237 lines
7.2 KiB
C
237 lines
7.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* sysctl.h: General linux system control interface
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*
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* Begun 24 March 1995, Stephen Tweedie
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*
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****************************************************************
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****************************************************************
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**
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** WARNING:
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** The values in this file are exported to user space via
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** the sysctl() binary interface. Do *NOT* change the
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** numbering of any existing values here, and do not change
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** any numbers within any one set of values. If you have to
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** redefine an existing interface, use a new number for it.
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** The kernel will then return -ENOTDIR to any application using
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** the old binary interface.
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**
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****************************************************************
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****************************************************************
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*/
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#ifndef _LINUX_SYSCTL_H
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#define _LINUX_SYSCTL_H
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#include <linux/list.h>
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#include <linux/rcupdate.h>
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#include <linux/wait.h>
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#include <linux/rbtree.h>
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#include <linux/uidgid.h>
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#include <uapi/linux/sysctl.h>
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/* For the /proc/sys support */
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struct completion;
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struct ctl_table;
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struct nsproxy;
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struct ctl_table_root;
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struct ctl_table_header;
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struct ctl_dir;
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typedef int proc_handler (struct ctl_table *ctl, int write,
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void __user *buffer, size_t *lenp, loff_t *ppos);
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extern int proc_dostring(struct ctl_table *, int,
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void __user *, size_t *, loff_t *);
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extern int proc_dointvec(struct ctl_table *, int,
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void __user *, size_t *, loff_t *);
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extern int proc_douintvec(struct ctl_table *, int,
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void __user *, size_t *, loff_t *);
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extern int proc_dointvec_minmax(struct ctl_table *, int,
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void __user *, size_t *, loff_t *);
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extern int proc_douintvec_minmax(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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extern int proc_dointvec_jiffies(struct ctl_table *, int,
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void __user *, size_t *, loff_t *);
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extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int,
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void __user *, size_t *, loff_t *);
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extern int proc_dointvec_ms_jiffies(struct ctl_table *, int,
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void __user *, size_t *, loff_t *);
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extern int proc_doulongvec_minmax(struct ctl_table *, int,
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void __user *, size_t *, loff_t *);
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extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int,
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void __user *, size_t *, loff_t *);
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extern int proc_do_large_bitmap(struct ctl_table *, int,
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void __user *, size_t *, loff_t *);
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/*
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* Register a set of sysctl names by calling register_sysctl_table
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* with an initialised array of struct ctl_table's. An entry with
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* NULL procname terminates the table. table->de will be
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* set up by the registration and need not be initialised in advance.
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*
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* sysctl names can be mirrored automatically under /proc/sys. The
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* procname supplied controls /proc naming.
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*
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* The table's mode will be honoured both for sys_sysctl(2) and
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* proc-fs access.
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*
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* Leaf nodes in the sysctl tree will be represented by a single file
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* under /proc; non-leaf nodes will be represented by directories. A
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* null procname disables /proc mirroring at this node.
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*
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* sysctl(2) can automatically manage read and write requests through
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* the sysctl table. The data and maxlen fields of the ctl_table
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* struct enable minimal validation of the values being written to be
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* performed, and the mode field allows minimal authentication.
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*
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* There must be a proc_handler routine for any terminal nodes
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* mirrored under /proc/sys (non-terminals are handled by a built-in
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* directory handler). Several default handlers are available to
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* cover common cases.
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*/
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/* Support for userspace poll() to watch for changes */
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struct ctl_table_poll {
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atomic_t event;
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wait_queue_head_t wait;
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};
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static inline void *proc_sys_poll_event(struct ctl_table_poll *poll)
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{
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return (void *)(unsigned long)atomic_read(&poll->event);
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}
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#define __CTL_TABLE_POLL_INITIALIZER(name) { \
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.event = ATOMIC_INIT(0), \
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.wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) }
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#define DEFINE_CTL_TABLE_POLL(name) \
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struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name)
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/* A sysctl table is an array of struct ctl_table: */
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struct ctl_table
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{
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const char *procname; /* Text ID for /proc/sys, or zero */
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void *data;
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int maxlen;
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umode_t mode;
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struct ctl_table *child; /* Deprecated */
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proc_handler *proc_handler; /* Callback for text formatting */
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struct ctl_table_poll *poll;
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void *extra1;
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void *extra2;
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} __randomize_layout;
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struct ctl_node {
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struct rb_node node;
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struct ctl_table_header *header;
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};
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/* struct ctl_table_header is used to maintain dynamic lists of
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struct ctl_table trees. */
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struct ctl_table_header
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{
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union {
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struct {
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struct ctl_table *ctl_table;
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int used;
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int count;
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int nreg;
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};
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struct rcu_head rcu;
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};
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struct completion *unregistering;
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struct ctl_table *ctl_table_arg;
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struct ctl_table_root *root;
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struct ctl_table_set *set;
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struct ctl_dir *parent;
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struct ctl_node *node;
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struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */
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};
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struct ctl_dir {
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/* Header must be at the start of ctl_dir */
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struct ctl_table_header header;
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struct rb_root root;
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};
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struct ctl_table_set {
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int (*is_seen)(struct ctl_table_set *);
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struct ctl_dir dir;
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};
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struct ctl_table_root {
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struct ctl_table_set default_set;
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struct ctl_table_set *(*lookup)(struct ctl_table_root *root);
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void (*set_ownership)(struct ctl_table_header *head,
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struct ctl_table *table,
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kuid_t *uid, kgid_t *gid);
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int (*permissions)(struct ctl_table_header *head, struct ctl_table *table);
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};
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/* struct ctl_path describes where in the hierarchy a table is added */
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struct ctl_path {
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const char *procname;
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};
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#ifdef CONFIG_SYSCTL
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void proc_sys_poll_notify(struct ctl_table_poll *poll);
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extern void setup_sysctl_set(struct ctl_table_set *p,
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struct ctl_table_root *root,
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int (*is_seen)(struct ctl_table_set *));
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extern void retire_sysctl_set(struct ctl_table_set *set);
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struct ctl_table_header *__register_sysctl_table(
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struct ctl_table_set *set,
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const char *path, struct ctl_table *table);
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struct ctl_table_header *__register_sysctl_paths(
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struct ctl_table_set *set,
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const struct ctl_path *path, struct ctl_table *table);
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struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table);
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struct ctl_table_header *register_sysctl_table(struct ctl_table * table);
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struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
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struct ctl_table *table);
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void unregister_sysctl_table(struct ctl_table_header * table);
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extern int sysctl_init(void);
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extern struct ctl_table sysctl_mount_point[];
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#else /* CONFIG_SYSCTL */
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static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
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{
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return NULL;
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}
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static inline struct ctl_table_header *register_sysctl_paths(
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const struct ctl_path *path, struct ctl_table *table)
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{
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return NULL;
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}
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static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table)
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{
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return NULL;
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}
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static inline void unregister_sysctl_table(struct ctl_table_header * table)
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{
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}
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static inline void setup_sysctl_set(struct ctl_table_set *p,
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struct ctl_table_root *root,
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int (*is_seen)(struct ctl_table_set *))
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{
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}
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#endif /* CONFIG_SYSCTL */
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int sysctl_max_threads(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp, loff_t *ppos);
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#endif /* _LINUX_SYSCTL_H */
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