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 /* Keep the same order as in fs/proc/proc_sysctl.c */
41 #define SYSCTL_NEG_ONE ((void *)&sysctl_vals[0])
42 #define SYSCTL_ZERO ((void *)&sysctl_vals[1])
43 #define SYSCTL_ONE ((void *)&sysctl_vals[2])
44 #define SYSCTL_TWO ((void *)&sysctl_vals[3])
45 #define SYSCTL_FOUR ((void *)&sysctl_vals[4])
46 #define SYSCTL_ONE_HUNDRED ((void *)&sysctl_vals[5])
47 #define SYSCTL_TWO_HUNDRED ((void *)&sysctl_vals[6])
48 #define SYSCTL_ONE_THOUSAND ((void *)&sysctl_vals[7])
49 #define SYSCTL_THREE_THOUSAND ((void *)&sysctl_vals[8])
50 #define SYSCTL_INT_MAX ((void *)&sysctl_vals[9])
52 /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
53 #define SYSCTL_MAXOLDUID ((void *)&sysctl_vals[10])
55 extern const int sysctl_vals[];
57 #define SYSCTL_LONG_ZERO ((void *)&sysctl_long_vals[0])
58 #define SYSCTL_LONG_ONE ((void *)&sysctl_long_vals[1])
59 #define SYSCTL_LONG_MAX ((void *)&sysctl_long_vals[2])
61 extern const unsigned long sysctl_long_vals[];
63 typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer,
64 size_t *lenp, loff_t *ppos);
66 int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *);
67 int proc_dobool(struct ctl_table *table, int write, void *buffer,
68 size_t *lenp, loff_t *ppos);
69 int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *);
70 int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *);
71 int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
72 int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer,
73 size_t *lenp, loff_t *ppos);
74 int proc_dou8vec_minmax(struct ctl_table *table, int write, void *buffer,
75 size_t *lenp, loff_t *ppos);
76 int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *);
77 int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *,
79 int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *,
81 int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
82 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *,
84 int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *);
85 int proc_do_static_key(struct ctl_table *table, int write, void *buffer,
86 size_t *lenp, loff_t *ppos);
89 * Register a set of sysctl names by calling register_sysctl_table
90 * with an initialised array of struct ctl_table's. An entry with
91 * NULL procname terminates the table. table->de will be
92 * set up by the registration and need not be initialised in advance.
94 * sysctl names can be mirrored automatically under /proc/sys. The
95 * procname supplied controls /proc naming.
97 * The table's mode will be honoured for proc-fs access.
99 * Leaf nodes in the sysctl tree will be represented by a single file
100 * under /proc; non-leaf nodes will be represented by directories. A
101 * null procname disables /proc mirroring at this node.
103 * The data and maxlen fields of the ctl_table
104 * struct enable minimal validation of the values being written to be
105 * performed, and the mode field allows minimal authentication.
107 * There must be a proc_handler routine for any terminal nodes
108 * mirrored under /proc/sys (non-terminals are handled by a built-in
109 * directory handler). Several default handlers are available to
110 * cover common cases.
113 /* Support for userspace poll() to watch for changes */
114 struct ctl_table_poll {
116 wait_queue_head_t wait;
119 static inline void *proc_sys_poll_event(struct ctl_table_poll *poll)
121 return (void *)(unsigned long)atomic_read(&poll->event);
124 #define __CTL_TABLE_POLL_INITIALIZER(name) { \
125 .event = ATOMIC_INIT(0), \
126 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) }
128 #define DEFINE_CTL_TABLE_POLL(name) \
129 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name)
131 /* A sysctl table is an array of struct ctl_table: */
133 const char *procname; /* Text ID for /proc/sys, or zero */
137 struct ctl_table *child; /* Deprecated */
138 proc_handler *proc_handler; /* Callback for text formatting */
139 struct ctl_table_poll *poll;
142 } __randomize_layout;
146 struct ctl_table_header *header;
149 /* struct ctl_table_header is used to maintain dynamic lists of
150 struct ctl_table trees. */
151 struct ctl_table_header {
154 struct ctl_table *ctl_table;
161 struct completion *unregistering;
162 struct ctl_table *ctl_table_arg;
163 struct ctl_table_root *root;
164 struct ctl_table_set *set;
165 struct ctl_dir *parent;
166 struct ctl_node *node;
167 struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */
171 /* Header must be at the start of ctl_dir */
172 struct ctl_table_header header;
176 struct ctl_table_set {
177 int (*is_seen)(struct ctl_table_set *);
181 struct ctl_table_root {
182 struct ctl_table_set default_set;
183 struct ctl_table_set *(*lookup)(struct ctl_table_root *root);
184 void (*set_ownership)(struct ctl_table_header *head,
185 struct ctl_table *table,
186 kuid_t *uid, kgid_t *gid);
187 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table);
190 /* struct ctl_path describes where in the hierarchy a table is added */
192 const char *procname;
197 #define DECLARE_SYSCTL_BASE(_name, _table) \
198 static struct ctl_table _name##_base_table[] = { \
200 .procname = #_name, \
207 extern int __register_sysctl_base(struct ctl_table *base_table);
209 #define register_sysctl_base(_name) __register_sysctl_base(_name##_base_table)
211 void proc_sys_poll_notify(struct ctl_table_poll *poll);
213 extern void setup_sysctl_set(struct ctl_table_set *p,
214 struct ctl_table_root *root,
215 int (*is_seen)(struct ctl_table_set *));
216 extern void retire_sysctl_set(struct ctl_table_set *set);
218 struct ctl_table_header *__register_sysctl_table(
219 struct ctl_table_set *set,
220 const char *path, struct ctl_table *table);
221 struct ctl_table_header *__register_sysctl_paths(
222 struct ctl_table_set *set,
223 const struct ctl_path *path, struct ctl_table *table);
224 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table);
225 struct ctl_table_header *register_sysctl_table(struct ctl_table * table);
226 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
227 struct ctl_table *table);
229 void unregister_sysctl_table(struct ctl_table_header * table);
231 extern int sysctl_init_bases(void);
232 extern void __register_sysctl_init(const char *path, struct ctl_table *table,
233 const char *table_name);
234 #define register_sysctl_init(path, table) __register_sysctl_init(path, table, #table)
235 extern struct ctl_table_header *register_sysctl_mount_point(const char *path);
237 void do_sysctl_args(void);
238 int do_proc_douintvec(struct ctl_table *table, int write,
239 void *buffer, size_t *lenp, loff_t *ppos,
240 int (*conv)(unsigned long *lvalp,
242 int write, void *data),
245 extern int pwrsw_enabled;
246 extern int unaligned_enabled;
247 extern int unaligned_dump_stack;
248 extern int no_unaligned_warning;
250 extern struct ctl_table sysctl_mount_point[];
252 #else /* CONFIG_SYSCTL */
254 #define DECLARE_SYSCTL_BASE(_name, _table)
256 static inline int __register_sysctl_base(struct ctl_table *base_table)
261 #define register_sysctl_base(table) __register_sysctl_base(table)
263 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
268 static inline struct ctl_table_header *register_sysctl_mount_point(const char *path)
273 static inline struct ctl_table_header *register_sysctl_paths(
274 const struct ctl_path *path, struct ctl_table *table)
279 static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table)
284 static inline void unregister_sysctl_table(struct ctl_table_header * table)
288 static inline void setup_sysctl_set(struct ctl_table_set *p,
289 struct ctl_table_root *root,
290 int (*is_seen)(struct ctl_table_set *))
294 static inline void do_sysctl_args(void)
297 #endif /* CONFIG_SYSCTL */
299 int sysctl_max_threads(struct ctl_table *table, int write, void *buffer,
300 size_t *lenp, loff_t *ppos);
302 #endif /* _LINUX_SYSCTL_H */