int count;
int nreg;
};
struct rcu_head rcu;
};
struct completion *unregistering;
struct ctl_table *ctl_table_arg;
struct ctl_table_root *root;
struct ctl_table_set *set;
struct ctl_dir *parent;
struct ctl_node *node;
};

struct ctl_dir {
/* Header must be at the start of ctl_dir */
struct ctl_table_header header;
struct rb_root root;
};

struct ctl_table_set {
int (*is_seen)(struct ctl_table_set *);
struct ctl_dir dir;
};

struct ctl_table_root {
struct ctl_table_set default_set;
struct ctl_table_set *(*lookup)(struct ctl_table_root *root,
struct nsproxy *namespaces);
int (*permissions)(struct ctl_table_header *head, struct ctl_table *table);
};

/* struct ctl_path describes where in the hierarchy a table is added */
struct ctl_path {
const char *procname;
};

#ifdef CONFIG_SYSCTL

void proc_sys_poll_notify(struct ctl_table_poll *poll);

extern void setup_sysctl_set(struct ctl_table_set *p,
struct ctl_table_root *root,
int (*is_seen)(struct ctl_table_set *));
extern void retire_sysctl_set(struct ctl_table_set *set);

void register_sysctl_root(struct ctl_table_root *root);
struct ctl_table_header *__register_sysctl_table(
struct ctl_table_set *set,
const char *path, struct ctl_table *table);
struct ctl_table_header *__register_sysctl_paths(
struct ctl_table_set *set,
const struct ctl_path *path, struct ctl_table *table);
struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table);
struct ctl_table_header *register_sysctl_table(struct ctl_table * table);
struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
struct ctl_table *table);

void unregister_sysctl_table(struct ctl_table_header * table);

extern int sysctl_init(void);
#else /* CONFIG_SYSCTL */
static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
{
return NULL;
}

static inline struct ctl_table_header *register_sysctl_paths(
const struct ctl_path *path, struct ctl_table *table)
{
return NULL;
}

static inline void unregister_sysctl_table(struct ctl_table_header * table)
{
}

static inline void setup_sysctl_set(struct ctl_table_set *p,
struct ctl_table_root *root,
int (*is_seen)(struct ctl_table_set *))
{
}

#endif /* CONFIG_SYSCTL */

#endif /* _LINUX_SYSCTL_H */