1 /* SPDX-License-Identifier: GPL-2.0 */
3 * sysctl.h: General linux system control interface
5 * Begun 24 March 1995, Stephen Tweedie
7 ****************************************************************
8 ****************************************************************
11 ** The values in this file are exported to user space via
12 ** the sysctl() binary interface. Do *NOT* change the
13 ** numbering of any existing values here, and do not change
14 ** any numbers within any one set of values. If you have to
15 ** redefine an existing interface, use a new number for it.
16 ** The kernel will then return -ENOTDIR to any application using
17 ** the old binary interface.
19 ****************************************************************
20 ****************************************************************
22 #ifndef _LINUX_SYSCTL_H
23 #define _LINUX_SYSCTL_H
25 #include <linux/list.h>
26 #include <linux/rcupdate.h>
27 #include <linux/wait.h>
28 #include <linux/rbtree.h>
29 #include <linux/uidgid.h>
30 #include <uapi/linux/sysctl.h>
32 /* For the /proc/sys support */
36 struct ctl_table_root
;
37 struct ctl_table_header
;
40 typedef int proc_handler (struct ctl_table
*ctl
, int write
,
41 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
);
43 extern int proc_dostring(struct ctl_table
*, int,
44 void __user
*, size_t *, loff_t
*);
45 extern int proc_dointvec(struct ctl_table
*, int,
46 void __user
*, size_t *, loff_t
*);
47 extern int proc_douintvec(struct ctl_table
*, int,
48 void __user
*, size_t *, loff_t
*);
49 extern int proc_dointvec_minmax(struct ctl_table
*, int,
50 void __user
*, size_t *, loff_t
*);
51 extern int proc_douintvec_minmax(struct ctl_table
*table
, int write
,
52 void __user
*buffer
, size_t *lenp
,
54 extern int proc_dopipe_max_size(struct ctl_table
*table
, int write
,
55 void __user
*buffer
, size_t *lenp
,
57 extern int proc_dointvec_jiffies(struct ctl_table
*, int,
58 void __user
*, size_t *, loff_t
*);
59 extern int proc_dointvec_userhz_jiffies(struct ctl_table
*, int,
60 void __user
*, size_t *, loff_t
*);
61 extern int proc_dointvec_ms_jiffies(struct ctl_table
*, int,
62 void __user
*, size_t *, loff_t
*);
63 extern int proc_doulongvec_minmax(struct ctl_table
*, int,
64 void __user
*, size_t *, loff_t
*);
65 extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table
*table
, int,
66 void __user
*, size_t *, loff_t
*);
67 extern int proc_do_large_bitmap(struct ctl_table
*, int,
68 void __user
*, size_t *, loff_t
*);
71 * Register a set of sysctl names by calling register_sysctl_table
72 * with an initialised array of struct ctl_table's. An entry with
73 * NULL procname terminates the table. table->de will be
74 * set up by the registration and need not be initialised in advance.
76 * sysctl names can be mirrored automatically under /proc/sys. The
77 * procname supplied controls /proc naming.
79 * The table's mode will be honoured both for sys_sysctl(2) and
82 * Leaf nodes in the sysctl tree will be represented by a single file
83 * under /proc; non-leaf nodes will be represented by directories. A
84 * null procname disables /proc mirroring at this node.
86 * sysctl(2) can automatically manage read and write requests through
87 * the sysctl table. The data and maxlen fields of the ctl_table
88 * struct enable minimal validation of the values being written to be
89 * performed, and the mode field allows minimal authentication.
91 * There must be a proc_handler routine for any terminal nodes
92 * mirrored under /proc/sys (non-terminals are handled by a built-in
93 * directory handler). Several default handlers are available to
97 /* Support for userspace poll() to watch for changes */
98 struct ctl_table_poll
{
100 wait_queue_head_t wait
;
103 static inline void *proc_sys_poll_event(struct ctl_table_poll
*poll
)
105 return (void *)(unsigned long)atomic_read(&poll
->event
);
108 #define __CTL_TABLE_POLL_INITIALIZER(name) { \
109 .event = ATOMIC_INIT(0), \
110 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) }
112 #define DEFINE_CTL_TABLE_POLL(name) \
113 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name)
115 /* A sysctl table is an array of struct ctl_table: */
118 const char *procname
; /* Text ID for /proc/sys, or zero */
122 struct ctl_table
*child
; /* Deprecated */
123 proc_handler
*proc_handler
; /* Callback for text formatting */
124 struct ctl_table_poll
*poll
;
127 } __randomize_layout
;
131 struct ctl_table_header
*header
;
134 /* struct ctl_table_header is used to maintain dynamic lists of
135 struct ctl_table trees. */
136 struct ctl_table_header
140 struct ctl_table
*ctl_table
;
147 struct completion
*unregistering
;
148 struct ctl_table
*ctl_table_arg
;
149 struct ctl_table_root
*root
;
150 struct ctl_table_set
*set
;
151 struct ctl_dir
*parent
;
152 struct ctl_node
*node
;
153 struct hlist_head inodes
; /* head for proc_inode->sysctl_inodes */
157 /* Header must be at the start of ctl_dir */
158 struct ctl_table_header header
;
162 struct ctl_table_set
{
163 int (*is_seen
)(struct ctl_table_set
*);
167 struct ctl_table_root
{
168 struct ctl_table_set default_set
;
169 struct ctl_table_set
*(*lookup
)(struct ctl_table_root
*root
);
170 void (*set_ownership
)(struct ctl_table_header
*head
,
171 struct ctl_table
*table
,
172 kuid_t
*uid
, kgid_t
*gid
);
173 int (*permissions
)(struct ctl_table_header
*head
, struct ctl_table
*table
);
176 /* struct ctl_path describes where in the hierarchy a table is added */
178 const char *procname
;
183 void proc_sys_poll_notify(struct ctl_table_poll
*poll
);
185 extern void setup_sysctl_set(struct ctl_table_set
*p
,
186 struct ctl_table_root
*root
,
187 int (*is_seen
)(struct ctl_table_set
*));
188 extern void retire_sysctl_set(struct ctl_table_set
*set
);
190 struct ctl_table_header
*__register_sysctl_table(
191 struct ctl_table_set
*set
,
192 const char *path
, struct ctl_table
*table
);
193 struct ctl_table_header
*__register_sysctl_paths(
194 struct ctl_table_set
*set
,
195 const struct ctl_path
*path
, struct ctl_table
*table
);
196 struct ctl_table_header
*register_sysctl(const char *path
, struct ctl_table
*table
);
197 struct ctl_table_header
*register_sysctl_table(struct ctl_table
* table
);
198 struct ctl_table_header
*register_sysctl_paths(const struct ctl_path
*path
,
199 struct ctl_table
*table
);
201 void unregister_sysctl_table(struct ctl_table_header
* table
);
203 extern int sysctl_init(void);
205 extern struct ctl_table sysctl_mount_point
[];
207 #else /* CONFIG_SYSCTL */
208 static inline struct ctl_table_header
*register_sysctl_table(struct ctl_table
* table
)
213 static inline struct ctl_table_header
*register_sysctl_paths(
214 const struct ctl_path
*path
, struct ctl_table
*table
)
219 static inline struct ctl_table_header
*register_sysctl(const char *path
, struct ctl_table
*table
)
224 static inline void unregister_sysctl_table(struct ctl_table_header
* table
)
228 static inline void setup_sysctl_set(struct ctl_table_set
*p
,
229 struct ctl_table_root
*root
,
230 int (*is_seen
)(struct ctl_table_set
*))
234 #endif /* CONFIG_SYSCTL */
236 int sysctl_max_threads(struct ctl_table
*table
, int write
,
237 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
);
239 #endif /* _LINUX_SYSCTL_H */