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1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : /*
3 : * sysctl.h: General linux system control interface
4 : *
5 : * Begun 24 March 1995, Stephen Tweedie
6 : *
7 : ****************************************************************
8 : ****************************************************************
9 : **
10 : ** WARNING:
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.
18 : **
19 : ****************************************************************
20 : ****************************************************************
21 : */
22 : #ifndef _LINUX_SYSCTL_H
23 : #define _LINUX_SYSCTL_H
24 :
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>
31 :
32 : /* For the /proc/sys support */
33 : struct completion;
34 : struct ctl_table;
35 : struct nsproxy;
36 : struct ctl_table_root;
37 : struct ctl_table_header;
38 : struct ctl_dir;
39 :
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])
51 :
52 : /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
53 : #define SYSCTL_MAXOLDUID ((void *)&sysctl_vals[10])
54 :
55 : extern const int sysctl_vals[];
56 :
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])
60 :
61 : extern const unsigned long sysctl_long_vals[];
62 :
63 : typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer,
64 : size_t *lenp, loff_t *ppos);
65 :
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 *,
78 : loff_t *);
79 : int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *,
80 : loff_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 *,
83 : size_t *, loff_t *);
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);
87 :
88 : /*
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.
93 : *
94 : * sysctl names can be mirrored automatically under /proc/sys. The
95 : * procname supplied controls /proc naming.
96 : *
97 : * The table's mode will be honoured for proc-fs access.
98 : *
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.
102 : *
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.
106 : *
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.
111 : */
112 :
113 : /* Support for userspace poll() to watch for changes */
114 : struct ctl_table_poll {
115 : atomic_t event;
116 : wait_queue_head_t wait;
117 : };
118 :
119 : static inline void *proc_sys_poll_event(struct ctl_table_poll *poll)
120 : {
121 0 : return (void *)(unsigned long)atomic_read(&poll->event);
122 : }
123 :
124 : #define __CTL_TABLE_POLL_INITIALIZER(name) { \
125 : .event = ATOMIC_INIT(0), \
126 : .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) }
127 :
128 : #define DEFINE_CTL_TABLE_POLL(name) \
129 : struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name)
130 :
131 : /* A sysctl table is an array of struct ctl_table: */
132 : struct ctl_table {
133 : const char *procname; /* Text ID for /proc/sys, or zero */
134 : void *data;
135 : int maxlen;
136 : umode_t mode;
137 : struct ctl_table *child; /* Deprecated */
138 : proc_handler *proc_handler; /* Callback for text formatting */
139 : struct ctl_table_poll *poll;
140 : void *extra1;
141 : void *extra2;
142 : } __randomize_layout;
143 :
144 : struct ctl_node {
145 : struct rb_node node;
146 : struct ctl_table_header *header;
147 : };
148 :
149 : /* struct ctl_table_header is used to maintain dynamic lists of
150 : struct ctl_table trees. */
151 : struct ctl_table_header {
152 : union {
153 : struct {
154 : struct ctl_table *ctl_table;
155 : int used;
156 : int count;
157 : int nreg;
158 : };
159 : struct rcu_head rcu;
160 : };
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 */
168 : };
169 :
170 : struct ctl_dir {
171 : /* Header must be at the start of ctl_dir */
172 : struct ctl_table_header header;
173 : struct rb_root root;
174 : };
175 :
176 : struct ctl_table_set {
177 : int (*is_seen)(struct ctl_table_set *);
178 : struct ctl_dir dir;
179 : };
180 :
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);
188 : };
189 :
190 : /* struct ctl_path describes where in the hierarchy a table is added */
191 : struct ctl_path {
192 : const char *procname;
193 : };
194 :
195 : #ifdef CONFIG_SYSCTL
196 :
197 : #define DECLARE_SYSCTL_BASE(_name, _table) \
198 : static struct ctl_table _name##_base_table[] = { \
199 : { \
200 : .procname = #_name, \
201 : .mode = 0555, \
202 : .child = _table, \
203 : }, \
204 : { }, \
205 : }
206 :
207 : extern int __register_sysctl_base(struct ctl_table *base_table);
208 :
209 : #define register_sysctl_base(_name) __register_sysctl_base(_name##_base_table)
210 :
211 : void proc_sys_poll_notify(struct ctl_table_poll *poll);
212 :
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);
217 :
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);
228 :
229 : void unregister_sysctl_table(struct ctl_table_header * table);
230 :
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);
236 :
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,
241 : unsigned int *valp,
242 : int write, void *data),
243 : void *data);
244 :
245 : extern int pwrsw_enabled;
246 : extern int unaligned_enabled;
247 : extern int unaligned_dump_stack;
248 : extern int no_unaligned_warning;
249 :
250 : extern struct ctl_table sysctl_mount_point[];
251 :
252 : #else /* CONFIG_SYSCTL */
253 :
254 : #define DECLARE_SYSCTL_BASE(_name, _table)
255 :
256 : static inline int __register_sysctl_base(struct ctl_table *base_table)
257 : {
258 : return 0;
259 : }
260 :
261 : #define register_sysctl_base(table) __register_sysctl_base(table)
262 :
263 : static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
264 : {
265 : return NULL;
266 : }
267 :
268 : static inline struct ctl_table_header *register_sysctl_mount_point(const char *path)
269 : {
270 : return NULL;
271 : }
272 :
273 : static inline struct ctl_table_header *register_sysctl_paths(
274 : const struct ctl_path *path, struct ctl_table *table)
275 : {
276 : return NULL;
277 : }
278 :
279 : static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table)
280 : {
281 : return NULL;
282 : }
283 :
284 : static inline void unregister_sysctl_table(struct ctl_table_header * table)
285 : {
286 : }
287 :
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 *))
291 : {
292 : }
293 :
294 : static inline void do_sysctl_args(void)
295 : {
296 : }
297 : #endif /* CONFIG_SYSCTL */
298 :
299 : int sysctl_max_threads(struct ctl_table *table, int write, void *buffer,
300 : size_t *lenp, loff_t *ppos);
301 :
302 : #endif /* _LINUX_SYSCTL_H */
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