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/* SPDX-License-Identifier: GPL-2.0 */
/*
* 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 <linux/uidgid.h>
#include <uapi/linux/sysctl.h>
/* For the /proc/sys support */
struct completion;
struct ctl_table;
struct nsproxy;
struct ctl_table_root;
struct ctl_table_header;
struct ctl_dir;
/* Keep the same order as in fs/proc/proc_sysctl.c */
#define SYSCTL_ZERO ((void *)&sysctl_vals[0])
#define SYSCTL_ONE ((void *)&sysctl_vals[1])
#define SYSCTL_TWO ((void *)&sysctl_vals[2])
#define SYSCTL_THREE ((void *)&sysctl_vals[3])
#define SYSCTL_FOUR ((void *)&sysctl_vals[4])
#define SYSCTL_ONE_HUNDRED ((void *)&sysctl_vals[5])
#define SYSCTL_TWO_HUNDRED ((void *)&sysctl_vals[6])
#define SYSCTL_ONE_THOUSAND ((void *)&sysctl_vals[7])
#define SYSCTL_THREE_THOUSAND ((void *)&sysctl_vals[8])
#define SYSCTL_INT_MAX ((void *)&sysctl_vals[9])
/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
#define SYSCTL_MAXOLDUID ((void *)&sysctl_vals[10])
#define SYSCTL_NEG_ONE ((void *)&sysctl_vals[11])
extern const int sysctl_vals[];
#define SYSCTL_LONG_ZERO ((void *)&sysctl_long_vals[0])
#define SYSCTL_LONG_ONE ((void *)&sysctl_long_vals[1])
#define SYSCTL_LONG_MAX ((void *)&sysctl_long_vals[2])
extern const unsigned long sysctl_long_vals[];
typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer,
size_t *lenp, loff_t *ppos);
int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_dobool(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos);
int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos);
int proc_dou8vec_minmax(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos);
int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos);
int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *,
loff_t *);
int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *,
loff_t *);
int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *,
size_t *, loff_t *);
int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_do_static_key(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos);
/*
* Register a set of sysctl names by calling register_sysctl
* 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 for 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.
*
* 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;
/**
* enum type - Enumeration to differentiate between ctl target types
* @SYSCTL_TABLE_TYPE_DEFAULT: ctl target with no special considerations
* @SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY: Used to identify a permanently
* empty directory target to serve
* as mount point.
*/
enum {
SYSCTL_TABLE_TYPE_DEFAULT,
SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY
} type;
proc_handler *proc_handler; /* Callback for text formatting */
struct ctl_table_poll *poll;
void *extra1;
void *extra2;
} __randomize_layout;
struct ctl_node {
struct rb_node node;
struct ctl_table_header *header;
};
/**
* struct ctl_table_header - maintains dynamic lists of struct ctl_table trees
* @ctl_table: pointer to the first element in ctl_table array
* @ctl_table_size: number of elements pointed by @ctl_table
* @used: The entry will never be touched when equal to 0.
* @count: Upped every time something is added to @inodes and downed every time
* something is removed from inodes
* @nreg: When nreg drops to 0 the ctl_table_header will be unregistered.
* @rcu: Delays the freeing of the inode. Introduced with "unfuck proc_sysctl ->d_compare()"
*
*/
struct ctl_table_header {
union {
struct {
struct ctl_table *ctl_table;
int ctl_table_size;
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 hlist_head inodes; /* head for proc_inode->sysctl_inodes */
};
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);
void (*set_ownership)(struct ctl_table_header *head,
kuid_t *uid, kgid_t *gid);
int (*permissions)(struct ctl_table_header *head, struct ctl_table *table);
};
#define register_sysctl(path, table) \
register_sysctl_sz(path, table, ARRAY_SIZE(table))
#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);
struct ctl_table_header *__register_sysctl_table(
struct ctl_table_set *set,
const char *path, struct ctl_table *table, size_t table_size);
struct ctl_table_header *register_sysctl_sz(const char *path, struct ctl_table *table,
size_t table_size);
void unregister_sysctl_table(struct ctl_table_header * table);
extern int sysctl_init_bases(void);
extern void __register_sysctl_init(const char *path, struct ctl_table *table,
const char *table_name, size_t table_size);
#define register_sysctl_init(path, table) \
__register_sysctl_init(path, table, #table, ARRAY_SIZE(table))
extern struct ctl_table_header *register_sysctl_mount_point(const char *path);
void do_sysctl_args(void);
bool sysctl_is_alias(char *param);
int do_proc_douintvec(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos,
int (*conv)(unsigned long *lvalp,
unsigned int *valp,
int write, void *data),
void *data);
extern int pwrsw_enabled;
extern int unaligned_enabled;
extern int unaligned_dump_stack;
extern int no_unaligned_warning;
#else /* CONFIG_SYSCTL */
static inline void register_sysctl_init(const char *path, struct ctl_table *table)
{
}
static inline struct ctl_table_header *register_sysctl_mount_point(const char *path)
{
return NULL;
}
static inline struct ctl_table_header *register_sysctl_sz(const char *path,
struct ctl_table *table,
size_t table_size)
{
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 *))
{
}
static inline void do_sysctl_args(void)
{
}
static inline bool sysctl_is_alias(char *param)
{
return false;
}
#endif /* CONFIG_SYSCTL */
int sysctl_max_threads(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos);
#endif /* _LINUX_SYSCTL_H */